JPH01271758A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve spectral sensitivity for particularly near infrared region and infrared region by incorporating a specified disazo pigment into a photosensitive layer on a base plate. CONSTITUTION:A disazo pigment expressed by the formula I is incorporated into a photosensitive layer on an electroconductive base plate. In the formula I, each A and A' is a coupler residue having phenolic OH group(s). A specific example for the coupler residue is that expressed by the formula II. In the formula II, Z is a residue necessary for forming a polycyclic or heterocyclic ring by condensing with a benzene ring; each R1 and R2 is an H atom or a (substituted) alkyl group, etc.; Y is an O atom or S atom; n is zero or 1. Thus, an electrophotographic sensitive body having stable potential characteristic against repetitive use, and wide spectral sensitivity ranging from visible region to near infrared and infrared region, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 the photoreceptor.

[Prior Art] Electrophotography, as disclosed in U.S. Pat. No. 2,297,691, involves coating an insulating material in the dark, the electrical resistance of which 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) The ability to quickly dissipate charges by light irradiation.

BACKGROUND ART Conventionally, as an electrophotographic photoreceptor, a photoreceptor having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, or cadmium sulfide as a main component has been used. However, although these satisfy the conditions (1) to (3) above, they have poor thermal stability and moisture resistance.

It is not necessarily satisfactory in terms of durability and the like.

For example, when selenium crystallizes, its properties as a photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as a photoreceptor deteriorates. In addition, cadmium sulfide has problems in moisture resistance and durability, and zinc oxide has problems in smoothness, hardness, and scratch resistance.

Furthermore, most inorganic photoreceptors have a limited photosensitive wavelength range. For example, selenium has a sensitive wavelength range in the blue range and has almost no sensitivity in the red range.

For this reason, various methods have been proposed to extend the photosensitivity to a longer wavelength range, 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, its sensitivity wavelength range is narrow and it is necessary to add various sensitizers.

In order to overcome the drawbacks of these G4M 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-dolinitrofluorenone-9-one, and a photoreceptor in which poly-N-vinylcarbazole is sensitized with a biryllium base dye. Things (Tokuko Showa 4)
8-25658).

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. , a charge generation layer), and a layer consisting mainly of a substance that accepts and transports the carrier generated by the charge generation layer (hereinafter referred to as a charge carrier) (hereinafter referred to as F, Tun 6 Oki) Compared to conventional electrophotographic photoreceptors, some photoreceptors have been put into practical use because they generally have higher sensitivity and can withstand repeated use. There are some.

For example, US Pat.
Photoreceptor with US 4. ′? The specification of Japanese Patent Application No. 3871882 describes M, Q, and E, which are made of derivatives of perylene pigments.
and a charge transport layer made of a condensate of 3-bromopyrene and formaldehyde. Further, as a photoreceptor using a bisazo pigment or a trisazo pigment as a charge generating substance, Japanese Patent Application Laid-Open No. 59-33445,
JP-A-56-46237, JP-A-60-1112
Publication No. 49, JP-A-58-4151, JP-A-60
JP-A-113246, JP-A-62-150257, etc. are already known. However, these bisazo pigments or trisazo pigments are not necessarily satisfactory in terms of sensitivity, residual potential, or stability during repeated use, and the selection range of ia cargo is also limited. It does not fully satisfy the wide range of demands of photographic processes.

Further, as a disazo pigment having an aromatic carbonyl compound in the central skeleton, JP-A-54-22834, JP-A-56-143437, 0K+y+ 57-138
No. 646 is already known.

However, the sensitivity for these disazo compounds is low.

The potential stability during durability is not necessarily satisfactory, and in particular, the sensitivity in the near-infrared and infrared regions is not sufficient.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel photoconductive material, an electrophotographic material containing a specific disazo pigment that is stable to heat and light and has excellent carrier generation ability. To provide a photoreceptor, to provide an electrophotographic photoreceptor that has practical high time sensitivity and stable potential characteristics during repeated use, and has a wide spectral sensitivity spanning from the visible region to the near-infrared and infrared regions. It's about doing.

[Means for Solving the Problems, Effects] The present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, in which the photosensitive layer contains a trisazo pigment represented by the following general formula (1). Consists of an electrophotographic photoreceptor.

In the formula, A and A'' represent coupler residues having a phenolic hydroxyl group, and may be the same or different.

More preferable specific examples of coupler residues having a phenolic hydroxyl group represented by A and A' include the following general formula (2
) to (6) are mentioned.

°・z' In the formula, Z is fused 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, dihenzonaphthofuran ring, or diphenylene sulfide ring. The fused ring of Z is 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 7 group containing the nitrogen atom to which R2 is bonded in the ring, and the alkyl group includes methyl, ethyl, propyl, butyl, etc., and the aryl group includes phenyl, diphenyl, naphthyl, anthryl, etc. Aralkyl groups include benzyl, phenethyl, naphthylmethyl, etc.; heterocyclic groups include carbazole, dibenzofuran,
penzimicunlon, benzthiazole, thiazole,
Examples include groups such as pyridine. Y represents an oxygen or sulfur atom, and n is an integer of O or l.

In the formula, R3 represents a hydrogen atom, an alkyl group which may have one substituent, an aryl group or an aralkyl group. R3
A specific example of is shown by the same example as R, , R2 above.

Examples of substituents that the alkyl group, aryl group, aralkyl group, alkoxy group, and heterocyclic group represented by substituents R1 to R3 in general formulas (2) and (3) include fluorine atom, chlorine atom, , halogen atoms such as iodine atom and bromine atom, alkyl groups such as methyl, ethyl, propyl, isopropyl and butyl, alkoxy groups such as methoxy, ethoxy, propoxy and phenoxy, nitro group, cyan group, dimethylamino, dibenzylamino, Examples include substituted amino groups such as cyphenylamino, morpholino, piperidino, and pyrrolidino.

1, Hl In the formula, M represents a divalent aromatic hydrocarbon group or a heterocyclic divalent group containing a nitrogen atom in the ring, and as a divalent aromatic hydrocarbon group. - Divalent groups of monocyclic aromatic hydrocarbons such as phenylene, 0-naphthylene, perinaphthylene, 1
, 2-antrylene, 9. Examples include divalent groups of condensed polycyclic aromatic hydrocarbons such as lO-phenanthrylene, and examples of divalent groups of heterocycles containing a nitrogen atom in the ring include 3,4-
pyridinediyl 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.

Z' 12 In the formula, R4 represents an aryl group or a heterocyclic group which may have a substituent, and specific examples include phenyl, naphthyl, anthryl, pyrenyl, pyridyl, thienyl, furyl, and carbacylyl groups.

Further, tδ substituents of aryl groups and heterocyclic groups include halogen atoms such as fluorine atom, hydrogen atom, iodine atom, and bromine atom, alkyl groups such as methyl, ethyl, propyl, inpropyl, and butyl, methoxy, and ethoxy , alkoxy groups such as propoxy, phenoxy, nitro groups, cyan groups, substituted amino groups such as dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolidino.

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

"z' In the formula, R5 and R6 represent a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group, an aryl group, or a heterocyclic group, and specifically, the 1±alkyl group is methyl,
Ethyl, propyl, butyl, aralkyl groups include benzyl, phenethyl, naphthylmethyl, aryl groups include phenyl, diphenyl, naphthyl, anthryl, heterocyclic groups include carbazolyl, thienyl, pyridyl, furyl, etc. Examples of 1δ 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, impropyl, and butyl; Examples include alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy, and substituted amino groups such as nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino, morpholino, piperidino, and pyrrolisif.

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

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

The method of description is that in the basic type, the changed parts A and A'
Let us show the following.

Basic Exemplary Pigment (1-1) Exemplary Pigment (1-2) Exemplary Pigment (1-3) Exemplary Pigment (1-4) Exemplary Pigment (1-5) Exemplary Pigment (1-6) Exemplary Pigment (1-7) ) Exemplary Pigment (1-8) Exemplary Pigment (1-9) Exemplary Pigment (1-10) Exemplary Pigment (1-11) Exemplary Pigment (1-12) Exemplary Pigment (1-13) Exemplary Pigment (1-14) Exemplary Pigment (1-15) Exemplary Pigment (1-16) Exemplary Pigment (1-17) Exemplary Pigment (1-18) Exemplary Pigment (1-19) Exemplary Pigment (1-20) Exemplary Pigment (1-21) Exemplary Pigment Pigment (1-22) Exemplary Pigment (1-23) Exemplary Pigment (1-24) Exemplary Pigment (1-25) Exemplary Pigment 1 (1-26) Exemplary Pigment (1-27) Exemplary Pigment (1-28) Exemplary Pigment (1-29) Exemplary Pigment (1-30) Exemplary Pigment (1-31) Exemplary Pigment (1-32) Exemplary Pigment (1-33) Exemplary Pigment (1-34) Exemplary Pigment (1-35) Exemplary Pigment Pigment (1-36) Exemplary pigment (1-37) Exemplary pigment (1-38) Exemplary pigment (1-39) Exemplary pigment (1-40) Exemplary pigment (1-41) Exemplary pigment (1-12) Exemplary pigment (1-43) Exemplary pigment (1-44) Exemplary pigment (1-46) Exemplary pigment (1-47) Exemplary face $4 (1-48) Exemplary pigment (1-49) Exemplary pigment (1-50) Exemplary pigment Pigment (1-51) Exemplified Pigment (1-52) Exemplified Pigment (1-53) Exemplified Pigment (1-54) Exemplified Pigment (1-55) Exemplified Pigment (1-56) Exemplified Pigment (1-57) Exemplified Pigment (1-58) CΩ Exemplary Pigment (1-59) Exemplary Pigment (1-60) Exemplary Pigment (1-61) Rigidity Exemplary Pigment (1-62) Exemplary Pigment (1-63) Exemplary Pigment (1-64) C Exemplified Pigment (1-65) Exemplified Pigment (1-66) Exemplified Pigment (1-67) Exemplified Pigment (1-68) Exemplified Pigment (1-69) B Exemplified Pigment (1-70) r Exemplified Pigment Pigment (1-71) B" Exemplary pigment (1-72) l: Ir Exemplary pigment (2-1) A・A": 9H3 Exemplary face N (2-2) A, A': 083 H Exemplary pigment (2 -3) Exemplary pigment (2-4) Exemplary pigment 1 (2-6) υH Exemplary pigment (3-1) Exemplary pigment (3-2) H Exemplary pigment (3-3) Exemplary pigment (3-4) Exemplary pigment Pigment (3-5) Exemplary pigment (4-1) Exemplary pigment (4-2) Exemplary face! -1 (4-3) Exemplary Pigment (4-4) Exemplary Pigment (4-5) (Exemplary Pigment (5-1) Exemplary Pigment (5-2) Exemplary Pigment (5-3) Exemplary Pigment (5-4) ) Exemplary pigment (5-5) Exemplary face + (5-6) CS! Exemplary pigment (6-1) Exemplary pigment (6-2) Exemplary face + (6-3) Exemplary pigment (6-4) (3! A general method for producing the disazo pigment represented by the general formula (1) used in the present invention will be explained.

A, A' in the general formula of the disazo pigment represented by the general formula (1)
are the same, the diamine represented by the following general formula (7) is converted into a tetrazonium salt by a conventional method using sodium nitrite or nitrosyl sulfuric acid, and the coupler components A and A' are prepared.
It can be synthesized by performing an aqueous coupling with the tetrazonium salt, or by extracting the obtained tetrazonium salt as a stable salt such as a fluoroborate salt and then performing coupling in an organic solvent such as dimethylformamide.

A, A' in the general formula of the disazo pigment represented by the general formula (1)
If the pigments are different, in the coupling reaction, first couple with the first coupler component to form a monoazo pigment, then couple with the second coupler component to form a disazo pigment, or mix the two coupler components. can be synthesized by performing a coupling reaction.

The film containing the disazo compound F+ represented by the above-mentioned general formula (1) exhibits photoconductivity, and therefore can be used as a photoconductive layer of an electrophotographic photoreceptor.

That is, in the present invention, an electrophotographic photoreceptor can be constructed by forming a film on a conductive substrate by dispersing the disazo pigment represented by the above-mentioned general formula (1) in a suitable binder.

In a preferred embodiment of the present invention, the photoconductive coating described above is 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. be able to.

The charge generation layer contains as much of the above-mentioned photoconductive disazo residue as possible in order to obtain sufficient absorbance, and also contains "7!" in order to shorten the range of the generated charge carriers.
J membrane layer, e.g. 5 pLm or less, preferably 0.01-1
It is preferable to form a thin film layer having a thickness of 10 m.

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 must be injected into the charge transport layer without being deactivated by recombination or trapping. This is due to the fact that

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

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. Preferably polyvinyl butyral, polyvinyl benzal, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin,
Examples include insulating resins such as 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 resin, and is preferably selected from those that do not dissolve the underlying charge transport layer or undercoat layer.

Specific organic solvents include alcohols such as methanol, ethanol, and isopropanol, 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 tetrahydrofuran, dioxane, ethylene glycol monomethyl ethyl, esters such as methyl acetate, ethyl acetate, chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene Aliphatic halokenated hydrocarbons such as benzene, toluene,
Aromatic compounds such as xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating is done by dipping coach ink method, spray coating method,
spinner coating method, bead coating method, Mayer-per coating method, blade coating method,
This can be carried out using a coating method such as a roller coating method or a curtain coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at a temperature of 30 to 200'C for 5 minutes to 2 hours, either stationary or under ventilation.

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 substrate, or may be located between the conductive substrate and the charge generation layer.

When the charge transport layer is formed on the side farther from the charge generation layer when viewed from the conductive substrate, the substance that transports charge carriers in the charge transport layer (hereinafter referred to as charge transport material) is a material that is capable of absorbing electromagnetic waves to which the charge generation layer is sensitive. Preferably, it is substantially insensitive to the wavelength range. The term "electromagnetic waves" as used herein includes a broad definition of light rays including gamma 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 matches or overlaps that of the charge generation layer, charge carriers generated in both layers trap 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, 2,4.7-dolinitro-9-fluorenone, 2
,4,5.7-tetranitro-9-fluorenone,2,
4.7-Dolinitro 9-dicyanomethylenefluorenone.

2.4,5.7-titranitroxanthone, 2°4.8
- There are 7L electron-attracting substances such as trinidrothioxanthone, and polymerized versions of these electron-attracting 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-Ethylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N
-Phenylhydrazino, p-pyrrolidinobenzaldehyde N, N-diphenylhydrazone, 1,3.3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, p-ethylhensaltehyde 3-
Hydrazones such as methylbenzthiazolinone-2-hydrazone, 2,5-his(p-diethylaminophenyl)-1,3,4-oxadiazole, l-phenyl-3
-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)hilazoline, 1-[quinolyl(2
)] -3-(p-diethylaminostyryl)-5-(
p-diethylaminophenyl)pyrazoline, l-[pyridyl(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyracillin,
1-[6-medoxypyridyl (2)] -3-(p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-[pyridyl(3)]-3-
(p-diethylaminostyryl)-5-(p-diethylaminophenyl)birazoline, 1-[lepicyl (2) no 3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyranline, 1-[pyridyl(
2)] -3-(p-diethylaminostyryl-4-methyl-5-(p-diethylaminophenyl)pyranrin, ■-[pyridyl (2)] -3-(α-methyl-p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyranrin, 1-phenyl-3-(p-diethylaminostyryl)=4-methyl-5-(p-diethylaminophenyl)pyranrin, 1-phenyl-3-(
α-benzyl-p-diethylaminostyryl)-5-(
Pyrazolines such as p-diethylaminophenyl) pyrazoline and spiropyranline, α-phenyl-4-N, N
-diphenylaminostilbene, N-ethyl-3-(α
-phenylstyryl)carbazole, 9-p-dibenzylaminobenzylidene-9H-2luorenone, 5-P-
Ditolylaminobenzylidene-5H-dibenzo[a,
d] Styryl compounds such as cycloheptene, 2-
(p-Sheftylaminostyryl)-6-dinithylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-
Oxazole compounds such as (p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2
-(p-diethylaminostyryl)-6-dinithylaminopentthiazole and other thiazole compounds, bis(
Triarylmethane compounds such as 4-diethylamino-2-methylphenyl)phenylmethane, l,1-his(4-N,N-diethylamino-2-methylphenyl)
Hebutane, polyarylalkanes such as 1,1,2.2tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-N-
Examples include vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylanthracene, pyrene-formaldehyde resin, and ethylcarbazole formaldehyde resin.

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

Moreover, these 7F cargo transport containers can be used alone or in combination of two or more.

When the charge transport material does not have good film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as interlayers include acrylic resins, polyarylates, polyesters, polycarbonates,
Polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone,
Examples include insulating resins such as polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

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 40 gm, but the preferred range is 15 to 30 gm.
It is 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 conductive substrate.

As the conductive substrate, the substrate itself is conductive, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc., can be used.
In addition, plastics (e.g. polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, ,
(polyfluorinated ethylene, etc.), substrates made of plastic coated with conductive particles (e.g. carbon black, silver particles, etc.) together with a suitable binder, substrates made of plastic or paper impregnated with conductive particles, plastics containing conductive polymers, etc. can be used.

A subbing layer can be provided between the conductive substrate and the photosensitive layer to provide a barrier function and an adhesive function. The subbing layer is casein, polyhinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, (nylon 6,
Nylon 66, nylon 61o, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, ceratin, aluminum oxide, etc.

The thickness of the subbing layer is 5 μm or less, preferably 0.1 to 3 μm.
m is appropriate.

When using a photoreceptor in which a conductive substrate, 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, and after charging, 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 the exposed area and the unexposed area. It will come to life.

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,
You can also develop it and wear it in the summer. 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, 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 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 substrate, a charge transport layer, and a charge generation layer are arranged in this order.When the charge transport material is an electron transport material, the surface of the charge generation layer must be negatively charged, and exposure after charging is required. Then, in the exposed portion, electrons generated in the charge generation layer 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 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 generation layer is made of a hole transporting substance, 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 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 hydrazones, pyrazolines, styryl compounds, oxanols, thianols, triarylmethanes, polyarylalkanes, triphenylamine, poly-N-vinylcarbazoles, etc. Organic photoconductive materials, zinc oxide, sulfidation power 1”
A photosensitive film can be prepared containing a disazo pigment represented by the above-mentioned general formula (1) as a sensitizer for an inorganic photoconductive substance such as mium or selenium.

This photosensitive coating is made of these photoconductive substances and the general formula (
A film is formed by coating the disazo pigment shown in 1) together with a binder.

Further, as the electrophotographic photoreceptor of the present invention, the general formula (
Examples include an electrophotographic photoreceptor in which the cis-ion pigment shown in 1) is contained in the same layer as a charge transporting substance.

In this case, in addition to the charge transporting substance described above, an IL load transfer complex compound consisting of poly N-hinylcarhazole and trinitrofluorenone can be used.

The IL photographic photoreceptor of this example has the general formula (1) described in 1iii.
It is produced by dispersing the disazo pigment shown in ) and the charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and then forming a coating.

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.

If necessary, two or more types of cis-an pigments represented by the general formula (1) may be used in combination to increase the sensitivity of the photoreceptor or to obtain a panchromatic photoreceptor. It is also possible to use them in combination or in combination with charge generating substances 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.

[Examples] Examples 1 to 20 A subbing layer made of a 0.1 p, m vinyl chloride-maleic anhydride-vinyl acetate copolymer resin was provided on an aluminum plate.

Next, 5 g of the above exemplary pigment (1-41) was added to a solution prepared by dissolving 2 g of butyral resin (degree of butyralization 63 mol%, number average molecular weight 20,000) in cyclohexanone (95 m f), and dispersed in a sand mill for 20 hours. did. This dispersion was applied to the previously formed subbing layer so that the film thickness after drying was 0.5 gm.
A charge generation layer was formed by coating with a Mayer bar and drying.

5g of hydrazone compound and polymethyl methacrylate (
Dissolve 5 g of number-average molecules [100,000] in 70 m of chlorobenzene, and apply this solution onto the charge generation layer so that the film thickness after drying is 20.
gm with a Mayer Parr and dried to form a charge transport layer, thus preparing the -H(i-child photoreceptor) of Example 1.

The exemplified pigment (1-41) used in Example 1 was replaced by the exemplified pigment f, and the other conditions were the same as in Example 1, and the electrophotographic photoreceptors corresponding to Examples 2 to 20 were completely Created in the same way.

The electrophotographic photoreceptor thus prepared was tested using an electrostatic copying paper tester (Kawaguchi Denki Model 5P-428).
) was corona charged at -5.5 KV using a Statinta method, held in a dark place for 1 second, and then exposed to light at an illuminance of 2 lux; Hi7 charging characteristics were investigated.

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

h l Example 6 Pigment V Q (-V E l/2
1ux+5ec1 (1-41) 700
1.72 (1-1) 650 4.
23 (1-8) 670 5
．． 74 (1-9) 670
4.55 (1-16) 665
11.26 (1-23) 695
3.27 (1-25) 680
7.88 (1-35) 695
9.89 (1-37) 675
1.910 (1-44) 7
00 3. 111 (1-52)
670 3.212 (1-54)
685 1.613 (1-6
0) 705 2.014 (1-
63) 695 1. 315 (
1-71) 695 1.516
(2-1) 665 5.217
(3-1) 655 7.11
8 (4-1) 695 4.
119 (5-1) 660 1
2.720, (6-1) 680
3.0 Comparative Examples 1 to 3 In place of the pigments used in Examples 9, 14, and 15,
A photoreceptor was prepared in the same manner as in Example 1 except for using the disazo pigments described in JP-A No. 4-22834, JP-A-57-138646, and JP-A-61-22346. The charging characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

(Comparative example 1: Corresponds to Example 9) Comparative pigment vow-695V, El/2: 4.0uux, 5ec (Comparative example 2: Corresponds to Example 14) Comparative pigment J5 vony 680V, El/2: 5. 0uux, 5ee (Comparative Example 3: Corresponds to Example 15) Comparative pigment vony 685V, El/2 near, 0uux, see Examples 21 to 24 Electrophotographic photosensitive material prepared in Example 1.12.14.15 Fluctuations in light potential and dark potential during repeated use were measured.

The measurement method was as follows: A photoreceptor was attached to an electrophotographic JiJ 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 compound machine has a 4111 configuration in which an image is obtained on the transfer paper as the sitter is driven.

Using this 't'f, "j machine, the initial bright area potential (V
L) and 1lfj f'jR't1 position (Vo) are set to tL-200V and -700V, respectively, and 5.0
The light potential (VL) and dark potential (VL) after 00 uses
D) was measured. Show the results.

23' 14 690 21
5 From this result, sensitivity and potential stability during long-term use are good.

Example 25 One of the charge generation layers formed in Example 1 was coated with 2,4.7-
Dolinitro 9-fluorenone 5g and poly-4,4°-
Dioxydiphenyl-2,2-propane carbonate (
After drying a coating solution prepared by dissolving 5g of molecular weight 300,000) in 70mM of tetrahydrofuran, the coating amount was 10g/m2.
It was applied and dried.

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

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

vo: +700V El/2: 3.7m uX, SeC Example 26 A polyvinyl alcohol film with a film thickness of 0.5 ALm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

Next, a dispersion of the disazo pigment of the exemplary pigment (1-47) used in Example 2 was applied onto the previously formed polyvinyl alcohol layer using a Mayer par so that the film thickness after drying would be 0.5 μm. 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 Zffi polycarbonate (viscosity average molecular weight 30,000) in 32.5 m 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.

The charging characteristics and durability characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Examples 1 and 21. Show the results.

Voney 700V, El/2: 1.7uux, see Durability characteristics Initial VD Knee 700 VL, Knee 200 After 5,000 sheets durability Vo Knee 670 VL Knee 215 Example 27 On an aluminum plate with a thickness of loogm, soluble nylon ( 6-
A methanol solution of 66-610-12 quaternary nylon copolymer) was applied and dried to form a subbing layer with a thickness of 0.5 gm.

Next, 5 g of 2,4.7-dolinitro-9-fluorenone
A charge transfer complex was prepared by dissolving 5 g of poly-N-vinylcarbazole (number average molecular weight: 300,000) in 70 ml of tetrahydrofuran. This charge transfer complex and the exemplary pigment (1-
41), 5 g of polymethyl methacrylate-styrene copolymer resin (molecular weight 250,000), and 7 g of tetrahydrofuran.
It was added to the solution dissolved in 0ml and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 20 pLm and dried.

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

vo: +695V El/2: 4.2 sentences ux, sec Example 28 The same charge transport layer and charge generation layer as in Example 1 were placed on the nylon layer of the aluminum substrate with the nylon layer used in Example 27. An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the layers were sequentially laminated and 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.

vo +690V, El/2: 2.7Jljux, sec.

[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 substrate, characterized in that the photosensitive layer contains a disazo pigment represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) In the formula, A and A' represent coupler residues having a phenolic hydroxyl group, and may be the same or different. 2. The electrophotographic photoreceptor according to claim 1, wherein one or both of A and A' in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (2). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (2) In the formula, Z is a residue necessary to form a polycyclic aromatic ring or a heterocycle by condensing with a benzene ring, and R_1 and R_
2 is a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, a heterocyclic group, or R_1, R_2
Indicates a cyclic amino group containing a bonded nitrogen atom in the ring,
Y represents an oxygen atom or a sulfur atom, and n is an integer of 0 or 1. 3. The electrophotographic photoreceptor according to claim 1, wherein one or both of A and A' in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (3). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (3) In the formula, R_3 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 one or both of A and A' in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (4). ▲There are numerical formulas, chemical formulas, tables, etc.▼ (4) In the formula, M represents a divalent aromatic hydrocarbon group or a heterocyclic divalent group containing a nitrogen atom in the ring. 5. The electrophotographic photoreceptor according to claim 1, wherein one or both of A and A' in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (5). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (5) In the formula, R_4 represents an aryl group or a heterocyclic group that may have a substituent, and Z has the same meaning as Z in the general formula (2) above. . 6. The electrophotographic photoreceptor according to claim 1, wherein one or both of A and A' in the general formula (1) is a coupler residue having a phenolic hydroxyl group represented by the following general formula (6). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (6) In the formula, R_5 and R_6 represent a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group, an aryl group, or a heterocyclic group, and Z represents the general It has the same meaning as Z in formula (2).