JPH0895263A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To prevent the conversion of a coating soln. into gel and the crystalli zation of a resin binder and to maintain superior electrophotographic characteristics over a long period of time by using specified polyarylate as the resin binder of a photosensitive layer. CONSTITUTION: Polyarylate having structural units represented by formulae I, II is used as a resin binder forming a photosensitive layer. The mol fraction of the structural units represented by the formula I to those represented by the formula II has been regulated so as to satisfy 0.05<=I/(I+II)<=1.00. The inherent viscosity (ηinh) of the polyarylate measured at 1.0g/dl concn. in tetrachloroethane as a solvent at 25 deg.C is 0.25-1.00. In the formulae I, II, each of R1 , R2 , R13 and R14 is H, halogen or 1-4C alkyl, each of R3 -R12 is H or 1-4C alkyl, X is O, S, 1-12C alkylene, etc., and Y is phenylene, biphenylene, naphthylene, 1-12C aliphatic hydrocarbon, etc.

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 which can maintain excellent electrophotographic characteristics for a long time.

[0002]

2. Description of the Related Art Laminated electrophotographic photoconductors and single-layered electrophotographic photoconductors are known as electrophotographic photoconductors. A photosensitive layer is formed on at least two layers in which a charge generation layer for generating charges by exposure and a charge transport layer for transporting charges are laminated (the two layers are reversed). In the present invention, this is also referred to as an inverse layer type, which is also referred to as a laminated electrophotographic photoreceptor, and in a single layer type electrophotographic photoreceptor, a charge generating substance and a charge transporting substance are dispersed in a binder resin on a conductive substrate. A photosensitive layer consisting of the above single layer is formed.

The binder resin of the photosensitive layer of the electrophotographic photosensitive member (the photosensitive layer in the single-layer type electrophotographic photosensitive member and the charge transport layer in the laminated type electrophotographic photosensitive member) is
Polycarbonate resins made from 2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as bisphenol-A) are widely used. Since the polycarbonate resin using bisphenol-A as a raw material has good compatibility with the charge transporting substance, the electrophotographic photoreceptor having a photosensitive layer using the bisphenol-A as a binder resin has good electrical characteristics and is relatively mechanical. It has the characteristic that the target strength is high.

However, it has been revealed that the following problems occur when the photosensitive layer is formed by using a polycarbonate resin made of bisphenol-A as a binder resin. (1) When a photosensitive layer was coated on a base during the preparation of a photosensitive member, the coating solution may gel or the resin may crystallize in the photosensitive layer depending on the solvent used. Then, in the gelled portion or the crystallized portion in the coating layer, there is no light attenuation, the electric charge remains as a residual potential, and appears as a defect in image quality. (2) In the case of a general negative charging type electrophotographic photosensitive member, the photosensitive layer using a polycarbonate resin using bisphenol-A as a raw material has poor adhesion to the base, so that it is easy to peel off or lacks in surface hardness. Therefore, there is a problem that the printing life is shortened due to scratches or abrasion of the surface. The term “underlying layer” as used herein refers to a charge generation layer in the case of a laminated type photoconductor, a conductive substrate in the case of a reverse layer type photoconductor, and a conductive substrate in the case of a single layer type photoconductor.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is that the coating solution is gelated or the binder resin in the photosensitive layer is crystallized during the production of the electrophotographic photosensitive member. Provided is an electrophotographic photosensitive member which has good adhesion between a photosensitive layer and a base, excellent mechanical strength of the photosensitive layer and good printing durability, and which can maintain excellent electrophotographic characteristics for a long period of time. To do.

[0006]

Means for Solving the Problems As a result of intensive studies to solve such problems, the present inventors have found that polyarylate containing a specific aliphatic ring as a structural unit is used as a binder resin for a photosensitive layer. Based on these findings, the present invention has been accomplished based on the finding that the problems found in the electrophotographic photosensitive member as described above can be solved.

That is, the gist of the present invention is, in an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the binder resin forming the photosensitive layer is a structural unit represented by the following formulas (1) and (2). Having a molar fraction of the structural units represented by the formulas (1) and (2) is 0.05 ≦ [(1) / {(1) + (2)}] ≦ 1.00.
And an inherent viscosity (ηinh .: measured at 25 ° C. with tetrachloroethane as a solvent and a binder resin concentration of 1.0 g / dl) of 0.25 to 1.
And an electrophotographic photosensitive member.

[0008]

[Chemical 3]

[0009]

[Chemical 4]

[In the formula (1), R ₁ and R ₂ are each independently selected from a hydrogen atom, a halogen atom and an alkyl group having 1 to 4 carbon atoms, and R _{3 to} R ₁₂ are hydrogen atoms and 1 carbon atom.
Selected from an alkyl group of 4 to 4, X is selected from an oxygen atom, a sulfur atom, an alkylene group having 1 to 12 carbon atoms, an alkylidene group having 1 to 12 carbon atoms and a phenylalkylidene group, and Y is a phenylene group, a biphenylene group, Naphthylene group, aliphatic hydrocarbon group having 1 to 12 carbon atoms and 3 to carbon atoms
7 cyclic hydrocarbon groups. In equation (2),
R ₁₃ and R ₁₄ are each independently selected from a hydrogen atom, a halogen atom and an alkyl group having 1 to 4 carbon atoms, Z is a single bond, an oxygen atom, a sulfur atom, an alkylene group having 1 to 12 carbon atoms, and 1 carbon atom. ~ 12 alkylidene groups and phenylalkylidene groups, Y is a phenylene group, a biphenylene group,
It is selected from a naphthylene group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms and a cyclic hydrocarbon group having 3 to 7 carbon atoms. ]

The present invention will be described in detail below. The polyarylate used as the binder resin of the photosensitive layer of the electrophotographic photoreceptor of the present invention is a specific polyarylate having the structural unit represented by the formula (1) and the structural unit represented by the formula (2). What is preferable as the dihydric phenol constituting the structural unit represented by the formula (1) is the following formula (3) to
The dihydric phenol represented by (18) may be mentioned, and among these, one kind or two or more kinds may be copolymerized and used. Among these, it is preferable to use the dihydric phenol represented by the formula (3).

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7]

Examples of the dihydric phenol constituting the structural unit represented by the formula (2) include bis (4-hydroxyphenyl) methane and 1,1-bis (4-hydroxyphenyl).
Ethane, 1,2-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl)
Butane, 2,2-bis (4-hydroxyphenyl) octane, 4,4-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) -1,1
-Diphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylmethane, bis (4-
Hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3-methyl-
4-hydroxyphenyl) propane, 2- (3-methyl-4-hydroxyphenyl) -2- (4-hydroxyphenyl) -1-phenylethane, bis (3-methyl-4)
-Hydroxyphenyl) sulfide, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) methane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 2 , 2-bis (2-methyl-4-hydroxyphenyl) propane, 1,1-bis (2-butyl-4-hydroxy-5-methylphenyl) butane, 1,1-bis (2
-Tert-butyl-4-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-tert-butyl-
4-hydroxy-5-methylphenyl) propane, 1,
1-bis (2-tert-butyl-4-hydroxy-5)
-Methylphenyl) butane, 1,1-bis (2-ter
t-butyl-4-hydroxy-5-methylphenyl) isobutane, 1,1-bis (2-tert-butyl-4-
Hydroxy-5-methylphenyl) heptane, 1,1-
Bis (2-tert-butyl-4-hydroxy-5-methylphenyl) -1-phenylmethane, 1,1-bis (2-tert-amyl-4-hydroxy-5-methylphenyl) butane, bis (3- Chloro-4-hydroxyphenyl) methane, bis (3,5-dibromo-4-hydroxyphenyl) methane, 2,2-bis (3-chloro-)
4-hydroxyphenyl) propane, 2,2-bis (3
-Fluoro-4-hydroxyphenyl) propane, 2,
2-bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-difluoro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) ) Propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxy-5)
-Chlorophenyl) propane, 2,2-bis (3,5-
Dichloro-4-hydroxyphenyl) butane, 2,2-
Bis (3,5-dibromo-4-hydroxyphenyl) butane, 1-phenyl-1,1-bis (3-fluoro-4)
-Hydroxyphenyl) ethane, bis (3-fluoro-)
4-hydroxyphenyl) ether, 1,1-bis (3
-Cyclohexyl-4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl)-
3,3,5-trimethylcyclohexane, 1,1,1,
3,3,3-Hexafluoro-2,2-bis (4-hydroxyphenyl) propane, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxy-3,3'-dimethylbiphenyl, 4,4'- Dihydroxy-2,2'-dimethylbiphenyl, 4,4'-dihydroxy-3,3 '
-Dicyclohexylbiphenyl, 4,4'-dihydroxy-3,3'-difluorobiphenyl, 3,3 ', 5
Examples thereof include 5'-tetramethyl-4,4'-dihydroxybiphenyl, 4,4'-dihydroxybenzophenone, resorcinol, hydroquinone and bisphenolfluorene. These dihydric phenols may be used alone or in combination of two or more. Particularly preferred are 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane and 2,2-bis (3-methyl-4-hydroxyphenyl) propane.

Examples of the divalent carboxylic acid used in producing the polyarylate having the structural units represented by the formulas (1) and (2) include terephthalic acid, isophthalic acid, orthophthalic acid and 2,6-naphthalene. Dicarboxylic acid, diphenic acid, 4,4′-dicarboxydiphenyl ether, bis (p-carboxyphenyl) alkane,
4,4'-dicarboxyphenyl sulfone, oxalic acid,
Aliphatic dicarboxylic acids such as malonic acid, succinic acid and adipic acid can be mentioned. These divalent carboxylic acids can be used alone or in combination of two or more.

In this polyarylate, the molar fraction of the structural units represented by the formulas (1) and (2) is 0.05 ≦.
[(1) / {(1) + (2)}] ≦ 1.00 is satisfied. When (1) / {(1) + (2)} is less than 0.05, the effect of the present invention cannot be obtained, and the gelation of the coating liquid, the crystallization of the photosensitive layer or the charge transport layer, etc. Is not achieved and the printing life is not improved, and the adhesion to the substrate is deteriorated.

The inherent viscosity (ηinh.) At 25 ° C. of a solution having a concentration of 1 g / dl in which tetraarylethane of polyarylate containing such a specific aliphatic ring as a structural unit is a solvent is 0.25 to 1.00. is there. When the inherent viscosity is less than 0.25, the mechanical strength is low, the surface strength of the layer used as the binder resin is insufficient, the photoreceptor is worn, and the printing life is shortened. On the other hand, if the inherent viscosity exceeds 1.0, the solution viscosity of the polyarylate increases, which may make it difficult to manufacture the photoreceptor by the solution coating method.

As a method for producing a polyarylate containing an aliphatic ring as a structural unit as described above, a solution polymerization method (A. Conix Ind. Eng.
m. 51 147 1959, Japanese Patent Publication No. 37-5599
Gazette), a melt polymerization method in which a divalent carboxylic acid and a divalent phenol are heated in the presence of acetic anhydride, and a melt polymerization method in which a divalent carboxylic acid and a divalent phenol are heated in the presence of diallyl carbonate ( JP-B-38-26299), an interfacial polymerization method (WM EAREC) in which a divalent carboxylic acid halide dissolved in an organic solvent incompatible with water and a divalent phenol dissolved in an alkaline aqueous solution are mixed.
KSON J. Poly. Sci. XL399 195
It can be produced by a known method such as 9 years, Japanese Patent Publication No. 40-1959). Among them, the interfacial polymerization method is particularly preferably adopted.

The production method by the interfacial polymerization method will be described in more detail. The dihydric phenol having an aliphatic ring constituting the structural unit represented by the formula (1) and the structural unit represented by the formula (2) are constituted. An alkaline aqueous solution with a dihydric phenol is prepared, and then a polymerization catalyst, for example, a tertiary amine such as trimethylamine or triethylamine, a quaternary ammonium salt such as trimethylbenzylammonium chloride or tributylbenzylammonium chloride, or the like is added. . On the other hand, a solvent that is incompatible with water and dissolves polyarylate, such as methylene chloride, 1,2
-A solution prepared by dissolving a divalent carboxylic acid halide in a chlorine-based solvent such as dichloroethane, chloroform or chlorobenzene, an aromatic hydrocarbon such as toluene, benzene or xylene is mixed with the above alkaline solution, and the temperature is kept at 25 ° C or lower. The desired polyarylate (copolymer) can be obtained by carrying out the reaction while stirring at a temperature for 1 hour to 5 hours. Examples of the alkali that can be used here include sodium hydroxide and potassium hydroxide.

The method for controlling the molecular weight of the polyarylate having the structural units of the formulas (1) and (2) is not limited to the interfacial polymerization method, and a monofunctional substance may be added during the polymerization. Examples of the monofunctional substance used as the molecular weight regulator here include phenol, cresol, and p.
Examples thereof include monovalent phenols such as -tert-butylphenol, monovalent acid chlorides such as benzoic acid chloride and methanesulfonyl chloride.

The polyarylate having a specific aliphatic ring as described above can be used in various known electrophotographic photoreceptors as a binder resin for forming the photosensitive layer of the electrophotographic photoreceptor. Further, another binder resin may be added to the polyarylate and used within a range not impairing the object of the present invention. It is also possible to add an antioxidant or the like.

In the present invention, various known materials can be used as the conductive substrate material constituting the electrophotographic photosensitive member. For example, a conductive material such as aluminum, nickel, chromium, palladium, or graphite is coated on a plastic sheet such as a metal plate made of aluminum, brass, copper, nickel, steel, etc., a drum, or a metal sheet by vapor deposition, sputtering, coating, etc. For example, those that have been subjected to conductivity treatment, such as those where the surface of the metal drum has been subjected to metal oxide treatment such as electrode oxidation, or those that have been subjected to conductivity treatment on a substrate such as glass, plastic plate, cloth, or paper. Can be used.

As described above, in the multi-layer type electrophotographic photoreceptor, the photosensitive layer comprising at least two layers in which the charge generation layer and the charge transport layer are laminated is formed on the conductive substrate, and the single layer is formed. In the electrophotographic photoreceptor of the type, a photosensitive layer formed of a single layer in which a charge generating substance and a charge transporting substance are dispersed in a binder resin is formed on a conductive substrate. In the laminated electrophotographic photosensitive member, the charge generation layer is formed by forming a layer of the charge generation substance on the substrate which is the base thereof (on the charge transport layer in the reverse layer type) by vacuum deposition, sputtering, or the like. It can be obtained by forming a layer formed by binding a charge generating substance using a binder resin on a base substrate (on a charge transport layer in the reverse layer type). As a method for forming the charge generation layer when a binder resin is used, a known method can be used. Usually, a coating liquid in which a charge generation substance is dispersed or dissolved in a suitable solvent together with the binder resin is used as a base. It is preferably formed by coating on a substrate (on the charge transport layer in the reverse layer type) and drying.

The charge transport layer in the laminated electrophotographic photoreceptor is formed by forming a layer in which a charge transport substance is bound with a binder resin on a charge transport layer as an underlayer (or a substrate in the reverse layer type). can get. As a method for producing the charge transport layer, a known method can be used. Usually, the charge transport substance and the polyarylate having the structural unit represented by the formulas (1) and (2) are dispersed in a suitable solvent. Alternatively, it is preferable that the dissolved coating liquid is applied on the base and dried to form the film.

The photosensitive layer of the single-layer type electrophotographic photoreceptor contains a charge-generating substance and a charge-transporting substance. As a method for producing this photosensitive layer, a known method can be used. Formed by dispersing or dissolving the generating substance, the charge transporting substance, and the polyarylate having the structural unit represented by the above formulas (1) and (2) in a suitable solvent, applying the coating solution on a substrate, and drying. Preferably.

As the charge generating substance that can be used in the electrophotographic photosensitive member, various known substances can be used. Specifically, amorphous selenium, selenium simple substance such as trigonal selenium, selenium alloy such as selenium-tellurium, As.
₂ Se ₃ or other selenium compounds or selenium-containing compositions, zinc oxide, inorganic materials composed of Group II and IV elements such as CdS—Se, oxide semiconductors such as titanium oxide, silicon-based materials such as amorphous silicon And various organic materials such as metal or non-metal phthalocyanine, cyanine, anthracene, bisazo compound, pyrene, perylene, pyrylium salt, thiapyrylium salt, polyvinylcarbazole, and squarylium pigment. These charge generating substances may be used alone or in combination of two or more.

Examples of the charge-transporting substance in the electrophotographic photosensitive member include conventionally used electron-transporting substances and hole-transporting substances. As an example of such an electron transport material,
Chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-
Fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-trinitro-9-dicyanomethylenefluorenone, 2,4,5,7-tetranitroxanthone, 2,4,9-trinitro In addition to thioxanthone, 3,5-dimethyl-3 ', 5'-di-tert-
Examples thereof include electron withdrawing substances such as diphenoquinone derivatives such as butyl-4 ′, 4′-diphenoquinone, and polymer substances thereof. These may be used alone or in combination of two or more.

Examples of the hole transport material include pyrene and N-.
Ethylcarbazole, N-isopropylpropicarbazole,
N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,
N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-
3-methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-
α-naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone,
1,3,3-Trimethylindolenine-ω-aldehyde-N, N-diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 1-phenyl-1,2,3,4- Hydrazones such as tetrahydroquinoline-6-carboxaldehyde-1 ′, 1′-diphenylhydrazone, 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1-phenyl-3- ( p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazone, 1- [quinolyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl)
Pyrazoline, 1- [repidyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1- [6-methoxy-pyridyl (2)]-3- (p-diethylaminostyryl) ) -5
(P-diethylaminophenyl) pyrazolin, 1- [pyridyl (5)]-3- (p-diethylaminophenyl)
Pyrazoline, 1- [pyridyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (p
-Diethylaminostyryl) -4-methyl-5- (p-
Diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (α-methyl-p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1-phenyl-3- (p-diethylaminostyryl)- 4-methyl-5- (p-diethylaminophenyl) pyrazoline, 1-phenyl-3- (α-benzyl-
Pyrazolines such as p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline and spiropyrazoline, 2- (p-diethylaminostyryl) -δ
-Oxazole compounds such as diethylaminobenzoxazole, 2- (p-diethylaminophenyl) -4- (p-dimethylaminophenyl) -5- (2-chlorophenyl) oxazole, 2- (p-diethylaminostyryl) -6-diethylaminobenzo Thiazole-based compounds such as thiazole, triarylmethane-based compounds such as bis (4-diethylamino-2-methylphenyl) phenylmethane, 1,1-bis (4-N, N-diethylamino-2-methylphenyl) heptane, 1 , 1, 2, 2-
Polyarylamines such as tetrakis (4-N, N-diethylamino-2-methylphenyl) ethane, N,
N'-diphenyl-N, N'-bis (methylphenyl)
Benzidine, N, N'-diphenyl-N, N'-bis (ethylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (propylphenyl) benzidine,
N, N'-diphenyl-N, N'-bis (butylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (isopropylphenyl) benzidine, N, N'-diphenyl-N, N'- Benzidine compounds such as bis (tert-butylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (isobutylphenyl) benzidine and N, N'-diphenyl-N, N'-bis (chlorophenyl) benzidine Or a butadiene compound, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, organic polysilane, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin and the like. To be These may be used alone or in a mixture of two or more.

The binder resin in the charge generating layer in the above-mentioned laminated electrophotographic photosensitive member is not particularly limited, and various known resins can be used. For example, polystyrene, polyvinyl chloride, polyvinyl acetate,
Heat of vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, styrene-acrylonitrile copolymer, polycarbonate, polyamide, polyarylate, polyester, polyketone, polyacrylamide, butyral resin, ABS resin, etc. Thermosetting resins such as plastic resins, polyurethane, epoxy resins, and phenol resins can be used. In addition, as the binder resin in the charge generation layer, the polyarylate having the specific aliphatic ring of the invention as a structural unit can also be used.

Solvents for the coating liquid used in preparing the charge generation layer and charge transport layer of the laminated electrophotographic photoreceptor and the photosensitive layer of the single-layer electrophotographic photoreceptor include benzene, toluene, xylene and chlorobenzene. , Aromatic solvent such as dichlorobenzene, ketone solvent such as acetone, methyl ethyl ketone, cyclohexanone, alcohol solvent such as methanol, ethanol, propanol, isopropanol, methyl cellosolve, ethyl cellosolve, ester such as ethyl acetate, methyl acetate System solvent, carbon tetrachloride, chloroform, methylene chloride, 1,2-dichloroethane, tetrachloroethane, 1,1,1,3,3,3-
Halogen-based solvents such as hexafluoroisopropanol, ether-based solvents such as tetrahydrofuran and dioxane, and other acetonitrile, dimethylformamide, dimethylsulfoxide, diethylformamide, etc. are used, and these can be used alone or in a mixture of two or more. You may. The application of the coating liquid can be carried out using various coating devices such as known ones. For example, an applicator, a spray coater, a bar coater, a tip coater, a roll coater, a dip coater, a doctor blade, etc. are mentioned.

As described above, by using the polyarylate having a specific aliphatic ring introduced into the main chain as the binder resin forming the photosensitive layer of the electrophotographic photoreceptor, the compatibility with the charge generating substance and the charge transporting substance is improved. Therefore, the coating liquid does not gel or the resin does not crystallize during the preparation of the photoreceptor, and the adhesiveness to the substrate is excellent, and the mechanical strength is excellent.

[0033]

EXAMPLES Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The method for evaluating the electrophotographic photosensitive member is shown below. (A) Stability of coating liquid The coating liquid was allowed to stand for one month, and it was visually judged whether the liquid became cloudy or gelled. (B) Presence or absence of crystallization during coating After the coating liquid was applied to the charge generation layer, it was visually determined whether or not the film became cloudy. (C) Electrophotographic characteristic evaluation -6k using an electrostatic charging tester manufactured by Kawaguchi Denki Seisakusho
Perform corona discharge and V, the initial surface potential (V _0), the residual potential after light irradiation for 5 seconds (V _R), half-decay exposure (E _1/2)
Was measured. (D) Abrasion resistance of photosensitive layer 200 g using a Suga abrasion tester manufactured by Suga Testing Instruments Co., Ltd.
The sample is reciprocated 1200 times on the worn paper under the load of
The change in the amount of wear thereafter was measured.

Example 1 After adding 600 ml of water to a 1500 ml container, 52.43 g of sodium hydroxide, 21.21 g of the dihydric phenol represented by the above formula (3) and 0.20 g of p-tert-butylphenol were dissolved. Then, 0.5 mol% of a polymerization catalyst (trimethylbenzylammonium chloride) is added to the dihydric phenol, and the mixture is vigorously stirred. Separately, an equal mixture of terephthalic acid chloride and isophthalic acid chloride (hereinafter abbreviated as MPC) was used as 13.4%.
2 g is measured and dissolved in 300 ml of methylene chloride. This methylene chloride solution was added to the previously prepared alkaline aqueous solution with stirring to start polymerization. The polymerization reaction temperature was adjusted to 25 ° C or lower. The polymerization time was 3 hours, and then acetic acid was added to the system to terminate the polymerization reaction. Washing with water was repeated until the aqueous phase became neutral. After completion of the washing, the mixture was slowly added to methanol with stirring to precipitate polyarylate. Further, by filtering and drying, 30 g of polyarylate containing an aliphatic ring as a structural unit was obtained. When the inherent viscosity of the obtained polyarylate was measured at 25 ° C. using a tetrachloroethane solvent, it was 0.735.

Example 2 20.91 g of dihydric phenol represented by the above formula (3), p
-Tert-butylphenol 0.48 g, MPC1
Polyarylate was obtained in the same manner as in Example 1 except that 3.43 g and 51.77 g of sodium hydroxide were used. The inherent viscosity of this sample was 0.513.

Example 3 20.72 g of dihydric phenol represented by the above formula (3), p
-Tert-butylphenol 0.67 g, MPC1
Polyarylate was obtained in the same manner as in Example 1 except that 3.44 g and 51.36 g of sodium hydroxide were used. The inherent viscosity of this sample was 0.320.

Example 4 7.33 g of the dihydric phenol represented by the above structural formula (3),
2,2-bis (4-hydroxyphenyl) propane 1
2.04 g, p-tert-butylphenol 0.57
g, MPC 15.70 g, sodium hydroxide 22.91
Polyarylate was obtained in the same manner as in Example 1 except that g was used. The inherent viscosity of this sample was 0.686.

Example 5 Dihydric phenol 11.66 represented by the above structural formula (3)
g, 2,2-bis (4-hydroxyphenyl) propane 8.21 g, p-tert-butylphenol 0.54
g, MPC 14.98 g, sodium hydroxide 32.12
Polyarylate was obtained in the same manner as in Example 1 except that g was used. The inherent viscosity of this sample was 0.583.

Example 6 15.61 of dihydric phenol represented by the above structural formula (3)
g, 2,2-bis (4-hydroxyphenyl) propane 4.71 g, p-tert-butylphenol 0.52
g, polyarylate was obtained in the same manner as in Example 1 except that 40.51 g of sodium hydroxide was used. The inherent viscosity of this sample was 0.546.

Example 7 11.28 of the dihydric phenol represented by the above structural formula (3)
g, 2,2-bis (2-methyl-4-hydroxyphenyl) propane 8.91 g, p-tert-butylphenol 0.52 g, MPC 14.49 g, sodium hydroxide 31.62 g The method was used to obtain polyarylate. The inherent viscosity of this sample was 0.562.

Example 8 11.13 dihydric phenol represented by the above structural formula (3)
g, 1,1-bis (4-hydroxyphenyl) cyclohexane 9.20 g, p-tert-butylphenol 0.52 g, MPC 14.29 g, sodium hydroxide 3
Polyarylate was obtained in the same manner as in Example 1 except that 1.75 g was used. The inherent viscosity of this sample is 0.
It was 501.

Comparative Example 1 Dihydric phenol 21.46 shown in the structural formula (3) above
g, MPC 13.44 g, sodium hydroxide 52.99
Polyarylate was obtained in the same manner as in Example 1 except that g was used. The inherent viscosity of this sample was 1.173.

Comparative Example 2 20.44 dihydric phenol represented by the above structural formula (3)
g, p-tert-butylphenol 0.95 g, MP
Polyarylate was obtained in the same manner as in Example 1 except that 13.45 g of C and 50.75 g of sodium hydroxide were used. The inherent viscosity of this sample was 0.211.

Comparative Example 3 2,2-bis (4-hydroxyphenyl) propane 1
8.55 g, p-tert-butylphenol 0.61
g, MPC 16.93g, sodium hydroxide 7.34g
Polyarylate was obtained in the same manner as in Example 1 except that it was used. The inherent viscosity of this sample was 0.699.

Comparative Example 4 2,2-bis (2-methyl-4-hydroxyphenyl)
Polyarylate was obtained in the same manner as in Example 1 except that 19.36 g of propane, 0.57 g of p-tert-butylphenol, 15.73 g of MPC and 8.03 g of sodium hydroxide were used. The inherent viscosity of this sample is 0.
It was 687.

Comparative Example 5 1,1-bis (4-hydroxyphenyl) cyclohexane 19.67 g, p-tert-butylphenol 0.
55 g, MPC 15.27 g, sodium hydroxide 8.9
Polyarylate was obtained in the same manner as in Example 1 except that 7 g was used. The inherent viscosity of this sample is 0.541.
Met.

Comparative Example 6 A three-necked flask is equipped with a stirrer, a thermometer, a gas introduction pipe, and an exhaust pipe. After adding 600 ml of water to this three-necked flask, 11.26 g of sodium hydroxide, 26.09 g of 2,2-bis (4-hydroxyphenyl) propane, p
-Dissolve 0.86 g of tert-butylphenol,
Further, 0.5 mol% of a polymerization catalyst (trimethylbenzylammonium chloride) was added to the dihydric phenol. Then, 300 ml of methylene chloride was added to the system, and phosgene gas was introduced while vigorously stirring this. Phosgene was introduced from the cylinder into the flask through an empty air bottle, an air bottle containing water, and an empty air bottle.
The reaction temperature during the introduction of phosgene gas was adjusted to 25 ° C or lower. As the polycondensation reaction progresses, the viscosity of the organic phase in the system increases. Phosgene gas was added until the yellow color of the phosgene-hydrogen chloride complex disappeared. Thereafter, the polycondensation reaction was terminated by adding acetic acid, and washing with water was repeated until the aqueous phase became neutral. After completion of washing, the mixture was slowly added to methanol with stirring to precipitate the polycarbonate. Further, 30 g of polycarbonate was obtained by filtering and drying. When the inherent viscosity of the obtained polycarbonate was measured at 25 ° C. using a tetrachloroethane solvent, it was 0.702.

Manufacturing Method of Electrophotographic Photoreceptor Polyarylate synthesized as in Examples 1 to 8 and Comparative Examples 1 to 6 using a compound having a structure represented by the following formula (19) as a charge transport material Polycarbonate, using methylene chloride as a solvent, polyarylate or polycarbonate: charge transport material: methylene chloride =
A coating liquid having a component ratio of 1: 1: 8 (weight ratio) was prepared, and the obtained coating liquid was added to about 0.5 of oxotitanium phthalocyanine formed on a conductive substrate made of aluminum.
A 20 μm charge transport layer was provided on the charge generation layer having a thickness of μm by a dip coating method and drying.

[0049]

[Chemical 8]

Table 1 shows the production conditions and ηinh. Of the polyarylate or polycarbonate synthesized in Examples 1 to 8 and Comparative Examples 1 to 6, and Table 2 shows the stability of the coating liquid and the presence or absence of crystallization during coating. Table 3 shows the initial surface potential (V ₀ ), the residual potential after light irradiation for 5 seconds (V _R ), and the half-exposure amount (E _1/2 ).
Table 4 shows the results of abrasion resistance of the charge transport layer.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

EFFECTS OF THE INVENTION Since the electrophotographic photoreceptor of the present invention is constituted as described above, by using a polyarylate having a specific aliphatic ring introduced into the main chain as a binder resin forming a photosensitive layer. Since the compatibility with the charge-generating substance and the charge-transporting substance and the affinity with the solvent are improved, the coating liquid does not gel or the resin does not crystallize during the production of the photoreceptor. It also has excellent adhesion between the photosensitive layer and the base,
It has excellent mechanical strength and maintains electrophotographic properties even after long-term use. Therefore, the electrophotographic photosensitive member is excellent in practical use, and can be suitably used in various electrophotographic fields.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate, wherein the binder resin forming the photosensitive layer is a polyarylate having structural units represented by the following formulas (1) and (2). And the molar fraction of the structural units represented by the formulas (1) and (2) is 0.05 ≦ [(1) / {(1)
+ (2)}] ≦ 1.00 and an inherent viscosity (ηinh .: using tetrachloroethane as a solvent,
An electrophotographic photoreceptor, wherein the binder resin concentration is 1.0 g / dl and the binder resin concentration is 0.25 to 1.00. [Chemical 1] [Chemical 2] [In the formula (1), R ₁ and R ₂ are each independently selected from a hydrogen atom, a halogen atom and an alkyl group having 1 to 4 carbon atoms, and R _{3 to} R ₁₂ are hydrogen atoms and an alkyl group having 1 to 4 carbon atoms. X is an oxygen atom, a sulfur atom, or a carbon number of 1 to
Selected from a 12 alkylene group, an alkylidene group having 1 to 12 carbon atoms and a phenylalkylidene group, Y is a phenylene group, a biphenylene group, a naphthylene group, a carbon number of 1 to 12
Are selected from the aliphatic hydrocarbon groups and cyclic hydrocarbon groups having 3 to 7 carbon atoms. In the formula (2), R ₁₃ and R ₁₄ are each independently selected from a hydrogen atom, a halogen atom and an alkyl group having 1 to 4 carbon atoms, Z is a single bond, an oxygen atom, a sulfur atom,
Selected from an alkylene group having 1 to 12 carbon atoms, an alkylidene group having 1 to 12 carbon atoms and a phenylalkylidene group, and Y
Is selected from a phenylene group, a biphenylene group, a naphthylene group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, and a cyclic hydrocarbon group having 3 to 7 carbon atoms. ]