JPS63218960A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity, durability and above all, the potential stability at the time of durable use by using a specific trisazo pigment for a photosensitive layer. CONSTITUTION:This photosensitive body has the photosensitive layer contg. the trisazo pigment expressed by the formula I on a conductive substrate. In the formula I, R1, R2 respectively denote a hydrogen atom, halogen atom, cyano group, alkyl group which may have a substituent, aryl group, aralkyl group or alkoxy group; A denotes a residual coupler group having a phenolic hydroxyl group; Ar denotes a carbon cyclic arom. group or heterocyclic arom. group which may have a substituent; Z denotes a methylene group which is of a single bond or may have a substituent, ethylene group, oxygen, sulfur or substd. amino group. The photosensitive body having the high sensitivity and excellent durability is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an electrophotographic photoreceptor using a novel photoconductive material.

[Conventional technology]

Conventionally, pigments and dyes exhibiting photoconductivity have been published in numerous publications. For example, RCA Rev
iew” Vol, 23, P, 413~P,
419 (1962, 9), the photoconductivity of 7-thalocyanine pigment was published, and an electrophotographic photoreceptor using this 7-thalocyanine pigment was disclosed in U.S. Patent No. 339.
This method is disclosed in Japanese Patent No. 7086, US Pat. No. 3,816,118, and the like. In addition, examples of organic semiconductors used in electrophotographic photoreceptors include U.S. Pat. No. 4,315,983, U.S. Pat. No. 4,327,169, and "Ra5ea".
ah Disclosure”20517 (1981
, 5), the pyrylium dye shown in U.S. Patent No. 3
Examples include the square phosphoric acid methine dye shown in Japanese Patent No. 824099, and the disazo pigment shown in US Pat. No. 3,898,084, US Pat. No. 4,251,613, and the like.

Such organic semiconductors are easier to synthesize than inorganic semiconductors, and can be synthesized as compounds that have photoconductivity for light in the required wavelength range. An electrophotographic photoreceptor formed on a conductive support has the advantage of improved color sensitivity, but only a few of them are practical in terms of sensitivity and durability.

[Problems to be solved by the invention]

The present invention has been made in order to solve the conventional problems and provide an electrophotographic photoreceptor that is highly sensitive and has excellent durability.

[Means to solve the problem]

The electrophotographic photoreceptor of the present invention is characterized by having a photosensitive layer containing a disazo pigment represented by the following general formula CI) on a conductive substrate.

〔Record〕

General formula CI) R1 and R2 in general formula CI) each represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group which may have a substituent, an aryl group, an aralkyl group, or an alkoxy group. Examples of the halodane atom include fluorine, chlorine, iodine, and bromine atoms.

The alkyl group is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group,
Examples include n-propyl group, 1so-propyl group, n-butyl group, 5ea-'butyl group, tart-butyl group, and the like. Examples of the aryl group include phenyl group. Examples of the aralkyl group include N, tb-)silyl group, benzyl group, phenethyl group, naphthylmethyl group, and the like. Examples of the alkoxy group include methoxy group, ethoxy group, and zoloboxy group.

When R1 is an alkyl group, an aralkyl group, an alkoxy group, or an aryloxy group, examples of substituents include fluorine, chlorine, iodine,
Halogen atoms such as bromine, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl (except when R4 is an alkyl group), alkoxy groups such as methoxy, ethoxy, glopoxy, phenoxy (where R1 is an alkoxy group) ), nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, pyrrolidino, and other amine groups that may have substituents.

A and A' in general formula (1) each represent a coupler residue having a phenolic OH group, and A and A' may be the same or different. Preferred specific examples of the coupler residues represented by A and A' are represented by the following general formulas (II) to (II).

General formula (ff) In the general formula (II), X is a polycyclic aromatic ring such as a 7talene ring or an anthracene ring, or a carbazole ring, a benzcarbazole ring, or a dibenzofuran ring, which is fused with a be/zene ring in the formula. Indicates the atomic group necessary to form a heterocycle such as a ring, a dipenzonaphthofuran ring, and a diphenylene sulfide ring.

The ring formed by X when condensed with a benzene ring is more preferably a naphthalene ring, anthracene ring, carbazole ring or benzcarbazole ring.

R2 and R3 each represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, or form a cyclic amino group together with the nitrogen atom bonded to R2 and R3. Represents the required atomic group.

