JPH0247663A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve high sensitivity, durability and above all, potential stability at the time of durable use by using a specific disazo pigment in a photosensitive layer. CONSTITUTION:The disazo pigment expressed by formula I is incorporated into the photosensitive layer formed on a conductive base. In formula I, A, A' denote a residual coupler group having a phenolic hydroxyl group. The electrophotographic sensitive body which is stable to heat and light and has excellent carrier generating power is obtd. in this way and is usable in all existing electrophotographic processes. The practicably high sensitivity and the stable potential characteristic in repetitive use are thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a disazo pigment having a specific molecular structure in a photosensitive layer.

[Prior Art J Electrophotography, as disclosed in U.S. Pat. No. 2,297,691, involves coating an insulating material in the dark whose electrical resistance changes depending on the amount of radiation received during image exposure. A photoconductive material consisting of a support is used.

The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material are (1) ability to be charged to an appropriate potential in a dark place, (2) low charge dissipation in a dark place, (3) Examples include scales that quickly dissipate charge when irradiated with light.

Conventionally, electrophotographic photoreceptors have been made of selenium, #zinc,
Inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound as a main component, such as cadmium sulfide, have been widely used. However, although these satisfy the conditions (1) to (3) above, they do not necessarily satisfy the conditions such as thermal stability, moisture resistance, and durability.For example, when selenium crystallizes, its properties as a photoreceptor deteriorate. It is difficult to manufacture because it deteriorates, and it also crystallizes due to heat and fingerprints, deteriorating its performance as a photoreceptor. Cadmium sulfide has poor moisture resistance and durability, while zinc oxide has poor smoothness, hardness, and durability. There is a problem with friction.

Furthermore, many inorganic photoreceptors have a limited photosensitive wavelength range. For example, selenium is sensitive to blue wavelengths and has almost no sensitivity in the red region. Various methods have been proposed, but there are many restrictions on the selection of the sensitive wavelength range. Even when zinc oxide or cadmium sulfide is used as a photoreceptor, the sensitive wavelength range itself is narrow, and the addition of various sensitizers is required. is necessary.

In order to overcome these drawbacks of inorganic photoreceptors, electrophotographic photoreceptors containing various organic photoconductive compounds as main components have been actively developed in recent years.

For example, Japanese Patent Publication No. 50-10496, U.S. Patent No. 34
No. 84237 describes a photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2.4.7-)dinitrofluorenone-9-one, a photoreceptor in which poly-N-vinylcarbazole is sensitized with a biryllium base dye. (Japanese Patent Publication No. 48-25658).

Although these organic electrophotographic photoreceptors have improved the drawbacks of the inorganic electrophotographic photoreceptors to some extent, they generally have low photosensitivity and are not suitable for repeated use.

In order to overcome these drawbacks, various photoreceptors have been proposed as organic electrophotographic photoreceptors in recent years. ) and a charge-transporting layer (charge-transporting material) that accepts and transports generated charge carriers (charge-generating layer). Some of them are in practical use because they generally have high sensitivity and can withstand repeated use.

For example, JP-A-60-111249 and JP-A-61-1 disclose photoreceptors using azo pigments as charge-generating substances.
Publication No. 8205 and the like are already known. However, when these azo pigments are used, they do not necessarily satisfy the characteristics of sensitivity or stability during repeated use, and the selection range of charge transport materials is also limited, making it difficult to meet the wide demands of electrophotographic processes. It's not quite satisfying.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel photoconductive material;
To provide an electrophotographic photoreceptor containing a specific disazo pigment that is stable against heat and light and has excellent carrier generation ability, and which can be used in all current electrophotographic processes and is a practical high-performance material. An object of the present invention is to provide an electrophotographic photoreceptor that has good sensitivity and stable potential characteristics during repeated use.

[Means for Solving the Problems 1 Effect] The present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photoconductive layer contains a disazo pigment represented by the following general formula (1). It consists of an electrophotographic photoreceptor.

General formula % Formula % (1) In the formula, A and A' represent coupler residues having a phenolic hydroxyl group.

More preferred specific examples of the coupler residues having a phenolic hydroxyl group represented by A and A' in the general formula (1) include residues represented by the following general formulas (2) to (6).

'x' In the formula, X is fused with a benzene ring to form a polycyclic aromatic ring or heterocycle such as a naphthalene ring, anthracene ring, carbazole ring, benzcarbazole ring, dibenzofuran ring, dibenzonaphthofuran ring, or diphenylene sulfide ring. The fused ring of X is more preferably a naphthalene ring, anthracene ring, carbazole ring, or benzcarbazole ring.

R1 and R2 are a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, a heterocyclic group, or R
1, indicates a cyclic amine group containing a nitrogen atom to which R2 is bonded in the ring; alkyl groups include methyl, ethyl, propyl, butyl, etc., 7-aryl groups include phenyl, diphenyl, naphthyl, anthryl, etc. Aralkyl groups include benzyl, phenethyl, naphthylmethyl, etc.; heterocyclic groups include carbazole, dibenzofuran,
Benzimidacilone, benzthiazole.

Examples include groups such as thiazole and pyridine.

Examples include alkoxy groups such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino substituted amine groups.

In the formula, R3 represents a hydrogen atom, a furkyl group, an aryl group, or an aralkyl group which may have an R substituent. Specific examples of R3 are shown by the same examples as for R, and R2 described above.

Examples of optional substituents of the alkyl group, aryl group, aralkyl group, alkoxy group, and heterocyclic group represented by R1 to R3 in general formulas (2) and (3) include a fluorine atom, a chlorine atom, and an iodine atom. atom, a halogen atom such as a bromine atom, an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, methoxy, ethoxy, propoxy, or phenoxy, where Y is a divalent group of aromatic hydrocarbon or a nitrogen atom in the ring. The divalent groups of aromatic hydrocarbons include divalent groups of monocyclic aromatic hydrocarbons such as O-phenylene, 0-naphthylene, berinaphthylene, 1,2- Anthrylene 9. Divalent groups of fused polycyclic aromatic hydrocarbons such as 10-phenanthrylene are mentioned,
As a heterocyclic divalent group containing a nitrogen atom in the ring, 3,
4-pyrazolediyl group, 2,3-pyridinediyl group 4
．． Divalent groups such as 5-pyrimidinediyl group, 6.7-indazolediyl group, and 6.7-chiralindiyl group can be mentioned.

In the formula ゛.

Furthermore, substituents for aryl groups and heterocyclic groups include halogen atoms such as fluorine, chlorine, iodine and bromine, alkyl groups such as methyl, ethyl, propyl isopropyl and butyl, methoxy, nidoxy, propoxy and phenoxy. Alkoxy group, nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino,
Examples include substituted amine 7 groups such as morpholino, piperidino, and pyrrolidino.

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

p.

In the formula, R5 and R6 represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group which may have a substituent, and specifically examples of the alkyl group include methyl, ethyl, propyl, butyl, Examples of aralkyl groups include benzyl, phenethyl, naphthylmethyl, aryl groups include phenyl, diphenyl, naphthyl, anthryl, and heterocyclic groups include carbazolyl, thienyl, pyridyl, furyl, etc. Furthermore, alkyl groups, aralkyl groups, Substituents for aryl groups and heterocyclic groups include halogen atoms such as fluorine atom, chlorine atom, iodine atom, and bromine atom, alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, methoxy, ethoxy, propoxy,
Alkoxy groups such as phenoxy, nitro groups, cyano groups,
Substituted amines such as dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, pyrolisif, etc.
Examples include groups.

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

X' In the formula, R7 and R8 represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group which may have a substituent, and specifically, the alkyl group includes methyl, ethyl, propyl, Butyl.

Aralkyl groups include benzyl, phenethyl, and naphthylmethyl; aryl groups include phenyl, diphenyl, naphthyl, and anthryl; and heterocyclic groups include power! Examples include groups such as rebazolyl, thienyl, pyridyl, and furyl, and substituents for alkyl groups, aralkyl groups, aryl groups, and heterocyclic groups include halogen atoms such as fluorine atoms, chlorine atoms, iodine atoms, and bromine atoms; Alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl; alkoxy groups such as methoxy, nidoxy, propoxy, and phenoxy; substituted amino groups such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino; Examples include groups.

Z represents an oxygen atom or a sulfur atom.

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

Next, a general method for producing the disazo pigment represented by the general formula (1) used in the present invention will be described.

In general formula (1), when A and A' are the same.

The diamine represented by the following general formula (8) is HAM-@-C(cN)-C(CN)-@-MHI
(a) Prepare a tetrazonium salt by a conventional method using sodium nitrite or nitrosyl sulfuric acid, etc., and perform aqueous coupling with the couplers A and A', or convert the obtained tetrazonium salt into a stable salt such as a borofluoride salt. After conversion, it can be easily synthesized by coupling with a corresponding coupler in an organic solvent such as N,N-dimethylformamide or dimethyl sulfoxide.

If A and A' are different, in the coupling reaction, first couple with the first coupler to form a monoazo pigment, and then couple with the second coupler to form a disazo pigment, or, It can be obtained by mixing two couplers and performing a coupling reaction.

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

However, these disazo pigments do not limit the scope of the claims of the present invention.

The description will show only A and A' that change in the basic type.

Basic type A-N-N-o-C (ON)-C (CM) building N-N-A
'Exemplary Pigment (1) Exemplary Pigment (4) Exemplary Pigment (5) Exemplary Pigment (6) Exemplary Face $4 (2) Exemplary Pigment (7) Exemplary Pigment (3) Exemplary Pigment (8) Exemplary Pigment (9) Exemplary Pigment (13) Exemplary Pigment (10) 8 Exemplary Pigment (14) Exemplary Pigment (11) Shisu Exemplary Pigment (15) Exemplary Pigment (12) C! Exemplary Pigment (16) Exemplary Pigment (17) Exemplary Pigment (18 ) The film containing the disazo pigment represented by the above-mentioned general formula (1) exhibits photoconductivity, and therefore can be used in the photosensitive layer of an electrophotographic photoreceptor.

That is, in the present invention, the above-mentioned general formula (1) is formed on a conductive support.
An electrophotographic photoreceptor can be constructed by forming a film using the disazo pigment represented by the following by a true zI vapor deposition method, or by dispersing and containing the disazo pigment in a suitable binder to form a film.

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 disazo pigment as possible in order to obtain sufficient absorbance, and a thin film layer, e.g. m or less, preferably 0.0l-1u, m
It is desirable to form a thin film layer with a thickness of .

As mentioned above, the charge generation layer can be formed, for example, by dispersing the disazo pigment represented by the general formula (1) in a suitable binder and coating it on a conductive substrate. can be obtained by forming .

The binder that can be used to form 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. Preferred are polyvinyl butyral and polyvinyl benzal.

Polyarylate (1i1 of bisphenol A and 7-talic acid)
ffi coalescence, etc.), polycarbonate, polyester,
Examples include insulating resins such as phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin casein, polyvinyl alcohol, and polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of 811 resin, and is preferably selected from those that do not dissolve the underlying charge transport layer or subbing layer.

Specific organic solvents include alcohols such as methanol, ethanol, and impropatol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and dichlorohexanone, and N,N-dimethylformamide and N,N-dimethylacetamide. Amides, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofurandioxane and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, fats such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Group halogenated hydrocarbons or aromatics such as benzene, toluene, xylene, ligroin monochlorobenzene, dichlorobenzene, etc. can be used.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Meyer bar coating method, blade coating method,
Roller coating method.

This can be carried out using a coating method such as a curtain coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry.Heat drying is performed at a temperature of 30 to 200°C for 5 minutes to 2 minutes.
It can be carried out stationary or under ventilation for a range of 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 a side farther from the charge generation layer when viewed from the conductive support, or may be located between the conductive support and the charge generation layer.

Charge-transporting substances include electron-transporting substances and hole-transporting substances, and electron-transporting substances include chloranil, bromoanil, tetracyanoethylenetetracyanoquinodimethane, 2,4.7-)linitrile-9-fluorenone, 2 ，
4,5.7-tetranitro-9-fluorenone, 2,4
．． 7-dolinitro 9-dicyanomethylenefluorenone, 2.4,5.7-tetranitroxanthone, 2°4.
Examples include electron-withdrawing substances such as 8-trinidrothioxanthone, and polymerization of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, and 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-Ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N
-7enylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3.3-)rifthylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-diethylbenzaldehyde-3-
Hydrazone compounds such as methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl-3-(p-diethylaminostyryl)- 5-(p-
diethylaminophenyl)pyrazoline, 1-[quinolyl(2)]-3-(p-diethylaminostyryl)-5
-(p-jethylaminophenyl)pyrazoline, 1-[
pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline,
1-[6-medoxypyridyl(2)]3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(3)]-3-(
p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[lepidyl (2)]-
3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-[pyridyl(2
)]-3-(p-diethylaminostyryl-4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1
-[Pyridyl (2)] -3-(α-Methyl-P-diethylaminostyryl)-5-(p-diethylaminophenyl 1-phenyl-3-(p-diethylaminostyryl)-
Pyrazoline compounds such as 4-methyl-5-(p-diethylaminophenyl)pyrazoline, l-phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline, α- Phenyl-4-N,N-diphenylaminostilbene, N-ethyl-3-(α-phenylstyryl)carbazole, 9-P-dibenzylaminobenzylidene-9H-fluorenone, 5-p-ditolylaminobenzylidene-5H- Styryl compounds such as dibenzo[a,d]cycloheptene, 2-(P-diethylaminostyryl)-6-dinithylaminobenzoxazole, 2
Oxazole compounds such as -(P-diethylaminophenyl)-4-(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole, etc. Thiazole compounds, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)phenylmethane 1,1-bis(4-N,N-
diethylamine-2-methylphenyl)hebutane, 1,
1,2.2tetrakis(4-N,N-dimethylamino-
Polyarylalkane compounds such as 2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylanthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin Examples include.

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 copolymer,
Examples include insulating resins such as acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. .

The charge transport layer has a limit to its ability to transport charge carriers, so it cannot be made thicker than necessary. - For boat fishing, it is 5 to 40 pm, but the preferred range is 15 to 3 pm.
0 gm. 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 support having, for example, a conductive layer as a conductive support.

As the conductive support, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum chromium, titanium, nickel, indium, gold, platinum, etc. can be used, and the support itself is conductive.
In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, ,
Polyfluorinated ethylene, etc.), a support made of conductive particles (e.g. carbon black, silver particles, etc.) coated on plastic with a suitable binder, a support made of plastic or paper impregnated with conductive particles, or a conductive polymer. Plastic or the like can be used.

A subbing layer having a barrier function and an adhesive function can also be provided between the conductive layer and the photosensitive layer. The undercoat layer is made of cold water,
Polyvinyl alcohol, nitrocellulose, ethylene-
It can be formed from acrylic acid copolymers, polyamides (nylon 6, nylon 66, nylon 610, copolymerized nylons, alkoxymethylated nylons, etc.), polyurethane, gelatin, aluminum oxide, and the like.

The thickness of the undercoat layer is 5 #Lm or less, preferably 0.1 to 3
Le m is appropriate.

When using a photoreceptor in which a conductive support, 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. During post-exposure, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then
It reaches the surface and neutralizes the positive charge, causing a decrease in the surface potential.
Electrostatic contrast occurs between the exposed area and the unexposed area.

A visible image is obtained by developing the electrostatic latent image thus formed with a negatively charged toner. Fix this directly or
Alternatively, the toner image can be transferred to paper or plastic film, developed, and fixed.

After transferring the electrostatic latent image on the photoreceptor to the insulating layer of transfer paper,
A method of developing and fixing can also be used. The type of developer, developing method, and fixing method may be any known developer or known method, and are not limited to a specific one.

On the other hand, when the charge transport material is made of a hole transport material, it is necessary to charge the surface of the charge transport layer negatively, and after charging, when exposed to N light, 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 an attenuation of the surface potential and an electrostatic contrast with 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 support, a charge transport layer, and a charge generation layer are arranged in this order.When the charge transport material consists of 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 are injected into the charge transport layer in the exposed area, and then reach the conductive support.

On the other hand, holes generated in the charge generation layer reach the surface and the surface potential is attenuated, creating electrostatic contrast with the unexposed area.

A visible image is obtained by developing the electrostatic latent image thus formed with a positively charged toner. Fix this directly or
Alternatively, the toner image can be transferred to paper or plastic film, developed, and fixed.

After transferring the electrostatic latent image on the photoreceptor to the insulating layer of transfer paper,
A method of developing and fixing can also be used. The type of developer, developing method, and fixing method may be any known developer or known method, and are not limited to a specific one.

On the other hand, when the charge transport material is a hole transport material, it is necessary to positively charge the surface of the charge generation layer, and when exposed to light after charging, the holes generated in the charge generation layer become charged in the exposed area. It is injected into the transport layer and then reaches the conductive substrate.

On the other hand, the electrons generated in the charge generation layer reach the surface,
Attenuation of the surface potential occurs, 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.

In other specific examples of the present invention, the aforementioned hydrazone compounds, pyrazoline compounds, styryl compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, polyarylalkane compounds, triphenylamines, poly- A photosensitive film containing a disazo pigment represented by the above-mentioned general formula (1) as a sensitizer for organic photoconductive substances such as N-vinylcarbazole compounds and S-type conductive substances such as zinc oxide, cadmium sulfide, and selenium. It can be done. This photosensitive film is formed by coating these photoconductive substances and the above-mentioned general disazo pigment shown in 2) together with a binder.

Furthermore, the electrophotographic photoreceptor of the present invention may include an electrophotographic photoreceptor containing a disazo pigment represented by the above-mentioned general formula (1) together with a charge transport substance in the same layer. In addition, a charge transfer complex compound consisting of poly-N-vinylcarbazole and trinitrofluorenone can be used.

The electrophotographic photoreceptor of this example is manufactured by dispersing the disazo pigment represented by the general formula (1) and the charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a film thereon.

The pigment used in any of the electrophotographic photoreceptors contains at least one pigment selected from disazo pigments represented by the general formula (1), and its crystal form may be either amorphous or crystalline.

In addition, if necessary, two or more types of disazo pigments represented by the general formula (1) may be used in combination for the purpose of increasing the sensitivity of the photoreceptor by using a combination of pigments with different light absorptions, or obtaining a bank chromatic 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 in electrophotographic copying machines, laser beam printers, CRT printers, L
It can also be widely used in electrophotographic applications such as ED printers, liquid crystal printers, and laser engraving.

[Example] Example 1-13 0.0% on an aluminum plate. An undercoat layer made of a vinyl chloride-maleic anhydride-vinyl acetate copolymer of IILm was provided.

Next, 5 g of the above-mentioned exemplary pigment (1) was added to 95 g of cyclohexanone.
Butyral resin (butyralization degree 63 mol%,
It was added to the solution in which 2 g of the product (number average molecular weight: 20,000) was dissolved, and dispersed in a sand mill for 20 hours. This dispersion was applied onto the previously formed subbing layer using a Mayer bar so that the film thickness after drying was 0.5 JLm, and dried to form a charge generation layer.

Next, p-diethylaminobenzaldehyde-N-α-
5 g of naphthyl-N-phenylhydrazone, 5 g of polymethyl methacrylate (number average molecular weight 100,000), and polymethyl methacrylate (number average molecular weight 100,000) were dissolved in 70 rnfL of chlorobenzene, and this solution was placed on the charge generation layer after drying. It was coated with a Mayer bar to a film thickness of 20 gm and dried to form a charge transport layer. In this way, the electrophotographic photoreceptor of Example 1 was produced.

Example 2 was prepared by using the following example pigment in place of example pigment (1) used in Example 1, and using the same conditions as Example 1 except for the example pigment (1) used in Example 1.
Electrophotographic photoreceptors corresponding to items 1 to 13 were prepared.

The electrophotographic photoreceptor thus prepared was tested using an electrostatic copying paper tester (Kawaguchi Denki M Od 6 S, P-428).
) was statically charged with corona at -5.5 KV, held in a dark place for 1 second, and then exposed to light at an illuminance of 2 lux to examine charging characteristics.

The charging characteristics include the surface potential (Vo) and the amount of light exposure (El) required to attenuate the potential to 172 when dark decaying for 1 second
/2) was measured. Show the results.

V −V El/2 1u scl
(1) 690 2.52 (2)
695 2.13 (3)
690 3.04 (4) 700
3.85 (5) 700 2.8
6 (6) 695 2.57
(7) 690 2.38 (8)
695 1.89 (9) 6
80 3.010 (10) 695
1.111 (11) 695
1.812 (12) 70
0 1.913 (13)
700 1.6 ゛Comparative Examples 1 to 4 In place of the exemplary pigment (1) used in Example 1, JP-A-54-
7428, JP 56-116040, JP 59-129857, and JP 61-22
A photoreceptor was prepared in exactly the same manner as in Example 1 except for using an azo pigment represented by the following structural formula described in Publication No. 34, and evaluated in the same manner. Show the results.

In the case of comparative material 1 (Comparative Example 8) In the case of Comparative Azo Pigment Comparative Example 2 (Comparative Example 1) Comparative Azo Pigment vo Knee 690V El/2: 3.89. ux, sec For Comparative Example 3 (Comparative Example 3) Comparative Azo Pigment vo Knee 695V E 1/2: 2, 91 u X
, S e Qvo : -700V El/2: 6.61ux, sec Case of Comparative Example 4 (Comparative Example 7) Comparative azo pigment vo knee 700V El/2: 4.51ux, S ee Example 14 Example 1 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 dissolved in 70 ml of tetrahydrofuran on the charge generation layer formed in The coating solution prepared in this way was applied to the coating in a dry coating amount of 10 g/m2 and dried.

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

The charging polarity at this time was +. Show the results.

Vo: +690V El/2: 2.0Jlux, sec Examples 15 to 18 Using the electrophotographic photoreceptors prepared in Examples 1, 8, 10, and 13, fluctuations in bright area potential and dark area potential during repeated use were measured. did.

The measurement method was to attach a photoreceptor 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 -200V and -700V, and the bright area potential (VL) after 5,000 uses was set.
) and dark potential (Vo) were measured. Show the results.

From the above results, it can be seen that the sensitivity is good and the potential stability during long-term use is also good.

Example 19 A polyvinyl alcohol film having a thickness of 0.5 ILm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

Next, a dispersion of the disazo pigment (exemplary pigment (2) used in Example 2) was applied onto the polyvinyl alcohol layer formed earlier using a Mayer parr so that the film thickness after drying was 0.5 lm. The mixture was dried to form a charge generation layer.

A solution prepared by dissolving 5 g of benzylidene compound and 5 g of bisphenol Z type polycarbonate (viscosity average molecular weight FF 130,000) in 32.5 mJL of chlorobenzene was applied onto the charge generation layer so that the dry film thickness was 20 pm, and dried. A charge transport layer was formed.

Example 1 Charging characteristics of the electrophotographic photoreceptor thus prepared
And it was measured in the same manner as in Example 15. Show the results.

Vo knee 700V, El/2: 1.71ux, sec -1 Vo knee 700V VL knee 200 mj'' (6-6
A methanol solution of 6-610-12 quaternary nylon copolymer) was applied and kept dry to form a subbing layer with a film thickness of 0.5 m.

Next, 5 g of 2,4.7-dolinitro-9-fluorenone
and poly-N-vinylcarbazole average molecular weight 300,000) 5g
was dissolved in 70 ml of tetrahydrofuran to form a charge transfer complex.

1 g of this charge transfer complex compound and the exemplary pigment (lO) were mixed with polymethyl methacrylate-styrene copolymer (molecular weight 25
1,000) was added to a solution of 70 mu of tetrahydrofuran and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 20 pm and dried.

Example 1 Charging characteristics of the electrophotographic photoreceptor thus prepared
Measured using the same method. However, the charging polarity was set to 10. Show the results.

vo: +695V El/2: 1.2uux, sec Example 21 A charge transport layer and a charge generation layer similar to Example 1 were sequentially laminated on the nylon layer of the aluminum plate coated with the nylon layer used in Example 20. However, an electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the layer structure was reversed.

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

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

Vg: +690V, El/2: 1.8 Jlux, see.

[Effects of the Invention] In the electrophotographic photoreceptor of the present invention, it is presumed that by using a specific disazo pigment in the photosensitive layer, carrier generation efficiency and/or carrier transport efficiency within the photosensitive layer are improved. As a result, the electrophotographic photoreceptor is highly sensitive and durable, especially in potential stability during long-term use.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, characterized in that the photoconductive layer contains a disazo pigment represented by the following general formula (1). . General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) In the formula, A and A' represent coupler residues having a phenolic hydroxyl group.