JP3509218B2 - Electrophotographic photoreceptor - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor. More specifically, the present invention relates to a highly sensitive electrophotographic photoreceptor containing a novel azo compound.

[0002]

2. Description of the Related Art Conventionally, as a photoconductor for electrophotography, a photoconductor using an inorganic photoconductive substance such as selenium, cadmium sulfide, zinc oxide or the like has been used, but recently, it is manufactured as a non-polluting product. The organic photoconductive compound (OPC) has many advantages such as easy handling, good image quality, and easy production of photoconductors of various shapes such as drums, sheets and belts. ), So-called OPC
Photoconductors have come to be used in plain paper copiers (PPCs) and printers, and the proportion thereof is increasing year by year. OPC photoconductors have many advantages over conventional inorganic photoconductors.

Many attempts have been made as means for improving the sensitivity and durability of OPC photoconductors. The first commercially available OPC photoreceptor was polyvinylcarbazole (PV
It was a photoconductor utilizing the sensitizing action of the charge transfer complex formed by mixing K) with 2,4,7-trinitrofluorenone (TNF) which is an electron-withdrawing compound.

However, since then, many charge transfer complex type OPC photoconductors have been developed. PVK-TNF
The ones that outperform the photoconductors have not been put to practical use. Presently mainly used are photoreceptors called function-separated type in which the functions of generating and transporting charge carriers are separated and shared by different compounds. The function-separated photoreceptor is
It is possible to combine a compound with high charge carrier generation efficiency and a compound with high transport efficiency. Furthermore, a wide selection of materials with excellent durability, high sensitivity and excellent durability of the photoreceptor It is a type that can be obtained.

As the form of the function-separated type photoreceptor, there are two types, that is, a laminated type in which a carrier-generating material and a carrier-transporting material are separated into separate layers and laminated, and a single-layer type contained in the same photosensitive layer. In either case, however, the process in which the carrier-generating material absorbs light to generate a carrier, injects the generated carrier into the carrier-transporting material, and the carrier moves between the molecules of the carrier-transporting material in the photoreceptor. Has been. Therefore, the sensitivity of the photoreceptor depends on the carrier generation efficiency, injection efficiency, and transport efficiency, and the carrier generation material having high generation efficiency and the carrier transportation material having high transportation efficiency, and the carrier generation material and the transportation material having high injection efficiency are determined. A combination has been selected.

Various photoconductive pigments have been developed as carrier generating materials. Since it has high sensitivity and suitable spectral sensitivity as compared with other pigments for PPC, many azo pigments have been studied and put into practical use, and some examples of high sensitivity have been reported. However, from the viewpoint of durability, conventional azo pigments generally have a large light fatigue, and cannot be said to be sufficient.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide OPC.
It is to provide a photoconductor having both improved sensitivity and durability, which are problems of the photoconductor, and in particular, it has high sensitivity and very little light fatigue, and has little deterioration in electrostatic characteristics due to repeated use and durability. To provide an excellent OPC photosensitive member.

[0008]

As an azo pigment used as a carrier-generating material, a bisazo pigment having a naphthol AS type coupler residue has been mainly studied, including JP-A-47-37543. However, the azo pigment having this type of coupler residue is generally disadvantageous in that it has a large light fatigue property and is inferior in the durability of electrostatic properties.

In order to obtain a highly sensitive and highly durable electrophotographic photoreceptor, the present inventors have conducted various studies on new azo compounds as carrier generating materials, and as a result, azo compounds having a specific coupler are preferred. Is found,
The present invention has been reached. That is, the gist of the present invention resides in an electrophotographic photoreceptor containing an azo compound having a coupler component represented by the following general formula (1) on a conductive substrate.

[0010]

[Chemical 5] (In the formula, X is O, NH or

[0011]

[Chemical 6]

Represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, a cyano group, a nitro group, an alkoxycarbonyl group or an alkylaminocarbonyl group, and Z represents a substituent. Optionally represents a heterocyclic group, and ring Q represents a hydrocarbon-based aromatic ring which may have a substituent or an aromatic heterocycle which may have a substituent. ) Preferably, an azo compound represented by the following general formula (2) is used.

[0013]

[Chemical 7]

(In the formula, Ar represents an aromatic hydrocarbon group, a heterocyclic group or a group in which they are bonded via a bonding group,
n represents a number of 1, 2, 3 or 4, and X, Y, Z and Q are the same as in the general formula (1). ) More preferably, an azo compound represented by the following general formula (3) is used.

[0015]

[Chemical 8]

(In the formula, at least one of the couplers A and B represents a residue of the coupler component represented by the general formula (1), and D represents a carbon atom to which an azo group is bonded to form a double bond. A divalent group which is a carbon atom of SP ² type is shown.)

The azo compound of the present invention will be described in detail below.
In the coupler component of the general formula (1), Y is a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; a methyl group, an ethyl group, an n-propyl group, an i-propyl group, Alkyl group such as n-butyl group, i-butyl group and n-hexyl group, preferably alkyl group having 1 to 4 carbon atoms; substituted alkyl group such as trifluoromethyl group; cyano group; nitro group; methoxycarbonyl group, An alkoxycarbonyl group such as an ethoxycarbonyl group, preferably an alkoxycarbonyl group having 1 to 4 carbon atoms; an alkylaminocarbonyl group such as a methylaminocarbonyl group or an ethylaminocarbonyl group, preferably an alkylaminocarbonyl group having 1 to 4 carbon atoms Can be mentioned.
Z represents a heterocyclic substituent which may have a substituent, and the heterocyclic substituent may be a thienyl group,
Benzothienyl group, benzofuryl group, benzopyrrolyl
Group, pyridyl group, benzothiazolyl group, benzoxazolyl group, benzimidazolyl group, benzopyrimidone group,
Naphthopyrimidone group can be mentioned, and these substituents include an alkyl group such as a methyl group, an ethyl group and a butyl group; a halogen atom such as fluorine, chlorine, bromine and iodine; an alkoxy group such as a methoxy group, an ethoxy group and a butoxy group. An aryloxy group such as a phenoxy group; a hydroxy group; a nitro group;
Cyano group; amino group; substituted amino group such as dimethylamino group, diethylamino group, dibenzylamino group; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; aryloxycarbonyl group such as phenyloxycarbonyl group; acetoxy group, benzoyl An acyloxy group such as an oxy group; an acyl group such as an acetyl group and a benzoyl group; a substituted aminocarbonyl group such as a carbamoyl group, a dimethylaminocarbonyl group and a phenylaminocarbonyl group; and an arylalkoxy group such as a benzyloxy group and a phenethyloxy group. To be

[0018] Examples of the ring Q, benzene ring, naphthalate down ring, a pyridine ring, a quinoline ring, indole ring, Chianafu
Examples thereof include a hydrocarbon-based aromatic ring of a tolene ring and a hetero-based aromatic ring, which may have the same substituents as Z. In the general formula (2), Ar is 1 to 4
It represents an aromatic hydrocarbon group or a heterocyclic group which may be bonded via a valent bonding group.

As the aromatic hydrocarbon group, for example, monovalent monocyclic or condensed polycyclic aromatic hydrocarbon such as phenyl group, naphthyl group, 1-pyrenyl group, 2-anthryl group, 5-acenaphthenyl group and the like. Group; monocyclic or condensed polycyclic aromatic hydrocarbon such as phenylene group, 1,3- or 1,4-naphthylene group, 2,6-anthraquinonylene group, 2,7-fluorenylene group, pyrenylene group Divalent group: Other bivalent group such as biphenylene group. The aromatic hydrocarbon group bonded through a bonding group has the general formula

[0020]

[Chemical 9]

Examples thereof include divalent groups such as bisphenylene group, xanthonylene group and fluorenonylene group; and trivalent groups derived from triphenylamine, triphenylmethane, 9-phenylfluorene and the like. Further, as the heterocyclic group, a naphtholine benzimidazolyl group, a benzimidazolyl group, a benzoxazolyl group,
Carbazolyl group, benzothiazolyl group, quinolyl group and other 9- to 20-membered heterocyclic monovalent groups; carbazolediyl group, benzothiophenediyl group, dibenzothiophenediyl group, benzothiophene oxidediyl group, etc.
20-membered heterocyclic divalent group; trivalent group such as N-phenylcarbazoletriyl group and triphenylamine-triyl group; tetraphenylethylenetetrayl group, p, p'-
A tetravalent group such as a diphenylamino-stilbene-tetrayl group may be mentioned.

Considering sensitivity and durability, phenyl group, naphthyl group, birenyl group, naphthylene group, anthraquinonylene group, biphenylene group, general formula

[0023]

[Chemical 10]

A bisphenylene group represented by: naphtholine benzimidazolyl group, particularly

[0025]

[Chemical 11] Is preferred.

In the present invention, these aromatic hydrocarbon group and heterocyclic group may have a substituent. Specifically, nitro group; cyano group; halogen atom such as chlorine atom and bromine atom; methyl group, ethyl group, n-propyl group, 1-
Alkyl group such as butyl group; alkoxy group such as methoxy group, ethoxy group, propoxy group; aryl group such as phenyl group; arylamino group such as phenylamino group; aryloxy group such as phenoxy group; styryl group, naphthylvinyl group And aryl vinyl groups. Of these, a nitro group, a cyano group, a methyl group, a methoxy group and a chlorine atom, particularly a nitro group and a cyano group are preferable.

In the azo compound represented by the general formula (3),
A represents a coupler residue in which the coupler component of the general formula (1) is bonded to a diazonium salt by a coupling reaction, B represents a residue of a coupler having a phenolic hydroxyl group which is the same as or different from A, and represents a diazonium salt. Any coupler can be used for the coupling reaction.

The phenolic hydroxyl group is a hydroxyl group substituted on an aromatic hydrocarbon ring, and the aromatic hydrocarbon ring may be further condensed with a hydrocarbon ring or a heterocycle. As B, the same general formula (1) coupler as A or a different general formula (1) coupler can be used, but in particular, the following general formulas (4-a) to (4-m)
The residue of the coupler represented by is preferred.

[0029]

[Chemical 12]

(In the above formula, Y ₁ and Y ₂ are each independently a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an aryl group, a heterocyclic group, an alkoxy group or an aryloxy group. Represents a group, an aralkyloxy group, a carboxyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted hydrazinocarbonyl group, an acyl group, or an acylamino group.)

[0031]

[Chemical 13]

(In the above formula, Y ₃ is a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an aralkyloxy group or a carboxyl group. Represents a group, an alkoxycarbonyl group, an aryloxycarbonyl group or an acyl group, and P represents a divalent group required for being condensed with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle.)

[0033]

[Chemical 14]

(In the above formula, R ₁ and R ₂ each independently represent a hydrogen atom, a lower alkyl group which may have a substituent, an aryl group or a heterocyclic group, and R ₁ and R ₂
May combine with each other to form a ring. P is the same as in the general formula (4-b). )

[0035]

[Chemical 15] (In the above formula, R ₁ , R ₂ and P are each represented by the general formula (4
-The same as in c). )

[0036]

[Chemical 16] (In the above formula, R ₃ and R ₄ are each independently a hydrogen atom, an alkyl group which may have a substituent, an unsaturated alkyl group which may have a substituent, an aryl group, a hetero group A cyclic group, a vinyl group which may have a substituent, or a butadienyl group which may have a substituent, R ₃
And R ₄ may combine with each other to form a ring. P is the same as in the general formula (4-b). )

[0037]

[Chemical 17] (In the above formula, R ₁ and R ₃ are each represented by the general formula (4-
c) and the same as in the general formula (4-e). )

[0038]

[Chemical 18] (In the above formula, R ₁ and P are each represented by the general formula (4-c).
And (4-b). )

[0039]

[Chemical 19] (In the above formula, R ₅ represents an alkyl group which may have a substituent, an unsaturated alkyl group or an aryl group.)

[0040]

[Chemical 20] (In the formula, V represents a heterocyclic divalent group containing a nitrogen atom in the ring, or an aromatic hydrocarbon divalent group, and these may have a substituent.)

Next, these general formulas (4-a) to (4-
Some specific examples of the substituent in m) are shown below: Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the alkyl group which may have a substituent include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, an n-octyl group and a benzyl group. , P
-Methylbenzyl group, p-chlorobenzyl group, 2-phenylethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, allyl group, 2-hydroxyethyl group, 2-methoxyethyl group, 3-morpholinopropyl group, Examples thereof include a 2-diethylaminoethyl group and a 3-carbazolylmethyl group. Among them, the lower alkyl group usually indicates an alkyl group having 1 to 6 carbon atoms.

As the aryl group, a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, a phenanthryl group,
Aromatic hydrocarbon groups such as anthraquinolyl group, acenaphthyl group, fluorenyl group, biphenylyl group, p-terphenylyl group, p-styrylphenyl group, and the like,
Examples of these substituents include alkyl groups such as methyl group, ethyl group and butyl group; halogen atoms such as fluorine, chlorine, bromine and iodine; alkoxy groups such as methoxy group, ethoxy group and butoxy group; aryloxy groups such as phenoxy group. Group; hydroxy group; nitro group; cyano group; amino group; substituted amino group such as dimethylamino group, diethylamino group, dibenzylamino group; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; aryl such as phenyloxycarbonyl group Roxycarbonyl group; Acyloxy group such as acetoxy group and benzoyloxy group; Acyl group such as acetyl group and benzoyl group; Substituted aminocarbonyl group such as carbamoyl group, dimethylaminocarbonyl group and phenylaminocarbonyl group; benzyloxy group and phenethyloxy group Aryl group Kokishi group, and the like.

Examples of the heterocyclic group include furyl group, thienyl group, thiazolyl group, indolyl group, pyrrolyl group, carbazolyl group, pyridyl group, quinolyl group, imidazolyl group,
Oxazolyl group, triazolyl group, piperidyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, acridyl group, xanthenyl group, phenazinyl group, phenothiazinyl group, coumarinyl group, etc., and the same substituents as aryl group You may have.

Examples of the alkoxy group include a methoxy group and an ethoxy group, and examples of the aryloxy group include a phenoxy group, a p-chlorophenoxy group, a p-methylphenoxy group, a 1-naphthoxy group, and an aralkyloxy group. Examples thereof include a benzyloxy group and a phenethyloxy group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group, and examples of the aryloxycarbonyl group include a phenoxycarbonyl group and a 1-naphthoxycarbonyl group.

Examples of P include a divalent group required to be condensed with a benzene ring to form an aromatic hydrocarbon or a heterocyclic ring such as a naphthalene ring, anthracene ring, carbazole ring, benzocarbazole ring and dibenzofuran ring. R ₁
Examples of the group of R ₂ and R ₂ which are bonded to each other to form a ring include a cyclohexylidene group, an indenylidene group, a fluorenylidene group, a pentamethylene group, and the like. Examples of unsaturated alkyl groups include allyl group, 3-butenyl group, cinnamyl group and the like.

V is a divalent group of monocyclic aromatic hydrocarbon such as o-phenylene group; o-naphthylene group, peri
-Naphthylene group, 1,2-anthraquinonylene group, 9,
A divalent group of a condensed polycyclic aromatic hydrocarbon such as a 10-phenanthrylene group, a 3,4-pyrazolediyl group, 2,
3-pyridinediyl group, 5,5-pyrimidinediyl group,
5-1 such as 6,7-indazolediyl group, 5,6-benzimidazolediyl group, 6,7-quinolinediyl group
Examples thereof include a 0-membered ring nitrogen atom, preferably a heterocyclic divalent group containing 2 or less nitrogen atoms in the ring.

V is preferably an o-phenylene group, an o-naphthylene group, a peri-naphthylene group, a 2,3-pyridinediyl group, a 4,5-pyrimidinediyl group, particularly an o-phenylene group or an o-naphthylene group. As such substituents, methyl group, ethyl group, n-propyl group, i-
Alkyl groups such as propyl group, n-butyl group, i-butyl group, n-hexyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group; hydroxyl group; nitro group; cyano group; amino group; Substituted amino groups such as dimethylamino group, diethylamino group and dibenzylamino group; halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; carbamoyl group; phenoxy group And aryloxy groups such as benzyloxy group; aryloxycarbonyl groups such as phenyloxycarbonyl group. Of these, an alkyl group, an alkoxy group, a nitro group, a halogen atom, a hydroxyl group and a carboxyl group, particularly a methyl group, a methoxy group, a nitro group, a chlorine atom and a hydroxyl group are preferable.

The above general formulas (1) and (4-a) to
Some specific examples of the structural formula of the coupler represented by (4-m) are shown in Tables 1 and 2 below. Of course, the present invention is not limited to these specific examples.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Table 5]

[0054]

[Table 6]

[0055]

[Table 7]

[0056]

[Table 8]

[0057]

[Table 9]

[0058]

[Table 10]

[0059]

[Table 11]

[0060]

[Table 12]

[0061]

[Table 13]

[0062]

[Table 14]

[0063]

[Table 15]

[0064]

[Table 16]

[0065]

[Table 17]

[0066]

[Table 18]

[0067]

[Table 19]

[0068]

[Table 20]

[0069]

[Table 21]

[0070]

[Table 22]

[0071]

[Table 23]

[0072]

[Table 24]

[0073]

[Table 25]

[0074]

[Table 26]

[0075]

[Table 27]

[0076]

[Table 28]

[0077]

[Table 29]

[0078]

[Table 30]

[0079]

[Table 31]

[0080]

[Table 32]

[0081]

[Table 33]

[0082]

[Table 34]

In the azo compound represented by the general formula (3),
D is a divalent group in which the carbon atom to which the azo group is bonded is an SP ² type carbon atom forming a double bond, and specifically, it is 2 of an aromatic hydrocarbon ring or an aromatic heterocycle. A valent group, a group in which these are directly bonded, a group which is condensed to form a condensed ring, or a divalent group bonded by a bonding group, an aromatic hydrocarbon ring, an aliphatic hydrocarbon ring, or a heterocycle Is mentioned.

Examples of the linking group include --O--, --S--,-.
S-S -, - SO - , - SO 2 -, - SO 2 NH -, -
_{CH 2 -, - NH -,} - CO -, - CO-CO -, - C
_{O 2 -, - CONH -,} - CH = CH -, - CH = C
(CN)-, -CH = CH-CH = CH-, -N = N
-, -CH = N-N = CH-, -NH-NH-, -CH
= N-, -CONH-NH-, -NHCONH-, -C
≡C-, -C≡C-C≡C-,

[0085]

[Chemical 21] and so on.

Further, examples of the hydrocarbon ring and the heterocycle include:
Benzene, naphthalene, acenaphthene, anthracene,
Pyrene, fluorene, fluorenone, phenanthrene,
Naphthoquinone, anthraquinone, cyclohexane, cyclohexanone, piperazine, pyrrole, furan, thiophene, oxazole, thiazole, pyrazole, pyrazoline, imidazole, imidazolidine, oxadiazole, thiadiazole, triazole, pyridine, indole, quinoline, carbazole, xanthene, coumarin, xanthone. , Phenothiazine and the like, D
Are obtained by combining these hydrocarbon rings or heterocycles with the above-mentioned bonding groups. These hydrocarbon rings and heterocycles may have a substituent. Some of these concrete examples are shown in the table below.
3 shows.

[0087]

[Table 35]

[0088]

[Table 36]

[0089]

[Table 37]

[0090]

[Table 38]

[0091]

[Table 39]

[0092]

[Table 40]

[0093]

[Table 41]

The azo compound of the present invention can be produced, for example, by the following method. The following general formula (5)

[0095]

[Chemical formula 22]

The tetrazonium salt represented by the formula (1) is reacted with a coupler of the general formula (1) and a coupler which is the same as or different from the coupler of the general formula (1) to give the following general formula (3).

[0097]

[Chemical formula 23]

A method for producing an azo compound represented by: As the reaction solvent, water and / or dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, methanol, ethanol,
An organic solvent such as isopropanol is suitable, and the reaction may be performed in the presence of a base at a temperature of 30 ° C. or lower for about 30 minutes to 10 hours.

The coupler represented by the general formula (1) is
For example, according to the following reaction formula, in the presence of a base, hydroxysalicylaldehyde derivative and cyanomethylene derivative,
Obtained by condensation and ring closure (Dye. Pig
m. , 13 (4) 301-10 (1990)).

[0100]

[Chemical formula 24] (In the formula, Z is the same as the above definition.)

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more azo compounds represented by the general formula (2) or (3). Although various types of photosensitive layers are known, the photosensitive layer of the electrophotographic photosensitive member of the present invention may be any of them. Usually, it is a photosensitive layer of the type illustrated below. Photosensitive layer composed of azo compound Photosensitive layer in which azo compound is dispersed in binder Photosensitive layer in which azo compound is dispersed in well-known carrier transporting material Any one of the above-mentioned photosensitive layers is used as a charge generation layer, and well-known Photosensitive layer laminated with charge transport layer containing carrier transport material

The azo compound represented by the general formula (1) generates a charge carrier with extremely high efficiency when absorbing light. The generated carrier can be moved using an azo compound as a medium, but it is preferable to move the carrier using a well-known charge carrier transporting medium. From this point, particularly preferable is to disperse the azo compound of the present invention as a carrier generating material in a binder to form a charge generating layer,
Function-separated type photoreceptor such as a laminated type photoreceptor in which a well-known carrier transportation material is laminated, and a single layer type photoreceptor in which a well-known carrier transportation material is added to a dispersion layer of the above azo compound. Is mentioned.

The azo compound represented by the above general formula (1) of the present invention has a high charge carrier generation efficiency and a high carrier injection efficiency into the carrier transport material, and is suitable for the above-mentioned laminated type or single layer type function-separated photoreceptor. It has excellent performance as a carrier generating material. The carrier transport materials used in combination with the azo compound of the present invention are generally classified into two kinds, an electron transport material and a hole transport material, but both can be used in the photoconductor of the present invention, or a mixture thereof. Can also be used. As the electron transport material, an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group, an ester group, for example, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, etc. Examples include nitrated fluorenone or tetracyanoquinodimethane. In addition, as a hole transport material, an electron-donating organic photoconductive compound such as carbazole,
Indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole, benzoxazole, benzothiazole,
Heterocyclic compounds such as naphthothiazole, diarylalkane derivatives such as diphenylmethane, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives, diarylethylenes such as stilbene. Examples thereof include derivatives and hydrazone compounds. Particularly, substituted amino groups such as dialkylamino groups and diphenylamino groups, or electron donating groups such as alkoxy groups and alkyl groups, or aromatic compounds substituted with these electron donating groups. A compound having a large electron-donating property in which a group ring group is substituted is included. Further, a polymer having a group composed of the above-mentioned compound in the main chain or side chain, such as polyvinylcarbazole, polyglycidylcarbazole, polyvinylpyrene, polyvinylphenylanthracene, polyvinylacridine, and pyrene-formaldehyde resin can also be mentioned.

The electrophotographic photoreceptor of the present invention is a photoreceptor having a photosensitive layer containing the azo compound of the present invention on a conductive support, and in addition to these, an intermediate such as an adhesive or a blocking layer. Layers such as layers and protective layers may be provided to improve performance such as electrical properties and mechanical properties. As the conductive support, any of those known in electrophotographic photoreceptors can be used. Specifically, for example, a metal drum of aluminum, copper or the like, a sheet, a laminate of these metal foils, or a vapor deposit is used. Further, there may be mentioned plastic films, plastic drums, papers and the like, which have been subjected to a conductive treatment by coating a conductive substance such as metal powder, carbon black, copper iodide, a conductive polymer and a polymer electrolyte with a suitable binder. Also, a conductive plastic sheet or drum containing metal powder, carbon black, carbon fiber, or other conductive substance, or tin oxide,
Examples thereof include a plastic film having a conductive metal oxide layer such as indium oxide on its surface.

The photosensitive layer containing the azo compound of the present invention can be produced by a conventional method. For example, for an electrophotographic photoreceptor having a photosensitive layer of the above-mentioned type, a coating solution obtained by dissolving or dispersing the azo compound represented by the general formula (1) in a suitable medium is coated on a conductive support. It can be produced by drying, and then forming a photosensitive layer having a film thickness of usually several μm to several tens of μm. As a medium for preparing a coating solution, a basic solvent capable of dissolving a bisazo compound such as butylamine or ethylenediamine or an ether such as tetrahydrofuran or 1,4-dioxane; a ketone such as methyl ethyl ketone or cyclohexanone; an aromatic carbonization such as toluene or xylene. Hydrogen; aprotic polar solvent such as N, N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethylsulfoxide;
Examples thereof include alcohols such as methanol, ethanol and isopropanol; esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; media for dispersing azo compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. When a medium in which the azo compound is dispersed is used, the azo compound has a particle size of 5 μm or less, preferably 1
It is necessary to reduce the particle size to less than or equal to μm, and optimally less than or equal to 0.5 μm.

By dissolving the binder resin in the coating liquid used for forming the photosensitive layer of the above type, an electrophotographic photoreceptor having the photosensitive layer of the above type can be manufactured. Examples of the binder resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid ester, methacrylic acid ester, vinyl alcohol, and ethyl vinyl ether, phenoxy resin, polysulfone, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane. , Cellulose ester, cellulose ether, epoxy resin, silicon resin and the like.

The ratio of the azo compound of the present invention to the binder resin is not particularly limited, but in general, the azo compound 1
5 to 500 parts by weight, preferably 20 to 100 parts by weight
~ 300 parts by weight of binder resin are used. In addition to the above, a dispersion stabilizer, a coatability improving agent, and a dye, an electron-withdrawing compound and other additives for improving the performance may be added to the above coating liquid.

Similarly, a single-layer type function-separated type photoreceptor can be manufactured by dissolving a carrier transport material in a coating solution used for forming the above-mentioned type photosensitive layer. As the carrier transport material, any of those exemplified above can be used. It is preferable to use a binder resin other than a carrier transport material such as polyvinyl carbazole and polyglycidyl carbazole which has a film-forming property itself and can be used as a binder.

As the binder resin, any of those exemplified above can be used. In this case, the amount of the binder resin used is usually 10 to 10 relative to 10 parts by weight of the azo compound.
00 parts by weight, preferably 30 to 500 parts by weight, and the carrier transport material is 5 to 1000 parts by weight,
It is preferably in the range of 20 to 500 parts by weight. As such, in the case of a carrier transport material which can be used as a binder, 3 to 100 parts by weight is usually used with respect to 1 part by weight of the azo compound.

In this case, another binder polymer may be added to improve the performance of the photosensitive layer such as adhesiveness and flexibility. The thickness of the single layer type photosensitive layer is usually 5 to 50 μm.
m, preferably 10 to 30 μm. The photosensitive layer containing the azo compound (1) to (4) is used as the charge generating layer, and the charge transporting layer containing the carrier transporting material exemplified above is laminated to obtain a laminated type function-separated photoreceptor. The thickness of the charge generation layer is 0.05 to 5 μm, preferably 0.1.
Set to ~ 2 μm.

Two or more kinds of carrier transport materials may be mixed and used. When the carrier-transporting material is a polymer compound having a film-forming property, the binder resin may not be particularly used, but it may be mixed for improving flexibility. When the carrier transport material is a low molecular weight compound, a binder resin is used for forming a film. As the binder resin, those mentioned above are used, and the amount thereof is usually in the range of 50 to 3000 parts by weight, preferably 70 to 1000 parts by weight, per 100 parts by weight of the carrier transport material.

In addition to the above, various additives can be used in the charge transport layer in order to improve the performance and the mechanical strength and durability of the coating film. Examples of such additives include electron-withdrawing compounds and dyes, stabilizers such as ultraviolet ray attractants and antioxidants, coatability improving agents, plasticizers and cross-linking agents.
Examples of the electron-withdrawing compound include chloranil and 2,3-
Dichloro-1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5-
Quinones such as nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone, aldehydes such as 4-nitrobenzaldehyde, 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 3,3 ', 5,5'- Ketones such as tetranitrobenzophenone, phthalic anhydride, acid anhydrides such as 4-chloronaphthalic anhydride, tetracyanoethylone, terephthalalmalononitrile, 4-nitrobenzalmalononitrile, 4-benzoyloxybenzalmalononitrile, Four
Cyano compounds such as-(p-nitrobenzoyloxy) benzalmalononitrile; 3-benzalphthalide, 3-
(Α-Cyano-p-nitrobenzal) phthalide, 3-
(Α-Cyano-p-nitrobenzal) -4,5,6,7
Phthalides such as tetrachlorophthalide.

The charge generation layer and the charge transport layer may be laminated in either order. However, since the charge generation layer is a thin layer, it is susceptible to mechanical damage. Therefore, the charge transport layer is usually laminated on the charge generation layer. To do. The thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 10 to 40 μm.

[0114]

The electrophotographic photoreceptor containing the azo compound of the present invention has high sensitivity and good color sensitivity, and since light fatigue is small in particular, sensitivity, chargeability and residual potential when repeatedly used. It is a laser printer and a liquid crystal shutter printer that are highly stable and highly durable, and are not only suitable for medium- and high-speed PPCs, but also require stable performance and reliability. The photoconductor is also suitable as a photoconductor for a printer such as an LED printer.

[0115]

EXAMPLES Next, the present invention will be explained more specifically with reference to examples and examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following, "parts" means "parts by weight".

Reference Example 1 2-Benzimidazolylacetonitrile (manufactured by Tokyo Kasei)
To a mixture of 4.72 parts and 75 parts of ethanol was added 0.6 parts of piperidine, and further 4.15 parts of 2,5-dihydroxybenzaldehyde. After stirring at room temperature for 5 hours, the precipitated crystals were filtered and washed to obtain 7.54 parts of yellow-green crystals. Next, 7.54 parts of this crystal was added to 60 parts of dioxane, 15 parts of concentrated hydrochloric acid was added, the temperature was raised, and under heating under reflux, 3.
Stir for 5 hours. After allowing to cool to room temperature, 60 parts of water was added and the precipitated crystals were filtered. The obtained crude crystals were recrystallized from 900 parts of methanol to give a coumarin-based coupler No. A-1; 3.22 parts were obtained as yellow needle crystals (yield 38.6%).

[0117]

[Chemical 25]

Physical property values IR spectrum: Shown in FIG. Mass spectrum: 278 (M ⁺ ), 250, 22
2,193,167,139,90,63,39,18

Production Example 1 Compound (Coupler No. A-1) synthesized in Reference Example 1
0.45 parts and compound (Coupler No. B-16
0) 2,5-bis (p-aminophenyl) -1,3,4-oxadiazole was diazotized while maintaining a solution of 0.46 parts dissolved in 91 parts of dimethyl sulfoxide at a temperature of 18 to 23 ° C. A solution of 0.67 parts of the tetrazonium borohydrofluoride salt obtained in 9 parts in 9 parts of dimethyl sulfoxide was added, and sodium acetate 1.
A solution prepared by dissolving 35 parts in 4 parts of water was added dropwise, and the mixture was stirred as it was for 3 hours. The deposited precipitate was separated by filtration, washed with dimethyl sulfoxide, diluted acetic acid, water, methanol and tetrahydrofuran, and dried to obtain a black crystalline compound represented by the following structural formula and its isomer mixture. The yield was 0.69 parts (54.8%). The infrared absorption spectrum of this azo compound is shown in FIG.

[0120]

[Chemical formula 26]

Example 1 0.4 part of the azo compound synthesized in Production Example 1
Si-4-methylpentanone-2 with 30 parts Sandog
Disperse with a liner, and add polyvinyl butler to it.
Le (Sekisui Chemical Co., Ltd., trademark S-REC BH-3)
Was added and dissolved. Dispersion of the obtained azo compound
The solution was deposited on a 75 μm thick polyester film.
A dry film thickness of 0.
4 g / m ²And then dried. In this way
N-ethylcarbazole-3-on the resulting charge generation layer
Aldehyde diphenylhydrazone 90 parts and polycarbonate
Bonate resin (Mitsubishi Kasei Co., Ltd., trademark Novarex
7025) 100 parts dissolved in 670 parts dioxane
The solution is applied to a dry film thickness of 28 μm and the charge transport layer is applied.
Was formed. In this way, it has a photosensitive layer composed of two layers.
An electrophotographic photoreceptor was obtained.

The half-exposure amount (E _1/2 ) as the sensitivity of these photoconductors was measured by an electrostatic copying paper tester (Model SP-428 manufactured by Kawaguchi Denki Seisakusho) for the photoconductors. First, it was charged by corona discharge at -6.5 kV in a dark place, and then exposed to white light with an illuminance of 5 lux to determine the exposure amount necessary for the surface potential to be attenuated to half the initial surface potential. The half-dose exposure amount (E _1/2 ) thus obtained is 1.
It was 35 lux · sec. The surface potential (residual potential) after sufficiently exposed (after 50 lux · sec exposure) was 9V.

Example 2 In place of the azo compound used in Example 1, a coupler No. 1 was prepared by a method similar to the synthetic method of Production Example 1. A- 3 to 0.90
Except that an azo compound having the following structural formula, which was synthesized by using 1 part, was used to prepare a photoconductor in the same manner as in Example 1 except that a sensitivity E was obtained.
_1/2 was measured. The obtained E _1/2 is 9.69 lux · se
The residual potential was 20V.

[0124]

[Chemical 27]

Example 3 Instead of the azo compound used in Example 1, a coupler No. 1 was prepared by a method similar to the synthetic method of Production Example 1. A-3 and coupler No. The following structural formula synthesized using B-160

[0126]

[Chemical 28]

A photoconductor was prepared in the same manner as in Example 1 except that the azo compound represented by the formula (1) was used, and the sensitivity E _1/2 was measured. The obtained E _1/2 is 2.21 lux · sec,
The residual potential was 36V.

Example 4 Instead of the azo compound used in Example 1, a coupler No. 1 was prepared by a method similar to the synthetic method of Production Example 1. The following structural formula synthesized using A-1

[0129]

[Chemical 29]

A photoconductor was prepared in the same manner as in Example 1 except that the azo compound represented by the formula (1) was used, and the sensitivity E _1/2 was measured. The obtained E _1/2 is 6.25 lux · sec,
The residual potential was 23V.

Examples 5 to 18 Instead of the azo compound used in Examples 1 to 4, the following general formula (5) was used.

[0132]

[Chemical 30]

In, the coupler components A and B are
An azo compound having a structure as a coupler according to Item 6.
A photoconductor was prepared in the same manner as in Example 1 except that
Sensitivity E _1/2Was measured. The measurement results are shown in Table-6.

[0134]

[Table 42]

Examples 19 to 24

[0136]

[Chemical 31]

Other than using the azo compound represented by the general formula (6) and its isomer mixture (D is a divalent group shown in Table 3 ) instead of the azo compound used in Example 1, A photoconductor was prepared in the same manner as in Example 1 and E _1/2 was measured. The results are shown in Table-7.

[0138]

[Table 43]

Examples 25 to 28 In Examples 1, 3, 8, and 12, the composition of the charge transport layer was changed from N-methyl-3-carbazole carbaldehyde diphenylhydrazone 90 instead of 1-pyrenecarbaldehyde diphenylhydrazone. A photoconductor was prepared and the sensitivity was measured in the same manner as in each example except that parts were used. The results are shown in Table- 8 .

[0140]

[Table 44] Table-8 Examples Azo compound in charge generation layer E _1/2 Residual potential (lux · sec) (V) 25 Azo compound of Example 1 2.06 21 26 Azo compound of Example 3.12. 23 27 Azo Compound of Example 8 2.31 24 28 Azo Compound of Example 12 2.420

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum diagram of the compound obtained in Reference Example 1.

FIG. 2 is an infrared absorption spectrum diagram of the azo compound obtained in Production Example 1.

Continuation of the front page (56) Reference JP-A 63-195657 (JP, A) JP-A 8-76392 (JP, A) JP-A 5-323642 (JP, A) JP-A 5-249715 (JP , A) JP-A-3-203741 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 5/06 367 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains an azo compound having a coupler component represented by the following general formula (1). Photoreceptor for photography. [Chemical 1] (In the formula, X represents O or NH, Y represents a hydrogen atom or
A cyano group, Z is may have a substituent, Ben
Zoimidazolyl group, benzoxazolyl group, benzothia
Zolyl group, benzopyrimidone group, naphthopyrimidone group,
Thienyl group, benzothienyl group, benzofuryl group, benzene
Represents a zopyrrolyl group or a pyridyl group, and ring Q may have a substituent , benzene ring, naphthalene ring, pyridyl ring
Gin ring, quinoline ring, indole ring, or thianaphthalate
Indicates a len ring . ) 2. The electrophotographic photoreceptor according to claim 1, wherein the azo compound is an azo compound represented by the following general formula (2). [Chemical 3] (In the formula, Ar represents an aromatic hydrocarbon group, a heterocyclic group or a group in which they are bonded via a bonding group, n represents a number of 1, 2, 3 or 4, X, Y, Z and Q Is the same as the definition in the general formula (1).) 3. The electrophotographic photoreceptor according to claim 1, wherein the azo compound is an azo compound represented by the following general formula (3). [Chemical 4] (In the formula, at least one of the couplers A and B represents the residue of the coupler component represented by the general formula (1), and D is S in which the carbon atom to which the azo group is bonded forms a double bond.
A divalent group which is a P ² -type carbon atom is shown. ) 4. A photosensitive layer containing a carrier-generating material and a carrier-transporting material, wherein the azo compound according to claim 1, 2 or 3 is used as the carrier-generating material. The electrophotographic photoconductor described. 5. The photosensitive layer has at least a charge generating layer containing a carrier generating material, and a charge transporting layer containing a carrier transporting material and a binder resin, wherein the charge generating layer contains a carrier generating material. The azo compound according to claim 2 or 3 is used, and the azo compound according to claim 1 or 2,
Alternatively, the electrophotographic photoreceptor according to item 4. 6. The electrophotographic photoreceptor according to claim 5, wherein the charge generation layer contains a carrier generation material and a binder resin.