JPS6219874A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a high sensitivity characteristic and stable potential characterist in repeated uses by incorporating a specific pentakisazo pigment into a photosensitive layer. CONSTITUTION:The pentakisazo pigment expressed by the formula I [Ar1-Ar6 are respectively an (un)substd. arylen, bivalent condensation polycyclic arom. group or an org. group contg. a bivalent heterocyclic group; A is a residual coupler group having phenolic OH] is incorporated into the photosensitive layer provided on a conductive substrate. A in the formula I is preferably the formulas II-IV [X is a residual group which forms a polycyclic arom. ring or heterocycle by condensing with a benzene ring; R1, R2 are H, (un)substd. alkyl, aralkyl, aryl or heterocycle or residual groups which together form a cyclic amino group with an N atom; R3 is an (un)substd. alkyl, aralkyl, aryl; Y is an arom. hydrocarbon bivalent group or a residual group which forms a vibalent heterocycle with an N atom]. This pentakisazo pigment may be used in the charge generating layer of a function sepn. type photosensitive body. The spectral sensitivity is widened up to a long wavelength region and the potential stability during the durable use is improved by using such pigment.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor using a new electrophotographic photosensitive material. This invention relates to an electrophotographic photoreceptor contained in a layer.

[Conventional technology]

Conventionally, pigments and dyes exhibiting photoconductivity have been published in numerous publications.

For example, “RCA Review’ VoL 23
7 in r P, 413-P, 419 (1962, 9)
There have been publications on the photoconductivity of talocyanine pigments, and electrophotographic photoreceptors using these 7 talocyanine pigments have been published in U.S. Pat. No. 3,397,086 and U.S. Pat.
1611: Publication, etc. In addition, examples of organic semiconductors used in electrophotographic photoreceptors include those disclosed in US Pat. No. 4,315,983, US Pat. No. 4,327,169, and 'Re5each Disclosure"2'
0517 (1981, 5)
Methine squaric acid dye shown in U.S. Pat. No. 3,824,099, U.S. Pat. No. 389
Examples include disazo pigments disclosed in US Pat. No. 8,084, US Pat. No. 4,251,613, and the like.

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

[Problem that the invention seeks to solve]

It is an object of the present invention to provide a new photoconductive material.

Another object of the present invention is to provide an electrophotographic photoreceptor that can be used in all existing electrophotographic processes and has practical high sensitivity characteristics and stable potential characteristics during repeated use.

[Means for solving problems]

In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate according to the present invention, the photosensitive layer has the following general formula (where Ar, +
Ar2+ Ar, *Ar4* Ar5 and Ar
6 represents an organic group containing an arylene group, a divalent condensed polycyclic aromatic group, or a divalent heterocyclic group, each of which may have a substituent, and A represents a coupler residue having a phenolic oH group) An electrophotographic photoreceptor containing a pentakisazo pigment represented by the following is provided.

In the formula, Ar l Ar l Ar l Ar
l Ars I Ar6 is an arylene group such as phenylene, naphthylene, hephenylene, anthrylene, a divalent condensed polycyclic aromatic ring group such as indene, acenaphthene, fluorene, diarylene, fluorenone, anthrone, anthraquinone, benzanthrone, or pyridine, quinoline,
Complexes such as benzoxazole, benzothiazole, pensoimitasole, penztriazole, 7enylpenzoxazole, quenylbensothiazole, phenylpensoimitasole, dibenzofuran, carbazole, xanthine, axozine, phenothiazine, diphenyloxadiazole, etc. Indicates a divalent organic group containing a ring. These arylene groups, divalent condensed polycyclic aromatic ring groups, and divalent heterocycle-containing organic groups include alkyl groups such as methyl, ethyl, gloyl, butyl, alkoxy groups such as methoxy, ethoxy, and propoxy, benzyl, 7 such as phenethyl, naphthylmethyl, etc.
Even if it has a ralkyl group, an aryl group such as phenyl, diphenyl, or naphthyl, a halogen atom such as chlorine, bromine, or iodine, an acyl group such as acetyl or benzoyl, a nitro group, a trifluoromethyl group, or a cyan group as a substituent. I do not care.

Further, as the Kaglar residue having a phenolic OH group of A in general formula (1), for example, the following general formula (
2) to (8) 20H R3 and R4 each represent an alkyl, aralkyl, aryl, or a heterocyclic group which may have a substituent; Aralkyl and aryl; Y represents a divalent aromatic hydrocarbon group or a residue that forms a heterocyclic divalent group together with the nitrogen atom; R
5 and R6 represent a hydrogen atom, an alkyl, aralkyl, aryl, or heterocyclic group even if it has a substituent, or a residue that together forms a 5- to 6-membered ring; R
7 and R8 each represent a hydrogen atom, an optionally substituted alkyl, aralkyl, aryl, or a heterocyclic group).

Examples of the polycyclic aromatic ring and heterocyclic ring-forming residues of X include naphthalene, anthracene, carbazole, benzcarbazole, dibenzofuran, benzonaphthofuran, and diphenylene sulfide.

In the case of R, + R2, alkyl is, for example, methyl, ethyl, propyl, butyl, etc., aralkyl is, for example, benzyl, phenethyl, naphthylmethyl, etc., and aryl is, for example, phenyl, diphenyl, naphthyl,
Such as Anthril. In particular, compounds in which R1 is hydrogen and R2 is a phenyl group having an electron-withdrawing group such as halogen, nitro, cyanide, or trifluoromethyl and an alkyl group such as methyl, ethyl, or butyl at the 〇-position are used. preferable.

Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine.

Specific examples of R3 and R4 are the same as those exemplified above for R1 and R2.

In addition, the alkyl group, aralkyl group, aryl group, and heterocyclic group of R1, R21R3, and R4 described above may further include other substituents,
For example, it may be substituted with the above-mentioned alkyl group, alkoxy group, halogen atom, nitro group, cyano group, or a substituted amine group such as trimethylamino, noethylamino, dibenzylamino, diphenylamino, morpholino, pinyrylene, and pyrrolidino.

In the definition, Y is a divalent aromatic hydrocarbon group such as a monocyclic aromatic hydrocarbon group such as O-phinidine, 0-
7-tyrene, perinaphthylene, 1,2-antrylene,
Examples include fused polycyclic aromatic hydrocarbon groups such as 9.10-phenanthrylene.

Examples of divalent heterocycles that form divalent heterocycles together with nitrogen atoms include 3.4-pyrazolediyl group, 2.2-pyridinediyl group, 4.5-pyrimidinecyh group, 617-
Examples include 5- to 6-membered heterocyclic divalent groups such as indazolediyl group, 5.6-benzimidazolediyl group, and 6.7-chiralindiyl group.

Examples of the aryl group, aralkyl group or heterocyclic group of R5r R6 include phenyl, naphthyl, anthryl, pyrenyl, aralkyl such as benzyl, phenethyl, naphthylmethyl, and heterocyclic groups such as pyridyl, chenyl, furyl, carbazolyl, etc. Ru. These may be substituted with the substituents described above. Furthermore, R5 and R6 represent residues that together form a 5- to 6-membered ring. This 5- to 6-membered ring may have a fused aromatic ring.

Examples of such groups include cyclopentylidene, cyclohexylidene, 9-fluorenylidene, 9-xanthenylidene, and the like.

Alkyl, aryl, araf in R and R8 Specific examples of ruki include the same ones as mentioned above.

Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine. These may be substituted with the substituents described above.

The specific example of X in formulas (7) and (8) is the same as that of X in formula (2) above. In particular, the ring to which X is bonded is preferably an anthracene ring, a benzcarbazole ring, or a carbazole ring. In particular, the benzcarbazole ring has a great effect of expanding the spectral sensitivity range to a long wavelength range, and is suitable for producing a photoreceptor having high sensitivity in the semiconductor laser range.

In the photoreceptor according to the present invention, a pentakisazo pigment characterized by a structure in which four azokaglar components are bonded symmetrically around an azo group having divalent organic groups on both sides and via N is used as a photoconductive material. It is used as a substance, and as can be easily inferred from its structure, the π-electron conjugated system is long and smooth, and either or both of carrier generation efficiency and carrier transport efficiency are significantly improved. Therefore, the photoreceptor of the present invention has high sensitivity,
The spectral sensitivity range extends to long wavelengths, and the potential stability during long-term use is also good. Therefore, it can be applied to high-speed copying machines, laser beam printers, LED printers, liquid crystal printers, etc. Furthermore, since a stable potential is ensured regardless of the previous history of the photoreceptor, stable images can be obtained.

Representative examples of the Nantakisazo pigment used in the present invention are listed below.

These 4-antakisazo pigments can be used alone or in combination of two or more. Further, these pigments can be used, for example, (Ar in the formula, l Ar2 t Ars l Ar4
p Ar51 Ar4 represents the same meaning as the symbol in general formula (1)) is octazotized by a conventional method, and then the corresponding coupler is aqueous coupled in the presence of an alkali, or the above diamine is Once the tetrazonium salt is isolated in the form of a fluorinated salt or a zinc chloride double salt, it is coupled with a coupler in the presence of an alkali in a suitable solvent such as N,N-dimethylformamide or dimethyl sulfoxide. The answer is whether it is easy to manufacture.

Next, a typical synthesis example of the pentakisazo pigment used in the present invention is shown below.

Synthesis Example 1 (synthesis of the above-exemplified intakisazo pigment A I): 80 Fnl of water and 33.2 m of concentrated hydrochloric acid in a 500 ml beaker.
A! (0.38 mol) and while cooling in an ice water bath,
Amine with the following structure (amine is French patent 139824)
16.72 g (0,02
9 mol) was added thereto and stirred while cooling in an ice water bath to bring the temperature of the solution to 3°C.

Next, sodium nitrite 8.2. A solution prepared by dissolving li' (0,122 mol) in 71 nlVc of water was added dropwise over 10 minutes while controlling the temperature within the range of 3 to 10°C, and after completion of the dropwise addition, the mixture was stirred for an additional 30 minutes at the same temperature. Carbon was added to the reaction solution and filtered to obtain an octazotized solution.

Next, put 700 g of dimethylformamide in a 2t beaker and add triethylamine s3.6. p(o,ss moles)t
-addition, t, 3-hydroxy-2-naphthoic acid anilide 3
2.12 g (0.122 mol) was added and dissolved.

This coupler solution was cooled to 6° C., and while controlling the liquid temperature at 6 to 10° C., the above-mentioned octazotized solution was added dropwise over 30 minutes with stirring, and then stirred at room temperature for 2 hours and further left overnight. The reaction solution was filtered, washed with water, and filtered to obtain a crude pigment having a concentration of 40.7.9 in water in terms of solid content.

Next, stirring filtration was repeated four times at room temperature using 400 ml of N,N-dimethylformamide. Thereafter, the mixture was stirred and filtered twice using 400 g of methyl ethyl ketone, and then dried under reduced pressure at room temperature to obtain purified pigments 38, 83, and F.

The yield was 80.0 cm. Melting point〉250゜Elemental analysis Calculated value (H) Experimental value (H) C74,
6374,49 H4344,4O N 13.39 13.
Although the synthesis method for more than 50 typical pigments has been described, other pentakisazo pigments represented by the general formula (1) can be synthesized in the same manner.

The coating containing the pentakisazo pigment described above exhibits photoconductivity and can therefore be used in the photosensitive layer of the electrophotographic photoreceptor described below. That is, in an embodiment of the present invention, the coating containing the pentakisazo pigment described above is coated on a conductive support. A shimiko photographic photoreceptor can be prepared by forming a film by vacuum evaporation, or by dispersing and containing it 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 compound as possible in order to obtain sufficient absorbance, and a washing thin film layer, for example, 5μ or less, to shorten the range of the generated charge carriers. , preferably a thin film layer having a thickness of 0.01 to 1 μm. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are transported by recombination or trapping without being deactivated. This is due to the need for layer pressure injection.

The charge generation layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on the substrate, or can be obtained by forming a film deposited in a vacuum deposition apparatus. 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, polyarylate (condensation polymer of bisphenol A and 7-talic acid, etc.), polycar? nate, polyester, phenoxy resin, 4? Insulating resins such as vinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylbilinone, cellulose resin, phletane resin, epoxy resin, casein, broken vinyl alcohol, and polyvinylbilinone can be mentioned. The amount of resin contained in the charge generation layer is 80% by weight or less, preferably 4% by weight.
0% by weight or less is suitable.

Solvents that dissolve these resins vary depending on the type of resin), and are preferably selected from those that do not dissolve the charge transport layer or undercoat layer described below.Specific organic solvents include methanol, ethanol, Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide,
Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic norodanes such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene. Hydrocarbons or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as the Meyer-G coating method, the grade coach ink method, the roller coach ink method, or the Curtin coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30℃ to 200℃ for 5 minutes or more
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, the charge transport layer may be laminated on top of the charge generation layer, or may be laminated below the charge generation layer.

When the charge transport layer is formed on the charge generation layer, the material that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport material) is within the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. Preferably, it is substantially insensitive. The term "electromagnetic waves" used herein includes a broad definition of "light rays" that includes 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 coincides with 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, furoanil, tetracyanoethylene, tetracyanoquinodimeth7,2,4.7-trinitro-9- Fluorenone, 2.4.5.7-tetranitro-9-fluorenone,
2,4.7-trinitro-9-dicyanomethylenefluorenone, 2.4,5.7-titranitroxanthone,
Examples include electron-withdrawing substances such as 2,4,8-trinidrothioxanthone, and polymerization of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N-ethyl force, n,
Hasol, N-(sopropyl-rubazole, N-methyl-N-phenylhydrazole-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazono-3-methylidene-9-ethylcarbazole, N,N- Diphenylhydrazino-3-methylidene-10-ditylphenothiazine, N,N-diphenylhydrazino-3-methylidene-10-ditylphenoxazine, P-soethylaminohenzaldehyde N, N-diphenylhydrazino, P -diethylaminobenzaldehyde-N-α-naphthyl-N-7enylhydrazone, P-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, i*3
+3-)! Hydrazones such as J methylindolenine-〇-aldehyde-N,N-diphenylhydrazino, P-noethylpenzaldehyde 3-methylbenzthiazolinone-2-hydrazone, 2.5-H'- diethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl-3-(p-diethylaminostyryl)
-5-(P-diethylaminophenyl)pyrazoline,
1-[quinolyl(2)]-3-(P-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2))-3-(P-diethylaminostyryl)-5-(P -diethylaminophenyl)pyrazoline, 1-[6-medogycybilidyl(2
)] -3-(P-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3))-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[Revisol(2):]-3-(P -diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(pyridyl(2) ml-3-(P
-diethylaminosteryl-4-methyl-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2
]-3-(α-methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-7enyl-3-(p-diethylaminostyryl)
Pyrazolines such as -4-methyl-5-(P-diethylaminophenyl) hilazoline, 1-phenyl-3-(α-benzo-P-noedylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, spiropyrazoline, 2 -(P-diethylaminostyryl)-6-dinithylaminopenzoxazole, 2-(P-diethylaminophenyl)-4-(P-tumethylaminophenyl)
-Oxazole compounds such as 5-(2-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)
-thiazole compounds such as 6-soethylaminopenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamine) -2-
Methylphenyl) hebutane.

1.1.2. Polyarylalkanes such as 2-tetrakis(4-N,N-trimethylamino-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine , poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, ethyl carnosol formaldehyde resin and the like.

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, polycarbanate, polystyrene, acrylonitrile-styrene copolymer,
Insulating resins such as acrylonitrile-tutadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. can be mentioned.

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 30μ, but the preferred range is 8 to 20μ.
It is. 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 substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and plastics (for example, polyethylene , polynolopyrene, polyvinyl chloride, polyethylene terephthalate, acrylic resin,
polyfluoroethylene, etc.), conductive particles (e.g., aluminum powder, tin oxide, zinc oxide, titanium oxide, carpin black, silver particles, etc.) with a suitable binder on plastic, glue, or the conductive substrate. A coated substrate, a substrate in which plastic or paper is impregnated with conductive particles, a plastic having a conductive polymer, etc. can be used.

