JP2000010322A - Electrophotographic photoreceptor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the wear resistance and printing resistance without loosing photosensitive characteristics such as chargeability, sensitivity and the like and applicability by including a cross-linked organic fine particle having a specified average particle size in the surface layer of a photoreceptor. SOLUTION: As a cross-linked fine particle used in the surface layer of a photoreceptor, a one having an average particle size of 1 μm or less is preferred and, particularly, a one containing the particles 1 μm or less in a ratio of about 95 wt.% or more is preferably used. The cross-linked fine particle generally consists of a cross-linked polymer, which is obtained by polymerizing a polymeric monomer containing a cross-linkable monomer. As the cross-linkable monomer, a compound having two or more copolymerizable double bonds or a non-conjugate divinyl compound as polyvalent acrylate is used. A photosensitive layer 2 is laminated on a conductive support 1. The conductive support 1 is formed of, for example, aluminum, stainless steel, copper, nickel, zinc or the like. The charge generating agent included in the photosensitive layer 2 consists of selenium and its alloy, arsenic-selenium, cadmium sulfide or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member having excellent printing durability and used in a copying machine, a printer, and the like using an electrophotographic process.

[0002]

2. Description of the Related Art In an electrophotographic image forming method based on the Carlson method, after uniformly charging a surface of a photoreceptor, the charge is eliminated by performing exposure in accordance with image information forming the surface. An electrostatic latent image is formed on the surface.
Next, the electrostatic latent image is developed and visualized with toner, and the toner image is transferred from a photoreceptor to a transfer paper or the like and then fixed. On the other hand, the surface of the photoreceptor after the transfer is initialized by removing toner remaining on the surface, removing static electricity, and the like, and is used repeatedly.

Accordingly, the electrophotographic photoreceptor is required to have photosensitive characteristics such as good charging characteristics and sensitivity and low dark decay characteristics, and to have printing durability, abrasion resistance, scratch resistance and the like when repeatedly used. It is also required to have good mechanical properties, active species such as ozone generated during corona discharge, and good resistance to ultraviolet rays during exposure. For electrophotographic photoreceptors,
Inorganic photoconductive materials such as selenium, selenium-tellurium alloy, arsenic selenide, cadmium sulfide, and zinc oxide have been widely used. In addition, an organic photoconductive material having characteristics of low pollution and easy production is widely used for a photosensitive layer. In particular, a stacked photoreceptor composed of a charge generation layer and a charge transfer layer in which the function of generating charge by absorbing light and the function of transporting the generated charge are separated has become mainstream. These photoconductors are widely used in fields such as copying machines and laser printers.

In recent years, in electrophotographic copying machines and printers, it has been demanded that a large amount of images can be formed quickly and that maintenance is not troublesome. In particular, organic photoreceptors have the disadvantage that they have poorer mechanical properties than inorganic photoreceptors and are liable to be worn and damaged when used repeatedly. Various studies have been made to improve such disadvantages.
Decreasing the amount of charge transport material reduces the amount of wear, but degrades the photosensitivity. As another means, when the molecular weight of the binder in the charge transport layer increases, the amount of wear decreases, but the viscosity of the coating solution increases, so that defects such as sagging and unevenness are likely to occur at the coating stage. Recently, a method of dispersing inorganic fillers and lubricating particles in the charge transport layer has been devised.However, since the incident light is scattered by the particles, the sensitivity is greatly degraded, or the dispersed particles in the coating liquid are left unattended. However, at present, there is no electrophotographic photoreceptor having improved mechanical properties without deteriorating properties such as photosensitive properties and coating properties.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce wear during long-term repeated use, to provide excellent cleaning properties and durability against scratches, An object of the present invention is to provide an electrophotographic photosensitive member that does not impair other characteristics such as electric characteristics and coatability.

[0006]

As a result of intensive studies on the above problems, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, specific crosslinked organic fine particles are contained in the surface layer of the photosensitive member. As a result, it has been found that abrasion resistance and printing durability can be improved without impairing photosensitive properties such as chargeability and sensitivity, and coating properties. That is, the gist of the present invention is firstly an electrophotographic photoreceptor characterized in that the surface layer of the photoreceptor contains crosslinked organic fine particles having an average particle size of 1 μm or less, and secondly, the surface layer of the photoreceptor An electrophotographic photoreceptor containing crosslinked organic fine particles including a crosslinked body of a styrene-based polymer, and thirdly, the crosslinked organic fine particles are washed, then dispersed in a coating solution, and coated with the coating solution. This is a method for producing an electrophotographic photoreceptor in which a surface layer is formed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The average particle diameter of the crosslinked organic fine particles used in the surface layer of the present photoreceptor is 1 μm or less, and particularly preferably the ratio of particles of 1 μm or less is 95% by weight or more. The crosslinked organic fine particles are generally a crosslinked polymer, and may be those obtained by, for example, thermal crosslinking without using a crosslinking agent, but generally, a polymerizable polymerizable monomer including a crosslinkable monomer is used. Is obtained by As the crosslinkable monomer, a compound having two or more copolymerizable double bonds is used, and a non-conjugated divinyl compound such as a polyvalent acrylate or divinylbenzene is used. As the polymerizable monomer, usually, vinyl monomers such as an aromatic monovinyl compound such as ethylvinylbenzene, styrene and α-methylstyrene, a vinyl cyanide compound, acrylic acid, an acrylic ester, a methacrylic ester, an acrylamide, and a carboxylic acid. Is mentioned.
Among these, a crosslinked product of a styrene polymer is preferable,
In particular, those using divinylbenzene as a crosslinking agent are preferred.

As a method for producing such fine particles, those synthesized by an emulsion polymerization method, a seed polymerization method, a soap-free emulsion polymerization method or the like are used. Emulsifiers, suspension protectants, surfactants, residual monomers, etc. used during polymerization may deteriorate the electrical properties of the photoreceptor, and have been subjected to a washing treatment to remove such surfactants. Is preferred. The washing method is obtained by washing with a solvent, filtering and drying. Examples of the washing liquid include water and organic solvents such as alcohol and acetone.

For the purpose of controlling the particle size after polymerization,
It is processed by a centrifugal separation method, a filtration method (filter, diatomaceous earth), an airflow classification method, or the like. If the added amount of the crosslinked organic fine particles is too small, there is no effect on the mechanical properties, and if the added amount is too large, the electrical properties are deteriorated or the surface of the coating film becomes uneven. Therefore, the addition amount is 0.01% to 3% based on the total solid weight of the surface layer.
A range of 0% is preferable, and 0.1% to 10% is more preferable. It is also possible to use two or more kinds of crosslinked organic fine particles having different particle diameters or the like. In the case of forming the surface layer of the present invention, the crosslinked organic fine particles are dispersed in the coating solution for the surface layer by the same method as the charge generating agent described below, and the dispersion is applied by a coating means to form a photoreceptor.

Next, the structure of the electrophotographic photosensitive member used in the present invention will be described. As the layer constitution of the present photoreceptor, those proposed as existing organic electrophotographic photoreceptors shown in FIGS. 1 to 4 can be used. In the case of a single-layer structure containing a charge generating agent and a charge transporting agent, the surface layer of the electrophotographic photoreceptor of the present invention corresponds to the entire photosensitive layer. In the case of a function separation type laminated photoreceptor in which the photosensitive layer has a charge transporting layer containing a charge transporting agent on a charge generating layer containing a charge generating agent, the charge transporting layer corresponds to the surface layer. In the case of a function inversion type photoconductor in which a charge generation layer is provided on a charge transport layer, the charge generation layer becomes a surface layer. Further, a protective layer can be provided on the photosensitive layer. In this case, the protective layer corresponds to the surface layer. FIG.
Shows an example of a two-layer type.

The photosensitive layer is laminated on a conductive support,
The conductive support is, for example, aluminum, stainless steel,
Metal materials such as copper, nickel, zinc, indium, gold, and silver; polymers such as polyester having a conductive layer such as aluminum, copper, palladium, tin oxide, indium oxide, and conductive polymers, paper, and glass; , And the like. The surface of the conductive support can be subjected to various treatments within a range that does not affect the image quality. For example, surface oxidation treatment or chemical treatment can be performed. A metal drum or the like that has been subjected to a metal oxidation treatment by electrode oxidation or the like corresponds to this.
The shape can take any shape such as a drum, a sheet, a belt, and a seamless belt.

As the charge generating agent contained in the photosensitive layer,
Selenium and its alloys, arsenic-selenium, cadmium sulfide,
Alloys such as zinc oxide, cadmium sulfide, zinc oxide, antimony sulfide, Cd-Se, oxide semiconductors such as titanium oxide, silicon materials such as amorphous silicon, other inorganic photoconductive materials, phthalocyanine, azo dyes, quinacridone And various organic pigments and dyes such as polycyclic quinone, pyrylium salt, perylene, indigo, thioindigo, anthantrone, pyranthrone and cyanine. Among them, metal-free phthalocyanine, copper, indium chloride, gallium chloride, silicon, tin, oxytitanium,
Metals such as zinc and vanadium, or oxides, chlorides, phthalocyanines coordinated with hydroxides, or monoazos,
Azo pigments such as bisazo, trisazo and polyazos are desirable. These charge generating agents can be used alone or in combination of two or more.

The charge generating agent contained in the photosensitive layer includes:
Polymer compounds such as polyvinylcarbazole, polyvinylpyrene, polyacenaphthylene, polyvinylpyrene, polyvinylanthracene, or various pyrazoline derivatives, carbazole derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, arylamine derivatives, oxadiazole derivatives, thiazole derivatives And low molecular compounds such as thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, styryl compounds, benzothiazole derivatives, benzimidazole derivatives, acridine derivatives, and phenazine derivatives. In addition to the above-described hole transport type charge transport agents, electron transport agents such as benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, and fluorenone derivatives are also used as necessary. These charge transporting agents are used singly or in combination of two or more in consideration of the combination with the charge generating agent, the polarity and the like.

When the charge generating agent and the charge transporting agent contained in the photosensitive layer have poor film-forming ability, they may be formed using a binder polymer. In this case, the charge generation layer can be obtained by applying and drying a coating solution obtained by dissolving or dispersing these substances and a binder polymer in a solvent.
Examples of the binder include polymers and copolymers of vinyl compounds such as butadiene, styrene, vinyl acetate, vinyl chloride, acrylates, methacrylates, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide, and polyurethane. , Cellulose ether, phenoxy resin, silicon resin, epoxy resin and the like, and polycarbonate is particularly preferable. These can be used after being crosslinked by heat, light or the like using an appropriate curing agent or the like. These binders can be used alone or in combination of two or more.

In the case of the function-separated type photoreceptor, the ratio of the charge generating agent to the binder polymer in the charge generating layer is not particularly limited, but is generally 5 to 500 parts by weight, based on 100 parts by weight of the charge generating agent. Preferably, 20 to 300 parts by weight of a binder polymer is used. Charge generators are usually ball mills, ultrasonic dispersers, paint shakers,
Disperse and dissolve in an appropriate dispersion medium with an attritor, sand grinder, etc., adjust the coating solution by adding a binder resin as necessary, and dipping the coating solution, spraying method, bar coater method, blade method, The coating is performed by a coating method such as a roll coater method, a wire bar coating method, and a knife coater coating method, and then dried. Further, the charge generation layer may be formed by depositing the above-mentioned charge generation agent by a vapor deposition method such as vapor deposition or sputtering. The thickness of the charge generation layer is 0.
The thickness is set to 01 to 5 μm, preferably 0.05 to 2 μm.

The ratio of the charge transporting agent to the binder polymer in the charge transporting layer is not particularly limited, but is generally 10 to 500 parts by weight with respect to 100 parts by weight of the charge transporting agent.
Preferably, 30 to 300 parts by weight of a binder polymer is used. The charge transport layer is mixed with the above polymer having excellent performance as a binder, dissolved in an appropriate solvent together with the charge transport agent, and the obtained coating solution is applied by the same method as the charge generation layer, Can be manufactured. The thickness of the charge transport layer is usually 10 μm to 50 μm,
Preferably, it is used in a range of 13 μm to 35 μm.

When the photosensitive layer has a single-layer structure, a coating solution obtained by dissolving and dispersing additives and the like in addition to the above-described charge generating agent, charge transporting agent, binder polymer, crosslinked organic fine particles in a solvent is applied to the substrate by the same method. A photosensitive layer is obtained by coating on the top. Solvents and dispersion media used for coating include butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, and 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, etc. Can be One of these solvents may be used alone, or two or more thereof may be used as a mixed solvent.

If necessary, an electron-withdrawing compound or a pigment, a dispersant, a surfactant or other additives may be added. Examples of the electron-withdrawing compound include cyano compounds such as tetracyanoquinodimethane, dicyanoquinomethane, and aromatic esters having a dicyanoquinovinyl group;
Nitro compounds such as 4,6-trinitrofluorenone; condensed polycyclic aromatic compounds such as perylene; diphenoquinone derivatives; quinones; aldehydes; ketones;
Acid anhydrides; phthalides; substituted and unsubstituted salicylic acid metal complexes; substituted and unsubstituted salicyl metal salts; aromatic carboxylic acid metal complexes; aromatic carboxylic acid metal salts. Preferably, cyano compounds, nitro compounds, condensed polycyclic aromatic compounds, diphenoquinone derivatives, metal complexes of substituted and unsubstituted salicylic acids, metal salts of substituted and unsubstituted salicylic acids; metal complexes of aromatic carboxylic acids; It is preferable to use a metal salt. When the binder resin is polycarbonate, a polystyrene-polycarbonate block copolymer is preferable as the dispersant. The polystyrene-polycarbonate block copolymer is obtained by introducing a group having a double bond at the terminal of a polycarbonate resin and copolymerizing a styrene monomer in the presence of a polycarbonate having a double bond at the terminal.

Further, the photosensitive layer of the electrophotographic photosensitive member of the present invention is a well-known plasticizer and antioxidant for improving film forming property, flexibility, coating property, mechanical strength, film forming property, durability and the like. , An ultraviolet absorber and a leveling agent. The photoreceptor thus formed may have an undercoat layer,
Needless to say, an intermediate layer, a transparent insulating layer, a surface protective layer and the like may be provided. The undercoat layer is usually used between the photosensitive layer and the conductive support (FIG. 5), and a commonly used known layer can be used. Examples of the undercoat layer include polyamide resin, phenol resin, melamine resin, casein, polyurethane resin, epoxy resin, cellulose, nitrocellulose, polyvinyl alcohol, polyvinyl butyral, and the like, or titanium oxide, aluminum oxide, zirconia, oxidized An inorganic fine particle such as silicon or an organic fine particle such as an azo pigment dispersed therein can be used. These fine particles and resin can be used alone or in combination of two or more. The thickness is usually 0.01
To 50 μm, preferably 0.01 to 10 μm. A known blocking layer can be provided between the photosensitive layer and the conductive support.

When a surface protective layer is provided on the photoreceptor, the thickness of the protective layer can be 0.01 to 20 μm, preferably 0.1 to 10 μm. The above-mentioned binder can be used for the protective layer, but the protective layer may contain the above-mentioned charge generating agent, charge transporting agent, additive, conductive material such as metal and metal oxide. The protective layer may contain wax, and the amount of the wax added is usually 0.01 to 30% by weight, preferably 0.1 to 10% by weight. The electrophotographic photoreceptor thus obtained is a photoreceptor that maintains excellent printing durability over a long period of time, and is suitable for electrophotographic fields such as copying machines, printers, fax machines, and plate making machines.

In using the electrophotographic photoreceptor of the present invention, a corona charger such as a corotron and a scorotron, and a contact charger such as a charging roll and a charging brush are used. Exposure is performed using a halogen lamp, a fluorescent lamp, a laser (semiconductor, He-Ne, etc.), an LED, a photoconductor internal exposure system, or the like. For the development process, a dry development system such as a cascade development, a one-component insulation toner development, a one-component conductive toner development, a two-component magnetic brush development, a wet development system, or the like is used. For the transfer process, an electrostatic transfer method such as corona transfer, roller transfer, belt transfer, pressure transfer method, and adhesive transfer method are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing and the like are used. For cleaning, brush cleaner, magnetic brush cleaner,
An electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, and the like are used.

[0022]

The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto unless it exceeds the gist thereof. In the examples, "part"
"" Means "parts by weight".

Example 1 (Preparation of charge generation layer) Azo compound 10 having the following structure
Part is 150 parts of 4-methoxy-4-methylpentanone-
In addition to the above, pulverization and dispersion treatment was performed with a sand glide mill. The pigment dispersion obtained here was treated with polyvinyl butyral (trade name # 6000-C, manufactured by Denki Kagaku Kogyo KK).
%, 1,2-dimethoxyethane solution 100 parts and phenoxy resin (PKHH, manufactured by Union Carbide)
Was added to a mixture of 100 parts of a 5% dimethoxyethane solution to finally prepare a dispersion having a solid concentration of 4.0%.

[0024]

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This charge generation layer solution was applied by dip coating to an aluminum cylinder, and its dry film thickness was 0.4 g / m 2 (about 0.4 g / m 2).
μm). (Preparation of Charge Transfer Layer) Next, on this charge generation layer, 95 parts of the following charge transfer material (hereinafter abbreviated as CTM) (T-1) were added.

[0026]

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1.5 parts of the following cyano compound:

[0028]

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Particles having an average particle size of 0.5 μm obtained by crosslinking polystyrene with divinylbenzene as crosslinked organic non-particles (product name: SX8742 (D) -0, manufactured by JSR Corporation)
5) 5 parts of (P-1) and 100 parts of a polycarbonate resin (trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) are dispersed together with a mixed solvent of tetrahydrofuran and dioxane using alumina balls, and then ultrasonically dispersed. After dip coating, the solution was dried at 125 ° C. for 25 minutes, and a charge transfer layer was provided so that the dry film thickness became 21 μm. The electrophotographic photosensitive member thus obtained is designated as A1.

Example 2 Particles having an average particle diameter of 0.3 μm (P-
A photoconductor was prepared in the same manner as in Example 1, except that 2) was used. This electrophotographic photosensitive member is designated as A2.

Example 3 A photoconductor was prepared in the same manner as in Example 1, except that the number of crosslinked organic fine particles was changed to 10 parts. This electrophotographic photosensitive member is designated as A3.

Example 4 (Washing of Particles) 20 g of the crosslinked organic fine particles (P-1) were ultrasonically dispersed in 300 g of pure water, and the particles were collected by filtration. After this operation was performed twice, the particles were washed with acetone and dried to obtain washed particles (P-3). (Preparation of Photoconductor) A photoconductor was prepared in the same manner as in Example 1, except that P-3 was used as the crosslinked organic fine particles. This electrophotographic photosensitive member is designated as A4.

Comparative Example 1 A photoconductor was prepared in the same manner except that no crosslinked organic fine particles were used. This electrophotographic photosensitive member is designated as R1.
Next, these electrophotographic photosensitive members were mounted on a commercially available copying machine (SF7850 manufactured by Sharp Corporation), and a copy test of 30,000 sheets was performed. Table 1 shows changes in the thickness of the photosensitive layer and visual image evaluation at this time.

Example 5 A 75 μm-thick polyester film obtained by evaporating aluminum was used as a conductive support, and the charge-generating layer liquid weighed 0.4 g / m 2 (about 0.4 μm) after drying. Was applied with a wire bar and dried to form a charge generation layer. The same charge transfer layer solution as in Example 1 was applied on the charge generation layer with an applicator except that CTM (T-1) was 100 parts and the cyano compound was 0 parts, and then applied at 125 ° C. for 30 minutes at room temperature. For 20 minutes, and a charge transfer layer was provided so that the film thickness after drying was 20 μm. This electrophotographic photosensitive member is designated as A5.

Example 6 A photoconductor was prepared in the same manner as in Example 5, except that (P-2) was used as the crosslinked organic fine particles. This electrophotographic photosensitive member is designated as A6.

Example 7 A photoconductor was prepared in the same manner as in Example 5, except that the number of added crosslinked organic fine particles was changed to 10 parts. This electrophotographic photosensitive member is designated as A7.

Example 8 A photoconductor was prepared in the same manner as in Example 5, except that (P-3) was used as the crosslinked organic fine particles. This electrophotographic photosensitive member is designated as A7.

Comparative Example 2 A photoconductor was prepared in the same manner as in Example 5 except that no crosslinked organic fine particles were used. This electrophotographic photoreceptor is
Let it be 2.

Example 9 (Preparation of charge generation layer) 10 parts of oxytitanium phthalocyanine having a main peak at 27.3 ° at a Bragg angle 2θ (± 0.3 °) by powder X-ray diffraction using CuKα ray,
1,2-Dimethoxyethane 50 was added to 5 parts of polyvinyl butyral (trade name: # 6000-C, manufactured by Denki Kagaku Kogyo KK).
0 parts were added, and the mixture was pulverized and dispersed by a sand grind mill to obtain a charge generation layer liquid. Next, a film obtained by evaporating aluminum on a 75 μm-thick polyester film was used as a conductive support, and the charge-generating layer had a weight of 0.4% after drying.
g / m2 (approximately 0.4 .mu.m) with a wire bar and dried to form a charge generating layer.

(Preparation of Charge Transfer Layer) Next, 56 parts of the following CTM (T-2) were formed on this charge generation layer.

[0041]

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CTM (T-3) 14 parts shown below

[0043]

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Particles having an average particle size of 0.5 μm obtained by crosslinking polystyrene with divinylbenzene as crosslinked organic fine particles (manufactured by JSR Corporation, trade name SX8742 (D) -0)
5) 5 parts of (P-1) and 100 parts of a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Z-200) were dispersed in a mixed solvent of tetrahydrofuran and dioxane using alumina balls, and then ultrasonically dispersed. After dip-coating the solution, drying at 125 ° C. for 25 minutes,
The charge transfer layer was provided so that the dry film thickness became 20 μm. The electrophotographic photosensitive member thus obtained is designated as A9.

Comparative Example 3 A photoconductor was prepared in the same manner as in Example 9 except that no crosslinked organic fine particles were used. This electrophotographic photoreceptor is
3 is assumed. Next, these electrophotographic photoreceptors were mounted on a photoreceptor characteristic measurement [Model EPA8100 manufactured by Kawaguchi Electric Co., Ltd.], and charged so that the current flowing into the aluminum surface became 50 μA. Example 9, Comparative Example 3
Is a monochromatic light exposure of 780 nm), charge is removed, the chargeability (Vo) at that time, the rate of decrease in potential (dark decay DD) after leaving for 2 seconds from the start of charging, the amount of half-decreased exposure (E1 / 2) Reference potential:
−450 V, lux · sec for white light, μJ / cm 2 for 780 nm) Residual potential (Vr) was measured. Furthermore, the wear wheel (CS-10) was measured using a taper wear tester.
Using F), the decrease in abrasion weight after 1000 rotations was measured. Table 2 shows the results.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

According to the present invention, there is little abrasion in repeated use over a long period of time, and the cleaning property and the durability against scratches are excellent, and other properties such as electric properties and coating properties are not impaired.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a single-layer type electrophotographic photosensitive member.

FIG. 2 is an explanatory diagram of a function-separated type laminated photoconductor.

FIG. 3 is an explanatory diagram of a function inversion type laminated photoconductor.

FIG. 4 is an explanatory view showing an example of a photoconductor having a surface protective layer.

FIG. 5 is an example of an embodiment for explaining an undercoat layer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 photosensitive layer 3 charge generation layer 4 charge transport layer 5 undercoat layer 6 surface protective layer

Continuation of the front page (72) Inventor Satoshi Kato 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture F-term in Yokohama Research Laboratory, Mitsubishi Chemical Corporation 2H068 AA03 AA04 BB10 BB20 BB25 BB54 BB57 FA01 FA03 FB01 FB05

Claims (7)

[Claims] 1. An electrophotographic photoreceptor comprising a surface layer containing crosslinked organic fine particles having an average particle diameter of 1 μm or less. 2. The electrophotographic photoreceptor according to claim 1, wherein the crosslinked organic fine particles have a particle diameter of 1 μm or less in an amount of 95% by weight or more. 3. An electrophotographic photoreceptor, wherein the surface layer contains crosslinked organic fine particles containing a crosslinked product of a styrene-based polymer. 4. The electrophotographic photoreceptor according to claim 3, wherein the crosslinked styrene polymer is a crosslinked styrene polymer crosslinked with divinylbenzene. 5. The method according to claim 1, wherein the binder resin of the surface layer is polycarbonate.
13. The electrophotographic photoreceptor according to item 6. 6. The electrophotographic photoreceptor according to claim 3, wherein the binder resin of the surface layer is polycarbonate and further contains a polystyrene-polycarbonate block copolymer. 7. A method for producing an electrophotographic photoreceptor, comprising washing a crosslinked organic fine particle, dispersing it in a coating solution, and applying the coating solution to form a surface layer.