JPH0895262A - 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 polycarbonate as the resin binder of a photosensitive layer. CONSTITUTION: Polycarbonate 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 0.2<=I/(I+II)<=1.0. The inherent viscosity (ηinh) of the polycarbonate measured at 1.0g/di concn. in tetrachloroethane as a solvent at 25 deg.C is 0.2-1.0. 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 and each of X and Y is O, S, 1-12C alkylene, 1-12C alkylidene or phenylalkylidene.

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 comprising at least two layers in which a charge generating layer for generating charges upon exposure and a charge transporting layer for transporting charges are laminated (a layer in which the two layers are reversed is referred to as an inverse layer type). In the present invention, this is also referred to as a laminated electrophotographic photoreceptor, and in a single-layer electrophotographic photoreceptor,
A photosensitive layer is formed on a conductive substrate, which is a single layer in which a charge generating substance and a charge transporting substance are dispersed in a binder resin.

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 an ordinary negative charging type electrophotographic photosensitive member, the photosensitive layer using the polycarbonate resin of 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. In the case of a laminated type photoreceptor, the term “underlying” means a charge generation layer,
A reverse-layer type photoreceptor means a conductive substrate, and a single-layer type photoreceptor means a conductive substrate.

[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 when a polycarbonate containing a specific aliphatic ring as a structural unit is used as a binder resin for a photosensitive layer, The present invention has been achieved based on the findings 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 photosensitive member having a photosensitive layer on a conductive substrate, the binder resin forming the photosensitive layer is a structural unit represented by the formula (1) or (2). And a molar fraction of the structural units represented by formulas (1) and (2) is 0.2 ≦ [(1) / {(1) + (2)}] ≦ 1.0
And the inherent viscosity (ηinh .: tetrachloroethane was used as the solvent, and the binder resin concentration was 1.
The electrophotographic photoreceptor is characterized in that it is 0 g / dl and measured at 25 ° C.) is 0.2 to 1.0.

[0008]

[Chemical 3]

[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 each independently a hydrogen atom and a carbon atom. Selected from an alkyl group having 1 to 4 carbon atoms, X represents an oxygen atom, a sulfur atom, an alkylene group having 1 to 12 carbon atoms, and 1 to 12 carbon atoms.
Selected from the group consisting of alkylidene group and phenylalkylidene group. ]

[0010]

[Chemical 4]

[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, and Y is a single bond, an oxygen atom, a sulfur atom, or a carbon number. It is selected from the group consisting of alkylene groups having 1 to 12 carbon atoms, alkylidene groups having 1 to 12 carbon atoms and phenylalkylidene groups. ]

The present invention will be described in detail below. In the polycarbonate having a specific aliphatic ring structural unit used as the binder resin of the photosensitive layer of the electrophotographic photosensitive member of the present invention, as the dihydric phenol used for constituting the structural unit represented by the formula (1), From the following formula (3)
The dihydric phenol of (18) can 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).

[0013]

[Chemical 5]

[0014]

[Chemical 6]

[0015]

[Chemical 7]

The dihydric phenol used to form the structural unit represented by the formula (2) includes bis (4-hydroxyphenyl) methane, 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-hydroxy) Phenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 4,4-bis (4-hydroxyphenyl) heptane, 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-t
ert-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 (3,3
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 ', 5,5'-tetramethyl-4,
4'-dihydroxybiphenyl, 4,4'-dihydroxybenzophenone, resorcinol, hydroquinone,
Examples include bisphenol fluorene. These dihydric phenols can be used alone or in combination with 2
It is also possible to use more than one type together. Among them, 2, 2
-Bis (4-hydroxyphenyl) propane, 1,1-
Bis (4-hydroxyphenyl) cyclohexane, 2,
2-bis (3-methyl-4-hydroxyphenyl) propane is preferred.

In the polycarbonate used as the binder resin for forming the photosensitive layer, the molar fraction of the structural units represented by the formulas (1) and (2) is 0.2 ≦ [(1) / {(1 ) + (2)}] ≦ 1.0. When the molar fraction of the structural unit represented by the formula (1) is less than 0.2, the coating liquid gels or the resin in the photosensitive layer crystallizes, resulting in poor adhesion to the base. .
In addition, in this polycarbonate, the inherent viscosity (ηinh.) At 25 ° C of a solution having a concentration of 1 g / dl using tetrachloroethane as a solvent is 0.2 to 1.0. When the inherent viscosity is less than 0.2, the mechanical strength is low, the surface strength of the layer used as the binder resin is insufficient, the photosensitive layer is worn, and the printing life is shortened. On the other hand, when the inherent viscosity exceeds 1.0, the solution viscosity of the polycarbonate increases, which makes it difficult to manufacture the photosensitive layer by the coating method.

Examples of the method for producing the polycarbonate containing the specific aliphatic ring as a structural unit include ordinary production methods such as a transesterification method, a solution polymerization method and an interfacial polymerization method, which will be described below.

Transesterification Method For the above dihydric phenol and this dihydric phenol,
Stoichiometrically slightly more than the equivalent amount of diphenyl carbonate is added in the presence of a conventional carbonation catalyst to about 160
C. to 180.degree. C., normal pressure, and reaction for about 30 minutes under the condition of introducing an inert gas, and gradually reducing pressure over 2 hours at a temperature of about 180.degree. C. to 220.degree.
The prepolymerization is completed at r and 220 ° C. Then 10 Tor
r, 270 ° C. for 30 minutes, 5 Torr, 270 ° C. for 20 minutes
After reacting for 1 minute, post-condensation proceeds at 270 ° C. for 1.5 to 2 hours under a reduced pressure of 0.5 Torr or less, preferably 0.3 Torr to 0.1 Torr. Suitable carbonate-forming catalysts that can be used in this reaction are alkali metal and alkaline earth metal catalysts such as lithium-based catalysts, potassium-based catalysts, sodium-based catalysts, and tin-based catalysts. Examples thereof include lithium, potassium borohydride, potassium hydrogen phosphate, sodium hydroxide, sodium borohydride, calcium hydride, dibutyltin oxide, and stannous oxide. Among these,
It is preferable to use a potassium-based catalyst.

Solution Polymerization Method The above-mentioned dihydric phenol pyridine solution is prepared, and phosgene gas is introduced while vigorously stirring the solution. With the introduction of gas, pyridine hydrochloride precipitates and the solution becomes cloudy. Further, the reaction temperature is water-cooled to 30 ° C. or lower. The viscosity of the polymerization solution increases as the polycondensation reaction proceeds. Phosgene gas is introduced until the yellow color of the phosgene-hydrogen chloride complex disappears, and when this color disappears, the polymerization is terminated.

Interfacial Polymerization Method A solvent which is incompatible with water and dissolves the polycarbonate in the above-mentioned alkaline aqueous solution of the dihydric phenol, for example, a methylene chloride, 1,2-dichloroethane, chloroform, chlorobenzene or other chlorinated solvent. , Mixed with aromatic hydrocarbons such as toluene, benzene and xylene,
Then phosgene is introduced. Subsequently, 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, and the mixture is stirred at a temperature of 30 ° C or lower for 1 hour to 5 hours. By carrying out the reaction while carrying out the reaction, a desired polycarbonate copolymer can be obtained. Examples of the alkali that can be used here include sodium hydroxide and potassium hydroxide.

As a method for controlling the molecular weight of the polycarbonate, any of the above-mentioned production methods can be carried out by adding a monofunctional substance during the polymerization. Examples of the monofunctional substance used as the molecular weight regulator include monovalent phenols such as phenol, cresol and p-tert-butylphenol, and monovalent acid chlorides such as benzoic acid chloride and methanesulfonyl chloride.

A coating solution is prepared by using the polycarbonate containing a specific aliphatic ring obtained as a structural unit as a structural unit as a binder resin, and is coated on a base to form a photosensitive layer. That is, in the case of a single-layer type electrophotographic photoreceptor, a coating solution is prepared from a polycarbonate containing a specific aliphatic ring as a structural unit, a charge generating substance, a charge transporting substance and a solvent, and is coated on a substrate to be exposed. Form the layers. Further, in the case of a laminated type electrophotographic photoreceptor, a coating liquid is prepared from the above-mentioned polycarbonate containing a specific aliphatic ring as a structural unit, a charge-transporting substance and a solvent, and is applied onto a base to form a charge-transporting layer. To do. At this time, another binder resin may be mixed with the above-mentioned polycarbonate and used within a range not impairing the object of the present invention. It is also possible to add an antioxidant or the like.

As the conductive substrate forming the electrophotographic photosensitive member of the present invention, various known substrates can be used. Examples thereof include metal plates of aluminum, brass, copper, nickel, steel, etc., drums of these metals, and sheets of these metals. In addition, a conductive material such as aluminum, nickel, chromium, palladium, or graphite is coated on the plastic sheet by vapor deposition, sputtering, coating, etc., or the surface of the metal drum is oxidized by an electrode. Metal oxide treated, glass, plastic plate,
A substrate such as cloth or paper that has been subjected to a conductive treatment can be used.