It is also possible to provide a subbing layer having a layer function and an adhesive function between the conductive layer and the photosensitive layer. Subbing layer, casein, vinyl alcohol, nitrocellulose, ethylene-acrylic acid? Rimmer, polyamide (nylon 6,
Nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), teriurethane, gelatin, aluminum oxide, etc.

The thickness of the subbing layer is 0.1 to 5μ, preferably 0.5 to 3μ.
μ is appropriate.

When using a photoreceptor laminated with a conductive layer, a charge generation layer, and a charge transport layer, if 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 in the exposed area are injected into the charge transport layer, which then reaches the surface and neutralizes the positive charge, causing a decrease in the surface potential and creating an electrostatic charge between the exposed area and the unexposed area. Contrast occurs. A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

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

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

When using a photoreceptor in which a conductive layer, a charge transport layer, and a charge generation layer are laminated in this order, if the charge transport material is an electron transport material, the surface of the charge generation layer must be negatively charged. When exposed to light, electrons generated in the charge generation layer in the exposed area are injected into the charge transport layer and then reach the substrate. On the other hand, holes generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a positively charged toner.

This can be directly fixed, or the toner image can be transferred to paper, plastic, film, etc. and then developed and fixed. Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge 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 are injected into the charge transport layer in the exposed area. and then reaches the base. On the other hand, electrons generated in the charge generation layer reach the surface and the surface potential is attenuated, creating an electrostatic contrast with the unexposed area. During development, it is necessary to use a negatively charged toner, contrary to the case where an electron transporting substance is used.

Further, in another specific example of the present invention, the above-mentioned hydrazones,
Organic photoconductive substances such as pyrazolines, oxazoles, thiazoles, triarylmethanes, polyaryl alkanes, triphenylamine, poly-N-vinylcarbazoles, and inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. A photosensitive film can be obtained containing the above-mentioned pentakisazo pigment as a sensitizer. This photosensitive film is formed by coating these photoconductive substances and the aforementioned pentakisazo pigment together with a binder.

Another specific example of the present invention is an electrophotographic photoreceptor containing the aforementioned pentakisazo pigment and a charge transport material in the same layer. At this time, in addition to the above-mentioned charge transport material, poly-N-vinylcarbasol! =iJ Nitrofluorenone or ranal charge transfer complex compounds can be used. The electrophotographic photoreceptor of this example can be prepared by dispersing the aforementioned pentakisazo pigment and charge transfer complex compound in a polyester solution in tetrahydrofuran, and then forming a film thereon.

The pigment used in any of the photoconductors contains at least one type of pigment selected from pentakisazo pigments represented by the general formula (1), and its crystal form may be amorphous or crystalline. If necessary, two or more types of pentakisazo pigments represented by the general formula (1) may be used in combination for the purpose of increasing the sensitivity of the photoreceptor or obtaining a panchromatic photoreceptor by using a combination of pigments with different light absorptions. 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 radar printers, CRT printers, L
It can also be widely used in electrophotographic applications such as EDf printers, liquid crystal printers, and day plate making.

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

Examples 1 to 60 Aqueous ammonia solution of casein Q (casein 1
Apply 1 y of 1.2% ammonia water and 222 ml of water using Mayer Parr so that the film thickness after drying is 1.0 μm, and dry thoroughly.

Next, the exemplified pentakisazo pigment A 1.5 Ji"
The mixture was added to a solution prepared by dissolving butyral resin (butyralization degree: 63 mol %) 2II in 9.5 ml of ethanol and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed casein layer using a Mayer parser so that the film thickness after drying was 0.5 μm, and dried to form a charge generation layer. Next, hydrazone compound 5I of the structural formula and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were dissolved in 70rrLllC of benzene, and this was applied onto the charge generation layer using a Mayer perforator so that the film thickness after drying would be 12μ, and dried. A charge transport layer was formed thereon to produce a photoreceptor of Example 1. Boiled pentakisazo pigment 1. Corresponding photoreceptors of Examples 2 to 60 were prepared in exactly the same manner using other exemplary pigments shown in Table 1 instead.

The electrophotographic photoreceptor thus prepared was statically charged with corona at -5 kV using an electrostatic copying paper tester Model 5P-428 manufactured by Kawaguchi Electric (Koshi), held in a dark place for 1 second, and then exposed at an illuminance of 2 Lux. The charging characteristics were investigated.

As for the charging characteristics, the surface potential (vo) and the amount of exposure (E'A) required to attenuate the potential to A after 1 second of dark decay were measured, and the results are shown in Table 1.

Examples 61 to 65 The photoreceptors used in Examples 1, 8, 29, 40, and 83 were repeatedly used, and the fluctuations in bright area potential and dark area potential were measured. The measurement method is as follows.

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 has a configuration in which the cylinder is moved half way down and an image is obtained on transfer paper. Using this copying machine, the initial bright area potential (VL) and dark area potential (Vo) e are each set to -100 V. The bright area potential (VL) and the dark area potential (Vo) were measured after being set around -600V and used 5000 times.

The results are shown in Table 3.

From the data of Examples 1 to 65, the photoreceptors of the present invention had extremely good electrophotographic sensitivity and very good vDlvL stability even during repeated use.

Example 66 On the charge generation layer prepared in Example 1, 2,4.7-dolinitro-9-fluorenone 5.9,! = J IJ
-4,4-Dioxydiphenyl-2,2'-propane cargenate (molecular weight 300.000) A coating solution prepared by dissolving 5F in 70 ml of tetrahydrofuran had a coating amount of 101//m2 after drying. Apply it as desired and let it dry.

The electrostatic charge of the electrophotographic photoreceptor thus prepared was measured in the same manner as in Example 1. At this time, the charging polarity was set to ■. The results are shown in Table 4.

Table 4 V: +55 (1' FAI, : 4.3 tux-sec Example 67 A polyvinyl alcohol film having a thickness of 0.5 μm was formed on the aluminum surface of an aluminum-deposited polyethylene terephthalate film.

Next, the dispersion of the pentakisazo pigment used in Example 1 was applied onto the previously formed polyvinyl alcohol layer using a Mayer coater so that the film thickness after drying was 0.5μ, and dried to form a charge generating layer. was formed.

Next, pyrazoline compound 5y of the structural formula and polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid)
A solution prepared by dissolving 5 g of the above solution in 70 ml of tetrahydrofuran was coated onto the charge generation layer so that the film thickness after drying was 10 μm, 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.

The results are shown in Table 5.

Table 5 Vo: -585V E1%, : 3.2
Lux-sec initial stage After 5000 cycles Vo VL VD VL-6
00v-100V -625V -130"
/ According to the results in Table 5, the present invention has good sensitivity and good potential stability during long-term use.

Example 68 An ammonia aqueous solution of casein was coated on an aluminum plate with a thickness of 100 microns and dried to form a subbing layer with a thickness of 5 microns.

Next, 2.4.7-) dinitro-9-fluorenone 5
I and PoI) -N-vinylcarbazole (number average molecular weight 300.000>5 g) was dissolved in 70 M of tetrahydrofuran to form a charge transfer complex compound. This charge transfer complex compound and the above-mentioned exemplified pentakisazo pigment A74.11 were A solution prepared by dissolving 5 g of a polyester resin (Vylon: Toyobo) in 70 TL of tetrahydrofuran was added and dispersed. This dispersion was applied onto the undercoat layer to a dry film thickness of 12 microns and dried.

The charging characteristics and durability characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1. The results are shown in Table 6. However, the charging polarity was set to ■.

Table 6 vo:■560 V F, V2: 4.2tux-
aec Example 69 Example 1 except that the charge transport layer and charge generation layer of Example 1 were sequentially laminated on the casein layer of the casein layer-formed aluminum substrate used in Example 1, and the layer structure order was different. A photoreceptor was prepared in exactly the same manner as in Example 1, and the charge was measured in the same manner as in Example 1. However, the charging polarity was set to ■. Charging characteristics are shown in Table 7.

Table 7 vo ■560v FAI2 4. I Lux+sec Example 70 Casein ammonia water on aluminum cylinder?
l (casein 11.2, 9.28% ammonia water Ig,
22.2 mJ of water) coated by tl-dip coating method,
It was dried to form a subbing layer with a coating weight of 1-OJ/m2.

Next, 1 part by weight of the aforementioned pentakisazo pigment A46, 1 part by weight of Zotyral resin (S-LEC BM-2, manufactured by Sekisui Chemical Co., Ltd.), and 30 parts by weight of Improvil alcohol were dispersed for 4 hours using a Zormill disperser.

This dispersion was applied onto the previously formed subbing layer by dip coating and dried to form a charge generating layer. The film thickness at this time was 0.3 μO/.

Next, 1 part by weight of the hydrazone compound used in Example 1, polysulfone resin (P1700: Union Carbide Co., Ltd.)
), 1N-1i[IB=6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer. This coating was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time was 12 microns.

A corona discharge of 15 kV was applied to the photoreceptor thus prepared. The surface potential at this time was measured (initial potential V).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (dark decay Vk). Sensitivity was evaluated by measuring the exposure t (2 of E112 microziels/2) required to attenuate the potential vk to A after dark decay. At this time, a gallium/aluminum/arsenic ternary semiconductor radar (output power: 5 mW, oscillation wavelength: 7
78 nrn).

These results were as follows.

Vo: -520 is a laser beam printer (Canon type L
BP-CX') was set in place of the photoreceptor of LBP-CX, and an actual image forming test was conducted. The conditions are as follows: βru〇 surface potential knee roov after primary charging, surface potential knee 'isov after image exposure (g light! 2 μJ/cnt2), transfer potential: +7oov, developer polarity; 0 ceph speed: 50 trrrx/see, development conditions (development bias) knee 450V, development exposure scan method: image scan, - exposure before next charging: red full exposure of jOtuχ3ec.

Claims (5)

[Claims] (1) In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the photosensitive layer has the following general formula (1) ▲ mathematical formula, chemical formula,
There are tables, etc.▼(1) (In the formula, Ar_1, Ar_2, Ar_3, Ar_4, Ar
_5 and Ar_6 each represent an organic group containing an arylene group, a divalent condensed polycyclic aromatic group, or a divalent heterocyclic group which may have a substituent, and A is a coupler residue having a phenolic OH group. An electrophotographic photoreceptor comprising a pentakisazo pigment represented by: (2) A in the above general formula (1) is the following general formula (2)
Electrophotographic photoreceptor according to claim 1, which is represented by (8): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(3) ▲Mathematical formulas, chemical formulas , tables, etc. ▼ (4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (6) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (7) ▲ Mathematical formulas , chemical formulas, tables, etc.▼(8) (In the formula, , represents an aralkyl, aryl, or a heterocyclic group, or a residue that together with a nitrogen atom forms a cyclic amino group; R_3 and R_4 each represent an alkyl, aralkyl, or aryl that may have a substituent; Y is Indicates a divalent group of an aromatic hydrocarbon or a residue that forms a divalent heterocyclic group together with a nitrogen atom; R_5 and R_6 are hydrogen atoms, alkyl or aralkyl which may have a substituent. , represents an aryl or heterocyclic group, or represents a residue that together forms a 5- to 6-membered ring; R_7 and R_8 each represent a hydrogen atom, an alkyl, aralkyl, aryl, or a heterocyclic group which may have a substituent. (represents a ring group). (3) The electronic according to claim 1, wherein the photosensitive layer is of a functionally separated type consisting of a charge generation layer and a charge transport layer, and the charge generation layer contains a pentakisazo pigment represented by the above general formula (1). Photographic photoreceptor. (4) R_1 in the above general formula (2) is hydrogen,
Claims No. 1 in which R_2 is a substituted phenyl represented by the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (wherein R_9 is a substituent selected from halogen, nitro, cyano, trifluoromethyl, and acyl) 2. Electrophotographic photoreceptor. (5) In the above general formula (2), R_1 is hydrogen,
Claim 2, wherein R_2 is a phenyl group which may have a substituent, and X together with the benzene ring forms the following group ▲Mathical formula, chemical formula, table, etc.▼ Electrophotographic photoreceptor.