JP2007004141A - Electrophotographic photoreceptor and image forming method using the electrophotographic photoreceptor - Google Patents

Abstract

【選択図】なしThe present invention provides an image with high resolving power, little occurrence of image defects even in repeated use, and inconspicuous image defects even under severe conditions such as high resolution and excellent electrical characteristics. To provide an image forming method using a photographic process.
An electrophotographic photosensitive member for developing an electrostatic latent image formed on a surface with a polymerized toner, the photosensitive layer comprising a repeating unit including a partial structure represented by the formula (1). The problem has been solved by an electrophotographic photosensitive member characterized by containing a polymer.

[Selection figure] None

Description

  The present invention relates to an electrophotographic photosensitive member used for a copying machine or a printer using an electrophotographic process, and more specifically, it has excellent durability even when developed using a polymerized toner, and fog, memory, etc. The present invention relates to an electrophotographic photosensitive member that does not cause image defects.

  In recent years, electrophotographic technology is widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high quality images. In recent years, the electrophotographic photosensitive member in the electrophotographic technology has used an organic photoconductive material having advantages such as non-polluting, easy film formation, and easy manufacture as the photoconductive material. Photoconductors have been developed.

  Electrophotographic photoreceptors using organic photoconductive materials include so-called dispersed photoreceptors in which photoconductive fine powder is dispersed in a binder resin, and laminated photoreceptors in which a charge generation layer and a charge transport layer are laminated. Are known. In addition, in the laminated type photoreceptor, a forward laminated type photoreceptor in which the charge generation layer and the charge transport layer are laminated on the conductive substrate in this order, and an inverse laminated type photoreceptor in which the charge transport layer and the charge generation layer are laminated in this order. It has been known.

  In particular, the laminated type photoconductor can be obtained by combining a highly efficient charge generating material and charge transporting material, so that a highly sensitive electrophotographic photoconductor can be obtained, and an electrophotographic photoconductor having a wide material selection range and high safety can be obtained. In addition, since the productivity of coating is high and relatively advantageous in terms of cost, it has been developed and put into practical use as the mainstream of electrophotographic photoreceptors.

  On the other hand, polymer toners have been developed in place of conventional pulverized toners because toners used in the electrophotographic process can be obtained with a relatively small particle size and have a sharp particle size distribution.

  Incidentally, since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle such as charging, exposure, development, transfer, cleaning, and static elimination, it is deteriorated by various stresses.

  Such deterioration includes, for example, strongly oxidative ozone and NOx generated from a corona charger normally used as a charger, which chemically damages the photosensitive layer, or a carrier (current) generated by image exposure. ) Flows in the photosensitive layer, or the photosensitive layer composition is decomposed by static electricity or external light.

  There is also mechanical degradation due to the electrophotographic photosensitive member coming into contact with toner, paper, and a cleaning member in the development, transfer, and cleaning steps. In particular, when a polymer toner having a relatively small particle diameter and a nearly spherical shape is used, it may be necessary to strongly contact a cleaning member such as a cleaning blade with the electrophotographic photosensitive member. In particular, mechanical deterioration has been a problem.

  Such deterioration causes image defects such as fogging, memory, white stripes, black stripes, white spots, black spots, white spots, black spots on the image, and shortens the life of the electrophotographic photosensitive member. It was the cause.

  In particular, when a polymerized toner is used, the average particle diameter is generally small, so that the image is sharp and resolution is good, and the above-mentioned image defect is easily noticeable. Was desired.

  It is usually the outermost layer that is susceptible to electrical, chemical or mechanical loads. Except for the case where a protective layer or the like is provided, the photosensitive layer itself is the outermost layer in the case of the dispersion type photosensitive member, and the charge transporting layer is the outermost layer in the case of the sequentially laminated type photosensitive member. And as far as mechanical degradation is concerned, the strength of the outermost layer is the most important factor.

  On the other hand, various thermoplastic resins and thermosetting resins are used as the outermost binder resin. Among these various binder resins, various polycarbonate resins have been developed and put into practical use (for example, see Patent Document 1).

  However, the photosensitive layer of the dispersion type photosensitive member that is the outermost layer and the charge transporting layer of the sequentially laminated type photosensitive member usually contain a binder resin and a photoconductive substance, and the content of this photoconductive substance is considerably large. For this reason, conventionally, sufficient mechanical strength has not been achieved. In particular, when developing using polymerized toner, the outermost layer has not been given sufficient mechanical strength to withstand the load received from the cleaning member or the like.

  Therefore, even if development is performed using a polymerized toner whose contact pressure on the cleaning blade is inevitably increased, the degradation of the electrophotographic photosensitive member can be sufficiently reduced, and the polymerized toner has good resolution and conspicuous image defects. There has been a demand for a more durable organic electrophotographic photosensitive member in which the above-described image defects do not occur even when using.

Japanese Unexamined Patent Publication No. 63-148263

  The present invention has been made in view of the background art, and the problem is that an image with high resolution can be obtained, image defects are less likely to occur even during repeated use, and severe conditions of high resolution are required. However, an object of the present invention is to provide an electrophotographic photosensitive member in which such image defects are not conspicuous and have excellent electrical characteristics.

  As a result of diligent studies to solve the above problems, the present inventor has included a specific polymer as a binder resin in the outermost layer of the electrophotographic photosensitive member, so that electric properties such as chargeability, sensitivity, and residual potential can be obtained. It has been found that an electrophotographic photosensitive member that solves the above problems can be obtained without impairing properties, coating performance, and the like. In addition, by combining such an electrophotographic photoreceptor and a polymerized toner, an image with high resolution can be obtained, and image defects are less likely to occur even in severe repeated use due to the use of polymerized toner. Under the present circumstances, the present inventors have found that such image defects are not conspicuous and have excellent durability performance, and have reached the present invention.

  That is, the present invention is an electrophotographic photosensitive member for developing an electrostatic latent image formed on a surface with a polymerized toner, and the photosensitive layer includes a repeating unit including a partial structure represented by the formula (1). The present invention provides an electrophotographic photosensitive member characterized by containing a polymer.

  The present invention also provides an image forming apparatus having the electrophotographic photosensitive member.

  According to the present invention, it is possible to obtain an image with high resolution, not to mention the occurrence of image defects such as image fogging or memory even when it is used repeatedly, as well as at the start of use, and it can be used repeatedly. However, it is possible to provide an electrophotographic photosensitive member that has little change in an image having high resolution, excellent durability, good coating performance of a coating solution for forming a photosensitive layer, and excellent electrical characteristics. In addition, even when charged with a contact charging member, an electrophotographic photosensitive member having less physical deterioration of the photosensitive layer such as film loss in repeated use and having excellent electrical characteristics can be provided.

  In the present invention, it is essential that the photosensitive layer of the electrophotographic photoreceptor contains a polymer composed of repeating units including the partial structure represented by the above formula (1).

  The photosensitive layer of the electrophotographic photosensitive member in the present invention is not particularly limited, but the effect of the present invention is easily achieved when it is the outermost layer of the electrophotographic photosensitive member. That is, except for the case where a protective layer or the like is provided, it is preferable that the photosensitive layer itself is a photosensitive layer in the dispersion type photoreceptor, and the charge transport layer is a photosensitive layer in the present invention.

  A polymer composed of a repeating unit containing a partial structure represented by the above formula (1) (hereinafter abbreviated as “polymer of the present invention”) is a minimal repeating of the partial structure represented by the formula (1). A polymer which is contained in units and is substantially composed of repeating units.

  The repeating unit including the partial structure represented by the formula (1) is not particularly limited, regardless of what organic group is bonded to both ends or one end of the partial structure, as long as such a partial structure is included. Although it can become the polymer of this invention and the effect of this invention is acquired, it is especially preferable that it is a repeating unit when this partial structure is polycondensed as a bisphenol component.

  The basic skeleton of the main chain of the polymer of the present invention is not particularly limited, but is preferably polycarbonate and / or polyester.

  Specific examples of the repeating unit including the partial structure represented by the formula (1) include a repeating unit represented by the formula (2) and a repeating unit represented by the formula (3).

  In formula (3), X represents an arbitrary divalent organic group. Examples of X include alkylenes such as methylene group and ethylene group; arylenes such as phenylene group and naphthylene group; aromatic ring sulfides such as diphenyl sulfide; and aromatic ring ethers such as diphenyl ether. Preferred examples of X include arylenes and aromatic ring ethers, and particularly preferred are phenylene groups and diphenyl ethers. More preferred is a phenylene group which is a terephthalic acid residue.

  The polymer of the present invention is a polymer composed of a repeating unit having the repeating unit including the partial structure represented by the formula (1) as the minimum repeating unit. That is, copolycondensation of other repeating units is not excluded as long as it does not impair the effects of the present invention. In the present invention, a polymer consisting essentially of such repeating units is used.

  An electrophotographic photoreceptor having sufficient durability even in combination with a polymerized toner, provided that the polymer contained in the photosensitive layer is substantially composed of a repeating unit containing a partial structure represented by the formula (1). Is obtained. Preferably, it is a polymer composed only of repeating units including the partial structure represented by the formula (1).

  If many repeating units other than the repeating unit including the partial structure represented by the formula (1) are copolycondensed in the polymer, the mechanical strength of the photosensitive layer may not be obtained. The fog value and memory value may increase. Further, when the cleaning member is strongly applied to the photosensitive layer, for example, by increasing the linear pressure of the cleaning blade for the polymerized toner, durability may not be sufficiently obtained. On the other hand, when the polymer is substantially composed of the repeating unit represented by the formula (1), excellent mechanical strength can be obtained.

  The photosensitive layer of the electrophotographic photoreceptor of the present invention contains a polycarbonate consisting essentially of a repeating unit represented by the formula (2) and / or a polyester consisting essentially of a repeating unit represented by the formula (3). It is preferable.

  Among these, it is particularly preferable to use a polymer composed of a repeating unit represented by the formula (2) in that durability due to repeated use is excellent.

  When the viscosity average molecular weight of the polymer of the present invention is too low, the mechanical strength is insufficient. Therefore, it is usually 10,000 or more, preferably 20,000 or more, particularly preferably 30,000 or more. In addition, if the viscosity average molecular weight is too high, the viscosity of the coating solution for forming the photosensitive layer becomes too high and the productivity may be lowered. Therefore, it is usually 150,000 or less, preferably 100,000 or less, particularly preferably 50,000. It is as follows.

In the present invention, the viscosity average molecular weight is defined as a value measured and calculated by the following method. That is, the polymer is dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Using a Ubbelohde capillary viscometer with a flow time t ₀ (second) of the solvent (dichloromethane) of 136.16 seconds, the flow time t (second) of the sample solution was measured in a constant temperature water bath set at 20.0 ° C. To do. The viscosity average molecular weight Mv is calculated according to the following formula.
a = 0.438 × η _sp +1 where η _sp = (t / t ₀ ) −1.
b = 100 × η _sp / C where C = 6.00 (g / L).
η = b / a
Mv = 3207 × η ^1.205

  For example, the method for synthesizing the polycarbonate composed of the repeating unit represented by the formula (2) is not particularly limited and can be synthesized according to a conventional method. For example, the polycarbonate can be synthesized by the production method described in JP-A-63-148263.

  Further, for example, a method for synthesizing a polyester comprising a repeating unit represented by the formula (3) is not particularly limited and can be synthesized according to a conventional method. For example, the polyester can be synthesized by a production method described in JP-A-9-22126. .

  The photosensitive layer of the electrophotographic photosensitive member of the present invention may contain a binder resin other than the polymer of the present invention. Such resins used in combination include polymers of vinyl compounds such as methyl methacrylate, styrene and vinyl chloride or copolymers thereof; polycarbonates other than the polymer of the present invention; polyesters other than the polymer of the present invention; Examples thereof include thermoplastic resins such as polysulfone, phenoxy resin, epoxy resin, and silicon resin, and thermosetting resins. Among these resins, polycarbonate resins other than the polymer of the present invention, polyester resins other than the polymer of the present invention, and the like are preferable.

  Specific examples of the polycarbonate resin and polyester resin other than the polymer of the present invention include those containing repeating units represented by the formulas (4) to (7).

  When the binder resin other than the polymer of the present invention is contained, the polymer of the present invention is 50% by mass or more based on the total binder resin of the photosensitive layer in order to maintain the mechanical properties of the electrophotographic photosensitive member of the present invention. It is preferably contained, and particularly preferably 80% by mass or more. More preferably, it is a case where the binder resin of the photosensitive layer is substantially composed only of a polymer (polymer of the present invention) composed of a repeating unit containing a partial structure represented by the formula (1).

  The electrophotographic photosensitive member of the present invention is preferably charged by a contact charging member that contacts the electrophotographic photosensitive member in order to take advantage of its excellent durability, and the contact charging member is a roller-shaped contact charging member. It is particularly preferred.

  For example, when the contact charging device is a roller-shaped contact charging member, the charging roller 2 is usually composed of at least a core member and a contact charging member that covers the periphery thereof. As the contact charging member, a conductive or semiconductive elastic body having a relatively low surface hardness and a low elastic modulus is preferable because it needs to be brought into close contact with the photosensitive member. For example, conductive particles such as carbon are used as a rubber material. Alternatively, conductive rubber containing other semiconductive particles is preferably used. In addition, the contact charging member is divided into a support member and a surface member, and the support member has an appropriate hardness so that the surface member maintains an appropriate electrical resistance while maintaining adhesion to the photosensitive member. A member can also be used especially suitably. An embodiment using a roller-shaped charging member will be described in more detail with reference to FIG.

  In FIG. 2, 1 is an electrophotographic photosensitive member, and the shape may be any of a drum shape, a sheet shape, a belt shape, and the like. A core material 21 supports the contact charging member. Both ends of the core material 21 are held by a bearing supported by an appropriate pressure application device, such as a metal spring, in order to bring the contact charging member into contact with the electrophotographic photosensitive member 1. Then, a bias potential is applied to the bearing of the core member 21 directly or using other electrical contact means. The material of the core material 21 is not particularly limited as long as it has conductivity, but usually a metal is used. Examples of such metals include iron, copper, brass, stainless steel, aluminum and the like. In addition, it is also possible to use a conductive organic material such as a resin molded product in which carbon is kneaded.

  In FIG. 2, reference numeral 22 denotes a roller-like support member that is in close contact with the electrophotographic photosensitive member and rotates. The rotational driving force may be applied from the outside, or may be freely rotated by the contact frictional force with the electrophotographic photosensitive member 1. The material of the support member 22 is not particularly limited as long as it has conductivity or semiconductivity. For example, a rubber material having a relatively low surface hardness, for example, since it needs to be brought into close contact with the electrophotographic photosensitive member 1, for example, NBR, EPDM, silicone, neoprene or natural rubber materials, or conductive rubber materials in which conductive particles such as carbon or semiconductive particles are kneaded into these rubber materials are used. Of course, as the material of the support member 22, a material other than a material having a low elastic modulus such as rubber may be used as long as it has a surface precisely processed so as to maintain good adhesion. good.

When the above-described roller-shaped contact charging device 2a is used, the uniformity of charging becomes a problem. If the volume resistivity of the contact charging member is too large, charging unevenness occurs in the electrophotographic photosensitive member, and the black portion is not developed during normal development. During image unevenness and reversal development, fogging of white portions is likely to occur. On the other hand, if the volume resistivity is too small, charging failure may occur and the electrophotographic photosensitive member 1 may not be sufficiently charged. Therefore, the volume resistivity of the support member 22 is preferably 10 ² to 10 ¹⁵ Ωcm, and particularly preferably 10 ⁴ to 10 ¹² Ωcm, as measured by a method based on IEC 60093.

In FIG. 2, reference numeral 23 denotes a surface member, which is provided when a function separation type charging member is used. The material of the surface member 23 is not particularly limited. For example, polyamide resin, fluororesin, vinyl chloride resin, acrylic resin, and other various polyester resins are used as the main component. The volume resistivity of the surface member 23 is preferably 10 ³ to 10 ¹⁴ Ωcm, particularly preferably 10 ⁵ to 10 ¹² Ωcm, as measured by a method based on IEC 60093. The film thickness of the surface member 23 is preferably thick in consideration of durability due to wear as a charging member, but if it is too thick, the charging ability to the electrophotographic photosensitive member 1 is deteriorated, and therefore usually 0.01 μm to 1000 μm, Preferably it is used in the range of 0.1 μm to 500 μm. The surface member 23 is preferably formed on the support member 22 by a dip method, a spray method, a vacuum deposition method, a plasma coating method, or the like.

  In order to charge the electrophotographic photosensitive member 1, the voltage applied to the charging member, that is, the core material 21 may be only a direct current voltage, or an alternating current may be superimposed on the direct current. If it is a voltage which changes periodically as alternating current, a voltage waveform will not be specifically limited. The voltage range is preferably 100 V to 4000 V, particularly preferably 300 V to 3000 V, in the case of a DC voltage. As the alternating voltage to be superimposed, the peak-to-peak voltage is preferably 100V to 4000V, and particularly preferably 300V to 3000V. What is charged by a direct current voltage is preferable in that mechanical vibration is small.

Hereinafter, the aspect and manufacturing method of the electrophotographic photosensitive member of the present invention will be described for each component.
<Conductive support>
The electrophotographic photoreceptor of the present invention is usually constituted by forming a photosensitive layer on a conductive support. As such a conductive support, any of those used in known electrophotographic photoreceptors can be used. Specifically, for example, aluminum, aluminum alloy, stainless steel, copper, nickel, zinc, indium, gold, silver and other metal materials such as drums, sheets or laminates of these metal foils, deposits, or aluminum on the surface Insulating supports such as polyester film provided with a conductive layer such as copper, palladium, tin oxide, indium oxide, ITO (indium-tin oxide), and conductive polymer, paper, and glass. Furthermore, a plastic film, a plastic drum, paper, a paper tube, and the like obtained by applying a conductive material such as metal powder, carbon black, copper iodide, and a polymer electrolyte together with an appropriate binder to conduct a conductive treatment may be used. Further, a plastic sheet or drum containing a conductive material such as metal powder, carbon black, or carbon fiber and becoming conductive can be used. Moreover, the plastic film and belt which carried out the electroconductive process with electroconductive metal oxides, such as a tin oxide and an indium oxide, are mentioned.

  The surface of the conductive support can be subjected to various treatments, for example, surface oxidation treatment or chemical treatment within a range that does not affect the image quality. When a metal material such as an aluminum alloy is used as the conductive support, it may be used after being subjected to anodizing treatment, chemical conversion coating treatment, or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.

  The surface of the conductive support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support.

  The shape of the conductive support can take any shape such as a drum, a sheet, a belt, and a seamless belt.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesiveness, blocking property and the like. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. As the metal oxide particles, only one kind of particles may be used, or a plurality of kinds of particles may be mixed and used.

  Among these metal oxide particles, titanium oxide, aluminum oxide and the like are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or with an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, amorphous and the like can be used. A thing of a several crystalline state may be contained. Moreover, when using these metal oxide particles, a surface treatment may be applied to improve dispersibility in a coating solution and environmental characteristics. The surface treatment agent for the metal oxide particles is not particularly limited as long as the treated particles do not adversely affect the characteristics of the electrophotographic photoreceptor, but it is preferable to use a reactive organosilicon compound.

  Various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm to 100 nm, particularly preferably 10 nm to 50 nm. is there.

  Further, there is no particular limitation as long as it is an organic pigment having an electron transporting ability, which may be used in combination with the above-described inorganic metal oxide, or may contain an electron transporting organic pigment alone. Examples thereof include pigments, perylene pigments, azo pigments, indigo pigments, and quinacridone pigments.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is phenoxy resin, epoxy resin, polyvinyl pyrrolidone, polyvinyl alcohol, casein, poly (meth) acrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. alone or cured Of these, alcohol-soluble copolymerized polyamides and modified polyamides are preferred because they exhibit good dispersibility and coating properties. The mixing ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10% by mass to 500% by mass in terms of the stability of the dispersion and the coating property.

  The thickness of the undercoat layer can be arbitrarily selected, but is preferably in the range of 0.1 to 20 μm from the viewpoint of photoreceptor characteristics and applicability. The undercoat layer may contain a known antioxidant or the like.

<Configuration of photosensitive layer>
The photosensitive layer of the electrophotographic photosensitive member of the present invention can be used in any form of a so-called laminated type photosensitive layer or a dispersion type photosensitive layer, but the mechanical properties, electrical characteristics, and production of the electrophotographic photosensitive member can be used. In consideration of stability and the like, a normal lamination type photosensitive layer is preferable.

<< Laminated Photosensitive Layer >>
* Charge generation layer When the electrophotographic photoreceptor of the present invention is a multilayer photoreceptor, the charge generation material used in the charge generation layer is, for example, selenium or an alloy thereof; an inorganic photoconductive material such as cadmium sulfide; Organic pigments such as phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments and benzimidazole pigments are preferred, and organic pigments such as phthalocyanine pigments and azo pigments are particularly preferred.

  When a phthalocyanine compound is used as the charge generation material, specifically, a metal-free phthalocyanine; a metal such as copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof is arranged. Phthalocyanines are used. Examples of the ligand to a metal atom having 3 or more valences include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Of these, particularly sensitive X-type, T-type metal-free phthalocyanine, A-type, B-type, D-type titanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like are suitable. Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It has been shown by Heller et al. As phase I and phase II, respectively (Zeit. Kristallogr. 159 (1982) 173), and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα characteristic X-rays.

  As the phthalocyanine compound, only a single compound may be used, or several mixed states may be used. As a method for forming the phthalocyanine compound or the mixed state in the crystalline state here, the respective constituent elements may be mixed and used later, or the phthalocyanine compound production / treatment process such as synthesis, pigmentation, crystallization, etc. A mixed state may be generated in. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are used.

  The charge generation material is used alone or in combination with a binder resin to form the charge generation layer. Examples of the binder resin include polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, and cellulose ether; Polymers or copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid esters, methacrylic acid esters, vinyl alcohol and ethyl vinyl ether; polyamides, silicon resins and the like.

  The use ratio of the charge generating material is usually 5 to 500 parts by weight, preferably 20 to 300 parts by weight, with respect to 100 parts by weight of the binder resin. The film thickness of the charge generation layer is usually 0.01 μm to 5 μm, preferably 0.05 μm to 2 μm, more preferably 0.15 μm to 0.8 μm.

  In addition, the charge generation layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving coating properties as necessary.

  When forming the charge generation layer, the charge generation material is dispersed or dissolved in an appropriate dispersion medium using a ball mill, ultrasonic disperser, paint shaker, attritor, sand grinder, etc., and a binder resin is added as necessary to charge the charge generation layer. The coating solution for forming the generation layer is prepared, and this coating solution is formed by coating. When the charge generating material is used alone, the coating solution may be prepared and applied without adding a binder to the dispersion, or may be formed by a method such as vapor deposition or sputtering.

* Charge Transport Layer When the electrophotographic photoreceptor of the present invention has a function-separated type photosensitive layer, the charge transport layer is a multilayer consisting of at least a charge transport material and a repeating unit containing a partial structure represented by formula (1). It is formed containing a coalescence (polymer of the present invention).

  Examples of charge transport materials used in the charge transport layer include diphenoquinone derivatives, aromatic nitro compounds such as 2,4,7-trinitrofluorenone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxadiazole derivatives A heterocyclic compound such as a pyrazoline derivative and a thiadiazole derivative, an aniline derivative, a hydrazone compound, an aromatic amine derivative, a stilbene derivative, a butadiene derivative, an enamine compound, a combination of these compounds, or a group comprising these compounds Examples thereof include a polymer having a main chain or a side chain. In addition, you may use the said charge transport material in mixture of 2 or more types.

  In the present invention, the content ratio of the charge transport material and the binder resin is preferably 10 parts by weight or more, particularly preferably 30 parts by weight or more, based on 100 parts by weight of the binder resin. Moreover, 200 weight part or less is preferable and 150 weight part or less is especially preferable. If the content ratio of the binder resin is too large, the electrical characteristics may be deteriorated. In addition, the charge transport material is usually compatible with the binder resin and has a high influence on the mechanical properties of the photosensitive layer. Therefore, if the content ratio of the charge transport material is too large, the mechanical strength of the photosensitive layer decreases. As a result, the effects of the present invention may not be obtained.

  Furthermore, in the present invention, in order to improve the film transportability, flexibility, mechanical strength of the layer, coatability, stain resistance, gas resistance, light resistance, etc., in the charge transport layer, a known plasticizer, Additives such as a lubricant, a dispersion aid, an antioxidant, an ultraviolet absorber, an electron-withdrawing compound, a dye, a pigment, a sensitizer, and a leveling agent may be contained. In addition, various additives can be used to further improve the mechanical strength and durability of the coating film. Examples of such additives include known plasticizers, stabilizers, fluidity-imparting agents, and crosslinking agents. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Examples of surfactants include silicon oil and fluorine oil.

  About the film thickness of a charge transport layer, it is 10 micrometers-50 micrometers normally, Preferably, it is used by 13 micrometers-35 micrometers.

<< Dispersive photosensitive layer >>
When the electrophotographic photosensitive member of the present invention has a dispersion type photosensitive layer, the charge generating material is a polymer comprising a repeating unit containing the partial structure represented by the formula (1) together with the charge transporting material (the heavy weight of the present invention). Used in the layer containing the coalesced).

  At this time, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. The amount of the charge generating material dispersed or dissolved in the dispersion type photosensitive layer is, for example, in the range of 0.5 to 50% by mass with respect to the entire photosensitive layer. If the amount is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. Particularly preferably, it is used in the range of 1 to 20% by mass. The content ratio of the charge transport material and the binder resin is preferably 30 parts by weight or more, and particularly preferably 40 parts by weight or more with respect to 100 parts by weight of the binder resin. Moreover, 80 weight part or less is preferable and 60 weight part or less is especially preferable.

  As in the case of the charge transport layer in the multilayer photosensitive layer, if the content ratio of the binder resin is too large, the electrical characteristics may be deteriorated. In addition, since the charge transport material is usually compatible with the binder resin, if the content ratio of the charge transport material is too large, the mechanical strength of the photosensitive layer is lowered, and the effect of the present invention cannot be obtained. There is. Furthermore, the same additive as that which can be blended in the charge transport layer in the laminated photosensitive layer can be used in the dispersion type photosensitive layer.

  The resulting coating solution is coated on a conductive support and dried to form a photosensitive layer, and is usually 2 to 70 μm, preferably 10 to 45 μm, particularly preferably 20 to 35 μm.

<Coating solution for forming photosensitive layer>
Solvents and dispersion media used when applying the above layers include butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, Xylene, chloroform, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methyl alcohol , Ethyl alcohol, isopropyl alcohol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, and the like. These solvents may be used alone or in combination of two or more.

<Photosensitive layer forming method>
As a method for coating and forming a photosensitive layer, a spray coating method, a bar coater method, a blade method, a roll coater method, a wire bar coating method, a knife coater coating method, which are usually used for coating and forming a photosensitive layer of an electrophotographic photosensitive member. Any coating method such as a spiral coating method, a ring coating method, or a dip coating method can be used. A photosensitive layer is obtained by applying and then drying the coating solution.

  Spray coating methods include air spray, airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, and hot airless spray. Considering the degree of conversion, adhesion efficiency, etc., in the rotary atomizing electrostatic spray, the conveying method disclosed in the republished Japanese Patent Publication No. 1-805198, that is, the cylindrical workpiece is rotated while the axial direction is spaced. By using a continuous conveyance method, it is possible to obtain an electrophotographic photoreceptor excellent in film thickness uniformity with high overall deposition efficiency.

  Examples of the spiral coating method include a method using a liquid injection coating machine or a curtain coating machine disclosed in Japanese Patent Laid-Open No. 52-119651, and paint from a minute opening disclosed in Japanese Patent Laid-Open No. 1-2231966. A method of flying continuously in a streak shape, a method using a multi-nozzle body disclosed in JP-A-3-193161, and the like are used.

  As an example of the dip coating method, the following charge transport layer coating formation procedure may be mentioned. Using a charge transport material, a binder resin, a solvent, etc., the total solid concentration is preferably 15% by mass or more, particularly preferably 40% by mass or less, and the viscosity is preferably 50 mPa · s or more, particularly preferably 100 mPa · s. A coating solution for forming a charge transport layer is prepared at s or more, preferably 700 mPa · s or less, particularly preferably 500 mPa · s or less.

  Here, the viscosity of the coating solution is substantially determined by the molecular weight of the binder resin, but as described above, when the molecular weight is too low, the mechanical strength of the photosensitive layer is lowered, so that the binder has a molecular weight that does not impair this. It is preferable to use a resin. A charge transport layer and a photosensitive layer are formed by a dip coating method using the coating solution thus prepared. The polymer of the present invention is particularly excellent in coating performance.

  Thereafter, the coating film is dried, and the drying temperature and drying time are adjusted so that necessary and sufficient drying is performed. A drying temperature is 100-250 degreeC normally, Preferably it is 110-170 degreeC, More preferably, it is the range of 115-140 degreeC. Examples of the drying method include a method using a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer and the like.

In the following, aspects and production methods of the polymerized toner used in the present invention will be described.

  The electrophotographic photosensitive member of the present invention is for developing the electrostatic latent image formed on the electrophotographic photosensitive member using a polymerized toner. Although the polymerized toner has good resolution, the particle diameter is small and the particle shape is close to a spherical shape, so the cleaning member must be brought into strong contact with the electrophotographic photosensitive layer, and therefore contains the specific polymer described above. The effect of the present invention is exhibited only when combined with the photosensitive layer. In addition, since the polymer toner has a small average particle size and a sharp particle size distribution, the image quality is good, and image defects due to repeated use are easily noticeable. Therefore, when combined with the specific electrophotographic photosensitive member described above, a more synergistic effect is obtained. Can demonstrate.

  The polymer toner of the present invention includes those obtained by an emulsion polymerization aggregation method and those obtained by a suspension polymerization method. Further, encapsulated toner as described later is also included. Preferably, it is obtained by an emulsion polymerization aggregation method because the particle size distribution is sharp.

  The toner particles of the present invention preferably have a volume average particle size (hereinafter abbreviated as “Dv”) in the range of 3 μm to 15 μm, particularly preferably in the range of 4 μm to 10 μm. If the volume average particle size is too large, a high-resolution image may not be formed. If it is too small, handling as a powder may be difficult. Further, since the effect of the present invention is more exhibited when the resolution is good and the image defect is conspicuous, the range of 4 μm to 8 μm is further preferable, and the range of 4 μm to 7 μm is even more preferable.

  The particle size distribution of the polymerized toner of the present invention is not particularly limited, but the value Dv / Dn obtained by dividing Dv by the number average particle diameter (hereinafter abbreviated as “Dn”) is preferably 1.3 or less. Is particularly preferably 1.25 or less, and further preferably 1.2 or less. Further, the lower limit value of Dv / Dn is 1, but this means that all the particle sizes are equal, and it is difficult to manufacture or costs too much. Therefore, 1.03 or more is preferable, and 1.05 or more is preferable. Further preferred.

  The volume average particle diameter Dv and the number average particle diameter Dn of the toner in the present invention are defined as those measured using a precision particle size distribution measuring device Coulter Counter Multisizer III manufactured by Beckman Coulter Inc. Specifically, an interface for outputting the number distribution / volume distribution and a general personal computer are connected and used. In addition, Isoton II is used as the electrolytic solution. As a measurement method, 0.1 to 5 mL of alkylbenzene sulfonate as a dispersant is added to 100 to 150 mL of the electrolytic solution, and 2 to 20 mg of a measurement sample (toner) is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and measured with the Coulter Counter Multisizer III type using a 100 μm aperture. In this way, the number and volume of the toner are measured to calculate the number distribution and the volume distribution, respectively, and the volume average particle diameter Dv and the number average particle diameter Dn are obtained, respectively. In the present invention, Dv and Dn are defined as values obtained as described above.

  The toner preferably has few fine particles (fine powder) and coarse powder. When the number of fine particles is small, the fluidity of the toner is improved, and a colorant, a charge control agent, and the like are uniformly distributed, and the chargeability tends to be uniform. In the present invention, measurement of fine particles and coarse powder is performed using a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation, and values such as the number are defined as those obtained.

  In the present invention, it is preferable to use a toner whose measured value (number) of particles of 0.6 μm to 2.12 μm by the above apparatus is 15% or less of the total number of particles. This means that fine particles are less than a certain amount, and it is particularly preferably 10% or less, and further preferably 5% or less. In addition, the lower limit of the measured value (number) of particles of 0.6 μm to 2.12 μm is not particularly limited and is most preferably none at all, but it is difficult to manufacture or too expensive, so 0.5 % Or more is preferable, and 1% or more is particularly preferable. In the case of this range, the effect of the image forming method using the photosensitive layer of the present invention can be exhibited.

  The degree of sphericity of the polymerized toner of the present invention is not particularly limited, but is preferably close to a sphere. Regarding the spherical degree, in the present invention, values of “50% circularity” and “SF-1” defined as follows are used.

<50% circularity>
The “50% circularity” of the polymerized toner indicates the degree of unevenness of the toner particles, and is defined as follows using the measured value with a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation. .
50% circularity = peripheral length of a circle having the same area as the particle projection area / periphery length of the projected particle image The toner particle is 1 when it is a perfect sphere, and the more complicated the surface shape, the smaller the “50% circularity”.

  The specific measurement method is as follows. That is, alkylbenzene sulfonate is added as a dispersant to 20 mL of water from which impurities in the container have been previously removed, and about 0.05 g of a measurement sample (toner) is further added. The suspension in which the sample is dispersed is irradiated with ultrasonic waves for 30 seconds, the dispersion concentration is set to 3.0 to 8.0 thousand pieces / μL, and the above flow type particle image measuring apparatus is used, and the flow type particle image measuring apparatus is used. The circularity distribution of the particles having the equivalent circle diameter is measured.

  In the present invention, the “50% circularity” of the polymerized toner is not particularly limited, but is preferably 0.9 or more. Especially preferably, it is 0.92 or more, More preferably, it is 0.95 or more. In addition, it is difficult to produce a perfect sphere, and considering the cost, it is preferably 0.995 or less, particularly preferably 0.99 or less. The closer it is to a sphere, the less likely it is to localize the charge amount within the individual particles, and the developability tends to be uniform, which is preferable for improving the image quality, but if the toner shape is too close to a perfect sphere. Insufficient cleaning of residual toner after image formation may cause toner to remain on the surface of the electrophotographic photosensitive member and stain the image formed thereafter, resulting in a defect. In such a case, no defective cleaning will occur. As a result, it is necessary to perform strong cleaning, and as a result, the electrophotographic photosensitive member is likely to be worn or damaged due to the strong cleaning, which may shorten the life of the electrophotographic photosensitive member. In addition, when the 50% circularity is too small, the cleaning characteristics are relatively good, and it is not necessary to bring the cleaning member into strong contact with the electrophotographic photosensitive member. Therefore, the effect of using the photosensitive layer using the polymer of the present invention. May not be possible.

<SF-1>
“SF-1” of the polymerized toner indicates the degree of roundness of the toner particles. For each toner, a plurality of 1000 × photographs are taken with a scanning electron microscope (SEM), and randomly. Image analysis of 100 selected toner particles is performed by Luzex-F (manufactured by Nireco), and is defined as a value calculated from the following equation.
SF-1 = ((maximum particle diameter length of particle projection image) ² / particle projection area) × (π / 4) × 100
When the toner is a perfect sphere, SF-1 is 100, and the more the toner is distorted, the larger SF-1.

  In the present invention, SF-1 of the polymerized toner is not particularly limited, but is preferably 140 or less. Especially preferably, it is 120 or less. As SF-1 is smaller, the charge amount is less likely to be localized within the individual particles, and the developability tends to be uniform. When SF-1 is in the above range, the toner surface is relatively smooth, the toner charging characteristics are further improved, and a higher effect can be obtained with respect to the problems of the present invention. Further, when SF-1 is too large, the cleaning characteristics are relatively good, so that it is not necessary to bring the cleaning member into strong contact with the electrophotographic photosensitive member, and the effect of using the photosensitive layer of the present invention may not be exhibited. .

  As the polymerized toner of the present invention, any of black toner, color toner, and full color toner can be used, but when used as a color toner or full color toner, the effects of the present invention can be exhibited more remarkably. In addition, as the polymerized toner of the present invention, any of a non-magnetic one-component developing toner, a magnetic one-component developing toner, and a two-component developing toner can be used. This is preferable because the effects of the present invention can be remarkably exhibited.

<Emulsion polymerization aggregation method>
One form of the polymerized toner of the present invention is obtained by an emulsion polymerization aggregation method. The emulsion polymerization aggregation method is not particularly limited as long as the particles obtained by emulsion polymerization are further agglomerated to produce a toner, but the polymer primary particles in an aqueous medium containing a polymerization initiator and an emulsifier. First, an emulsion of the polymer primary particles is prepared by emulsifying the polymerizable monomer constituting the polymer, and the polymerizable monomer is polymerized with stirring, and then a colorant and, if necessary, the resulting polymer primary particle emulsion. A method in which a charge control agent, a release agent, and the like are blended to aggregate the primary polymer particles to form primary particle aggregates, and the primary particle aggregates are further aged by heating is preferable.

  The polymerizable monomer constituting the polymer primary particle is not limited, and examples thereof include styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene. Styrenes; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-methacrylic acid n- (Meth) acrylic acid esters such as butyl, isobutyl methacrylate, hydroxyethyl methacrylate, ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropyla Riruamido, N, acrylamides such as N- dibutyl acrylamide. Among these styrene, butyl acrylate are particularly preferred. These polymerizable monomers may be used alone or in combination.

  Furthermore, a polyfunctional monomer can also be used as the polymerizable monomer constituting the polymer primary particles. Examples of the multifunctional monomer include divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. It is also possible to use monomers having a reactive group in the pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein and the like. Among these, radical polymerizable bifunctional monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable. These polyfunctional monomers may be used alone or in combination.

  When a polyfunctional monomer is used as the polymerizable monomer constituting the polymer primary particles, the content thereof is preferably 0.005 parts by weight or more with respect to 100 parts by weight of the total monomers constituting the polymer primary particles, More preferably, it is 0.1 parts by weight or more, more preferably 0.3 parts by weight or more, preferably 5 parts by weight or less, more preferably 3 parts by weight or less, still more preferably 1 part by weight or less. By using the polyfunctional monomer as described above, the offset property with respect to the heat fixing roller may be improved at the time of fixing.

  Examples of the polymerization initiator include persulfates such as sodium persulfate and ammonium persulfate; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide; hydrogen peroxide and the like Inorganic peroxides and the like can be mentioned, and these are used singly or in combination. Of these, inorganic peroxides are preferable. The polymerization initiator is usually used in an amount of 0.05 to 2 parts by weight with respect to 100 parts by weight of the polymerizable monomer. These polymerization initiators include one or more reducing organic compounds such as ascorbic acid, tartaric acid and citric acid; and reducing inorganic compounds such as sodium thiosulfate, sodium bisulfite and sodium metabisulfite. The redox initiator used in combination can also be suitably used.

  Moreover, a well-known chain transfer agent can also be used as needed, Specifically, t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane, etc. are mentioned. The chain transfer agent may be used alone or in combination of two or more, and is usually used in a range of 5% by mass or less with respect to all monomers.

  As the emulsifier, a nonionic, anionic, cationic or amphoteric surfactant is usually used. Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyalkylene alkyl phenyl ethers such as polyoxyethylene octylphenyl ether, and sorbitan fatty acid esters such as sorbitan monolaurate. Examples of the anionic surfactant include fatty acid salts such as sodium stearate and sodium oleate, alkylaryl sulfonates such as sodium dodecylbenzene sulfonate, and alkyl sulfate salts such as sodium lauryl sulfate. Examples of the cationic surfactant include amphoteric surfactants such as alkylamines such as laurylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride. Is, for example, alkyl betaines such as lauryl betaine, and the like, or those of one or two is used. Of these, nonionic surfactants and anionic surfactants are preferred. The amount used as an emulsifier is usually 1 to 10 parts by weight per 100 parts by weight of the polymerizable monomer, and these emulsifiers include, for example, partially or fully saponified polyvinyl alcohols such as saponified polyvinyl alcohol, hydroxyethyl cellulose. 1 type, or 2 or more types, such as cellulose derivatives, etc. can be used together as a protective colloid.

  In addition, the addition of the polymerizable monomer to the reaction system in the emulsion polymerization may be any of batch addition, continuous addition, and intermittent addition, but continuous addition is preferable from the viewpoint of reaction control. Moreover, when using a some monomer, the addition of each monomer may be added separately, or a plurality of monomers may be mixed and added simultaneously. Furthermore, it is possible to change the monomer composition during the monomer addition. The addition of the emulsifier to the reaction system may be any of batch addition, continuous addition, and intermittent addition.

  In addition to the emulsifier and the polymerization initiator, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, and the like can be appropriately added to the reaction system.

  As the polymer primary particles, one kind of polymer primary particles obtained as described above can be used, and a plurality of different polymer primary particles obtained as described above can be used in combination. Moreover, the polymer primary particle can use together the particle | grains obtained by the other polymerization method with what was obtained by the said emulsion polymerization. Examples of such particles include, in addition to particles having the same composition as that obtained by emulsion polymerization, vinyl monomers such as vinyl acetate, vinyl chloride, vinyl alcohol, vinyl butyral, and vinyl pyrrolidone. Homopolymer or copolymer; thermoplastic resin such as saturated polyester resin, polycarbonate resin, polyamide resin, polyolefin resin, polyarylate resin, polysulfone resin, polyphenylene ether resin; unsaturated polyester resin, phenol resin, epoxy resin, urethane resin And particles composed of a thermosetting resin such as rosin-modified maleic acid resin, and two or more of these may be used in combination.

  The volume average particle size of the polymer primary particles is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, usually 3 μm or less, preferably 2 μm or less, more preferably 1 μm or less. It is desirable. The volume average particle size is measured using a Nikkiso Microtrac UPA. When the particle size is less than the above range, it may be difficult to control the aggregation rate. When the particle size exceeds the above range, the particle size of the toner obtained by aggregation tends to be large, and a toner having a target particle size can be obtained. It can be difficult.

The volume particle size distribution such as the volume average particle size of the polymer primary particles is measured by a dynamic light scattering method. This method obtains the particle size distribution by detecting the speed of Brownian motion of finely dispersed particles, irradiating the particles with laser light, and detecting light scattering (Doppler shift) with different phases according to the speed. It is. In actual measurement, the above volume particle size was set to the following setting using an ultrafine particle size distribution measuring apparatus using a dynamic light scattering method (manufactured by Nikkiso Co., Ltd., UPA-EX150, abbreviated as “UPA”). To do.
Measurement upper limit: 6.54 μm
Measurement lower limit: 0.0008 μm
Number of channels: 52
Measurement time: 100 sec.
Particle permeability: Absorption
Particle refractive index: N / A (not applicable)
Particle shape: Non-spherical
Density: 1 g / cm ³
Dispersion medium type: WATER
Dispersion medium refractive index: 1.333
At the time of measurement, measurement is performed with a sample in which a dispersion of particles is diluted with a liquid medium so that the sample concentration index is in the range of 0.01 to 0.1 and is dispersed with an ultrasonic cleaner. The volume average particle diameter according to the present invention is measured by using the result of the volume particle size distribution as an arithmetic average value.

  The polymer primary particles have a glass transition temperature of preferably 40 ° C. or higher, more preferably 50 ° C. or higher, preferably 80 ° C. or lower, more preferably 70 ° C. or lower. When the glass transition temperature is within the above range, it is desirable because the storage stability and fixing property of the toner are improved. Here, the glass transition temperature is obtained by drawing a tangent to a transition (inflection) start portion of a curve measured at a temperature rising rate of 10 ° C./min in a differential scanning calorimeter (DTA-40 manufactured by Shimadzu Corporation). It can be determined as the temperature at the intersection of tangents.

  Further, the polymer primary particles have at least one of the peak molecular weights in gel permeation chromatography, preferably 3000 or more, more preferably 10,000 or more, further preferably 30,000 or more, preferably 100,000 or less, more Preferably it is 70,000 or less, more preferably 60,000 or less. When the peak molecular weight is in the above range, it is desirable because the durability, storage stability, and fixability of the toner are improved. Here, as the peak molecular weight, a value converted to polystyrene is used, and components insoluble in a solvent are excluded in measurement.

  The colorant is not limited, and various inorganic and organic dyes and pigments generally used as a toner colorant are used. Specifically, for example, iron powder, copper powder, etc. Metal powders; metal oxides such as Bengala; inorganic pigments such as carbons represented by carbon black such as furnace black and lamp black; azo series such as benzidine yellow and benzidine orange; quinoline yellow, acid green, and alkali blue Precipitates with dye precipitants such as dyes, acid dyes such as rhodamine, magenta, and macalite green dyes, tannic acid, precipitates with phosphomolybdic acid, etc., basic dyes, mordant dyes such as metal salts of hydroxyanthraquinones, Phthalocyanine series such as phthalocyanine blue and copper phthalocyanine sulfonate, quinacridone Quinacridone and dioxane organic pigments such as quinacridone violet, aniline black, azo dyes, naphthoquinone dyes, indigo dyes, nigrosine dyes, phthalocyanine dyes, polymethine dyes, di- and triallylmethane dyes and the like These two or more types can be used in combination. The content ratio of the colorant is preferably 1 to 20 parts by weight, particularly preferably 2 to 15 parts by weight, based on 100 parts by weight of the polymer primary particles.

For the toner of the present invention, a magnetic colorant may be used as long as the characteristics are not lost. Examples of the magnetic colorant include a ferromagnetic material exhibiting ferrimagnetism or ferromagnetism at a use environment temperature of a copying machine or the like, specifically, for example, magnetite (Fe ₃ O ₄ ), maghematite ( γ-Fe ₂ O ₃ ), an intermediate or mixture of magnetite and maghematite; ferrite (M _x Fe _{3 -x} O ₄ ; where M is Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd spinel ferrites etc.), _{etc., BaO · 6Fe 2 O 3,} SrO · 6Fe 2 O 3 or the like hexagonal _{ferrite; Y 3 Fe 5 O 12,} Sm 3 Fe 5 O garnet-type oxides such as _{12; two} such CrO Rutile type oxides: Metals such as Cr, Mn, Fe, Co, and Ni, or their ferromagnetic alloys, etc. include those exhibiting magnetism in the vicinity of 0 to 60 ° C. Among them, magnetite and the like are preferable. When blended from the viewpoint of preventing scattering and charging control while having the characteristics as a non-magnetic toner, the blending amount is 0.1 to 10 parts by weight, preferably 100 parts by weight of the polymer primary particles. The amount is preferably 0.2 to 8 parts by weight, more preferably 0.5 to 5 parts by weight.

  The polymerized toner of the present invention preferably contains a charge control agent. Examples of the charge control agent include conventionally known dyes such as nigrosine dyes, quaternary ammonium salt compounds, and triphenylmethane compounds. And positively chargeable charge control agents such as imidazole compounds and polyamine resins. In addition, metal-containing azo dyes such as chromium, cobalt, aluminum and iron; metal salts and metal complexes of salicylic acid or alkylsalicylic acid such as chromium, zinc and aluminum; metal salts and metal complexes of benzylic acid; amide compounds, phenolic compounds, Examples include negatively charged charge control agents such as naphthol compounds and phenolamide compounds. The content ratio of the charge control agent is preferably 0.01 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the polymer primary particles.

  The polymerized toner of the present invention preferably further contains a release agent for improving the releasability at the time of fixing to a transfer material, and as the release agent, a conventionally known, for example, Polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight ethylene-propylene copolymers; fluororesin waxes such as low molecular weight polytetrafluoroethylene; paraffin waxes: stearic acid ester, behenic acid ester, montanic acid ester Such as ester waxes having long chain aliphatic groups such as hydrogenated castor oil and carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; silicones having alkyl groups; higher grades such as stearic acid Fatty acids; Long chain fatty alcohols; Polyhydric alcohols such as pentaerythritol and long chain fats (Partial) ester of an acid; oleic acid amide, waxes such as higher fatty acid amides such as stearic acid amide. As these release agents in the present invention, those having a melting point of 50 to 100 ° C. are preferable from the viewpoint of low-temperature fixing and high-speed fixing.

  The release agent can also be used as a seed in emulsion polymerization of the polymerizable monomer to perform seed polymerization, thereby producing polymerizable primary particles containing the release agent. The content ratio of the release agent is preferably 0.1 to 30 parts by weight, more preferably 5 to 25 parts by weight with respect to 100 parts by weight of the polymerizable primary particles.

  Further, the toner contains various known internal additives such as silicone oil and silicone varnish for the purpose of modifying the adhesiveness, cohesiveness, fluidity, chargeability, surface resistance, etc. of the toner. Also good. These can be added internally to the toner particles by adding at the time of aggregation, but are preferably contained in the polymer primary particles in advance.

  The production of toner particles by the emulsion polymerization aggregation method is performed by adding a colorant and, if necessary, additives such as a charge control agent and a release agent to the emulsion of the polymer primary particles obtained by the emulsion polymerization. Next, while stirring and mixing with a disperser, a mixer, etc., for example, heating, electrolyte addition, pH adjustment, curing agent addition, etc., reduce the dispersion stability of the polymer primary particles as an emulsion, and aggregate the primary particles The treatment is performed to form aggregates, and then primary particles in the aggregates are aged (fused) and stabilized by heat treatment.

As an electrolyte in the case of performing aggregation by adding an electrolyte, any of organic salts and inorganic salts may be used. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , _{MgCl 2, CaCl 2, MgSO 4} , CaSO 4, ZnSO 4, Al 2 (SO 4) 3, Fe 2 (SO 4) 3, CH 3 COONa, C 6 H 5 SO 3 Na and the like. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred. The amount of the electrolyte to be added varies depending on the type of the electrolyte, but is usually 0.05 to 25 parts by weight, preferably 0.1 to 15 parts by weight, and more preferably 0.8 to 100 parts by weight of the solid component of the mixed dispersion. 1 to 10 parts by weight. In the case of agglomerating by adding an electrolyte, if the amount of electrolyte added is less than the above range, the agglomeration reaction proceeds slowly, and fine particles of 1 μm or less remain after the agglomeration reaction, or the obtained particle agglomerates If the average particle size of the particles does not reach the target particle size, the average particle size of the particles may exceed the above range. Problems such as inclusion of powder or irregular shapes may occur. In addition, 20-40 degreeC is preferable and the aggregation temperature in the case of performing aggregation by adding electrolyte has more preferable 25-35 degreeC.

  The heating temperature at the time of fusing and stabilizing the primary particles in the aggregate is preferably not less than the glass transition temperature of the polymer constituting the primary particles, more preferably not less than 5 ° C. higher than the glass transition temperature. Moreover, the temperature below 80 degreeC higher than the glass transition temperature of a polymer is preferable, and the temperature below 50 degreeC is still more preferable. The heating time is preferably 1 to 6 hours. By such heat treatment, the primary particles in the aggregate are fused and integrated, and the shape of the toner particles as the aggregate is also nearly spherical.

<Suspension polymerization method>
Another form of the polymerized toner of the present invention is obtained by a suspension polymerization method. The suspension polymerization method is not particularly limited as long as the toner particles are directly obtained by suspension polymerization, and examples thereof include a method described in JP-A-10-269501.

  In the suspension polymerization method, a polymerization initiator, a colorant, a charge control agent, a release agent and the like are mixed with a polymerizable monomer, and dispersion treatment is performed using a disperser such as a disperser. In a water-miscible medium using an appropriate stirrer, and granulated to a toner particle size, and then a polymerizable monomer is polymerized to produce a toner.

  The polymerizable monomer, acidic monomer, basic monomer, polyfunctional monomer, chain transfer agent, colorant, magnetic colorant, charge control agent, release agent, etc. used in the suspension polymerization method are the emulsion polymerization described above. The thing similar to what is used by the aggregation method is used. The same applies to preferable ones, and the same applies to preferable contents and the like.

  When a suspension stabilizer is used in the production of the toner by the suspension polymerization method, it is preferable to select one that exhibits neutrality or alkalinity in water that can be easily removed by acid washing after the polymerization. Further, it is preferable to select a toner that can obtain a toner having a narrow particle size distribution. Suspension stabilizers that satisfy these requirements include calcium phosphate, tricalcium phosphate, magnesium phosphate, calcium hydroxide, magnesium hydroxide, and the like. Each can be used alone or in combination of two or more. These suspension stabilizers can be used in the range of 1 to 10 parts by weight with respect to the entire polymerizable monomer.

  Examples of the polymerization initiator used in the suspension polymerization method include the same ones as used in the emulsion polymerization aggregation method described above, and further, 2,2′-azobisisobutyronitrile, Examples also include 2'-azobisiso (2,4-dimethyl) valeronitrile, benzoyl peroxide, lauroyl peroxide, and the like. Of these, azo polymerization initiators are preferred in the suspension polymerization method.

<Common to emulsion polymerization aggregation method and suspension polymerization method>
As described above, the toner particles obtained by the emulsion polymerization aggregation method and the toner particles obtained by the suspension polymerization method are further polymerized, polymer emulsion, colorant dispersion, charge control agent dispersion, wax dispersion. A toner having a capsule structure may be formed by forming the outer layer by coating the toner surface with a liquid or the like. The thickness of the outer layer in that case is not particularly limited, but is preferably 0.01 μm to 0.5 μm. The glass transition temperature of the polymer used in the outer layer and the polymer of the emulsion is preferably in the range of 70 to 110 ° C., and preferably higher than the glass transition temperature of the toner particles. The outer layer is preferably formed by a method such as a spray drying method, an in-situ method, or a liquid particle coating method.

  The polymerized toner of the present invention contains externally added fine particles on the surface of toner particles. As the externally added fine particles, known inorganic or organic fine particles may be used, which may be negatively charged or positively charged, and these may be used in combination.

  Examples of the negatively charged externally added fine particles include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc, and hydrotalcite; calcium titanate, strontium titanate, Examples thereof include inorganic fine particles such as metal titanates such as barium titanate; nitrides such as titanium nitride and silicon nitride; carbides such as titanium carbide and silicon carbide. In addition, acrylic acid resin having acrylic acid or its derivative as the main component of monomer, methacrylic acid resin having methacrylic acid or its derivative as the main component of monomer, tetrafluoroethylene resin, trifluoroethylene resin, Organic fine particles such as polyvinyl chloride, polyethylene, polyacrylonitrile and the like can be mentioned. Among the inorganic fine particles, silica, titania, alumina and the like are preferable, and those treated with a silane coupling agent or silicone oil are more preferable. As the organic fine particles, acrylic resin such as polymethyl acrylate, methacrylic resin such as polymethyl methacrylate, and the like are preferable, and polymethyl methacrylate is particularly preferable.

  Examples of the positively charged externally added fine particles include calcium phosphate compounds such as tricalcium phosphate, calcium dihydrogen phosphate, calcium monohydrogen phosphate, and substituted calcium phosphate in which a part of phosphate ion is substituted by an anion or Examples thereof include those whose surface has been subjected to a hydrophobic treatment with fatty acid or the like; silica or alumina which has been subjected to a surface treatment such as aminosilane treatment.

  The externally added fine particles preferably have an average particle diameter of preferably 0.001 μm or more, more preferably 0.005 μm or more, preferably 1 μm or less, more preferably 0.5 μm or less. Further, a plurality of externally added fine particles having different materials and different average particle diameters can be blended.

  The content of the externally added fine particles is 0.5% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and 3.5% by mass or less with respect to the toner finally obtained. , Preferably 3% by mass or less, more preferably 2.5% by mass or less. By attaching the externally added fine particles having such a content to the surface of the toner particles, the low-temperature fixability and the offset resistance are improved, and high-speed printing becomes possible. Although this mechanism is not clear, it is presumed that the externally added fine particles do not physically inhibit the adhesion between the melted toner and the printing paper or the like if the adhesion amount of the externally added fine particles is in the above range.

  Further, by not attaching an excessive amount of externally added fine particles, it is possible to suppress a decrease in the conduction efficiency of the heat received by the toner from the heating roller during fixing, so that the toner can be melted quickly, for example, the printing speed is 100 mm / It is considered that fixing can be suitably performed even under high-speed printing conditions of 200 mm / sec or more, particularly at least 200 mm / sec. In addition, when the content of the externally added fine particles is less than the above range, image defects such as blurring of a solid image may occur due to deterioration of toner fluidity. Here, the content of the externally added fine particles does not mean only the externally added fine particles attached to the surface of the toner particles, but the externally added fine particles that are not attached and exist independently or the surface of the toner particles. It also includes externally added fine particles buried in the vicinity.

  A method for blending (attaching) the externally added fine particles on the surface of the toner particles is not limited, and a mixer generally used for toner production can be used. For example, a Henschel mixer, a V-type blender, a Redige mixer, etc. It is made by stirring and mixing uniformly with a mixer.

  The chargeability of the polymerized toner of the present invention thus obtained is not limited, but in the case of a negatively chargeable toner, the charge amount at 23 ° C. and 50% relative humidity is preferably −10 μC / g or less, more preferably Is −20 μC / g or less, preferably −90 μC / g or more, more preferably −70 μC / g or more. When the toner is positively charged, the charge amount at 23 ° C. and 50% relative humidity is preferably +10 μC / g or more, more preferably +15 μC / g or more, preferably +50 μC / g or less. Preferably it is +30 μC / g or less.

  In the present invention, the toner charge amount is measured by first weighing 19.2 g of a non-coated ferrite carrier (P100 manufactured by Powdertech) and 0.8 g of particles to be measured, and stirring for 5 minutes with a reciprocating shaker (stir strength 500 rpm). ) And then measured with a blow-off measuring device (manufactured by Toshiba Chemical).

  When the toner of the present invention has a charge amount in the above range, it is preferable because the image quality is low and the image quality is high. The charge amount of the toner can be adjusted by selecting a resin as a main component of the developer, a charge control agent added if necessary, an externally added fine particle or the like, or a blending ratio, blending method or adhesion method thereof. In particular, it is effective to select the externally added fine particles and optimize the adhesion amount.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member and polymerized toner of the present invention will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6, and a fixing device as necessary. A device 7 is provided.

  The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. However, a corona charging device such as a corotron or a scorotron, a contact charging device such as a charging brush, or the like is also used. Since the electrophotographic photosensitive member of the present invention is excellent in durability, it is preferably used for charging by a contact charging member. Among these, the electrophotographic photosensitive member of the present invention is less in that the electrophotographic photosensitive member is less worn. For the charging, a roller-shaped charging device having a roller-shaped contact charging member as shown in FIG. 2 is preferable.

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge including both of them (hereinafter, also referred to as “photosensitive cartridge”). Yes. For example, when the electrophotographic photoreceptor 1 or the charging device 2 is deteriorated, the photoreceptor cartridge can be detached from the image forming apparatus main body, and another new photoreceptor cartridge can be mounted on the image forming apparatus main body. It has become. Also, in many cases, toner is stored in a toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is formed into an image. It can be removed from the main body and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include lasers such as halogen lamps, fluorescent lamps, semiconductor lasers, and He—Ne lasers; LEDs and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a wavelength shorter than 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and any device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. Since the electrophotographic photosensitive member of the present invention is excellent in durability, the developing device uses a developing roller placed in contact with the electrophotographic photosensitive member or a magnetic brush that rubs the surface of the electrophotographic photosensitive member. Demonstrate the effect. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and is configured to store toner T inside the developing tank 41. Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. This replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The restricting member 45 is formed of a resin blade such as silicon resin or urethane resin; a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with a resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

  The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, the transfer device 5 is composed of a transfer charger, a transfer roller, a transfer belt, and the like disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  The cleaning device 6 scrapes the residual toner adhering to the photoconductor 1 with a cleaning member and collects the residual toner. When the residual toner adhering to the photoconductor 1 is small or absent, As long as the image is not affected, the cleaning device 6 may be omitted. There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. In the present invention, since polymerized toner is used, the condition for scraping off by the cleaning member becomes strong, and the load on the photoreceptor 1 may increase.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 are known heat fixing members such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which polytetrafluoroethylene resin is coated, and a fixing sheet. Can be used. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.

  The type of the fixing device is not particularly limited, and a fixing device of an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

<Recording images>
In the image forming apparatus using the electrophotographic photosensitive member configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage. What is charged by a direct current voltage is preferable in that mechanical vibration is small. Further, contact charging, particularly roller contact charging is preferable because the above-described effects of the electrophotographic photosensitive member of the present invention can be further exhibited.

  Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1. The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.

  When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6. After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

  Even when an electrophotographic photosensitive member using a polymer comprising a repeating unit containing a partial structure represented by the formula (1) is developed using a polymerized toner, the action / principle showing excellent durability is Although it is not clear, it is considered that the stacking structure of the polymer chain of the polymer is caused. In addition, a large amount of the compatible charge transport material generally decreases the strength, but it is considered that such a polymer has less influence.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these unless it exceeds the gist. In the examples, “parts” indicates “parts by weight” unless otherwise specified, and “%” indicates “mass%” unless otherwise specified.

Example 1
<Creation of photosensitive drum A>
In X-ray diffraction by CuKα characteristic X-ray, 10 parts of oxytitanium phthalocyanine showing a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° and 150 parts of 1,2-dimethoxyethane are mixed, and A pigment dispersion was prepared by pulverizing and dispersing with a sand grind mill. Further, 5 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name Denkabutyral # 6000C) and 95 parts of 1,2-dimethoxyethane were mixed to prepare a binder resin solution having a solid content concentration of 5%.

  160 parts of the pigment dispersion prepared above, 100 parts of the binder resin solution, an appropriate amount of 1,2-dimethoxyethane, and an appropriate amount of 4-methoxy-4-methyl-2-pentanone are mixed to obtain a solid content concentration of 4.0. %, 1,2-dimethoxyethane: 4-methoxy-4-methyl-2-pentanone = 9: 1 (mass ratio).

  Next, the surface of a cylinder made of an aluminum alloy having an outer diameter of 30 mm, a length of 351 mm, and a wall thickness of 1.0 mm, which is mirror-finished, is subjected to anodizing treatment, and then a sealing agent mainly composed of nickel acetate. By performing sealing treatment, an anodic oxide coating (alumite coating) of about 6 μm was formed.

  Next, this cylinder was dip-coated in the previously prepared dispersion for forming a charge generation layer, and a charge generation layer was formed so that the film thickness after drying was about 0.4 μm.

  Next, the cylinder in which the charge generation layer is formed is a polycarbonate (viscosity average molecular weight of about 30000) consisting of 50 parts of a charge transport material represented by the following formula (a) and a repeating unit represented by the formula (2) as a binder resin. 100 parts of a mixed solvent of tetrahydrofuran: toluene = 80: 20 (mass ratio) was mixed by dipping in a coating solution for forming a charge transport layer to form a charge transport layer having a thickness of 18 μm after drying. . The dispersion for forming a charge transport layer coating had high viscosity stability and was able to form a good charge transport layer free from unevenness, twist, film thickness fluctuation, and the like. The product thus obtained is referred to as “photosensitive drum A”.

<Creation of photosensitive drum B>
A photoconductor drum B was prepared in the same manner as the photoconductor drum A, except that the polycarbonate used for the preparation of the photoconductor drum A was a polycarbonate represented by the following formula (8).

<Creation of polymerization toner>
1000 parts of cyan base toner prepared by the emulsion polymerization aggregation method and containing as a main component a copolymer of styrene and n-butyl acrylate having a molar ratio of 77/23 (peak molecular weight of 30,000), externally added fine particles As a result, 20 parts of the following silica 1 and 5 parts of the following silica 2 were mixed in a Henschel mixer manufactured by Mitsui Mining Co., Ltd. to prepare a polymerized toner for this evaluation.
Silica 1: Hexamethyldisilazane treatment, primary particle size about 30nm
Silica 2: treated with dimethylpolysiloxane, primary particle size of about 7 nm

  The polymerization toner had a Dv of 7.3 μm and a Dn of 6.4 μm. The 50% circularity was 0.96 and SF-1 was 136.

<Making pulverized toner>
Using a binder polymer having the same composition and molecular weight as in the preparation of the polymerized toner, the color pigments and the like were the same, and a pulverized toner was prepared according to a conventional method. The pulverized toner had a Dv of 8.1 μm and a Dn of 6.3 μm. The 50% circularity was 0.90 and SF-1 was 154. The glass transition temperature was 62.5 ° C. like the polymerized toner.

Evaluation Examples 1 to 4
<Image evaluation by image forming apparatus>
<< Measurement of fog value on drum >>
The photoconductor drums A to F are mounted on a cartridge of a commercially available printer (ML9300 manufactured by Oki Data Co., Ltd.), and the above polymerized toner is put in the cartridge, and in a LL (5 ° C., 10% RH) environment, 1 Image formation of 14,000 sheets intermittently was performed. A solid image and a memory confirmation image were printed every 1000 sheets printed from the beginning of image formation. The ML9300 manufactured by Oki Data Co., Ltd. used for the evaluation includes a roller-shaped contact charging member that is placed in contact with the electrophotographic photosensitive member to which a DC voltage is applied, and is exposed by an LED having a wavelength of 760 nm. A tandem-type full-color image forming apparatus that develops with a developing device having a developing roller disposed in contact therewith.

  The evaluation of fog on the drum was performed by attaching a transparent adhesive tape to the surface of the photosensitive drum after printing a white solid image so that there was no air bubble between the photosensitive drum and peeling off the tape. Next, using a Macbeth densitometer (Mac920 RD920), the optical density was measured from above the attached transparent adhesive tape. The optical density was measured in the same manner for a simple adhesive tape simply pasted on a white paper, and the difference was defined as the fog value on the drum. For the fog value on the drum, the above operation was performed every 1000 sheets printed from the initial stage of image formation, and this operation was performed until after 14,000 sheets were printed.

<< Measurement of memory value >>
The memory image is evaluated by measuring the density (hereinafter referred to as H1) after the halftone image is formed, and then the memory confirmation image (the solid circle is at the top of the image and the background is the halftone). The density of the drum cycle (94.2 mm) position (hereinafter referred to as H2) was measured using the solid circle as the starting point, and the absolute value of the difference between H1 and H2 was used as the memory value. Similarly to the on-drum fog value, the memory value was measured from the initial image formation until every 1000 sheets were printed and after a maximum of 14,000 sheets were printed. The larger the fog value on the drum and the memory value, the worse the image. Moreover, if the numerical value (difference between H1 and H2) shown here exceeds 0.05, it can be recognized as a visually obvious difference.

  Photosensitive drum A and photosensitive drum B were evaluated using the above polymerized toner and pulverized toner. The results are shown in Tables 1 and 2. Here, K represents 1000.

Image evaluation result by image forming device (fogging value on drum)

Image evaluation result by image forming device (memory value)

  From the results shown in Table 1, when evaluated using polymerized toner, the photosensitive drum A in Evaluation Example 1 shows a change in fog value on the drum after printing for 14,000 sheets from the initial stage. It was smaller than the body drum B, and it was found that good image quality was obtained even after long-term use. In addition, when the memory values in Table 2 were also evaluated using polymerized toner, the photosensitive drum A in Evaluation Example 1 compared to the photosensitive drum B in Evaluation Example 2 even after printing 14,000 sheets. , Still found small. That is, when evaluated using a polymerized toner, the photosensitive drum A exhibited good durability with few image defects during repeated use.

  Evaluation examples 3 and 4 were evaluated using pulverized toner, but the resolution of the image itself was higher than that evaluated using the polymerized toners of evaluation examples 1 and 2. It was inferior. The photosensitive drum A of Evaluation Example 1 was able to obtain high-resolution image quality, and the image defects were not noticeable after 14,000 sheets were printed even under this severe condition of high resolution.

  As can be seen from Tables 1 and 2, in Evaluation Example 3 and Evaluation Example 4, when the durability evaluation was performed using the pulverized toner, the fog value on the drum and the memory value were not greatly deteriorated in the first place. That is, from this, it is understood that the durability improvement which is the subject of the present invention is necessary only when the polymerized toner is used. It has been found that the problem can be solved by the photosensitive drum A using the specific polymer of the present invention. It has been found that the photosensitive drum A exhibits a particular effect on durability only when a polymerized toner is used, even though the effect is not exhibited when the pulverized toner is used. From this, a synergistic effect by combining the polymerization toner development and the electrophotographic photoreceptor of the present invention was recognized. It has been found that, for the first time, the problems of the present invention can be solved.

Example 2
<Creation of photosensitive drum C>
In X-ray diffraction by CuKα characteristic X-ray, 10 parts of oxytitanium phthalocyanine showing a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° and 150 parts of 1,2-dimethoxyethane are mixed. A pigment dispersion was prepared by pulverizing and dispersing with a sand grind mill. Further, 5 parts of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name Denkabutyral # 6000C) and 95 parts of 1,2-dimethoxyethane were mixed to prepare a binder resin solution having a solid content concentration of 5%.

  160 parts of the pigment dispersion prepared above, 100 parts of the binder resin solution, an appropriate amount of 1,2-dimethoxyethane, and an appropriate amount of 4-methoxy-4-methyl-2-pentanone are mixed to obtain a solid content concentration of 4.0. %, 1,2-dimethoxyethane: 4-methoxy-4-methyl-2-pentanone = 9: 1 (mass ratio).

  On the other hand, the surface of a cylinder made of an aluminum alloy having an outer diameter of 30 mm, a length of 351 mm, and a wall thickness of 1.0 mm is mirror-finished and then anodized, and then sealed with a sealing agent mainly composed of nickel acetate. By performing the hole treatment, an anodic oxide coating (alumite coating) of about 6 μm was formed.

  Next, this cylinder was dip-coated in the previously prepared dispersion for forming a charge generation layer, and a charge generation layer was formed so that the film thickness after drying was about 0.4 μm.

  Next, the cylinder in which this charge generation layer is formed is a polycarbonate composed of only a repeating unit represented by the formula (2) as a charge transport material represented by the above formula (a) and a binder resin, and has a viscosity average molecular weight of about A film after dip coating in a coating solution for forming a charge transport layer prepared by mixing 100 parts of a polymer of 50,000 and a mixed solvent of tetrahydrofuran: toluene = 80: 20 (mass ratio) and drying A charge transport layer having a thickness of 18 μm was formed to obtain a photoreceptor drum C.

  The dispersion for coating and forming the charge transport layer for the photosensitive drum C had high viscosity stability, and was able to form a good charge transport layer free from unevenness, twist, film thickness fluctuation, and the like.

<Create toner>
1000 parts of cyan base toner prepared by the emulsion polymerization aggregation method and containing as a main component a copolymer of styrene and n-butyl acrylate having a molar ratio of 77/23 (peak molecular weight of 30,000), externally added fine particles As a result, 20 parts of the following silica 1 and 5 parts of the following silica 2 were mixed in a Henschel mixer manufactured by Mitsui Mining Co., Ltd. to prepare a toner for this evaluation.
Silica 1: Hexamethyldisilazane treatment, primary particle size about 30nm
Silica 2: treated with dimethylpolysiloxane, primary particle size of about 7 nm

  The toner had a Dv of 7.3 μm and a Dn of 6.4 μm. The glass transition temperature was 62.5 ° C.

<Measurement of film loss by printing durability test>
Next, the photosensitive drum C is mounted on a cartridge of a commercially available printer (ML9300 manufactured by Oki Data Co., Ltd.), and is incorporated as a cyan cartridge using the above polymerized toner, under an NN environment (25 ° C. 30000 prints at 50% relative humidity). At this time, the film thickness of the photosensitive layer before printing was measured with a micrometer for every 10,000 prints, the film reduction amount was calculated from the difference, and evaluation was performed according to the following criteria.

The criteria for “evaluation” are as follows:
◎: Membrane loss is very small and durability is good ○: Membrane loss is small and durability is good ×: Membrane reduction is large and durability is poor

  Similarly, a printing durability test was performed using a commercially available printer (ML9300 manufactured by Oki Data Corporation). The amount of film reduction after printing 10,000 sheets is 0.42 μm, the amount of film reduction after printing 20,000 sheets is 0.75 μm, both of which are less than 1 μm, and extremely excellent in durability. Evaluation was (double-circle).

Example 3
<Manufacture of developing toner A>
Preparation of wax / long chain polymerizable monomer dispersion A1
Paraffin wax (Nippon Seiki Co., Ltd. HNP-9, surface tension 23.5 mN / m, melting point 82 ° C., heat of fusion 220 J / g, melting peak half width 8.2 ° C., crystallization peak half width 13.0 ° C.) 27 Parts (540 g), stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 2.8 parts, 20 mass% sodium dodecylbenzenesulfonate aqueous solution (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A, hereinafter abbreviated as “20% DBS aqueous solution” as appropriate) 1.9 parts and 68.3 parts of demineralized water were heated to 90 ° C. and stirred with a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.) at a rotation speed of 8000 rpm for 10 minutes.

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressurized condition of about 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). The volume average particle size is dispersed to 250 nm while measuring with “Microtrack UPA” as appropriate) to produce a wax / long-chain polymerizable monomer dispersion A1 (emulsion solid content concentration = 30.2 mass%). did.

Preparation of silicone wax dispersion A2 27 parts (540 g) of alkyl-modified silicone wax (melting point 72 ° C.), 1.9 parts of 20% DBS aqueous solution and 71.1 parts of demineralized water were placed in a 3 L stainless steel container and heated to 90 ° C. Then, the mixture was stirred for 10 minutes at a rotation speed of 8000 rpm with a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.).

  Next, this dispersion was heated to 99 ° C., and circulation emulsification was started under a pressure condition of about 45 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). A silicone wax dispersion A2 (emulsion solid content concentration = 27.4% by mass) was prepared by dispersing until the particle diameter reached 240 nm.

-Preparation of polymer primary particle dispersion A1 A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device (inner volume 21 L, inner diameter 250 mm, height 420 mm) 35.6 parts by weight of wax / long-chain polymerizable monomer dispersion A1 (712.12 g) and 259 parts of demineralized water were added and the temperature was raised to 90 ° C. under a nitrogen stream while stirring at 103 rpm. Warm up.

  Thereafter, a mixture of the following monomers and an aqueous emulsifier solution was added over 5 hours from the start of polymerization. The time at which the mixture of the monomers and the aqueous emulsifier solution was started to be dropped was set as the polymerization start, and the following initiator aqueous solution was added over 4.5 hours from 30 minutes after the start of the polymerization. The aqueous agent solution was added over 2 hours, and the mixture was further maintained for 1 hour while maintaining the rotation speed of 103 rpm and the internal temperature of 90 ° C.

[Monomers]
Styrene 76.8 parts (1535.0 g)
23.2 parts butyl acrylate
Acrylic acid 1.5 parts
1.0 part of trichlorobromomethane
Hexanediol diacrylate 0.7 parts [emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part
67.1 parts of demineralized water
[Initiator aqueous solution]
15.5 parts of 8% hydrogen peroxide solution
15.5 parts of 8% L (+)-ascorbic acid aqueous solution
[Additive initiator aqueous solution]
8% L (+)-ascorbic acid aqueous solution 14.2 parts

  After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A1. The volume average particle diameter measured by Microtrac UPA was 280 nm, and the solid content concentration was 21.1% by mass.

-Preparation of polymer primary particle dispersion A2
Into a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device 23. 6 parts by weight (472.3 g), 20% DBS aqueous solution 1.5 parts by weight and demineralized water 324 parts were charged, heated to 90 ° C. under a nitrogen stream, and 8% hydrogen peroxide with stirring at 103 rpm. 3.2 parts of an aqueous solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once.

  5 minutes later, polymerization of the following mixture of monomers and emulsifier aqueous solution was started (from the time when 3.2 parts of 8% hydrogen peroxide aqueous solution and 3.2 parts of 8% L (+)-ascorbic acid aqueous solution were added all at once. After 5 minutes, the following initiator aqueous solution was added over 6 hours from the start of polymerization, and the mixture was further maintained for 1 hour while maintaining the rotation speed at 103 rpm and the internal temperature of 90 ° C.

[Monomers]
92.5 parts of styrene (1850.0 g)
7.5 parts butyl acrylate
Acrylic acid 1.5 parts
0.6 parts of trichlorobromomethane
[Emulsifier aqueous solution]
1.5 parts of 20% DBS aqueous solution
66.2 parts of demineralized water
[Initiator aqueous solution]
18.9 parts of 8% aqueous hydrogen peroxide solution
18.9 parts of 8% L (+)-ascorbic acid aqueous solution

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A2. The volume average particle diameter measured by Microtrac UPA was 290 nm, and the solid content concentration was 19.0% by mass.

-Preparation of colorant dispersion A
Carbon black (Mitsubishi Chemical Co., Ltd.) produced by a furnace method in which a 300 L inner volume container equipped with a stirrer (propeller blade) has an ultraviolet absorbance of 0.02 and a true density of 1.8 g / cm ³ in a toluene extract. Mitsubishi Carbon Black MA100S) 20 parts (40 kg), 20% DBS aqueous solution 1 part, nonionic surfactant (manufactured by Kao Corp., Emulgen 120) 4 parts, ion-exchanged water 75 parts with an electric conductivity of 2 μS / cm In addition, it was predispersed to obtain a pigment premix solution. The conductivity was measured using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation).

The volume cumulative 50% diameter Dv50 of the carbon black in the dispersion after the premix was about 90 μm. The premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. The inner diameter of the stator was φ75 mm, the separator diameter was φ60 mm, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 50 μm (true density of 6.0 g / cm ³ ) were used as a dispersion medium. The effective internal volume of the stator is about 0.5 L, and the media filling volume is 0.35 L, so the media filling rate is 70%.

  The premix slurry is continuously supplied from the supply port at a supply speed of about 50 L / hr by a non-pulsating metering pump, and the rotation speed of the rotor is constant (the peripheral speed of the rotor tip is about 11 m / sec), and continuously from the discharge port. The black colorant dispersion A was obtained by discharging the liquid. The volume average particle diameter measured by Microtrac UPA was 150 nm, and the solid content concentration was 24.2% by mass.

-Production of developing mother particle A Polymer primary particle dispersion A1 95 parts as solids (998.2 g as solids)
Polymer primary particle dispersion A2 5 parts as solid content
Colorant fine particle dispersion A 6 parts as colorant solid content
20% DBS aqueous solution 0.1 parts as solid content
Using each of the above components, a toner was produced by the following procedure.

Polymer primary particle dispersion A1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirring device (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device An aqueous DBS solution was charged and mixed uniformly at an internal temperature of 12 ° C. and 40 rpm for 5 minutes. Subsequently, the stirring rotation speed was increased to 250 rpm at an internal temperature of 12 ° C., and 0.52 part of FeSO ₄ .7H ₂ O as a 5% aqueous solution of ferrous sulfate was added over 5 minutes. Was added uniformly over 5 minutes at an internal temperature of 12 ° C. while maintaining 250 rpm, and a 0.5% aqueous solution of aluminum sulfate was added dropwise under the same conditions (the solid content with respect to the resin solid content was 0.00). 10 parts). Thereafter, the temperature was raised to 53 ° C. over 75 minutes at 250 rpm, and then raised to 56 ° C. over 170 minutes. Here, when the particle size measurement was performed with a precision particle size distribution measuring apparatus (Multisizer III: manufactured by Beckman Coulter, Inc.) (hereinafter, simply referred to as “Multisizer”) with an aperture diameter of 100 μm, a 50% volume diameter was obtained. It was 6.7 μm.

  Thereafter, the polymer primary particle dispersion A2 was added at 250 rpm over 3 minutes and held for 60 minutes, and the rotation speed was reduced to 168 rpm and immediately 20% DBS aqueous solution (6 parts as solid content) was taken over 10 minutes. Then, the temperature was raised to 90 ° C. while maintaining 168 rpm over 30 minutes, and held for 60 minutes.

  Thereafter, the slurry obtained by cooling to 30 ° C. over 20 minutes was extracted, and suction filtration was performed with an aspirator using 5 types C (No5C manufactured by Toyo Roshi Kaisha, Ltd.) filter paper. The cake remaining on the filter paper was transferred to a stainless steel container with an internal volume of 10 L equipped with a stirrer (propeller blade), and 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm was added and stirred uniformly at 50 rpm. Thereafter, stirring was continued for 30 minutes.

  Then, again, suction filtration is performed by an aspirator using 5 types C (Toyo Filter Paper No. 5C) filter paper, and the solid matter remaining on the filter paper is again equipped with a stirrer (propeller blade) and has an electric conductivity of 1 μS / cm. It was transferred to a container with an internal volume of 10 L containing 8 kg of ion-exchanged water, uniformly dispersed by stirring at 50 rpm, and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm. The conductivity was measured using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation).

  The cake obtained here was spread on a stainless steel vat so as to have a height of about 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain development mother particles A.

-Production of developing toner A In a Henschel mixer with an internal volume of 1 L (diameter: 230 mm, height: 240 mm) equipped with a stirrer (Z / A0 blade) and a deflector oriented perpendicularly to the wall surface from the top, 100 parts of developing mother particles A (1000 g) was added, followed by 0.5 part of silica fine particles having a volume average primary particle size of 0.04 μm hydrophobized with silicone oil, and a volume average primary particle size of 0.012 μm hydrophobized with silicone oil. Toner A for development was obtained by adding 2.0 parts of silica fine particles, stirring and mixing at 3000 rpm for 10 minutes, and sieving through 150 mesh. The volume average particle diameter Dv of Toner A measured by Multisizer was 7.05 μm, Dv / Dn was 1.14, and the 50% circularity measured by FPIA2000 was 0.963.

  By using a commercially available printer (ML9300 manufactured by Oki Data Co., Ltd.) in the same manner as in Example 2 except that the developing toner A is used, the same photosensitive drum C as in Example 2 is used, and the cartridge is incorporated as a black cartridge. As a result of the printing durability test, the amount of film reduction was 0.42 μm after printing 10,000 sheets, and 0.75 μm after printing 20,000 sheets, both of which were less than 1 μm and extremely excellent in durability. The evaluation based on the criteria described in Example 2 was ◎.

  As can be seen from the above, the electrophotographic photosensitive member of the present invention containing a polymer composed of repeating units containing the partial structure represented by the formula (1) has a sufficiently small film reduction amount and excellent durability. I understood.

  Since the image forming method of the present invention has high resolution and excellent durability even after repeated use over a long period of time, it is widely used in apparatuses using electrophotographic processes such as copying machines, laser printers, facsimiles, and plate-making machines. It can be used suitably.

1 is a conceptual diagram illustrating an example of an image forming apparatus using an electrophotographic photosensitive member of the present invention. It is a conceptual diagram which shows an example of a roller-shaped contact charging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging apparatus 2a Charging roller 21 Core material of charging roller 22 Roller-shaped contact charging member (supporting member of charging roller)
23 Roller contact charging member (surface member of charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (8)

An electrophotographic photoreceptor for developing an electrostatic latent image formed on a surface with a polymerized toner, wherein the photosensitive layer contains a polymer composed of repeating units including a partial structure represented by formula (1) An electrophotographic photosensitive member characterized by comprising:

  The electrophotographic photosensitive member according to claim 1, wherein the polymer is polycarbonate and / or polyester.   3. The electrophotographic photoreceptor according to claim 1, wherein the polymer toner has a 50% circularity of 0.9 or more.   4. The electrophotographic photosensitive member according to claim 1, wherein the polymerized toner has an SF-1 of 140 or less.   The electrophotographic photosensitive member according to claim 1, wherein the polymerized toner is obtained by an emulsion polymerization aggregation method.   6. The electrophotographic photosensitive member according to claim 1, for charging by a contact charging member.   The electrophotographic photosensitive member according to claim 6, wherein the contact charging member is a roller-shaped contact charging member. An image forming apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 7.

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