JP2016009066A - Electrophotographic photosensitive member, image forming method using the same, image forming apparatus and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor configured to minimize a friction coefficient and wear even after a long-term use, while improving cleaning performance.SOLUTION: An electrophotographic photoreceptor includes, on a conductive support, at least: a photosensitive layer; and a surface layer containing curable resin having a crosslinked structure, a lubricant material, and a dispersion aid. The curable resin is a cured material formed by curing polyfunctional thiol having two or more functional groups, a mono-functional radical polymerizable compound having a charge-transporting structure, a radical polymerizable monomer (including a monomer having at least three radical polymerizable functional groups) having no charge-transporting structure. The content of the lubricant material is controlled to fall within a range of 5-50 percent by weight with respect to the total solid in the surface layer. The content of the dispersion aid is controlled to fall within a range of 2-20 percent by weight with respect to the total solid in the surface layer.

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming method using the same, an image forming apparatus, and a process cartridge for the image forming apparatus.

Electrophotographic photoconductors used in electrophotographic image forming devices (electrophotographic devices) applied to copiers and laser printers were the days when inorganic photoconductors such as selenium, zinc oxide and cadmium sulfide were the mainstream. As a result, organic photoconductors (OPCs), which are more advantageous than inorganic photoconductors due to reduced burden on the global environment, cost reduction, and high design freedom, now account for 100% of the total production of electrophotographic photoconductors. It is used at a rate of thinning. Thus, in recent years, organic photoreceptors are widely used for electrophotographic photoreceptors.
Organic photoreceptors are advantageous over inorganic photoreceptors due to the fact that materials that can be used for various exposure light sources from visible light to infrared light can be easily developed, materials that are free from environmental pollution can be selected, and manufacturing costs are low. There are many points. However, organic photoconductors have weak physical and chemical strengths, and have drawbacks such that wear and scratches are likely to occur due to long-term use.
An electrophotographic image forming apparatus generally includes an electrophotographic photosensitive member, a charging member that charges the electrophotographic photosensitive member, and a latent image that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging member. A forming member, a developing member that attaches toner to an image portion of an electrostatic latent image formed by the latent image forming member, and a transfer member that transfers the toner attached to the image portion to a transfer target are integrally provided. In some cases, a cleaning member for removing toner remaining on the surface of the electrophotographic photosensitive member without being transferred is provided as necessary.
Since toner remaining on the surface of the electrophotographic photosensitive member after the transfer contributes to deterioration of image quality, a cleaning member is employed in many image forming apparatuses. As the cleaning member, a brush, a magnetic brush, a blade, or the like is generally used. Polyester and acrylic fibers are used for brush cleaning, and are used after optimization by changing the shape of the loop or straight hair, the hardness and thickness of the fibers, and the like. However, brush cleaning does not sufficiently remove fine toner, and is difficult to remove sufficiently, such as slipping between fibers. The same applies to magnetic brushes, and in this method, attempts have been made to remove electrostatically by applying an electric field. However, the phenomenon that toner scattered by electrostatic force adheres to the electrophotographic photoreceptor again occurs. Thorough cleaning is difficult. Therefore, as the current cleaning means, blade cleaning using an elastic blade is mainly used from the standpoint of removal of residual toner, cost, and diameter reduction. In blade cleaning, the surface layer of the electrophotographic photosensitive member slides in contact with the cleaning blade and the toner, so that mechanical wear and scratches are likely to occur on the surface of the electrophotographic photosensitive member. In recent years, the life expectancy of a photoconductor has been eagerly desired due to an increase in environmental awareness, and as a countermeasure, a protective layer is generally added on the photosensitive layer.

In addition, as a developing toner used for electrophotographic image formation, polymerized toner (spherical toner) is becoming the mainstream because it is advantageous in improving the reduction of the global environmental load during toner production and improving the image quality. is there. Since the polymerized toner has a uniform shape, the electric charge to be held is relatively easy to align. Moreover, it is easy to add wax internally. Therefore, since there is almost no protrusion from an electrostatic latent image, developability is good, sharpness, resolution, and gradation are excellent, and transfer efficiency is also good. In addition, there are many advantages such as eliminating the need for oil during transfer. Many of such polymerized toners have a small particle size.
In an image forming apparatus using a toner having a small particle diameter, the ratio of toner remaining on the surface of the electrophotographic photoreceptor after transfer passes through the cleaning blade increases. In particular, when the dimensional accuracy and assembly accuracy of the cleaning blade are not sufficient, or when the cleaning blade partially vibrates, the toner slips through more and prevents high-quality image formation.
For this reason, in order to further extend the life of the electrophotographic photosensitive member and maintain high-quality image formation over a long period of time, it is necessary to reduce deterioration of the member due to friction and improve cleaning properties. As described above, it is well known that when a toner having a small particle diameter is used, it is difficult to clean, and various methods have been proposed for this countermeasure.

As a method for reducing the friction between the electrophotographic photosensitive member and the cleaning blade, for example, a lubricating material is supplied to the surface of the electrophotographic photosensitive member, and the supplied lubricating material is uniformly applied by a cleaning blade or the like. A method of forming a film of a lubricious material on the surface of a photoreceptor has been proposed (see Patent Document 1).
However, when a lubricating material is used, if the amount of the lubricating material applied is too small, the electrophotographic photosensitive member may not be sufficiently effective against abrasion, scratches, and deterioration of the cleaning blade. On the other hand, if an excessive amount of lubricating material is applied, excess lubricating material accumulates on the surface of the electrophotographic photosensitive member, resulting in abnormal images such as image blur, or excessive lubricating material is mixed into the developer. Therefore, it is necessary to control the application amount of the lubricating material. In addition, since the lubricating material applied to the surface of the electrophotographic photosensitive member is removed by the cleaning blade, it is necessary to continue applying the lubricating material during the image forming process. Therefore, the lubricating material becomes a consumable material. The amount of the lubricating material that can be mounted on the lubricating material application means of the image forming apparatus is limited because the space of the image forming apparatus is limited, so that only a certain amount can be mounted. The life of the image forming apparatus is shortened, and work for newly mounting a lubricant material is generated, so that the downtime of the image forming apparatus is caused and the productivity of image formation is impaired. Due to such problems, there is a demand for an image forming apparatus that does not require a lubricating material applying unit and can realize high-quality image formation over a long period of time.
It is also known to increase the hardness of the surface of the cleaning blade for the purpose of maintaining cleaning properties for a long period of time. As a result, the wear and deformation of the cleaning blade can be suppressed, so that it is possible to maintain the cleaning performance for a long period of time, but the side effect of increasing the wear amount of the contacted electrophotographic photosensitive member is large, and the entire system is The lifetime of was not satisfactory.

As means for improving the cleaning performance, means containing a lubricant such as a silicone compound, fluororesin fine particles and fatty acid ester is generally known. In particular, for the cleaning property of polymerized toner, means for containing fluororesin fine particles in the outermost layer of the photoreceptor has been proposed (see Patent Document 2 and Patent Document 3).
In order to reduce the coefficient of friction on the surface of the photoconductor, it is necessary to contain the fluororesin fine particles at a concentration of a predetermined amount or more. Will shrink. Furthermore, in order to disperse a large amount of the fluororesin fine particles, it is necessary to increase the amount of the dispersion aid at the same time. There are concerns about adverse effects on properties. Further, when the amount of the dispersion aid added is increased, bubbles are easily generated in the coating solution, and it is difficult to stably produce the photoreceptor.

It has been reported that the surface of the electrophotographic photosensitive member is increased in hardness with respect to the problems as described above. For example, in Patent Document 4 and Patent Document 5, when a magnetic brush type is applied as a charger, unintended magnetic particles are transferred onto an electrophotographic photosensitive member, and the particles are electrophotographic in a transfer portion or a cleaning portion. It has been proposed to increase the hardness of the surface layer of the electrophotographic photosensitive member in order to prevent the surface from being scratched by being strongly pressed against the photosensitive member. Patent Document 6 proposes to increase the hardness of the surface of the electrophotographic photosensitive member in order to suppress wear of the electrophotographic photosensitive member when the blade type cleaning method is applied. As a specific means for increasing the hardness of such an electrophotographic photosensitive member surface, it is proposed that a crosslinkable material such as a thermosetting resin or a UV curable resin is used as a constituent component of the electrophotographic photosensitive member surface layer. Has been. For example, Patent Document 7, Patent Document 8 and Patent Document 9 propose a method for improving the wear resistance and scratch resistance of a surface layer by applying a thermosetting resin as a binder component of the surface layer.
Further, in Patent Document 10, Patent Document 11 and Patent Document 12, it is proposed to improve wear resistance and scratch resistance by using a siloxane resin having a crosslinked structure as a charge transport material. Further, in Patent Document 13, Patent Document 14, and the like, in order to improve wear resistance and scratch resistance, both a binder and a charge transport material have a monomer having a carbon-carbon double bond, and a charge transport having a carbon-carbon double bond. Techniques using materials and binder resins have been proposed.
In Patent Document 15, a trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure, a radical polymerizable monomer compound having a charge transporting structure, and a chain transfer agent containing a thiol group were cured by light energy irradiation. It has been proposed to provide a surface layer of a crosslinking material on the electrophotographic photoreceptor. Although this technology uses light energy for curing, charge generation materials and charge transport materials used in electrophotographic photoreceptors are easily damaged by light, and the material deteriorates due to light energy during curing. The electrical characteristics and stability were lowered, and it was difficult to form high-quality images over a long period of time. Further, Patent Document 16 and Patent Document 17 propose a thermosetting surface layer using a polyfunctional thiol as a chain transfer agent, and a high wear resistance by forming a charge transport film excellent in flexibility and toughness. However, there has been a side effect that the amount of wear of the cleaning blade in contact with the surface of the electrophotographic photosensitive member is increased without detailed examination of the content of the lubricating material and the dispersion aid. Since the foreign matter such as toner cannot be removed when the cleaning blade is worn, abnormal images such as white spots may be caused and the performance is not sufficient.
Even in the case of using an electrophotographic photosensitive member having a high surface hardness as described above, high-quality image formation over a very long period of time has not been realized.

  The present invention has been made in view of the above prior art, and an object of the present invention is to provide an electrophotographic photosensitive member that has an extremely low coefficient of friction and wear even when used for a long period of time and is excellent in cleaning properties.

As a result of intensive studies, the present inventors have found that a coating liquid for a surface layer used for forming a surface layer comprising a cured resin having a crosslinked structure (crosslinked type cured resin), a lubricating material, and a dispersion aid. With regard to the use of a specific component for cured resin, and by controlling the content of the lubricating material and the content of the dispersion aid, the lubricating material exhibits high dispersion stability, and even if the blending ratio is increased The present inventors have found that coating defects are suppressed, are uniformly dispersed over the entire surface layer, wear is extremely small even when used for a long time, and that they have excellent leaning properties.
That is, the above problem is in an electrophotographic photosensitive member having at least a photosensitive layer and a surface layer on a conductive support.
The surface layer contains a cured resin having a crosslinked structure, a lubricating material, and a dispersion aid,
The cured resin is a cured product of a polyfunctional thiol having two or more functional groups, a monofunctional radical polymerizable compound having a charge transporting structure, and a radical polymerizable monomer having no charge transporting structure. And the content of the lubricating material is in the range of 5 to 50% by weight with respect to the total solid content of the surface layer, and the content of the dispersion aid is 2 to 2 with respect to the total solid content of the surface layer. This is solved by an electrophotographic photosensitive member characterized by being in the range of 20% by weight.

  According to the electrophotographic photosensitive member of the present invention, it is possible to provide an electrophotographic photosensitive member that has an extremely small coefficient of friction and wear even when used for a long period of time and that has excellent cleaning properties.

It is the schematic which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. It is the schematic which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. It is the schematic which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. It is the schematic which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows an example of the process cartridge of this invention. It is a conceptual diagram which shows the evaluation method of the surface friction coefficient in an Example.

As described above, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having at least a photosensitive layer and a surface layer on a conductive support, a cured resin having a crosslinked structure in the surface layer, a lubricating material, The curing resin contains a polyfunctional thiol having two or more functional groups, a monofunctional radical polymerizable compound having a charge transporting structure, and a radical having no charge transporting structure. It is a cured product with a polymerizable monomer, and the content of the lubricating material is in the range of 5 to 50% by weight with respect to the total solid content of the surface layer, and the content of the dispersion aid is the surface layer It is characterized by being in the range of 2 to 20% by weight with respect to the total solid content.
The electrophotographic photoreceptor of the present invention has an extremely small increase in friction coefficient and wear during long-term use or large-scale printing, excellent cleaning properties, stable electrical characteristics, and quality of images output from the image forming apparatus. Can be maintained at an excellent level over a long period of time. It is possible to solve the conventional problems. An electrophotographic apparatus using this photoconductor is excellent in practical value that can provide an electrophotographic apparatus capable of forming an image with polymerized toner without providing a lubricant external supply means to the photoconductor.

That is, as a result of intensive research, the present inventors have found that the surface layer has a polyfunctional thiol having two or more functional groups, a monofunctional radical polymerizable compound having a charge transporting structure, and a charge transporting structure. Is applied using a surface layer coating solution containing a radically polymerizable monomer, a lubricating material, and a dispersion aid, and is formed by treatment by at least one of heating and light energy irradiation. In the surface layer coating liquid to be obtained, the content of the lubricating material is in the range of 5 to 50% by weight with respect to the total solid content of the surface layer, and the content of the dispersion aid is equal to the total solid content of the surface layer. On the other hand, it has been found that the lubricating material exhibits high dispersion stability when the content is within the range of 2 to 20% by weight.
If the amount of the lubricating material added is less than 5% by weight, the low friction cannot be maintained. On the other hand, if the addition amount of the lubricating material exceeds 50% by weight, the wear resistance of the surface layer (surface cross-linked film) is impaired, the sensitivity on the electrostatic characteristics cannot be obtained, or the surface property is remarkably lowered. In practice, problems due to the blending of the lubricating material become stronger.
By applying a surface layer coating solution with good dispersibility of the lubricating material thus adjusted on the photosensitive layer, a uniform surface layer (surface cross-linked film) with less unevenness can be formed. Even when such a highly circular toner is used, wear is small and good cleaning properties are exhibited.

Moreover, a surface layer (surface crosslinked film) is formed by processing by at least one of heating and light energy irradiation. That is, in the formation of the surface layer, heat treatment alone or light energy irradiation alone may be used, or light energy irradiation and heat treatment may be combined. For example, in the case of forming a surface cross-linked film by light energy irradiation means, in general, the increase in the surface temperature of the photoconductor during cross-linking is suppressed, and the aggregating action between the lubricating materials due to the temperature rise can be prevented. It is possible to obtain a surface layer excellent in cleanability without coating defects without lowering the dispersibility of the conductive material.
Furthermore, since the cross-linking reaction proceeds while the polyfunctional thiol having two or more functional groups captures oxygen, a high reaction rate can be obtained, which brings about an effect of improving wear resistance.
As a result, the friction coefficient rises and wears extremely little even after long-term use, the electrical characteristics are stable, and the removal of foreign matters such as toner by the cleaning member is performed without delay, so that no abnormal image is generated, It is possible to provide an electrophotographic photosensitive member that maintains excellent image quality. By using the electrophotographic photosensitive member of the present invention, it is possible to provide an electrophotographic apparatus that forms an image without providing a lubricant external supply means for supplying a lubricant to the photosensitive member from the outside.
Hereinafter, the “electrophotographic photosensitive member” may be abbreviated as “photosensitive member”.
In addition, “polyfunctional thiol having two or more functional groups” is referred to as “polyfunctional thiol” or abbreviated as “thiol compound”, and “monofunctional radical polymerizable compound having a charge transporting structure” as “radical polymerizable compound”. ”Or abbreviated“ radical compound ”and“ radical polymerizable monomer having no charge transport structure ”may be referred to as“ radical polymerizable monomer ”or abbreviated“ radical monomer ”, respectively.

[Electrophotographic photoreceptor]
<Configuration of electrophotographic photoreceptor>
The electrophotographic photoreceptor (photoreceptor) of the present invention is a laminate having at least a photosensitive layer and a surface layer in this order on a conductive support. The photosensitive layer may have a single layer structure or a multilayer structure as long as it has a charge generation function and a charge transport function. An example of the embodiment will be described with reference to FIGS.
The cross-sectional view of the electrophotographic photosensitive member shown in FIG. 1 is an example in the case where the photosensitive layer is a single layer, and a photosensitive layer mainly composed of a charge generating substance and a charge transporting substance on a conductive support (31). (34) and a surface layer (35) are provided. The surface layer (35) described here represents the surface cross-linked film (cross-linkable surface layer) described above or below.
The cross-sectional views of the electrophotographic photosensitive member shown in FIGS. 2 and 3 are examples in the case where the photosensitive layer itself also has a laminated structure, and the charge generation layer (37) having a charge generation function on the conductive support (31). And a charge transport layer (38) having a charge transport function are separated and laminated. In the case of taking this embodiment, the order of stacking the charge generation layer (37) and the charge transport layer (38) on the conductive support (31) is not particularly limited as shown in the figure, and is properly used depending on the application. A surface layer (35) is further laminated on the outermost surface of the photoreceptor.
The cross-sectional view of the electrophotographic photosensitive member shown in FIG. 4 is an example in the case where the photosensitive layer has a laminated structure as in FIG. 2, and is provided on the conductive support (31) via the undercoat layer (32). A charge generation layer (37) and a charge transport layer (38) are provided. A surface layer (35) is laminated on the outermost surface of the photoreceptor.
If necessary, another layer [for example, an adhesive layer between the surface layer and the photosensitive layer (single layer or laminated structure)] may be provided.
The electrophotographic photoreceptor of the present invention has a material defined in the present invention (containing at least a cured resin having a crosslinked structure, a lubricating material, and a dispersion aid) on the surface layer, and the conductive support, As for the photosensitive layer and the other layers, those similar to the conventional ones can be applied.

The surface layer constituting the electrophotographic photosensitive member will be described in detail below.
[Surface layer]
As described above, the surface layer contains a cured resin having a crosslinked structure (crosslinked type cured resin), a lubricating material, and a dispersion aid, and the crosslinked type cured resin has a number of functional groups of 2 or more. It consists of a cured product of a functional thiol, a monofunctional radical polymerizable compound having a charge transporting structure, and a radical polymerizable monomer not having a charge transporting structure, and further containing other components as necessary. Become.
Hereinafter, the “monofunctional radically polymerizable compound having a charge transporting structure” may be referred to as “donor”.
Each material forming the cross-linked curable resin will be described in detail.

<Each material forming a cured product having a crosslinked structure>
(Multifunctional thiol having 2 or more functional groups)
The polyfunctional thiol having two or more functional groups used in the present invention will be described.
A compound having a thiol group (SH group) in one molecule is generally called a thiol compound, and a sulfur radical is generated in one molecule by a hydrogen-sulfur bond cleavage reaction. Polymer having a crosslinked structure from a polyfunctional thiol, a monofunctional radical polymerizable compound having a charge transporting structure, and a radical polymerizable monomer having no charge transporting structure due to generation of a sulfur radical [cured resin having a crosslinked structure (Crosslinked curing resin)] can be formed.
Here, a compound having two or more SH groups is desirable from the viewpoint of obtaining good abrasion resistance from the improvement of the crosslinking density and reducing unreacted SH groups. As a result, the influence of oxygen inhibition can be reduced and at the same time sufficient crosslinking density can be improved. Further, since the amount of the initiator can be reduced, the monofunctional radically polymerizable compound (donor) having a charge transporting structure is hardly deteriorated, and good electrical characteristics can be maintained over a long period of time.
In addition, the ene-thiol reaction peculiar to thiol compounds can capture oxygen by the reaction mechanism shown in the following reaction formula (1), so that a high monomer reaction rate can be obtained by reducing oxygen inhibition. It is possible to expect an improvement in the crosslinking density.

The mechanism that reduces the influence of oxygen inhibition is that thiol compounds that have hydrogen that can be easily extracted can generate thiyl radicals by extracting hydrogen to peroxide radicals that are inert to radical polymerization, which contributes to polymerization. Because of this, the influence of oxygen inhibition can be reduced.
In the present invention, a thiol compound having two or more thiol groups is used, and even when a thiol compound is incorporated into a crosslinked structure by one thiol group, the remaining thiol groups can be further polymerized and crosslinked. The density can be sufficiently improved.
When a monofunctional thiol compound (compound having one primary thiol group) is used, the polymerization and cross-linking reactions are suppressed by capping at the end, so that improvement in molecular weight cannot be expected, and the abrasion resistance of the surface layer It is difficult to improve the performance.

The following are mentioned as an example of the thiol compound which can be used for this invention.
Examples of the compound containing two thiol groups include oligomeric compounds such as 1,4-bis (3-mercaptobutyryloxy) butane and tetraethylene glycol-bis (3-mercaptopropionate).
Examples of the compound containing three thiol groups include trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, 1,2,6-hexane. Triol trithioglycolate, 1,3,5-trithiocyanuric acid, trimethylolpropane tristhioglycolate, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3,5-triazine-2, 4,6 (1H, 3H, 5H) -trione, trimethylolpropane tristhiopropionate, trihydroxyethyltriisocyanuric acid tristhiopropionate, tris [(3-mercaptopropionyloxy) ethyl] isocyanurate, etc. Is mentioned.
Examples of the compound containing four thiol groups include pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, and the like.
Examples of the compound containing six thiol groups include dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol hexakisthioglycolate, and the like.
Among them, compounds containing 3 or more thiol groups are preferable. Specifically, trimethylolpropane tris (3-mercaptopropionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), dipentaerythritol hexakis (3-mercaptopropionate).

  The content of the polyfunctional thiol compound having two or more functional groups is 1 to 50% by weight, preferably 2 to 30% by weight, based on the total solid content of the surface layer (crosslinked surface layer). If the content is less than 1% by weight, the influence of oxygen inhibition may not be sufficiently reduced, which is not preferable. If the content exceeds 50% by weight, the bifunctional or higher functional group does not have a charge transporting structure having a high crosslinking rate. Since the amount of the radically polymerizable monomer is relatively small, the crosslinking density may be reduced and the wear resistance may be reduced. Since the required wear resistance and electrical characteristics differ depending on the process used, it cannot be said unconditionally, but the range of 2 to 30% by weight is most preferable in consideration of the balance of both characteristics.

(Radically polymerizable monomer that does not have a charge transporting structure)
Examples of the radical polymerizable monomer having no charge transport structure used in the present invention include hole transport structures such as triarylamine, hydrazone, pyrazoline, carbazole, condensed polycyclic quinone, diphenoquinone, cyano group, and the like. A monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a nitro group and having a radical polymerizable functional group.

  The radical polymerizable functional group is not particularly limited as long as it has a carbon-carbon double bond and can be radically polymerized. Examples of such radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

Is mentioned.
(A) As 1-substituted ethylene functional group, the functional group represented by following General formula (2) is mentioned, for example.

[In the formula (2), X ₁ represents an arylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group, a —CON ( R < ₁₀ >)-group (R < ₁₀ > represents hydrogen, an alkyl group, an aralkyl group, an aryl group), or -S- group. ]

Specific examples of the arylene group which may have a substituent include a phenylene group and a naphthylene group. Specific examples of the alkyl group in R ₁₀ include a methyl group and an ethyl group as an aralkyl group. Examples of the aryl group include a benzyl group, a naphthylmethyl group, and a phenethyl group. Examples of the aryl group include a phenyl group and a naphthyl group.

  Specific examples of the substituent represented by the general formula (2) include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether. Groups and the like.

  (B) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following general formula (3).

[In the formula (3), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a halogen atom. , A cyano group, a nitro group, an alkoxy group, a —COOR ₁₁ group (R ₁₁ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. Or -CONR ₁₂ R ₁₃ group (R ₁₂ and R ₁₃ may be a hydrogen atom, an alkyl group which may have a substituent, or a substituent. Represents a good aralkyl group or an aryl group which may have a substituent, and may be the same or different from each other. X ₂ represents the same substituent, single bond, and alkylene group as X _{1 in the} general formula (2). However, at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, or an aromatic ring. ]

Phenyl group Examples of the aryl group which may have a substituent in the Y, naphthyl group and the alkoxy group, a methoxy group or an ethoxy group, and also, the substituents on R ₁₁ Specific examples of the alkyl group that may have a methyl group, an ethyl group, etc., and the aralkyl group that may have a substituent include a benzyl group, a phenethyl group, and the like, which have a substituent. Examples of a good aryl group include a phenyl group and a naphthyl group, and specific examples of the alkyl group which may have a substituent in R ₁₂ and R ₁₃ include a methyl group, an ethyl group, and the like. Examples of the aralkyl group which may be substituted include a benzyl group, a naphthylmethyl group and a phenethyl group, and examples of the aryl group which may have a substituent include a phenyl group and a naphthyl group. It is.
Specific examples of the functional group include an α-acryloyloxy group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

In addition, examples of the substituent further substituted with the substituent for X ₁ , X ₂ , and Y include, for example, halogen groups, nitro groups, cyano groups, methyl groups, ethyl groups and other alkyl groups, methoxy groups, and ethoxy groups. And aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, and aralkyl groups such as benzyl group and phenethyl group.

  Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful.

  In the present invention, the number of functional groups of the radically polymerizable monomer having no charge transporting structure is not particularly limited, but at least one kind of three or more radically polymerizable functional groups is used in order to make the surface layer wear resistant. It is preferable to use a radically polymerizable monomer having a group. When only monofunctional and bifunctional radically polymerizable monomers are used, the cross-linking bond in the cross-linked surface layer may become dilute and it may be difficult to achieve a dramatic improvement in wear resistance. However, when using only a trifunctional or higher-functional radical polymerizable monomer, defects such as a decrease in surface smoothness due to an increase in the viscosity of the coating liquid and a crack due to volume shrinkage during the curing reaction may occur. One or more types of one or more bifunctional radically polymerizable monomers and radically polymerizable oligomers are used in combination for the purpose of adjusting the viscosity of the coating liquid, maintaining the surface smoothness of the surface layer, preventing cracks due to crosslinking shrinkage, and reducing the surface free energy. Also good.

  Examples of the radical polymerizable monomer having no charge transporting structure include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxy Butyl acrylate, benzyl acrylate, cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, 1,3-butanediol diacrylate, 1 , 4-Butanediol diacrylate, 1,4-butanediol dimeta Relate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO modified bisphenol A diacrylate, EO modified bisphenol F diacrylate, neopentyl glycol diacrylate, Trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene modified triacrylate, trimethylolpropane ethyleneoxy modified (hereinafter EO modified) triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate , Trimethylolpropane caprolactone modified triacrylate, trimethylolpropane Lucylene-modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, glycerol epichlorohydrin modified (ECH modified) triacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acrylic) Roxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipenta Erythritol triacrylate, dimethyl Examples include tyrolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2,2,5,5, -tetrahydroxymethylcyclopentanone tetraacrylate, and the like in the present invention. However, the present invention is not limited to these compounds.

The radical polymerizable monomer having no charge transporting structure used in the present invention is not limited, but in order to make the structure of the cured resin contained in the surface layer a dense cross-linked bond, for example, The ratio of molecular weight to the number of functional groups in the monomer (molecular weight / number of functional groups) is preferably 250 or less. Further, when this ratio is larger than 250, the crosslinked surface layer is soft and wear resistance is somewhat lowered. Therefore, among the monomers exemplified above, monomers having a modifying group such as HPA, EO, and PO are extremely long. It is not preferable to use one having a modifying group alone.
The content of the radically polymerizable monomer having no charge transporting structure used in the present invention is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total solid content of the surface layer (crosslinked surface layer). . When the content is less than 20% by weight, the three-dimensional cross-linking density of the cross-linked surface layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is relatively lowered, and the electrical characteristics are deteriorated. Since the required wear resistance and electrical characteristics differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

(Monofunctional radically polymerizable compound having a charge transporting structure)
The monofunctional radically polymerizable compound having a charge transporting structure used in the present invention is, for example, a hole transporting structural part such as triarylamine, hydrazone, pyrazoline, carbazole, or condensed polycyclic quinone, diphenoquinone, A compound having an electron transport structure such as an electron-withdrawing aromatic ring having a cyano group or a nitro group and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups [for example, the general formula (2)], similarly to the functional group contained in the radical polymerizable monomer having no charge transporting structure. Preferred examples include 1,1-substituted ethylene functional groups [for example, the general formula (3)]. In particular, an acryloyloxy group and a methacryloyloxy group are useful.

  Here, when a charge transporting compound having two or more radical polymerizable functional groups is used as the radical polymerizable compound having a radical polymerizable functional group, the surface layer may crack due to crosslinking shrinkage during curing, Due to the residual stress inside the film, the film tends to peel from the surface layer during use. In addition, in terms of electrostatic characteristics, when a charge transporting compound having a radically polymerizable functional group having two or more functional groups is used, it is fixed in a crosslinked structure with a plurality of bonds, so that an intermediate structure during charge transport ( Cation radicals) cannot be kept stable, and the sensitivity is lowered and the residual potential is increased due to charge trapping. Such deterioration of electrical characteristics appears as an image such as a decrease in image density and thinning of characters. From this, it is preferable to use a charge transporting material having a monofunctional radically polymerizable group as a charge transporting compound having a radically polymerizable functional group, While suppressing the generation of cracks and scratches, it makes it easier to stabilize the electrostatic characteristics.

In addition, you may add the charge transport material which does not have a radical polymerizable functional group in the range which does not deviate from the meaning of this invention.
The charge transport material having no radical polymerizable functional group refers to a compound having charge transport performance but not containing a radical polymerizable functional group. Specifically, a hole transport material and an electron transport as shown below are used. Substances.

Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.
Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. Other known materials may be used. These charge transport materials may be used alone or in combination of two or more.

The charge transport structure of the monofunctional radically polymerizable compound having the charge transport structure is preferably a triarylamine structure.
A triarylamine structure is highly effective as a charge transporting structure. Moreover, what has one functional group is preferable, and when a compound shown by the structure of the following general formula (4) or (5) is used, electrical characteristics such as sensitivity and residual potential are favorably sustained.

[In the formulas (4) and (5), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₆ (R ₆ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group), a carbonyl halide group or CONR ₇ R ₈ (R ₇ and R ₈ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or Represents an aryl group which may have a substituent and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and may be the same or different May be. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ]

Specific examples of general formulas (4) and (5) are shown below.
In the general formulas (4) and (5), in the substituent of R ₁ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. However, examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Group, alkyl group such as ethyl group, alkoxy group such as methoxy group and ethoxy group, aryloxy group such as phenoxy group, aryl group such as phenyl group and naphthyl group, aralkyl group such as benzyl group and phenethyl group, etc. It may be. Of the substituents for R ₁ , particularly preferred are a hydrogen atom and a methyl group.

Substituted or unsubstituted Ar ₃ and Ar ₄ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-fused cyclic hydrocarbon groups, and heterocyclic groups.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

  Examples of the non-condensed cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne. , Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or rings such as 9,9-diphenylfluorene Examples thereof include monovalent groups of aggregated hydrocarbon compounds.

  Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.

(1) A halogen atom, a cyano group, a nitro group, etc. are mentioned.
(2) Alkyl groups, preferably C1-C12, especially C1-C8, more preferably C1-C4 linear or branched alkyl groups. These alkyl groups further have a phenyl group substituted with a fluorine atom, a hydroxyl group, a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy group. It may be. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
(3) an alkoxy group (-OR _2). R ₂ represents the alkyl group defined in (2) above. Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) An aryloxy group is mentioned. Examples of the aryl group of the aryloxy group include a phenyl group and a naphthyl group. This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) Alkyl mercapto group or aryl mercapto group may be mentioned. Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.
(6): Examples include a group represented by the following general formula (6).

[In Formula (6), R ₃ and R ₄ each independently represents a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. R ₃ and R ₄ may form a ring together. ]
As said aryl group, a phenyl group, a biphenyl group, or a naphthyl group is mentioned, for example, These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group, or a halogen atom as a substituent. Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

(7) An alkylenedioxy group such as a methylenedioxy group or a methylenedithio group, or an alkylenedithio group.
(8) Substituted or unsubstituted styryl group, substituted or unsubstituted β-phenylstyryl group, diphenylaminophenyl group, ditolylaminophenyl group and the like.

In the general formulas (4) and (5), the substituted or unsubstituted arylene group represented by Ar ₁ or Ar ₂ is a divalent derivative derived from the aryl group represented by Ar ₃ or Ar _4. Groups.

In the general formulas (4) and (5), X (= X ₁ , X ₂ ) is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, substituted or An unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, and a vinylene group are represented.
The substituted or unsubstituted alkylene group is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom and a hydroxyl group. , A cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxy. Examples include ethylene group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.
The substituted or unsubstituted cycloalkylene group is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. It may be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, or tripropylene glycol. The alkylene group of the alkylene ether group is a hydroxyl group, a methyl group, or an ethyl group. You may have substituents, such as group.

  Examples of the vinylene group include groups represented by the following general formula (7) or general formula (8).

[In the formulas (7) and (8), R ₅ is hydrogen, an alkyl group [the same as the alkyl group defined in the above (2)], an aryl group [the same as the aryl group defined in the above Ar ₃ and Ar _4. A represents 1 or 2, and b represents an integer of 1 to 3. ]

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group as described above.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X. Examples of the substituted or unsubstituted alkylene ether group include the alkylene ether group represented by X. Examples of the alkyleneoxycarbonyl group include a caprolactone-modified group.

  Further, the monofunctional radically polymerizable compound having a charge transporting structure of the present invention is more preferably a compound having a structure represented by the following general formula (9).

  [In the formula (9), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. Multiple and may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (10), (11), and (12). ]

  As the compound represented by the general formula (9), compounds having a methyl group or an ethyl group are particularly preferable as substituents for Rb and Rc.

  The monofunctional radically polymerizable compound having a charge transporting structure represented by the above general formulas (4) and (5), particularly (9) used in the present invention has a carbon-carbon double bond opened on both sides. In order to polymerize, the main structure of the polymer does not become a terminal structure, but is incorporated in a chain polymer and crosslinked by polymerization with a radical polymerizable monomer having no charge transport structure as described above. It exists in a chain and exists in a cross-linked chain between the main chain and the main chain. This cross-linked chain was polymerized between one polymer and another intermolecular cross-linked chain between the other polymer, a portion of the main chain folded in one polymer, and a position away from it in the main chain. There are intramolecular cross-linked chains generated by cross-linking with other sites derived from the monomer. Therefore, whether it is present in the main chain or in the cross-linked chain, the triarylamine structure suspended from the chain portion is at least three arranged radially from the nitrogen atom. It has an aryl group and is bulky, but it is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group or the like, and is fixed in a state that is flexible in three-dimensional positioning. . Therefore, since these triarylamine structures can be arranged in a polymer in a space that is reasonably adjacent to each other, there is little structural distortion in the molecule, and when the surface layer of the electrophotographic photoreceptor is used, the charge is reduced. It is presumed that an intramolecular structure that is relatively free from disruption of the transport route can be adopted.

  In addition, the monofunctional radically polymerizable compound having a charge transport structure used in the present invention is important for imparting charge transport performance of a surface layer (sometimes referred to as “crosslinked surface layer”). This component is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the crosslinked surface layer. When this component is less than 20% by weight, the charge transport performance of the crosslinked surface layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appears with repeated use. On the other hand, if it exceeds 80% by weight, the content of the radically polymerizable monomer having no charge transport structure is lowered, and the crosslinking density (crosslinking density) is lowered, so that high wear resistance is not exhibited. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

(About polymerization initiator)
The surface layer of the present invention contains a cured resin having a crosslinked structure (crosslinked type cured resin), a lubricating material, and a dispersion aid, and the cured resin has a monofunctional radical polymerization having a charge transporting structure. Is a cured product of a functional compound, a radical polymerizable monomer having no charge transport structure, and a polyfunctional thiol having two or more thiol groups.
The cured resin is made into a cured product having a crosslinked structure by at least one of heating and light energy irradiation. In that case, in order to advance a crosslinking reaction efficiently, you may make a polymerization initiator contain in the coating liquid for surface layers.

That is, examples of the polymerization initiator include a thermal polymerization initiator, a photopolymerization initiator, and a mixture thereof.
Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.
These polymerization initiators may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Photopolymerization initiator, bis (cyclopentadienyl) -di-chloro-titanium, bis (cyclopentadienyl) -di-phenyl-titanium, bis (cyclopentadienyl) -bis ( , 3,4,5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium, etc. , Etc.
Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine Oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine compound, imidazole compound, and the like It is done.

Moreover, what has the said thermogravimetric or photopolymerization promotion effect can also be used individually or in combination with the said polymerization initiator. Examples of the thermogravimetric or photopolymerization promoting effect include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and (2-dimethylamino) ethyl benzoate. 4,4′-dimethylaminobenzophenone and the like, and these may be used alone or in admixture of two or more.
Content of a polymerization initiator is 0.01-40 weight part with respect to 100 weight part of compounds which have radical polymerizability, Preferably it is 0.1-30 weight part.

<Lubricating material>
As the lubricating material used in the surface layer of the present invention, any material can be used as long as it can reduce the friction between members in contact with the electrophotographic photosensitive member. And semi-solid and liquid lubricants containing the same. Examples of solid lubricants include molybdenum disulfide, organic molybdenum compounds, melamine cyanurate, boron nitride, graphite, mica, talc, fluororesin, silicone resin, polyethylene resin, polypropylene resin, nylon resin, acrylic resin, and urethane resin. A semi-solid lubricating material in which these solid lubricants are held in a thickener or a liquid lubricant added to petroleum refined products can also be used favorably. Also, the solid lubricant particles and powders can be used favorably. Among these, silicone fine particles, fluororesin fine particles, and the like are preferable, and fluororesin particles are particularly preferable in terms of stability of electric characteristics and durability of friction reduction performance as an electrophotographic photosensitive member.

(About fluororesin fine particles)
As the fluororesin fine particles used in the outermost surface layer of the photoconductor of the present invention, particles and powders having an average primary particle size in the range of 0.01 to 10 μm are preferably used. In the present invention, “fine particles” including fine particles and powders are referred to.
Examples of such fluororesin fine particles include tetrafluoroethylene resin fine particles (PTFE), perfluoroalkoxy resin fine particles, trifluorinated ethylene chloride fine resin particles, hexafluoroethylene propylene resin fine particles, vinyl fluoride resin fine particles, and fluorocarbon resin fine particles. And vinylidene chloride resin fine particles, ethylene fluoride dichloride resin fine particles, and copolymers thereof. Specifically, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene hexafluoride. Propylene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), and the like.
Only one type of lubricating material may be used, or two or more types may be used. For example, tetrafluoroethylene resin fine particles, perfluoroalkoxy resin fine particles and the like are preferably used.

The amount of the lubricating material (for example, fluororesin fine particles) added is within the range of 5 to 50% by weight with respect to the total solid content of the surface layer in order to maintain a low coefficient of friction on the surface of the photoreceptor. Is more preferable, and it is preferable that it is in the range of 10 to 40% by weight. When the blending ratio of the fluororesin fine particles is less than 5% by weight, the effect is insufficient for maintaining the low coefficient of friction, and the lubricating function cannot be sufficiently exhibited and foreign matters such as toner components cannot be removed. There is. Thereby, it may become a factor which generate | occur | produces abnormal images, such as an image blur.
In general, when the blending ratio of the fluororesin fine particles is 10% by weight or more, it may be difficult to form a surface with a smooth surface in the formation of the protective layer (surface layer) by wet coating. However, in the surface layer coating liquid containing the constituent material of the present invention, a lubricating material (for example, fluororesin fine particles) exhibits high dispersion stability, and there is no coating defect even when the blending ratio is 50% by weight. It is possible to form a smooth photoreceptor surface.
On the other hand, when the blending ratio of the fluororesin fine particles exceeds 50% by weight, the ratio of the crosslinked cured product is relatively small because the blending amount of the radical polymerizable monomer having no charge transporting structure having a high crosslinking speed is relatively small. The wear resistance may be reduced.
In the present invention, since the fluororesin fine particles exhibit high dispersion stability in the surface layer coating liquid and prevent aggregation of the particles, the entire surface layer is not unevenly distributed in specific portions of the surface layer. Since it is dispersed in, it exhibits high cleaning properties. Even in use over time, the fluororesin fine particles are exposed on the surface of the photoconductor according to the wear of the surface layer each time, so that a low friction coefficient can be maintained.

  The pulverization (agglomeration) and dispersion of the fluororesin when obtaining the fluororesin fine particles are performed by ball mill, vibration mill, sand mill, KD mill, three roll mill, pressure homogenizer, liquid collision type disperser, high pressure jet disperser, ultrasonic This can be done by dispersion or the like. In some cases, dispersibility may be further increased by combining these dispersion methods. Moreover, it is not preferable that the primary particle diameter of the fluororesin fine particles is too large or too small to satisfy the average diameter of the preferred primary particles and secondary particles of the present invention. As described above, those having an average particle diameter of 0.01 to 10 μm are preferably used.

<Dispersing aid>
The dispersion aid used in the present invention includes a function of adsorbing on the surface of the lubricating material, and a component (polyfunctional thiol, radical polymerizable compound, etc.) for forming a cured resin (cross-linked cured resin) contained in the surface layer. Any one can be used as long as it has a function of maintaining compatibility with a radically polymerizable monomer and the like and improves the dispersibility of the lubricating material.
Specific examples include polycarboxylic acid dispersion aids, urethane dispersion aids, acrylic resin dispersion aids, silicone dispersion aids, and fluorine dispersion aids. These can be selected optimally according to the lubricating material and binder component used for the surface layer, but in the present invention in which fluororesin particles can be used favorably as the lubricating material, a fluorine-based dispersion aid is used. More preferred.
As such a dispersion aid, a fluorine-based surfactant, a fluorine-based graft polymer, a fluorine-based block polymer, a coupling agent, and the like can be used.
In the conventional electrophotographic photoreceptor, the content of the dispersion aid is appropriately 1% by weight or less of the lubricating material, and if the content is higher than that, there is a side effect that stability of electric characteristics and wear resistance are lowered. However, the present invention includes a monofunctional radically polymerizable compound having a charge transporting structure excellent in electrical property stability and a radical polymerizable monomer not having a charge transporting structure excellent in abrasion resistance. The content can be set in a range not conceivable from the conventional practice.

That is, the content of the dispersion aid is preferably in the range of 2 to 20% by weight, more preferably in the range of 4 to 16% by weight, based on the total solid content of the surface layer.
When the blending ratio of the dispersion aid with respect to the total solid content of the surface layer is less than 2% by weight, the lubricating material (for example, fluororesin fine particles) easily aggregates and settles and does not exhibit good dispersibility, and a predetermined amount of fluorine. It is difficult to uniformly contain resin fine particles in the surface layer.
On the other hand, in general, when the blending ratio of the dispersion aid exceeds 20% by weight, the viscosity of the coating liquid becomes high and air bubbles are easily generated, which causes surface defects during coating. Furthermore, there is a concern that not only the productivity will be lowered but also the electrostatic characteristics will be adversely affected, such as an increase in the residual potential when the photoconductor is exposed to light. However, in the constituent material for forming the surface layer of the present invention, even if a relatively large amount of 20% by weight is added to the total solid content of the surface layer, no adverse effect on the electrostatic properties is observed. This is because the lubricating material (for example, fluororesin fine particles) has a high dispersion stability in the surface layer coating liquid and prevents aggregation of the particles. Like the fluororesin fine particles, since they exist without being unevenly distributed, it is considered that charge accumulation does not occur and excellent electrostatic characteristics can be maintained even in repeated use.

Further, as an advantage of increasing the content of the dispersion aid, there is a friction reducing effect on the cleaning member in contact with the electrophotographic photosensitive member. In other words, friction control over a long period of time could not be achieved only by controlling the lubricious material, but over a long period of time by setting the content of the dispersion aid according to the present invention in accordance with the lubricating material. Friction can be reduced. Furthermore, this effect is even more pronounced when the cleaning member is an elastic blade with a hardened tip and a vicinity of the edge of the tip, and it is possible to achieve long-term friction reduction that was impossible to achieve with the conventional technology.
The reason why such a long-term friction reducing function is manifest is not clear, but is presumed as follows. In other words, the conventional cross-linked surface layer (surface layer composed of a cross-linked resin) has a friction reducing function by dispersing a lubricating material in advance in the surface layer and supplying the lubricating material from inside the surface layer over time of use. However, in places where there is no lubricious material such as particles between dispersed lubricant materials, the friction reducing function may not be exhibited or the performance may be significantly reduced. .
On the other hand, in the present invention, by containing a large amount of a dispersion aid, the dispersion aid is also present in a place where such a friction reducing function is not sufficiently exhibited, for example, excellent in lubricity and slidability. In particular, in the fluorine-based dispersion aid, the above-described friction reducing function can be improved.
In addition, in such a surface layer having a large content of a lubricating material and a dispersion aid, there is a concern about a decrease in the crosslinking density. It is contained in the layer, whereby a sufficiently developed cross-linked structure can be constructed while suppressing a decrease in the cross-linking reaction rate, and desired wear resistance can be realized. As described above, the long-term friction reducing function can be realized for the first time by containing the constituent materials described in the present invention and a dispersion aid in an amount that cannot be considered from the conventional practice.

<Additives>
The surface layer coating solution used for forming the surface layer of the present invention includes a polyfunctional thiol having two or more functional groups, a monofunctional radical polymerizable compound having a charge transporting structure, and a charge transporting structure. It contains radically polymerizable monomers, lubricant materials, and dispersion aids that do not contain any additives, but if necessary, in addition to various solvents, various plasticizers (for the purpose of stress relaxation and adhesion improvement) and leveling agents Such additives can be contained.
As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20 parts by weight or less, preferably 10 parts by weight or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. The amount of 5% by weight or less is appropriate.

<Coating method>
When the radically polymerizable monomer having no charge transporting structure is a liquid, the surface layer coating liquid of the present invention can be applied by dispersing and dissolving other components in the liquid. Depending on the condition, it is diluted with a solvent and applied. Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatics such as benzene, toluene, and xylene, and cellosolves such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate.
These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. Coating can be performed using dip coating, spray coating, bead coating, ring coating, etc., but spray coating is the best method for forming the surface layer without eroding the photosensitive layer. is there.
When the thermal polymerization initiator generates radicals at a relatively low temperature, the production efficiency can be improved by not including the thermal polymerization initiator in the surface layer coating liquid. That is, by adjusting the thermal polymerization initiator coating liquid separately from the surface layer coating liquid and coating it separately, an increase in the viscosity of the coating liquid can be avoided. When it is necessary to dissolve or dilute the thermal polymerization initiator in a solvent, the above solvent for the surface layer coating solution can be used in the same manner.

<Method for forming surface layer>
As described above, the surface layer in the present invention includes a polyfunctional thiol having two or more functional groups, a monofunctional radically polymerizable compound having a charge transporting structure, a radically polymerizable monomer having no charge transporting structure, Using a surface layer coating solution containing at least a lubricating material and a dispersion aid, it is applied onto a photosensitive layer having a single layer structure or a multilayer structure, and at least one of heating and light energy irradiation (heating alone, It is formed by treatment with light energy irradiation alone or heating and light energy irradiation in combination.
In the present invention, such a surface layer coating solution (hereinafter sometimes abbreviated as “coating solution”) is applied onto the photosensitive layer and then cured by applying energy from the outside. As the external energy used at this time, at least one of heating and light energy irradiation is used.

(In case of heat treatment)
In the present invention, the surface layer can be cross-linked by applying heat energy from the outside after coating the surface layer coating liquid (hereinafter sometimes abbreviated as coating liquid) on the photosensitive layer. The method of applying (heating) the heat energy at this time is performed by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays, or electromagnetic waves.
The heating temperature is preferably 50 ° C. or more and 200 ° C. or less, and if it is less than 50 ° C., the reaction rate is slow and the curing reaction may not be completed completely. When the temperature is higher than 200 ° C., the curing reaction proceeds non-uniformly, and large distortion, a large number of unreacted residues, and reaction termination terminals may occur in the surface layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.
In the present invention, the chain transfer agent contains a polyfunctional thiol having two or more functional groups, and the influence of oxygen inhibition can be greatly reduced. Further, since the crosslinking reaction rate is high, the heat necessary for crosslinking can be obtained. Energy can be reduced. That is, crosslinking at a low temperature and in a short time is possible, and deterioration of the charge transporting structure due to the generated radicals can be suppressed to a minimum.
In addition, although it is possible to improve the crosslinking density by lowering the oxygen concentration during heating, in the formation of the surface layer in the present invention, the crosslinking density can be improved without reducing the oxygen concentration. Specifically, the oxygen concentration can be set in the range of 0.1 to 15% by volume.

(In the case of light energy irradiation treatment)
In the present invention, after the coating solution is applied onto the photosensitive layer, the surface layer can be crosslinked by applying light energy from the outside.
As the light energy, a light source (UV) such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc metal halide lamp or the like may be used. It is preferable to select in consideration of the polymerizable monomer, the compound having a charge transporting structure, the photopolymerization initiator used in combination, and the absorption characteristics of the sensitizing dye. The emission intensity of light source used, depending on the formulation of the photosensitive layer forming material, typically a wavelength of 365nm as a reference in illuminance of 50mW ^/ cm ² ~2000mW ^/ cm 2 may be irradiated with the irradiation object. The irradiation time is appropriately selected depending on the surface layer prescription, but it may be irradiated for 30 seconds to 240 seconds. Moreover, when the illuminance measurement in the vicinity of the maximum emission wavelength is possible, it is more preferable to expose in the illuminance range. When the illuminance is low, the time required for curing increases, which is not preferable from the viewpoint of productivity. On the other hand, when the illuminance is high, curing shrinkage is likely to occur, and the surface may have a skin-like defect or crack, or may peel at the interface with the adjacent layer.

During UV irradiation, the temperature of the photoreceptor surface layer rises due to the influence of heat rays generated from the light source. If the surface temperature of the photoconductor rises too much, curing shrinkage of the surface layer is likely to occur, and low molecular components contained in the adjacent layer migrate to the surface layer, resulting in inhibition of curing or as an electrophotographic photoconductor. This is not preferable, for example, because the electrical characteristics are degraded. In addition, when the surface temperature of the photoconductor surface is too high, the lubricating material as the constituent material of the present invention causes agglomeration of particles such as a lubricating material (for example, fluororesin fine particles or particles) due to heat, and the photoconductor surface. Protruding agglomerates are generated on the surface, causing coating defects.
A coating defect is not preferable in that it not only causes a reduction in cleaning performance and an abnormal image, but also reduces the dispersibility of the lubricating material. Therefore, the photoreceptor surface temperature during UV irradiation is 100 ° C. or lower, preferably 80 ° C. or lower. As a cooling method, it is possible to use a cooling agent sealed inside the photoconductor, cooling with a gas or liquid inside the photoconductor, or the like.
The thickness of the surface layer is preferably 1.0 to 20.0 μm or less, and preferably 2.0 to 15.0 μm, from the viewpoint of protecting the photosensitive layer. If the surface layer is thin, coating film defects are likely to occur, and the photosensitive layer cannot be protected from mechanical wear due to the contact member to the photosensitive member or proximity discharge due to a charger, etc. The film surface may become distorted because it is less likely to occur. On the other hand, if the surface layer is thick, the entire photoreceptor layer becomes thick, and cracks and film peeling tend to occur, and the surface shape becomes difficult to control due to the occurrence of coating film defects, resulting in a significant increase in residual potential. Or the reproducibility of the image due to the diffusion of charges is not preferable.

As described above, the photoreceptor of the present invention is a laminate having at least a photosensitive layer and a surface layer in this order on a conductive support, and the photosensitive layer has a charge generation function and a charge transport function. A single layer structure or a multilayer structure may be used.
Here, other layers may be provided as necessary. For example, an adhesive layer may be provided between the two layers as necessary for the purpose of preventing delamination due to poor adhesion between the surface layer and the photosensitive layer (single layer or laminated structure).
(Adhesive layer)
As the adhesive layer, a radical polymerizable monomer having no charge transport structure may be used, or a non-crosslinked polymer compound may be used. Non-crosslinked polymer compounds include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like, but are not limited thereto. In addition, the radical polymerizable monomer and the non-crosslinked polymer compound may be used either alone or as a mixture of two or more. Furthermore, a radical polymerizable monomer and a non-crosslinked polymer compound may be used in combination as long as sufficient adhesiveness is obtained. Of course, the charge transport material described in this specification may be used or may be used in combination. Moreover, if it aims at improving adhesiveness, you may use an additive suitably.
The adhesive layer is formed by applying a coating solution prepared by dissolving or dispersing a compound formulated in a prescribed formulation in a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane by dip coating, spray coating, bead coating, or ring coating. it can. The thickness of the adhesive layer is suitably about 0.1 to 5 μm, preferably 0.1 to 3 μm is most suitable.

[Conductive support]
As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium is deposited or sputtered to form film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube that has been subjected to surface treatment such as cutting, superfinishing, or polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

In addition, the conductive support dispersed in an appropriate binder resin (binder resin) and coated on the support can also be used as the conductive support of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used simultaneously includes polystyrene, styrene acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Vinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin , A thermoplastic resin such as a urethane resin, a phenol resin, and an alkyd resin, a thermally crosslinkable resin, or a photocrosslinkable resin. Such a conductive layer can be provided by dispersing and applying these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Further, a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support of the present invention.

(Photosensitive layer)
Next, the photosensitive layer will be described. As described above, the photosensitive layer may have a function separation type laminated structure or a single layer structure. In the case of a laminated structure, the photosensitive layer is generally formed from a charge generation layer and a charge transport layer. In the case of a single layer structure, the photosensitive layer is a layer having both a charge generation function and a charge transport function. Hereinafter, each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described.

<When the photosensitive layer has a laminated structure>
Since the charge generation function and the charge transport function are provided by independent layers, the photosensitive layer layer has a structure in which at least a charge generation layer and a charge transport layer are stacked on a conductive support. The order of stacking is not particularly limited, but many charge generation materials have poor chemical stability, and the charge generation efficiency decreases when exposed to acidic gases such as discharge products around the charger in the electrophotographic imaging process. Cause. For this reason, a charge transport layer is preferably laminated on the charge generation layer.

(Charge generation layer)
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triarylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments Indigoid pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

  The binder resin (binder resin) used in the charge generation layer as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly- N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, etc. It is done. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.

Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed. In addition, in order to provide the charge generation layer by the latter casting method, the inorganic or organic charge generation material described above, together with a binder resin, if necessary, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. It can be formed by dispersing with a ball mill, attritor, sand mill, bead mill or the like using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc., and applying the solution after appropriately diluting the dispersion. Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

(About charge transport layer)
The charge transport layer is a layer having a charge transport function, and is mainly a charge transport material and a binder resin (binder resin). Examples of the charge transport material include a hole transport material and an electron transport material.
Examples of the charge transport material include a hole transport material and an electron transport material as described in the section of the surface layer. As the charge transporting material used for the surface layer, compounds having the above-described charge transporting structure and having no polymerizable functional group can be mainly used. In addition, a charge transport material having a polymerizable functional group may be used in combination for improving the adhesion between the surface layer and the photosensitive layer. As the charge transporting material used for the charge transporting layer, the above-mentioned compound having no polymerizable functional group may be used alone, or a compound having no polymerizable functional group and / or a compound having it may be used in combination.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Examples thereof include thermoplastic or thermosetting resins such as phenol resins and alkyd resins.

In addition, as a binder resin, a polymeric charge transport material having a charge transport function, for example, polycarbonate, polyester, polyurethane, polyether, and polyamine having an arylamine skeleton, a benzidine skeleton, a hydrazone skeleton, a carbazole skeleton, a stilbene skeleton, a pyrazoline skeleton, or the like. Polymer materials such as siloxane and acrylic resins, polymer materials having a polysilane skeleton, and the like can be used and are useful.
The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it may be used alone or in combination with a binder resin.

  As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used alone or in combination of two or more.

  If necessary, a plasticizer and a leveling agent can be added. As the plasticizer used for the charge transport layer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 to 100 parts by weight of the binder resin. About 30 parts by weight is appropriate. Examples of leveling agents that can be used in the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. About 0 to 1 part by weight is appropriate for the part by weight.

  The thickness of the charge transport layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of resolution and responsiveness. Regarding the lower limit, although it differs depending on the system to be used (particularly the charging potential), it is preferably 5 μm or more.

<When the photosensitive layer is a single layer>
A photosensitive layer having a single layer structure is a layer having both a charge generation function and a charge transport function. The photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in a suitable solvent, and applying and drying them. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. The photosensitive layer is formed by dip coating, spray coating, bead coating, ring coating with a charge generating material, a binder resin and a charge transport material dispersed in a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a coat. The film thickness of the photosensitive layer is suitably about 5 to 25 μm.

[Undercoat layer]
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes
Al ₂ O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), and inorganic substances such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ were provided by a vacuum thin film manufacturing method Goods can also be used well. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

<Addition of antioxidant to each layer>
In the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, in particular, a surface layer, an adhesive layer, a photosensitive layer (in the case of a laminated structure, at least a charge generation layer, a charge layer) An antioxidant may be added to each layer such as the transport layer), the undercoat layer, and the intermediate layer. The following are mentioned as antioxidant which can be used for this invention.

(Phenolic compounds)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [meth -3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyl Rick acid] cricol ester, tocopherols and the like.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-t-butyl-p-phenylenediamine and the like.

(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.

(Organic sulfur compounds)
Dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate, and the like.

(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

Each of the above compounds is known as an antioxidant such as rubber, plastic, and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in this invention is 0.01-10 weight part with respect to the total weight of the layer to add.

<Image Forming Method, Image Forming Apparatus, and Process Cartridge for Image Forming Apparatus>
Next, an image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus according to the present invention will be described in detail with reference to the drawings.
An image forming apparatus of the present invention includes the electrophotographic photosensitive member of the present invention, a charging unit, an exposure unit, a developing unit, and a transfer unit.
The image forming method of the present invention is characterized in that at least charging, image exposure, development and transfer are repeated using the electrophotographic photosensitive member of the present invention.
The process cartridge of the present invention comprises at least one of an electrostatic latent image forming unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, and the electrophotographic photosensitive member of the present invention.
The image forming apparatus of the present invention is an electrophotographic photosensitive member having a surface layer (abbreviated as “crosslinked surface layer”) containing a cured resin having a crosslinked structure in the present invention, a lubricating material, and a dispersion aid. For example, after at least charging, image exposure, and development processes are performed on the photosensitive member, the process of transferring the toner image onto the image holding member (transfer paper), fixing, and cleaning the surface of the photosensitive member can be performed. It is what. In some cases, an image forming apparatus that directly transfers an electrostatic latent image to a transfer member and develops it does not necessarily include means for enabling the above-described process provided on the photosensitive member.

Here, one embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.
FIG. 5 is a schematic diagram illustrating a configuration example of an image forming apparatus according to the present invention. In FIG. 5, the photoreceptor (1) has at least a photosensitive layer and a surface layer in order on a conductive support, and the surface layer has a polyfunctional thiol having two or more functional groups and a charge transporting structure. It contains a cured resin having a crosslinked structure that is a cured product of a monofunctional radically polymerizable compound and a radically polymerizable monomer having no charge transporting structure, a lubricating material, and a dispersion aid.
In FIG. 54, a charging charger (3) is used as means for charging the photosensitive member on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known method can be used.

  Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.

  Next, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto a transfer body (transfer paper) (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.

  Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

  Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination.

Next, a neutralizing unit is used for the purpose of removing the latent image on the photoreceptor as required. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.
In FIG. 5, reference numeral 4 denotes an eraser, and reference numeral 8 denotes a registration roller.
The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.

  The present invention is an image forming apparatus using the photoreceptor according to the present invention for the above-described image forming means. The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of a process cartridge for an image forming apparatus is shown in the schematic diagram of FIG.

  The process cartridge for an image forming apparatus is a device that has a built-in photoconductor, and further includes at least one of a charging unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit, and is detachable from the image forming apparatus main body ( Parts). FIG. 6 shows an example of a process cartridge according to the present invention.

  Referring to the image forming process by the apparatus illustrated in FIG. 6, the surface of the photoconductor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106), and printed. Be out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

In addition, a protective substance may be applied to the surface of the electrophotographic photosensitive member for the purpose of improving the cleaning property by reducing the surface energy of the electrophotographic photosensitive member and protecting it from electrical and mechanical hazards. It is a highly durable cross-linked surface layer containing a lubricating material and a dispersion aid in the surface layer, and high-quality image output over a long period of time is possible without using such a protective substance.
In the present invention, as the above-described cleaning blade, an elastic blade having a hardened portion near the tip ridge line can also be used favorably. As disclosed in Japanese Patent Application Laid-Open No. 2010-113133, the surface of an elastic blade is coated with an ultraviolet curable resin, and a surface layer is formed by photocrosslinking, or disclosed in Japanese Patent Application Laid-Open No. 2013-218277. As described above, it is possible to increase the hardness of the vicinity of the ridge line of the elastic blade by a method of photocrosslinking after impregnating the elastic blade with an ultraviolet curable resin.
Thus, the elastic blade having a high hardness in the vicinity of the tip ridge line is suitable for cleaning polymerized toner capable of forming a high-resolution image by reducing the diameter and increasing the circular shape. The polymerized toner can be produced by suspension polymerization, emulsion polymerization, or dispersion polymerization, and in particular, by using a toner having a circularity of 0.97 or more and a volume average particle size of 5.5 (μm) or less, a higher resolution can be obtained. An image can be formed.
Such a polymerized toner has a problem that due to its shape, the cleaning property from the surface of the electrophotographic photosensitive member may not be sufficient, and a streaky abnormal image is generated due to poor cleaning. This can be solved by increasing the contact pressure of the cleaning blade to the electrophotographic photosensitive member, but since the wear of the cleaning blade and the electrophotographic photosensitive member is accelerated, the lifetime of the entire system has not been extended. Furthermore, since the frictional force between the cleaning blade and the electrophotographic photosensitive member becomes large, the tip of the cleaning blade turns over. As an initial problem, abnormal noise and vibration, and as a long-term problem, streaky abnormalities due to missing cleaning blade tip There were problems such as image generation. On the other hand, the surface layer of the electrophotographic photosensitive member of the present invention contains a large amount of a lubricating material and a dispersion aid that express low friction characteristics while sufficiently improving the crosslinking density, and in the vicinity of the above-mentioned leading edge line. However, even in a system using an elastic blade with a high hardness and a polymerized toner, stable high-resolution image quality can be formed over a long period of time.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples at all.

  First, examples in which the surface layer of the electrophotographic photosensitive member is formed by light energy irradiation will be described in Examples 1 to 15 below. Comparative Examples 1 to 19 will be described including an example of forming by heating in addition to an example of forming by light energy irradiation.

[Example 1]
<< Method for producing photoconductor >>
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and an 18 μm charge transport layer were formed.
[Coating liquid for undercoat layer]
・ Alkyd resin 6 parts by weight (Beckosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 4 parts by weight (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide 40 parts by weight ・ Methyl ethyl ketone 50 parts by weight [Coating liquid for charge generation layer]
-2.5 parts by weight of a bisazo pigment represented by the following structural formula (13)

Polyvinyl butyral (XYHL, manufactured by UCC) 0.5 part by weight Cyclohexanone 200 part by weight Methyl ethyl ketone 80 part by weight

[Coating liquid for charge transport layer]
-10 parts by weight of bisphenol Z polycarbonate (Panlite TS-2050, manufactured by Teijin Chemicals)
-7 parts by weight of a low molecular charge transport material represented by the following structural formula (14)

Tetrahydrofuran 100 parts by weight 1% silicone oil tetrahydrofuran solution 1 part by weight (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

  Next, a surface layer coating solution having the following composition was applied onto the laminate comprising the conductive support / undercoat layer / charge generation layer / charge transport layer, and then a UV lamp system manufactured by USHIO (USHIO: metal halide) The surface layer was cross-linked by light irradiation under the conditions of illuminance: 450 mW / cm 2 and irradiation time: 90 seconds while rotating the drum using a lamp to obtain a 5 μm hardened surface film. Thereafter, drying was performed at 130 ° C. for 30 minutes to obtain an electrophotographic photosensitive member 1 composed of a conductive support / undercoat layer / charge generation layer / charge transport layer / surface layer.

[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 27.4 parts by weight Compound (D1655) represented by the following structural formula (15)

-37.0 parts by weight of radically polymerizable monomer having no charge transport structure pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
・ Multifunctional thiol having 2 or more functional groups 4.1 parts by weight pentaerythritol tetrakis (3-mercaptobutyrate)
(Karenzu MT PE1, Showa Denko)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 8.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 3.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

  The dispersion of tetrafluoroethylene resin fine particles is a 30 ml sample bottle containing 40 g of 0.1 mm zirconia ball media, 11.4 g of tetrahydrofuran, 0.6 g of tetrafluoroethylene resin fine particles and a fluorosurfactant. 0.24 g was added, and a vibration shaker was used to vibrate for 1 hour at a dispersion strength of 1000 rpm, and the mill base after ultrasonic vibration was used. The average particle size of the dispersion was 0.4 μm.

[Example 2]
An electrophotographic photosensitive member 2 was produced in the same manner except that the polyfunctional thiol having two or more functional groups used in the surface layer coating solution of Example 1 was changed to the following.
[Coating liquid for surface layer]
-Polyfunctional thiol having 2 or more functional groups 4.1 parts by weight 1,4-bis (3-mercaptobutyryloxy) butane (Karenz MT BD1, manufactured by Showa Denko KK)

[Example 3]
An electrophotographic photoreceptor 3 was produced in the same manner except that the polyfunctional thiol having two or more functional groups used in the surface layer coating solution of Example 1 was changed to the following.
[Coating liquid for surface layer]
-Polyfunctional thiol having 2 or more functional groups 4.1 parts by weight 1,3,5-tris (3-mercaptobutyryloxyethyl)
1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (Karenz MT NR1, manufactured by Showa Denko KK)

[Example 4]
An electrophotographic photoreceptor 4 was produced in the same manner except that the polyfunctional thiol having two or more functional groups used in the surface layer coating solution of Example 1 was changed to the following.
[Coating liquid for surface layer]
-Polyfunctional thiol having 2 or more functional groups 4.1 parts by weight trimethylolpropane tris 3-mercaptobutyrate)
(TPMB, Showa Denko)

[Example 5]
An electrophotographic photoreceptor 5 was produced in the same manner except that the polyfunctional thiol having two or more functional groups used in the surface layer coating solution of Example 1 was changed to the following.
[Coating liquid for surface layer]
-Polyfunctional thiol having 2 or more functional groups 4.1 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)

[Example 6]
An electrophotographic photosensitive member 6 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 28.2 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 38.1 parts by weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 4.2 parts by weight Trimethylolethanetris (3-mercaptobutyrate)
(TEMB, Showa Denko)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 6.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 3.5 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, manufactured by Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 7]
An electrophotographic photoreceptor 7 was produced in the same manner except that the lubricating fine particles used in the surface layer coating solution of Example 5 were changed to the following.
[Coating liquid for surface layer]
-Lubricating material 8.0 parts by weight Perfluoroalkoxy resin fine particles (Mitsui / DuPont Fluorochemicals, Teflon (registered trademark) MPE-056)

  The dispersion of the perfluoroalkoxy resin fine particles was placed in a 30 ml sample bottle with 40 g of zirconia ball media having a diameter of 0.1 mm, 11.4 g of tetrahydrofuran, 0.6 g of perfluoroalkoxy resin fine particles, and a fluorosurfactant in an amount of 0. 24 g was added, and a vibration shaker was used to vibrate for 1 hour at a dispersion strength of 1000 rpm, and the mill base after ultrasonic vibration was used. The average particle size of the dispersion was 0.4 μm.

[Example 8]
An electrophotographic photoreceptor 8 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable compound having a charge transporting structure 35.4 parts by weight Compound represented by the structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transporting structure 47.8 Part by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 5.3 parts by weight Trimethylolethanetris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 5.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 2.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 4.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 9]
An electrophotographic photoreceptor 9 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 32.8 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 44.2 Part by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 4.9 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 10.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 4.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 4.1 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, manufactured by Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 10]
An electrophotographic photoreceptor 10 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 29.7 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 40.1 Part by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 4.5 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 10.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 2.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 3.7 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 11]
An electrophotographic photoreceptor 11 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable compound having a charge transporting structure 16.8 parts by weight Compound represented by structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transporting structure 22.6 Part by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Polyfunctional thiol having 2 or more functional groups 2.5 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material: 40.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 16.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 2.1 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 12]
An electrophotographic photoreceptor 12 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 18.3 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 24.7 parts by weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Polyfunctional thiol having 2 or more functional groups 2.7 parts by weight Trimethylolethanetris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material: 40.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 12.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 2.3 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 13]
An electrophotographic photoreceptor 13 was produced in the same manner except that the composition of the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable compound having a charge transporting structure 11.4 parts by weight Compound represented by structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transporting structure 15.4 Part by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Polyfunctional thiol having 2 or more functional groups 1.7 parts by weight Trimethylol ethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 50.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 20.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
-Photopolymerization initiator 1.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 14]
An electrophotographic photoreceptor 14 was prepared in the same manner except that the radical polymerizable monomer having no charge transporting structure used in the surface layer coating solution of Example 5 was changed to the following.
[Coating liquid for surface layer]
-Radical polymerizable monomer having no charge transporting structure 37.0 parts by weight Ditrimethylolpropane tetraacrylate (SR355, manufactured by Sartomer)

[Example 15]
An electrophotographic photoreceptor 15 was produced in the same manner except that the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 29.7 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 40.1 weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 4.5 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
・ Dispersing aid 2.0 parts by weight Fluorosurfactant (Aron GF400, manufactured by Toagosei Co., Ltd.)
Photopolymerization initiator 3.7 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

  The dispersion of tetrafluoroethylene resin fine particles is a 30 ml sample bottle containing 40 g of 0.1 mm zirconia ball media, 11.4 g of tetrahydrofuran, 0.6 g of tetrafluoroethylene resin fine particles and a fluorosurfactant. 0.06 g was added, and a vibration shaker was used to vibrate for 2 hours at a dispersion strength of 1000 rpm, and the mill base after ultrasonic vibration was used. The average particle size of the dispersion was 0.4 μm.

[Comparative Example 1]
An electrophotographic photosensitive member 16 was produced in the same manner except that the surface layer coating solution of Example 1 had the following composition.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 31.7 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transporting structure 31.7 parts by weight Part trimethylolpropane triacrylate (TMPTA, manufactured by Sartomer)
-Thiol compound having one or more functional groups 3.3 parts by weight n-butyl-3-mercaptopropionate-3.3 parts by weight photopolymerization initiator 2-hydroxy-1- {4- [4- (2- Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one (Irgacure-127, manufactured by Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 2]
An electrophotographic photoreceptor 17 was produced in the same manner except that the radical polymerizable monomer having no charge transporting structure in the surface layer coating solution of Comparative Example 1 was changed to the following.
[Coating liquid for surface layer]
-Radical polymerizable monomer having no charge transporting structure 31.7 parts by weight Compound represented by the following structural formula (16) (DPCA-120, manufactured by Nippon Kayaku Co., Ltd.)

[Comparative Example 3]
An electrophotographic photoreceptor 18 was produced in the same manner except that the thiol compound having one or more functional groups in the surface layer coating solution of Comparative Example 1 was changed to the following.
[Coating liquid for surface layer]
-Multifunctional thiol having 2 or more functional groups 3.3 parts by weight trimethylolpropane tris 3-mercaptobutyrate)
(TPMB, Showa Denko)

[Comparative Example 4]
An electrophotographic photoreceptor 19 was produced in the same manner except that the thiol compound having one or more functional groups in the surface layer coating solution of Comparative Example 1 was changed to the following.
[Coating liquid for surface layer]
・ Multifunctional thiol having 2 or more functional groups 3.3 parts by weight pentaerythritol tetrakis (3-mercaptobutyrate)
(Karenzu MT PE1, Showa Denko)

[Comparative Example 5]
The composition of the surface layer coating solution of Example 1 was changed as follows. In addition, after coating the surface layer coating liquid having the following composition on the laminate comprising the conductive support / undercoat layer / charge generation layer / charge transport layer, a nitrogen dryer having an oxygen concentration meter, In a state where the oxygen concentration was 200 ppm or less, a curing reaction was performed at a temperature of 160 ° C. for 60 minutes to form a surface layer of 5 μm, and the electrophotographic photosensitive member 20 was produced.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 100.0 parts by weight Compound represented by the following structural formula (17)

-Polyfunctional thiol having 2 or more functional groups 30.0 parts by weight 1,4-bis (3-mercaptobutyryloxy) butane (Karenz MT BD1, manufactured by Showa Denko KK)
-Thermal polymerization initiator 6.0 parts by weight 2,2′-azobis (2-methylbutyronitrile) (V59, manufactured by Wako Pure Chemical Industries, Ltd.)
Cyclopentyl methyl ether / toluene (mass ratio 50:50) 315 parts by weight

[Comparative Example 6]
An electrophotographic photoreceptor 21 was produced in the same manner except that the surface layer coating solution of Comparative Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 100.0 parts by weight Compound represented by structural formula (17) used in Comparative Example 5-Compound having a charge transporting structure 25.0 parts by weight N, N '-Diphenyl-N, N'-bis (3-methylphenyl)-[1,1'] biphenyl-4,4'-diamine ・ Multifunctional thiol having 2 or more functional groups 50.0 parts by weight 1,4 -Bis (3-mercaptobutyryloxy) butane (Karenz MT BD1, manufactured by Showa Denko KK)
-Thermal polymerization initiator 6.0 parts by weight (VE73, manufactured by Wako Pure Chemical Industries, Ltd.)
Cyclopentyl methyl ether / toluene (mass ratio 50:50) 315 parts by weight

[Comparative Example 7]
An electrophotographic photoreceptor 21 was produced in the same manner except that the surface layer coating solution of Comparative Example 5 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transporting structure 100.0 parts by weight Compound represented by structural formula (17) used in Comparative Example 5-Compound having a charge transporting structure 25.0 parts by weight N, N '-Diphenyl-N, N'-bis (3-methylphenyl)-[1,1'] biphenyl-4,4'-diamine ・ Radical polymerizable monomer having no charge transport structure 25.0 parts by weight Tri Methylolpropane triacrylate (TMPTA, manufactured by Sartomer)
-Polyfunctional thiol having 2 or more functional groups 50.0 parts by weight 1,4-bis (3-mercaptobutyryloxy) butane (Karenz MT BD1, manufactured by Showa Denko KK)
-Thermal polymerization initiator 6.0 parts by weight (VE73, manufactured by Wako Pure Chemical Industries, Ltd.)
Cyclopentyl methyl ether / toluene (mass ratio 50:50) 315 parts by weight

[Comparative Example 8]
An electrophotographic photosensitive member 22 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
• 47.6 parts by weight of a monofunctional radically polymerizable compound having a charge transporting structure • Compound represented by the structural formula (15) used in Example 1 • 47.6 parts by weight of a radically polymerizable monomer having no charge transporting structure Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
Photopolymerization initiator 4.8 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 9]
An electrophotographic photosensitive member 24 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable monomer having a charge transport structure 34.3 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transport structure 34.3 parts by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
Photopolymerization initiator 3.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 8.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 10]
An electrophotographic photosensitive member 25 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable monomer having a charge transport structure 38.1 parts by weight Compound represented by the structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transport structure 51.4 parts by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 5.7 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
Photopolymerization initiator 4.8 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 11]
An electrophotographic photosensitive member 26 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transport structure 27.4 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transport structure 37.0 parts by weight Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Thiol compound having one functional group 4.1 parts by weight 2-mercaptobenzothiazole (manufactured by Tokyo Chemical Industry Co., Ltd.)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 8.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 3.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Example 12]
An electrophotographic photoreceptor 27 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
-Bifunctional radically polymerizable compound having a charge transport structure 27.4 parts by weight Compound represented by the following structural formula (18)

-37.0 parts by weight of a radically polymerizable monomer having no charge transporting structure Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Polyfunctional thiol having 2 or more functional groups 4.1 parts by weight Trimethylolethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid [Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)] 8.0 parts by weight-Photopolymerization initiator 3.4 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty) (Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 13]
An electrophotographic photosensitive member 28 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable compound having a charge transport structure 36.2 parts by weight Compound represented by the structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transport structure 48.9 weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
-Multifunctional thiol having 2 or more functional groups 5.4 parts by weight Trimethylol ethane tris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 4.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 1.0 part by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
-Photopolymerization initiator 4.5 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 14]
An electrophotographic photoreceptor 29 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transport structure 8.8 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transport structure 11.8 weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
・ Multifunctional thiol having 2 or more functional groups 1.3 parts by weight Trimethylolethanetris (3-mercaptobutyrate)
(TEMB, Showa Denko)
・ Lubricant material 55.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 22.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 1.1 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, manufactured by Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 15]
An electrophotographic photoreceptor 30 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
-Monofunctional radically polymerizable compound having a charge transport structure 33.9 parts by weight Compound represented by the structural formula (15) used in Example 1-45.8 parts by weight of a radically polymerizable monomer having no charge transport structure Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
・ Multifunctional thiol having 2 or more functional groups 5.1 parts by weight Pentaerythritol tetrakis (3-mercaptobutyrate)
(Karenzu MT PE1, Showa Denko)
・ Lubricant material 10.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries)
-Dispersing aid 22.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
Photopolymerization initiator 1.0 part by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 16]
An electrophotographic photoreceptor 31 was produced in the same manner except that the blending amounts of the lubricating material and the dispersion aid in the surface layer coating liquid of Example 1 were changed as follows.
[Coating liquid for surface layer]
-Monofunctional radical polymerizable compound having a charge transport structure 9.5 parts by weight Compound represented by the structural formula (15) used in Example 1-Radical polymerizable monomer having no charge transport structure 12.9 weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
・ Polyfunctional thiol with 2 or more functional groups 1.4 parts by weight pentaerythritol tetrakis (3-mercaptobutyrate)
(Karenzu MT PE1, Showa Denko)
・ Lubricant material 50.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
-Dispersing aid 25.0 parts by weight Fluorosurfactant (Modiper F206, manufactured by NOF Corporation)
-Photopolymerization initiator 1.2 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 17]
An electrophotographic photosensitive member 32 was produced in the same manner except that the surface layer coating solution of Example 1 was changed as follows.
[Coating liquid for surface layer]
Monofunctional radically polymerizable compound having a charge transport structure 30.5 parts by weight Compound represented by the structural formula (15) used in Example 1 Radical polymerizable monomer having no charge transport structure 41.1 weight Part Pentaerythritol tetraacrylate (SR295, manufactured by Sartomer)
・ Multifunctional thiol having 2 or more functional groups 4.6 parts by weight Pentaerythritol tetrakis (3-mercaptobutyrate)
(Karenzu MT PE1, Showa Denko)
Lubricating material 20.0 parts by weight Tetrafluoroethylene resin fine particles (Lublon L2, manufactured by Daikin Industries, Ltd.)
Photopolymerization initiator 3.8 parts by weight 1-hydroxycyclohexyl phenyl ketone (Irgacure-184, Ciba Specialty Chemicals)
・ 400 parts by weight of tetrahydrofuran

[Comparative Example 18]
An electrophotographic photoreceptor 33 was produced in the same manner except that the monofunctional radically polymerizable compound having a charge transporting structure in the surface layer coating solution of Example 5 was changed as follows.
[Coating liquid for surface layer]
Compound having charge transporting structure 27.4 parts by weight Compound represented by the following structural formula (19)

[Comparative Example 19]
An electrophotographic photoreceptor 34 was prepared in the same manner except that the radical polymerizable monomer having no charge transporting structure in the surface layer coating liquid of Example 5 was changed as follows.
[Coating liquid for surface layer]
・ Binder resin 37.0 parts by weight Bisphenol Z-type polycarbonate

  The materials used for preparing the surface layers of the electrophotographic photoreceptors 1 to 34 obtained in Examples 1 to 15 and Comparative Examples 1 to 19 are summarized in the following Table 1 (Examples) and Table 2 (Comparative Examples). Show. The contents of the lubricating material and the dispersion aid are shown as values converted to weight percent of each component with respect to the total solid content of the surface layer.

Next, production examples of the polymerized toner used in this example are shown.
Toner production example 1
(1) Preparation of monomer composition A monomer composition was prepared by dispersing and mixing a polymerizable monomer mixture having the following formulation for 24 hours using a ball mill.
[Prescription]
Styrene monomer 70 parts by weight n-butyl methacrylate 30 parts by weight Polystyrene 5 parts by weight 3,5-di-tert-butylsalicylic acid zinc salt 2 parts by weight Carbon black 6 parts by weight

(2) Granulation, polymerization 2% polyvinyl alcohol in a flask equipped with a stirrer, thermometer, inert gas introduction tube and a porous glass tube with a pore diameter of 110,000 kg, a pore volume of 0.42 cc / g, 10φ × 50 mm 400 ml of the aqueous solution was taken and stirred at room temperature while feeding nitrogen gas, and oxygen in the reaction vessel was replaced with nitrogen.
Next, 1.56 g of azobisisobutylnitrile was added to 113 g of the monomer composition of (1), dissolved by stirring, passed through a porous glass tube using a pump, added into an aqueous polyvinyl alcohol solution, and the addition was completed. A mixture of polyvinyl alcohol and the monomer composition was circulated at a rate of about 120 ml / min for 2 hours using the pump and the porous glass tube, and then the internal temperature was set to 70 ° C. and polymerized for 8 hours.
After cooling to room temperature and allowing to stand overnight, the supernatant was removed, water was added, the mixture was stirred for 1 hour, filtered and dried to obtain a toner. When the particle diameter of this toner was measured with a Coulter counter, the average particle diameter was 8.5 μm, and the particles in the range of 5 to 10 μm were 95% of the total, and the particle size distribution was extremely narrow.

Evaluation Example 1
The suspension containing the toner particles obtained in Toner Production Example 1 is passed through an imaging unit detection zone on a flat plate, the particle image is optically detected by a CCD camera, and the perimeter of an equivalent circle having the same projected area is obtained. The average circularity, which is a value obtained by dividing by the perimeter of real particles, was evaluated. This value can be measured as an average circularity by a flow type particle image analyzer FPIA-2000. As a specific measurement method, as a dispersant in 100 to 150 ml of water from which impure solids have been removed in advance. A surfactant, preferably alkylbenzene sulfonate, is added in an amount of 0.1 to 0.5 ml, and a sample to be measured is further added in an amount of about 0.1 to 0.5 g. It is obtained by performing dispersion treatment for ˜3 minutes and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. As a result of the examination so far, it has been found that a toner having 0.960 or more is effective for forming a high-definition image having a reproducibility with an appropriate density. 980 to 1.000. The circularity of the toner prepared in Toner Production Example 1 was 0.98.

  Using the electrophotographic photosensitive members 1 to 34 of Examples 1 to 15 and Comparative Examples 1 to 19 produced as described above and the toner produced in Production Example 1, the following evaluation was performed.

Evaluation example 2 (surface observation)
About the surface of the obtained electrophotographic photoreceptors 1 to 36, arbitrary 10 points were observed using a confocal laser microscope (OPTELICS H1200, manufactured by Lasertec Corporation) (magnification 100 times). At that time, ranking was performed according to the observed degree of agglomeration of the surface layer. The results are shown in Table 3.
Evaluation criteria are as follows.
Rank 3: No coating defects due to aggregates or the like are observed.
Rank 2: There are less than 10 coating defects due to aggregates and the like.
Rank 1: There are 10 or more coating defects due to aggregates or the like.

From the results shown in Table 3, the photoreceptors 1 to 15 satisfying the claims of the present invention provide an extremely smooth surface layer in which no protrusion due to aggregates or the like is observed on the photoreceptor surface even when a large amount of fluororesin fine particles are contained. I found out. However, the surface properties of the photoconductor 10 with a small amount of dispersion aid added to the fluororesin fine particles and the photoconductor 13 with a large amount of fluororesin fine particles added were partly deteriorated. On the other hand, it is considered that the photoreceptors 24 and 26 have a surface layer with a large number of surface defects because the dispersibility of the fluororesin fine particles in the coating solution is lowered.
Further, in the photoreceptors 24, 31 and 32 in which the addition amount of the fluororesin fine particles or the addition amount of the dispersion aid exceeds the specified amount of the present invention, the dispersion stability of the fluororesin fine particles is lowered, so that there are many surface defects. It seems to have become. Similarly, it is considered that the photoreceptor 32 to which no dispersion aid is added is also aggregated because the fluororesin fine particles are difficult to disperse. The photoreceptors 35 and 36 have a surface layer containing fluororesin fine particles cross-linked by thermal energy, and it is difficult to suppress the aggregation action of the fluororesin fine particles because the temperature of the surface layer is increased during the cross-linking. It is presumed that a surface layer having many surface defects was obtained.

Evaluation example 3 (surface friction coefficient)
About the obtained electrophotographic photoreceptors 1-34, the surface friction coefficient was evaluated using the Euler belt system. As used herein, the belt is medium-quality high-quality paper, and is stretched around the circumference of the photoconductor, as shown in FIG. Apply a load of 100 g, install a force gauge (spring balance) on the other side, observe the movement of the belt while gradually pulling the force gauge, and read the load at the time when the movement starts, and use the following formula (1) To calculate. In the equation, μ represents a friction coefficient, F represents a tensile force, and W represents a load.
μ = 2 / π × ln (F / W) (1)
In formula (1), W = 100 g.
In FIG. 7, reference numeral 20 denotes a force gauge (spring balance), 21 denotes a belt, 22 denotes a load, and 23 denotes a sample.
In FIG. 7, a load: 100 g weight, belt: Type 6200 / T eye / A4 paper / 30 mm width (cut in the direction of the gap), and two double clips are used. Also,

Evaluation Example 4 (Durability)
The obtained electrophotographic photoreceptors 1 to 34 are mounted on a Ricoh imagioColor 5100 remodeling machine (with the lubricant application means removed), and a total of 150,000 sheets are continuously printed. The cleaning property of the image after sheet printing was evaluated. Further, the light portion potential at the initial stage and after printing 150,000 sheets was measured. Furthermore, the amount of wear was evaluated from the difference in film thickness at the initial stage and after printing 150,000 sheets.
Tables 4 and 5 show the evaluation results of the wear amount and the surface friction coefficient.

From the results shown in Tables 4 and 5, the photoreceptors of Examples 1 to 15 satisfying the claims of the present invention have little increase in the bright part potential even after repeated printing, no defective cleaning occurs, and abnormal images are generated. Is suppressed, a high-quality image is stably obtained, and a mechanism in which the lubricant application means is removed, and even when a spherical toner is used, a highly stable low surface friction coefficient is maintained. It was confirmed that it was possible.
On the other hand, conditions that do not satisfy the requirements of the claims of the present invention, for example, the radical polymerizable monomers of Comparative Example 1 and Comparative Example 1 using a thiol containing no lubricating material and a dispersion aid and having one functional group are changed. Comparative Example 2 using a thiol having one functional group and not containing a lubricating material and a dispersion aid Comparative Example 3 using a thiol containing no lubricating material and a dispersing aid and having three functional groups, a lubricating material Comparative Example 4 using a thiol having 4 functional groups and no dispersion aid, Radical Polymerization Monomer, Lubricating Material, Comparative Example 5 using 2 Thiols having no Functionality, and Radical Polymerization Comparative Example 6 using no monofunctional radical polymerizable compound and a non-crosslinked structure, and a thiol having two functional groups as a donor, the lubricant material and the dispersion aid. Agent First, Comparative Example 7 using a monofunctional radical polymerizable compound and a non-crosslinked structure as a donor, a radical polymerizable monomer (trifunctional), and a thiol having two functional groups, a thiol, a lubricating material, and a dispersion aid Comparative Example 8 containing no thiol, Comparative Example 9 containing no thiol, Comparative Example 10 containing no lubricating material and a dispersion aid, Comparative Example 11 in which a thiol having one functional group is used, and Bifunctional having a charge transporting structure Comparative Example 12 using a radical polymerizable compound of No. 5, Comparative Example 13 having a lubricating material content of less than 5% by weight (4% by weight), Lubricating material content exceeding 50% by weight (55% by weight) ), Comparative Example 14 in which content of dispersion aid exceeds 20% by weight (22% by weight), Comparative Example 15 in which content of dispersion aid is less than 5% by weight (1% by weight), Content of dispersion aid The amount exceeds 20% by weight 25% by weight) Comparative Example 16, Comparative Example 17 not using a dispersion aid, Comparative Example 18 using a non-crosslinked structure (no radical polymerizable functional group) as a donor, and no radical polymerizable monomer ( (Comparative Example 19 uses any non-crosslinked resin) In all of Comparative Examples 19, after repeated printing, the evaluation was worsened in any of evaluations such as bright portion potential increase, poor cleaning, increased wear amount, etc. Admitted.

  Next, examples in which the surface layer of the electrophotographic photosensitive member is formed by heating will be described in Examples 16 to 43 below. In Comparative Examples 20 to 35, in addition to the example formed by heating, an example formed by light energy irradiation will be described.

[Example 16]
(Method for producing electrophotographic photoreceptor)
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and a 20 μm charge transport layer were formed. Further, a surface layer coating solution having the following composition was applied by a spray coating method, a coil heater was brought into contact with the inside of the aluminum cylinder, and the aluminum cylinder surface was heated for 2 minutes under heating conditions at 160 ° C. The heating was performed in an environment where the oxygen concentration was 5% by volume. As a result, an electrophotographic photosensitive member having a surface layer with a thickness of 7 μm was obtained.
In addition, the surface layer coating solution is a dispersion of a lubricating material, a dispersion aid, and tetrahydrofuran using a zirconia ball media having a diameter of 0.1 mm and a small shaker (VXR Basic IKA-Vibrax) for 1 hour at 1000 rpm. A dispersion liquid was prepared, and the surface layer coating liquid 35 was prepared by adding another constituent material thereto.

(Coating liquid for undercoat layer)
・ Alkyd resin: 6 parts by weight (Beckosol 1307-60-EL manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts by weight (Dainippon Ink & Chemicals Super Becamine G-821-60)
Titanium oxide (CR-EL manufactured by Ishihara Sangyo): 40 parts by weight Methyl ethyl ketone: 50 parts by weight

(Coating solution for charge generation layer)
-Bisazo pigment represented by the following structural formula (13): 2.5 parts by weight

Polyvinyl butyral (UCC XYHL): 0.5 parts by weight Cyclohexanone: 200 parts by weight Methyl ethyl ketone: 80 parts by weight

(Coating liquid for charge transport layer)
-Bisphenol Z polycarbonate: 10 parts by weight (Teijin Chemicals Panlite TS-2050)
-Charge transport material represented by the following structural formula (14): 7 parts by weight

Tetrahydrofuran: 100 parts by weight Silicone oil: 1 part by weight
[Diluted tetrahydrofuran solution of KF50-100CS manufactured by Shin-Etsu Chemical Co., Ltd. (
Solid content concentration is 1% by weight)]

(Coating liquid for surface layer)
-Radical polymerizable compound represented by the following structural formula (20): 50 parts by weight (monofunctional radical polymerizable compound having a charge transporting structure)

-Radical polymerizable monomer having no charge transporting structure: 45 parts by weight (SR295 manufactured by Sartomer, pentaerythritol tetraacrylate,
Tetrafunctional acrylate)
-Multifunctional thiol: 5 parts by weight (Showa Denko Karenz MT BD1, 1,4-bis (3-
Mercaptobutyryloxy) butane, bifunctional thiol)
・ Lubricant material (Daikin Kogyo's Lubron L2, PTFE fine particles): 7 parts by weight Dispersing aid: 50 parts by weight (NOF Corporation Modiper F206, fluorine-based block copolymer,
Solid content concentration 30% by weight)
Thermal polymerization initiator: 10 parts by weight (V-60 manufactured by Wako Pure Chemical Industries, azobisisobutyronitrile)
Tetrahydrofuran: 450 parts by weight

[Example 17]
An electrophotographic photoreceptor 36 of Example 17 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was changed to 10 parts by weight.

[Example 18]
An electrophotographic photoreceptor 37 of Example 18 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was 13 parts by weight.

[Example 19]
An electrophotographic photoreceptor 38 of Example 4 was produced in the same manner as in Example 1 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was changed to 30 parts by weight.

[Example 20]
An electrophotographic photoreceptor 39 of Example 20 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was changed to 50 parts by weight.

[Example 21]
An electrophotographic photoreceptor 40 of Example 21 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was changed to 75 parts by weight.

[Example 22]
An electrophotographic photoreceptor 41 of Example 22 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was 85 parts by weight.

[Example 23]
An electrophotographic photoreceptor 42 of Example 23 was produced in the same manner as in Example 16 except that the amount of the lubricating material contained in the surface layer coating solution of Example 16 was 115 parts by weight.

[Example 24]
An electrophotographic photosensitive member 43 of Example 24 was produced in the same manner as in Example 16 except that the surface layer coating solution of Example 16 was changed as follows.
(Coating liquid for surface layer)
Compound represented by the following structural formula (15): 50 parts by weight (monofunctional radically polymerizable compound having a charge transporting structure)

-Radical polymerizable monomer having no charge transport structure (trifunctional): 45 parts by weight (Tokyo Chemical Industry's trimethylolpropane triacrylate,
Trifunctional acrylate)
-Polyfunctional thiol: 5 parts by weight (Karenz MT NR1, 1,3,5-tris (3-
Mercaptobutyryloxyethyl) -1,3,5-triazine-
2,4,6 (1H, 3H, 5H) -trione, trifunctional thiol)
Lubricant material: 45 parts by weight (Mitsui / DuPont Fluorochemical TLP10F-1,
PTFE fine powder)
-Dispersing aid: 12.1 parts by weight (GF400 manufactured by Toa Gosei, fluorine block copolymer,
(Solid content concentration 24.8% by weight)
-Thermal polymerization initiator (Tokyo Chemical Industry, benzoyl peroxide): 10 parts by weight-Tetrahydrofuran: 450 parts by weight

[Example 25]
An electrophotographic photosensitive member 44 of Example 25 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was 20.2 parts by weight.

[Example 26]
An electrophotographic photoreceptor 45 of Example 26 was produced in the same manner as in Example 9 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was changed to 28.2 parts by weight.

[Example 27]
An electrophotographic photoreceptor 46 of Example 27 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was changed to 52.4 parts by weight.

[Example 28]
An electrophotographic photoreceptor 47 of Example 28 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was 80.6 parts by weight.

[Example 29]
An electrophotographic photoreceptor 48 of Example 29 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was changed to 108.9 parts by weight.

[Example 30]
An electrophotographic photosensitive member 49 of Example 30 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was changed to 129 parts by weight.

[Example 31]
An electrophotographic photosensitive member 50 of Example 31 was produced in the same manner as in Example 24 except that the amount of the dispersion aid contained in the surface layer coating solution of Example 24 was changed to 145.2 parts by weight.

[Example 32]
The monofunctional radically polymerizable compound having a charge transporting structure contained in the coating liquid for surface layer of Example 19 was changed to a monofunctional radically polymerizable compound represented by the following structural formula (21). In the same manner as in Example 19, an electrophotographic photoreceptor 51 of Example 32 was produced.

[Example 33]
The monofunctional radical polymerizable compound having a charge transporting structure contained in the coating liquid for surface layer of Example 19 was changed to a monofunctional radical polymerizable compound represented by the following structural formula (22). In the same manner as in Example 19, an electrophotographic photoreceptor 52 of Example 18 was produced.

[Example 34]
Example 19 except that the radical polymerizable monomer having no charge transporting structure contained in the coating liquid for surface layer of Example 19 was changed to trimethylolpropane trimethacrylate (trifunctional methacrylate) manufactured by Tokyo Chemical Industry Co., Ltd. In the same manner as described above, an electrophotographic photoreceptor 53 of Example 34 was produced.

[Example 35]
Example 19 except that the polyfunctional thiol contained in the surface layer coating liquid of Example 19 was changed to Showa Denko Karenz MT PE1 [pentaerythritol tetrakis (3-mercaptobutyrate), tetrafunctional thiol]. Similarly, an electrophotographic photosensitive member 54 of Example 35 was produced.

[Example 36]
The same as Example 19 except that the polyfunctional thiol contained in the surface layer coating solution of Example 19 was changed to TEMB (trimethylolethanetris (3-mercaptobutyrate), trifunctional thiol) manufactured by Showa Denko. Then, an electrophotographic photosensitive member 55 of Example 36 was produced.

[Example 37]
The same as Example 19 except that the polyfunctional thiol contained in the surface layer coating solution of Example 19 was changed to TPMB (trimethylolpropane tris (3-mercaptobutyrate), trifunctional thiol) manufactured by Showa Denko. Then, an electrophotographic photosensitive member 56 of Example 37 was produced.

[Example 38]
The lubricating material contained in the surface layer coating liquid of Example 19 was changed to XC99-A8808 (silicone resin fine particles) manufactured by Momentive Performance Materials Japan, and the dispersion aid was KP-578 manufactured by Shin-Etsu Chemical Co., Ltd. An electrophotographic photosensitive member 57 of Example 38 was produced in the same manner as in Example 19 except that (acrylic silicone) was used.

[Example 39]
Example 39 is the same as Example 38 except that the lubricating material contained in the surface layer coating solution of Example 38 is changed to Tospearl 120 (silicone resin fine particles) manufactured by Momentive Performance Materials Japan. An electrophotographic photosensitive member 58 was produced.

[Example 40]
The electrophotographic image of Example 40 as in Example 38, except that the lubricating material contained in the surface layer coating liquid of Example 38 was changed to X-52-854 (silicone resin powder) manufactured by Shin-Etsu Chemical Co., Ltd. A photoreceptor 59 was produced.

[Example 41]
The lubricating material contained in the surface layer coating liquid of Example 19 was changed to Kitamura KTL-2N (PTFE fine powder), and the dispersion aid was changed to NOF MODIPER F606 (fluorinated block copolymer). An electrophotographic photoreceptor 60 of Example 26 was made in the same manner as Example 19 except for the above.

[Example 42]
The lubricating material contained in the coating liquid for the surface layer of Example 19 was changed to KTL-4N (PTFE fine powder) manufactured by Kitamura, and the dispersion aid was S-386 (fluorine-based surfactant) manufactured by ACG Seimi Chemical. An electrophotographic photosensitive member 61 of Example 42 was produced in the same manner as in Example 19 except for changing to.

[Example 43]
The lubricating material contained in the surface layer coating liquid of Example 19 was changed to KTL-500F (PTFE fine powder) manufactured by Kitamura, and the dispersing aid was PF-656 (fluorine-based surfactant) manufactured by Kitamura Chemical Co., Ltd. An electrophotographic photosensitive member 62 of Example 43 was produced in the same manner as in Example 19 except for changing to.

[Comparative Example 20]
An electrophotographic photosensitive member 63 of Comparative Example 20 was produced in the same manner as in Example 35 except that the monofunctional radical polymerizable compound having a charge transporting structure contained in the surface layer coating solution of Example 35 was omitted. did.

[Comparative Example 21]
The monofunctional radically polymerizable compound having a charge transporting structure contained in the coating solution for the surface layer of Example 35 is a charge transporting property having no radical polymerizable functional group represented by the following structural formula (14). An electrophotographic photosensitive member 64 of Comparative Example 21 was produced in the same manner as in Example 35 except that the chemical composition was changed.

[Comparative Example 22]
The monofunctional radically polymerizable compound having a charge transporting structure contained in the surface layer coating liquid of Example 35 is converted into a bifunctional radically polymerizable compound having a charge transporting structure represented by the following structural formula (23). An electrophotographic photoreceptor 65 of Comparative Example 22 was produced in the same manner as Example 35 except that the compound was used.

[Comparative Example 23]
The electrophotographic photosensitive member of Comparative Example 23 is the same as Example 35 except that the tri- or higher functional radical polymerizable monomer having no charge transporting structure contained in the surface layer coating liquid of Example 35 is excluded. 66 was produced.

[Comparative Example 24]
The radical polymerizable monomer having no charge transporting structure contained in the coating solution for the surface layer of Example 35 was changed to a bifunctional radical polymerizable monomer (Shin-Nakamura Chemical Industrial ABE-300: Ethoxylated bisphenol A diester). An electrophotographic photoreceptor 67 of Comparative Example 24 was produced in the same manner as in Example 35 except that the acrylate and bifunctional acrylate were used. That is, monomers having 3 or more radical polymerizable functional groups were excluded.

[Comparative Example 25]
An electrophotographic photoreceptor 68 of Comparative Example 25 was produced in the same manner as in Example 35 except that the polyfunctional thiol contained in the surface layer coating solution of Example 35 was removed.

[Comparative Example 26]
Comparative Example as in Example 35 except that the polyfunctional thiol contained in the surface layer coating solution of Example 35 was changed to 3-methoxybutyl 3-mercaptopropionate (monofunctional thiol) manufactured by Tokyo Chemical Industry Co., Ltd. 26 electrophotographic photoreceptors 69 were produced.

[Comparative Example 27]
An electrophotographic photoreceptor 70 of Comparative Example 27 was produced in the same manner as in Example 35 except that the lubricating material contained in the surface layer coating solution of Example 35 was omitted.

[Comparative Example 28]
An electrophotographic photoreceptor 71 of Comparative Example 28 was produced in the same manner as in Example 35 except that the weight of the lubricating material contained in the surface layer coating solution of Example 35 was changed to 5 parts by weight.

[Comparative Example 29]
An electrophotographic photoreceptor 72 of Comparative Example 29 was produced in the same manner as in Example 35 except that the weight of the lubricating material contained in the surface layer coating solution of Example 35 was changed to 125 parts by weight.

[Comparative Example 30]
An electrophotographic photoreceptor 73 of Comparative Example 30 was produced in the same manner as in Example 35 except that the dispersion aid contained in the surface layer coating solution of Example 35 was omitted.

[Comparative Example 31]
An electrophotographic photoreceptor 74 of Comparative Example 31 was produced in the same manner as in Example 35 except that the weight of the dispersion aid contained in the surface layer coating solution of Example 35 was changed to 1.5 parts by weight.

[Comparative Example 32]
An electrophotographic photoreceptor 75 of Comparative Example 32 was produced in the same manner as in Example 35 except that the weight of the dispersion aid contained in the surface layer coating solution of Example 35 was changed to 37 parts by weight.

[Comparative Example 33]
An electrophotographic photoreceptor 76 of Comparative Example 33 was produced as described in Example 2 of Japanese Patent No. 4762789. This is a comparative example in which the polyfunctional thiol, the lubricating material, and the dispersion aid of the present invention are not included, and the surface layer is crosslinked by light energy irradiation means.

[Comparative Example 34]
An electrophotographic photoreceptor 77 of Comparative Example 34 was produced as described in Example 1 of JP2012-159521. This is a comparative example that does not contain the lubricating material and dispersion aid of the present invention.

[Comparative Example 35]
An electrophotographic photoreceptor 78 of Comparative Example 35 was produced as described in Example 1 of JP2013-73023A. This is a comparative example that does not contain the lubricating material and dispersion aid of the present invention.

  The materials used for preparing the surface layers of the electrophotographic photoreceptors obtained in Examples 16 to 43 and Comparative Examples 20 to 35 are shown in Table 6 (Examples) and Table 7 (Comparative Examples) below. Note that the contents of the lubricating material and the dispersion aid are separately summarized in Table 8. The contents of the lubricating material and the dispersion aid shown in Tables 6 to 8 are expressed as values converted to weight% of each component with respect to the total solid content of the surface layer.

Next, methods for evaluating the electrophotographic photoreceptors of Examples 16 to 43 and Comparative Examples 20 to 35 will be described.
Durability test 1
Except for external lubrication agent coating means, the physical properties at 25 ° C. are 70 degrees hardness (the sample is approximately 2 mm thick so that the thickness is 6 mm or more, and conforms to JIS K6253 using Shimadzu durometer) Rebound resilience is 50% (the sample is measured according to JIS K6255 using a Toyo Seiki Seisakusho No. 221 regi-reenester) with a sheet of about 2 mm stacked so that the thickness is 4 mm or more. Examples 1-27 produced in a process cartridge for an electrophotographic apparatus in which a urethane rubber blade manufactured by Toyo Tire & Rubber Co., Ltd. was fixed to a sheet metal holder with an adhesive, and mounted so that the linear pressure was 20 g / cm and the cleaning angle was 80 °. In addition, the electrophotographic photosensitive member of Comparative Examples 1 to 17 was mounted, and the initial dark section electric current was measured with an imaginary Color 5100 manufactured by Ricoh There was measured the initial light potential by the charging conditions as the -750 V.
Thereafter, 50,000 sheets of A4 paper on which characters having an image area ratio equivalent to 10% were written on average were printed, and a durability test was performed. The dark part potential and the bright part potential were measured under the charging conditions initially set after the printing of 50,000 sheets. The results are shown in Table 9.
Furthermore, the printed output image was visually confirmed, and the presence / absence of occurrence of abnormal images such as defective cleaning was evaluated. The results are shown in Table 10.
The toner used in the durability test was prepared by a polymerization method, and the toner physical properties were a toner base with a circularity of 0.98 and an average particle size of 4.9 μm. Further, the film thickness of the electrophotographic photosensitive member before and after the printing test was measured using an eddy current film thickness measuring device manufactured by Fischer Instruments, and the amount of wear of the electrophotographic photosensitive member in the printing test was measured. The results are shown in Table 10.

Further, the following durability tests were performed on the electrophotographic photosensitive members of Examples 16 to 43.
Durability test 2
The cleaning blade used in the above durability test 1 is hardened in the vicinity of the tip ridge line using a urethane acrylate oligomer which is a high hardness material as follows, and the linear pressure is set to 30 g / cm. A 10,000-sheet printing test was conducted.
Manufacturing method of cleaning blade with high hardness in the vicinity of the tip edge line Spray the surface layer coating solution of the following formula on the urethane rubber blade used in the durability test 1 from two directions of the blade surface and the tip surface. Cleaning using a UV lamp system (metal halide lamp) manufactured by Denki Co., Ltd., by light curing the surface layer by irradiating light under the conditions of illuminance: 600 mW / cm 2 and irradiation time: 30 seconds, and increasing the hardness of the vicinity of the edge of the tip A blade was produced.
Formulation of surface layer coating liquid Urethane acrylate oligomer 1 (UN-904 manufactured by Negami Kogyo): 10 parts by weight Urethane acrylate oligomer 2 (UN-2700 manufactured by Negami Kogyo): 10 parts by weight Photopolymerization initiator (IRGACURE 184 manufactured by BASF): 1 Part by weight 2-butanone: 80 parts by weight Table 11 shows the presence or absence of abnormal images and the amount of wear on the electrophotographic photosensitive member.

From the results of Tables 9, 10, and 11, the photoreceptors of Examples 16 to 43 that satisfy the claims of the present invention have little bright portion potential increase after repeated printing, no cleaning failure occurs, and abnormal images Occurrence is suppressed, high-quality images can be stably obtained, and a mechanism that removes the lubricant application means and maintains a highly stable and low surface friction coefficient even when spherical toner is used. It was confirmed that it was possible to do.
On the other hand, conditions that do not satisfy the requirements of the claims of the present invention, for example, Comparative Example 20 including no donor (a monofunctional radically polymerizable compound having a charge transporting structure), a donor having a non-crosslinked structure [Structural Formula (14 )], Comparative Example 22 in which the donor is a bifunctional radically polymerizable compound, Comparative Example 23 that does not include a radically polymerizable monomer having no charge transporting structure, and three or more radically polymerizable functional groups Comparative Example 24 excluding a monomer having a group, Comparative Example 25 not including a polyfunctional thiol having two or more functional groups, Comparative Example 26 using a thiol having one functional group, and Comparative Example 27 not including a lubricating material Comparative Example 28 in which the content of the lubricating material is less than 5% by weight (4.17% by weight), Comparative Example 29 in which the content of the lubricating material exceeds 50% by weight (52.08% by weight), dispersion aid Do not contain agents Comparative Example 30, Comparative Example 31 in which the content of the dispersion aid is less than 5% by weight (1.14% by weight), and Comparative Example 32 in which the content of the dispersion aid exceeds 20% by weight (22.16% by weight) Comparative Example 33, Comparative Example 34, and Comparative Example 35, which do not contain a lubricating material and a dispersion aid, all deteriorated in any of the evaluations such as bright portion potential increase, poor cleaning, and increased wear after repeated printing. However, abnormal images were generated and image quality was degraded.

  That is, the electrophotographic photosensitive member of the present invention has an extremely small coefficient of friction and wear even after long-term use, and is excellent in cleaning properties. Occurrence of abnormal images such as unevenness and background stains is suppressed, and stable and high-quality image formation is possible. Such an electrophotographic photosensitive member is useful in copying machines, laser printers, facsimiles, and the like, and has been strongly demanded in image forming apparatuses and image forming methods. Can deal with gender.

(Reference numerals in FIGS. 1 to 4)
31 conductive support)
32 subbing layer 34 photosensitive layer 35 surface layer 37 charge generation layer 38 charge transport layer (reference numeral in FIG. 5)
DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer body (transfer paper)
10 Transfer Charger 11 Separation Charger 12 Separation Claw 13 Charger 14 Before Cleaning Fur Brush 15 Cleaning Blade (reference numeral in FIG. 6)
DESCRIPTION OF SYMBOLS 101 Photoconductor 102 Charging means 103 Exposure means 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means

JP 2000-162881 A Japanese Patent Laid-Open No. 11-218953 JP-A-11-272003 JP 2001-125286 A JP 2001-324857 A JP 2003-98708 A JP-A-5-181299 JP 2002-6526 A JP 2002-82465 A JP 2000-284514 A JP 2000-284515 A JP 2001-194413 A Japanese Patent No. 3194392 Japanese Patent No. 3286704 Japanese Patent No. 4762789 (Japanese Patent Laid-Open No. 2007-322483) JP 2012-159521 A JP 2013-73023 A

Claims (10)

In an electrophotographic photosensitive member having at least a photosensitive layer and a surface layer on a conductive support,
The surface layer contains a cured resin having a crosslinked structure, a lubricating material, and a dispersion aid,
The cured resin is a cured product of a polyfunctional thiol having two or more functional groups, a monofunctional radical polymerizable compound having a charge transporting structure, and a radical polymerizable monomer having no charge transporting structure. The radical polymerizable monomer having no charge transporting structure contains a monomer having at least three radical polymerizable functional groups, and the content of the lubricating material is based on the total solid content of the surface layer. An electrophotographic photoreceptor, wherein the content of the dispersion aid is in the range of 2 to 20% by weight relative to the total solid content of the surface layer.   2. The electrophotographic photoreceptor according to claim 1, wherein the charge transport structure of the monofunctional radically polymerizable compound having the charge transport structure is a triarylamine structure. 3. The electrophotographic photosensitive member according to claim 1, wherein the monofunctional radically polymerizable compound having a charge transporting structure is represented by any one of the following general formulas (4) and (5). body.
[In the formulas (4) and (5), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₆ (R ₆ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group), a carbonyl halide group or CONR ₇ R ₈ (R ₇ and R ₈ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or Represents an aryl group which may have a substituent and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and may be the same or different May be. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ] The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the monofunctional radically polymerizable compound having a charge transporting structure is represented by the following general formula (9).
[In the formula (9), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. Multiple and may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (10), (11), and (12). ]
The electrophotographic photosensitive member according to claim 1, wherein the lubricating material is fluororesin fine particles. 6. The electrophotographic photosensitive member according to claim 1, wherein the dispersion aid is a fluorine-based dispersion aid.   7. The electrophotographic photosensitive member according to claim 1, wherein the curable resin is a cured product having a crosslinked structure by at least one of heating and light energy irradiation.   An image forming method, wherein at least charging, image exposure, development, and transfer are repeated using the electrophotographic photosensitive member according to claim 1.   An image forming apparatus comprising: the electrophotographic photosensitive member according to claim 1; and a charging unit, an exposure unit, a developing unit, and a transfer unit. 8. An electrophotographic photosensitive member according to claim 1, comprising at least one of an electrostatic latent image forming unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit. Process cartridge.