JPH0342667A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent the degradation in electrostatic chargeability by repetitive use and to provide a longer life and higher reliability by using a specific compd. as a charge generating material and incorporating another compd. into a photosensitive layer. CONSTITUTION:The compd. expressed by formula I is used as the charge generating material and the compd. expressed by formula II is incorporated into the photosensitive layer. In the formula I, A denotes a residual coupler group having a phenolic OH group. In the formula II, R1 to R4 denote a hydrogen atom, hydroxyl group, alkoxy group or alkyl group; at least one of R1 to R4 are a hydroxyl group. R5 and R6 denote a hydrogen atom, alkenyl group or alkyl group. The degradation in the electrostatic chargeability by the repetitive use is prevented and the longer life and the higher reliability are obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and particularly to an electrophotographic photoreceptor that has excellent charging stability even when used repeatedly over a long period of time. .

[Conventional technology]

Inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been conventionally known as photoconductive materials for electrophotographic photoreceptors. However, these inorganic materials do not necessarily satisfy the characteristics such as photosensitivity, thermal stability, and durability required for electrophotographic photoreceptors, as well as manufacturing conditions. For example, selenium tends to crystallize due to heat, dirt, etc., and its properties tend to deteriorate. In addition, it has drawbacks such as manufacturing cost, impact resistance, toxicity, and other issues that require careful handling.

Photoreceptors using cadmium sulfide have poor moisture resistance and durability, and also have problems such as toxicity. Zinc oxide also has the disadvantage of poor moisture resistance and durability.

For electrophotographic photoreceptors using these inorganic photoconductive materials,
Photoreceptors using organic photoconductive substances are being actively researched and developed because of their light weight, ease of film formation, manufacturing cost, and wide variation as organic compounds. For example, in the early days, there was a photoreceptor containing polyvinylcarbazole and 2,4,7-dolinitro-9-fluorenone described in Japanese Patent Publication No. 50-1.0496;
A photoreceptor in which polyvinylcarbazole is sensitized with a pyrylium salt dye or a photoreceptor mainly composed of a eutectic complex has been proposed, as described in Japanese Patent No. 8-25658. However, these photoreceptors do not have sufficient sensitivity and durability.

Therefore, in recent years, a functionally separated type photoreceptor in which a charge generation layer and a charge transport layer are separated has been proposed, and
A photoreceptor made of a combination of Chlordiane Blue and a Hi-Razone compound described in the above No. 1, and a bisazo compound as the charge generating substance, described in JP-A-53-1.33445, JP-A-54-21728, and JP-A-54-21728. Showa 54-228
34, as a charge transport material, JP-A-58-1
．． 98043 and those described in JP-A-58-1.99352 are known.

Even in these function-separated type photoreceptors, there has been an increasing demand for ozone resistance in recent years.

When a photoreceptor is actually used in a copying machine, the photoreceptor is exposed to ozone generated from a charger and is therefore subject to strong oxidation. In the case of organic photoreceptors in particular, this effect is large, and the constituent materials of the photosensitive layer gradually oxidize and decompose, resulting in
This results in deterioration in the performance and durability of the photoreceptor. As a countermeasure, JP-A No. 57-1.22444, JP-A No. 611.56052, JP-A-61-], ]56
], No. 31, it has been proposed to add an antioxidant to the photosensitive layer.

However, these proposals are insufficient to prevent the deterioration of chargeability due to repeated use of the photoreceptor.

[Problem to be solved by the invention]

An object of the present invention is to provide a photoreceptor with long life and high reliability, which prevents deterioration in chargeability due to repeated use of the photoreceptor.

