JPH0515260B2 - - 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 Conventionally, inorganic photoconductive substances such as amorphous selenium, selenium alloys, cadmium sulfide, and zinc oxide, and organic photoconductive substances such as polyvinyl carbazole and polyvinyl carbazole derivatives have been used as electrophotographic photosensitive materials. is widely known. Compared to inorganic photoconductive materials, organic photoconductive materials are
It has the advantage of being excellent in terms of transparency, film-forming properties, flexibility, manufacturability, etc. Problems to be Solved by the Invention Despite having such many advantages, organic photoconductive materials have not been used in electrophotographic photoreceptors because inorganic photoconductors have poor sensitivity and durability. It was to be inferior. Therefore, the present invention has been made in view of the above-mentioned drawbacks when using an organic photoconductive substance, and its purpose is to provide an electrophotographic photoreceptor with high sensitivity and high durability. It's about doing. Means for Solving the Problems The electrophotographic photoreceptor of the present invention is characterized in that the photosensitive layer on the conductive support contains an azo compound represented by the following general formula () or (). (In the formula, A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring, and Ar represents an aromatic hydrocarbon group or a heterocyclic group that may be bonded via a bonding group. (n represents an integer of 1, 2, 3 or 4) Hereinafter, the present invention will be explained in detail. To further explain the azo compound represented by the general formula () used in the electrophotographic photoreceptor of the present invention, in the general formula (), A is a divalent aromatic hydrocarbon group or a divalent aromatic hydrocarbon group containing a nitrogen atom in the ring. Examples of the divalent aromatic hydrocarbon group include a divalent monocyclic aromatic hydrocarbon group such as an o-phenylene group, an o-naphthylene group,
Examples include divalent condensed polycyclic aromatic hydrocarbon groups such as perinaphthylene group, 1,2-anthraquinonyl group, and 9,10-phenanthrylene group. In addition, as a divalent heterocyclic group having a nitrogen atom in the ring,
3,4-pyridinediyl group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4,5-
Examples include heterocyclic groups such as pyrimidinediyl group, 5,6-benzimidazolediyl group, and 6,7-quinolinediyl group. The divalent aromatic hydrocarbon group and the divalent heterocyclic group containing a nitrogen atom in the ring may have a substituent. As a substituent, C ₁ to C ₁₈
alkyl group, _C1 - _C4 alkoxy group, _C1 - _C4
Examples include an alkoxycarbonyl group, a carboxyl group, a hydroxy group, a nitro group, a cyano group, a halogen atom, a trifluoromethyl group, a carbamoyl group, a sulfamoyl group, and a phenoxy group. Considering sensitivity and durability, A is:
o-phenylene group, o-naphthylene group, perinaphthylene group, 2,3-pyridinediyl group, 3,4-
Those representing a pyridinediyl group, 4,5-pyrimidinediyl group, and 9,10-phenanthrylene group are preferred, and as the substituent, an alkyl group, an alkoxy group, a carboxyl group, a hydroxy group, a nitro group, and a halogen atom are preferred. In the general formula (), Ar represents an aromatic hydrocarbon group or a heterocyclic group which may be bonded via a bonding group, and preferable examples include a phenyl group, a naphthyl group, a 1-pyrenyl group, and a 2-pyrenyl group. - Monovalent monocyclic or fused polycyclic aromatic hydrocarbon groups such as anthryl group, 5-acenaphthenyl group, 2-fluorenonyl group, 1- or 2-anthraquinonyl group,
Phenylene group, 1,5- or 2,7-naphthylene group, 1,4-, 1,5- or 2,6-anthraquinonylene group, 2,4- or 2,7-fluorenonylene group, 2,7- Fluorenylene group, pyrenylene group, 2,7-phenanthraquinonylene group, 2,7
-(9-dicyanomethylene)fluorenonylene group,
Divalent monocyclic or fused polycyclic aromatic hydrocarbon groups such as dibenzotropondiyl group, dicyanomethylene dibenzotropondiyl group, benzantroninolene group, bivalent polycyclic group such as biphenylene group or binaphthylene group Aromatic hydrocarbon group, divalent group represented by the following formula (In the formula, Y is -O-, -S-, -SS-, -SO-,
−SO ₂ −, −NH−,

[Formula] -CO-,

[Formula] −CONH−, −CH ₂ −, −CH= CH−,

[Formula] -N=N-, -C≡C-,

【formula】

【formula】

【formula】

[Formula] −CH=CH−CH=CH− −CH=N−N=CH
− or ), a trivalent group derived from triphenylamine, triphenylmethane, terphenylfluorenone, etc., a tetravalent group derived from tetraphenylbenzidine, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, Monovalent heterocyclic groups such as carbazolyl group and quinolyl group, 2-phenylbenzoxazolediyl group, 2-phenylbenzimidazolediyl group, carbazolediyl group, 2-phenylbenzothiazolediyl group, 2-phenylbenzo triazolediyl group,
dibenzothiophenediyl group, dibenzothiophenoxidediyl group, 9-acridonediyl group,
Divalent heterocyclic groups such as xanthonediyl group and phenoxazinediyl group, trivalent heterocyclic group derived from triphenylpyridine, triphenyltriazole, N-phenylcarbazole, N-phenylphenoxazine, etc. etc. can be mentioned. Particularly preferred Ar is a phenyl group,
naphthyl group, pyrenyl group, fluorenonyl group, anthraquinonyl group, naphthylene group, anthraquinonylene group, fluorenonylene group, pyrenylene group,
9-dicyanomethylenefluorenonylene group, dibenzotropondiyl group, biphenylene group, divalent group represented by the following general formula, (In the formula, Y is -O-, -S-,

[Formula] −CH ₂ −, −CH=CH−,

[Formula]-N= N-,

【formula】

or ), 3 derived from triphenylamine
tetravalent group derived from tetraphenylbenzidine, 2-phenylbenzoxazolediyl group, 2-phenylbenzimidazolediyl group, carbazolediyl group, 9-acridonediyl group, xanthonediyl group, Examples thereof include an enoxazinediyl group, and trivalent groups derived from N-phenylcarbazole, N-phenyphenoxazine, and the like. Specific examples of the azo compounds used in the present invention include the following. However, the azo compound in the present invention is not limited to these compounds.

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] The above disazo compounds used in the present invention are:
For example, the corresponding diamine is tetrazotized by a conventional method and coupled with a coupler represented by the general formula H-Cp in the presence of an alkali, or the tetrazonium salt of the corresponding diamine is converted into a borofluoride salt or a zinc chloride double salt. It can be synthesized by isolating the compound as a form and then coupling it with the above coupler in a suitable solvent (eg, N,N-dimethylformamide, dimethyl sulfoxide, etc.) in the presence of an alkali. In the present invention, the above-mentioned azo 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 an azo compound in a binder resin containing a charge transport substance on a conductive support;
(2) A photosensitive layer formed by dispersing an azo compound and a charge transfer complex in a binder resin on a conductive support, and (3) A charge generating layer containing an azo compound on a conductive support. It can be broadly classified into those provided with a charge transport layer and a charge transport layer containing a charge transport material. 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 azo compound is dispersed in the binder resin in the photosensitive layer formed on the conductive support, the azo compound is dispersed as fine particles with a particle size of 3μ or less, preferably 0.3μ or less. The compounding amount is preferably 20% to 90% by weight based on the photosensitive layer. 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. . As the charge transport material used in the electrophotographic photoreceptor of the present invention, for example, 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-di(p-methoxyphenyl)hydrazone, p
-diethylaminobenzaldehyde-N-(α-
naphthyl)-N-phenylhydrazone, β, β-
Hydrazones such as 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
-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole, and other oxazole compounds;
2,5-bis(p-diethylaminophenyl)-
1,3,4-oxadiazole, 2,5-bis(4'-diethylamino-2'-methylphenyl)-
Oxadiazole compounds such as 1,3,4-oxadiazole, bis(4-diethylamino-2-
Triarylmethane compounds such as methylphenyl)-phenylmethane, triphenylamine, 2,
4′,4″-trimethyltriphenylamine, 1,1
-bis[4'-N,N-di(p-methylphenyl)
triarylamine compounds such as [aminophenyl]cyclohexane, anthracene compounds such as 5-(p-diethylaminostyrylanthracene),
Stilbene compounds such as α-phenyl-4′-N,N-diphenylaminostilbene, 4′-N,N-di(p-methoxyphenyl)aminostilbene,
N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-
Diamine, 3,3'-dimethyl-N,N,N',
N'-tetrakis(4-methylphenyl)-[1,
Examples include benzidine compounds such as 1'-biphenyl]-4,4'-diamine, which are incorporated into the binder resin. Furthermore, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylanthracene, poly-9-vinylphenylanthracene, polyvinylpyrene,
Examples include photoconductive polymers such as polyvinylacridine, polyvinylacenaphthylene, polyglycidylcarbazole, pyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin, which may form a layer by themselves. 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 azo 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 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 mixed in a paint shaker. After being well dispersed, this was 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 electrophotographic photoreceptor thus obtained 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 check 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 10 In Example 1, Exemplary Compound No. 2, 3, 14, 15, 16, 27, 28, 33,
Electrophotographic photoreceptors were produced in the same manner as in Example 1, except that 42 (Examples 2 to 10, respectively) were used, and their characteristics were evaluated. The results are shown in Table 2.

[Table] Effects of the Invention Since the electrophotographic photoreceptor of the present invention is constructed using the azo compound, it has better sensitivity and durability than electrophotographic photoreceptors using conventional organic photoconductive substances. It is superior in terms of sex.

Claims (1)

[Claims] 1. The following general formula () or () is formed on a conductive support. (In the formula, A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring, and Ar represents an aromatic hydrocarbon group or a heterocyclic group that may be bonded via a bonding group. An electrophotographic photoreceptor comprising a photosensitive layer containing an azo compound represented by: