JPH0950139A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor having high sensitivity, less liable to optical fatigue and excellent in durability. SOLUTION: This electrophotographic photoreceptor contains an azo compd. having a coupler component represented by the formula in the photosensitive layer. In the formula, Q is a divalent arom. hydrocarbon group or a divalent heterocyclic group and R is H, alkyl, alkenyl, aryl or cycloalkyl.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an electrophotographic photosensitive member. 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 for 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.

Presently mainly put into practical use are photoreceptors of a function-separated type in which the functions of generating and transporting charge carriers are separated and shared by different compounds. The function-separated type photoreceptor is capable of combining a compound having a high generation efficiency of charge carriers and a compound having a high transportation efficiency,
Further, it is a type in which a wide selection of materials having excellent durability is possible, and a photosensitive member having high sensitivity and excellent durability 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 An object of the present invention is to provide an 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 using specific couplers are preferred. The inventors have found that and reached the present invention. That is, the gist of the present invention is 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). Exists in a photoconductor for electrophotography.

[0009]

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(In the formula, Q represents a divalent group of an aromatic hydrocarbon which may have a substituent or a divalent group of a heterocyclic ring which may have a substituent. R represents hydrogen. An atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted aryl group, or an optionally substituted cycloalkyl group is shown.) Preferably, the following general formula ( The electrophotographic photoreceptor according to claim 1, which is an azo compound represented by 2).

[0011]

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(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 1, 2, 3 or 4. ) More preferably, the electrophotographic photoreceptor according to claim 1, which is an azo compound represented by the following general formula (3).

[0013]

Embedded image A−N = N−D−N = N−B (3)

(In the formula, at least one of 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.)

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The azo compound of the present invention will be described in detail. As the coupler component of the general formulas (1), (2) and (3), Q may have a substituent. It represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring which may have a substituent. 2 of aromatic hydrocarbons
Examples of the valent group include a divalent group of a monocyclic aromatic hydrocarbon such as an o-phenylene group, an o-naphthylene group, and 1,8-
Naphthylene group, 1,2-anthraquinonylene group, 9,1
Examples thereof include divalent groups of condensed polycyclic aromatic hydrocarbons such as 0-phenanthrylene group. Further, the divalent group of the heterocycle includes, for example, 3,4-pyrazolediyl group, 2,3
-Pyridinediyl group, 3,4-pyridinediyl group, 4,
Heterocyclic divalent groups such as a 5-pyrimidinediyl group, a 6,7-indazolediyl group, a 5,6-benzimidazolediyl group and a 5,6-quinolinediyl group can be exemplified.

In the present invention, both Q, that is, the aromatic hydrocarbon divalent group and the heterocyclic divalent group may have a substituent. Examples of such substituents include methyl group, ethyl group, n-propyl group, i-propyl group, n
An alkyl group such as a butyl group, an i-butyl group, an n-hexyl group; a substituted alkyl group such as a trifluoromethyl group; an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group; a hydroxyl group; a nitro group; Cyano group; amino group; substituted amino group such as dimethylamino group, diethylamino group, dibenzylamino group; fluorine atom, chlorine atom,
Halogen atom such as bromine atom and iodine atom; Carboxyl group; Alkoxycarbonyl group such as ethoxycarbonyl group; Carbamoyl group; Acyl group such as acetyl group and benzoyl group; Aryloxy group such as phenoxy group; Arylalkoxy group such as benzyloxy group An aryloxycarbonyl group such as a phenyloxycarbonyl group and the like.
Among them, an alkyl group, an alkoxy group, a nitro group, a halogen atom, a hydroxyl group, and a carbamoyl group, particularly, a methyl group, a methoxy group, a nitro group, a chlorine atom, and a hydroxyl group are preferred.

R is a hydrogen atom; an alkyl group which may have a substituent, specifically, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, t
ert-butyl group, n-hexyl group, n-octyl group,
Benzyl group, p-methylbenzyl group, p-chlorobenzyl group, 2-phenylethyl group, 1-naphthylmethyl group,
2-naphthylmethyl group, 2-hydroxyethyl group, 2-
Methoxyethyl group, 3-morpholinopropyl group, 2-diethylaminoethyl group, 3-carbazolylmethyl group and the like can be mentioned, and aryl group, specifically, phenyl group, naphthyl group, anthryl group, pyrenyl group, phenanthryl group. , Anthraquinolyl group, acenaphthyl group, fluorenyl group, biphenylyl group, p-terphenylyl group, p-styrylphenyl group, and other aromatic hydrocarbon groups. These substituents include methyl group, ethyl group, butyl group. An alkyl group such as: a halogen atom such as fluorine, chlorine, bromine, iodine; an alkoxy group such as a methoxy group, an ethoxy group, a butoxy group; an aryloxy group such as a phenoxy 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; aryloxycarbonyl group such as phenyloxycarbonyl group 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, phenethyloxy group etc. Arylalkoxy groups and the like, and the alkenyl group which may have a substituent specifically includes an allyl group, a methylallyl group, a bromoallyl group, a chloroallyl group and the like, which has a substituent. As a cycloalkyl group , Specifically, a cyclohexyl group, a cycloheptyl group, methylcyclohexyl group, bromo cyclohexyl, hydroxycyclohexyl group and the like. Among them, R is a hydrogen atom and has 1 carbon atom.
Alkyl groups and allyl groups of 4 to 4 are preferable. In the general formula (2), Ar represents an aromatic hydrocarbon group or a heterocyclic group which may be bonded via a monovalent to tetravalent bonding group.

The aromatic hydrocarbon group is, for example, a monovalent or condensed polycyclic aromatic hydrocarbon monovalent group such as a phenyl group, a naphthyl group, a 1-pyrenyl group, a 2-anthryl group, a 5-acenaphthenyl group. 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; and other divalent groups such as biphenylene group. The aromatic hydrocarbon group bonded through a bonding group has the general formula

[0019]

[Chemical 7]

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 diphenylaminostilbene-tetrayl group may be mentioned.

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

[0022]

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Bisphenylene group and naphtholinebenzimidazolyl group represented by:

[0024]

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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, bromine atom; alkyl group such as methyl group, ethyl group, n-propyl group, 1-butyl group; methoxy group, ethoxy group, propoxy group, etc. Alkoxy group; aryl group such as phenyl group; arylamino group such as phenylamino group; aryloxy group such as phenoxy group; styryl group,
Examples thereof include aryl vinyl groups such as naphthyl vinyl group. 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 by a coupling reaction of a diazonium salt, B represents a residue of a coupler having a phenolic hydroxyl group which is the same as or different from A, and is represented by a diazonium salt. Any coupler can be used for the coupling reaction.

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

[0028]

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

[0030]

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(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 Z represents a divalent group required for being condensed with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle.)

[0032]

[Chemical 12]

(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. Z is the same as in the general formula (4-b). )

[0034]

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(In the above formula, R ₁ , R ₂ and Z are the same as in the above general formula (4-c).)

[0036]

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(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, or an aryl group. Group, a heterocyclic 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. Z is the same as in the general formula (4-b). )

[0038]

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(In the above formula, R ₁ and R ₃ are the same as those in the above general formula (4-c) and general formula (4-e).)

[0040]

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(In the above formula, R ₁ and Z are the same as those in the above general formulas (3-c) and (3-b).)

[0042]

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

[0044]

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(In the above formula, R ₆ , R ₇ , R ₈ and R
₉ each independently represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, a vinyl group which may have a substituent, a substituted amino group or an aryl group, and R ₆ represents In addition, it represents a heterocycle. )

[0046]

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(In the formula, V represents a divalent group of a heterocycle containing a nitrogen atom in the ring, or a divalent table of an aromatic hydrocarbon,
These may have a substituent. ) Next, some specific examples of the substituents in these general formulas (4-a) to (4-m) are shown; 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,
Examples thereof include a 3-morpholinopropyl group, a 2-diethylaminoethyl group, a 3-carbazolylmethyl group, and among these, the lower alkyl group usually indicates an alkyl group having 1 to 6 carbon atoms.

Examples of the aryl group include 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,
Examples include oxazolyl group, triazolyl group, piperidyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, acridyl group, xanthenyl group, phenazinyl group, phenothiazinyl group, coumarinyl group, etc. 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 and 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 Z 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 groups 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 and a pentamethylene group. Examples of the unsaturated alkyl group include an allyl group, a 3-butenyl group, a cinnamyl group, and the like.

As V, 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 nitrogen atom, preferably a heterocyclic divalent group containing 2 or less nitrogen atoms in the ring.

Of these, o-phenylene group, o-naphthylene group, peri-naphthylene group, 2,3-pyridinediyl group, 4,5-pyrimidinediyl group, especially o-phenylene group and o-naphthylene group are preferable, Examples of such a substituent include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group and an n-hexyl group; a methoxy group, an ethoxy group, a propoxy group, Alkoxy group such as butoxy group; hydroxyl group;
Nitro group; cyano group; amino group; substituted amino group such as dimethylamino group, diethylamino group, dibenzylamino group; halogen atom such as fluorine atom, chlorine atom, bromine atom, iodine atom; carboxyl group; ethoxycarbonyl group etc. Examples thereof include an alkoxycarbonyl group; a carbamoyl group; an aryloxy group such as a phenoxy group; an arylalkoxy group such as a benzyloxy group; and an aryloxycarbonyl group such as a phenyloxycarbonyl group. Among them, 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 preferred.

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 only these specific examples.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

[Table 5]

[0060]

[Table 6]

[0061]

[Table 7]

[0062]

[Table 8]

[0063]

[Table 9]

[0064]

[Table 10]

[0065]

[Table 11]

[0066]

[Table 12]

[0067]

[Table 13]

[0068]

[Table 14]

[0069]

[Table 15]

[0070]

[Table 16]

[0071]

[Table 17]

[0072]

[Table 18]

[0073]

[Table 19]

[0074]

[Table 20]

[0075]

[Table 21]

[0076]

[Table 22]

[0077]

[Table 23]

[0078]

[Table 24]

[0079]

[Table 25]

[0080]

[Table 26]

[0081]

[Table 27]

[0082]

[Table 28]

[0083]

[Table 29]

[0084]

[Table 30]

[0085]

[Table 31]

[0086]

[Table 32]

[0087]

[Table 33]

[0088]

[Table 34]

D in the general formula (1) 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, an aromatic group A divalent group of a hydrocarbon ring or an aromatic heterocycle, a group in which these are directly bonded, a group which is condensed to form a condensed ring, a bonding group, an aromatic hydrocarbon ring, an aliphatic hydrocarbon ring, A divalent group bonded by a heterocycle or the like can be mentioned. As typical examples, the divalent group of the aromatic hydrocarbon ring is benzene, naphthalene, anthracene, pyrene, fluorenone, anthraquinone, phenanthrene,
Examples of the divalent group derived from biphenylene, triphenylene, perylene, etc. include divalent groups of an aromatic heterocycle derived from N-ethylcarbazole, acridine, xanthone, phenazine, dibenzothiophene, dibenzofuran, etc. Valuable groups can be mentioned.

Further, some of the specific examples of the divalent groups derived from those in which the divalent groups of these aromatic hydrocarbon rings or aromatic heterocycles are directly bonded or which form a condensed ring are shown in the following table. -3,4.

[0091]

[Table 35]

[0092]

[Table 36]

[0093]

[Table 37]

[0094]

[Table 38]

[0095]

[Table 39]

[0096]

[Table 40]

Examples of the bonding group include --O--, --S--,-.
S-S -, - SO - , - SO 2 -, - SO 2 NH -, -
_{CH 2 -, - NH -,} - CO -, - CO-CO -, - C
_{O 2 -, - COHN -,} - 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-, -CH = CH-CO-C
H = CH- and the like.

Examples of hydrocarbon rings and heterocycles are:
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.
It is shown in FIG.

[0099]

[Table 41]

[0100]

[Table 42]

The method for producing the azo compound of the present invention is not particularly limited, and known methods can be used, for example, the general formula (3)
The azo compound represented by can be produced by the following method. The following general formula (9)

[0102]

Embedded image

The tetrazonium salt represented by the formula (1) is reacted with the coupler of the general formula (1) or the same or different coupler to obtain the following general formula (3).

[0104]

Embedded image A−N = N−D−N = N−B (3)

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, it can be obtained by condensing a derivative of dihydroxynaphthalic anhydride and a derivative of O-phenylenediamine according to the following reaction formula.

[0107]

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The coupler obtained by the above synthetic method can be obtained as a mixture of isomers of the general formulas (1-a) and (1-b), but in the present invention, any isomer can be used, and usually, the reaction is carried out. The isomers produced in Step 1 above are not separated and used as a mixture in the coupling reaction.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more azo compounds having the coupler component represented by the general formula (1). 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 transport material The above-mentioned photosensitive layers are used as charge generation layers, and well-known carrier transport material Photosensitive layer in which a charge transport layer containing

The azo compound having the coupler component 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 of view, particularly preferable is a laminated type photoreceptor in which a charge-transporting layer is laminated by dispersing the azo compound of the present invention as a carrier-generating material in a binder to form a charge-generating layer and a well-known carrier-transporting material. A function-separated type photoconductor such as a single-layer type photoconductor in which a well-known carrier transport material is added to a dispersion layer of an azo compound can be mentioned.

The azo compound having the specific coupler component of the present invention has a high charge carrier generation efficiency and a high carrier injection efficiency into the charge carrier transport material, and thus carrier generation of the above-mentioned laminated or single layer type function-separated photoreceptor. It has excellent performance as a material. The carrier transport materials used in combination with the azo compound of the present invention are generally classified into two types, an electron transport material and a hole transport material, but both can be used in the photoreceptor of the present invention.
Moreover, the mixture 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. As a hole transport material, an electron-donating organic photoconductive compound such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole, benzoxazole, benzothiazole, or naphthothiazole Ring compounds, diarylalkane derivatives such as diphenylmethane, triarylalkane derivatives such as triphenylmethane, triarylamine derivatives such as triphenylamine, phenylenediamine derivatives, N-phenylcarbazole derivatives,
Diarylethylene derivatives such as stilbene, hydrazone compounds, and the like, particularly dialkylamino group,
Examples include compounds having a large electron-donating property, in which a substituted amino group such as a diphenylamino group, an electron-donating group such as an alkoxy group or an alkyl group, or an aromatic ring group substituted with these electron-donating groups is substituted. . Further, a polymer having a group composed of the above-mentioned compound in the main chain or side chain, such as polyvinyl carbazole, polyglycidyl carbazole, polyvinyl pyrene, polyvinyl phenylene anthracene, polyvinyl acridine, and pyrene-formaldehyde resin can also be mentioned.

The electrophotographic photoconductor of the present invention is a photoconductor 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. Specific examples include metal drums and sheets of aluminum, copper, and the like, and laminates and vapor-deposits of these metal foils. 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, an electrophotographic photoreceptor having a photosensitive layer of the type described above has a coating solution obtained by dissolving or dispersing the azo compound represented by the general formula (2) or (3) in an appropriate medium to provide a conductive support. It can be manufactured by coating on a body and drying to form a photosensitive layer having a film thickness of usually several μm to several + 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; N, N
-Aprotic polar solvents such as dimethylformamide, acetonitrile, N-methylpyrrolidone and dimethylsulfoxide; alcohols such as methanol, ethanol and isopropanol; esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; dichloroethane, chloroform and the like. Examples include media in which an azo compound such as chlorinated hydrocarbon is dispersed. When a medium in which the azo compound is dispersed is used, it is necessary to atomize the azo compound to a particle size of 5 μm or less, preferably 1 μm or less, and most preferably 0.5 μm or less.

By dissolving the binder resin in the coating liquid used for forming the photosensitive layer of the above type, the electrophotographic photoreceptor having the photosensitive layer of the above type can be produced. As the binder resin, 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 coating property improving agent, and a dye, an electron-withdrawing compound, and other additives for improving performance may be added to the coating solution.

Similarly, if the carrier transport material is dissolved in the coating liquid used for forming the photosensitive layer of the above-mentioned type, a single layer type function-separated type photosensitive material can be manufactured. 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 to 5 μm.
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 these, 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 absorbers and antioxidants, coatability improvers, plasticizers, and crosslinking agents.
Examples of the electron-withdrawing compound include chloranil, 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, tetracyanoethylene, 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
And phthalides such as tetrachlorophthalide.

The order of stacking the charge generation layer and the charge transport layer may be either. However, since the charge generation layer is a thin layer, it is susceptible to mechanical damage. Therefore, the charge transport layer is usually stacked 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.

[0122]

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.

[0123]

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 10.2 g of 3-hydroxynaphthalic anhydride was dissolved in 120 ml of nitrobenzene and 24 ml of acetic acid, 5.1 g of o-phenylenediamine was added, and the temperature was raised to 135 ° C.
After heating and refluxing at the same temperature for 4 hours, the temperature was lowered to room temperature, and the solid matter that separated out was collected by filtration. The solid was suspended in 160 ml of methanol and dried under reduced pressure to obtain 11.1 g of yellow crystals represented by the following structural formula.

[0125]

Embedded image

The infrared absorption spectrum of this coupler (No. A-1) is shown in FIG. Reference Example 2 7.56 g of the compound synthesized in Reference Example 1 was dissolved in 330 ml of N, N-dimethylformamide, and potassium carbonate 2 was added.
4.19 g was added. 2.39 g of tosyl chloride at 80 ° C
Was added, and after stirring for 30 minutes, the same amount of tosyl chloride was added again. After stirring for 2 hours and a half at the same temperature, the mixture was filtered while hot, the insoluble matter was removed, the filtrate was concentrated, and water was added to crystallize. After hot toluene suspension washing, the product was reprecipitated again with N, N-dimethylformamide-water and dried under reduced pressure to obtain 3.58 g of monotosyl compound as yellow crystals.

Monotosyl body 2.
79 g was dissolved in 56 ml of N, N-dimethylformamide, and 2.53 g of potassium carbonate and 2.66 g of methyl iodide were added at room temperature. After stirring for 1 hour, the mixture was reacted at 40 ° C. for 2 hours and filtered while hot. After washing the residue with water to remove salt,
The precipitate was reprecipitated with N, N-dimethylformamide-water together with the filtrate, and dried under reduced pressure to obtain 2.54 g of methoxy-tosyl compound as yellow crystals.

The total amount obtained was suspended in 97 ml of ethanol, and 5.45 g of potassium hydroxide was added to 97 ml of water while heating under reflux.
The solution dissolved in 1 was added in quarter volume at 15 minute intervals.
After heating and refluxing for another two and a half hours, the mixture was allowed to cool to room temperature and neutralized with acetic acid. The separated solid was filtered, washed with methanol and with toluene, and dried under reduced pressure to obtain 1.28 g of yellow crystals represented by the following structural formula.

[0129]

Embedded image

Production Example 1 Compound (Coupler No. A-1) synthesized in Reference Example 1
0.65 parts and naphthol derivative (Coupler No. B
-12) and 0.57 part of dimethyl sulfoxide 122
While keeping the solution dissolved in the part at a temperature of 18 to 23 ° C,
A solution obtained by dissolving 0.90 parts of tetrazonium borohydrofluoride obtained by diazotizing 2,5-bis (p-aminophenyl) -1,3,4-oxadiazole in 12 parts of dimethyl sulfoxide was prepared. After the addition, a solution prepared by dissolving 1.80 parts of sodium acetate in 5.4 parts of water was added dropwise with stirring, and the mixture was stirred for 3 hours as it was. The deposited precipitate is filtered off,
The crystals were washed with dimethylsulfoxide, diluted acetic acid, water and tetrahydrofuran, and dried to obtain a black crystalline compound represented by the structural formula below and a isomer mixture thereof. Yield is 0.9
It was 2 parts (54.8%). The infrared absorption spectrum of this asymmetric azo compound is shown in FIG.

[0131]

Embedded image

Production Example 2 Instead of the compound (Coupler No. A-1) used in Production Example 1, the compound (Coupler No. A-1) synthesized in Reference Example 2 was used.
-2) was used in the same manner as in Production Example 1 to obtain a dark brown crystal represented by the following structural formula. The yield was 0.39 part (yield 22.6%).

[0133]

[Chemical formula 26]

Example 1 0.4 part of the azo compound synthesized in Preparation Example 1 was mixed with 4 parts of 30 parts.
Sandog with -methoxy-4-methylpentanone-2
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.
4g / m ²And then dried. In this way
N-ethylcarbazole-3-on the resulting charge generation layer
Aldehyde diphenylhydrazone 90 parts and polycarbonate
Bonate resin (trademark Novarex, manufactured by Mitsubishi Chemical Corporation)
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 test device (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 with white light having an illuminance of 5 lux, and the exposure amount necessary for the surface potential to attenuate to half of the initial surface potential was determined. The half-dose exposure amount (E _1/2 ) thus obtained is 1.
It was 01 lux · sec. Further, the surface potential (residual potential) after sufficient exposure (after 50 lux · sec exposure) was −6V.

Example 2 The azo compound synthesized in Preparation Example 2 was used in place of the azo compound used in Example 1, and 1-pyrenecarbaldehydediphenylhydrazone was used instead of 1-pyrenecarbaldehydediphenylhydrazone as the composition of the charge transport layer.

[0137]

Embedded image

A photoreceptor was prepared in the same manner as in Example 1 except that 90 parts of the compound represented by
_1/2 was measured. The obtained E _1/2 is 2.58 lux · s
ec, and the residual potential was -22V.

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. The following structural formula synthesized using A-1

[0140]

Embedded image

A photosensitive member was prepared in the same manner as in Example 1 except that the symmetric azo compound represented by the formula (1) was used, and the sensitivity E _1/2 was measured. The determined E _1/2 was 1.66 lux · sec and the residual potential was −7V.

Examples 4 to 14 Instead of the azo compound used in Examples 1 to 3, the following general formula (10) was used.

[0143]

[Chemical 29]

In the above, except that an azo compound having a structure in which the coupler component A is a coupler described in Table 1 as shown in Table 6 and the coupler component B is a coupler described in Table 2 is used. A photoconductor was prepared in the same manner as in Example 2, and the sensitivity E _1/2 was measured. Table 6 shows the measurement results.

[0145]

[Table 43]

Examples 18 to 23

[0147]

Embedded image

Other than using the azo compound represented by the general formula (11) and its isomer mixture (D is a divalent group shown in Table 4) 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.

[0149]

[Table 44]

[0150]

[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.

Claims (6)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, wherein the photosensitive layer has the following general formula (1):
An electrophotographic photoreceptor comprising an azo compound having a coupler component represented by: Embedded image (In the formula, Q is a divalent group of an aromatic hydrocarbon which may have a substituent or 2 of a heterocyclic ring which may have a substituent.
Shows a valence group. R represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted aryl group, or an optionally substituted cycloalkyl group. ) 2. The azo compound is an azo compound represented by the following general formula (2), wherein:
The electrophotographic photoconductor described. Embedded image (In the formula, Ar represents an aromatic hydrocarbon group, a heterocyclic group or a group in which they are bonded via a bonding group, and n is 1, 2,
Represents 3 or 4. ) 3. The electrophotographic photoreceptor according to claim 1, wherein the azo compound is an azo compound represented by the following general formula (3). Embedded image A−N = N−D−N = N−B (3) (wherein at least one of the couplers A and B represents a 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 bound 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 photoreceptor according to any one of 2 and 3. 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. The carrier generating material in the charge generating layer as claimed in claim 1, The electrophotographic photoconductor according to claim 1, wherein the azo compound according to claim 2 or 3 is used. 6. The electrophotographic photoreceptor according to claim 5, wherein the charge generation layer contains a carrier generation material and a binder resin.