JPH06236061A - Electrophotoreceptor - Google Patents

Abstract

PURPOSE:To provide an electrophotoreceptor capable of suppressing the generation of interference fringes in the case of using an electrophotographic device using coherent light. CONSTITUTION:The electrophotoreceptor is made by successively laminating an under layer 2, a charge generating layer 3 and a charge transfer layer 4 on a conductive substrate 1. The under layer 2 contains a white pigment 21 and has >=10% void 22 by volume percentage. The under layer 2 contains <=25% binder. A titanium oxide particulates 0.01-1mum in particle diameter is used as the white pigment. At least one of a polyvinyl butylal resin, an organic zirconium compound and a silane coupling agent is used as the binder.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a laminated electrophotographic photoreceptor having an improved undercoat layer on a conductive substrate.

[0002]

2. Description of the Related Art Electrophotographic devices are used in the fields of copiers, laser beam printers, etc., because of their high speed and high printing quality. As a photoconductor used in an electrophotographic apparatus, an organic photoconductor (OPC) using an organic photoconductive material has been developed and gradually spread. The photosensitive member is also composed of a single layer type photosensitive member in which a charge transfer complex structure or a charge generating material is dispersed in a binder resin, and a function separation type photosensitive member structure in which a charge generating layer and a charge transport layer are separated. The performance has improved as well. In this function-separated type photoreceptor, at present, on an aluminum pipe,
The mainstream is a structure in which an undercoat layer is first formed, and then a charge generation layer and a charge transport layer are formed.

With the progress of electrophotographic apparatuses, there is an increasing demand for long life and high quality image quality of photoconductors. Among these, in high-resolution printers and color copying machines, the digital recording method using a laser as an exposure light source is predominant, but when coherent light such as a laser is used, The light causes an interference phenomenon, and the exposure amount varies depending on the location according to the film thickness distribution of the charge transport layer, which causes a problem that a print-like interference pattern is generated on the print.

In order to solve this problem, various studies have been made such as roughening the substrate and mixing light-scattering powder in the photosensitive layer. With respect to the undercoat layer provided between the photosensitive layer and the substrate, it has been attempted to reduce interference fringes by mixing a white pigment with the resin of the undercoat layer (for example, JP-A-2-181158). Gazette, Japanese Patent Laid-Open No. Hei 3
No. 146958, Japanese Unexamined Patent Publication No. 4-191861). FIG. 2 shows these cases, in which an undercoat layer 2 composed of a white pigment 21 and a resin 23 is formed on a conductive substrate 1, and a charge generation layer 3 and a charge transport layer 4 are formed on the undercoat layer 2. It is provided.

[0005]

However, in these cases, it is not always possible to obtain a sufficient effect of preventing interference fringes.
In reality, it is used together with the roughening of the substrate. The present invention has been made for the purpose of solving the above-mentioned problems in the conventional technique. Therefore, an object of the present invention is to provide an electrophotographic photosensitive member which can prevent the occurrence of interference fringe patterns when coherent light such as a laser is used.

[0006]

Means for Solving the Problems The present inventors have completed the present invention as a result of studying a technique for preventing interference fringes by mixing a white pigment in an undercoat layer. The present invention provides an electrophotographic photosensitive member comprising an electrically conductive substrate, on which an undercoat layer, a charge generation layer and a charge transport layer are sequentially laminated, wherein the undercoat layer contains a white pigment and has a volume fraction of 10%.
It is characterized by having the above voids.

The present invention will be described in detail below. FIG. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member of the present invention, in which an undercoat layer 2 is formed on a conductive substrate 1, on which a charge generation layer 3 and a charge transport layer 4 are sequentially laminated. Has been done. The undercoat layer contains a white pigment 21, and voids 22 are formed between particles of the white pigment.

In the photoreceptor of the present invention, as the conductive support, in addition to metals such as copper, aluminum, nickel and iron, a metal is vapor-deposited on the surface or a coating film in which conductive powder is dispersed is formed. A cylindrical, belt-shaped or sheet-shaped substrate made of a conductive material such as plastic or paper can be used.