[Means to solve the problem]

4- According to the present invention, in an electrophotographic photoreceptor in which a photosensitive layer containing a charge generating substance and a charge transporting substance is provided on a conductive support, a compound represented by the following general formula (I) is used as a charge generating substance. and the photosensitive layer has the following general formula (n):
An electrophotographic photoreceptor is provided, which is characterized by containing a compound represented by:

(In the formula, A represents a coupler residue having a phenolic OH group.) (In the formula, R, , R2, R3 and R4 represent a hydrogen atom, a hydroxyl group, an alkoxy group, or an alkyl group; however, R , , at least one of R2, R3 and R4 is a hydroxyl group), R5 and R6 represent a hydrogen atom, an alkenyl group or an alkyl group. ) The electrophotographic photoreceptor of the present invention uses a disazo pigment represented by the above general formula (1) as a charge generating substance and contains a compound represented by the above general formula (IT) in the photosensitive layer. Since deterioration in the chargeability of the photoreceptor due to use can be reliably suppressed, stable and clear copied images can be provided over a long period of time.

In the compound represented by the general formula (1) used in the present invention, examples of the coupler residue A include the following groups.

R3 'x' (wherein, X is a naphthalene ring fused with a benzene ring,
Represents a polycyclic aromatic ring selected from anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, and diphenylene sulfide ring, or a residue necessary to form a petero ring, and R3 and R4 are hydrogen atoms, substituted, and unsubstituted. It represents a group selected from substituted alkyl, aralkyl, aryl, and heterocyclic groups, or a cyclic amino group formed with the nitrogen atom to which R3 and R4 are bonded. ) (wherein, R5,
R6 represents a group selected from substituted and unsubstituted alkyl groups, aralkyl groups, and aryl groups. ) 11 (In the formula, ■ represents a divalent group of an aromatic hydrocarbon or a divalent group of a petro ring containing a nitrogen atom in the ring.) 7 (In the formula, R7TRRTRRNRIO is a hydrogen atom, a substituted,
Indicates a group selected from unsubstituted alkyl groups, aralkyl groups, aryl groups, and heterocyclic groups, or a residue that forms a 5- or 6-membered ring with the carbon atoms of R91R10, and this 5- or 6-membered ring is a fused aromatic ring. It may have a group ring.

Z is a naphthalene ring fused with a benzene ring,
Residues necessary to form a polycyclic aromatic ring or heterocycle selected from a helical ring, a carbazole ring, a benzcarbazole ring, a dibenzofuran ring, a benzonaphthofuran ring, and a diphenylene sulfide ring are shown. ) =7- Specific examples of the disazo pigment shown in the above-mentioned -formation (1) used in the present invention are shown below.

11 -12 15 5U311 u3h 1b- 19 20 Specific examples of the compound represented by the above-mentioned form (n) that can be used in the present invention include the following compounds.

Tocopherol (5,7,8 trimethyl docol) γ-
Tocopherol (7,8-dimethyltocol) δ-tocopherol (8-methyltocol) Among these, the use of α-tocopherol is particularly preferable from the viewpoint of the expression of effects. These compounds can be used alone or as a mixture of two or more.

Further, in the present invention, a charge transport substance is used together with a charge generation substance, and the charge transport substance includes a hole transport substance and an electron transport substance. Examples of the hole transport substance include compounds represented by the following general formulas (1) to (12).

1.

[In the formula, R1 represents a methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, R2 represents a methyl group, ethyl group, benzyl group, or phenyl group, and R
3 represents hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. [r9) [In the formula, Ar represents naphthalenes, anthracenes, styryl groups, and substituted products thereof, or pyridines, furans, and thiophenes, and R represents an alkyl group or a benzyl group. ] r3) K] [In the formula, R1 is an alkyl group, a benzyl group, a phenyl group,
Represents a naphthyl group, R2 represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms, a dialkylamino group, a dialkylamino group, or a diarylamino group, and n represents an integer of 1 to 4. When n is 2 or more, R2 may be the same or different. R3 represents hydrogen or a methoxy group. ] (4) Mr. 1 [In the formula, R represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group, or a heterocyclic group, R2,
R3 may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloralkyl group, a substituted or unsubstituted ara-24-alkyl group, and R2 and R3 are bonded to each other. and may form a nitrogen-containing heterocycle. R4 may be the same or different, hydrogen, an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxy group or halogen. [In the formula, R represents hydrogen or a halogen atom, and Ar represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, or carbazolyl group. ] [In the formula, R4 represents hydrogen, halogen, a cyano group, an alkoxy group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms, R2 represents an alkyl group having 1 to 4 carbon atoms, and R3 is hydrogen, halogen, alkyl group having 1 to 4 carbon atoms, and 1 to 4 carbon atoms
represents an alkoxy group or dialkylamino group, n
is 1 or 2, and when n is 2, R3 may be the same or different, and R4 and R,, are hydrogen and have 1 to 1 carbon atoms.
4 represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted benzyl group. (7) [wherein R is a carbazolyl group, pyridine group, thienyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents dialkylamino group, alkyl group, alkoxy group, carboxy group or ester thereof, halogen atom, cyano group, aralkylamino group, N
-Alkyl-N represents a group selected from the group consisting of an aralkylamino group, an amino group, a nitro group and an acetylamino group. [In the formula, R1 represents a lower alkyl group or a benzyl group, and R2 is substituted with a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, a lower alkyl group, or a benzyl group] It represents an amino group, and n represents an integer of 1 or 2. [In the formula, R1 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, R2 and R3 represent an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, and R4 represents a hydrogen atom or It represents a substituted or unsubstituted phenyl group, and Ar represents a substituted or unsubstituted phenyl group or naphthyl group.

[In the formula, n is an integer of O or l, R□ represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted phenyl group,
R2 and R3 represent hydrogen, a halogen atom, a substituted or unsubstituted alkyl group or an alkoxy group, A represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, and R4 is a hydrogen atom. ,
Alkyl group, alkoxy group, halogen atom alkyl group,
represents a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, R5 and 27-R6 may form a ring), and m is 0, 1.2
or an integer of 3, and when m is 2 or more, R2 may be the same or different. ] 3 [In the formula, R1, R2 and R3 represent hydrogen, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or l. ] In formula C,
R1 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R2' and R3 may be the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom. ] Examples of the compound represented by the general formula (1) include 9-ethylcarbazole-3-aldehyde, 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, and 9-ethylcarbazole-3-aldehyde. and carbazole-3-aldehyde 1,1-diphenylhydrazone.

Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde l-methyl-1
-Phenylhydrazone, 4-methoxynaphthalene-1-
Examples include aldehyde 1-benzyl-1-phenylhydrazone.

Examples of the compound represented by formula (3) include 4-medoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1, 1-diphenylhydrazone, 4-methoxybenzaldehyde 1-benzyl-1-(4-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde 1-benzyl-1-phenylhydrazone,
Examples include 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone.

The compound represented by general formula (4) includes, for example, 1.1
-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 1,1-
Bis(4-dibenzylaminophenyl)propane, 2.
Examples include 2'dimethyl-4,4'-bis(diethylamino)-triphenylmethane.

The compound represented by general formula (5) includes, for example, 9-(
Examples include 4-diethylaminostyryl)anthracene and 9bromo-10-(4-diethylaminostyryl)anthracene.

The compound represented by general formula (6) includes, for example, 9 (4
-dimethylaminobenzylidene)fluorene, 3(9-
Examples include fluorenylidene)-9-ethylcarbazole.

The compound represented by general formula (7) includes, for example, 1, 2
-bis(4-diethylaminostyryl)benzene, 1,
2-bis(2,4-dimethoxystyryl)benzene.

Examples of the compound represented by the general formula (8) include 3t styryl-9-ethylcarbazole and 3-(4-methoxystyryl)-9-ethylcarbazole.

The compound represented by general formula (9) includes, for example, 4-
Diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-
Examples include diphenylaminostyryl)naphthalene and 1-(4-diethylaminostyryl)naphthylene.

The compound represented by the general formula (10) includes, for example, 4'
-diphenylamino-α-phenylstilbene, 4'methylphenylamino-α-phenylstilbene, and the like.

The compound represented by the general formula (11) includes, for example, 1-
Phenyl-3-(4-diethylaminostyryl)-5-
(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-
dimethylaminophenyl) pyrazoline, etc.

The compound represented by general formula (12) includes N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[
1.1'-biphenyl]-4.4'-diamine, N,N
'Diphenyl-N.

7 N'-bis(chlorophenyl)-[], ]1'-biphenyl]-44'-diamine, 3,3'-dimethylbenzidine, etc.

Other hole transport materials include, for example, 2,5 bis(
4-diethylaminophenyl)-1.3.4-oxadiazole, 2,5-bis(4-(4-diethylaminostyryl)phenyl)-1.3.4-oxydiazole,
Oxadiazole compounds such as 2-(9-ethylcarbazolyl-3-)-5-(4-diethylaminophenyl)-1.3.4-oxadiazole, 2-vinyl-4-(
2-chlorophenyl)5-(4-diethylaminophenyl)oxazole, 2(4-diethylaminophenyl)
There are low molecular weight compounds such as oxazole compounds such as -4-phenyloxazole. Further, polymeric compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin can also be used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-1-linitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4,5.7-Titranitroxanthone, 2,4.

8-trinidrothioxanthone, 2,6.8-h linitro 4H-indeno[1,2-b]thiophene-4-
1,3.7-trinitrodibenzothiophene-5
, 5-dioxide, etc.

The photosensitive layer of the electrophotographic photoreceptor of the present invention can be of a dispersed type or a functionally separated type by combining a charge generating substance and a charge transporting substance.

In the case of a dispersed layer structure, a photosensitive layer in which a charge generating substance and a charge transporting substance are dispersed in a binder is provided on a conductive substrate.

In the case of a functionally separated type, a charge generation layer containing a charge generation substance and a binder is formed on the substrate, and a charge transport layer containing a charge transport substance and a binder is formed on top of the charge generation layer. In this case, the charge generation layer and the charge transport layer may be stacked in reverse order. In the case of a functionally separated type, a charge transport substance may be contained in the charge generation layer. In particular, in the case of a positively charged structure, the sensitivity is improved.

Furthermore, an intermediate layer may be provided between the photosensitive layer and the substrate in order to improve adhesion and charge blocking properties. Furthermore, a protective layer may be provided on the photosensitive layer in order to improve mechanical durability such as abrasion resistance. Binders used in forming the charge generation layer, charge transport layer and dispersed photosensitive layer include polycarbonate 1-(bisphenol A type, bisphenol 2 type), polyester, methacrylic resin, acrylic resin, polyethylene, vinyl chloride, vinyl acetate. , polystyrene, phenol resin, epoxy resin, polyurethane, vinylidene chloride, alkyd resin, silicone resin, polyvinyl carbazole, polyvinyl butyral, polyvinyl formal, polyarylate, polyacrylamide, polyamide, phenoxy resin, etc. are used. These binders can be used alone or as a mixture of two or more.

When producing a photoreceptor using the above-mentioned layer structure and materials, there is a preferable range of film thickness and material ratio.

In the case of (product N of substrate/charge generation M/charge transport layer), in the charge generation layer, the ratio of the charge generation substance represented by the general formula (1) to the binder is 20 to 500% by weight, and the film thickness is 0.1-5 μm is preferable. In the charge transport layer, the ratio of the charge transport substance to the binder is preferably 20 to 200% by weight, and the film thickness is preferably 5 to 50 μm).

(Lamination of substrate/charge transport layer/charge generation layer) In the charge transport layer, the ratio of the charge transport material to the binder is preferably 20 to 200% by weight, and the film thickness is preferably 5 to 50 μm. . In the charge generation layer, the charge generation substance represented by the general formula (T) is added in an amount of 10 to 100 times the binder.
It is preferable to contain t%. Furthermore, it is preferable to include a charge transporting substance in the charge generation layer, which has the effect of suppressing residual potential and improving sensitivity. In this case, the charge transport material is 20 to 20% of the binder.
It is preferable to contain 0 parts by weight.

In addition, the amount of compound 6 represented by the general formula (n) of the present invention to be added to the photosensitive layer is 0,000 to the charge transport material when added to the charge transport layer in the case of a functionally separated type.
It is preferable that it is 1 to 50.0 weight 2. When added to the charge generation layer, the amount is 0.01 to 10% relative to the charge generation substance.
Preferably, it is 0.0 weight 2. In the case of decentralized
It is preferable to add 0,001 to 50.0% by weight of the charge transport material.

Generally, the intermediate layer provided as necessary is mainly composed of resin, but considering that the photosensitive layer is coated on top of it with a solvent, these resins are solvent resistant to common organic solvents. It is desirable that the resin has high properties. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate; alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon; and three-dimensional resins such as polyurethane, melamine resin, phenolic resin, and epoxy resin. Examples include curable resins that form a network structure.

Further, fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the intermediate layer to prevent moire and reduce residual potential.

Examples of solvents or dispersion media used in forming the charge generation layer and the charge transport layer include N,N' dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, and dichloromethane. , monochlorobenzene, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and the like.

The photosensitive layer can be formed by immersing the substrate in a coating solution for the charge generation layer or charge transport layer, or by spraying the coating solution onto the substrate.

Substrates used in the electrophotographic photoreceptor of the present invention include metal drums and sheets made of aluminum, brass, stainless steel, nickel, etc., materials such as polyethylene terephthalate, polypropylene, nylon, paper, etc., on which metals such as aluminum and nickel are vapor-deposited. , or titanium oxide,
Examples include sheet-like or cylindrical substrates made of plastic, paper, etc., which are coated with a conductive substance such as tin oxide or carbon black together with a suitable binder to conductivity treatment.

〔effect〕

Since the electrophotographic photoreceptor of the present invention has the above-mentioned structure, the photoreceptor characteristics such as chargeability do not deteriorate even after repeated use over a long period of time, and therefore its practical value is extremely high.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Alcohol-soluble nylon resin (CM-8000, nylon 6/66/6], 0/12 copolymer, manufactured by Toshi Co., Ltd.) 1 was placed on an aluminum drum with a diameter of 80 mm and a length of 340 mm.
A coating solution for an intermediate layer obtained by dissolving 0 parts by weight of methanol in a mixed solvent consisting of 80 parts by weight of methanol and 50 parts by weight of n-butanol was applied by dip coating, and dried at 120°C for 5 minutes to a thickness of 0.0 parts by weight.
A 3 μm intermediate layer was provided. Next, butyral resin (XYH
L: 35 parts by weight manufactured by Union Carbide was dissolved in 150 parts by weight of cyclohexanone, and exemplified compound Nn (6
Add 10 parts by weight of the disazo pigment from 1) and mix with a ball mill.
After dispersing for 8 hours, 210 parts by weight of cyclohexanone was added, and dispersion was continued for 3 hours. This was taken out into a container and diluted with cyclohexanone while stirring so that the solid content was 1.0% by weight. The charge generation layer coating solution thus obtained was dip coated onto the intermediate layer and dried at 120°C for 5 minutes to provide a charge generation layer with a thickness of 0.2 μm. Next, 8 parts by weight of a charge transport substance having the following structural formula (a), 10 parts by weight of polycarbonate resin (Panlite K), 300; manufactured by Teijin Kaoru Co., Ltd., silicone oil (KF-50, manufactured by Shin-Etsu Chemical Co., Ltd.), 0 parts by weight. 0.002 parts by weight, 0.3 parts by weight of α-tocopherol, and 85 parts by weight of methylene chloride to prepare a coating liquid for a charge transport layer. This was applied to the charge generation layer by dip coating and dried at 120° C. for 15 minutes to form a charge transport layer with a thickness of 20 μm. In this way, the photoreceptor of the present invention was produced.

9 Examples 2 to 4 α, an additive to the charge transport layer used in Example 1
A photoreceptor of the present invention was prepared in the same manner as in Example 1 except that the compounds shown in the table below were used in place of tocopherol.

Example 5.6 The disazo pigment in Example 1 was mixed with the exemplified compound Nα(2
A photoreceptor of the present invention was produced in the same manner as in Example 1 except that Nα (35) and Nα (35) were replaced.

Comparative Examples 1 to 3 Three types of photoreceptors for comparison were prepared in the same manner as in Example 1, except that the additives added to the charge transport layer in Example 1 were replaced with those shown in the table below.

40 Example 7 A photoreceptor was prepared in the same manner as in Example 1, except that α-tocopherol (5% by weight based on the charge-generating material) was added to the charge generation layer of Example 1, and α-tocopherol was removed from the charge transport layer. It was created.

FT-5510 (FT-5510), in which each process was modified so that a negatively charged photoreceptor can be attached to the photoreceptor obtained as described above.
■Evaluation was carried out by attaching it to Ricoh M). In addition, in order to evaluate the potential, the developing device was removed and a surface electrometer was attached thereto. Using the above FT-5510, the surface potential was measured at the initial stage and after copying 20,000 sheets. The results are shown in Table 1.

Table] Example 8 8 parts by weight of the charge transport substance used in Example 1, polycarbonate resin (-1,300 for Panlite; manufactured by Yojin Kasei Co., Ltd.)
10 parts by weight, silicone oil (KF-50; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.002 parts by weight, and α-1-copherol 1
Parts by weight were dissolved in 85 parts by weight of methylene chloride to prepare a coating liquid for a charge transport layer. This is φ80nwr, length 340
Dip coating was carried out on a 120 mm aluminum drum.
'C1 was dried for 15 minutes to form a charge transport layer with a thickness of 20 μm.

Next, 10 parts by weight of butyral resin [S-LEC BL-5 (manufactured by Tanezu Chemical Industry Co., Ltd.) was dissolved in 150 parts by weight of cyclohexanone, 1.2 parts by weight of the disazo pigment of exemplified compound Nα (13) was added thereto, and ball milled. 210 parts by weight of cyclohexanone and the structural formula (a
) and 1 part by weight of β-tocopherol were added, followed by dispersion for 3 hours.

This was taken out into a container and diluted with cyclohexanone while stirring so that the solid content became 1.0 weight Z. The charge generation layer coating solution thus obtained was spray coated onto the charge transport layer and dried at 120°C for 10 minutes to a thickness of 4 μm.
A charge generation layer was provided to prepare an electrophotographic photoreceptor of the present invention.

Comparative Example 4 Example 8 except that α-tocopherol was removed from the charge transport layer and β-tocopherol was removed from the charge generation layer.
A photoreceptor was prepared in the same manner as described above.

FT-55, which is a modified photoreceptor obtained as described above.
1,0 (manufactured by Ricoh) and evaluated. The modifications included making it possible to evaluate each process using a positively charged photoconductor, and also making the charger, quenching lamp, and laser writing optical system work even without paper passing. It is something. Furthermore, remove the developing device,
A surface electrometer was attached to it.

Using the above modified copying machine, the surface potential of the photoreceptor was measured at the initial stage and after 20,000 copies were made. The results are shown in Table-2.

Table-2

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which a photosensitive layer containing a charge-generating substance and a charge-transporting substance is provided on a conductive support, a compound represented by the following general formula (I) is used as the charge-generating substance, and An electrophotographic photoreceptor characterized in that the photosensitive layer contains a compound represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, A indicates a coupler residue having a phenolic OH group.) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_1 , R_2, R_3 and R_4 represent a hydrogen atom, a hydroxyl group, an alkoxy group, or an alkyl group (however, at least one of R_1, R_2, R_3 and R_4 is a hydroxyl group), R_5 and R_
6 represents a hydrogen atom, an alkenyl group or an alkyl group. )