JPH1090932A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor excellent in cleaning property by reducing the frictional coefficient of a surface layer is reduced, resistant to wear and flaw, and causes no rise of residual potential in electrophotographic process even by repeated use by containing a cross-linked type polystyrene resin particle in the surface layer of the photoreceptor. SOLUTION: A cross-linked type polystyrene resin particle is contained in the surface layer of a photoreceptor. According to this structure, the dispersed polystyrene resin particle is partially exposed to the photoreceptor surface, irregularities are formed by the polystyrene particle, whereby the contact area with a contact member can be reduced in development by toner, image transfer and cleaning. In a general manufacturing process of photoreceptor, the used cross-linked type polystyrene is generally dispersed with a solvent, or mixed with a proper binder resin or with a charge moving material as occasion demands after dispersion, or preliminarily dispersed with the binder resin or with a charge moving material as occasion demands.

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 used in a copying machine, a printer, and the like using an electrophotographic process, and more particularly, to an electrophotographic photosensitive member excellent in durability with less deterioration in image quality due to repeated use. About.

[0002]

2. Description of the Related Art In the field of photoconductive materials for electrophotographic photoreceptors, various organic photoconductive materials have been developed in recent years. In particular, a function-separated type photoreceptor in which a charge generation layer and a charge transport layer are laminated has already been put to practical use. , Mounted on copiers and printers. The electrophotographic photoreceptor must have sensitivity, electrical characteristics and optical characteristics according to the electrophotographic process to be applied. Since electrical and mechanical external forces are directly applied by processes such as development, transfer to paper, and cleaning, durability against these is required. Specifically, durability against abrasion of the surface due to friction, generation of scratches, and the like is required. Further, there is a problem that toner is adhered to the surface layer due to repetition of development and cleaning with toner. To solve this problem, improvement of the cleaning property of the surface layer is required.

As described above, various methods have been studied to satisfy the characteristics required for the surface layer. For example, JP-A-6-332219 and JP-A-6-23059.
No. 1 describes that the dispersion of fluorine resin particles reduces the friction coefficient of the surface layer to improve the cleaning property, and also improves the durability against abrasion and scratches. However, fluorine resin particles have a problem in dispersibility, it is difficult to form a uniform and smooth film, and image defects such as image unevenness and pinholes cannot be avoided. Further, when these fluorine-based resin particles are used, the electrophotographic characteristics are deteriorated, and particularly, the residual potential is increased by repeated use, which causes image fogging.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member which meets the above-mentioned requirements.
That is, an object of the present invention is to reduce the coefficient of friction of the surface layer, to have excellent cleaning properties and durability against abrasion and scratches, and not to increase the residual potential in a repetitive use electrophotographic process, so that high quality is always achieved. An object of the present invention is to provide an electrophotographic photoreceptor capable of obtaining the image of

[0005]

According to the present invention, first, in an electrophotographic photosensitive member having a photosensitive layer provided directly or via an undercoat layer on a conductive support, a surface layer of the photosensitive member is provided. An electrophotographic photoreceptor characterized by containing one or more crosslinked polystyrene resin particles is provided. Secondly, there is provided the electrophotographic photosensitive member according to the first aspect, wherein the surface layer of the photosensitive member is a photosensitive layer or a protective layer provided on the photosensitive layer. Thirdly, there is provided the electrophotographic photosensitive member according to the second aspect, wherein the charge transport material is contained not only in the photosensitive layer but also in the protective layer. Fourthly, in the electrophotographic photoreceptor described in the first, second or third aspect, the photosensitive layer comprises a charge generation layer containing a charge generation material and a charge transport layer containing a hole transport material. Is provided. Fifth, the electrophotographic photoreceptor according to the first, second or third aspect, wherein the photosensitive layer comprises a charge generating layer containing a charge generating substance and a charge transporting layer containing an electron transporting substance. To provide a positively charged electrophotographic photosensitive member. Sixth, an electrophotographic photoreceptor according to the first, second or third aspect, wherein the photosensitive layer is a single layer containing a charge generating substance and a charge transport material. Is done.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As described above, the electrophotographic photoreceptor of the present invention contains crosslinked polystyrene resin particles in the surface layer of the photoreceptor. According to this configuration, the dispersed polystyrene resin particles are partially exposed on the surface of the photoreceptor. However, irregularities are formed by the polystyrene resin particles, so that the area of contact with the contact member can be reduced during development, image transfer, and cleaning with the toner, and the above-described problem can be solved.

The cross-linked polystyrene resin particles used in the present invention are dispersed together with a solvent in a usual electrophotographic photoreceptor manufacturing process, or after dispersion with an appropriate binder resin or, if necessary, with a charge transfer material. In general, they are mixed or dispersed in advance with a binder resin or, if necessary, with a charge transfer material. Examples of such a binder resin include bisphenol A-type polycarbonate resin, bisphenol Z-type polycarbonate resin, other polycarbonate resins, acrylic resin, methacrylate resin, polyethylene resin, styrene resin, acryl-styrene copolymer resin, polyester resin, and polyurethane resin. A resin or the like may be used alone or a plurality of resins may be used.

The surface layer can also contain a dispersing aid or a surfactant for dispersing the crosslinked polystyrene resin particles, as well as a sensitizer and an antioxidant. The photoreceptor of the present invention needs to contain cross-linked polystyrene resin particles in an effective amount in a surface layer thereof in an effective amount without aggregation, and the content of the dispersed cross-linked polystyrene resin is solid. The appropriate amount is 0.01% by weight to 50% by weight, but particularly preferably 1% by weight to 20% by weight. When the content is less than 0.01% by weight, there is no sufficient effect to solve the above-mentioned problems, and when the content is more than 50% by weight, the electrophotographic characteristics are deteriorated. For dispersion of the crosslinked polystyrene resin particles, a dispersion method such as a homogenizer, a ball mill, a sand mill, an attritor, a roll mill, and an ultrasonic dispersion can be used. As a coating method, an immersion method, a spray method, a roll coating method, or the like can be used.

In the present invention, it is effective to apply the surface layer containing the crosslinked polystyrene resin particles to a layer which is in direct contact with a toner, a developing device, a cleaning device or the like. The photoreceptor has a layer structure in which a cross-linked polystyrene resin particle contains a charge generating substance and a charge transporting material in a single photosensitive layer. The charge-transporting layer is provided in a charge-transporting layer for a function-separated photoreceptor having a charge-transporting layer containing a charge-transporting material on the layer, and the protective layer is provided in a photoreceptor having a protective layer provided on the photosensitive layer. In the case of the above-mentioned laminated type, the charge transport layer contains a hole transport material to form a negatively charged photoreceptor, and the charge transport layer contains an electron transport material to form a positively charged photoreceptor. It is possible. The protective layer may contain a charge transport material in the photosensitive layer and further contain the same to improve electrophotographic properties.

In producing the electrophotographic photoreceptor of the present invention,
As the conductive support, aluminum, nickel, copper,
Metal plates such as titanium and gold, metal drums or metal foils, plastic films deposited with aluminum, nickel, copper, titanium, tin oxide, indium oxide, etc. or paper or plastic films or drums coated with conductive materials Can be used.

An undercoat layer having a barrier function and an adhesive function can be provided on the conductive support. Polyamide resin, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose,
Resins such as vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, casein, N-alkoxymethyl nylon, or tin oxide, aluminum oxide, titanium oxide, silicon oxide, or oxidized resin A material in which indium or the like is dispersed or a deposited film of aluminum oxide, zinc oxide, titanium oxide, silicon oxide, or the like can be used as the undercoat layer. The thickness is in the range of 0.1 to 2 μm.

The charge generating substance used in the present invention includes:
If it absorbs visible light and generates free charge,
Both inorganic and organic substances can be used. For example, amorphous selenium, trigonal selenium, selenium-
Inorganic substances such as arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium sulfate selenide, amorphous silicon, or bisazo dyes, polyazo dyes, triarylmethane dyes, thiazine dyes, oxazine dyes, Xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone dyes, indigo dyes, perylene dyes, polycyclic quinone dyes, bisbenzimidazole dyes, indanthrone dyes, squarium dyes, Organic substances such as anthraquinone-based dyes and phthalocyanine-based dyes such as X-type metal-free phthalocyanine and titanyl phthalocyanine are exemplified.

When the charge generation material is dispersed to form a charge generation layer, the charge generation material is preferably a powder having an average particle size of 2 μm or less, preferably 1 μm or less. That is, if the particle size is too large, the dispersion in the layer becomes worse, and the particles partially protrude from the surface to deteriorate the surface smoothness, and in some cases, discharge occurs at the protruding portion of the particles, or toner particles are there. Adhesion tends to cause a toner filming phenomenon. On the other hand, if the particle size is too small, it tends to agglomerate rather, increasing the resistance of the layer, decreasing the sensitivity and repetition characteristics due to an increase in crystal defects, or limiting the miniaturization. Is preferably 0.01 μm.

The charge generation layer can be provided by the following method. That is, the charge generating substance is made into fine particles in a dispersion medium by a ball mill, a homomixer, or the like,
This is a method of applying a dispersion obtained by adding a binder resin and mixing and dispersing as necessary. In this method, when the particles are dispersed under the action of ultrasonic waves, uniform dispersion is possible. In the charge generation layer, the ratio of the charge generation material contained in the binder resin is 20 to 200 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer formed as described above is preferably 0.1 to 10 μm, particularly preferably 0.2 to 2 μm.

As the charge transporting material (hole transporting material), a conventionally known hole transporting material can be used. For example, a compound having a triphenylamine moiety, a compound having a carbazole moiety, a hydrazone compound, Donor compounds such as a triphenylmethane compound, an oxazole compound, a styryl compound, a butadiene compound, a polysilane compound, polyvinylcarbazole, and a pyrene-formalin condensate are exemplified.

As the charge transport material (electron transport material),
Conventionally known electron transporting substances can be used, and examples thereof include fluorene-based compounds such as trinitrofluorenone and fluorenylidenemethane derivatives, and quinone-based compounds such as diphenoquinone and anthraquinone derivatives.

The charge transporting layer can be provided by dissolving or dispersing the charge transporting material in an appropriate solvent together with a binder resin, if necessary, coating and drying. The ratio of the charge transporting material to the binder resin in the charge transporting layer is preferably 0 to 400 parts by weight, particularly 50 to 200 parts by weight, based on 100 parts by weight of the charge transporting material. The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 10 to 30 μm. The thickness of the charge transport layer is 5 to
50 μm, especially 10 to 30 μm is desirable.

Examples of the solvent used for preparing a dispersion or solution of the charge generation layer or the charge transport layer include N, N-dimethylformamide, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, and the like.
1,1,1-trichloroethane, dichloromethane, 1,
Examples thereof include 1,2-trichloroethane, trichloroethylene, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, and butyl acetate.

Examples of the binder resin used for the charge generation layer or the charge transport layer include polyethylene, polyvinyl butyral, polyvinyl formal, polystyrene resin, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, and epoxy resin. Resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, polyamide resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin, polycondensation type resin, and repeating units of these resins Copolymer resins containing two or more of them, for example, vinyl chloride-vinyl acetate copolymer, styrene-acrylic copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and other insulating resins, −
A high-molecular organic semiconductor such as N-vinylcarbazole may be used.

In the present invention, when a protective layer is provided as a surface layer of a photoreceptor, a coating solution in which at least crosslinked polystyrene resin particles are dispersed in a binder resin is prepared.
It is formed by coating and drying on the photosensitive layer. As described above, the charge transport material may be dispersed not only in the photosensitive layer but also in the protective layer in the protective layer.

[0021]

The present invention will be described in more detail with reference to the following examples.

Example 1 5 parts of a charge generating material represented by the following formula (P-1), 2.5 parts of butyral resin (XYHL, manufactured by Union Carbide Co.) and 92.5 parts of tetrahydrofuran were subjected to ball milling. The mixture was dispersed for 12 hours, and then tetrahydrofuran was added to a concentration of 2% by weight of the dispersion, followed by redispersion to prepare a coating solution. The prepared dispersion was applied by casting with a doctor blade onto an aluminum plate (0.1 mm thick) to form a charge generation layer having a thickness of 0.3 μm after drying.

Embedded image Next, on the charge generation layer thus obtained, 8 parts of a charge transport material (D-1) having the following structural formula, 10 parts of polycarbonate Z (manufactured by Teijin Chemicals Limited), and methylphenyl silicon (KF50-100 cps: Shin-Etsu Chemical Co., Ltd.) 0.002
Parts were dissolved in 90 parts of tetrahydrofuran. Further, a liquid in which 0.2 part of cross-linked polystyrene resin particles (SX8742-03, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 4 parts of tetrahydrofuran are dispersed by vibration mill dispersion is added to the above-described solution, and ultrasonically dispersed to prepare a coating liquid. did. The obtained coating solution is cast and coated on the above-mentioned charge generation layer by a doctor blade to form a charge transport layer having a thickness of 18 μm after drying, and is composed of a conductive support / charge generation layer / charge transport layer. The electrophotographic photoreceptor to be manufactured was produced.

Embedded image

Example 2 Aluminum plate (0.1 mm)
Thickness), an undercoating layer made of a polyamide resin (CM8000, manufactured by Toray Industries, Inc.) having a thickness of 0.3 μm was provided thereon, and a charge generation layer and a charge transport layer similar to those in Example 1 were sequentially provided thereon. An electrophotographic photoreceptor composed of / undercoat layer / charge generation layer / charge transport layer was prepared.

Example 3 Charge transport material (D-1) 10
Parts, 10 parts of polycarbonate Z (manufactured by Teijin Chemicals Ltd.) and 0.002 parts of methylphenyl silicon (KF50-100 cps: manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved in 100 parts of tetrahydrofuran, and a doctor blade was placed on the charge generation layer of Example 2. And dried to form a charge transport layer having a thickness of 15 μm. Next, 5 parts of polycarbonate Z (manufactured by Teijin Chemicals Ltd.) are dissolved in 70 parts of tetrahydrofuran, and 0.05 parts of crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 25 parts of tetrahydrofuran
Part was dispersed in a vibration mill, the dispersion liquid was added to the above-described solution, and the mixture was ultrasonically dispersed to prepare a coating liquid. The coating liquid was cast-coated on the above-described charge transport layer with a doctor blade, and dried. Then, a protective layer having a thickness of 4 μm was provided to prepare an electrophotographic photosensitive member composed of a conductive support / subbing layer / charge generation layer / charge transport layer / protective layer.

Example 4 A protective layer was provided in the same manner as in Example 3 except that 0.1 part of crosslinked polystyrene resin particles was used, and a conductive support / undercoat layer / charge generation layer / charge transport layer was used. / An electrophotographic photosensitive member composed of a protective layer was prepared.

[Example 5] In Example 3, 5 parts of polycarbonate Z (manufactured by Teijin Chemicals Ltd.)
Was dissolved in 70 parts of tetrahydrofuran, and a dispersion of 0.05 part of cross-linked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 25 parts of tetrahydrofuran was dispersed in a vibration mill. In addition to the above solution, an ultrasonic dispersion was applied to prepare a coating solution, and the solution was cast-coated on the above-described charge transport layer with a doctor blade, and dried to provide a protective layer having a thickness of 4 μm. A protective layer was provided in the same manner as in Example 3, to prepare an electrophotographic photosensitive member composed of a conductive support / subbing layer / charge generation layer / charge transport layer / protective layer.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that no crosslinked polystyrene resin particles (SX8742-03, manufactured by Nippon Synthetic Rubber Co., Ltd.) were used.

With respect to the obtained electrophotographic photosensitive member, the change in residual potential, the coefficient of friction, and the amount of film shaving on the photosensitive member surface were measured by the following measuring methods. Table 1 shows the results. <Change in Residual Potential> The process of charging (negative charging), exposing, and removing light from an electrophotographic photosensitive member using an electrostatic copying paper tester (EPA-8200, manufactured by Kawaguchi Electric Works) is repeated 5000 times in a 5-second cycle. The change in residual potential was measured. <Measurement of Coefficient of Friction> Using a DFPM-SS manufactured by Kyowa Interface Science Co., Ltd., the load was measured at 50 g and point contact with a stainless steel ball. <Film shaving amount on photoreceptor surface> Taper test (CS-10)
The results were shown by

[0029]

[Table 1]

From Table 1, it can be seen that the example of the present invention has a smaller increase in residual potential after the endurance than the comparative example, and that the coefficient of friction is small and the shaving amount is clearly small.

[Embodiment 6] On an aluminum cylinder,
0.1 made of polyamide resin (CM8000 manufactured by Toray Industries, Inc.)
An undercoat layer having a thickness of 5 μm is provided, and the charge generation material (P-1) 5
Part, butyral resin (Denka butyral resin # 3000)
-2: manufactured by Denki Kagaku Kogyo Co., Ltd.) 2.5 parts and 92.5 parts of tetrahydrofuran were dispersed in a ball mill for 12 hours,
Next, tetrahydrofuran was added to a concentration of 2% by weight of the dispersion and redispersed to prepare a coating liquid. The prepared dispersion was dip-coated on the undercoat layer to form a charge generation layer having a thickness of 0.3 μm after drying. Next, 10 parts of charge transport material (D-1), 10 parts of polycarbonate Z (manufactured by Teijin Chemicals Limited), and methylphenyl silicon (KF50-10)
0.002 parts (0 cps: Shin-Etsu Chemical Co., Ltd.) was dissolved in 100 parts of tetrahydrofuran, dip-coated on the charge generation layer of Example 2, and dried to form a charge transport layer having a thickness of 15 μm. Next, 5 parts of polycarbonate Z (manufactured by Teijin Chemicals) were dissolved in 70 parts of toluene, and crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) were added thereto.
A dispersion obtained by dispersing a dispersion consisting of 0.05 part and 25 parts of toluene in a vibration mill was added to the above-described solution, ultrasonically dispersed to prepare a coating solution, and spray-coated on the above-described charge transport layer, After drying, a protective layer having a thickness of 4 μm was provided to prepare an electrophotographic photosensitive member composed of a conductive support (undercoat layer) / charge generating layer / charge transport layer / protective layer.

Comparative Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 6, except that no crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) were used.

Each of the electrophotographic photosensitive members of Example 6 and Comparative Example 2 was attached to a copying machine in which charging, exposure, development, transfer and cleaning were repeated, and copying was performed 5000 times continuously. As a result, in the electrophotographic photoreceptor of Example 6, a good image was obtained at the 5,000th time, but with the electrophotographic photoreceptor of Comparative Example 2, the sensitivity was insufficient, fog, and toner Adhesion and scratches on the photoreceptor drum caused no good image to be obtained.

Example 7 X-type metal-free phthalocyanine 5
Part, polyvinyl butyral resin (ESLEX BLS:
5 parts of Sekisui Chemical Co., Ltd.) and 90 parts of tetrahydrofuran were dispersed in a ball mill for 12 hours, and then tetrahydrofuran was added to a concentration of 2% by weight of the dispersion and redispersed to prepare a coating liquid. The coating solution thus prepared was cast and applied on an aluminum plate (0.1 mm) by a doctor blade to form a charge generation layer having a dried film thickness of 0.4 μm. Next, a charge transport material (A-
1) 7 parts, polycarbonate Z (manufactured by Teijin Chemicals Ltd.) 10
Part, methyl phenyl silicon (KF50-100cp
(s: manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in 90 parts of tetrahydrofuran. Further, crosslinked polystyrene resin particles (SX8742-03, manufactured by Nippon Synthetic Rubber Co., Ltd.) 0.2
Part, 4 parts of tetrahydrofuran and a liquid dispersed by vibration mill dispersion were added to the above-mentioned solution, and the mixture was ultrasonically dispersed to prepare a coating solution. A charge transport layer having a thickness of 18 μm was formed, and an electrophotographic photosensitive member composed of a conductive support / charge generation layer / charge transport layer was produced.

[0035]

Embedded image

Example 8 An aluminum plate (0.1 mm
Thickness), a 0.5 μm thick undercoat layer made of a polyamide resin (CM8000, manufactured by Toray Industries, Inc.) was provided thereon.
A charge generation layer and then a charge transport layer were provided in the same manner as in Example 1 to prepare an electrophotographic photosensitive member composed of a conductive support / undercoat layer / charge generation layer / charge transport layer.

Example 9 Charge transport material (A-1) 7
Parts, 10 parts of polycarbonate Z (manufactured by Teijin Chemicals Ltd.) and 0.002 parts of methylphenyl silicon (KF50-100 cps: manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved in 100 parts of tetrahydrofuran, and a doctor blade was placed on the charge generation layer of Example 2. And dried to form a charge transport layer having a thickness of 15 μm. Next, polycarbonate Z (manufactured by Teijin Chemicals)
5 parts were dissolved in 70 parts of tetrahydrofuran, and a dispersion obtained by dispersing a dispersion composed of 0.05 parts of crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 25 parts of tetrahydrofuran in a vibration mill was added thereto. In addition to the solution described above, a coating solution was prepared by ultrasonic dispersion, cast and coated on the charge transport layer with a doctor blade, and dried to provide a protective layer having a thickness of 4 μm. An electrophotographic photoreceptor composed of / undercoat layer / charge generation layer / charge transport layer / protective layer was prepared.

Example 10 A protective layer was provided in the same manner as in Example 9 except that 0.1 part of crosslinked polystyrene resin particles was used, and a conductive support / subbing layer / charge generation layer / charge transport was used. An electrophotographic photosensitive member composed of a layer and a protective layer was prepared.

[Example 11] In Example 9, 5 parts of polycarbonate Z (manufactured by Teijin Chemicals Ltd.)
Was dissolved in 70 parts of tetrahydrofuran, and a dispersion of 0.05 part of cross-linked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 25 parts of tetrahydrofuran was dispersed in a vibration mill. In addition to the above solution, the dispersion was subjected to ultrasonic dispersion to prepare a coating solution, cast and coated on the above-described charge transport layer with a doctor blade, and dried to provide a protective layer having a thickness of 4 μm. Similarly, a protective layer is provided, and the conductive support / subbing layer / charge generation layer /
An electronic photoreceptor composed of a charge transport layer / protective layer was prepared.

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that no crosslinked polystyrene resin particles (SX8742-03, manufactured by Nippon Synthetic Rubber Co., Ltd.) were used.

Example 12 1 part of X-type metal-free phthalocyanine, 18 parts of the charge transport material (D-1), 6 parts of the charge transport material (A-1), 10% by weight of polycarbonate Z (manufactured by Teijin Chemicals Ltd.) ) 250 parts of a tetrahydrofuran solution and 50 parts of tetrahydrofuran were dispersed in a ball mill for 6 hours to prepare a coating solution. The coating solution thus prepared was cast and applied on an aluminum plate (0.1 mm) with a doctor blade, and the film thickness after drying was 15 μm (single-layer type).
A photosensitive layer was formed. Next, 5 parts of Polycarbonate Z (manufactured by Teijin Chemicals Ltd.) was dissolved in 70 parts of tetrahydrofuran, and crosslinked polystyrene resin particles (SX8742-05,
0.05 parts of Nippon Synthetic Rubber Co., Ltd. and tetrahydrofuran 2
The dispersion obtained by dispersing the dispersion consisting of 5 parts by a vibration mill is added to the above-mentioned solution, and the mixture is ultrasonically dispersed to prepare a coating solution, which is cast on the (single-layer type) photosensitive layer by a doctor blade. Coating and drying were performed to provide a protective layer having a thickness of 4 μm to prepare an electrophotographic photosensitive member composed of a conductive support / single-layer type photosensitive layer / protective layer.

Comparative Example 4 An electrophotographic photosensitive member was produced in the same manner as in Example 12, except that no crosslinked polystyrene resin particles (SX8742-03, manufactured by Nippon Synthetic Rubber Co., Ltd.) were used.