An undercoat layer containing a white pigment is formed on the surface of the conductive substrate. Examples of the white pigment include titanium oxide, zinc oxide, tin oxide, zirconium oxide, aluminum oxide, silica, magnesium oxide and the like.
If the resistance of these white pigments is too low, charge injection from the substrate is promoted, causing image quality defects, so the resistance of the white pigments is preferably in the range of 10 ⁴ to 10 ¹¹ Ω · cm. These white pigments may be surface-treated in order to adjust the resistance within the above range or to improve the dispersibility. For example, in the case of titanium oxide, fine powder of silica, alumina, zirconia or the like is used as the surface coating agent. Also, the crystal type of the white pigment can be arbitrarily selected. For example, in the case of titanium oxide, both anatase type and rutile type are known, but both can be used.

The particle size of the white pigment is preferably in the range of 0.01 to 1 μm. When the particle size is too large, the unevenness of the undercoat layer becomes remarkable and the electrical nonuniformity becomes large, so that image quality defects are likely to occur. Further, if the particle size is too small, agglomeration tends to occur and the dispersion tends to become unstable. Therefore, the above range is preferable.

In the present invention, the undercoat layer has a volume fraction of 1
It is necessary to have 0% or more voids, and the preferable range is 10% to 30%. When the volume fraction of voids is lower than 10%, an interference fringe pattern is generated.
In the subbing layer, a binder is used in addition to the above white pigment, and the binder may be in a minimum amount necessary for holding the white pigments together. The amount of the binder in the undercoat layer is 25% or less, preferably 25 to 10%, in terms of volume fraction with respect to the white pigment. Thereby, the volume fraction of voids in the undercoat layer can be made 10% or more. If the amount of the binder is too small and the number of voids is too large, the photosensitive layer coating liquid such as the charge generating layer coated thereon penetrates, and the uniformity of the photosensitive layer is impaired.
It is desirable that the amount of the binder is such that the white pigment contacts are sufficiently blocked.

The light scattering property depends on the difference in the refractive index between the white pigment and the medium surrounding it, and when the white pigment is embedded in the resin medium, the refractive index between the white pigment and the medium is large. Difference is small, and the light scattering property is small. In the undercoat layer of the present invention, since the amount of the binder is small, the contacts between the white pigments are bonded by the binder, but the gaps between the other white pigments are occupied by air. Therefore, the undercoat layer of the present invention exhibits high light scattering properties.

In the present invention, the binder used in the undercoat layer is an acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin,
Polymer resin compounds such as polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin , Silane coupling agents and organometallic compounds are mainly used. These may be used alone or in combination of two or more. Among these, silane coupling agents and organozirconium compounds have extremely high film-forming properties, low residual potential, little change due to environment, and little change in potential due to repeated use. As excellent.

As the silane coupling agent, for example,
Vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β-
(3,4-Epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (amino Ethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)
-Γ-aminopropylmethylmethoxysilane, N, N-
Examples include bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane and γ-chloropropyltrimethoxysilane. Among these silane compounds, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), and 3 are particularly preferably used.
-Methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4
-Epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane , N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane and the like.

As the organometallic compound, zirconium,
A material containing titanium, aluminum, manganese, etc. is used. Examples of the organic zirconium compound include zirconium butyrate, zirconium acetylacetonate, acetylacetone zirconium butyrate, zirconium lactate, zirconium stearate, and the like. Other organic titanium compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt. , Titanium lactate, titanium lactate ethyl ester, titanium triethanolaminate, polyhydroxytitanium stearate and the like.

For the undercoat layer, a white pigment is added to the above binder solution and dispersed by a method such as a colloid mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill or a paint shaker. Can be formed by applying. When the thickness of the undercoat layer is increased, the concealment of the irregularities of the conductive substrate is improved, so that the image defect is generally reduced, but the electrical repeatability is also deteriorated. Therefore, it is desirable that the film thickness is in the range of 0.2 to 5 μm.

