JPS63174049A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To stabilize the electrification of the titled body, even after repeating use by using a specific trisazopigment to the titled body as a photoconductive body. CONSTITUTION:The titled body contains one or more kinds of the trisazopigment shown by formula I in the photosensitive layer as the photoconductive body of the titled body. In the formula, A is a coupler residual group having a phenolic hydroxyl group or a coupler residual group of 2-methyl indolenine derivative, A is preferably a residual group shown by formulas II-IV where R1 and R2 are each H atom, or aralkyl group, etc., X is a residual group capable of forming a heterocyclic ring by condensating with a benzene ring, R4 is aralkyl or aryl group, etc., R6 is hydrogen or halogen atom, etc. And, the pigment shown by formula I is incorporated preferably to an electric charge generating layer of the laminated type photosensitive layer. Said layer is produced by applying a dispersion dispersed the pigment shown by the formula I in a binder on a substrate, or by forming a coated film of said pigment on the substrate by a vacuum depositing method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance consisting of a trisazo pigment having a specific structure.

[Prior Art] Electrophotographic photoreceptors containing inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide in the photosensitive layer are well known. On the other hand, organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene, low-molecular organic photoconductors such as carbazole, anthracene, pyrazolines, oxadiazoles, and hydrazones, phthalocyanine pigments, azo pigments, indigo dye,
Organic photoconductors such as thioindigo dyes and methine squaric acid dyes have been developed. Furthermore, as disclosed in, for example, U.S. Pat. No. 4,123,270, U.S. Pat. No. 4,247,614, U.S. Pat. Electrophotographic photoreceptors using photoconductive disazo pigments as charge-generating substances are known.

An electrophotographic photoreceptor using such an organic photoconductor can be produced using a coating method by dip coating by appropriately selecting a binder, so that a photoreceptor with extremely high productivity and low cost can be provided.

Moreover, although it has the advantage of being able to select an organic pigment that exhibits photoconductivity in an appropriate wavelength range, it has drawbacks in sensitivity and durability against repeated use, and so far only a few have been put into practical use.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor containing a novel organic photoconductor in its photosensitive layer.

Still another object is to provide an electrophotographic photoreceptor that has high sensitivity for practical use and exhibits stable charging characteristics even after repeated use.

[Means and effects for solving the problems] The present invention is characterized in that a photosensitive layer provided on a conductive substrate contains at least one trisazo pigment represented by the following general formula (1) as a photoconductor. It consists of an electrophotographic photoreceptor.

In the general formula, A represents a coupler residue having a phenolic OH group or a coupler residue of a 2-methylindolenine derivative.

More specifically, the coupler residue A in the above general formula (1) is, for example, a group represented by any of the following general formulas (2) to (8).

General formula % formula % NO In the formula, R1 and R2 are a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group, an aryl group, a heterocyclic group, an imino group, or a nitrogen atom to which R,, R2 is bonded. Together, they represent a cyclic amino group, X represents a residue condensed with a benzene ring to form a polycyclic aromatic ring or a heterocycle, and R3
and R4 represents an alkyl group, aralkyl group, or aryl group which may have a substituent, Y represents a divalent group of aromatic hydrocarbon or a divalent group forming a heterocycle with a nitrogen atom, and R5 and R6 is a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.

Indicates a cyano group or a nitro group.

In the above definitions, examples of alkyl groups, aralkyl groups, aryl groups, alkoxy groups and heterocyclic groups include alkyl groups such as methyl, ethyl and propyl; aralkyl groups such as benzyl and naphthylmethyl; and aryl groups such as phenyl. , diphenyl, naphthyl, anthryl, etc.; examples of alkoxy groups include methoxy, ethoxy, propoxy, etc.; examples of heterocyclic groups include dibenzofuran, benzimidacylon, benzthiazole, thiazole, pyridine, etc.

Substituents for the above alkyl groups, aralkyl groups, aryl groups, alkoxy groups, heterocyclic groups and imino groups include, for example, halogen atoms, nitro groups, cyano groups, substituted amino groups (e.g. dimethylamino, diphenylamino, dibenzylamino, etc.). ), an alkyl group, an alkoxy group, etc.

Examples of residues that form a polycyclic aromatic ring or heterocycle with the benzene ring of Can be mentioned.

Further, examples of the divalent group of Y include a phenylene group and a naphthylene group.

Representative examples of the trisazo pigment represented by the general formula (1) are listed below.

Note that in the following basic types, only A is different, so only A is shown as an example.

These trisazo pigments can be used alone or in combination of two or more.

These trisazo pigments can be obtained by, for example, tetrazoting a triamine represented by the above in a conventional manner, and coupling thereto a coupler having a group represented by the corresponding general formulas (2) to (8) above in the presence of an alkali. Alternatively, the above-mentioned tetrazonium salts of triamines are isolated in the form of fluoride salts or zinc chloride double salts, and then treated with an alkali in a suitable solvent such as N,N-dimethylformamide or dimethyl sulfoxide. It can be easily produced by the corresponding general formulas (2) to (8).

Synthesis Example of Illustrative Pigment (1) Add 80 ffl of water to a 500 m beaker, add 16 ml of concentrated hydrochloric acid.
6 m (0,19 mol) and the triamine 6.
0 g (0,019 mol) was added thereto and stirred while cooling in an ice water bath to bring the liquid temperature to 3°C.

Next, add 4.2 g (0,061 mol) of sodium nitrite to 7 ml of water.
While controlling the temperature of the solution in the range of 3 to 10°C, the solution was added over 10 minutes. After one drop was added, the solution was stirred at the same temperature for another 30 minutes. Carbon was added to the reaction solution, filtered, and the tetrazotide was added. A liquid solution was obtained.

Next, put 700 rrr of water into a 2-ml beaker and dissolve 21 g of caustic soda (CO0.53 mol), then add 1 ml of naphthol As (3-hydroxy-2-naphthoic acid anilide).
6.2 g (0,061 mol) was added and dissolved. Cool this coupler solution to 6°C, and adjust the liquid temperature to 6-10'C.
The above tetrazotized solution was added dropwise while stirring over a period of 30 minutes, and the mixture was stirred at room temperature for 2 hours, and then left overnight.

The reaction solution was filtered and washed with water to obtain 19.8 g of a crude pigment.

Next, heat oxidation was repeated five times with 400 mfL of N,N-dimethylformamide. Thereafter, 1 g of purified pigment was dried under pressure to obtain 18.1 g of purified pigment.

The yield was 83.6%.

Elemental analysis: Calculated value (%) Experimental value (%) C73,8073,78 H4,074,05 N! 2.30 12.22 The coating containing the trisazo pigment represented by the general formula (1) exhibits photoconductivity, and therefore can be used in the photosensitive layer of an electrophotographic photoreceptor.

The electrophotographic photoreceptor is prepared by forming a film of the trisazo pigment on a conductive substrate by vacuum evaporation, or by dispersing it in a suitable binder to form a film.

In a preferred embodiment of the present invention, the photoconductive coating described above can be used as a charge generation layer in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge generation layer contains as much photoconductive material as possible in order to obtain sufficient light absorption, and in order to shorten the range of the generated charge carriers, the coating 1 should be, for example, 5 μLm or less, preferably 0°01 to 1 μLm. It is desirable to form a thin film with a thickness of m.

This means that most of the incident light is absorbed by the charge generation layer and generates a large number of charge carriers, and that the generated carriers must be injected into the charge transport layer without being deactivated by recombination or trapping. It is caused by something.

The charge generation layer can be formed, for example, by dispersing the trisazo pigment in a suitable binder and coating it on a substrate, or by forming a vapor deposited film using a vacuum vapor deposition apparatus. The charge generation layer can also be used by laminating two or more types of charge generation layers.

The binder that can be used in forming the charge generating layer by coating can be selected from a wide variety of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. Preferably polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.)
, polycarbonate, polyester, phenoxy resin,
polyvinyl acetate, acrylic resin, polyacrylamide,
polyamide, polyvinylpyridine, cellulose resin,
Examples include insulating resins such as polyurethane, epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is 8
A suitable content is 0 double bases % or less, preferably 40i amount % or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the charge transport layer and undercoat layer described below.

Specific organic solvents include methanol, ethanol,
Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, N
, 7amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether,
Esters such as methyl acetate and ethyl acetate, aliphatic I\logenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, or benzene, toluene, silane, ligroin,
Aromatic hydrocarbons such as monochlorobenzene and dichlorobenzene can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, or a spinner coating method.

Drying is preferably carried out by drying to the touch at room temperature and then heating. Drying by heating is performed at a temperature of 30 to 200°C for 5 minutes to
It can be carried out stationary or under blown air for a time in the range of 2 hours.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field, and transporting these charge carriers to the surface. have. At this time, this charge transport layer may be laminated on or under the charge generation layer.

Charge-transporting substances include electron-transporting substances and hole-transporting substances, and electron-transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-IJnitro-9- Fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-dolinitro-9-dicyanomethylenefluorenone, 2,4,5,7-titranitroxanthone,
Examples include electron-withdrawing substances such as 2,4,8-trinidrothioxanthone, and polymerized versions of these electron-withdrawing substances.

Pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N-
Phenylhydrazino-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, l,3,3-trimethylindolenine-ω-aldehyde-N.

Hydrazones such as N-diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadiazole, 1- Phenyl-3-(p-diethylaminostyryl)-5-<
P-diethylaminophenyl)pyrazoline, l-[6-
Medoxypyridyl(2)]-3-(p-diethyl7minostyryl)-'5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(3)]-3-(p
-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3
-(p-diethylaminostyryl)-4-methyl-5-
(p-diethylaminophenyl) hilazoline, l-2-phenyl-3-(α-benzyl-P-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(p-diethylaminostyryl) -6-dinithylaminobenzoxazole, 2-(p-diethylaminophenyl)-4
-(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole and other oxazole compounds,
Thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, l.

1-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1,2.2-tetrakis(4-
Polyarylalkanes such as N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine,
Poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinyl acridine, poly-
Examples include 9-vinylphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as binders include acrylic resin,
polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or organic photoconductive polystyrene such as poly-N-vinylcarbazole polyvinylanthracene and polyvinylpyrene. It will be done.

The charge transport layer has a limit in its ability to transport charge carriers, so it cannot be made thicker than necessary. Generally, the thickness is 5 to 30 pm, but the preferred range is 8 to 20 pm.
It is m. When forming a charge transport layer by coating,
Any suitable coating method, such as those described above, can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. Examples of the substrate having a conductive layer include those whose substrate itself is conductive, such as aluminum, aluminum alloy, copper, zinc,
Stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, and platinum are used.

In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoride, ethylene chloride, etc.), conductive particles (e.g. carbon black, silver particles, etc.) coated on plastic with a suitable binder, substrates in which plastic or paper is impregnated with conductive particles, plastics containing conductive polymers, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer can be formed from casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. . The appropriate thickness of the undercoat layer is 0.1 to 5 m, preferably 0.5 to 3 m.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, the surface of the charge transport layer must be positively charged, and exposure after charging is required. Then, in the light band area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the positive charge, resulting in a decrease in surface potential and an electrostatic charge transport layer between it and the unexposed area. occurs. A visible image is obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper or plastic film and then developed and fixed. Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or methods, and are not limited to specific ones.

On the other hand, when the charge transport material is made of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. , which then reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between the surface potential and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to when an electron transporting substance is used.

Furthermore, as another specific example of the present invention, the above general formula (1)
Examples include an electrophotographic photoreceptor in which an organic photoconductor which is a trisazo pigment represented by the above formula is contained in the same layer together with the charge transporting substance described above.

At this time, the charge diameter is made of polyvinylcarbazole and trinitrofluorenone as charge transport materials.

Imperial compounds can be used.

The electrophotographic photoreceptor of this example can be prepared by dispersing the above-described organic photoconductor and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a film thereon.

In any of the electrophotographic photoreceptors, the pigment used contains at least one type of pigment selected from trisazo pigments represented by the general formula (1), and if necessary, pigments with different light absorptions are used in combination. For the purpose of increasing the sensitivity of the body or obtaining a panchromatic photoreceptor, the general formula (1
) A combination of two or more types of trisazo pigments,
Alternatively, it can also be used in combination with a charge generating substance selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers and CRT printers.

[Example] Example 1 Ammonia aqueous solution of casein (casein 1
1.2g, 28% ammonia water 1g, water 222mfL)
Meyer bar! The coating was applied so that the film thickness after drying was 1.0 JLm, and then dried.

Next, 5 g of the organic photoconductor of the exemplary pigment (7) was added to 95 mJl of ethanol with butyral resin (butyralization degree 6).
Add 2 g of 3 mol%) to the solution and add 2 g with an attritor
Spread out time. This dispersion was applied onto the previously formed casein layer using a Mayer bar so that the film thickness after drying was 0.5 gm.

5g of hydrazone compound and polymethyl methacrylate (
A charge transport layer was formed by dissolving 5 g of the number average molecular weight v0,000 in 70 ml of benzene, and applying the solution onto the charge generation layer using a Mayer bar so that the thickness after drying would be 12 pm, and drying to form a charge transport layer.

The electrophotographic photoreceptor thus prepared was placed in an electrostatic copying paper test bag
i [5P-428 (turntable)] was statically charged with corona at 15 KV, held in a dark place for 1 second, and then exposed to light at an illuminance of 2 UX to examine charging characteristics.

The charging characteristics include the surface potential (vO) and the required exposure amount (El
/2) was measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when used for green reversal, the electrophotographic photoreceptor prepared above was used.
It was attached to the cylinder of an electrophotographic copying machine equipped with a 5.6 KV corona charger, an exposure optical system with an exposure amount of 5 mux, sec, a developing device, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as a cylinder is driven.

Using this copying machine, the initial bright area potential (VL) and dark area potential (VD) and the bright area potential (VL) and dark area potential (VD) after 5,000 uses were measured. The results are shown below.

Vony 610V, El/2: 2.8mm ux, sec Initial After durability of 5,000 sheets Examples 2 to 15 Except for using the following illustrative pigments instead of the illustrative pigments used in Example 1. <An electrophotographic photoreceptor was produced in the same manner as in Example 1.

The charging characteristics and durability characteristics of each photoreceptor were measured in the same manner as in Example 1.

Show the results.

; 8.6-12
(18) +3 (21)2
605 2.63
610 2.94
B10 3.25 600
2.86 620
3, 17 605
2, 98 610 3
．． 29 625 3.41
0 600 2, 811
610 3.012
615 3.313
620 3.414 620
3.015 625
3.214 B25 45
665 8015 630 40
670 85° Example 16 On the charge generation layer prepared in Example 1, 5 g of 2.4.7-dolinitro-9-fluorenone and poly-4,4-dioxydiphenyl-2,2-propane carbonate (molecular weight 30 A coating solution prepared by dissolving 5 g of 1,000 g/m2 in 70 m of tetrahydrofuran was applied so that the coating amount after drying was 10 g/m2, and then dried.

The charging characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. At this time, the charge was set to 10. Show the results.

VO: +600V, E 1/2: 6, 2x ux, sec.

Initial Vo: +610V, VL: +40V VD after 5,000-sheet durability: +635V, vL: +85V Example 1
7 A film thickness of 1.5 mm was applied to the aluminum surface of the aluminum vapor-deposited polyethylene terephthalate film. A coating of Ogm polyvinyl alcohol was formed.

Next, the dispersion of the exemplary pigment (7) used in Example 1 was applied onto the polyvinyl alcohol layer formed earlier using a Meyer bar so that the film thickness after drying would be 0.54 m, and dried. A charge generation layer was formed.

Then 1-[pyridyl(2)-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)
A solution prepared by dissolving 5 g of pyrazoline and 5 g of polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid) in tetrahydrofuran 7001 was applied onto the charge generation layer so that the film thickness after drying was 1103 hours. , and dried to form a charge transport layer.

The charging characteristics and durability characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

Vo knee 620V, El/2: 3.3 Mux, sec.

Initial Vn knee 625V, VL knee 40V Vo after 5,000 sheets durability: -670V, VL: -85V Example 1
8. Apply casein ammonia aqueous solution on an aluminum plate with a thickness of 100 #Lm and dry to a film thickness of 1.0. A wm subbing layer was formed.

Next, 5 g of 2,4.7-)linitro-9-fluorenone
A charge transfer complex compound was prepared by dissolving 5 g of poly-N-vinylcarbazole (number average molecular weight: 300,000) in 70ml of tetrahydrofuran.

Photoconductor 1 of this charge transfer complex compound and exemplary pigment (19)
g, 5 g of polyester resin and 70 g of tetrahydrofuran.
It was added to the solution dissolved in mJl and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 12 μm, and dried.

Example 1 Charging characteristics of the electrophotographic photoreceptor thus prepared
It was measured in the same manner as.

However, the charging polarity was set to 10. Show the results.

vo: +595V, El/2: 6.8J! ux, se'c, [Effects of the Invention] By using a trisazo pigment with a specific structure in the photosensitive layer, the electrophotographic photoreceptor of the present invention improves either carrier generation efficiency or carrier transport efficiency within the photosensitive layer containing the trisazo pigment. It is estimated that one or both of them will be improved, resulting in remarkable effects such as high sensitivity and excellent potential stability during long-term use.

Claims (3)

[Claims] (1) The following general formula (
An electrophotographic photoreceptor comprising at least one of the trisazo pigments shown in 1) as a photoconductor. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) In the formula, A represents a coupler residue having a phenolic OH group or a coupler residue of a 2-methylindolenine derivative. (2) The electrophotographic photoreceptor according to claim 1, wherein the coupler residue A in the general formula (1) is a coupler residue selected from the groups represented by the following general formulas (2) to (8). General formulas ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (3) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼(5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (6) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (7) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (8) In the formula, R_1 and R_2 are A hydrogen atom, an alkyl group that may have a substituent, an aralkyl group, an aryl group, a heterocyclic group, an imino group, or a cyclic amino group together with the nitrogen atom to which R_1 and R_2 are bonded, and X is fused with a benzene ring. represents a residue forming a polycyclic aromatic ring or a heterocycle, R_3 and R_4 represent an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and Y represents a divalent aromatic hydrocarbon. It represents a divalent group that forms a heterocycle with a group or a nitrogen atom, and R_5 and R_6 represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a cyano group, or a nitro group. (3) The photosensitive layer is a laminated photosensitive layer consisting of a charge generation layer and a charge transport layer, and the charge generation layer has the general formula (1).
The electrophotographic photoreceptor according to claim 1, which contains a trisazo pigment represented by: