JPH04345167A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent the lowering of the surface resistance of an electrophotographic sensitive body due to the sticking of paper dust, etc., to the surface at the time of repeated use and to also prevent the running of an image. CONSTITUTION:An electric charge transferring layer, an electric charge generating layer, a protective layer and a surface lubricative layer are successively laminated on an electric conductive substrate to form an electrophotographic sensitive body. The protective layer contains thermosetting silicone resin, urethane elastomer and hydrophobic silica and has 0.01-0.5mum average surface roughness along the center line. The lubricative layer has 0.01-0.5mum. The sensitive body has sensitivity when positively charged, is stable to temp. and humidity and prevents the running of an image due to the lowering of the surface resistance at high temp. and humidity caused by surface deposits such as paper dust especially after repeated use. Even if the protective layer is thin, the sensitive body has high hardness, high film strength, excellent wear resistance and durability.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor containing an organic photoconductive substance, and more particularly to a laminated electrophotographic photoreceptor used for positive charging.

0002

[Prior Art] In the past, photoreceptors made of inorganic photoconductive materials such as selenium, selenium-tellurium alloy, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors. Research is progressing on organic photoconductive materials, which have characteristics such as the ability to select compounds that exhibit photoconductivity in an appropriate wavelength range.

Electrophotographic photoreceptors using organic photoconductive substances in their photosensitive layers have advantages such as easy film formation, high flexibility and a large degree of freedom in design, low cost, and non-polluting properties. However, the sensitivity and photoreceptor life were inferior compared to inorganic photoconductive materials. In order to improve these problems, a laminated electrophotographic photoreceptor in which a photosensitive layer is formed by separating the functions of a charge generation layer and a charge transport layer has been proposed and put into practical use. Since the charge transport agent generally used in this laminated electrophotographic photoreceptor is an electron-donating substance such as pyrazoline, hydrazone, or oxazole, the charge transport layer is of a hole transport type, and therefore a charge transport layer is formed on the charge generation layer. When laminated, it is used with a negative charge.

On the other hand, these electrophotographic photoreceptors are usually repeatedly subjected to the processes of charging, exposure, development, transfer, cleaning, and static elimination, but in this series of processes, positive charging is faster than negative charging. Corona discharge is stable, and the amount of ozone generated is small, so there is little property deterioration due to ozone oxidation. In addition, conventionally used inorganic photoreceptors such as selenium and selenium-tellurium alloys are used with a positive charge, so there is a strong demand for an organic photoreceptor that can be used with a positive charge because these electrophotographic processes can be shared.

[0005] In order to obtain a positive charge with a structure in which a charge transport layer is stacked on a normal charge generation layer, an electron-accepting substance such as trinitrofluorenone may be used as a charge transport agent. Receptive substances are not generally used because they are rarely available with high mobility, are chemically unstable, and have harmful effects such as carcinogenicity. Therefore, in order to enable positive charging using an electron donating substance, a structure has been proposed in which a charge transport layer and a charge generation layer are laminated in this order on a conductive support. They have drawbacks such as large carrier injection into the charge transport layer, which reduces chargeability, and generally because the charge generation layer is a thin layer, mechanical strength is low and durability is poor.

Therefore, we have proposed a three-layer structure in which a protective layer of a thin resin film is further provided on the charge transport layer and charge generation layer, or a four-layer structure consisting of a charge transport layer, a charge generation layer, a charge injection blocking layer, and a surface protection layer. Proposal of the structure, as well as the charge transport layer and charge generation layer.
In the layer structure, increase the resin ratio of the charge generation layer to 5μm.
Proposals have been made to improve mechanical strength by increasing the thickness of the charge generation layer, and to maintain sensitivity by adding a charge transport agent to the charge generation layer. (For example, The Third International Congress on Advances
Innon Impact Printing Technologies: The 3rd international
congress on advances in n
on-impact printing technology
logies proceedings p115, Electrophotographic Society No. 59
Proceedings of the Annual Research Conference, p. 184, etc.) In the case of resin thin films, polyester resins, polyvinyl butyral resins, phenolic resins, cellulose acetate, styrene-maleic anhydride copolymers, polyamide resins, polyimide resins, and melamine resins are generally used as protective layers for photoreceptors. etc. (for example, Japanese Patent Publication No. 38-15446, Japanese Patent Publication No. 51-15748, Japanese Patent Publication No. 52-24414, Japanese Patent Publication No. 56-34
860, Japanese Patent Publication No. 56-53756, Japanese Patent Publication No. 60-55357, Japanese Patent Publication No. 61-22345, etc.); It cannot be said to be sufficient in terms of stability, and there is a problem of image blurring or image blurring due to a decrease in surface resistance under high temperature and high humidity conditions, especially due to surface deposits such as paper dust after repeated use.

[0007] In addition, these protective layers made of thin resin films do not have sufficient durability when they are thin, and on the other hand, when the film thickness is increased, the residual potential increases and the repeatability characteristics deteriorate.

[0008] Therefore, a method of using a protective layer in which a metal oxide is dispersed in a binder resin (for example,
Special Publication No. 57-39846, Special Publication No. 58-1210
44, Japanese Patent Publication No. 59-223445, etc.), however, metal oxides in the binder resin are insoluble in the binder resin and solvent, and their shape is lumpy, so they may not be present in the protective layer. Even if the content is constant, the resistance value will fluctuate depending on the dispersion state, making the characteristics unstable. Also, unless the blending ratio, particle size, etc. are carefully controlled, environmental fluctuations in chargeability and residual potential, It has the disadvantage of causing repeated fluctuations.

[0009]

[Problem to be solved by the invention] Therefore, in any case, there have not been many satisfactory characteristics in terms of sensitivity, durability, etc., and only high durability against scratches and abrasion during repeated use has been obtained. In addition, it has less surface resistance reduction due to surface deposits such as paper dust, is stable in use environments such as temperature and humidity, can be used with positive charge, and satisfies the characteristics required as an electrophotographic photoreceptor. It is desired to develop an electrophotographic photoreceptor with a long life.

0010

[Means for Solving the Problems] In view of the above-mentioned problems, the present invention provides a structure in which a charge transport layer, a charge generation layer, a protective layer, and a surface lubricating layer are laminated in this order on a conductive support. contains thermosetting silicone resin, urethane elastomer, and hydrophobic silica, and its surface roughness is 0 in terms of center line average roughness.
．． The electrophotographic photoreceptor has a surface lubricating layer of 0.01 μm or more and 0.5 μm or less, and is sensitive to positive charging and stable against temperature and humidity, especially after repeated use. There is no image blurring due to a decrease in surface resistance due to surface deposits such as paper dust under high temperature and high humidity conditions, and even with a thin protective layer, the hardness and film strength are high, making it an electronic film with excellent abrasion resistance and durability. The present invention provides a photographic photoreceptor.

[0011]

[Function] The electrophotographic photoreceptor of the present invention is positively charged and sensitive by laminating a charge transport layer, a charge generation layer, a protective layer, and a surface lubricant layer in this order on a conductive support.

Further, in the electrophotographic photoreceptor of the present invention, by using a thermosetting silicone resin as a protective layer, a coating film with high hardness and excellent light transmittance and weather resistance can be obtained. At the same time, by containing urethane elastomer, wear resistance is improved and
It prevents the inherent moisture permeability of silicone resin, stabilizes the resistance of the protective layer under high temperature and high humidity conditions, and improves image fading.

Furthermore, by containing the urethane elastomer, it is possible to prevent cracks caused by curing shrinkage of the silicone resin during film formation and to improve adhesion to the lower layer.

[0014] The electrophotographic photoreceptor of the present invention includes the following in the protective layer:
In addition to the thermosetting silicone resin and urethane elastomer, it also contains hydrophobic silica to improve the hardness of the photoreceptor surface, reduce the surface friction coefficient, and increase the durability and toner filming resistance of the photoreceptor. can.

[0015] The silica contained at the same time must be hydrophobic, and by being hydrophobically treated, it prevents the adsorption of ions such as moisture and ozone products, and improves image blurring under high temperature and high humidity conditions. It is something that can be done.

Furthermore, the silica contained at the same time makes the surface roughness of the protective layer 0.01 μm or more and 0.5 μm or less in terms of center line average roughness, and furthermore, the surface lubricant layer has a center line average roughness of 0.01 μm or more and 0.5 μm or less. By setting the thickness to 01 μm or more and 0.5 μm or less, even a resin film with poor mechanical strength can be used as a surface lubricating layer.

