JPH0579984B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an electrophotographic photoreceptor, and more specifically,
The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a specific azo pigment. Conventional technology In the past, inorganic photoconductive substances such as amorphous selenium, selenium alloys, cadmium sulfide, and zinc oxide, and organic photoconductive substances such as polyvinyl carbazole and its derivatives have been used as electrophotographic photosensitive materials. is widely known. Organic photoconductive materials have advantages over inorganic materials in terms of transparency, film-forming properties, flexibility, manufacturability, and the like. Furthermore, in recent years, electrophotographic photoreceptors containing various azo pigments in the photosensitive layer have been proposed. (for example,
JP-A No. 56-143437, No. 59-31961, No. 59-
(See No. 218452 and No. 60-189759) Problems to be Solved by the Invention The reason why organic photoconductive materials have not been used in electrophotographic photoreceptors despite having many advantages as described above is that This is because they are inferior to inorganic types in terms of sensitivity and durability. Various azo pigments have been proposed in the past for the purpose of improving these drawbacks, but these have not yet been fully satisfactory. Therefore, it is an object of the present invention to improve the above-mentioned drawbacks when using an organic photoconductive substance, and its purpose is to provide a highly sensitive and highly durable electrophotographic photosensitive material. It's about offering your body. Means for Solving the Problems As a result of further study on azo pigments having the structural formula as proposed in the past, the present inventors found that
Among the diazo components or coupling components constituting the azo pigment described in the above publication, the compound represented by the following general formula () as the diazo component, and the compound represented by the following general formula () as the coupling component. The present inventors have discovered that bisazo compounds synthesized by selecting and coupling these compounds can be advantageously used in electrophotographic photoreceptors, and have completed the present invention.

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[Formula] (In the formula, A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring.) Therefore, the electrophotographic photoreceptor of the present invention has a conductive It is characterized in that the photosensitive layer on the support contains a bisazo compound represented by the following general formula ().

embedded image (In the formula, A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring.) The present invention will be explained in detail below. To further explain the bisazo compound represented by the general formula () used in the electrophotographic photoreceptor of the present invention, in the general formula (), A
represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring. As the divalent aromatic hydrocarbon group, for example, o
- Divalent monocyclic aromatic hydrocarbon group such as phenyl group, o-naphthylene group, perinaphthylene group,
Examples include divalent condensed polycyclic aromatic hydrocarbon groups such as 1,2-anthraquinonyl group and 9,10-phenanthrylene group. In addition, examples of the divalent heterocyclic group containing a nitrogen atom in the ring include 3,4-pyrazolediyl group, 2,3-
Pyridinediyl group, 3,4-pyridinediyl group,
Examples include divalent heterocyclic groups such as 4,5-pyridinediyl group, 5,6-benzimidazolediyl group, and 6,7-quinolinediyl group. In the present invention, these divalent aromatic hydrocarbon groups and divalent heterocyclic groups containing a nitrogen atom in the ring may have a substituent. As a substituent, C ₁ -
C ₁₈ alkyl group, C ₁ - C ₄ alkoxy group, C ₁ -
_C4 alkoxycarbonyl group, carboxyl group,
Hydroxyl group, nitro group, cyano group, halogen atom, trifluoromethyl group, carbamoyl group,
Examples include sulfamoyl group and phenoxy group. When considering sensitivity and durability, the general formula ()
In, A is o-phenylene group, o-naphthylene group, perinaphthylene group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4,5
A -pyridinediyl group or a 9,10-phenanthrylene group is preferred, and as a substituent, an alkyl group, an alkoxy group, a carboxyl group, a hydroxy group, a nitro group, and a halogen atom are preferred. Specific examples of the above-mentioned bisazo compounds used in the present invention include the following.
However, the bisazo compound in the present invention is not limited to these compounds.

【table】

[Table] The above bisazo compounds used in the present invention are:
For example, the diamine represented by the above general formula () is tetrazotized by a conventional method and coupled with the compound represented by the above general formula () in the presence of an alkali, or the diamine represented by the above general formula () is After isolating the tetrazonium salt of the diamine in the form of a borofluoride salt or a zinc chloride double salt, in the presence of an alkali in a suitable solvent (e.g. N,N-dimethylformamide, dimethyl sulfoxide, etc.), It can be synthesized by coupling with a compound represented by (). In the present invention, the above-mentioned bisazo compound is contained in a photosensitive layer provided on a conductive support, but the photosensitive layer may have a single layer structure or may be functionally separated into a charge generation layer and a charge transport layer. It may also have a laminated structure. The electrophotographic photoreceptor of the present invention includes, for example, (1) a photosensitive layer formed by dispersing a bisazo compound in a binder resin containing a charge transport substance on a conductive support; (2) a conductive support; A photosensitive layer comprising a bisazo compound and a charge transfer complex dispersed in a binder resin is provided on a support, and (3) a charge generation layer containing a bisazo compound and a charge transport substance are provided on a conductive support. It can be roughly divided into those provided with a charge transport layer containing. Examples of the conductive support in the electrophotographic photoreceptor of the present invention include a metal plate made of aluminum, nickel, chromium, stainless steel, etc., a metal drum, or a plastic film provided with a metal foil and a thin film of metal or other conductive substance. Paper or plastic film coated with or impregnated with a conductivity imparting agent is used. In the present invention, when the bisazo compound is dispersed in the binder resin in the photosensitive layer formed on the conductive support, the bisazo compound is
Hereinafter, it is preferably dispersed as fine particles with a particle size of 0.3 μ or less, and the amount of blending is determined relative to the photosensitive layer.
Preferably, the content is between 20% and 90% by weight. As the binder resin, polystyrene, silicone resin, polycarbonate, acrylic resin, methacrylic resin, polyester, vinyl polymer such as polyvinyl butyral, cellulose such as cellulose ester, cellulose ether, alkyd resin, etc. can be used. . Examples of the charge transport substance used in the electrophotographic photoreceptor of the present invention include N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-
3-methylidene-9-ethylcarbazole, N,
N-diphenylhydrazino-3-methylidene-9
-Methylcarbazole, p-diethylaminobenzaldehyde-N,N-diphenylhydrazone,
p-diethylaminobenzaldehyde-N,N-
Hydrazones such as di(p-methoxyphenyl)hydrazone, p-diethylaminobenzaldehyde-N-(α-naphthyl)-N-phenylhydrazone, β,β-di(4-methoxyphenyl)acrolein diphenylhydrazone, 1-phenyl-
3-(p-diethylaminostyryl)-5-(p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(2)]-
3-(p-diethylaminostyryl)-5-(p-
Pyrazolines such as diethylaminophenyl)pyrazoline, 2-(p-dipropylaminophenyl)-
4-(p-dimethylaminophenyl)-5-(2-
Oxazole compounds such as chlorophenyl)oxazole, 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole, 2,
5-bis(p-diethylaminophenyl)-1,
3,4-oxadiazole, 2,5-bis(4'-
diethylamino-2'-methylphenyl)-1,3,
Oxadiazole compounds such as 4-oxadiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, triphenylamine, 2,4′,4″-
Triarylamine compounds such as trimethyltriphenylamine, 1,1-bis[4'-N,N-di(p-methylphenyl)aminophenyl]cyclohexane, anthracene compounds such as 5-(p-diethylaminostyrylanthracene), α -Phenyl-4'-N,N-diphenylaminostilbene, 4'-N,N-di(p-methoxyphenyl)aminostilbene and other stilbene compounds, N,
N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine, 3,3'-dimethyl-N,N,N',N'- Examples include benzidine compounds such as tetrakis(4-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine, which are incorporated into the binder resin. Furthermore, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole,
Photoconductive polymers include polyvinylanthracene, poly-9-vinylphenylanthracene, polyvinylpyrene, polyvinylacridine, polyvinylacenaphthylene, polyglycidylcarbazole, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, etc. It may also form a layer by itself. In the present invention, it is preferable that the photosensitive layer has a laminated structure because the sensitivity of the electrophotographic photoreceptor is high and the residual potential is low. In this case, the charge generation layer may be formed by dispersing the azo compound in the binder resin as described above, but it may also be formed by sublimation or vapor deposition of the bisazo compound. Further, either a charge generation layer or a charge transport layer may be provided as an upper layer; when a charge generation layer is provided as an upper layer, the electrophotographic photoreceptor is of a positively charged type, and when a charge transport layer is provided as an upper layer It can be used as a negatively charged type. In the electrophotographic photoreceptor of the present invention, an adhesive layer may be provided between the photosensitive layer and the conductive support.
The adhesive layer is made of commonly used synthetic resin such as polyester, and is usually formed to have a thickness of about 0.5 to 5 μm. Examples Hereinafter, the present invention will be explained using examples. Example 1 1 part by weight of polyvinyl butyral resin (trade name: BLX manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 40 parts by weight of cyclohexanone, 3 parts by weight of Exemplified Compound No. 1 was mixed therein, and then poured into a paint shaker. The mixture was well dispersed and applied onto an aluminum sheet using an applicator and dried to form a charge generation layer. The film thickness after drying was 0.2 μm. N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,
1 part by weight of 1'-biphenyl]-4,4'-diamine,
Polycarbonate resin (product name: Lexan 145,
A homogeneous solution consisting of 1 part by weight (manufactured by GE, molecular weight 35,000-40,000) and 15 parts by weight of dichloromethane was applied with an applicator and dried to form a charge transport layer. The film thickness was 20 μm. The thus obtained electrophotographic photoreceptor was tested using an electrostatic copying paper tester (SP-
428), the following characteristics were evaluated. first,
After applying −6KV corona charging and negatively charging,
Leave it in the dark for 2 seconds, then the surface potential Vpo
(volt), then irradiate the surface with light using a tungsten lamp so that the illumination intensity is 5 lux, find the time until the surface potential becomes 1/2 of Vpo, and calculate the exposure amount E1 /2 (lux・sec) was calculated. Furthermore, similar measurements were repeated 20 times. The results are shown in Table 1.

[Table] Examples 2 to 5 Example 1 except that Exemplified Compound No. 2, 3, 9, or 12 (Examples 2 to 5, respectively) was used instead of Exemplified Compound No. 1 in Example 1. An electrophotographic photoreceptor was prepared in the same manner as above, and its characteristics were evaluated. The results are shown in Table 2.

[Table] Comparative Examples 1 and 2 In Example 1, except that a compound represented by the following structural formula (1) or (2) (Comparative Example 1 or 2, respectively) was used instead of Exemplified Compound No. 1, Example 1
An electrophotographic photoreceptor was prepared in the same manner as above, and its characteristics were evaluated. The results are shown in Table 3.

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[Table] It can be seen that the product exhibits excellent electrophotographic properties even when compared with conventionally proposed azo pigments. Effects of the Invention Since the electrophotographic photoreceptor of the present invention is constructed using the bisazo compound, it has better sensitivity and durability than electrophotographic photoreceptors using conventional organic photoconductive substances. It has become excellent.

Claims (1)

[Claims] 1. On a conductive support, a compound of the following general formula [formula] (where A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring) .) An electrophotographic photoreceptor comprising a photosensitive layer containing a bisazo compound represented by: