JPH03273256A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent white blooming (gelation) of a coating fluid and to enhance surface hardness and printing resistance by incorporating a polycarbonate resin specified in chemical structure and reduced viscosity as a binder resin in a photosensitive layer, especially, in an electric charge generating layer for composing the photosensitive layer. CONSTITUTION:The photosensitive layer contains the polycarbonate resin having repeating units each represented by formulae I and II in a I to II molar ratio of 1-0.05:1, and the polycarbonate resin to be used as the binder resin has a reduced viscosity of 0.6-2.0 dl/g in a methylene chloride solution of 0.5 g polycarbonate/dl at 20 deg.C. In formulae I and II, each of R<1> and R<2> is 1-6 C alkyl; X is a simple bond, -O-, -S-, -SO-, -SO2-, or the like; each of s and (t) is an integer of 1-4; each of R<3> and R<4> is H, halogen, 5-7 C cycloalkyl, or the like; Y is same as X; and each of (p) and (q) is an integer of 0-4, thus permitting white blooming of the coating fluid to be prevented surface hardness and printing resistance to be enhanced.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, the present invention relates to an electrophotographic photoreceptor, and more specifically, the coating solution does not whiten (gel) during the production of the electrophotographic photoreceptor, and the surface hardness is improved. The present invention relates to an electrophotographic photoreceptor that has high hardness and excellent rigidity and can be suitably used in various electrophotographic fields.

[Conventional technology]

The mainstream of recent electrophotographic photoreceptors is a laminated organic electrophotographic photoreceptor in which the photosensitive layer has at least two layers: a charge generation layer that generates charges upon exposure, and a charge transport layer that transports charges. ing. In this laminated type organic photoreceptor, a polycarbonate resin made from bisphenol A is widely used as a binder resin for the charge transport layer (Japanese Patent Publication No. 21792/1982).

Polycarbonate resin made from bisphenol A has good compatibility with cargo transport materials, so when it is produced as a photoreceptor, it has good electrical properties and relatively high mechanical strength.

However, it has been found that when a charge transport layer is formed using a polycarbonate resin made from sphenol A as a binder resin, the following problems occur.

■ When applying the charge transport layer during photoreceptor production,
Depending on the solvent used, the coating solution may become white (gelled) or
The charge transport layer may easily crystallize. In these areas where whitening or crystallization has occurred, there is no light attenuation, and the charge remains as a residual potential, which appears as a defect in image quality.

■ Made with polycarbonate resin made from bisphenol A! ? ;j@Feeding layer has the disadvantage that it wears out due to insufficient surface hardness, resulting in short printing life.

(Problem to be solved by the invention) The present invention has been made based on the above circumstances.

An object of the present invention is to solve the above-mentioned problems observed in conventional electrophotographic photoreceptors that use polycarbonate resin made from bisphenol A as a binder resin for the charge transport layer, and It is an object of the present invention to provide an electrophotographic photoreceptor which is excellent in practical use, has improved surface hardness, improved printing durability, and maintains electrophotographic properties without whitening (gelation) of the liquid.

[Means for Solving the Problems] As a result of extensive research in order to solve the above-mentioned problems, the present inventors have found that a specific chemical structure is incorporated as a binder resin in the photosensitive layer, particularly in the charge transport layer constituting the photosensitive layer. An electrophotographic photoreceptor using a polycarbonate resin having a certain reduced viscosity and a specific reduced viscosity does not suffer from the above-mentioned problems found in conventional electrophotographic photoreceptors using a polycarbonate resin made from bisphenol A as a binder resin. They have discovered that there are no spots, the coating solution does not whiten (gel) during the production of photoreceptors, the surface hardness is improved, the printing durability is improved, and the electrophotographic properties are maintained. Based on this knowledge, we have completed the present invention.

That is, the present invention provides an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, in which the photosensitive layer has the following general formula [wherein R1 and R2 in formula (1) represent an alkyl group having 1 to 6 carbon atoms]. , X is a single bond, -O--S--5O-1
-SOz--(CH2)- (where r represents an atom of 2 to 0, an alkyl group of 6 to 6 carbon atoms, an aryl group of 6 to 12 carbon atoms, or -CF), and t is 1~
Represents an integer of 4. ] and the following general formula 0 (wherein R3 and R' in formula (II) represent a hydrogen atom, a halogen atom, a cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and Y is the above-mentioned X in formula (1)
, and P and q represent integers of O to 4. )
The repeating unit represented by is expressed by the composition ratio of formula (1) ((1:
l/((1)+(I[])) is 1- in molar ratio
0.05 and whose reduced viscosity at 20°C of a solution with a concentration of 0.5 g/- using methylene chloride as a solvent is 0.6 to 2.0 di/g as a binder resin. The present invention provides an electrophotographic photoreceptor characterized in that it can be used as an electrophotographic photoreceptor.

The chemical structural characteristics of the polycarbonate resin of the present invention are as follows:
It is obtained by polycondensation using bisphenols having an alkyl substituent on the benzene ring as a raw material, and its reduced viscosity, which is a measure of its molecular weight, is in a specific range.

When such a polycarbonate resin is used as a binder resin for an electrophotographic photoreceptor, the properties required for the binder resin are improved. In particular, there is no whitening phenomenon in the gap when the charge transport material and binder resin are dissolved in a solvent and applied to the conductive substrate, and the surface hardness of the photosensitive layer after coating increases, resulting in a long printing life. This has the practical advantage of allowing the electrophotographic photoreceptor to be used for a long period of time.

Specific examples of each of R' and R2 include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, 1-methylpropyl group, 2-methylpropyl group, tert-butyl group. , n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, and the like.

Note that R1 and R2 may be the same group or different groups.

Further, when the repeating unit represented by formula [I] has a plurality of R1 groups, these R1 groups may be the same group or may be different, and it has a plurality of F12 groups. In this case, these R2 groups may be the same group or different.

The above S and t each independently represent an integer of 1 to 4.

Specific examples of the 4CH2,+T- group include a methylene group, a dimethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, an octamethylene group, and a decamethylene group.

Among these, dimethylene group and the like are particularly preferred.

Examples include 1-cyclopentylidene group, 1.1-cyclohexylidene group, and 1.1-cyclooctylidene group. Among these, 1°1-cyclohexylidene group is particularly preferred.

S Specific example 6 of each of R5 and R6 in the above -C-. Methylpropyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group,
isohexyl group, phenyl group, tolyl group, xylyl group,
Examples include trimethylphenyl group, ethyltuunyl group, naphthyl group, methylnaphthyl group, biphenylyl group, -CFY, and the like. Among these, methyl group and the like are particularly preferred. In addition, R5 and door may be the same group or may be different groups.

Specific examples of each of R3 and R4 include, for example, a hydrogen atom, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a phenyl group, a tolyl group, a xylyl group,
Examples include trimethylphenyl group, ethylphenyl group, naphthyl group, methylnaphthyl group, and biphenylyl group.

Note that R) and R4 may be the same group or different groups.

Further, the repeating unit represented by formula (II) is a plurality of R3
In the case of having a plurality of R4 groups, these R'' groups may be the same group or different groups, and in the case of having a plurality of R4 groups, these R1 groups may be the same group or Well, they can be different.

The above p and q each independently represent an integer of O to 4, and the case where p=q=o is particularly preferred.

A polycarbonate consisting of a repeating unit represented by the above-mentioned general 2N) (hereinafter, this may be abbreviated as polycarbonate (1)). ) is, for example, one or more dihydric phenols represented by the following general formula (wherein X, R', R'', S and t each represent the same meaning as above). [Hereinafter, these may be abbreviated as dihydric phenols (bi)] and a carbonate precursor such as phosgene are condensed and polymerized in a suitable neutral polar solvent in the presence of a suitable acid binder. Alternatively, it can be obtained by a method such as a transesterification reaction between a dihydric phenol (1') and a bisaryl carbonate.

Further, a polycarbonate copolymer consisting of a repeating unit represented by the general formula (1) and a repeating unit represented by the general formula (II) [hereinafter may be abbreviated as polycarbonate copolymer (II)] . ], 11 types are 2
One or more of the dihydric phenols (1') and one or more of the following general formulas (wherein Y, R'', R4, P and q each have the same meanings as above). ) [Hereinafter, this will be referred to as dihydric phenol II
It may be abbreviated as (II'). ] and a carbonate precursor such as phosgene in the presence of a suitable acid binder in a suitable solvent, or alternatively, these dihydric phenols (1') and (■') and bisaryl carbonate It can be obtained by a method such as a transesterification reaction with.

Said dihydric phenol! Specific examples of (+') include 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)butane, 3゜3- bis(3-methyl-4
-hydroxyphenyl)pentane, l,1-bis(3-
Methyl-4-hydroxyphenyl)cyclohexane, 1
．． 1-bis(3-methyl-4-hydroxyphenyl)cyclopentane, 1,1-bis(3-methyl-4-hydroxyphenyl)cycloheptane, 2,2-bis(2-methyl-4-hydroxyphenyl) Propane, 2,2-bis(2-methyl-3-methyl-4-hydroxyphenyl)propane, 2,2-bis(2-methyl-4-hydroxy-5-methylphenyl)propane, 2,2-bis( 3
-ethyl-4-hydroxyphenyl)propane, 2,2
Bis(2-methyl-3-ethyl-4-hydroxyphenyl)propane, 2,2-bis(3-isopropyl-4-
hydroxyphenyl)propane, 2゜2-bis(2-methyl-4-hydroxy-5-isopropylphenyl)propane, bis(3-methyl-4-hydroxyphenyl)
Methane, 1.1-bis(3-methyl-4-hydroxyphenyl)ethane, 1.2-bis(3-methyl-4-hydroxyphenyl)ethane, 1.3-bis(3-methyl-
4-hydroxyphenyl)propane, ■, 4-bis(3
-Methyl-4-hydroxyphenyl)butane, 1-phenyl-1,1-bis(3-methyl-4-hydroxyphenyl)ethane, 2-(3methyl-4-hydroxyphenyl)-2-(4-hydroxyphenyl) ) propane, 2-
(3-methyl-4-hydroxyphenyl)-2-(3
-ethyl-4-hydroxyphenyl)propane, 3.3
-dimethyl-4,4'-dihydroxybiphenyl, bis(3-methyl-4-hydroxyphenyl) ether, bis(3-methyl-4-hydroxyphenyl) sulfide, bis(3-methyl-4-hydroxyphenyl) sulfone , 2,2-bis(3-methyl-4-hydroxyphenyl)hexafluoropropane, and the like.

Among these, 2,2-bis(3-methyl-4-
hydroxyphenyl)propane, 1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane, 3.
3'-dimethyl-4,4'-dihydroxybiphenyl and the like are preferably used.

Further, as specific examples of the dihydric phenols (■'), for example, bis(4-hydroxyphenyl)methane,
, 1-bis(4-hydroxyphenyl)ethane, 1,2
-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane,
-hydroxyphenyl)octane, 4,4-bis(4-
hydroxyphenyl)hebutane, 4,4'-dihydroxytetraphenylmethane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 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, 4,4'-dihydroxybiphenyl, bis(3-chloro-4-hydroxyphenyl)
Methane, bis(3,5-,;bromo-4-hydroxyphenyl)methane, 2,2bis(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, 3゜3'-difluoro-4,
4'-dihydroxybiphenyl, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-phenyl) -4-hydroxyphenyl)propane, 11-bis(3-phenyl-4-hydroxyphenyl)cyclohexane, bis(
Examples include 3-phenyl-4-hydroxyphenyl) sulfone.

Among these, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxytetraphenylmethane, 1-phenyl-1°1-bis(4-hydroquinphenyl)ethane, bis(4- hydroxyphenyl) sulfone, 1,1-bis(4-hydroxyphenyl)
Cyclohexane, 4,4'-dihydroxybiphenyl,
2,2-bis(3-phenyl-4-hydroxyphenyl)propane and the like are preferably used.

As the acid binder, various known ones can be used, and specific examples include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, organic bases such as pyridine, or mixtures thereof. used.

Further, as the solvent, for example, methylene chloride, chlorobenzene, xolene, etc. are used. Furthermore, in order to accelerate the polycondensation reaction, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used, and in order to adjust the degree of polymerization, a catalyst such as pt-butylphenol or phenylphenol is used. It is desirable to carry out the reaction by adding a molecular weight regulator. Further, if desired, a small amount of an antioxidant such as sodium gnitite or hydrosulfide may be added. The reaction is usually carried out at 0 to 150°C2, preferably at 5 to 150°C.
It is carried out at a temperature in the range of 40°C. The reaction time depends on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. Also, during the reaction, p of the reaction system
It is desirable to maintain H at 10 or more.

On the other hand, in the latter transesterification method, the dihydric phenol compound and bisaryl carbonate are mixed,
The reaction is carried out at elevated temperature under reduced pressure.

The reaction is usually carried out at 150 to 350°C, preferably 200 to 30°C.
The reaction is carried out at a temperature in the range of 0.degree. C., and the degree of vacuum is preferably at a final pressure of less than 1.degree. Hg, so that the phenols derived from the bisaryl carbonate produced by the transesterification reaction are distilled out of the system. The reaction time depends on the reaction temperature, degree of pressure reduction, etc., but is usually about 1 to 4 hours.

The reaction is preferably carried out under an inert gas atmosphere such as nitrogen or argon, and the reaction may be carried out by adding the above-mentioned molecular weight regulator, antioxidant, etc., if desired.

The polycarbonate (1) and the polycarbonate copolymer (II) used in the photosensitive layer of the electrophotographic photoreceptor of the present invention each have a concentration of 0 using methylene chloride as a solvent.
．． The reduced viscosity (7751)/C) measured at 20° C. in a solution of 5 g/di is within the range of 0.6 to 2.0 a/g. Preferably, those within the range of 0.7 to 1.5d17g can be suitably used. Reduced viscosity is 0
．． If it is less than 6 a/g, the mechanical strength, especially the surface hardness, will be insufficient and the photoreceptor will wear out, resulting in a short practical printing life. 10d1
/g, the solution viscosity increases, making it difficult to manufacture photoreceptors by solution coating.

The above polycarbonate) N) may be a homopolymer consisting of one type of repeating unit (U-1) represented by the above formula N), or may be a homopolymer consisting of two or more types of repeating units (U-1) in an arbitrary ratio.
A copolymer consisting of 1) may also be used. These may be used alone or in combination of two or more in any proportion, such as a mixture.

The polycarbonate copolymer (II) is a copolymer consisting of one or more types of (U-I) and one or more types of repeating units (U-■) represented by the formula (n). Polymers can be used.

The ratio of the repeating units (U-1) and (LJ-11) in the polycarbonate copolymer (Il) is (
U-1) is set to 100 to 5 mol%. If it is less than 5 mol %, the stability of the coating liquid will not be sufficient and the surface hardness will not be sufficient. These polycarbonate copolymers (n) may be used alone, or two or more may be used in combination as a mixture or the like in any proportion.

Furthermore, two or more types of the above polycarbonate (I) and polycarbonate copolymer (If) can also be used together as a mixture or the like in any proportion.

Furthermore, the polycarbonate (I) and/or polycarbonate copolymer (II) may be used in combination with other known binder resins such as polycarbonate or separately, as long as it does not impede the purpose of the present invention. You can also.

The electrophotographic photoreceptor of the present invention has a photosensitive layer having a charge generation layer and a charge transport layer on a conductive substrate, and a charge transport layer 1 may be laminated on the charge ordering layer. Often, a charge generation layer may be laminated on the charge transport layer. In addition, a conductive or insulating protective film may be formed on the surface layer if necessary, and an adhesive layer to improve adhesion between each layer or a pronging layer that serves as a charge blocking layer. An intermediate layer such as the like may also be formed.

The electrophotographic photoreceptor of the present invention uses at least the polycarbonate (■) or polycarbonate copolymer (It) as a binder resin in the photosensitive layer, preferably in the charge transport layer in the photosensitive layer. It is something.

As the conductive substrate material used in the electrophotographic photoreceptor of the present invention, various known materials can be used. Specifically, for example, aluminum, brass, copper, nickel, steel, etc. Metal plates, metal sheets, blank sheets that are coated with conductive substances such as aluminum, nickel, chromium, palladium, graphite, etc. by vapor deposition, sputtering, coating, etc. to make them conductive, or gumis, plastics. board,
A substrate made of cloth, paper, etc. that has been subjected to conductive treatment can be used.

The charge generation layer has at least a charge generation material, and the charge generation layer is obtained by forming a layer on the underlying substrate by binding the regeneration material of 1 with a binder resin. be able to. Various methods such as known methods can be used to form the charge generation layer, but usually, for example, a coating solution in which the 'fgL charge generation material is dispersed or dissolved in a suitable solvent together with a binder resin is mixed with a predetermined coating solution. A method of applying the coating onto a substrate serving as a base and drying it can be suitably used.

As the charge generation material in the charge generation layer, various known materials can be used, and specifically,
For example, selenium units such as amorphous selenium and trigonal selenium,
Selenium alloys such as selenium-tellurium, selenium compounds such as As and Se3, or selenium-containing &Il paraboloids, inorganic materials consisting of group Ⅰ and group Ⅰ elements such as zinc oxide and Cd5-3e, and oxides such as titanium oxide. various inorganic materials such as silicon-based semiconductors, amorphous silicon and other silicon-based materials, metal or non-metallic phthalocyanines, cyanines, anthracene, pyrene, perylene, biryllium salts, thiavilylim salts, polyvinylcarbadules, squareium pigments, etc. Examples include organic materials.

Note that these may be used alone, or
They can also be used in combination by mixing two or more types.

The binder resin in the charge generation layer is not particularly limited, and various known ones can be used. Specifically, for example, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl Thermoplastic resins such as acecool, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, polyester, thermosetting resins such as polyurethane, epoxy resin, phenolic resin, etc. can be used. can.

In addition, as the binder resin in the charge generation layer,
It is also possible to use the polycarbonate (I) or polycarbonate copolymer (It).

Note that these binder resins may be used alone or in combination of two or more as a mixture.

The charge transport layer can be obtained by forming a layer formed by binding a charge transport material with a binder resin on the underlying substrate.

Various known methods can be used to form this charge transport layer, but usually, for example, a coating liquid in which a charge transport material is dispersed or dissolved in a suitable solvent together with a binder resin is used. A method in which the coating is applied onto a substrate serving as a predetermined base and dried can be suitably used.

The electrophotographic photoreceptor of the present invention uses at least the polycarbonate (1) or the polycarbonate copolymer (II) as a binder resin in the photosensitive layer, and does not necessarily contain the polycarbonate (1) or the polycarbonate copolymer (II) as the binder resin in the charge transport layer. Although not limited to those using polycarbonate (1) or polycarbonate copolymer (It), in order to fully exhibit the effects of the present invention, it is necessary to use the polycarbonate N as a binder resin in the charge transport layer. ) or polycarbonate copolymer (■).

As the charge transport material in the charge transport layer, any of the conventionally used electron transport substances and hole qa transport substances can be used.

Specific examples of electron-transporting substances include chloroanil, furoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-dolinitro-9-fluorenone, and 2,4,5,7-tetranitro-9-tetrafluorenone. , 2.4.7-dolinitro-9-dicyanomethylenefluorenone, 2.4.5.7-titranitroxanthone, 2.4.9-1linitrothioxanthone and other electron-withdrawing substances, and these electron-withdrawing substances in polymers. There are some things that have changed. In addition, these may be used alone,
Alternatively, two or more types can be mixed and used together.

Examples of hole transport substances include pyrene, N-ethylcarbazole, N-isobrovir rubadur, 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-diphenylhydrazino, P-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, P-pyrrolidinobenzaldehyde -N,
N-diphenylhydrazone, 1,3,3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazino, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, etc. W
+, 2,5-bis(P-diethylaminophenyl)-1
, 3,4-oxadiazole, l-phenyl-3-(p
-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(2))-3
-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[Levidil (2)
]-3-(p-diethylaminostyryl)-5-(P-
diethylaminophenyl)pyrazoline, 1-[6-medoxybilidyl(2))-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)viraprine, 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) birapurine, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl) hirazoline, 1-phenyl-3(α-
benzyl-p-diethylaminostyryl)-5-(p-
pyrazolines such as diethylaminophenyl)pyrazoline and spiropyrazoline, 2-(p-diethylaminostyryl)-δ-diethylaminobenzoxazole, 2-(
Oxazole compounds such as P-diethylaminophenyl)-4-(p-dimethylaminophenyl)5-(2-chlorophenyl)oxazole, thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole , bis(4-diethylamino-2
-methylphenyl)-phenylmethane and other triarylmethane compounds, 1.1-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1.2.
Polyaryl short molecules such as 2-tetrakis(4-N,N-dimethylamino-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''-'; phenyl N, N'
-bis(sec-butylphenyl)benzidine, N, N'
-diphenyl-N,N'-bis(tertiary butylphenyl)benzidine, N,N'diphenyl-N,N'-bis(
benzidine compounds such as (chlorophenyl) benzidine,
Triphenylamine, poly N-vinyl carhadur,
Examples include polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin.

Note that these may be used alone, or
Two or more types may be mixed and used in combination.

Specific examples of the solvent used in forming the charge generation layer and the charge transport layer include penzene, toluene,
Aromatic heating media such as xylene and chlorobenzene, ketones such as acetone, methyl ethyl ketone, and cyclohexanone,
Alcohols such as methanol, ethanol and isopropanol, esters such as ethyl acetate and ethyl cellosolve, halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, chloroform, dichloromethane and tetrachloroethane, ethers such as tetrahydrofuran and dioxane, dimethyl Formamide, dimethyl sulfoxide, diethyl formamide, etc. can be mentioned.

These solvents may be used alone or in combination of two or more as a mixed solvent.

Coating of each layer can be performed using various coating devices such as those known in the art. Specifically, for example, an applicator,
This can be carried out using a spray coater, a bar coater, a dip coater, a roll coater, a doctor blade, or the like.

The electrophotographic photoreceptor of the present invention does not cause whitening (gelation) of the coating solution or solvent cracks during its production, has high surface hardness, and has excellent printing durability. It is a photoreceptor and can be suitably used in various fields of electrophotography.

〔Example〕

Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

Example 1 65.5 g (0,256 mol) of 2,2-bis(3-methyl-4-hydroxyphenyl)propane as a monomer
, 550ad of 8% NaOH aqueous solution, 40ad of methylene chloride
0j! ! ! , 0.8 g of p-tert-butylphenol as a molecular weight regulator and a 10% triethylamine aqueous solution 3 as a catalyst were condensed by blowing phosgene gas into the reactor for 10 minutes with vigorous stirring in a reactor equipped with a baffle plate. After the polymerization was completed, the organic phase was diluted with methylene chloride IE, washed in this order with water, diluted hydrochloric acid, and water, and then poured into methanol to obtain polycarbonate.

This polymer has a concentration of 0°5g in methylene chloride as a solvent.
/d1 solution at 20°C reduced viscosity (η8°/c
) was 0.96 dl/g, and 'rg was 123°C.

It was confirmed by H-NMR spectrum analysis that it consisted of the following repeating units.

As a charge transport material, 50% of the following hydrazone compound was used.
A 10% by weight solution of the above polycarbonate containing % by weight in tetrahydrofuran was prepared.

A laminated electrophotographic photoreceptor was manufactured by providing a charge transport layer.

The charge transport layer did not crystallize during coating. In addition, the electrophotographic characteristics were measured using an electrostatic charging tester EPA-8100.
(Kawaguchi Electric Seisakusho type). -6 kV corona discharge, initial surface potential (vo), light irradiation (1
Residual potential (V, ) after 0 Lux), half-decreased exposure amount (E, /
-) was measured, and it was shown that it was equivalent to the conventional product (Comparative Example 1.2) and was at a sufficient practical level. The results are shown in Table 1, and the surface hardness (pencil hardness; JIS K-5400) of this charge transport layer was B.

Even when the coating solution 20 was left for one month, no cloudiness or gel formation was observed. Using aluminum as the conductive substrate,
Approximately 0.5 μm using oxotitanium phthalocyanine
This coating solution was applied by dip coating onto the charge generating layer of Example 2, and after drying, 75.8 g of 1.1-bis(3-methyl-4-hydroxyphenyl)cyclohexane (0 ,25
A polycarbonate polymer consisting of the following repeating units was obtained in the same manner as in Example 1 except that 6 mol) was used.

This polymer has a reduced viscosity [η□/c) of 0.79 di
/g, Tg was 145°C.

Using this polymer, a laminated electrophotographic photoreceptor was produced in the same manner as in Example 1. The evaluation results regarding the stability of the coating solution, crystallization during coating, electrophotographic properties, and surface hardness were all the same as in Example 1.

Example 3 51.2 g (0.20 mol) of 2.2-bis(3-methyl-4-hydroxyphenyl)propane and 13 mol of 2.2-bis(4-hydroxyphenyl)propane as monomers
A polycarbonate copolymer consisting of the following repeating units was obtained in the same manner as in Example 1 except that g (0,057 mol) was used. This copolymer has a reduced viscosity (ηap/c
) was 0.87 d1/g, and Tg was 129°C.

A laminated electrophotographic photoreceptor was produced in the same manner as in Example 1 using Copolymer No. 20. The evaluation results regarding coating liquid stability, crystallization during coating, electrophotographic properties, and surface hardness are as follows:
All were similar to Example 1. Comparative Example 1 Polycarbonate using commercially available 2.2-bis(4-hydroquinphenyl)propane (bisphenol A) (reduced viscosity [ηsp/c) = 0.78 d1 /g, Tg
In the same manner as in Example 1, an attempt was made to produce a laminated electrophotographic photoreceptor.

As a result, the coating solution became cloudy on the second day and a gel was generated.

Further, a portion of the charge transport layer during coating was crystallized (whitened). Further, the surface hardness of this charge transport layer was 4B. The results of the photographic characteristics are shown in Table 1.

Table 1 Comparative Example 2 2,2-bis(3-methyl-4-hydroxyphenyl)propane 65.5 g (0,256 mol) as a monomer
A polycarbonate (reduced viscosity (η, , /c) =0. 53a/g, Tg”
123°C) was obtained. Using this polymer, Example 1
A laminated electrophotographic photoreceptor was produced in the same manner as described above. The evaluation results for stability after coating, crystallization during coating, and electrophotographic properties were all the same as in Example 1. Also,
The surface hardness of this charge transport layer was 3B.

〔Effect of the invention〕

According to the present invention, polycarbonate having a specific structure is used as a binder resin in the photosensitive layer, particularly in the electron transport layer of the photosensitive layer, so that the coating solution becomes white (gelled) during the production of the electrophotographic photoreceptor. It is possible to provide an electrophotographic photoreceptor that is excellent in practical use, has improved surface hardness, improved rigidity, and maintains electrophotographic properties without causing any damage, and its industrial value is extremely large.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the photosensitive layer contains the following general formula ▲ mathematical formula, chemical formula, table, etc. ▼ [However, in formula [I] R^1 and R^2 have 1 or more carbon atoms
6 represents an alkyl group, X is a single bond, -O-, -S-,
-SO-, -SO_2-, -(CH_2)_r- (where r represents an integer from 2 to 10), ▲Mathematical formulas, chemical formulas, tables, etc.▼(where n represents an integer from 4 to 10). ) or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R^5 and R^6
is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and 6 to 1 carbon atoms.
2 or -CF_3. ), and s and t represent integers of 1 to 4. ] and the following general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (However, R^3 and R^4 in formula [II] are hydrogen atoms,
It represents a halogen atom, a cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and Y represents the above formula [I]
represents the same meaning as X, and p and q represent integers of 0 to 4. ) is expressed as the repeating unit represented by the composition ratio {
[I]/([I]+[II])} is 1 to 1 in molar ratio
0.05, and the reduced viscosity of a solution of methylene chloride as a solvent with a concentration of 0.5 g/dl at 20° C. is 0.6 to 2.0 dl/g as the binder resin. An electrophotographic photoreceptor characterized in that it is used.