As the charge generating substance, various known substances can be used. Specifically, amorphous selenium, simple selenium such as trigonal selenium, selenium alloys such as selenium-tellurium, selenium compounds such as As ₂ Se ₃ or selenium-containing compositions, zinc oxide, CdS-Se and the like II Inorganic materials consisting of Group IV and Group IV elements, oxide-based semiconductors such as titanium oxide, various inorganic materials such as silicon-based materials such as amorphous silicon, metal or metal-free phthalocyanine, cyanine, anthracene, bisazo compounds, pyrene, perylene, Examples thereof include various organic materials such as pyrylium salt, thiapyrylium salt, polyvinylcarbazole, and squarylium pigment. In addition, these charge generating substances may be used alone or in combination of two or more.

In the multi-layer type electrophotographic photoreceptor, the charge generation layer has at least a charge generation substance, and the charge generation layer is formed on the substrate or the charge transport layer, which is the base of the charge generation layer, by vacuum deposition, sputtering or the like. It can be obtained by forming a layer of a generating substance or forming a layer formed by binding a charge generating substance using a binder resin on a substrate or a charge transport layer which is an underlayer thereof. As a method for forming the charge generation layer when using a binder resin,
Although various methods such as a known method can be used, usually, a method in which a coating liquid in which a charge generating substance is dispersed or dissolved in a suitable solvent together with a binder resin is applied on a base substrate and dried is preferable. Used for.

The binder resin in the charge generation layer of the laminated electrophotographic photoreceptor is not particularly limited, and known binder resins can be used. For example, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, styrene-acrylonitrile copolymer, polycarbonate, polyamide, polyarylate, polyester, polyketone. ,
Thermoplastic resins such as polyacrylamide, butyral resin and ABS resin, and thermosetting resins such as polyurethane, epoxy resin and phenol resin can be used.
The above-mentioned polycarbonate can also be used as the binder resin in this charge generation layer.

Examples of the charge-transporting substances include conventionally used electron-transporting substances and hole-transporting substances. Examples of the electron-transporting substances include 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-Trinitrothioxanthone and 3,5-dimethyl-
Examples thereof include electron withdrawing substances such as diphenoquinone derivatives such as 3 ′, 5′-di-tert-butyl-4 ′, 4′-diphenoquinone, and polymer substances thereof. In addition,
These may be used alone or in a mixture of two or more.

Examples of the hole-transporting substance include pyrene, N-ethylcarbazole, N-isopropylpropicarbazole, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole and N, N-diphenyl. Hydrazino-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-tetrahydroquinoline-6-carboxaldehyde-
Hydrazones such as 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- [lepidyl (2)]-3- (p-diethylaminostyryl) -5-
(P-Diethylaminophenyl) pyrazoline, 1- [6
-Methoxy-pyridyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl)
Pyrazoline, 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-p-diethylaminostyryl)-
Pyrazolines such as 5- (p-diethylaminophenyl) pyrazoline and spiropyrazoline, 2- (p-diethylaminostyryl) -δ-diethylaminobenzoxazole, 2- (p-diethylaminophenyl) -4- (p
-Oxazole compounds such as -dimethylaminophenyl) -5- (2-chlorophenyl) oxazole, 2- (p
-Diethylaminostyryl) -6-diethylaminobenzothiazole and other thiazole compounds, bis (4-diethylamino-2-methylphenyl) phenylmethane and other triarylmethane compounds, 1,1-bis (4-
Polyarylamines such as N, N-diethylamino-2-methylphenyl) heptane and 1,1,2,2-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'-bis (tert)
-Butylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (isobutylphenyl) benzidine,
Benzidine compounds such as N, N'-diphenyl-N, N'-bis (chlorophenyl) benzidine, or butadiene compounds, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly- 9-vinylphenyl anthracene, organic polysilane, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin and the like can be mentioned. These may be used alone or as a mixture of two or more.

In the present invention, as a solvent that can be used when producing a coating liquid for producing the photosensitive layer, the charge generation layer or the charge transport layer, benzene, toluene,
Aromatic solvents such as xylene, chlorobenzene and dichlorobenzene, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, alcohol solvents such as methanol, ethanol, propanol, isopropanol, methyl cellosolve and ethyl cellosolve, ethyl acetate, methyl acetate Ester solvents such as carbon tetrachloride,
A halogen-based solvent such as chloroform, methylene chloride, 1,2-dichloroethane, tetrachloroethane, 1,1,1,3,3,3-hexafluoroisopropanol,
Examples thereof include ether solvents such as tetrahydrofuran and dioxane, and acetonitrile, dimethylformamide, dimethylsulfoxide, diethylformamide, and the like, and these may be used alone or in combination of two or more.

The coating of each layer can be carried out using various known coating devices. For example, an applicator, spray coater, bar coater, tip coater, roll coater, dip coater, doctor plate and the like can be used. In the electrophotographic photoreceptor of the present invention, by using a specific polycarbonate for the photosensitive layer, the compatibility with the charge generating substance and the charge transporting substance and the affinity with the solvent are improved. The electrophotographic solution has excellent mechanical strength for the photosensitive layer, good adhesion between the photosensitive layer and the base, and no long-term electrophotography without the working solution gelling or the binder resin in the photosensitive layer crystallizing. The characteristics can be maintained, and it can be suitably used in various electrophotographic fields.

[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 evaluation items and evaluation methods for the electrophotographic photosensitive member of the present invention are shown below. (A) Stability of coating liquid The coating liquid was allowed to stand for 1 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 As an apparatus, an electrostatic charging tester manufactured by Kawaguchi Denki Seisakusho was used to perform corona discharge of -6 kV to obtain an initial surface potential (V
₀ ) The residual potential (V _R ) and half-exposure dose (E _1/2 ) after light irradiation for 5 seconds were measured. (D) Abrasion resistance Using a Suga abrasion tester manufactured by Suga Testing Instruments Co., Ltd., 200 g
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 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 the three-necked flask, sodium hydroxide 68.03 g, the above formula (3)
27.52 g of the dihydric phenol shown in p-tert-
Butylphenol (0.25 g) was dissolved, and 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. After that, the polycondensation reaction is terminated by adding acetic acid, and washing is repeated with water until the aqueous phase becomes neutral.After the washing is completed, the organic phase and the aqueous phase are separated, and the organic phase is stirred in methanol. Was slowly added to precipitate the polycarbonate. Further, by filtering and drying, 30 g of a polycarbonate containing an aliphatic ring as a structural unit was obtained. When the inherent viscosity of the obtained polycarbonate was measured at 25 ° C. using a tetrachloroethane solvent, it was 0.720.

Example 2 27.14 g of dihydric phenol represented by the formula (3), pt
Polycarbonate was obtained in the same manner as in Example 1 except that 0.63 g of ert-butylphenol and 67.21 g of sodium hydroxide were used. The inherent viscosity of this polycarbonate was 0.488.

Example 3 26.89 g of the dihydric phenol represented by the formula (3), pt
A polycarbonate was obtained in the same manner as in Example 1 except that 0.87 g of ert-butylphenol and 66.67 g of sodium hydroxide were used. The inherent viscosity of this polycarbonate was 0.295.

Example 4 9.12 g of dihydric phenol represented by the formula (3), 2,2-
Bis (4-hydroxyphenyl) propane 14.99
Polycarbonate was obtained in the same manner as in Example 1 except that g, p-tert-butylphenol 0.70 g and sodium hydroxide 29.05 g were used. The inherent viscosity of this polycarbonate was 0.662.

Example 5 15.67 g of dihydric phenol represented by the formula (3), 2,2
-Bis (4-hydroxyphenyl) propane 11.03
g, p-tert-butylphenol 0.73 g, and sodium hydroxide 43.57 g were used to obtain a polycarbonate in the same manner as in Example 1. The inherent viscosity of this polycarbonate was 0.574.

Example 6 20.66 g of dihydric phenol represented by the formula (3), 2,2
-Bis (4-hydroxyphenyl) propane 6.23
Polycarbonate was obtained in the same manner as in Example 1 except that g, p-tert-butylphenol (0.68 g) and sodium hydroxide (53.85 g) were used. The inherent viscosity of this polycarbonate was 0.530.

Example 7 14.99 g of dihydric phenol represented by the formula (3), 2,2
-Bis (2-methyl-4-hydroxyphenyl) propane 11.85 g, p-tert-butylphenol 0.
A polycarbonate was obtained in the same manner as in Example 1 except that 69 g and 41.68 g of sodium hydroxide were used. The inherent viscosity of this polycarbonate was 0.542.

Example 8 14.72 g of dihydric phenol represented by the formula (3), 1,1
-Bis (4-hydroxyphenyl) cyclohexane 1
2.18 g, p-tert-butylphenol 0.68
Polycarbonate was obtained in the same manner as in Example 1 except that 42.02 g of sodium hydroxide was used. The inherent viscosity of this polycarbonate was 0.496.

Comparative Example 1 A polycarbonate was obtained in the same manner as in Example 1 except that 27.77 g of the dihydric phenol represented by the formula (3) and 68.57 g of sodium hydroxide were used. The inherent viscosity of this polycarbonate was 1.150.

Comparative Example 2 26.54 g of dihydric phenol represented by the formula (3), pt
Polycarbonate was obtained in the same manner as in Example 1 except that 1.23 g of ert-butylphenol and 65.92 g of sodium hydroxide were used. The inherent viscosity of this sample was 0.203.

Comparative Example 3 3.16 g of the dihydric phenol represented by the formula (3), 2,2-
Bis (4-hydroxyphenyl) propane 20.00
g, p-tert-butylphenol 0.73 g, and sodium hydroxide 16.46 g were used to obtain a polycarbonate in the same manner as in Example 1. The inherent viscosity of this sample was 0.687.

Comparative Example 4 2,2-bis (4-hydroxyphenyl) propane 2
6.09 g, p-tert-butylphenol 0.86
Polycarbonate was obtained in the same manner as in Example 1 except that 11.26 g of sodium hydroxide was used. The inherent viscosity of this polycarbonate was 0.702.

Comparative Example 5 2,2-bis (2-methyl-4-hydroxyphenyl)
A polycarbonate was obtained in the same manner as in Example 1 except that 26.47 g of propane, 0.78 g of p-tert-butylphenol and 10.17 g of sodium hydroxide were used. The inherent viscosity of this sample was 0.684.

Comparative Example 6 27.06 g of 1,1-bis (4-hydroxyphenyl) cyclohexane, p-tert-butylphenol.
Polycarbonate was obtained in the same manner as in Example 1 except that 76 g and 12.36 g of sodium hydroxide were used. The inherent viscosity of this polycarbonate was 0.512. Using the polycarbonates synthesized in the above Examples 1 to 8 and Comparative Examples 1 to 7, as the charge transporting substance, the compound represented by the formula (19)
Using a compound with the structure shown in

[0048]

[Chemical 8]

A solution of polycarbonate: charge-transporting substance: methylene chloride = 1: 1: 8 (weight ratio) was prepared as a coating solution, and such coating solution was formed on an aluminum conductive substrate. About 0.1% of titanium phthalocyanine.
A 5 μm charge generation layer was coated by a dip coating method and dried, and then a 20 μm charge transport layer was provided to produce a laminated electrophotographic photoreceptor.

The proportion of dihydric phenol in the polycarbonate, the amount of p-tert-butylphenol (PTBP) added, and ηinh. Are shown in Table 1, and the presence or absence of gelation of the coating liquid and the presence or absence of crystallization during coating are shown in Table 2. Table 3 shows the initial surface potential (V ₀ ), the residual potential (V _R ), the half-exposure amount (E _1/2 ) after light irradiation for 5 seconds, and the result of the abrasion amount of the charge transport layer in the abrasion resistance test. Is shown in Table 4.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

[0055]

Since the electrophotographic photosensitive member of the present invention is constituted as described above, the coating liquid may gel or the binder resin in the photosensitive layer may be crystallized during the preparation of the photosensitive layer. There is no. Further, the adhesion between the photosensitive layer and the base is good, and the photosensitive layer has excellent mechanical strength and good printing durability, so that excellent electrophotographic characteristics can be maintained for a long period of time.

Claims (1)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the binder resin forming the photosensitive layer is a polycarbonate having structural units represented by formulas (1) and (2). , These equations (1) and (2)
The molar fraction of the structural unit represented by is 0.2 ≦ [(1) /
{(1) + (2)}] ≦ 1.0, and an inherent viscosity (ηinh .: tetrachloroethane as a solvent, a binder resin concentration of 1.0 g / dl, and 25 ° C.
The electrophotographic photoreceptor is characterized in that it is 0.2 to 1.0. [Chemical 1] [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,
R _{3 to} R ₁₂ are each independently selected from a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, and X is 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 It is selected from the group consisting of phenylalkylidene groups. ] [Chemical 2] [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,
Y is selected from the group consisting of a single bond, 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. ]