The electrophotographic photoreceptor of the present invention improves the lubricity of the photoreceptor surface by further laminating a surface lubricating layer on the protective layer with a thickness comparable to the surface roughness of the protective layer.
By reducing the adhesion of surface deposits to the protective layer, it improves the effectiveness of cleaning devices such as urethane blades, prevents image fading due to decreased surface resistance due to deposits such as paper dust during repeated use, and improves the effectiveness of cleaning devices such as urethane blades. This makes it possible to significantly improve the service life.

[0018]

EXAMPLES The electrophotographic photoreceptor of the present invention will be explained in detail below.

The thermosetting silicone resin used in the protective layer of the electrophotographic photoreceptor of the present invention is one obtained by thermosetting a hydrolyzate of alkoxysilane, and the hydrolyzate is trifunctional or tetrafunctional. Any alkyl group may be used as long as it has a silanol group, and examples of the alkyl group include a methyl group.

These thermosetting silicone resins are preferably those that are soluble in alcoholic solvents as a hydrolyzate of alkoxysilane, can be applied without corroding the lower layer, and can be condensed by heat treatment after forming the coating. It hardens to produce a highly hard and durable film.

Similarly, the urethane elastomer contained in the protective layer is preferably one that is soluble in alcoholic solvents because it does not corrode the underlying layer.

[0022] The alcohol-soluble urethane elastomer is
After condensation of isocyanate and an equivalent excess of polyol in a low-boiling solvent such as acetone, n-hexane, or ethyl acetate, 1-propanol, 2-propanol, 1-butanol, or It can be obtained by replacing it with an alcoholic solvent containing at least one selected from 2-butanol, 2-methylpropanol, 1-pentanol, 2-pentanol, diacetone alcohol, and the like.

[0023] At the same time, the hydrophobic silica contained in the protective layer is high-purity silica with an average primary particle size of 5 to 50 nm, which is treated with an organosilicon compound such as organosilane or silicone oil. relative humidity of at least 80
% water absorption is preferably 1% or less. For example, silica is reacted with hexamethylene disilazane to replace the silanol groups on the silica surface with trimethylsilyl groups, and silica is reacted with a silicone compound to replace it with polydimethylsiloxane to make it hydrophobic. It will be done.

The protective layer of the electrophotographic photoreceptor of the present invention is prepared by using a coating liquid in which a hydrolyzate of these alkoxysilanes and a urethane elastomer are dissolved in a solvent that dissolves both, and hydrophobic silica is further dispersed therein. Dip coating method on photosensitive layer,
It is formed by applying it by a normal coating method such as a spin coating method, a spray coating method, an electrostatic coating method, etc., drying it, and then hardening it by heat treatment. Heat treatment temperature is 80℃~200℃
However, considering the heat resistance of the photosensitive layer, it is 80°C to 120°C.
It is preferably around ℃. The thickness of the protective layer is 0.2 to 5.
The thickness is preferably 0.5 to 2 μm in consideration of electrophotographic properties, adhesion, and abrasion resistance.

The ratio of the thermosetting silicone resin to the urethane elastomer in the protective layer is preferably from 2:8 to 8:2 in solid weight ratio after drying, and as the ratio of the silicone resin decreases, the surface hardness increases. Moreover, if the ratio of silicone resin is too large, cracks may occur due to curing shrinkage of the silicone resin during film formation, and the adhesion with the lower layer may deteriorate.

Furthermore, the amount of hydrophobic silica dispersed in the protective layer is determined based on the total solid content of the protective layer from the viewpoints of coating liquid stability, coating film strength, film formability, surface roughness, etc. 1 to 200 parts by weight, preferably 5 to 100 parts by weight per 100 parts by weight
Parts by weight range.

The surface lubricating layer of the electrophotographic photoreceptor of the present invention should be a resin film that is soluble in inert solvents such as water, alcohol solvents, and fluorine solvents in order to stack the layers without corroding the lower layer. Preferably, the resin is dissolved in a suitable solvent, coated and dried by a conventional coating method such as dip coating, spin coating, spray coating, or electrostatic coating to form a surface lubricating layer. Fluorinated copolymers that are soluble in perfluorodimethylcyclohexane or perfluorobutyltetrahydrofuran are used.

If the thickness of the surface lubricating layer is too thin, sufficient lubricity will not be obtained, and if it is too thick, the repeated stability of electrostatic properties and environmental stability will be lost, so it is preferably 0.01 μm or more and 0.5 μm. It is as follows. If the surface roughness of the protective layer is too small compared to the film thickness of the surface lubricant layer, the mechanical film life of the surface lubricant layer will be shortened, and if it is too large, sufficient surface cleanability will not be obtained. Roughness is 0.01μm
The thickness is preferably in the range of 0.5 μm or less, which is approximately the same as the thickness of the surface lubricating layer.

Examples of the electron-donating substance used in the charge transport layer of the electrophotographic photoreceptor of the present invention include compounds having an electron-donating group such as an alkyl group, an alkoxy group, an amino group, and an imide group, anthracene, pyrene, and phenanthrene. Polycyclic aromatic compounds or derivatives having a skeleton thereof, heterocyclic compounds such as indole, oxazole, oxadiazole, carbazole, thiazole, pyrazoline, imidazole, triazole, etc. or derivatives having a skeleton thereof. These electron-donating substances and binder resin are dissolved in a suitable solvent, coated and dried by a conventional coating method such as dip coating, spin coating, spray coating, or electrostatic coating to form a charge transport layer. but,
When the electron-donating substance is a polymer compound, the charge transport layer may be formed alone without mixing with a binder resin. The thickness of the charge transport layer is from several μm to several tens of μm, preferably from 5 to 25 μm.

[0030] Further, as the charge generating substance used in the charge generating layer of the electrophotographic photoreceptor of the present invention, phthalocyanine type,
Azo series, squarerium series, cyanine series, quinone series,
Examples include various pigments or dyes such as perylene-based pigments. The charge-generating layer is prepared by adding and dispersing these pigments or dyes and a suitable binder resin, and applying a coating solution prepared using a conventional coating method such as dip coating, spin coating, spray coating, or electrostatic coating. It is coated and dried by heating to form a film with a thickness of several μm, preferably 0.2 to 2 μm.

[0031] The binder resin used in the charge generation layer and the charge transport layer is used as necessary for the purpose of improving adhesion with other layers, improving the uniformity of the coating film, and adjusting fluidity during coating. , specifically polyester, polyvinyl chloride,
Polyvinyl butyral, polyvinyl acetate, polycarbonate, fluororesin, methacrylic resin, silicone resin,
Alternatively, copolymers of these resins may be mentioned. The solvent may be one that dissolves the charge generating agent, charge transporting agent, or binder resin, and specifically, halogenated hydrocarbons, aromatics, hydrocarbons, ketones, esters, ethers, etc. etc. can be used.

The conductive support used in the electrophotographic photoreceptor of the present invention may be any conventionally known conductive support, including metal plates and drums made of aluminum, aluminum alloy, tin oxide, Plates made of metal oxides such as indium oxide, or those metals and metal oxides, etc., are vacuum evaporated, sputtered, laminated,
These include various plastic films, papers, etc. that have been applied by coating and treated to be conductive.

Furthermore, the electrophotographic photoreceptor of the present invention has an adhesive layer or an adhesive layer of casein, polyvinyl alcohol, polyvinyl butyral, polyamide, etc. between the conductive support and the charge transport layer, as in the case of ordinary electrophotographic photoreceptors. A barrier layer can be provided.

In this manner, the electrophotographic photoreceptor of the present invention is formed by laminating the photosensitive layer comprising the charge transport layer and the charge generation layer, the protective layer, and the surface lubricating layer on the conductive support. A charge transport layer, a charge generation layer, a protective layer, and a surface lubricant layer are laminated in this order on a support, and are positively charged and sensitive.

Examples of the present invention will be described in detail below, but the present invention is not limited to the combinations shown in the following examples.

An electrophotographic photoreceptor according to an embodiment of the present invention will be described below. 1,1-bis(p-diethylaminophenyl)-4,4-diphenyl-1,3-butadiene
1 part by weight and 1 part by weight of polycarbonate (manufactured by Bayer AG, trade name Macrohole N) were dissolved in 9 parts by weight of methylene chloride, and this coating solution was applied by dip coating onto an aluminum drum with an outer diameter of 25 mm, and heated at 80°C for 1 hour. It was dried to form a charge transport layer with a thickness of 20 μm.

Next, 5 parts by weight of τ-type metal-free phthalocyanine (manufactured by Toyo Ink Manufacturing Co., Ltd.) and acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Dianal HR664) were added.
4 parts by weight and 1 part by weight of melamine resin (trade name: Super Beckamine L145-60, manufactured by Dainippon Ink Co., Ltd.) were dispersed in 115 parts by weight of s-butyl alcohol. This coating liquid was dip-coated onto the charge transport layer and dried at 130° C. for 1 hour to form a charge generation layer with a thickness of 0.2 μm.

In addition, 70 parts by weight of thermosetting silicone resin (manufactured by Toshiba Silicone Corporation) and urethane elastomer (trade name: OLESTAR NL2, manufactured by Mitsui Toatsu Chemical Co., Ltd.)
249E) 30 parts by weight and 100 parts by weight of n-butyl alcohol
A coating liquid was prepared by adding 50 parts by weight of hydrophobic silica (product name: Cabosil TS530, manufactured by Cabot Corporation) to the coating liquid dissolved in 0 parts by weight, and dispersing it by ultrasonic dispersion. This coating liquid was applied by dip coating onto the charge generation layer, and the coating solution was applied at 110°C for 1 hour.
It was heat-treated for a period of time and cured to form a protective layer having a film thickness of 1 μm and a surface centerline average roughness of 0.1 μm.

In addition, 1 part by weight of a fluorinated copolymer of ethylene and ethylene having an alicyclic ether group as a substituent (trade name: Teflon AF-1600, manufactured by DuPont) was added to perfluorobutyltetrahydrofuran (trade name, manufactured by 3M Company). A coating solution prepared by dissolving 100 parts by weight of Fluorinert FC-77) was applied by dip coating onto the protective layer.
It was dried by heating at ℃ for 30 minutes to form a surface lubricating layer with a thickness of 0.1 μm.

The electrophotographic photoreceptor obtained in this manner was installed in a self-made image testing machine and exposed to high temperature and high humidity (35°C, 85R).
H%) 1000 sheets, 2000 sheets, 3000 sheets, 400 sheets
The state of image bleeding was evaluated when 0, 5,000, and 6,000 sheets were printed. FIG. 1 is a block diagram of an image testing machine for an electrophotographic photoreceptor in an embodiment of the present invention.

In FIG. 1, 1 is a main charging section, 2 is a laser exposure section for writing an electrostatic latent image, 3 is a non-magnetic one-component DC flying developing section, 4 is a paper and paper transport section, 5 is a transfer section, and 6 is a transfer section. The fixing section 7 is a toner cleaning section using a urethane blade.

[0042] The evaluation results are shown in (Table 1).

[0043]

[Table 1]

As described above, according to this embodiment, an electrophotographic photoreceptor is formed by laminating a charge transport layer, a charge generation layer, a protective layer, and a surface lubricating layer in this order on a conductive support. It contains a thermosetting silicone resin, a urethane elastomer, and a hydrophobic silica, and its surface roughness is 0.01 μm or more and 0.5 μm or less in terms of center line average roughness, and the surface lubricant layer is 0.01 μm or more and 0.01 μm or more. The electrophotographic photoreceptor, which has a diameter of .5 μm or less, is positively charged and sensitive, and is stable against temperature and humidity, and is particularly effective against surface resistance under high temperature and high humidity due to surface deposits such as paper dust after repeated use. There is no image blurring due to deterioration, and even with a thin protective layer, the hardness and film strength are high.
An object of the present invention is to provide an electrophotographic photoreceptor with excellent wear resistance and durability.

A second embodiment of the present invention will be described below. In the protective layer of the first example, instead of 70 parts by weight of thermosetting silicone resin (manufactured by Toshiba Silicone Corporation) and 30 parts by weight of urethane elastomer (trade name Orestar-NL2249E, manufactured by Mitsui Toatsu Chemical Co., Ltd.) ,
A charge transport layer, a charge generation layer, a protective layer, and a surface lubricant layer were formed in the same manner as in the first example except that 50 parts by weight of thermosetting silicone resin and 50 parts by weight of urethane elastomer were used. Image evaluation was performed in the same manner as in the examples.

The evaluation results are shown in (Table 1). A third embodiment of the present invention will be described below.

In the surface lubricating layer of the first example, instead of 1 part by weight of a fluorinated copolymer of ethylene and ethylene having an alicyclic ether group as a substituent (manufactured by DuPont, trade name Teflon AF-1600) In addition, a fluorinated copolymer of ethylene and ethylene having an alicyclic ether group as a substituent (manufactured by DuPont, trade name Teflon AF-25)
00) A charge transport layer, a charge generation layer, a protective layer, and a surface lubricating layer were formed in the same manner as in the first example except that the amount was 1 part by weight, and image evaluation was performed in the same manner as in the first example. Ta.

[0048] The evaluation results are shown in (Table 1). A fourth embodiment of the present invention will be described below.

In the surface lubricating layer of the first embodiment, perfluorodimethylcyclohexane (manufactured by PCR Company, 12 parts by weight) was used instead of 100 parts by weight of perfluorobutyltetrahydrofuran (trade name Fluorinert FC-77, manufactured by 3M Company).
120-2) A charge transport layer, a charge generation layer, a protective layer, and a surface lubricant layer were formed in the same manner as in the first example except that the amount was 100 parts by weight, and image evaluation was performed in the same manner as in the first example. I did this.

The evaluation results are shown in (Table 1). In addition, as a comparative example of the present invention, a thermosetting silicone resin and a urethane elastomer (manufactured by Mitsui Toatsu Chemical Co., Ltd.) were used as a protective layer.
Product name: OLESTAR NL2249E) and hydrophobic silica (
Manufactured by Nippon Aerosil Co., Ltd. Product name Aerosil R97
4) was used to create a sample with a configuration in which no surface lubricant layer was provided.

In the protective layer of the first embodiment, hydrophobic silica (manufactured by Cabot Corporation, trade name: CABOSIL TS530) was used.
) A charge transport layer, a charge generation layer, and a protective layer were prepared in the same manner as in the first example except that 30 parts by weight of hydrophobic silica (trade name Aerosil R974, manufactured by Nippon Aerosil Co., Ltd.) was used instead of 50 parts by weight. The image was evaluated in the same manner as in the first example.

[0052] The evaluation results are shown in (Table 1).

[0053]

As described above, the present invention provides an electrophotographic photoreceptor with a charge transport layer, a charge generation layer, a protective layer, a charge transport layer, a charge generation layer, a protective layer, etc.
It is formed by laminating a surface lubricating layer in this order, and the protective layer contains a thermosetting silicone resin, a urethane elastomer, and a hydrophobic silica, and its surface roughness is 0.0 in center line average roughness.
Due to the electrophotographic photoreceptor having a diameter of 1 μm or more and 0.5 μm or less, and a surface lubricating layer of 0.01 μm or more and 0.5 μm or less, it is positively charged and sensitive, and is stable against temperature and humidity, especially after repeated use. There is no image blurring due to a decrease in surface resistance due to surface deposits such as paper dust under high temperature and high humidity conditions, and even with a thin protective layer, the hardness and film strength are high, and the film has excellent abrasion resistance.
An electrophotographic photoreceptor with excellent durability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an image testing machine for an electrophotographic photoreceptor in a first embodiment of the present invention.

[Explanation of symbols]

1 Main charging section 2 Laser exposure section for electrostatic latent image writing 3 Non-magnetic one-component DC flying development section 4 Paper and paper transport section 5 Transfer section 6 Fixing section

Claims (3)

[Claims] 1. An electrophotographic photosensitive member formed by laminating a photosensitive layer, a protective layer for the photosensitive layer, and a surface lubricating layer on a conductive support, wherein the protective layer is made of a thermosetting silicone resin and a urethane elastomer. Furthermore, it contains hydrophobic silica, the surface roughness of which is 0.01 μm or more and 0.5 μm or less in center line average roughness, and the surface lubricant layer has a center line average roughness of 0.01 μm or more and 0.5 μm or less.
An electrophotographic photoreceptor characterized in that the diameter is 0.5 μm or more. 2. The electrophotographic photoreceptor according to claim 1, wherein the surface lubricating layer is a fluorinated copolymer. 3. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer is formed by laminating a charge transport layer and a charge generation layer in this order on a conductive support.