JPS63172165A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To maintain a practicable sensitivity characteristic and stable potential characteristic in repetitive use by incroporating a specific trisazo pigment into a photoconductive layer. CONSTITUTION:This photosensitive body contains the trisazo pigment expressed by the formula in the photoconductive layer. In the formula, R1 and R2 denote an alkyl group, aryl group, aryl group, aralkyl group or alkoxy group which may have a substituent, or halogen atom or cyano, group, R3 and R4 denote a hydrogen atom or electron withdrawing group, A denotes a residual coupler group having a phenolic hydroxyl group, Ar1 and Ar2 denote a carbon cyclic arom. ring group or heterocyclic arom. ring group, Z denotes a methylene group or ethylene group which is of a single bond or may have a substituent, or oxygen atom or sulfur atom-substd. amino group. The photosensitive body having the high sensitivity and the excellent potential stability during long-term use is thereby obtd. and the good image having no fogging is obtd. with high sensitivity even in the oscillation wavelength region of a semiconductor laser.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a novel electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor containing a tris-7zo pigment having a specific molecular structure in a photoconductive layer. Regarding the body.

[Prior Art] Pigments and dyes exhibiting photoconductivity have been published in numerous publications.

For example, “RCA Review” Vol. 23
, P., 413-P., 419 (1982, 9) have published on the photoconductivity of phthalocyanine pigments, and electrophotographic photoreceptors using these phthalocyanine pigments have been published in U.S. Pat. No. 3,397,086 and U.S. Pat. 3
It is described in Publication No. 816118 and the like. Other,
Examples of organic semiconductors used in electrophotographic photoreceptors include U.S. Pat. No. 4,315,983 and U.S. Pat. No. 43,271.
Publication No. 69” Ret@achDisclosures
” 20517 (1981, 5), methine squaric acid dyes described in U.S. Pat. No. 3,824,099, U.S. Pat. No. 3,898,084, U.S. Pat. No. 4,251,613, etc. Examples include disazo pigments.

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;
It has problems with sensitivity and durability.

[Problems to be Solved by the Invention] The purpose of the present invention is to provide a novel photoconductive material that can be used in all current electrophotographic processes, has practical high-sensitivity characteristics, and is suitable for repeated use. An object of the present invention is to provide an electrophotographic photoreceptor having stable potential characteristics.

[Means and effects for solving the problems] The present invention provides an electrophotographic photoreceptor having a photoconductive layer,
It is composed of an electrophotographic photoreceptor characterized in that the photoconductive layer contains a trisazo pigment represented by the following general formula (1).

General formula (1) In the formula, R1 and R2 represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, an alkoxy group, a halogen atom, or a cyano group,
R3 and R4 represent a hydrogen atom or an electron-withdrawing group, A represents a coupler residue having a phenolic hydroxyl group, and Ar1 and Ar2 represent a substituted or unsubstituted carbocyclic aromatic ring group or a heterocyclic aromatic ring. represents a group, Ar1
, Ar2 may be the same or different.

Z represents a single bond, a methylene group, an ethylene group, or an oxygen or sulfur atom-substituted amino group which may have a single bond or a substituent.

Specifically, R1 and R2 are methyl, ethyl, propyl, isopropyl, butyl, S-butyl.

Examples include groups such as t-butyl, methoxy, nidoxy, propoxy, phenoxy, phenyl, p-tolyl, benzyl, phenethyl, naphthylmethyl, fluorine atom, chlorine atom, iodine atom, bromine atom, and cyano. Halogen atoms such as fluorine, chlorine, bromine and iodine; alkyl groups such as methyl, ethyl, propyl and butyl; alkoxy groups such as methoxy, ethoxy, propoxy and phenoxy; nitro group, cyano group, dimethylamino and diethylamino , dibenzylamino, diphenylamino, or substituted amino groups such as morpholino, piperidino, and pyrrolidino.

Examples of the electron-withdrawing group for R3 and R4 include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, cyano group, and nitro group.

More preferable specific examples of the coupler residue having a phenolic hydroxyl group in A include residues represented by the following general formulas (2) to (8).

In the general formula, or when condensed with a benzene ring to form a polycyclic aromatic ring or a heterocyclic ring such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, dibenzonaphthofuran ring, diphenylene sulfide ring, etc. Required residues are indicated.

The ring to which X is bonded is more preferably a naphthalene ring, an anthracene ring, a carbazole ring, or a benzcarbazole ring.

R5 and R6 are a hydrogen atom, an alkyl group that may have a substituent, an aryl, an aralkyl group, a heterocyclic group, or R
5, represents a cyclic amino group together with the nitrogen atom to which R6 is bonded.

Specific examples of alkyl groups are methyl and ethyl.

Specific examples of propyl, butyl, and aralkyl groups include benzyl, phenethyl, naphthyl, and methyl; specific examples of aryl groups include phenyl, diphenyl, naphthyl, and anthryl; specific examples of heterocyclic groups include carbazole, dibenzofuran, Examples include thiazole and pyridish.

General formula
A specific example of 7, R8 is shown by the same example as the above-mentioned R5, Re.

The alkyl group, aryl group, aralkyl group, alkoxy group, and heterocyclic group represented by the substituents R5 to R8 in general formulas (2) to (4) may further include other substituents such as a fluorine atom, a chlorine atom, an iodine atom, Halogen atoms such as bromine atoms, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, alkoxy groups such as methoxy, ethoxy, propoxy, phenoxy, nitro groups, cyano groups, dimethyl 7
It may be substituted with a substituted amino group such as mino, dibenzylamino, diphenyl7mino, morpholino, piperidino, or pyrrolidino.

General formula, -Y-.

,・Y〜・.

In the formula, Y represents a divalent aromatic hydrocarbon group or a heterocyclic divalent group containing a nitrogen atom in the ring, and the divalent aromatic hydrocarbon group includes a monocyclic aromatic group such as 0-phenylene. divalent group of group hydrocarbons, 0-naphthylene, perinaphthylene, 1
．． Examples include divalent groups of condensed polycyclic aromatic hydrocarbons such as 2-7thrylene and 9.10-phenanthrylene, and examples of divalent groups of heterocycles containing a nitrogen atom in the ring include 3.4
-Pyrazolediyl group, 2,3-pyridinediyl group, 4
, 5-pyrimidinediyl 1,6.7-indazolediyl group, and 6.7-chiralindiyl group.

In the general formula, R9 represents an aryl group or a heterocyclic group which may have a substituent, specifically phenyl, naphthyl, anthryl, pyrenyl, pyridyl, chenyl, furyl, carbazolyl group, and an aryl group. Examples of substituents for the heterocyclic group include /\logen atoms such as fluorine atom, chlorine atom, iodine atom, and bromine atom, alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, methoxy,
Alkoxy groups such as ethoxy, propoxy, and phenoxy, nitro groups, cyano groups, dimethylamino, dibenzylamino, diphenylamino, and morpholino.

Examples include substituted amino groups such as piperidino and pyrrolidino.

X has the same meaning as X in the general formula (2).

"x'" In the formula, RIG and R11 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, specifically methyl, ethyl, propyl, butyl,
Benzyl, phenethyl, naphthylmethyl, phenyl, diphenyl, naphthyl, anthryl, carbazole, dibenzofuran, benzimidacilone, benzthiazole,
Thiazole and pyridine are shown, and substituents for alkyl groups, aryl groups, aralkyl groups, and heterocyclic groups include:
Halogen atoms such as fluorine, chlorine, iodine, and bromine atoms; alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy; nitro groups, cyano groups, and dimethylamino , dibenzylamino, diphenylamino, morpholino, piperidi/, pyrolisif and the like.

X has the same meaning as X in the general formula (2).

Ar1 and Ar2 in general formula (1) are specifically carbocyclic aromatic ring groups such as phenyl, naphthyl, and anthryl, or heterocyclic aromatic ring groups such as furyl, pyroyl, chenyl, pyridyl, and pyrazinyl. Substituents include halogen atoms such as fluorine, chlorine, iodine and bromine; alkyl groups such as methyl, ethyl, propyl, isopropyl and butyl; alkoxy groups such as methoxy, ethoxy, propoxy and phenoxy; and nitro groups. , cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, pyrroliscif and other substituted amino groups.

, Z in general formula (1), a methylene group which may have a substituent, a fluorine atom as a substituent of the ethylene group,
Halogen atoms such as chlorine atoms, iodine atoms, bromine atoms,
Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy, and cyano groups.
Examples of the substituent of the substituted amino group include alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, and heptalyl groups such as phenyl, naphthyl, and anthryl.

Next, a general method for producing the trisazo pigment used in the present invention will be explained.

The trisazo pigment represented by the general formula (1) has the following general formula (
The triamine represented by 9) is converted into a hexazonium salt using a conventional method such as sodium nitrite or nitrosyl sulfate, and then aqueous coupling is performed with the coupler component A, or the obtained hexazonium salt is converted into a stable salt such as a borofluoride salt. It can be synthesized by coupling in an organic solvent such as DMF.

[In the formula, R1 to R4, Ar1, Ar2 and Z have the same meanings as in general formula (1)] Typical specific examples of the trisazo pigment represented by general formula (1) of the present invention are listed below.

Exemplary Pigment (1) Exemplary Pigment (2) Exemplary Pigment (3) Exemplary Pigment (0 Exemplary Pigment (5) Exemplary Pigment (8) Exemplary Pigment (7) Exemplary Pigment (10) Exemplary Pigment (11) ○H0f-1 Exemplary Pigment (13) Exemplary Pigment (15) Exemplary Pigment (1 day) Exemplary Pigment (17) Exemplary Pigment (18) Exemplary Pigment (19) Exemplary Pigment (20), Exemplary Pigment (21) Exemplary Pigment (22) Exemplary Pigment (23) Exemplary Pigment (20) Exemplary Pigment (25) Exemplary Pigment (28) Exemplary Pigment (27) Exemplary Pigment (28) Exemplary Pigment (28) Exemplary Pigment (30) Exemplary Pigment (31) Exemplary Pigment (32) Exemplary Pigment (33) Exemplary Pigment Pigment (34) Exemplary class, pigment (35) Exemplary pigment (38) Exemplary pigment (37) Exemplary pigment (38) Exemplary pigment (33) Exemplary pigment (40) Exemplary pigment (41) Exemplary pigment (42) Exemplary pigment (43) ) Exemplary Pigment (44) Exemplary Pigment (45) Exemplary Pigment (46) Exemplary Pigment (47) The trisazo pigments shown in the above specific examples do not limit the scope of the claims of the present invention.

The coating with the aforementioned trisazo pigment exhibits photoconductivity;
Therefore, it can be used in the photosensitive layer of an electrophotographic photoreceptor.

That is, in a specific example of the present invention, an electrophotographic photoreceptor is prepared by forming a film of the above-mentioned trisazo pigment on a conductive support by vacuum evaporation, or by forming a film by dispersing the trisazo pigment in a suitable binder. can do.

In a preferred embodiment of the present invention, the photoconductive coating described above can 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.

The charge generation layer contains as much of the above-mentioned photoconductive compound as possible in order to obtain sufficient light absorption, and is preferably a thin film layer, for example, 51 Lm or less, in order to shorten the range of the generated charge carriers. It is preferable to form a thin film layer having a thickness of 0.0, O1 to 1 μm.

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 by dispersing the trisazo pigment in a suitable binder and coating it on a substrate, or can be obtained by forming a deposited film using a vacuum deposition apparatus. The binder that can be used to form the material 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, polyurethane, epoxy resin Examples include insulating resins such as casein, polyvinyl alcohol, and polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80ii1% or less, preferably 40% by weight 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
, amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol 7-methyl ether;
Esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, or benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. aromatic hydrocarbons and the like can be used.

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

When the charge transport layer is formed on the charge generation layer, charge transport materials include electron transport materials and hole transport materials.
Examples of electron-transporting substances include chloranil, bromoanil,
Tetracyanoethylene, tetracyanoquinodimethane, 2
, 4.7-1 linitro-9-fluorenone, 2,4,5
．． 7-tetranitro-9-fluorenone, 2,4.7-
Examples include electron-withdrawing substances such as dolinitro-9-dicyanomethylenefluorenone, 2°4.5.7-titranitroxanthone, and 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-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ditylphenothiazine, N, N-diphenylhydrazino-3-methylidene-
10-Nitylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N
-Hydrazones such as phenylhydrazone, 2,5-bis(p-diethylaminostyryl)-1,3,4-oxadiazole, 1-phenyl-3-(p-diethyl7minostyryl)-5-(p-diethylaminostyryl) phenyl)pyrazoline, 1-[quinolyl(2)]-2-(p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-
3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-phenyl-3-
(p-diethylaminostyryl)-4-methyl-5-(
p-diethylaminophenyl) hilazoline, l-phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline,
Pyrazolines such as spiropyrazoline, 2-(p-diethylaminostyryl)-6-dinithylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-
Oxazole compounds such as (p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2
-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole and other thiazole compounds, bis(
Tri7lylmethane compounds such as 4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethyl7mino-2-methylphenyl)hebutane, 1,1,2 .2-tetrakis(4-N,N
-Polyarylalkanes such as dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-
N-vinylcarbazole, polyvinylpylene, polyvinylanthracene, polyvinyl 7-crisine, poly-9-
Examples include vinylphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin.

In addition to this organic charge transport material, selenium, selenium-tellurium,
Inorganic materials such as 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. What resins can be used as binders?

For example, acrylic resin, polyarylate, polyester,
Polycarbonate, polystyrene, acrylonitrile
Styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide,
Examples include insulating resins such as chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

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 gm, but the preferred range is 8 to 201 gm.
It is Lm. 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 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, molyftene, 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 61o, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. . The appropriate thickness of the undercoat layer is 0.1 to 5 #Lm, preferably 0.5 to 3 pm.

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 electrically charged. During post-exposure, 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 charges, causing a decrease in surface potential and creating static between the exposed area and the unexposed area. Electrocontrast 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 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. After that, it reaches the surface and neutralizes the negative charge, 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 when an electron transporting substance is used.

When using an electrophotographic photoreceptor in which a conductive layer, a charge transport layer, and a charge generation layer are laminated in this order, when the charge transport substance is an electron transport substance, the surface of the charge generation layer must be negatively charged; When exposed after exposure, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area.
Then it reaches the substrate. On the other hand, holes generated in the charge generation layer reach the surface, attenuation of the surface potential occurs, and electrostatic contrast occurs between the layer and the unexposed area. A visible image is 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 visually imaged and fixed after being transferred to paper or plastic film.

On the other hand, when the charge generation layer is made of a hole transport substance, the surface of the charge generation layer must be positively 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. and then reaches the substrate. On the other hand, electrons generated in the charge generation layer reach the surface and are attenuated by about one surface quantity, 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, organic photoconductive materials such as the aforementioned hydrazones, pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamine, poly-N-vinylcarbazoles, etc. The photosensitive coating may contain a trisazo pigment represented by the general formula (1) as a sensitizer for inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. This photosensitive film is formed by coating these photoconductive substances and the trisazo pigment together with a binder.

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

At this time, a charge transfer complex compound consisting of poly-N-vinylcarbazole and trinitrofluorenone can be used in addition to the above-mentioned charge transport substance.

The electrophotographic photoreceptor of this example was prepared after the aforementioned trisazo pigment and charge transfer rust compound were dispersed in a polyester solution dissolved in tetrahydrofuran.

Can be created by forming a film.

The pigment used in any electrophotographic photoreceptor 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. good.

In addition, if necessary, pigments with different light absorptions may be used in combination to increase the sensitivity of the photoreceptor, or two or more types of trisazo pigments represented by general formula (1) may be combined for the purpose of obtaining a panchromatic photoreceptor. Alternatively, it can 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 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 laser engraving.

[Example] Examples 1 to 25 Ammonia aqueous solution of casein (casein 1
1.2%, ammonia water 1g, water 222mal) after drying with a Mayer bar, the film thickness is 1. It was coated to give OILm and dried.

Next, 5 g of the exemplary pigment (1) was added to 95 ra of ethanol.
2 g of butyral resin (degree of butyralization 63 mol%) for n
was added to the dissolved solution and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed casein layer using a Mayer bar so that the film thickness after drying was 0.54 m. After drying, a charge generating layer was formed using 5 g of a hydrazone compound and polymethyl methacrylate (number average molecular weight 100,000) was dissolved in 70 ml of benzene, and this was applied onto the charge generation layer using a Mayer bar so that the film thickness after drying was 127 zm, and dried to form a charge transport layer. An electrophotographic photoreceptor was created.

Examples 2 to 2 using other exemplary pigments in place of exemplary pigment (1)
An electrophotographic photoreceptor corresponding to No. 5 was prepared in exactly the same manner.

The electrophotographic photoreceptor produced in this way was statically tested using an electrostatic copying paper tester (SP-428).
After corona charging with KV and holding for 1 second in the dark, the illumination intensity was 2.
It was exposed to lux light and its charging characteristics were examined.

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

S V -V El/2 1LIX 5ea1
(1) 600 4.52
(2) , 620 2.83
(a) 610 2.64
(8) 605 3.05
(7) 620 3.56 (
9) 610 4.07 (11
) 610 4.38 (13
) 610, 3.59 (14
) 620 3.910 (15
) 600 4.211 (16
) 610 3.612 (1
7) 620 3.41 3 (1
9) 61o 3.614
(21) 610 3.115
(22) 620 3.016
(23) 600 3.517
(24) 600 3.218
(213) 600 3.619
(3G) 620 3.020
(38) 800 3.521
(37) 610 4.222
(40) 600 4.123
(42) 810 4.624
(43) 610 3.525
(44) 615 3.8 Furthermore, using the electrophotographic photoreceptor used in Example 2.9.11.15, fluctuations in bright area potential and dark area potential were measured when the shuttle was used repeatedly.

As a method, the photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a -5.6 KV corona charger, an exposure optical system, a developer, 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 copier, the initial bright area potential (VL) and dark area potential (Vo) were set to around lt, -Pray-100V, -600V, and the bright area potential (VL) after 5,000 uses was set.
) and dark potential (To ) were measured.

The results are shown below.

2 600 Zoo 603 10
311 Boo Zoo 603
103 Example 26 5 g of 2.4° 7-dolinitro-9-fluorenone and 5 g of poly-4,4-dioxydiphenyl-2,2-propane carbonate (molecular weight: 300,000) were placed on the charge generation layer formed in Example 2. A coating solution prepared by dissolving the above in 70 tml of tetrahydrofuran was applied and dried so that the coating amount after drying was 10 g 7 m 2 .

The electrostatic charge of the electrophotographic photoreceptor thus prepared was measured in the same manner as in Example 1. The charging polarity at this time was set to 10. Show the results.

vo: +590V, El/2: 4.1iux, see Example 27 Trisazo pigment used in Example 2, in which a polyvinyl alcohol film with a thickness of 0.5 Bm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film. The dispersion was applied onto the previously formed polyvinyl alcohol layer using a Mayer bar so that the film thickness after drying was 0.5 lm, and dried to form a charge generation layer.

5 g of pyrazoline compound and 5 g of polyarylate (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid)
was dissolved in 70 til of tetrahydrofuran, and a solution was applied onto the charge generation layer so that the film thickness after drying was 10 lm, and dried to form a charge transport layer. The charging characteristics and durability characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

Vo knee 810V, E 1/2: 2.91ux, sea Initial durability characteristics Vo knee 600V, VL knee 100V 5,000 V D: -601V, V L: -103V As the above results show, the sensitivity is also good. The potential stability during long-term use is also good.

Example 28 An ammonia aqueous solution of casein was applied onto an aluminum plate having a thickness of 100 JLm and dried to form a subbing layer of 0.5 gm.

Next, 2.4.7-) 5 g of Leetlow 9-fluorenone and poly-N-vinylcarbazole (number average molecular weight 300,000)
A charge transfer complex compound was prepared by dissolving 5 g in 7°II of tetrahydrofuran.

This charge transfer complex compound and 1 g of the above-mentioned exemplary pigment (14) were added to and dispersed in a solution in which 5 g of polyester resin was dissolved in 7 ors of tetrahydrofuran.

This dispersion was applied onto the undercoat layer and dried to a film thickness of 12JL.
It was set as m.

The charging characteristics of the produced electrophotographic photoreceptor were measured in the same manner as in Example 1. However, the charging polarity was set to 10. Show the results.

V□: +600V.

El/2: 4.2 Jlux, sec Example 29 A charge transport layer and a charge generation layer similar to those in Example 2 were sequentially laminated on the casein layer of the aluminum base coated with the casein layer used in Example 28 to obtain a layer structure. A photoreceptor was prepared in the same manner except for the following differences.

Charging characteristics were measured in the same manner as in Example 1.

However, the charging polarity was set to 10.

VO: +630V.

El/2: 2.9uux, see Example 30 The photoreceptor used in Example 15 [Example Pigment (22)] was
When exposed to light using a semiconductor laser with an oscillation wavelength of 80 nm, the spectral sensitivity at 780 nm was 2.1 pJ/
cm2 (half-decreased exposure amount). Next, this photoreceptor was printed on a laser beam printer (LBP-
When the image was formed on a CX drum and a live photographing test was conducted, a good image without fogging was obtained. Also, this did not change even after turning the tree over 10,000 times.

Examples 31 to 34 Exemplary pigments (12), (19), (26) and (34) were used in place of exemplary pigment (22) used in Example 30.
A drum-shaped photoreceptor was prepared in the same manner except that the trisazo pigment was used.

The spectral sensitivity of each photoreceptor at 780 nm was as follows.

Examples Illustrative pigment Half-decreased exposure amount (J/cm2), 31
(12) 2.032 (19)
2.2 33 (2fl) 2.034' (
34) 2.5 Next, an actual photographic test was conducted in the same manner as in Example 30, and a fog-free image was obtained, which did not change even after repeating this 10,000 times.

[Effects of the Invention] The electrophotographic photoreceptor of the present invention uses a specific trisazo pigment in the photosensitive layer, so that either or both of carrier generation efficiency and carrier transport efficiency within the photosensitive layer containing the trisazo pigment is improved. It has high sensitivity and excellent potential stability during long-term use, and has the remarkable effect of being able to obtain good images without fog with high sensitivity even in the oscillation wavelength range of semiconductor lasers. play.

Claims (8)

[Claims] (1) An electrophotographic photoreceptor having a photoconductive layer, characterized in that the photoconductive layer contains a trisazo pigment represented by the following general formula (1). General formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, R_1 and R_2 are hydrogen atoms, alkyl groups that may have substituents, aryl groups, aralkyl groups, alkoxy groups, halogen atoms, or cyano groups , R_3 and R_4 represent a hydrogen atom or an electron-withdrawing group, A represents a coupler residue having a phenolic hydroxyl group, and Ar_1 and Ar_2 represent a substituted or unsubstituted carbocyclic aromatic ring group or a heterocyclic group. It represents an aromatic ring group, Ar_1 and Ar_2 may be the same or different, and Z represents a single bond or a methylene group, ethylene group, or an oxygen atom or sulfur atom substituted amino group which may have a single bond or a substituent. show. (2) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (2). General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(2) In the formula, It represents a cyclic amino group together with an alkyl group, an aryl group, an aralkyl group, a heterocyclic group, or the nitrogen atom to which R_5 and R_6 are bonded, which may have a group. (3) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (3). General formula ▲There are numerical formulas, chemical formulas, tables, etc.▼ (3) In the formula, R_7 represents an alkyl group, an aryl group, or an aralkyl group that may have a substituent. (4) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (4). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (4) In the formula, R_8 represents an alkyl group, aryl group, or aralkyl group that may have a substituent. (5) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (5). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (5) In the formula, Y represents a divalent aromatic hydrocarbon group or a heterocyclic divalent group containing a nitrogen atom in the ring. (6) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (6). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (6) In the formula, Y represents a divalent aromatic hydrocarbon group or a heterocyclic divalent group containing a nitrogen atom in the ring. (7) The electrophotographic photoreceptor according to claim 1, wherein A in general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (7). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (7) In the formula, R_9 represents an aryl group or a heterocyclic group that may have a substituent, and X has the same meaning as X in the general formula (2) above. It is. (8) The electrophotographic photoreceptor according to claim 1, wherein A in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (8). General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(8) In the formula, R_1_0 and R_1_1 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group that may have a substituent, and X is the general formula shown above. It has the same meaning as X in (2).