With respect to the electrophotographic photosensitive members of Examples 7 to 11 and Comparative Examples 3 and 12 and Comparative Examples 4 obtained above, the change in residual potential, the coefficient of friction, and the amount of film shaving on the photosensitive member surface were determined by the following methods. Was measured by Table 2 shows the results. <Change in residual potential> Electrostatic copying paper tester (EPA-82
00: manufactured by Kawaguchi Electric Works, Ltd., the process of charging (positive charging), exposure, and light elimination was repeated 5000 times in a 5-second cycle, and the change in residual potential was measured. <Coefficient of friction> Using DFPM-SS manufactured by Kyowa Interface Science,
Load: 50 g, measured by point contact with a stainless steel ball. <Film shaving amount on photoreceptor surface> The film shaving amount on the photoreceptor surface shows the result of a taper test (CS-10).

[0044]

[Table 2]

Example 13 A 0.5 μm thick undercoat layer made of a polyamide resin (CM8000 manufactured by Toray Industries, Inc.) was provided on an aluminum cylinder, and 5 parts of an X-type non-metallic phthalocyanine, butyral resin (denka butyral resin # 3)
000-2, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 5 parts of tetrahydrofuran were dispersed in a ball mill for 12 hours, and then tetrahydrofuran was added to a concentration of 2% by weight of the dispersion and redispersed to prepare a coating liquid. did. The resulting dispersion was applied onto the undercoat layer by dip coating to form a charge generation layer having a thickness of 0.3 μm after drying. Next, 10 parts of the charge transport material (D-1), 10 parts of polycarbonate Z (manufactured by Teijin Chemicals), and methylphenyl silicon (KF50-10)
0 cps: manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts was dissolved in 100 parts of tetrahydrofuran, and on the charge generation layer of Example 2,
Dip coating and drying were performed to form a charge transport layer having a thickness of 15 μm. Next, polycarbonate Z (manufactured by Teijin Chemicals Limited)
5 parts were dissolved in 70 parts of toluene, and a dispersion of 0.05 part of crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) and 25 parts of toluene was dispersed in a vibration mill. In addition to the solution described above, a coating solution is prepared by ultrasonic dispersion, spray-coated on the charge transport layer and dried to provide a protective layer having a thickness of 4 μm, and a conductive support (undercoat layer) A lightning photographic photoreceptor composed of / charge generation layer / charge transport layer / protective layer was prepared.

Comparative Example 5 An electrophotographic photosensitive member was prepared in the same manner as in Example 13, except that no crosslinked polystyrene resin particles (SX8742-05, manufactured by Nippon Synthetic Rubber Co., Ltd.) were used. This electrophotographic photosensitive member is charged, exposed,
The apparatus was mounted on a copying machine in which development, transfer, and cleaning were repeated, and copying was performed 5000 times continuously. As a result, in the electrophotographic photosensitive member of Example 6, at the 5000th time,
Although a good image was obtained, the electrophotographic photoreceptor of Comparative Example 5 was not able to obtain a good image because of insufficient sensitivity, fog, toner adhesion, and scratches on the photoreceptor drum on the 5000th sheet. Was.

[0047]

As described above, according to the electrophotographic photoreceptor of the present invention in which crosslinked polystyrene resin particles are contained in the surface layer of the photoreceptor, the friction coefficient of the surface layer is reduced, and the photoreceptor is resistant to abrasion and scratches. It is durable and can form a high quality image with little increase in residual potential in an electrophotographic process by repeated use.

Claims (6)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer provided directly or via an undercoat layer on a conductive support, wherein one or more crosslinked polystyrene resin particles are contained in a surface layer of the photosensitive member. An electrophotographic photoreceptor, comprising: 2. The electrophotographic photosensitive member according to claim 1, wherein the surface layer of the photosensitive member is a photosensitive layer or a protective layer provided on the photosensitive layer. 3. The electrophotographic photosensitive member according to claim 2, wherein the charge transport material is contained not only in the photosensitive layer but also in the protective layer. 4. An electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises a charge generating layer containing a charge generating substance and a charge transporting layer containing a hole transporting substance. Chargeable electrophotographic photoreceptor. 5. The positively charged electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises a charge generating layer containing a charge generating substance and a charge transporting layer containing an electron transporting substance. Type electrophotographic photoreceptor. 6. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is a single layer containing a charge generating substance and a charge transporting material.