JP2011112801A - Electrophotographic photoreceptor, process cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having suppressed image density unevenness after elapse of time of storage. <P>SOLUTION: In this electrophotographic photoreceptor having a conductive substrate, a photosensitive layer provided on the conductive substrate, and a surface protective layer provided on the photosensitive layer, the surface protective layer is constituted by comprising a crosslinked product of at least one compound selected from guanamine compound and melamine compound, and at least one charge transport material having at least one substituent selected from -OH, -OCH<SB>3</SB>, -NH<SB>2</SB>, -SH and -COOH, and includes at least one compound of 0.1-5 mass%, selected from the guanamine compound and the melamine compound, and when the electrophotographic photoreceptor is packaged, a surface oxygen amount by X-ray photoelectron spectroscopic measurement (XPS measurement) in the surface protective layer after unsealing the package is 4-8 atm%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

  In recent years, resins having high mechanical strength have been used in electrophotographic photoreceptors, and the lifetime has been further extended. For example, in Patent Document 1, a photoreceptor using an epoxy resin as a binder resin is used, and in Patent Document 2, a charge transporting material having an epoxy resin and an epoxy group is used. In Patent Documents 3 and 4, a charge transporting material having a phenol resin and a hydroxyl group is used for the protective layer.

  Patent Document 5 discloses an electrophotographic photosensitive member in which a photosensitive layer including an organic photosensitive layer is provided on a conductive substrate, and the outermost surface of the photosensitive layer includes tetrafluoromethane and nitrogen or nitrogen and a rare gas. There has been proposed an electrophotographic photosensitive member characterized in that it is surface-treated with a gas plasma containing it.

JP-A-56-51749 JP-A-8-278645 JP 2002-82469 A JP 2003-186234 A JP 2007-310301 A

  The problem of the present invention is that when the electrophotographic photosensitive member is packaged, the surface oxygen content in the surface protective layer after opening the package is less than the following range compared to the case where the surface oxygen amount is outside the following range. An object of the present invention is to provide an electrophotographic photosensitive member in which uneven image density later is suppressed.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate, a photosensitive layer provided on the conductive substrate,
A surface protective layer provided on the photosensitive layer;
Have
The surface protective layer includes at least one compound selected from a guanamine compound and a melamine compound, and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. And at least one compound selected from the guanamine compound and the melamine compound is contained in an amount of 0.1% by mass or more and 5% by mass or less. ,
In addition, when the electrophotographic photosensitive member is packaged, an electrophotographic photosensitive member having a surface oxygen amount of 4 atm% or more and 8 atm% or less by X-ray photoelectron spectroscopy measurement (XPS measurement) in the surface protective layer after the package is opened.

The invention according to claim 2
The electrophotographic photosensitive member according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
^{F - ((- R 13 -X} ) n1 (R 14) n2 -Y) n3 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, and R ¹³ and R ¹⁴ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, n3 represents an integer of 1 to 4, X represents an oxygen, NH, or sulfur atom, Y represents —OH, —OCH ₃ , _-NH 2, shown -SH, or -COOH.)

The invention according to claim 3
A conductive substrate; a photosensitive layer provided on the conductive substrate; and a surface protective layer provided on the photosensitive layer, wherein the surface protective layer is selected from a guanamine compound and a melamine compound. A cross-linked product of at least one compound and at least one charge transporting material having at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. And an electrophotographic photoreceptor containing at least one compound selected from the guanamine compound and the melamine compound in an amount of 0.1% by mass to 5% by mass,
When the process cartridge is packaged, the amount of surface oxygen by X-ray photoelectron spectroscopy (XPS measurement) in the surface protective layer after opening the package is 4 atm% or more and 8 atm% or less,
A process cartridge that is detachable from the image forming apparatus.

The invention according to claim 4
The process cartridge according to claim 3, wherein the charge transporting material is a compound represented by the following general formula (I).
^{F - ((- R 13 -X} ) n1 (R 14) n2 -Y) n3 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, and R ¹³ and R ¹⁴ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, n3 represents an integer of 1 to 4, X represents an oxygen, NH, or sulfur atom, Y represents —OH, —OCH ₃ , _-NH 2, shown -SH, or -COOH.)

The invention according to claim 5
The electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the electrophotographic photoreceptor;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for containing a developer containing toner and developing the electrostatic latent image formed on the electrophotographic photosensitive member into a toner image by the developer;
Transfer means for transferring the toner image to a transfer object;
An image forming apparatus comprising:

According to the first and second aspects of the invention, when the electrophotographic photosensitive member is packaged, the surface oxygen amount by X-ray photoelectron spectroscopy (XPS measurement) in the surface protective layer after the package is opened is outside the above range. Compared to the case, an electrophotographic photosensitive member in which uneven image density after storage has been suppressed is provided.
According to the third and fourth aspects of the present invention, when the process cartridge is packaged, the amount of surface oxygen measured by X-ray photoelectron spectroscopy (XPS measurement) in the electrophotographic photosensitive surface protective layer after opening the package is within the above range. A process cartridge is provided in which unevenness in image density after storage has been suppressed compared to the case outside.
According to the fifth aspect of the present invention, when the electrophotographic photosensitive member is packaged, the surface oxygen content in the surface protective layer after the package is unsealed by X-ray photoelectron spectroscopy (XPS measurement) is outside the above range. An image forming apparatus in which image density unevenness is suppressed as compared with the case where a photoconductor is applied is provided.

1 is a schematic partial cross-sectional view showing an electrophotographic photosensitive member according to the present embodiment. It is a general | schematic fragmentary sectional view which shows the electrophotographic photoreceptor which concerns on other this embodiment. It is a general | schematic fragmentary sectional view which shows the electrophotographic photoreceptor which concerns on other this embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on other this embodiment.

  Embodiments that are examples of the present invention will be described below.

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor according to the exemplary embodiment includes a conductive substrate, a photosensitive layer provided on the conductive substrate, and a surface protective layer provided on the photosensitive layer. The surface protective layer includes at least one compound selected from a guanamine compound and a melamine compound, and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. And at least one compound selected from the guanamine compounds and melamine compounds is contained in an amount of 0.1% by mass or more and 5% by mass or less. .
When the electrophotographic photosensitive member according to the present embodiment is packaged, the surface oxygen amount in the surface protective layer after opening the package is 4 atm% or more and 8 atm% or less by X-ray photoelectron spectroscopy measurement (XPS measurement). .

  Here, in the electrophotographic photoreceptor according to the exemplary embodiment, the surface protective layer is configured as described above, so that a cross-linked site (cross-linking site) is formed by a guanamine compound or a melamine compound and a charge transporting material having a specific functional group. ) Is polyfunctionalized, and as a result, it is considered that a film is formed which is highly cross-linked, increases in mechanical strength, and suppresses fluctuations in electrical properties depending on the environment. And this highly cross-linked state by reducing the guanamine compound and melamine compound below the specified amount, and increasing the amount of the charge transport material above the specified amount and the conventional electrophotographic photoreceptor. While maintaining the above, it is considered that the increase in the residual potential is suppressed with respect to the electrical characteristics, the ghost resistance is improved with respect to the image quality characteristics, and the deterioration of the electrical characteristics and the image quality characteristics is suppressed. In addition, by combining a guanamine compound or melamine compound with a charge transporting material having a specific functional group, the surface of the charge transporting material can be increased to a predetermined amount or more compared to a conventional electrophotographic photoreceptor. It is considered that wrinkles and unevenness are suppressed even when the protective layer is thickened.

  On the other hand, when an electrophotographic photosensitive member having such a surface protective layer is produced and then exposed to the atmosphere and stored, the phenomenon that the potential of the light irradiation part becomes lower than immediately after the production of the electrophotographic photosensitive member is observed. May occur. This is because the outermost surface layer of the electrophotographic photosensitive member is reduced to less than the above specified amount of guanamine compounds and melamine compounds, and the amount of the charge transporting material is more than the above specified amount, compared with the conventional electrophotographic photosensitive member. This is thought to be due to the fact that

Therefore, in the electrophotographic photosensitive member according to the present embodiment, when packaged, the surface oxygen amount by XPS measurement in the surface protective layer after opening the package is set in the above range, so that the electrophotographic photosensitive member is immediately manufactured ( For example, it is considered that the potential drop of the light irradiation portion is suppressed as compared with (within 24 hours after production), and as a result, the image density unevenness after storage is suppressed.
Similarly, a process cartridge that includes the electrophotographic photosensitive member according to the present embodiment and is detachable from the image forming apparatus also has a surface oxygen amount measured by XPS measurement in the surface protective layer after the package is opened. By setting it within the above range, it is considered that the decrease in the potential of the light-irradiated part is suppressed as compared with immediately after the production of the electrophotographic photosensitive member (for example, within 24 hours after the production). Unevenness is suppressed.

Here, the surface oxygen amount by XPS measurement in the surface protective layer after opening the package is performed as follows. The packaged electrophotographic photosensitive member (or a process cartridge including the same) is opened, and XPS measurement is performed on the surface of the surface protective layer of the electrophotographic photosensitive member within 24 hours after opening.
The XPS measurement itself is performed by using JPS-9010MX manufactured by JEOL, cutting out about 10 mm × 10 mm for the measurement sample from the electrophotographic photosensitive member.

In the electrophotographic photosensitive member according to the present embodiment, “the surface oxygen amount by XPS measurement in the surface protective layer after opening the package is in the above range” includes, for example, an electrophotographic photosensitive member (or a process cartridge including the same). For example, a so-called laminate package may be used in which packaging is performed with a packaging film while degassing, for example, before 24 hours have elapsed. Thereby, it becomes easy to suppress the fluctuation | variation of the amount of surface oxygen in the surface protective layer of an electrophotographic photoreceptor with storage progress.
Here, as a packaging film for packaging, for example, a multilayer film such as a laminate film in which a base material (for example, polyethylene terephthalate (PET)), a metal foil (for example, Al foil), and a heat-resistant resin (for example, heat-resistant CPP) are laminated. Is mentioned.
Further, the packaging is performed while deaeration. As the deaeration state, it is preferable that the degree of ultimate vacuum is 320 torr or less.

Hereinafter, it will be described in detail with reference to the drawings.
1 to 3 schematically show a cross section of a part of an electrophotographic photoreceptor 10 according to the present embodiment.
The electrophotographic photosensitive member 10 shown in FIG. 1 is provided with an undercoat layer 1 on a conductive support 4, a charge generation layer 2 and a charge transport layer 3 are provided on the undercoat layer as photosensitive layers, and further, A surface protective layer 5 serving as a surface layer is provided.
The electrophotographic photoreceptor 10 shown in FIG. 2 includes a photosensitive layer having functions separated into a charge generation layer 2 and a charge transport layer 3 as in the electrophotographic photoreceptor 10 shown in FIG. A charge transport layer 3, a charge generation layer 2, and a surface protective layer 5 are sequentially provided on 1.
An electrophotographic photoreceptor 10 shown in FIG. 3 contains a charge generation material and a charge transport material in the same layer, that is, a single-layer type photosensitive layer 6 (charge generation / charge transport layer). A surface protective layer 5 is provided.
Hereinafter, each element will be described based on the electrophotographic photoreceptor 10 shown in the drawing as a representative example. Note that the reference numerals are omitted.

-Conductive substrate-
Any conductive substrate may be used as long as it is conventionally used. For example, thin films (eg, metals such as aluminum, nickel, chromium, stainless steel, and films of aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, indium tin oxide (ITO), etc.) And a plastic film coated or impregnated with a conductivity-imparting agent, a plastic film coated or impregnated with a conductivity-imparting agent, and the like. The shape of the substrate is not limited to a cylindrical shape, and may be a sheet shape or a plate shape.

  When a metal pipe is used as the conductive substrate, the surface may be left as it is, and treatments such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, and wet honing have been performed in advance. Also good.

-Undercoat layer-
The undercoat layer is provided as necessary for the purpose of preventing light reflection on the surface of the conductive substrate and preventing inflow of unnecessary carriers from the conductive substrate to the photosensitive layer.

The undercoat layer includes, for example, a binder resin and, if necessary, other additives.
As the binder resin contained in the undercoat layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, Known polymer resin compounds such as polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, and charge transporting group Examples thereof include charge transporting resins having a conductive resin such as polyaniline. Among these, resins that are insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used.

  The undercoat layer may contain a metal compound such as a silicon compound, an organic zirconium compound, an organic titanium compound, or an organic aluminum compound.

  The ratio between the metal compound and the binder resin is not particularly limited, and is arbitrarily set within a range in which desired electrophotographic photoreceptor characteristics can be obtained.

  In the undercoat layer, resin particles may be added to the undercoat layer in order to adjust the surface roughness. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate (PMMA) resin particles. The surface may be polished after forming the undercoat layer for adjusting the surface roughness. As a polishing method, buffing, sandblasting, wet honing, grinding, or the like is used.

Here, the constitution of the undercoat layer includes a constitution containing at least a binder resin and conductive particles. Note that the conductive particles preferably have conductivity with a volume resistivity of less than 10 ⁷ Ω · cm, for example.

Examples of the conductive particles include metal particles (particles such as aluminum, copper, nickel, and silver), conductive metal oxide particles (particles such as antimony oxide, indium oxide, tin oxide, and zinc oxide), and conductive substance particles. (Carbon fiber, carbon black, particles of graphite powder) and the like. Among these, conductive metal oxide particles are preferable. You may mix and use 2 or more types of electroconductive particle.
In addition, the conductive particles may be subjected to a surface treatment with a hydrophobizing agent (for example, a coupling agent) or the like to adjust the resistance.
For example, the content of the conductive particles is preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

In forming the undercoat layer, an undercoat layer forming coating solution in which the above components are added to a solvent is used.
In addition, as a method of dispersing particles in the coating solution for forming the undercoat layer, a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirring, an ultrasonic dispersing machine, a roll mill, a high-pressure homogenizer, etc. Medialess dispersers are used. Here, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state. .

  Examples of the method for applying the coating solution for forming the undercoat layer onto the conductive substrate include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. It is done.

  The thickness of the undercoat layer is preferably 15 μm or more, and more preferably 20 μm or more and 50 μm or less.

  Here, although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer. As the binder resin used for the intermediate layer, acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl In addition to polymer resins such as acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atom, etc. An organometallic compound containing These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, an organometallic compound containing zirconium or silicon is preferable in that it has a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

In forming the intermediate layer, a coating solution for forming an intermediate layer in which the above components are added to a solvent is used.
As the coating method for forming the intermediate layer, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method are used.

  In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer. However, if the film thickness is too large, the electrical barrier becomes too strong and the potential increases due to desensitization or repetition. May cause. Therefore, when forming the intermediate layer, it is preferable to set the film thickness within the range of 0.1 μm to 3 μm. In this case, the intermediate layer may be used as the undercoat layer.

-Charge generation layer-
The charge generation layer includes, for example, a charge generation material and a binder resin. Examples of such a charge generating material include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine. A chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, a Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 7 Metal-free phthalocyanine crystals having strong diffraction peaks at .7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 °, and 28.8 °, Bragg angle (2θ ± 0) with respect to CuKα characteristic X-rays .2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 ° Hydroxygallium phthalocyanine crystals having strong diffraction peaks at 25.1 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 9.6 °, 24.1 ° and 27.2 A titanyl phthalocyanine crystal having a strong diffraction peak at 0 ° can be mentioned. In addition, examples of the charge generation material include quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments, and the like. These charge generation materials may be used alone or in combination of two or more.

Examples of the binder resin constituting the charge generation layer include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene. Copolymer resin, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride Examples thereof include resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, poly-N-vinylcarbazole resins. These binder resins may be used alone or in combination of two or more.
The mixing ratio of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10, for example.

  When forming the charge generation layer, a coating solution for forming a charge generation layer in which the above components are added to a solvent is used.

  As a method for dispersing particles (for example, electrification generating material) in the coating solution for forming the charge generation layer, a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, or a roll mill. Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

  Examples of the method for applying the charge generation layer forming coating liquid on the undercoat layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. It is done.

  The thickness of the charge generation layer is desirably set in the range of 0.01 μm to 5 μm, more desirably 0.05 μm to 2.0 μm.

-Charge transport layer-
The charge transport layer includes a charge transport material and, if necessary, a binder resin. When the charge transport layer corresponds to the outermost surface layer, as described above, the charge transport layer includes the fluororesin particles having the specific surface area.

  Examples of the charge transport material include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [ Pyrazoline derivatives such as pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, N, N′-bis (3,4-dimethylphenyl) biphenyl- Aromatic tertiary amino compounds such as 4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline, N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine Aromatic tertiary diamino compounds such as 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphenyl) -1,2,4 1,2,4-triazine derivatives such as triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2,3- Benzofuran derivatives such as di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly -Hole transport materials such as -N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and broanthraquinone, tetraanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7 -Fluorenone such as tetranitro-9-fluorenone Examples thereof include an electron transport material such as a compound, a xanthone compound, and a thiophene compound, and a polymer having a group consisting of the above-described compounds in a main chain or a side chain. These charge transport materials may be used alone or in combination of two or more.

Examples of the binder resin constituting the charge transport layer include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene. Copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-anhydrous maleic acid Insulating resins such as acid resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, chlorinated rubber, and polyvinylcarbazole and polyvinylanthra Emissions, organic photoconductive polymers such as polyvinyl pyrene, and the like. These binder resins may be used alone or in combination of two or more.
The mixing ratio between the charge transport material and the binder resin is preferably 10: 1 to 1: 5, for example.

  The charge transport layer is formed using a charge transport layer forming coating solution in which the above components are added to a solvent.

  As a method for dispersing particles (for example, fluororesin particles) in the coating liquid for forming the charge transport layer, a media dispersing machine such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirring, an ultrasonic dispersing machine, a roll mill, etc. Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

Examples of methods for applying the charge transport layer forming coating solution onto the charge generation layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. The usual method is used.
The film thickness of the charge transport layer is desirably set in the range of 5 μm to 50 μm, more desirably 10 μm to 40 μm.

-Surface protective layer-
The surface protective layer has charge transport having at least one selected from a guanamine compound and a melamine compound and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. It is comprised with the cured film of at least 1 sort (s) of a property material. That is, a charge transporting material having at least one selected from a guanamine compound and a melamine compound and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH (hereinafter referred to as “a”). , “Sometimes referred to as“ specific charge transporting material ”)), and a crosslinked product using a coating solution.

First, the guanamine compound will be described.
The guanamine compound is a compound having a guanamine skeleton (structure), and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.
The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). In addition, the compound shown by general formula (A) may be used individually by 1 type, but may use 2 or more types together. In particular, when the compound represented by the general formula (A) is used as a mixture of two or more kinds, or used as a multimer (oligomer) having the same as a structural unit, the solubility in a solvent is improved.

In general formula (A), R ₁ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R ₂ to R ₅ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ₆ . R ₆ represents a linear or branched alkyl group having 1 to 10 carbon atoms.
In the general formula (A), the alkyl group representing R ₁ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.
In general formula (A), the phenyl group represented by R ₁ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.
In general formula (A), the alicyclic hydrocarbon group representing R ₁ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.
In the general formula (A), in “—CH ₂ —O—R ₆ ” representing R ₂ to R ₅ , the alkyl group representing R ₆ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 or less and 8 or more, and more preferably 1 or more and 6 or less. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.

As the compound represented by the general formula (A), it is particularly desirable that R ₁ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ₂ to R ₅ are each independently —CH ₂ —O. is a compound that shows a -R _6. R ₆ is preferably selected from a methyl group and an n-butyl group.
The compound represented by the general formula (A) is synthesized by, for example, a known method using guanamine and formaldehyde (for example, edited by The Chemical Society of Japan, Experimental Chemistry 4th Edition, Volume 28, page 430).
Hereinafter, exemplary compounds: (A) -1 to (A) -42 are shown as specific examples of the compound represented by the general formula (A), but this embodiment is not limited thereto. The following specific examples are monomers, but multimers (oligomers) having these monomers as structural units may also be used. In the following exemplary compounds, “Me” represents a methyl group, “Bu” represents a butyl group, and “Ph” represents a phenyl group.

Moreover, as a commercial item of the compound shown by general formula (A), for example, super becamine (R) L-148-55, super becamine (R) 13-535, super becamine (R) L-145 -60, Super Becamine (R) TD-126 (manufactured by Dainippon Ink and Co., Ltd.), Nicarak BL-60, Nicarac BX-4000 (manufactured by Nippon Carbide) and the like.
In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, the melamine compound will be described.
The melamine compound is a melamine skeleton (structure), and is particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit in the same manner as the general formula (A), and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more). 100 or less). In addition, the compound shown by General formula (B) or its multimer may be used individually by 1 type, and may use 2 or more types together. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer. In particular, when the compound represented by the general formula (B) is used as a mixture of two or more kinds or used as a multimer (oligomer) having the same as a structural unit, the solubility in a solvent is improved.

In General Formula (B), R ⁶ to R ¹¹ each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹² , —O—R ¹² , and R ¹² has 1 or more carbon atoms. The alkyl group which may branch 5 or less is shown. Examples of the alkyl group include a methyl group, an ethyl group, and a butyl group.
The compound represented by the general formula (B) is synthesized by a known method using, for example, melamine and formaldehyde (for example, synthesized in the same manner as the melamine resin in Experimental Chemistry Course 4th Edition, Volume 28, page 430). )
Hereinafter, exemplary compounds: (B) -1 to exemplary compound: (B) -8 are shown as specific examples of the compound represented by the general formula (B), but this embodiment is not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (Nippon Yushi Co., Ltd.), Super Becamine (R) TD-139-60 (Dainippon Ink Co., Ltd.), Uban 2020 (Mitsui Chemicals Co., Ltd.), Smitex Resin M-3 (Sumitomo Chemical Co., Ltd.), Nicarak MW-30 (manufactured by Nippon Carbide), and the like.
In addition, the compound represented by the general formula (B) (including multimers) can be used in an appropriate solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

Next, a specific charge transport material will be described. As the specific charge transporting material, for example, a material having at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH is preferably exemplified. In particular, the specific charge transporting material includes a charge transporting material having at least two (or three) substituents selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. Preferably mentioned. As described above, the reactive functional group (substituent) increases in a specific charge transporting material, so that the crosslink density is increased and a cross-linked film having higher strength is obtained. In particular, a foreign matter removing member such as a blade member is used. The rotational torque of the electrophotographic photosensitive member at the time is reduced, and the wear of the foreign matter removing member and the wear of the electrophotographic photosensitive member are suppressed. Although the details of this reason are unclear, since a cured film having a high crosslinking density can be obtained by increasing the number of reactive functional groups, molecular motion on the extreme surface of the electrophotographic photoreceptor is suppressed, and the blade member It is presumed that the interaction with the surface molecules is weakened.

The specific charge transporting material is preferably a compound represented by the following general formula (I) from the viewpoint of suppressing wear of the foreign matter removing member and suppressing wear of the electrophotographic photosensitive member.
^{F - ((- R 13 -X} ) n1 (R 14) n2 -Y) n3 (I)
In general formula (I), F is an organic group derived from a compound having a hole transporting ability, R ¹³ and R ¹⁴ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, and n3 represents an integer of 1 or more and 4 or less. X represents an oxygen, NH, or sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.
In general formula (I), an arylamine derivative is preferably used as the compound having a hole transporting ability in an organic group derived from a compound having a hole transporting ability represented by F. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.
The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II). The compound represented by the general formula (II) is particularly excellent in charge mobility, stability against oxidation and the like.

In general formula (II), Ar ¹ to Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted group. D represents — (— R ¹³ —X) _n1 (R ¹⁴ ) _n2 —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 or less. R ¹³ and R ¹⁴ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, n2 represents 0 or 1, and X represents oxygen. , NH, or a sulfur atom, and Y represents —OH, —OCH ₃ , —NH ₂ , —SH, or —COOH.
In the general formula (II), “— (— R ¹³ —X) _n1 (R ¹⁴ ) _n2 —Y” representing D is the same as in the general formula (I), and R ¹³ and R ¹⁴ are each independently carbon. A linear or branched alkylene group having a number of 1 or more and 5 or less. N1 is preferably 1. N2 is preferably 1. X is preferably oxygen. Y is preferably a hydroxyl group.
The total number of D in the general formula (II) corresponds to n3 in the general formula (I), preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less.
Further, in the general formula (I) or general formula (II), when the total number of D is 2 or more and 4 or less, preferably 3 or more and 4 or less in one molecule, the crosslinking density is increased and a crosslinked film having higher strength is obtained. In particular, the rotational torque of the electrophotographic photosensitive member when using a blade member for removing foreign matter is reduced, and the wear of the blade member and the wear of the electrophotographic photosensitive member are suppressed. Although details of this are unknown, as described above, by increasing the number of reactive functional groups, a cured film having a high crosslinking density is obtained, and molecular motion on the extreme surface of the electrophotographic photosensitive member is suppressed, so that the blade member This is presumed to be due to weakening of interaction with surface molecules.

In general formula (II), Ar ₁ to Ar ₄ are preferably any one of the following formulas (1) to (7). The following formulas (1) to (7) are shown together with “— (D) _C ” which can be connected to each Ar ₁ to Ar ₄ .

In formulas (1) to (7), R ¹⁵ is phenyl substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents a group selected from the group consisting of a group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ¹⁶ to R ¹⁸ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a carbon number One selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom Ar represents a substituted or unsubstituted arylene group, D and c are the same as “D” and “c” in formula (II), s represents 0 or 1, and t is 1 or more, respectively. 3 or less A representative.
Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

In formulas (8) to (9), R ¹⁹ and R ²⁰ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. This represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, and t represents an integer of 1 to 3.
Further, as Z ′ in the formula (7), one represented by any of the following formulas (10) to (17) is desirable.

In formulas (10) to (17), R ²¹ and R ²² are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. This represents one selected from the group consisting of a substituted phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent 1 Represents an integer of 10 or less, and t represents an integer of 1 or more and 3 or less, respectively.
W in the above formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In the general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the explanation of Ar ¹ to Ar ⁴ when k is 0, and when k is 1, These are arylene groups obtained by removing a hydrogen atom from the above aryl groups (1) to (7).
Specific examples of the compound represented by the general formula (I) include the following compounds. In addition, the compound shown by the said general formula (I) is not limited at all by these.

Here, at least one content selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)) (solid content concentration in the coating solution) is: It is 0.1 mass% or more and 5 mass% or less, Desirably 1 mass% or more and 3 mass% or less. If the solid content concentration is less than 0.1% by mass, it is difficult to obtain a dense film, so that sufficient strength is difficult to obtain. If it exceeds 5% by mass, electrical properties and ghost resistance (density unevenness due to image history) are exhibited. May get worse.
On the other hand, the content (solid content concentration in the coating solution) of at least one specific charge transporting material is 90% by mass or more, and desirably 94% by mass or more. If this solid content concentration is less than 90% by mass, the electrical characteristics may be deteriorated. The upper limit of the solid content concentration is at least one selected from a guanamine compound (a compound represented by the general formula (A)) and a melamine compound (a compound represented by the general formula (B)), and other additives. Is not limited as long as it functions effectively.

Hereinafter, the surface protective layer will be described in more detail.
The surface protective layer includes at least one selected from a guanamine compound (compound represented by the general formula (A)) and a melamine compound (compound represented by the general formula (B)) and a specific charge transporting material (general formula). A phenol resin, urea resin, alkyd resin, or the like may be mixed and used together with the cross-linked product with the compound (I). In addition, in order to improve the strength, a compound having more functional groups in one molecule such as spiroacetal guanamine resin (for example, “CTU-guanamine”, manufactured by Ajinomoto Fine Techno Co., Ltd.) is used as the material in the cross-linked product. Copolymerization is also effective.

In addition, the surface protective layer is mixed with another thermosetting resin such as a phenol resin for the purpose of effectively suppressing oxidation by the discharge generated gas by adding so that the discharge generated gas is not excessively adsorbed. It may be used.
Further, it is desirable to add a surfactant to the surface protective layer, and the surfactant to be used is particularly a surfactant containing at least one kind of structure among a fluorine atom, an alkylene oxide structure and a silicone structure. Although there is no limitation, those having a plurality of the above structures have high affinity and compatibility with the charge transporting organic compound, and the film forming property of the coating liquid for the surface protective layer is improved, and wrinkles and unevenness of the surface protective layer are suppressed. Therefore, it is preferable.

  Further, the surface protective layer may be used in combination with a coupling agent or a fluorine compound for the purpose of adjusting the film formability, flexibility, lubricity, and adhesion. As this compound, various silane coupling agents and commercially available silicone hard coat agents are used.

Further, a resin that dissolves in alcohol may be added for the purpose of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like of the surface protective layer.
Here, the alcohol-soluble resin means a resin that dissolves 1% by mass or more in an alcohol having 5 or less carbon atoms. Examples of the resin soluble in the alcohol solvent include a polyvinyl acetal resin and a polyvinyl phenol resin.

  It is desirable to add an antioxidant to the surface protective layer for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated in the charging device. When the mechanical strength of the surface of the photoconductor is increased and the photoconductor has a long life, the photoconductor is in contact with the oxidizing gas for a long time, and therefore, stronger oxidation resistance is required than before. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, and more preferably 10% by mass or less.

Furthermore, various particles may be added to the surface protective layer for the purpose of lowering the residual potential or improving the strength. An example of the particles is silicon-containing particles. The silicon-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles.
For the same purpose, an oil such as silicone oil may be added.
Moreover, you may add a metal, a metal oxide, carbon black, etc. to a surface protective layer.

  The surface protective layer is preferably a cured film obtained by curing at least one selected from a guanamine compound and a melamine compound and at least one specific charge transporting material using an acid catalyst. Acid catalysts include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid, aromatics such as benzoic acid, phthalic acid, terephthalic acid, and trimellitic acid Aliphatic and aromatic sulfonic acids such as carboxylic acid, methanesulfonic acid, dodecylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, and naphthalenesulfonic acid are used, but it is desirable to use a sulfur-containing material.

  Here, the compounding amount of the catalyst is at least one amount selected from the guanamine compound (the compound represented by the general formula (A)) and the melamine compound (the compound represented by the general formula (B)) (in the coating solution). The solid content concentration is preferably in the range of 0.1% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass. When the amount is less than the above range, the catalytic activity may be too low, and when it exceeds the above range, the light resistance may be deteriorated. The light resistance refers to a phenomenon in which the irradiated portion causes a decrease in density when the photosensitive layer is exposed to light from the outside such as room light. The cause is not clear, but it is presumed that this is because a phenomenon similar to the optical memory effect occurs as disclosed in JP-A-5-099737.

  The surface protective layer having the above structure is formed using a coating liquid for forming a surface protective layer in which the above components are mixed. The coating solution for forming the surface protective layer may be prepared without a solvent, or may be performed using a solvent as necessary. Such solvents are used singly or in combination of two or more, and preferably have a boiling point of 100 ° C. or lower. As the solvent, it is particularly preferable to use a solvent having at least one hydroxyl group (for example, alcohol).

In addition, when the coating liquid is obtained by reacting the above components, it may be simply mixed and dissolved, but it is room temperature (for example, 25 ° C.) to 100 ° C., preferably 30 ° C. to 80 ° C. for 10 minutes to 100 Heating may be performed for a period of time or less, preferably 1 hour or more and 50 hours or less. It is also desirable to irradiate ultrasonic waves at this time. Thereby, it is likely that a partial reaction proceeds, and it is easy to obtain a film with few coating film defects and little variation in thickness.
Then, a coating solution for forming the surface protective layer is applied by a known method such as a blade coating method, a Mayer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, etc. Accordingly, for example, the surface protective layer can be obtained by heating and curing at a temperature of 100 ° C. or higher and 170 ° C. or lower.

The function-separated type electrophotographic photosensitive member has been described above as an example. However, for example, in the case of forming the single-layer type photosensitive layer (charge generation / charge transport layer) shown in FIG. % Or more and about 85 mass% or less are desirable, and more desirably 20 mass% or more and 50 mass% or less. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less.
The method for forming the single-layer type photosensitive layer is the same as the method for forming the charge generation layer and the charge transport layer. The thickness of the single-layer photosensitive layer is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

(Image forming device and process cartridge)
FIG. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment.
As shown in FIG. 4, the image forming apparatus 101 according to the present embodiment includes, for example, an electrophotographic photosensitive member 10 that rotates clockwise as indicated by an arrow A, and an electronic A charging device 20 (an example of a charging unit) that is provided relative to the photographic photosensitive member 10 and charges the surface of the electrophotographic photosensitive member 10, and the surface of the electrophotographic photosensitive member 10 charged by the charging device 20 is exposed to light. An exposure device 30 (an example of an electrostatic latent image forming unit) that forms an electrostatic latent image, and a toner contained in a developer is attached to the electrostatic latent image formed by the exposure device 30 to form an electrophotographic photosensitive member 10. The developing device 40 (an example of a developing unit) that forms a toner image on the surface and the recording paper P (transfer medium) are charged to a polarity different from the charging polarity of the toner, and the recording paper P is placed on the electrophotographic photoreceptor 10. Transfer device 50 for transferring a toner image , And a cleaning device 70 for cleaning the surface of the electrophotographic photosensitive member 10 (an example of a toner removing means). A fixing device 60 is provided for fixing the toner image while conveying the recording paper P on which the toner image is formed.

  Details of main components in the image forming apparatus 101 according to the present embodiment will be described below.

-Charging device-
Examples of the charging device 20 include a contact charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like. Further, examples of the charging device 20 include a non-contact type roller charger and a known charger such as a scorotron charger using a corona discharge or a corotron charger. As the charging device 20, a contact charger is preferable.

-Exposure device-
Examples of the exposure apparatus 30 include optical system devices that expose the surface of the electrophotographic photoreceptor 10 with light such as semiconductor laser light, LED light, and liquid crystal shutter light imagewise. The wavelength of the light source is preferably within the spectral sensitivity region of the electrophotographic photoreceptor 10. As the wavelength of the semiconductor laser, for example, near infrared having an oscillation wavelength around 780 nm is preferable. However, the present invention is not limited to this wavelength, and a laser having an oscillation wavelength of 600 nm or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. Further, as the exposure apparatus 30, for example, a surface emitting laser light source of a multi-beam output type is also effective for color image formation.

-Developer-
An example of the developing device 40 is a configuration in which a developing roll 41 disposed in the developing region facing the electrophotographic photosensitive member 10 is provided in a container that stores a two-component developer composed of toner and a carrier. The developing device 40 is not particularly limited as long as it is a device that develops with a two-component developer, and a known configuration is employed.

Here, the developer used in the developing device 40 will be described.
The developer may be a one-component developer made of toner, or a two-component developer containing toner and carrier.

  The toner includes, for example, toner particles containing a binder resin, a colorant, and, if necessary, other additives such as a release agent, and external additives as necessary.

The toner particles have an average shape factor (shape factor = (ML ² / A) × (π / 4) × 100), and ML represents the maximum length of the particles, where A represents the maximum length of the particles (Representing the projected area) is preferably from 100 to 150, more preferably from 105 to 145, and even more preferably from 110 to 140. Further, the toner preferably has a volume average particle diameter of 3 μm or more and 12 μm or less, more preferably 3.5 μm or more and 10 μm or less, and further preferably 4 μm or more and 9 μm or less.

  The toner particles are not particularly limited by the production method, and for example, a kneading and pulverizing method in which a binder resin, a colorant and a release agent, and a charge control agent and the like are added and kneaded, pulverized, and classified as necessary; A method of changing the shape of the particles obtained by the kneading and pulverization method by mechanical impact force or thermal energy; the polymerization monomer of the binder resin is emulsion-polymerized, the formed dispersion, the colorant and the release agent Emulsion polymerization aggregation method to obtain a toner particle by mixing a mold agent and, if necessary, a dispersion of a charge control agent, and agglomerating and heat-fusing; a polymerizable monomer for obtaining a binder resin, and coloring Suspension polymerization method in which a solution of an agent, a release agent and, if necessary, a charge control agent is suspended in an aqueous solvent for polymerization; a binder resin, a colorant and a release agent, and if necessary, a charge control agent Toner particles produced by a solution suspension method in which a solution such as a liquid is suspended in an aqueous solvent and granulated There will be used.

  Further, a known method such as a production method in which the toner particles obtained by the above method are used as a core, and agglomerated particles are further adhered and heated and fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner is produced by mixing the toner particles and the external additive with a Henschel mixer or a V blender. Further, when the toner particles are produced by a wet method, they may be externally added by a wet method.

  When the toner is used as a two-component developer, the mixing ratio with the carrier is set at a known ratio. In addition, there is no restriction | limiting in particular as a carrier, For example, what carried out resin coating to the surface of a magnetic particle as a carrier is mentioned suitably.

-Transfer device-
As the transfer device 50, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade or the like, or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

(Cleaning device)
The cleaning device 70 includes, for example, a casing 71, a cleaning blade 72, and a cleaning brush 73 disposed on the downstream side of the cleaning blade 72 in the rotation direction of the electrophotographic photosensitive member 10. Further, for example, a solid lubricant 74 is disposed in contact with the cleaning brush 73.

  Hereinafter, the operation of the image forming apparatus 101 according to the present embodiment will be described. First, the electrophotographic photoreceptor 10 rotates along the direction indicated by the arrow a, and at the same time is negatively charged by the charging device 20.

  The electrophotographic photoreceptor 10 whose surface is negatively charged by the charging device 20 is exposed by the exposure device 30, and a latent image is formed on the surface.

  When the portion where the latent image is formed on the electrophotographic photosensitive member 10 approaches the developing device 40, toner is attached to the latent image by the developing device 40 (developing roll 41), and a toner image is formed.

  When the electrophotographic photosensitive member 10 on which the toner image is formed is further rotated in the direction of arrow a, the toner image is transferred onto the recording paper P by the transfer device 50. As a result, a toner image is formed on the recording paper P.

  The toner image is fixed on the recording paper P on which the image is formed by the fixing device 60.

For example, as illustrated in FIG. 5, the image forming apparatus 101 according to the present embodiment includes an electrophotographic photosensitive member 10, a charging device 20, an exposure device 30, a developing device 40, and a cleaning device 70 in a housing 11. May be provided with a process cartridge 101 </ b> A in which are integrally stored. The process cartridge 101A integrally contains a plurality of members and is attached to and detached from the image forming apparatus 101.
The configuration of the process cartridge 101A is not limited to this. For example, the process cartridge 101A only needs to include at least the electrophotographic photosensitive member 10, and for example, the charging device 20, the exposure device 30, the developing device 40, the transfer device 50, and the cleaning. At least one selected from the apparatus 70 may be provided.

  In addition, the image forming apparatus 101 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 10 and downstream of the transfer device 50 in the rotation direction of the electrophotographic photosensitive member 10. A first neutralization device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member from 70 so that the polarity of the remaining toner is aligned and easy to remove with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 10 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 20. .

  The image forming apparatus 101 according to the present embodiment is not limited to the above-described configuration, and a known configuration, for example, a toner image formed on the electrophotographic photosensitive member 10 is transferred to the intermediate transfer member and then transferred to the recording paper P. An intermediate transfer type image forming apparatus or a tandem type image forming apparatus may be used.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

Example 1
-Production of electrophotographic photoreceptor-
Zinc oxide: (average particle size 70 nm: manufactured by Teica Co., Ltd .: specific surface area value 15 m ² / g) 100 parts by mass is stirred and mixed with 500 parts by mass of toluene, and silane coupling agent (KBM603: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.5 parts by mass. Part was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours to obtain a silane coupling agent surface-treated zinc oxide pigment.
Next, 100 parts by mass of the surface-treated zinc oxide was mixed with 500 parts by mass of tetrahydrofuran, and a solution in which 1 part by mass of alizarin was dissolved in 50 parts by mass of tetrahydrofuran was added, followed by stirring at 50 ° C. for 5 hours. did. Thereafter, zinc oxide to which alizarin was imparted by filtration under reduced pressure was filtered off, and further dried at 60 ° C. under reduced pressure to obtain an alizarin-given zinc oxide pigment.
Next, 60 parts by mass of this alizarin-added zinc oxide pigment and a curing agent (blocked isocyanate Sumidur 3175: manufactured by Sumitomo Bayern Urethane Co., Ltd.): 15 parts by mass and a butyral resin “ESREC BM-1 (manufactured by Sekisui Chemical Co., Ltd.)”: 15 38 parts by mass of a solution obtained by dissolving part by mass in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone were mixed, and dispersion was performed for 2 hours with a sand mill using 1 mmφ glass beads.
As a catalyst, 0.005 part by mass of dioctyltin dilaurate was added to the resulting dispersion to obtain an undercoat layer coating solution. This coating solution was applied onto an aluminum substrate having a diameter of 84 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer having a thickness of 20 μm.

  Next, hydroxygallium phthalocyanine is used as a charge generating material on the aluminum base, 15 parts by mass thereof, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and n- A mixture consisting of 300 parts by mass of butyl alcohol was dispersed for 4 hours in a sand mill. The obtained dispersion was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  next. Tetrohydro with 42 parts by mass of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine and 58 parts by mass of bisphenol Z polycarbonate resin (TS2050: viscosity average molecular weight 50,000: manufactured by Teijin Chemicals Ltd.) A coating solution sufficiently dissolved and mixed in 280 parts by mass of furan and 120 parts by mass of toluene is dip-coated on an aluminum support coated up to the charge generation layer, and dried at 135 ° C. for 40 minutes. A transport layer was formed.

  Next, the exemplified compound (I-11): 50 parts by mass, the exemplified compound (I-16): 50 parts by mass, the melamine compound represented by the formula (B) -8: 1 part by mass, t-butyl alcohol (BuOH): Dissolved in 200 parts by mass. The obtained coating solution was dip coated on an aluminum support coated up to the charge transport layer and dried at 150 ° C. for 40 minutes to form a protective layer having a thickness of 5 μm.

The electrophotographic photoreceptor 1 was produced as described above.
The obtained electrophotographic photosensitive member 1 was laminated and packed using a desktop degassing sealer V-300 (manufactured by Fuji Impulse Co., Ltd.). Specifically, the electrophotographic photosensitive member 1 is degassed using a packaging film (a laminate film obtained by laminating PET, Al foil, and heat-resistant CPP) 24 hours after the production, and the ultimate vacuum is as the deaerated state. : 320 torr) and laminated.
And after the laminate pack, it was stored for 7 days at 25 ° C./50% normal temperature and humidity.

-Evaluation-
Evaluation was made by XPS analysis and comparing the amount of surface oxygen on the surface of the photoreceptor immediately after fabrication of the photoreceptor (within 24 hours after fabrication, the same hereinafter) and after storage.
Immediately after fabrication of the photoreceptor and after storage, a patch (rectangular 6 cm in the circumferential direction and 20 cm in the axial direction) is applied to the center of the photoreceptor surface, and the patch is exposed to white light (light quantity 620 Lux) for 10 minutes. The image was formed on Docu Center-II C7500 manufactured by Xerox Co., Ltd., and image formation was performed on A3 paper having an image density of 50% at room temperature and humidity of 25 ° C./50%, and image density unevenness was compared. All parts except the patch were protected with black paper. The results are also shown in Table 1.
The evaluation criteria are as follows.

-Image density unevenness evaluation criteria-
○: There is no difference in density unevenness after comparing the image density unevenness immediately after preparation of the photoconductor and after storage, and Δ: There is a slight difference in density unevenness when comparing the image density unevenness immediately after preparation of the photoconductor and after storage. .
X: Comparison of image density unevenness immediately after production of the photoconductor and after storage has elapsed, and there is a large difference in density unevenness, which is aggravated.

(Example 2)
The electrophotographic photosensitive member 1 was produced in the same manner as in Example 1, laminated and then stored for 14 days at 25 ° C./50% normal temperature and humidity.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
The electrophotographic photoreceptor 1 was prepared in the same manner as in Example 1 and laminated and then stored for 30 days at 25 ° C./50% normal temperature and humidity.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 4
The electrophotographic photosensitive member 1 was produced in the same manner as in Example 1, laminated and then stored for 90 days at 25 ° C./50% normal temperature and humidity.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
An electrophotographic photosensitive member 2 is produced in the same manner as in Example 1 except that the amount of the melamine compound represented by the formula (B) -8 is changed to 4.8 parts by mass in the production of the protective layer in Example 1. In addition, after laminating and packing, it was stored at 25 ° C./50% normal temperature and humidity for 90 days.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
In the production of the protective layer in Example 1, melamine compound: 1 part by mass The electrophotographic photosensitive member 3 was prepared in the same manner as in Example 1 except that the guanamine compound represented by the formula (A) -14 was changed to 1 part by mass. And laminated pack, and then stored for 90 days at 25 ° C./50% normal temperature and humidity.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
An electrophotographic photosensitive member 1 is produced in the same manner as in Example 1, and then laminated in an atmosphere at room temperature and humidity of 25 ° C./50%, and left as it is at room temperature and humidity of 25 ° C./50%. Stored for 7 days.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
The electrophotographic photosensitive member 1 was produced in the same manner as in Example 1, and then stored for 14 days at 25 ° C./50% normal temperature and humidity without performing a laminate pack.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
The electrophotographic photoreceptor 1 was produced in the same manner as in Example 1, and then stored for 30 days at 25 ° C./50% normal temperature and humidity without performing a laminate pack.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
An electrophotographic photosensitive member 4 is produced in the same manner as in Example 1 except that the amount of the melamine compound represented by the formula (B) -8 is changed to 5.5 parts by mass in the production of the protective layer in Example 1. In addition, after laminating and packing, it was stored at 25 ° C./50% normal temperature and humidity for 90 days.
Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

  From the above results, it can be seen that in this embodiment, the occurrence of uneven image density is suppressed even after storage over time, as compared with the comparative example.

DESCRIPTION OF SYMBOLS 1 Undercoat layer, 2 Charge generation layer, 3 Charge transport layer, 4 Conductive support body, 5 Surface protective layer, 6 Single layer type photosensitive layer, 10 Electrophotographic photoreceptor, 11 Case, 20 Charging device, 30 Exposure device , 40 Developing device, 41 Developing roll, 50 Transfer device, 60 Fixing device, 70 Cleaning device, 71 Housing, 72 Cleaning blade, 72A Support member, 73 Cleaning brush, 74 Lubricant, 101A Process cartridge, 101 Image forming device

Claims (5)

A conductive substrate, a photosensitive layer provided on the conductive substrate,
A surface protective layer provided on the photosensitive layer;
Have
The surface protective layer includes at least one compound selected from a guanamine compound and a melamine compound, and at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. And at least one compound selected from the guanamine compound and the melamine compound is contained in an amount of 0.1% by mass or more and 5% by mass or less. ,
In addition, when the electrophotographic photosensitive member is packaged, an electrophotographic photosensitive member having a surface oxygen amount of 4 atm% or more and 8 atm% or less by X-ray photoelectron spectroscopy measurement (XPS measurement) in the surface protective layer after the package is opened. The electrophotographic photosensitive member according to claim 1, wherein the charge transporting material is a compound represented by the following general formula (I).
^{F - ((- R 13 -X} ) n1 (R 14) n2 -Y) n3 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, and R ¹³ and R ¹⁴ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, n3 represents an integer of 1 to 4, X represents an oxygen, NH, or sulfur atom, Y represents —OH, —OCH ₃ , _-NH 2, shown -SH, or -COOH.) A conductive substrate; a photosensitive layer provided on the conductive substrate; and a surface protective layer provided on the photosensitive layer, wherein the surface protective layer is selected from a guanamine compound and a melamine compound. A cross-linked product of at least one compound and at least one charge transporting material having at least one substituent selected from —OH, —OCH ₃ , —NH ₂ , —SH, and —COOH. And an electrophotographic photoreceptor containing at least one compound selected from the guanamine compound and the melamine compound in an amount of 0.1% by mass to 5% by mass,
When the process cartridge is packaged, the amount of surface oxygen by X-ray photoelectron spectroscopy (XPS measurement) in the surface protective layer after opening the package is 4 atm% or more and 8 atm% or less,
A process cartridge that is detachable from the image forming apparatus. The process cartridge according to claim 3, wherein the charge transporting material is a compound represented by the following general formula (I).
^{F - ((- R 13 -X} ) n1 (R 14) n2 -Y) n3 (I)
(In general formula (I), F is an organic group derived from a compound having a hole transporting ability, and R ¹³ and R ¹⁴ are each independently a linear or branched alkylene group having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents 0 or 1, n3 represents an integer of 1 to 4, X represents an oxygen, NH, or sulfur atom, Y represents —OH, —OCH ₃ , _-NH 2, shown -SH, or -COOH.) The electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the electrophotographic photoreceptor;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for containing a developer containing toner and developing the electrostatic latent image formed on the electrophotographic photosensitive member into a toner image by the developer;
Transfer means for transferring the toner image to a transfer object;
An image forming apparatus comprising: