JPH0820740B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photoreceptor for electrophotography, and more particularly, to a photoreceptor containing a bisazo pigment as a substance that generates charge carriers when irradiated with light (hereinafter referred to as “charge generation substance”). The present invention relates to an electrophotographic photosensitive member provided with a photosensitive layer.

2. Description of the Related Art As an electrophotographic photoconductor, an inorganic photoconductor using selenium and its alloy, a photoconductor in which dye-sensitized zinc oxide is dispersed in a binder resin, or an organic photoconductor is used. Typical examples include those using a charge transfer complex of 2,4,7-trinitro-9-fluorenone (hereinafter referred to as “TNF”) and poly-N-vinylcarbazole (hereinafter referred to as “PVK”). ing.

However, these photoreceptors have many advantages and, at the same time, have various drawbacks. For example, selenium photoconductors that are widely used at present have difficult manufacturing conditions, are expensive to manufacture, are difficult to process into a belt because they are not flexible, and are sensitive to heat and mechanical shock. Therefore, handle with care. Zinc oxide photoconductor can be manufactured by applying it to a support using inexpensive zinc oxide, but the cost is low, but generally sensitivity is low, surface smoothness, hardness, tensile strength, abrasion resistance, etc. There is a mechanical defect, and there are many problems in durability as a photoreceptor for a plain paper copying machine which is usually used repeatedly. Further, a photoconductor using a charge transfer complex of TNF and PVK has low sensitivity and is not suitable as a photoconductor for a high speed copying machine.

In recent years, extensive research has been conducted in order to eliminate the drawbacks of these photoconductors, and in particular, various organic photoconductors have been proposed. Above all, a laminated type photoreceptor in which a thin film of an organic pigment is formed on a conductive support (charge generation layer) and a layer (charge transfer layer) mainly containing a charge transfer substance is formed on the conductive support is a conventional organic material type. Compared with the photoconductor of No. 1), it is attracting attention as a photoconductor for a plain paper copying machine because of its high general sensitivity and stable charging property, and some of them have been put to practical use.

This type of conventional laminated-type photoreceptor (1) a thin layer obtained by vacuum-depositing a perylene derivative as a charge generation layer and an oxadiazole derivative as a charge transport layer (see USP 3871882) (2) A thin layer formed by coating an organic amine solution of chlordian blue is used as the charge generation layer, and a hydrazone compound is used as the charge transport layer (see Japanese Patent Publication No. 55-42380). (3) Di as the charge generation layer It is known that a thin layer formed by coating an organic solvent dispersion liquid of a styrylbenzene-based bisazo compound is used and a hydrazone compound is used for a charge carrier layer (see JP-A-55-84943).

However, it is a fact that even the laminated type photoreceptor of this type has many advantages and various drawbacks at the same time. That is, it has the following drawbacks.

Although the photoreceptor using the perylene derivative and the oxadiazole derivative shown in (1) has no problem in practical use,
Low sensitivity for higher speed copiers. Further, the perylene derivative, which is a charge generating substance that controls the spectral sensitivity of this photoconductor, is not suitable as a photoconductor for a color copying machine because it does not absorb over the entire visible range.

The photoconductor using chlordian blue and the hydrazone compound shown in (2) needs to use an organic amine (for example, ethylenediamine) which is generally difficult to handle as a coating solvent for forming a charge generation layer although the photosensitivity is relatively high. However, there are many drawbacks in producing the photoconductor.

The photoconductor using the distyrylbenzene-based bisazo compound and the hydrazone compound shown in (3) is very advantageous in production because a charge generation layer can be easily formed by coating a dispersion of the bisazo compound. However, its sensitivity is slightly low, so that it is insufficient as a photoreceptor for a high-speed copying machine. On the other hand, in recent years, the demand for photoconductors for laser printers has increased, and development of high-sensitivity photoconductors in the wavelength range of semiconductor lasers has been particularly desired. However, the photoconductors described above have extremely high sensitivity to these semiconductor lasers. The reality is that it is low and cannot be put to practical use.

An object of the present invention is a photoconductor that overcomes the above-mentioned conventional drawbacks, has a flat sensitivity over the entire visible range and the oscillation wavelength range of a semiconductor laser, and its manufacturing method is also easy for electrophotographic and laser printer photosensitization. Intended to provide the body.

Structure The present inventor has conducted extensive studies to achieve the above-mentioned object, and as a result, a compound represented by the general formula (I) as a charge-generating substance on a conductive support, (Wherein, Ar represents a coupler residue) The present inventors have found that the object can be achieved by providing a photoconductor for electrophotography, wherein a layer containing a bisazo pigment represented by the following formula as an active ingredient is formed: Was.

Ar used for the production of the bisazo compound of the general formula (I)
Examples of the coupler represented by H include aromatic hydrocarbon compounds having a hydroxyl group such as phenols and naphthols, heterocyclic compounds having a hydroxyl group, aromatic hydrocarbon compounds having an amino group, and heterocyclic compounds having an amino group. Formula compounds, aromatic hydrocarbon compounds having a hydroxyl group and an amino group such as aminonaphthols and heterocyclic compounds, compounds having an aliphatic or aromatic enol ketone group (compounds having an active methylene group), and the like are used. Preferably, the coupler residue Ar has the following general formula (II), (III), (IV), (V), (VI), (VII),
It is represented by the general formulas (VIII), (IX), (X), (XI) and (XII).

[X, Y in the above formulas (II), (III), (IV) and (V)]
₁ , Z, m and n represent the following, respectively.

Or —NHSO ₂ —R ₃ (R ₁ and R ₂ represent hydrogen or a substituted or unsubstituted alkyl group, and R ₃ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y ₁ : Hydrogen, halogen, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, carboxy group, sulfo group, substituted or unsubstituted sulfamoyl group, or (R ₄ represents hydrogen, an alkyl group or a substituted product thereof, a phenyl group or a substituted product thereof, and Y ₂ is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or (However, R ₅ represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, a styryl group or a substituted product thereof, R ₆ represents hydrogen, an alkyl group, a phenyl group or a substituted product thereof, or R ₅ and R ₆ may form a ring together with the carbon atom bonded to them. ) Z: Hydrocarbon ring or a substituted product thereof or a heterocyclic ring or a substituted product thereof, an integer of n: 1 or 2 and an integer of m: 1 or 2] [In the formulas (VI) and (VII), R ₇ represents a substituted or unsubstituted hydrocarbon group, and X is the same as described above. ] [Wherein, R ₈ represents an alkyl group, a carbamoyl group, a carboxyl group or an ester thereof, Ar ₁ represents a hydrocarbon ring group or a substituted product thereof, and X is the same as described above. ] [In the above formulas (IX) and (X), R ₉ represents hydrogen or a substituted or unsubstituted hydrocarbon group, and Ar ₂ represents a hydrocarbon ring group or a substituted product thereof. Examples of the hydrocarbon ring of Z in the general formulas (II), (III), (IV) and (V) include a benzene ring and a naphthalene ring, and examples of the heterocyclic ring include an indole ring, a carbazole ring and a benzolane ring. And the like. Examples of the substituent in the ring of Z include a halogen atom such as a chlorine atom and a bromine atom and an alkoxy group.

The hydrocarbon ring group for Y ₂ or R ₅ is a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group or the like, and the heterocyclic group is a pyridyl group, a cenyl group, a furyl group, an indolyl group, a benzofuranyl group or a carbazolyl group. Group, a dibenzofuranyl group, and the like, and examples of the ring formed by combining R ₅ and R ₆ include a fluorene ring and the like.

Y ₂ or R ₅ hydrocarbon ring group or heterocyclic group or R ₅
And a substituent in the ring formed by R ₆ , a methyl group, an ethyl group, a propyl group, an alkyl group such as a butyl group, a methoxy group, an ethoxy group, a propoxy group,
Alkoxy group such as butoxy group, halogen atom such as chlorine atom and bromine atom, dialkylamino group such as dimethylamino group and diethylamino group, diaralkylamino group such as dibenzylamino group, halomethyl group such as trifluoromethyl group, nitro Group, cyano group, carboxyl group or ester thereof, hydroxyl group, sulfonate group such as —SO ₃ Na, and the like.

Examples of the substituted phenyl group represented by R ₄ include halogen atoms such as chlorine atom and bromine atom.

Typical examples of the hydrocarbon group for R ₇ or R ₉ include an alkyl group such as a methyl group, an ethyl group, a propyl group, and a butyl group, an aralkyl group such as a benzyl group, an aryl group such as a phenyl group, or a substituent thereof. It can be illustrated.

As the substituent in the hydrocarbon group of R ₇ or R ₉ , a methyl group, an ethyl group, a propyl group, an alkyl group such as a butyl group, a methoxy group, an ethoxy group, a propoxy group, an alkoxy group such as a butoxy group, a chlorine atom, Examples include halogen atoms such as bromine atom, hydroxyl group, and nitro group.

Typical examples of the hydrocarbon ring group in Ar ₁ or Ar ₂ include a phenyl group and a naphthyl group, and the substituents in these groups include a methyl group, an ethyl group,
Alkyl group such as propyl group and butyl group, methoxy group,
Examples thereof include alkoxy groups such as ethoxy group, propoxy group and butoxy group, halogen atoms such as nitro group, chlorine atom and bromine atom, dialkylamino groups such as cyano group, dimethylamino group and diethylamino group.

 Further, in X, a hydroxyl group is particularly suitable.

Among the above-mentioned coupler residues, those represented by the above general formulas (III), (VI), (VII), (VIII), (IX) and (X) are preferable, and among these, X in the general formula is a hydroxyl group. Are preferred. Among these, the general formula (XI) (Y ₁ and Z are the same as above.) Are preferred, and a coupler residue represented by (Z, Y ₂ and R ₂ are the same as above).

Furthermore, among the above-mentioned preferred coupler residues, the compound represented by the general formula (XIII) or (XIV) (Z, R ₂ , R ₅ and R ₆ are the same as described above, and R ₁₀ is preferably the above-mentioned substituent of Y _2. )

Specific examples of the bisazo pigment used in the present invention as described above are shown by the structural formulas as follows. For simplicity, only the structural formula of Ar as a coupler residue is shown.

By using the bisazo pigment of the present invention as described above, an extremely high-sensitivity electrophotographic photoreceptor can be easily manufactured.

The bisazo pigment of the present invention is, for example, 1,8-bis (4- (4-nitrophenyl) -1,3,5,7-octatetraene obtained by Wittig reaction, which is obtained by reducing 1,8-bis (4- Aminophenyl) -1,3,5,7-octatetraene is diazotized by a conventional method to give a tetrazonium salt, and the tetrazonium salt and the corresponding coupler are combined with a suitable organic solvent such as N,
It can be easily produced by reacting a base in N-dimethylformamide to carry out a coupling reaction. As an example, a production example of the No. 1 bisazo pigment is shown below, but other bisazo pigments can be easily produced according to this production example except that the coupler is changed.

Production example Dilute sulfuric acid consisting of concentrated sulfuric acid 7.2 ml and water 100 ml added 1,8-bis (4-
Aminophenyl) -1,3,5,7-octatetraene (6.10 g) was added, and the mixture was stirred at 60 ° C for 2 hours and rapidly cooled to -2 ° C. Then, a solution of 3.23 g of sodium nitrite in 10 ml of water was added to -5 ℃
It was added dropwise at ~ -2 ° C over 50 minutes. Then, at the same temperature, 20
After stirring for 400 minutes, 400 ml of cold water was added, a trace amount of the insoluble portion was removed by filtration, 42% hydrofluoric acid was added to the filtrate, and the precipitated crystals were filtered and dried to give the dark red tetrazonium salt of the present invention.
8.4 g (yield 82%) was obtained.

Infrared absorption spectrum (KBr tablet method): 2230 cm ^-1
The absorption due to the stretching vibration of the diazonium salt was observed. The tetrazonium salts thus obtained 0.49 g and 3
0.55 g of -hydroxy-2-naphthoic acid anilide was dissolved in 200 ml of dimethylformamide (DMF), to which a solution of 0.34 g of sodium acetate in 4 ml of water was added dropwise at room temperature over 20 minutes. After the dropwise addition, the mixture was stirred at the same temperature for 3 hours, the resulting pigment was collected by filtration, and the filtration residue was added with 250 ml of dimethylformamide.
It was washed 5 times with water and then twice with 250 ml of water. A bisazo pigment of the above compound No. 1 which is a bluish black powder after being heated and dried under reduced pressure.
0.72 g (yield 82%) of 1,8-bis [4- (2-hydroxy-3-phenylcarbamoylnaphthyl-1-azo)] phenyl-1,3,5,7-octatetraene was obtained.

Decomposition point: 276 ℃ Elemental analysis value CHN actual value 77.44 4.72 9.87 C ₅₄ H ₄₀ N ₆ O ₄ Calculated value 77.48 4.83 10.04 Visible spectrum (10% by volume ethylenediamine DMF) λmax 596nm Infrared absorption spectrum (KBr tablet method) are shown in FIG. 3 but, C = 0 stretching vibration 1675 cm ^-1, absorption based on the out-of-plane deformation vibration of transformer 995 cm ^-1 was observed.

In the electrophotographic photoreceptor of the present invention, the bisazo pigment is used as a charge generating substance in the photosensitive layer, and a typical constitution of this photoreceptor is shown in FIGS. 1 and 2.

In the photoreceptor of FIG. 1, a laminated photosensitive layer 191 including a charge generation layer 15 mainly composed of a bisazo pigment 13 and a charge carrier layer 17 mainly composed of a charge carrier substance is provided on a conductive support 11. It is a thing.

In the photoreceptor of FIG. 1, the image-exposed light passes through the charge transport layer and reaches the charge generation layer 15, and the bisazo pigment 13 in that portion generates charge, while the charge transport layer 17 charges the charge. The bisazo pigment 13 generates charges necessary for light attenuation, and the charge transfer layer 17 transfers charges.

The photoreceptor shown in FIG. 2 has a photosensitive layer 192 mainly composed of a bisazo pigment 13, a charge carrier substance and an insulating binder on a conductive support 11. Again bisazo pigment 13
Is a charge generating substance.

As another photoreceptor, the charge generation layer and the charge transport layer in FIG. 1 may be reversed.

The thickness of the photosensitive layer is as shown in FIG. 1, and the thickness of the charge generation layer 15 is preferably 0.01 to 5 μ, more preferably 0.05 to 2 μ. If this thickness is 0.01 μm or less, the generation of electric charges is not sufficient, and if it is 5 μm or more, the residual potential is high and it cannot be put to practical use. The thickness of the charge transport layer 17 is preferably 3 to 50 μm,
More preferably, it is 5 to 20 μ. If this thickness is 3 μm or less, the charge amount is insufficient, and if it is 50 μm or more, the residual potential is high and it is not practical.

The charge generation layer 15 is mainly composed of the bisazo pigment represented by the above general formula, and may further contain a binder, a plasticizer and the like. The proportion of the bisazo pigment in the charge generation layer is preferably 30% by weight or more, more preferably 50% by weight or more.

The charge transport layer 17 is mainly composed of a charge transport material and a binder, and may further contain a plasticizer and the like. The proportion of the charge transport material in the charge transport layer is 10 to 95% by weight, preferably 30 to
90% by weight. 10% by weight of charge carrier
If it is less than, the charge is hardly transported, and
If it is 95% by weight or more, the mechanical strength of the photoreceptor film is extremely poor and it cannot be put to practical use.

In the case of the photoreceptor shown in FIG. 2, the thickness of the photosensitive layer 192 is preferably 3 to 50 μ, more preferably 5 to 20 μ. The proportion of the disazo pigment in the photoreceptor 192 is preferably 50% by weight or less, more preferably 20% by weight or less, and the proportion of the charge carrier substance is preferably 10 to 95% by weight, more preferably 30 to 90% by weight. % By weight.

The gist of the present invention is to use the specific bisazo pigment represented by the general formula (I) as a charge generating substance in an electrophotographic photoreceptor, and to provide a conductive support,
As the other components such as the charge carrier substance, any of those conventionally known can be used, which will be specifically described below.

As the conductive support used in the photoreceptor of the present invention, aluminum, copper, metal plate such as zinc, a plastic sheet such as polyester, aluminum or SnO ₂ vapor-deposited conductive material, or conductive Treated paper is used.

Examples of the binder include condensation polymers such as polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, and polyacetal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and vinyl polymers such as polyacrylamide. All insulating and adhesive resins can be used.

Examples of the plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate and the like. In addition, silicone oil or the like may be added to improve the surface property of the photoreceptor.

The charge carrier material includes a hole carrier material and an electron carrier material. Examples of the hole transport material include compounds represented by the following general formulas (1) to (11).

[In the formula, R ₁₁₅ represents a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group, and R ₁₂₅ represents a methyl group, an ethyl group, a benzyl group or a phenyl group, and R
₁₃₅ is hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxyl group, a dialkylamino group or a nitro group having 1 to 4 carbon atoms. ] [In the formula, Ar ₃ represents a naphthalene ring, an anthracene ring, a styryl group and a substitution product thereof, a pyridine ring, a furan ring or a thiophene ring, and R ₁₄₅ represents an alkyl group or a benzyl group. ] [In the formula, R ₁₅₅ represents an alkyl group, a benzyl group, a phenyl group, or a naphthyl group, and R ₁₆₅ represents hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, or a diaralkyl group. Represents an amino group or a diarylamino group, n represents an integer of 1 to 4, and when n is 2 or more, R ₁₆₅ may be the same or different. R ₁₇₅ represents hydrogen or a methoxy group. ] [In the formula, R ₁₈₅ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, and R ₁₉₅ R
₂₀₅ may be the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a chloroalkyl group, a substituted or unsubstituted aralkyl group, and R ₁₉₅ and R ₂₀₅ are bonded to each other. And may form a heterocycle containing nitrogen. R ₂₁₅ may be the same or different and represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or halogen. ] [In the formula, R ₂₂₅ represents hydrogen or a halogen atom, and
₄ represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group or carbazolyl group. ] [In the formula, R ₂₃₅ is hydrogen, halogen, cyano group, carbon number 1
Represents an alkoxy group having 4 to 4 or an alkyl group having 1 to 4 carbon atoms, and Ar ₅ is R ₂₄₅ represents an alkyl group having 1 to 4 carbon atoms,
R ₂₅₅ is hydrogen, halogen, alkyl group having 1 to 4 carbon atoms, an alkoxy group or dialkylamino group having 1 to 4 carbon atoms, n is 1 or 2, R ₂₅₅ when n is 2
May be the same or different, and R ₂₆₅ and R ₂₇₅ represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group. ] [In the formula, R ₂₈₅ and R ₂₉₅ are a carbazolyl group, a pyridyl group, a cenyl group, an indolyl group, a furyl group or a substituted or unsubstituted phenyl group, a styryl group, a naphthyl group or an anthryl group, and these substituents Is selected from the group consisting of dialkylamino groups, alkyl groups, alkoxy groups, carboxy groups or esters thereof, halogen atoms, cyano groups, aralkylamino groups, N-alkyl-Naralkylamino groups, amino groups, nitro groups and acetylamino groups. Represents a radical ] Wherein R ₃₀₅ represents a lower alkyl group or a benzyl group; R ₃₁₅ represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group or an amino group substituted with a lower alkyl group or a benzyl group. And n represents an integer of 1 or 2. ] (In the formula, R ₃₂₅ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, R ₃₃₅ and R ₃₄₅ represent an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and R ₃₅₅ Represents a hydrogen atom or a substituted or unsubstituted phenyl group, and Ar
₆ represents a phenyl group or a naphthyl group. ] [In the formula, n is an integer of 0 or 1, R ₃₆₅ is a hydrogen atom, an alkyl group or a substituted or unsubstituted phenyl group, and A ₁ is Represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, wherein R ₃₇₅ is a hydrogen atom,
Alkyl group, alkoxy group, halogen atom or (However, R ₃₈₅ and R ₃₉₅ represent an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and R ₃₈₅ and R ₃₉₅ may form a ring)
m is an integer of 0, 1, 2 or 3, and when m is 2 or more, R ₃₇₅ may be the same or different. ] [In the formula, R ₄₀₅ , R ₄₁₅ and R ₄₂₅ represent hydrogen, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or 1. Examples of the compound represented by the general formula (1) include 9-ethylcarbazole-3-aldehyde, 1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-
Examples include benzyl-1-phenylhydrazone and 9-ethylcarbazole-3-aldehyde 1,1-diphenylhydrazone.

Examples of the compound represented by the general formula (2) include 4-diethylaminostyrene-β-aldehyde 1-methyl-1-phenylhydrazone and 4-methoxynaphthalene-1-aldehyde 1-benzyl-1-phenylhydrazone.

Examples of the compound represented by the general formula (3) include 4-methoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde.
1,1-diphenylhydrazone, 4-methoxybenzaldehyde 1-benzyl-1- (4-methoxy) phenylhydrazone,
4-diphenylaminobenzaldehyde 1-benzyl-1-phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone and the like.

Examples of the compound represented by the general formula (4) include 1,1-
Bis (4-dibenzylaminophenyl) propane, tris (4-diethylaminophenyl) methane, 1,1-bis (4-dibenzylaminophenyl) propane, 2,2'-dimethyl-4,4'-bis (diethylamino) ) -Triphenylmethane etc.

The compound represented by the general formula (5) includes, for example, 9-
Examples include (4-diethylaminostyryl) anthracene and 9-bromo-10- (4-diethylaminostyryl) anthracene.

Examples of the compound represented by the general formula (6) include 9-
(4-Dimethylaminobenzylidene) fluorene, 3- (9-
Fluorenylidene) -9-ethylcarbazole and the like.

Examples of the compound represented by the general formula (7) include 1,2-
There are bis (4-diethylaminostyryl) benzene and 1,2-bis (2,4-dimethoxystyryl) benzene.

Examples of the compound represented by the general formula (8) include 3-styryl-9-ethylcarbazole and 3- (4-methoxystyryl) -9-ethylcarbazole.

Examples of the compound represented by the general formula (9) include 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1- (4-diphenylaminostyryl) naphthalene, 1- (4-diethylamino). Styryl) There is naphthylene.

The compound represented by the general formula (10) includes, for example, 4 '
-Diphenylamino-α-phenylstilbene, 4'-
Examples include methylphenylamino-α-phenylstilbene.

Examples of the compound represented by the general formula (11) include 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline and 1-phenyl-3- (4-
Examples include dimethylaminostyryl) -5- (4-dimethylaminophenyl) pyrazoline.

Other hole-transporting substances include, for example, 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole and 2,5-bis [4- (4-diethylaminostyryl) phenyl]- 1,3,4-oxadiazole, 2- (9-ethylcarbazolyl-3-)-5- (4-diethylaminophenyl) -1,3,4-
Oxadiazole compounds such as oxadiazole, 2-vinyl-4- (2-chlorophenyl) -5- (4-diethylaminophenyl) oxazole, 2- (4-diethylaminophenyl) -4-phenyloxazole and other oxazole compounds There are low molecular weight compounds such as. In addition, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole,
Polymer compounds such as polyvinylpyrene, polyvinylanthracene, pyreneformaldehyde resin and ethylcarbazoleformaldehyde resin can also be used.

As the electron carrier, for example, chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,
5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,
6,8-Trinitro-4H-indeno [1,2-b] thiophen-4-
On, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, etc.

These charge carrier substances may be used alone or in combination of two or more.

In each of the photoreceptors obtained as described above, an adhesive layer or a barrier layer can be provided between the photoreceptors of the conductive support, if necessary. Polyamide, nitrocellulose, aluminum oxide and the like are suitable as materials used for these layers, and the film thickness is preferably 1 μm or less.

To prepare the photoreceptor of FIG. 1, the bisazo pigment on the conductive support is vacuum-deposited by the vacuum deposition method described in USP 3,973,959, USP 3,996,049, or fine particles of the bisazo pigment are used. If necessary, it is dispersed in a suitable solvent in which a binder is dissolved, and this is coated and dried on a conductive support, and if necessary, as disclosed in, for example, JP-A-51-90827. It is obtained by finishing the surface by a method such as buffing or adjusting the film thickness, and then coating and drying a solution containing a charge carrier substance and a binder.

To prepare the photoreceptor of FIG. 2, fine powder of a bisazo pigment is dispersed in a solution in which a charge carrier substance and a binder are dissolved, and this is coated and dried on a conductive support.

In any case, the bisazo pigment used in the present invention is pulverized with a ball mill or the like to have a particle size of 5 μm or less, preferably 2 μm or less. The coating method is carried out by a conventional means such as doctor blade, dipping, wire bar or the like.

Copying using the photoreceptor of the present invention is achieved by charging and exposing the surface of the photosensitive layer, then developing, and transferring to paper or the like, if necessary.

The electrophotographic photoreceptor of the present invention is 1,8-diphenyl-1,3,5,
By using a bisazo pigment having a 7-octatetraene skeleton as a charge generating substance, it is easier to manufacture than conventional photoconductors, and it has high sensitivity and the visible wavelength range and semiconductor laser oscillation wavelength range. It has excellent properties such as a flat sensitivity over a long period of time and stable characteristics even after repeated use of the photoconductor.

Next, the present invention will be specifically described with reference to examples, but the embodiments of the present invention are not limited thereby.

Example 1 7.5 parts by weight of bisazo pigment No. 1 and 500 parts by weight of a tetrahydrofuran solution (solid content concentration 0.5%) of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) were pulverized and mixed in a ball mill to obtain a dispersion liquid. Is applied onto the aluminum surface of a polyester base (conductive support) vapor-deposited with aluminum using a doctor blade and air-dried to a thickness of about 1μ.
m charge generating layer was formed.

On this charge generation layer, 2 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone as a charge carrier, 2 parts by weight of a polycarbonate resin (Panlite K-1300 manufactured by Teijin Ltd.) and 16 parts by weight of tetrahydrofuran The solution prepared by mixing and dissolving the parts was applied using a doctor blade and dried at 80 ° C for 2 minutes and then at 105 ° C for 5 minutes to form a charge transport layer having a thickness of about 20 µm, and the laminated type shown in Fig. 1 was used. No.1 photoconductor was created.

Examples 2 to 25 Instead of the bisazo pigment No. 1 used in Example 1, the following table-
Photoreceptor Nos. 2 to 25 were prepared in the same manner as in Example 1 except that the bisazo pigment shown in 1 was used.

Examples 26 to 40 Example 1 except that 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline was used as the charge carrier substance and the bisazo pigment shown in Table 2 below was used. Photoreceptor Nos. 26 to 40 were prepared in the same manner as in.

Examples 41 to 55 In the same manner as in Example 1, except that α-phenyl-4′-N, N-diphenylaminostilbene was used as the charge carrier substance and the bisazo pigment shown in Table 3 below was used, the photoreceptor No. Four
Created 1-55.

Examples 55 to 65 In the same manner as in Example 1 except that 1,1-bis (4-dibenzylaminophenyl) propane was used as the charge carrier substance and the bisazo pigment shown in Table 4 below was used, the photoreceptor No. .56
~ 65 created.

These photoconductors Nos. 1 to 65 were tested using an electrostatic copying paper tester (SP 428 type manufactured by Kawaguchi Electric Co., Ltd.)
After performing 6KV corona discharge for 20 seconds to make it negatively charged, leave it in the dark for 20 seconds, and then surface potential Vpo (V)
Then, a tungsten lamp is used to irradiate the surface with light having an illuminance of 4.5 lux and the time (sec) until the surface potential becomes 1/2 of Vpo is obtained. Looks seconds) was calculated. Table of the results
1 to Table 4 are shown.

Comparative Example 1 A laminated-type photoreceptor was prepared as described in U.S. Pat. No. 3,871,882, in which a perylene derivative was used as the charge generation layer and an oxadiazole derivative was used as the charge transport layer as follows.

N, N'-dimethylperylene-3,4, as a charge generating substance
9,10-Tetracarboxylic acid diimide was vacuum-deposited on an aluminum plate under the conditions of a vacuum degree of 10 ⁻⁵ mmHg, an evaporation source temperature of 350 ° C., and an evaporation time of 3 minutes to form a charge generation layer. Next, on this charge generation layer, 5 parts by weight of 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, polyester resin (made by DuPont, polyester adhesive swab)
49000) 5 parts by weight and 90 parts by weight of tetrahydrofuran are applied and dried at 120 ° C for 10 minutes to give a thickness of about 10
A comparative photoconductor No. 1 was prepared by forming a charge generation layer of μm.

Comparative Example 2 A laminated type photoreceptor described in JP-B-55-42380 was prepared as follows, using chlordian blue as a charge generation layer and using a hydrazone compound as a charge transport layer.

Chlordian blue 25 parts by weight, ethylenediamine 12
A solution of 40 parts by weight, 990 parts by weight of n-butylamine and 2740 parts by weight of tetrahydrofuran was wet-deposited on the aluminum surface of the polyester base on which aluminum was vapor-deposited to have a wet gap of 25 μm.
Then, it was applied using a doctor blade and dried to form a charge generation layer. Then, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone 10 was formed on the charge generation layer.
A solution of 10 parts by weight, 10 parts by weight of a polycarbonate resin (the same as the resin used in Example 1) and 80 parts by weight of tetrahydrofuran was applied using a doctor blade and dried to form a charge transport layer having a thickness of about 18 μm. Then, a laminated type comparative photoconductor No. 2 was prepared.

Comparative Example 3 A laminated type photoreceptor described in JP-A-55-84943, which uses a distyrylbenzene-based bisazo compound as a charge generation layer and a hydrazone compound as a charge transport layer, is prepared as follows. Created.

4,4 ″ -bis [2-hydroxy-3- (2,4-dimethylphenylcarbamoyl) -1-naphthylazo] -1,4-distyrylbenzene 20 parts by weight, polyvinyl butyral (Tokyo Denki Kagaku Denka Butyral # 4000-1) 3 parts by weight, polymethylmethacrylate (Dianal manufactured by Mitsubishi Rayon Co., Ltd.
BR-80) 7 parts by weight and tetrahydrofuran 300 parts by weight,
After milling for 3 hours in a ball mill, this dispersion was diluted with 2700 parts by weight of tetrahydrofuran, and then applied to the aluminum surface of the aluminum-deposited polyester base (conductive support) using a doctor blade, and dried to a thickness of about 0.3 μm
The charge generation layer of was formed. Then, on this charge generation layer, 9-ethylcarbazole-3-aldehyde 1-methyl-1-
A solution of 10 parts by weight of phenylhydrazone, 10 parts by weight of a polycarbonate resin (the same as the resin used in Example 1) and 80 parts by weight of tetrahydrofuran was applied using a doctor blade and dried to obtain a charge having a thickness of about 13 μm. A transport layer was formed to prepare a laminated type comparative photoconductor No. 3.

These comparative photoconductors Nos. 1 to 3 and the photoconductor No. 12 of the present invention
The following measurements were performed to investigate the sensitivity to long-wavelength light.

First, the surface potential of the photoconductor is charged to -800 V or more by corona discharge in the dark, and is dark-attenuated until the surface potential reaches -800 V. At the time when the surface potential shows -800 V, the monochromator. Was used to irradiate the photoconductor with monochromatic light having an intensity of 1 μW / cm ² on the photoconductor surface, which was dispersed at 780 nm. Then, the time (sec) until the surface potential decays to -400 V is calculated, and the half-exposure amount (μW · sec / c
m ² ) was calculated. On the other hand, the potential difference actually obtained by exposure is calculated by subtracting the potential attenuation due to dark decay from the apparent potential difference of 400 V obtained by exposure, and the light decay rate (V ·cm
² · μJ ^-1 ) was calculated and used as the sensitivity.

The measurement results are shown in Table 5 below. Photoconductor No. Light decay speed (V · cm ² · μJ ⁻¹ ) Inventive photoreceptor No. 12 580 Comparative photoreceptor No. 1 10 or less Comparative photoreceptor No. 2 10 or less Comparative photoreceptor No. 3 10 or less Effect Table 1 As is clear from the results shown in Table 5, the photoconductor of the present invention has high sensitivity and also has extremely excellent sensitivity in the oscillation wavelength region (780 nm) of the semiconductor laser. Also, when preparing the photoconductor, the comparative photoconductor N
Unlike the case of o.1 and the comparative photoconductor No. 2, there is no need to perform vapor deposition or use an organic amine, which is advantageous in manufacturing.

Furthermore, the photoconductor No. 12 of the present invention was mounted on a copying machine Recopy FT-4700 manufactured by Ricoh Co., Ltd., and image output was repeated 10,000 times. As a result, any of the photoconductors was changed by repeating the copying process. And a clear image was obtained. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief description of drawings]

1 and 2 are enlarged cross-sectional views showing a constitutional example of the photoconductor of the present invention. FIG. 3 shows a bisazo pigment used in the present invention.
It is the infrared absorption spectrum of No. 1 (KBr tablet method). 11 ... Conductive support, 13 ... Bisazo pigment 15 ... Charge generation layer, 17 ... Charge transport layer 191, 192 ... Photosensitive layer

Claims (1)

[Claims] 1. A compound of general formula (I) on a conductive support. (Wherein Ar represents a coupler residue). A photoreceptor for electrophotography, wherein a layer containing a bisazo pigment represented by the following formula as an active ingredient is formed.