Specific examples of alkyl groups include methyl group, ethyl group, globyl group, butyl group, etc. Specific examples of aralkyl groups include benzyl group, phenethyl group, naphthylmethyl group, etc. Specific examples of aryl groups include, for example. Examples of heterocyclic groups include phenyl group, diphenyl group, naphthyl group, anthryl group, etc., and examples of heterocyclic groups include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine, in which one hydrogen atom is removed from the heterocycle. General formula [■] H General formula CM') General formula (III), R4 and R5 in (It/) are each a hydrogen atom, an alkyl group that may have a substituent, or an aryl group. , represents an aralkyl group. Specific examples of alkyl groups, aryl groups, aralkyl groups, and substituents therefor include the same examples as for R2 and R3 above.

Substituents R2, R5, R4, R5 in formula (II) to [■]
The alkyl group, aryl group, aralkyl group, alkoxy group or heterocyclic group represented by may further include other substituents, such as halodane atoms such as fluorine, chlorine, iodine and bromine, methyl group, ethyl group, glovyl group, inglovir group, butyl Alkyl groups such as groups (excluding cases where R2, etc. is an alkyl group), alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy groups (excluding cases where R2, etc. is an alkoxy group)
, a nitro group, a cyano group, a trimethylamino group, a zope/nolamino group, a diphenylamino group, a morpholino group, a piperidino group, a pyrrolidino group, and the like. .

General formula (V) H General formula (■) 5Y2, Yl and Y2 each contain a divalent group of aromatic hydrocarbon or a nitrogen atom (two nitrogen atoms in the formula) in the ring c! Indicates a divalent ring group.

Examples of divalent groups of aromatic hydrocarbons include divalent groups of monocyclic aromatic hydrocarbons such as 0-7 enylene, o-naphthylene, yrinaphthylene, 1,2-antrylene, and 9. Examples include divalent groups of condensed polycyclic aromatic hydrocarbons such as lo-7 enanthriley. Also, 2 of the Peter term containing a nitrogen atom in the ring
As the valent group, 3,4-pyrazolediyl group, 2,3
-pyridinediyl group, 4,5-pyrimidinediyl group, 6
, 7-indazolediyl group, and 6,7-chiralindiyl group.

General formula [■] R6 represents an aryl group or a heterocyclic group which may have a substituent, specifically an aryl group such as a phenyl group or a naphthyl group, an anthryl group, a pyrenyl group, a pyridyl group, or a chenyl group. , a heterocyclic group such as a furyl group or a carbazolyl group.

When the aryl group or heterocyclic group represented by R6 has a substituent, examples of the substituent include halodane atoms such as fluorine, chlorine, iodine, and bromine, and alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, and butyl group. , an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a phenoxy group, a nitro group, a cyano group, a dimethylamino group, a dibenzylamino group, a diphenylamino group, a morpholino group, a piperidino group, a pyrrolidino group, etc. Examples include amine groups that may be substituted.

X2 has the same meaning as X2 in general formula (II).

R7 and R8 in the formula X3' represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent. Specifically, alkyl groups such as methyl group, ethyl group, propyl group, butyl group, aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, heptalyl groups such as phenyl group, naphthyl group, anthryl, diphenyl group, A heterocyclic group obtained by removing one hydrogen atom from a heterocyclic ring such as carbazole, dibenzofuran, benzimidacylon, benzthiazole, thiazole, and pyridine.

When the alkyl group, aryl group, aralkyl group, or heterocyclic group represented by R, R8 in formula [■] has a substituent, the substituent includes a halogen atom such as fluorine, chlorine, iodine, or bromine, a methyl group, Alkyl groups such as ethyl group, propyl group, isopropyl group, butyl group (excluding cases where R, etc. is an alkyl group), alkoxy groups such as methoxy group, ethoxy group, propoxy group, nitro group, 77 group, dimethyl group Examples include amine groups that may have substituents such as an amino group, a dibenzylamino group, a diphenylamino group, a morpholino group, a piperidino group, and a pyrrolidino group.

Ar in the general formula CI) represents a carbocyclic aromatic ring group or a heterocyclic aromatic ring group which may have a substituent, specifically a carbocyclic group such as benzene, naphthalene, anthra7ane, etc. A group obtained by removing two hydrogen atoms from an aromatic ring or furan,
Represents a group obtained by removing two hydrogen atoms from a heterocyclic aromatic ring such as pyrrolecargenic acid, thiophene, pyridine, pyrazine, etc., and represents a carbocyclic aromatic ring group or a heterocyclic aromatic ring group represented by Ar1 + Ar2. When has a substituent, the substituent includes a halogen atom such as fluorine, chlorine, iodine, and bromine, an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a methoxy group, an ethoxy group,
Alkoxy groups such as propoxy groups, nitro groups, cyano groups,
Examples include amino groups that may have substituents such as dimethylamino group, dibenzylamino group, diphenylamino group, morpholino group, piperidino group, and pyrrolidino group.

2 in general formula (1) represents a methylene group, ethylene group, oxygen, a sulfur atom, or a substituted amino group which may have a single bond or a substituent, and the substituent of the methylene group or ethylene group is fluorine, Examples include halogen groups such as chlorine, iodine, and bromine, alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy, and cyano groups, and as substituents for substituted amine groups. Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and aryl groups such as phenyl and naphthylanthryl.

Next, a general method for producing the trisazo pigment of general formula (1) used in the present invention will be described. The trisazo pigment represented by the general formula CI) is produced by converting the trisamine h2 moiety represented by the general formula (9) into a hexazonium salt using a conventional method such as sodium nitrite or nitrosyl sulfate, and performing aqueous coupling with A, which is a coupler component. The obtained tetrazonium salt was taken out as a stable salt such as borofluoride salt, and then added to DMF.
It can be obtained by carrying out a coupling reaction in an organic solvent such as '.

Next, specific examples of the trisazo pigment of general formula (1) used in the present invention are listed below. However, the trisazo pigment shown in the following specific examples does not limit the present invention.

-@mon g
A coating containing the trisazo pigment of general formula (1) shown above exhibits photoconductivity, and therefore can be used in the photosensitive layer of the electrophotographic photoreceptor described below.

That is, in a specific example of the present invention, the trisazo pigment of general formula (1) is formed on a conductive substrate by vacuum deposition, or by dispersing it in a suitable binder to form a film! A child photographic photoreceptor can be constructed.

In a preferred embodiment of the present invention, the above-mentioned film exhibiting photoconductivity may be applied 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. can.

The charge generation layer contains as much of the above-mentioned photoconductive compound as possible in order to obtain sufficient absorbance, and is a thin film layer, for example, 5 μm or less, in order to shorten the range of the generated charge carriers. , preferably a thin film layer having a thickness of 0.01 to 1 μm. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers can be recombined or captured (trough f) without being deactivated. This is due to the need to inject into the transport layer.

The charge generation layer can be formed as described above, for example, by dispersing the trisazo pigment of general formula (1) in a suitable binder and coating it on the substrate, or by vapor deposition using a vacuum vapor deposition apparatus. It can be obtained by forming a film. Binders that can be used to form the charge generating layer by coating can be selected from a wide range of P3 green resins, as well as organic photoconductive I-limers such as poly-N-vinylcarbazole, &rivinyanthracene and polyvinylpyrene. You can choose. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.) or carbonate, ? Reester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, ? Liamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, ? Rivinyl alcohol? Examples include insulating resins such as lipinylpyrrolito. The resin contained in the charge generation layer is 80% by weight or less, preferably 40% by weight.
The following are suitable.

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 or undercoat layer described below. Specific organic solvents include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; aliphatic halodanes such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene. Hydrocarbonized water 5Hel penze/, toluene, xylene, ligroin, monochlorobenzene,
Aromatics such as dichlorobenzene can be used.

Coating methods include dip coating method, spray coating method, spinner coating method, peed coating method,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to perform finger drying at room temperature and then heat drying. Heat drying at a temperature of 306C to 200C for 5 minutes.
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. In this case, the charge transport layer may be located on the far side from the charge generation layer when viewed from the conductive substrate, or may be located between the charge generation layer and the charge generation layer.

When the charge transport layer is formed on the side farther from the charge generation layer,
The substance that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport substance) is preferably substantially insensitive to the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. The term "electromagnetic waves" used herein includes a broad definition of "light rays" including r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared rays, and the like. When the photosensitive wavelength range of the charge transport layer coincides with or overlaps that of the charge generation layer, charge carriers generated in both layers capture each other, resulting in a decrease in sensitivity.

Charge transporting substances include electron transporting substances and hole transporting substances, and electron transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, and 2,4.7-)dinitro-9. -fluorenone, 2,4,5.7-tetranitro-9-fluorenone,
2,4.7-) dinitro-9-dicyanomethylenefluorenone, 2,4,5,7-ketone nitroxanthone,
There are electron-withdrawing substances such as 2,4.8-trinidrothioxanthone, and polymerization of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N-ethylcarbasol, N-f-sopropylcar/4-sol, N-methyl-
N-phenylhydrazino-3-methylythene-9-ethylcarbasol, N,N-diphenylhydrazino-3-
Methylidene-9-ethelcarnoguzole, N, N-・
Diphenylhydrazino-3-methylidene-10-ditylphenothiazine, N,N-diphenylhydrazino-3
-Methylidene-10-ethylphenoxazine, p-diethylaminobenzaldehyde-N,N-diphenyl P
h-syn, p-diethylaminobenzaldehyde-N-α
-Naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone,
1.3+3- 1,1 methylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-noethylpenzaldehyde 3-methylbenzthiazolinone-2
- Hydrazo 7 such as hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxazoazole, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline ,
1-('l'/su#(2)) -3-(p-diethylaminosf !J le)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)) -3-
(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[6-medoxypyrisol (2)) -3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)hirazoline, 1-[pyridyl (3)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[lepidyl (2))-3-(p-diethylaminostyryl)-5-(p -diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3-
(p-diethylaminostyryl-4-methyl-5-(p
-diethylaminophenyl) pyrazoline, 1-(piritur (2)) -3-(α-methyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl) -4-Methyl-5-(p-diethylaminophenyl)hilazoline, 1-phenyl-3-(α-benzyl-
p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(p-diethylaminostyryl)-6
-Oxazole compounds such as 2-(p-diethylaminophenyl)-4-(p-tmethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2-(p-diethylaminophenyl)oxazole, Thiazole compounds such as styryl)-6-dinithylaminopenzothiazole, bis(4-noethylamino-2-)f
triarylmethane compounds such as (ruphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamino-2-methylphenyl)heguta/, 1.1,2.2-
Prearyl alkanes such as tetrakis(4-N,N-trimethylamino-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylant Examples include 2-carbon, fillet/-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 substances 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 co-I remer,
Insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. be able to.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30 μm, but the preferred range is 8 to 20 μm.
It is μm. When forming the charge transport layer by coating, an appropriate coating method as 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 conductive substrate having, for example, a conductive layer. As the substrate having the conductive layer, materials that are conductive themselves such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, and platinum can be used. In addition, plastics (e.g., polyethylene, polyzolopyrene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, Polysulfated ethylene, etc.), conductive particles (e.g. carden black, silver particles, etc.) coated on glass with a suitable binder, conductive particles impregnated into plastic or paper, or conductive/rimer. It is possible to use a glass stick having the following properties.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. Subbing layer, casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic M-:! , iF') mer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane,
It can be formed from gelatin, aluminum oxide, etc.

The thickness of the undercoat layer is 0.1 to 5 μm, preferably 6.0 μm. s
~3 μm is appropriate.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are arranged in this order, and the charge transport material is an electron transport material, the surface of the charge transport layer must be positively charged. When exposed to light, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the positive charge, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area. arise. A visible image can be 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, plastic film, etc. 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 known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, it is necessary to charge the surface of the charge transport layer negatively. When exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. After that, it reaches the surface and neutralizes the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area.

During development, it is necessary to use a positively charged toner, contrary to the case where an electron transporting substance is used.

When using a photoreceptor in which a conductive layer, a charge transport layer, and a charge generation layer are arranged in this order, if the charge transport material is an electron transport material, the surface of the charge generation layer must be negatively charged. When exposed to light, electrons generated in the charge generation layer in the exposed portion are injected into the charge transport layer and then reach the conductive substrate.

On the other hand, holes generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a positively charged toner. This can be directly fixed, or the toner image can be transferred to i or a glass 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 generation layer is made of a hole transporting substance, the surface of the charge generation layer must be positively charged, and when exposed to light after charging, the holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. and then reaches the conductive substrate. On the other hand, electrons generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area.

During development, it is necessary to use a negatively charged toner, contrary to the case where an electron transporting substance is used.

Further, in another specific example of the present invention, the above-mentioned hyPrazones,
Organic photoconductive substances such as pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamine, poly+N-vinylcarbazoles, and inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. The photosensitive film may contain the trisazo pigment of general formula CI) as a sensitizer.

This photosensitive coating is formed by coating these photoconductive substances and the trisazo pigment of general formula CI) together with a binder.

Another specific example of the present invention is an electrophotographic photoreceptor in which a trisazo pigment of the general formula CI) is contained in the same layer as a charge transport material. In this case, in addition to the above-mentioned charge transport substance, a charge transfer complex compound consisting of poly+N+vinylcarbazole and trinitrofluorenone can be used.

The electrophotographic photoreceptor of this example can be prepared by dispersing the trisazo pigment of general formula CI) and the charge transfer complex compound in a solution of polyester dissolved in tetrahydrofuran, and then forming a film thereon.

The pigment used in any of the photoreceptors contains at least one type of pigment selected from trisazo pigments represented by the general formula (1), and its crystal form may be amorphous or crystalline. Also, if necessary, pigments with different light absorptions are used in combination to increase the sensitivity of the photoreceptor! For the purpose of obtaining a chromatic photoreceptor, it is also possible to use a combination of two or more types of disazo pigments represented by the general formula CI), or in combination with a charge generating substance selected from known dyes and pigments. be.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers, L
It can also be widely used in electrophotographic applications such as ED printers, liquid crystal printers, and radar plate making.

〔Example〕

The present invention will be explained below with reference to Examples.

Examples 1 to 25 Casein ammonia aqueous solution c casein y1 on an aluminum plate
1.2es, ammonia water 1? , water 222 m/) was applied using Mayer Parr so that the film thickness after drying was 1.0 μm, and then dried.

Next, the above-mentioned trisazo pigment 415iP was added to ethanol 95d with butyral resin (butyralization degree 63 mol%).
It was added to the solution containing 2iP and dispersed for 2 hours using a sand mill. This dispersion was applied onto the previously formed casein layer using a Mayer Par so that the film thickness after drying would be 0.5 μm, and dried to form a charge generation layer. Next, hydrazone compound 5iP having the structural formula and polymethyl methacrylate resin (number average molecular weight 100,000') 5y- were dissolved in benzene 70g, and this was applied onto the charge generation layer using a Mayer par so that the film thickness after drying would be 12 μm. The photoreceptor of Example 1 was prepared by coating and drying to form a charge transport layer. Photoreceptors corresponding to Examples 2 to 25 were prepared in exactly the same manner as in Examples 2 to 25 using other exemplary pigments shown in Tables 8g1 to 3 instead of trisazo pigment S1.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
Using an electrostatic copying paper tester Mode I SP-428, the sample was statically charged with a corona at -5 kV, held in a dark place for 1 second, and then exposed to light at an illuminance of 2 Lux to examine its charging characteristics. The charging characteristics include the surface potential (VO) and the exposure f04 required to strongly attenuate the potential when dark decayed for 1 second.
was measured. The results are shown in Table 1.

Table 1 Examples 26 to 29 The photoreceptors used in Examples 2, 14, 16, and 22 were used to measure changes in bright area potential and dark area potential during repeated use. The method uses a -5.6kV corona charger, an exposure optical system,
This electrophotographic copying machine is equipped with a developing device, a transfer charger, a static elimination exposure optical system, and a cleaner, and a photoreceptor is attached to the cylinder.As the cylinder is driven, an image is formed on the transfer paper. ing. Using this copier, the initial light potential (Vt, ) and dark potential (vn) were set to around -io ov and -600V, respectively, and the light potential (ML) and dark potential ( Vo) was measured. The results are shown in Table 2.

Example 30 On the charge generation layer prepared in Example 2, 2,4.7-dolinitro-9-fluorenone 4M', IelJ-4,
The coating volume after drying of a coating solution prepared by dissolving 4'-dioxydiphenyl-2,2'-gulonocune carbonate (molecular weight 300,000) 5/- in 70% tetrahylofuran was 1077 m2. Apply it as desired and let it dry.

The electrostatic charge of the electrophotographic photoreceptor thus prepared was measured in the same manner as in Example 1. At this time, the charging polarity was set to ten. The results are shown below.

Vo: ■ 600M Luft E%: 3.5 tux-sec Example 31 A polyvinyl alcohol film having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film. Next, the dispersion of the trisazo pigment used in Example 2 was applied onto the previously formed polyvinyl alcohol layer using a Mayer coating so that the film thickness after drying was 0.5μ, and dried to form a charge generation layer. did. Next, a solution obtained by dissolving a pyrazoline compound of the structural formula 5iP and a polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-iso7thalic acid) 5iP in tetrahydro-70rane 70rILl was placed on the charge generation layer so that the film thickness after drying was determined. It was coated to a thickness of 10μ and dried to form a charge transport layer. Thus PJ4
The charging characteristics and durability characteristics of the produced photoreceptor were measured in the same manner as in Example 26. The results are shown in Table 3. Vo: C) 655 zhtEV2: 2.
8 tux, sea Table 3 (Durability characteristics) As shown in Table 3, the sensitivity is good and the potential stability during long-term use is also good.

Example 32 An ammonia aqueous solution of casein was coated on an aluminum plate with a thickness of 100μ and dried to form a subbing layer of 0.5μ.

Next, 2.4.7-) dinitro-9-fluorenone and poly-N-vinylcarbazole (number average molecular weight 300
000 ) sp- was dissolved in tetrahydrofuran 70d to form a charge transfer compound. This charge transfer complex compound and the above-mentioned exemplified trisazo pigment A22.1? was added to a solution prepared by dissolving a polyester resin (Iron: Toyobo Co., Ltd.) in Tetrahydro 7ran 70M1 and dispersed. This dispersion was applied onto the undercoat layer and dried to prepare a 12μ photoreceptor.

The charging characteristics and durability characteristics of the photoreceptor thus prepared were measured in the same manner as in the actual photoreceptor. The results are shown below. However, the charging polarity was set to ■.

Vo: (E) 615 V E%: 3.5 tux, s@c Example 33 The charge transport layer and charge generation layer of Example 2 were placed on the casein layer of the aluminum base coated with the casein layer used in Example 32. A photoreceptor was formed in the same manner as in Example 1 except that the layers were sequentially laminated and the layer structure was different, and the charging characteristics were measured in the same manner as in Example 1. However, the charging polarity was set to ■. The results are shown below.

vo: ■ 605 v ElA: 4. [Effects of the Invention] According to the present invention, by using a specific trisazo pigment in a photosensitive layer, it is possible to improve either carrier generation efficiency or carrier transport efficiency within the photosensitive layer containing the azo pigment. It is surmised that one or both of them will be improved, and as a result, an electrophotographic photoreceptor with high sensitivity, durability, and, in particular, excellent potential stability during long-term use will be constructed.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing a trisazo pigment represented by the following general formula [I] on a conductive substrate. [Note] General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc.
represents an aryl group, an aralkyl group or an alkoxy group, A represents a coupler residue having a phenolic hydroxyl group, Ar represents a carbocyclic aromatic group or a heterocyclic aromatic group which may have a substituent, and Z (2) A_1, A_2, or A_3 of general formula [I]
is the following general formula [II], general formula [III], general formula [IV],
The electrophotographic photoreceptor according to claim 1, which is a coupler residue represented by general formula [V], general formula [VI], general formula [VII], or general formula [VIII]. [Note] General formula [II] ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ In the formula, X_1 represents the atomic group necessary to form a polycyclic aromatic ring or a heterocycle condensed with the benzene ring in the formula. show. R_2 and R_3 each represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, or form a cyclic amino group with the nitrogen atom bonded to R_2 and R_3. represents the atomic group necessary to General formula [III] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, R_4 is an alkyl group that may have a substituent,
Indicates an aryl group or an aralkyl group. General formula [IV] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, R_5 is an alkyl group that may have a substituent,
Indicates an aryl group or an aralkyl group. General formula [V] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, Y_1 is a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring containing two nitrogen atoms in the formula. show. General formula [VI] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ Y_2 in the formula represents a divalent group of aromatic hydrocarbon or a divalent group of heterocycle containing a nitrogen atom in the ring. General formula [VII] ▲There are numerical formulas, chemical formulas, tables, etc.▼ In the formula, R_6 represents an aryl group or a heterocyclic group that may have a substituent, and X_2 has the same meaning as X_2 in general formula [II]. has. General formula [VIII] ▲ Numerical formulas, chemical formulas, tables, etc. are included▼ In the formula, R_7 and R_8 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group that may have a substituent. X_3 represents the same meaning as X_1 in general formula [II].