A photosensitive layer is formed on the undercoat layer.
The photosensitive layer may basically have either a single layer structure or a laminated structure in which the functions are separated. However, in the present invention, since the photosensitive layer is excellent in performance such as stability and environmental change, charge generation is performed in the photosensitive layer. The layer and the charge transport layer are sequentially stacked to be formed. Further, it is possible to form a surface protective layer if necessary.

The charge generation layer is formed by forming a charge generation substance by vacuum vapor deposition or by dispersing the charge generation substance together with a binder resin in an organic solvent and applying it. As the charge generation material,
Amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, zinc oxide, inorganic photoconductors such as titanium oxide, metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, Various phthalocyanine pigments such as tin phthalocyanine and gallium phthalocyanine, various organic pigments and dyes such as squarylium-based, anthanthrone-based, perylene-based, azo-based, anthroquinone-based, pyrene-based, pyrylium salts and thiapyrylium salts are used. In addition, these organic pigments generally have several types of crystal, and in particular, various crystal types such as α and β are known for phthalocyanine pigments, but pigments that provide sensitivity suitable for the purpose If any, any crystal type may be used.

Examples of the binder resin in the charge generation layer include the following. That is, polycarbonate resin such as bisphenol A type or bisphenol Z type, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer Resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like. These binder resins can be used alone or in combination of two or more. The compounding ratio (weight ratio) of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10.
The thickness of the charge generation layer is generally 0.01 to 5 μm.
m, preferably 0.05 to 2.0 μm. As a method of dispersing the charge generating material in the resin,
A method such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill or a colloid mill can be used.

On the other hand, the charge transport layer is composed of a charge transport material and a binder resin. Examples of the charge transport material include those shown below. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3 Pyrazoline derivatives such as-(p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, aromatic tertiary amino compounds such as triphenylamine and dibenzylaniline, N, N'-diphenyl-N, N '. -Bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-
Aromatic tertiary diamino compounds such as diamine, 3- (4 '
1,2 such as dimethylaminophenyl) -5,6-di- (4'-methoxyphenyl) -1,2,4-triazine
4-triazine derivatives, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2,3-di (p-
Benzofuran derivatives such as methoxyphenyl) -benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N- Hole-transporting substances such as vinylcarbazole and its derivatives; quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,
Examples include electron-transporting substances such as fluorenone compounds such as 4,5,7-tetranitro-9-fluorenone, xanthone compounds, thiophene compounds; and polymers having a group consisting of the above compounds in the main chain or side chain. To be
These charge transport materials can be used alone or in combination of two or more.

As the binder resin used in the charge transport layer, acrylic resin, polyarylate, polyester resin, bisphenol A type or bisphenol Z is used.
Type polycarbonate resin, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-
Examples thereof include butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber and other insulating resins, and polyvinyl carbazole, polyvinyl anthracene, polyvinyl pyrene and other organic photoconductive polymers.

The charge transport layer can be formed by coating a solution obtained by dissolving the above charge transport material and the binder resin in a suitable solvent and drying the solution. Examples of the solvent used for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, and chlorobenzene,
Acetone, ketones such as 2-butanone, methylene chloride,
Halogenated aliphatic hydrocarbons such as chloroform and ethylene chloride, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or mixed solvents thereof can be used. The compounding ratio of the charge transport material and the polycarbonate resin is preferably 10: 1 to 1: 5. The thickness of the charge transport layer is generally 5 to 50 μm, preferably 10 to 40.
It is set in the range of μm.

The photosensitive layer in the present invention comprises an antioxidant, a light stabilizer, and a heat stabilizer for the purpose of preventing deterioration of the photoreceptor due to ozone or oxidizing gas generated in an electrophotographic apparatus, or light and heat. Additives such as can be added. Examples of antioxidants include hindered phenols, hindered amines, paraphenylenediamines, aryl alkanes, hydroquinones, spirochromans, spiroindanones and their derivatives, organic sulfur compounds and organic phosphorus compounds. Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives. Further, at least one electron-accepting substance may be contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of the electron-accepting substance that can be used in the photoreceptor of the present invention include, for example, succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone,
Examples thereof include trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid and phthalic acid. Of these, fluorenone series, quinone series,
A benzene derivative having an electron-withdrawing substituent such as Cl, CN or NO ₂ can be particularly preferably used.

The coating can be carried out using a coating method such as a dip coating method, a spray coating method, a ring coating method, a bead coating method, a blade coating method or a roller coating method. Drying
It is preferable to heat-dry after touch-drying at room temperature.
The heat drying is preferably performed at a temperature of 30 ° C. to 200 ° C. for a time in the range of 5 minutes to 2 hours.

If desired, a surface protective layer can be formed on the photosensitive layer. Examples of the surface protective layer include an insulating resin protective layer and a low resistance protective layer in which a resistance adjusting agent is added to the insulating resin. In the case of the low resistance protective layer, for example, a layer in which conductive fine particles are dispersed in an insulating resin can be used. As conductive fine particles, the electric resistance is 10 ⁹ Ω
Fine particles having an average particle size of 0.3 μm or less, preferably 0.1 μm or less, having a color of white or gray or bluish white at cm or less, and examples thereof include molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, and oxide. Examples thereof include titanium, indium oxide, a solid solution of tin oxide and antimony or antimony oxide, a mixture thereof, a mixture of these metal oxides in a single particle, or a coated material. Among them, tin oxide, and a solid solution of tin oxide and antimony or antimony oxide are preferably used because they can appropriately adjust the electric resistance and can make the protective layer substantially transparent ( JP-A-57-30847, JP-A-57-128
344). Examples of the insulating resin include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, and polyacrylamide.

The electrophotographic photoreceptor of the present invention can be used in electrophotographic apparatuses such as light lens type copying machines, laser beam printers emitting near infrared light or visible light, digital copying machines, LED printers, laser facsimiles and the like. it can. For the electrophotographic photosensitive member of the present invention, a one-component or two-component regular developer or reversal developer can be used.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 1 4 parts by weight of polyvinyl butyral resin (S-REC BM
-S, Sekisui Chemical Co., Ltd.) was dissolved in 200 parts by weight of n-butyl alcohol, and 80 parts of alumina silica coated rutile type titanium oxide (R7E, Sakai Chemical Co., Ltd.) was mixed,
Dispersion treatment was performed with an ultrasonic disperser to obtain a mill base. To this mill base, 40 parts of n-butyl alcohol, 1 part by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and 1 part by weight of a mixture of organic silane compounds (γ-aminopropyltrimethoxysilane) were additionally mixed, stirred and mixed. A coating liquid for forming a pulling layer was obtained. The obtained coating liquid is applied onto an aluminum base material of 40 mmφ,
After drying, an undercoat layer having a film thickness of 1 μm was formed.

A mixture of 15 parts by weight of metal-free phthalocyanine, 10 parts by weight of polyvinyl butyral resin (S-REC, manufactured by BM-S Sekisui Chemical Co., Ltd.), and 300 parts by weight of n-butyl alcohol was dispersed in a sand mill for 4 hours. The resulting dispersion was applied onto the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm. Next, N, N'-
Diphenyl-N, N'-bis (3-methylphenyl)-
4 parts by weight of [1,1′-biphenyl] -4,4′-diamine and bisphenol Z polycarbonate resin (molecular weight 4
6 parts by weight and 80 parts by weight of chlorobenzene were added and dissolved. The resulting solution was applied and dried to form a charge transport layer having a film thickness of 20 μm, and an electrophotographic photoreceptor having three layers was produced. When the cross section of the obtained electrophotographic photosensitive member was observed with an electron microscope, voids were present in the undercoat layer, and the ratio thereof was about 15 in terms of area.
% (Volume) was confirmed. The content of the binder in the undercoat layer was 14% by volume. A laser beam printer (XP-1
(1. made by Fuji Xerox Co., Ltd.), an image was obtained by performing a copying operation, and the image quality was examined. The results are shown in Table 1.

Comparative Example 1 4 parts by weight of polyvinyl butyral resin (S-REC BM
-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 100 parts by weight of n-butyl alcohol, and 20 parts of alumina-silica-coated rutile type titanium oxide (R7E, manufactured by Sakai Chemical Co., Ltd.) was mixed with the ultrasonic dispersion device. The dispersion treatment was performed to obtain a mill base. A mixture of 80 parts of n-butyl alcohol, 1 part by weight of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (γ
(Aminopropyltrimethoxysilane) 1 part by weight was additionally mixed and stirred to obtain a coating liquid for forming an undercoat layer. The obtained coating liquid was applied onto an aluminum substrate having a diameter of 40 mm and dried to form an undercoat layer having a film thickness of 1 μm. On this, a charge generation layer and a charge transport layer were laminated under the same conditions as in Example 1 to prepare an electrophotographic photoreceptor having three layers. When the cross section of the obtained electrophotographic photosensitive member was observed with an electron microscope, it was confirmed that there were no voids in the undercoat layer and the voids of titanium oxide were occupied by the resin component. The content of the binder in the undercoat layer was 50% by volume. The results obtained in the same manner as in Example 1 are shown in Table 1.

[0030]

[Table 1]

Example 2 1 part by weight of polyvinyl butyral resin (ESREC BM
-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 100 parts by weight of ethyl alcohol to obtain a solution, and anatase type titanium oxide (TA
300 parts, manufactured by Fuji Titanium Co., Ltd.) and 10 parts by weight of zinc oxide were mixed and dispersed with an ultrasonic disperser to obtain a mill base. To this mill base. n-butyl alcohol 4
0 part and 1 part by weight of an organic zirconium compound (acetylacetone zirconium butyrate) were additionally mixed and stirred to obtain a coating liquid for forming an undercoat layer. The obtained coating liquid is applied and dried on an aluminum substrate having a diameter of 40 mm,
An undercoat layer having a film thickness of 1 μm was formed.

A mixture of 15 parts by weight of titanyl phthalocyanine, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Unicar Co., Ltd.), and 300 parts by weight of n-butyl alcohol was dispersed in a sand mill for 4 hours.
The resulting dispersion is applied onto the undercoat layer and dried,
A charge generation layer having a thickness of 0.2 μm was formed. Then N,
4 parts by weight of N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine and 6 parts by weight of bisphenol Z polycarbonate resin (molecular weight 40,000) Was added to 80 parts by weight of chlorobenzene and dissolved. The resulting solution was applied and dried to form a charge transport layer having a film thickness of 20 μm, and an electrophotographic photoreceptor having three layers was produced. When the cross section of the obtained electrophotographic photosensitive member was observed with an electron microscope, it was confirmed that voids were present in the undercoat layer, and the ratio thereof was about 20% (volume) in terms of area. It was The content of the binder in the undercoat layer was 14% by volume. A laser beam printer (XP
-11, manufactured by Fuji Xerox Co., Ltd.), and a copy operation was performed to examine the image quality. The results are shown in Table 2.

Comparative Example 2 4 parts by weight of polyvinyl butyral resin (S-REC BM
-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 100 parts of ethyl alcohol to obtain a solution, and anatase type titanium oxide (TA30
0, manufactured by Fuji Titanium Co., Ltd.) and 10 parts by weight of zinc oxide were mixed and dispersed for 2 hours by a sand grind mill to obtain a mill base. To this mill base, 40 parts of n-butyl alcohol and 4 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) were additionally mixed and stirred to obtain a coating liquid for forming an undercoat layer. The obtained coating liquid was applied and dried on a 40 mmφ aluminum substrate to form an undercoat layer having a film thickness of 1 μm. A mixture of 15 parts by weight of titanyl phthalocyanine, 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (Nippon Unicar VMCH), and 300 parts by weight of n-butyl alcohol was dispersed in a sand mill for 4 hours. The resulting dispersion was applied onto the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm. Next, N, N'-diphenyl-N, N'-
Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine 4 parts by weight and bisphenol Z
6 parts by weight of a polycarbonate resin (molecular weight 40,000) and 80 parts by weight of chlorobenzene were added and dissolved. The resulting solution was applied and dried to form a charge transport layer having a film thickness of 20 μm, and an electrophotographic photoreceptor having three layers was produced. When the cross section of the obtained electrophotographic photosensitive member was observed with an electron microscope, it was confirmed that there were no voids in the undercoat layer and the voids of titanium oxide were occupied by the resin component.
The content of the binder in the undercoat layer was 40% by volume. Table 2 shows the results of evaluation performed in the same manner as in Example 1.

[0034]

[Table 2]

Examples 3 and 4 and Comparative Examples 3 and 4 1 part by weight of polyvinyl butyral resin (S-REC BM
-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 100 parts by weight of n-butyl alcohol, and the obtained solution was added with titanium oxide particles (A11).
50 parts by weight (Example 3), 35 parts by weight (Example 4), 10 parts by weight (Comparative Example 3), and 5 parts by weight (Comparative Example 4), and mixed. Dispersion treatment was performed with an ultrasonic disperser to obtain a mill base. To this mill base, 40 parts by weight of n-butyl alcohol and 2 parts by weight of an organic zirconium compound (acetylacetone zirconium butyrate) were additionally mixed and stirred to obtain a coating liquid for forming an undercoat layer. The obtained coating liquid was applied onto an aluminum base material having a diameter of 40 mm and dried to form an undercoat layer having a film thickness of 1.5 μm.

A mixture of 15 parts by weight of metal-free phthalocyanine, 10 parts by weight of polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.), and 300 parts by weight of n-butyl alcohol was dispersed in a sand mill for 4 hours. The resulting dispersion was applied onto the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm. Next, N, N'-
Diphenyl-N, N'-bis (3-methylphenyl)-
4 parts by weight of [1,1′-biphenyl] -4,4′-diamine and bisphenol Z polycarbonate resin (molecular weight 4
6 parts by weight and 80 parts by weight of chlorobenzene were added and dissolved. The resulting solution was applied and dried to form a charge transport layer having a film thickness of 20 μm, and an electrophotographic photoreceptor having three layers was produced. The obtained electrophotographic photosensitive member was mounted on a laser beam printer (XP-11, manufactured by Fuji Xerox Co., Ltd.), and a copying operation was performed to examine the image quality of the obtained image. The results are shown in Table 3 together with the ratio of voids in the undercoat layer.

[0037]

[Table 3]

[0038]

INDUSTRIAL APPLICABILITY As described above, the electrophotographic photosensitive member of the present invention has a void of 10% or more in the undercoat layer containing a white pigment, and therefore, it was used in an electrophotographic apparatus using coherent light. In this case, the occurrence of interference fringe patterns can be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an electrophotographic photosensitive member of the present invention.

FIG. 1 is a schematic sectional view of a conventional electrophotographic photosensitive member.

[Explanation of symbols]

1 ... Conductive substrate, 2 ... Undercoat layer, 21 ... White pigment, 22
... voids, 23 ... resin, 3 ... charge generation layer, 4 ... charge transport layer.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 21, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic sectional view of a conventional electrophotographic photosensitive member.

[Explanation of Codes] 1 ... Conductive substrate, 2 ... Undercoat layer, 21 ... White pigment, 22
... voids, 23 ... resin, 3 ... charge generation layer, 4 ... charge transport layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Miyamoto 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (8)

[Claims] 1. An electrophotographic photosensitive member comprising an electrically conductive substrate, on which an undercoat layer, a charge generation layer and a charge transport layer are successively laminated, wherein the undercoat layer contains a white pigment and has a volume fraction of 1
An electrophotographic photoreceptor having voids of 0% or more. 2. An electrophotographic photosensitive member characterized in that the undercoat layer contains 25% by volume or less of a binder. 3. The white pigment has an average particle size of 0.01 to 1 μm.
2. The electrophotographic photosensitive member according to claim 1, which is the titanium oxide fine particle. 4. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains a polyvinyl acetal resin as a binder. 5. The electrophotographic photoreceptor according to claim 4, wherein the polyvinyl acetal resin is a polyvinyl butyral resin. 6. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains an organometallic compound as a binder. 7. The electrophotographic photosensitive member according to claim 6, wherein the organometallic compound is an organozirconium compound. 8. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains a silane coupling agent as a binder.