JPH07152174A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain an org. electrophotographic photoreceptor having high stability especially to NOx and high sensitivity and excellent in durability. CONSTITUTION:An amidine compd. represented by the general formula (where each of R<1> and R<2> is H, halogen, alkyl, alkoxy, aryl or aralkyl) is added to a photosensitive-layer on an electric conductive substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used in an image forming apparatus utilizing an electrophotographic method such as an electrostatic copying machine and a laser beam printer.

[0002]

2. Description of the Related Art Electrophotographic methods such as the Carlson process are
The step of uniformly charging the surface of the electrophotographic photosensitive member by corona discharge, the exposure step of exposing the charged surface of the electrophotographic photosensitive member to form an electrostatic latent image on the surface, and the formed electrostatic A developing step of bringing a developer into contact with the latent image and developing the electrostatic latent image into a toner image by the toner contained in the developer, a transfer step of transferring the toner image to paper, etc. After the fixing process of fixing the toner image and the transfer process,
And a cleaning step for removing the toner remaining on the photoconductor.

Recently, the electrophotographic photosensitive member used in the above-mentioned electrophotographic method is replaced with a main component containing an inorganic photoconductor such as selenium or cadmium sulfide, which is difficult to handle due to toxicity. Various so-called organic photoconductors using organic photoconductive compounds with low toxicity have been proposed. Such an organic photoreceptor has the advantages that it has good workability, is easy to manufacture, and has a high degree of freedom in functional design.

As such an organic photoreceptor, generally,
A material having a photosensitive layer of a function separation type in which a charge generating material that generates an electric charge by light irradiation and a charge transporting material that transfers the generated electric charge are dispersed in a binder resin is often used. As the charge generating material forming the function-separated photosensitive layer, many compounds such as azo pigments, perylene pigments, squarylium salt pigments, and polycyclic quinone pigments have been proposed.

As the charge transport material, various organic compounds such as carbazole compounds, oxadiazole compounds, pyrazoline compounds, hydrazone compounds, stilbene compounds, phenylenediamine compounds and benzidine compounds are known. ing. Further, a stabilizer such as an antioxidant or a light stabilizer is added to the photosensitive layer so that the photosensitive layer will not be fatigued and the charging characteristics and the photosensitive characteristics will not be deteriorated. As a stabilizer, not only is it excellent in stabilizing function, but it is also required to have performance such as not adversely affecting the sensitivity characteristics of the photoreceptor, and various stabilizers have been proposed to achieve it. Has been done. Examples of antioxidants include hindered phenols, paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds and the like.

[0006]

However, even though the conventional organic photoconductor contains the above-mentioned stabilizer, the charging property, the photosensitivity, etc. are deteriorated during repeated use. However, there is a problem that sensitivity and durability are deteriorated. That is, in the organic photoreceptor, the charge generation material and the charge transport material are deteriorated by nitrogen oxides (NOx) and ozone (O ₃ ) generated in the image forming process such as charging, exposure, and charge removal as described above during image formation. Alternatively, it decomposes to cause a decrease in sensitivity due to a decrease in charging property, an increase in residual potential, and the like.

The present invention has been made in view of the above circumstances, and has a particularly high stability to nitrogen oxides,
It is an object of the present invention to provide an organic electrophotographic photoreceptor having high sensitivity and excellent durability.

[0008]

In order to solve the above-mentioned problems, an electrophotographic photoreceptor of the present invention comprises a charge-generating material and a charge-transporting material, and a general formula (1) on a conductive substrate.
:

[0009]

[Chemical 2]

[Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group. ] It has the photosensitive layer containing the amidine type compound represented by these, It is characterized by the above-mentioned. In the electrophotographic photoreceptor of the present invention having the above structure, the amidine compound represented by the general formula (1) added to the photosensitive layer is competitive with the charge generating material and the charge transporting material. Reacts with nitrogen oxides to suppress deterioration and decomposition of charge generation materials and charge transport materials due to nitrogen oxides.

The present invention will be described below. The above general formula (1)
In the amidine compound represented by, the halogen atom corresponding to the groups R ¹ and R ² is, for example, a fluorine atom,
A chlorine atom, a bromine atom, an iodine atom and the like are preferred. The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group and a pentyl group. It is given as a thing.

As the alkoxy group, for example, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group and the like having 1 to 5 carbon atoms. Alkoxy groups are mentioned as preferred. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group,
Biphenylyl group, naphthyl group, anthryl group, phenanthryl group and the like are mentioned as preferable ones.

Further, as the aralkyl group, for example, benzyl group, α-phenethyl group, β-phenethyl group, 3-
Phenylpropyl group, benzhydryl group, trityl group and the like are preferred. Further, each group such as the above alkyl group may be substituted with, for example, an amino group, the above halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group or the like as a substituent.

The amidine compound can be synthesized by a conventionally known method. Specific examples of the amidine-based compound include, but are not limited to, compounds of Compound Nos. 1 to 17 in which the groups R ¹ and R ² in the formula are combinations of groups shown in Tables 1 to 3 below. A compound is illustrated.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

Among the above-exemplified compounds, the group R ¹
A compound having a donor group such as a phenyl group has high reactivity with nitrogen oxides, and has an excellent effect of suppressing deterioration and decomposition of the charge generation material and the charge transport material due to the nitrogen oxides. A compound in which the group R ¹ is a donor group such as a phenyl group is probably the following general formula (2) containing this group R ¹ :

[0019]

[Chemical 3]

Since the structural portion of (3) is likely to be nitrated or nitrosated by nitrogen oxide, it is presumed that it has high reactivity with nitrogen oxide. The electrophotographic photoreceptor of the present invention comprises a photosensitive layer containing one or more of the above-mentioned amidine compounds. The photosensitive layer includes (a) a single-layer type photosensitive layer in which a charge generating material and a charge transporting material are dispersed in a binder resin, (b) a charge generating layer containing at least a charge generating material, and a binder resin in the binder resin. There are two types: a laminated photosensitive layer in which a charge transport layer in which a charge transport material is dispersed is laminated,
The present invention can be applied to any of these.

In the case of a laminated type photosensitive layer, the charge generation layer comprises:
There are a resin type in which a charge generating material is dispersed in a binder resin and a vapor deposition type in which a charge generating material is formed into a film by a method such as vapor deposition.The amidine compound is the former resin type charge generating material. It can be added only to the layer. The amidine compound can also be added to the charge transport layer. That is, in the laminated photosensitive layer, in the photosensitive layer in which the resin type charge generation layer and the charge transport layer are combined, the amidine compound is
It can be added to either or both of the charge generation layer and the charge transport layer. Further, in the photosensitive layer in which the vapor deposition type charge generation layer and the charge transport layer are combined, the amidine compound can be added only to the charge transport layer.

The addition amount of the amidine-based compound is not particularly limited in the present invention, and an optimum amount may be added depending on the compatibility with the binder resin constituting the photosensitive layer, and the like. In the case of a layer, it is preferable to add the amidine compound in a proportion of 0.05 to 10.0 parts by weight, and in a proportion of 0.1 to 5.0 parts by weight, relative to 100 parts by weight of the binder resin. More preferably.

When an amidine compound is added to the resin type charge generating layer of the laminated type photosensitive layer, the binder resin 10 is used.
The amidine compound is used in an amount of 0.05-2 with respect to 0 part by weight.
It is preferably added in a proportion of 0.0 parts by weight,
More preferably, it is added in a proportion of 10.0 parts by weight. Furthermore, when the amidine compound is added to the charge transport layer of the laminated photosensitive layer, it is preferable to add the amidine compound at a ratio of 0.05 to 20.0 parts by weight to 100 parts by weight of the binder resin. It is more preferable to add it in a ratio of 0.1 to 10.0 parts by weight.

In any case, if the addition amount of the amidine compound is less than the above range, the effect of the addition cannot be sufficiently obtained, and the electrophotographic photoreceptor may not be stabilized. On the contrary, when the amount of the amidine compound added exceeds the above range, the stability of the photoconductor may be deteriorated. In order to obtain a single-layer type photosensitive layer, an amidine compound is dissolved or dispersed in a suitable solvent together with a charge generating material, a charge transporting material, a binder resin, etc., and a coating solution is applied onto a conductive substrate by a method such as coating. It may be applied directly to or through another layer and dried.

In order to obtain a laminated type photosensitive layer having a vapor deposition type charge generation layer, first, a charge generation layer is formed by vapor deposition on a conductive substrate directly or through another layer, Then, on this charge generation layer, an amidine compound,
A coating liquid containing a charge transport material and a binder resin may be applied by a method such as coating and dried to form a charge transport layer. On the contrary to the above, it is also possible to first form the charge transport layer on the conductive substrate and then form the charge generation layer thereon by vapor deposition.

Further, in order to obtain a laminated type photosensitive layer having a resin type charge generation layer, first, a charge generation material and a binder resin, directly or through another layer, on a conductive substrate, If necessary, a coating solution containing an amidine compound is applied by a method such as coating and dried to form a charge generation layer, and then a charge transport material and a binder resin are required on the charge generation layer. A coating solution containing an amidine compound is applied by a method such as coating and dried to form the charge transport layer. In contrast to the above, it is also possible to first form the charge transport layer on the conductive substrate and then form the charge generation layer by coating on the charge transport layer.

The charge generating material is not limited to these, but for example, inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, α-silicon, azo pigments, perylene pigments. , Squarylium salt pigments, polycyclic quinone pigments, phthalocyanine pigments, indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, dithioketopyrrolopyrrole pigments and the like. These charge-generating materials may be used alone or in combination of two or more, depending on the sensitivity region of the electrophotographic photosensitive member. When forming a resin type charge generation layer, the inorganic photoconductive material is made into a powder form and dispersed in the binder resin.

Among the above charge generating materials, a positively chargeable electrophotographic photoreceptor containing an n-type pigment such as an azo pigment, a perylene pigment, a squarylium salt pigment and a polycyclic quinone pigment is charged and exposed. Since a large amount of nitrogen oxide is generated in the image forming process such as static elimination, it is desirable to improve the resistance to nitrogen oxide by the constitution of the present invention.

As the azo pigments, various azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments and polyazo pigments can be used, and bisazo pigments are particularly preferably used. Examples of the bisazo pigment include compounds represented by the following general formulas (a1) to (a15).

[0030]

[Chemical 4]

[0031]

[Chemical 5]

[In the formula, R ⁵⁰ represents an alkyl group or an aryl group which may have a substituent, and Y ¹ and Y
² is the same or different and represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or an alkoxy group, and A represents a coupler residue. ]

[0033]

[Chemical 6]

[In the formula, Y ¹ , Y ² and Y ³ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or an alkoxy group, and A is the same as defined above. ]

[0035]

[Chemical 7]

[In the formula, R ⁵¹ hydrogen atom, halogen atom,
Represents an alkyl group or a cyano group which may have a substituent, D represents an oxygen atom, a sulfur atom or an imino group,
l represents an integer of 0 or 1, and A is the same as above. ]

[0037]

[Chemical 8]

[In the formula, Y ¹ and Y ² are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group which may have a substituent, and A is the same as defined above. ]

[0039]

[Chemical 9]

[In the formula, R ⁵² represents an alkyl group which may have a hydrogen substituent, an aryl group which may have a substituent or a heterocyclic group, and l and A are the same as the above]

[0041]

[Chemical 10]

[In the formula, R ⁵³ and R ⁵⁴ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group which may have a substituent, an aryl group or an alkoxy group, and D and A are the above-mentioned. Is the same as. ]

[0043]

[Chemical 11]

[In the formula, R ⁵⁵ and R ⁵⁶ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group which may have a substituent, an aryl group or an alkoxy group, and A is the same as defined above. Is. ]

[0045]

[Chemical 12]

[Wherein R ⁵⁷ , R ⁵⁸ , R ⁵⁹ , R ⁶⁰ , R ⁶¹ and R ⁶² are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and A is the same as defined above. is there. ]

[0047]

[Chemical 13]

[In the formula, R ⁶³ and R ⁶⁴ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, a nitro group,
It represents an alkyl group, an aryl group or an alkoxy group which may have a substituent, Ar represents an aryl group which may have a substituent, m represents 0 or 1, and A is the same as defined above. ]

[0049]

[Chemical 14]

[In the formula, R ⁶⁵ , R ⁶⁶ , R ⁶⁷ and R ⁶⁸ are
The same or different, it shows a hydrogen atom, a halogen atom, an alkyl group, an aryl group, or an alkoxy group, and A is the same as the above. ]

[0051]

[Chemical 15]

[In the formula, R ⁶⁹ and R ⁷⁰ are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkoxy group, and D and A are the same as defined above. In each of the above formulas, examples of the aryl group include the same groups as described above. As the alkyl group, in addition to the above groups, for example, octyl group, tert-octyl group, decyl group, hexadecyl group, dodecyl group, 2-hydroxyethyl group, carboxymethyl group, cyanomethyl group, 2-methoxyethyl group, Benzyl group, 2-phenylmethyl group, trifluoromethyl group, hydroxymethyl group, methoxymethyl group, dicyanomethyl group, aminomethyl group, N-methylaminomethyl group, mercaptomethyl group, methylthiomethyl group, N, N-dimethyl group Examples thereof include aminomethyl group, chloromethyl group, bromomethyl group and the like.

As the alkoxy group, in addition to the above groups,
For example, heptyloxy group, octyloxy group, nonyloxy group, 2-hydroxyethoxy group, carboxymethoxy group, cyanomethoxy group, 2-methoxyethoxy group, benzyloxy group, 2-methylphenoxy group, trifluoromethoxy group, hydroxy. Methoxy group, methoxy group, dicyanomethoxy group, aminomethoxy group,
N-methylaminomethoxy group, mercaptomethoxy group,
Examples thereof include methylthiomethoxy group, N, N-dimethylaminomethoxy group, chloromethoxy group and bromomethoxy group.

Examples of the heterocyclic group include thienyl group, pyrrolyl group, pyrrolidinyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group,
Examples thereof include an imidazolyl group, a 2H-imidazolyl group, a pyrazolyl group, a triazolyl group, a tetrazolyl group, a pyranyl group, a pyridyl group, a piperidyl group, a piperidino group, a 3-morpholinyl group and a morpholino group.

Examples of the coupler residue represented by A include groups represented by the general formulas (a) to (g).

[0056]

[Chemical 16]

In each formula, R ³⁰ represents a carbamoyl group, a sulfamoyl group, an allofanoyl group, an oxamoyl group, an anthraniloyl group, a carbazoyl group, a glycyl group, a hydantoyl group, a phthalamoyl group, and a succinamoyl group. These groups include a halogen atom, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a nitro group, a cyano group, an alkyl group, an alkenyl group, a carbonyl group, a carboxyl group and the like. It may have a substituent.

R ³¹ represents an atomic group necessary for forming an aromatic ring, a polycyclic hydrocarbon or a heterocyclic ring by condensing with R ³⁰ and the benzene ring having a hydroxyl group, and these rings are as described above. You may have the same substituent. R ³² represents an oxygen atom, a sulfur atom or an imino group. R ³³ represents a divalent chain hydrocarbon or aromatic hydrocarbon, and these groups may have the same substituents as described above.

R ³⁴ represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and these groups may have the same substituents as described above. R ³⁵ is a divalent chain hydrocarbon, an aromatic hydrocarbon, or the following formula (h) in the above general formulas (e) and (f).

[0060]

[Chemical 17]

It represents an atomic group necessary for forming a heterocycle with the moiety represented by, and these rings may have the same substituents as described above. R ³⁶ is a hydrogen atom, an alkyl group,
It represents an amino group, a carbamoyl group, a sulfamoyl group, an allofanoyl group, a carboxyl group, an ester of a carboxyl group, an aryl group, or a cyano group, and groups other than a hydrogen atom may have the same substituents as described above.

R ³⁷ represents an alkyl group or an aryl group, and these groups may have the same substituents as described above.
As the alkyl group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group,
Examples thereof include lower alkyl groups having 1 to 6 carbon atoms such as tert-butyl group, pentyl group and hexyl group.

Examples of the aryl group include phenyl group, tolyl group, xylyl group, biphenyl group, naphthyl group, anthryl group and phenanthryl group. Examples of the alkenyl group include lower alkenyl groups having 2 to 6 carbon atoms such as vinyl group, allyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2-pentenyl group and 2-hexenyl group. To be

Examples of the halogen atom include chlorine atom, bromine atom, iodine atom and fluorine atom. In R ³¹ , the atomic group necessary for forming an aromatic ring by condensing with R ³⁰ and a benzene ring having a hydroxyl group is, for example, an alkylene group such as a methylene group, an ethylene group, a propylene group or a butylene group. To be

The aromatic ring formed by the condensation of R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group is
Examples thereof include naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring and naphthacene ring. In R ³¹ , the atomic group necessary for condensation with R ³⁰ and a benzene ring having a hydroxyl group to form a polycyclic hydrocarbon is, for example, a methylene group, an ethylene group,
Examples thereof include alkylene groups having 1 to 4 carbon atoms such as propylene group and butylene group.

Examples of the polycyclic hydrocarbon formed by the condensation of R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group include a carbazole ring, a benzocarbazole ring, a dibenzofuran ring and the like. Further, in R ³¹ , an atomic group necessary for forming a heterocycle by condensing with R ³⁰ and a benzene ring having a hydroxyl group is, for example, a benzofuranyl group, a benzothiophenyl group, an indolyl group, a 1H-indolyl group, bezoxazolyl. Group, benzothiazolyl group, 1H-indaryl group, benzimidazolyl group, chromenyl group, chromanyl group, isochromanyl group, quinolinyl group, isoquinolinyl group, cinnolinyl group, phthalazinyl group, quinazonilyl group, quinoxalinyl group, dibenzofuranyl group, carbazolyl group, xanthenyl group , An acridinyl group, a phenanthridinyl group, a phenazinyl group, a phenoxazinyl group and a thianthrenyl group.

Examples of the aromatic heterocyclic group formed by condensing R ³¹ with R ³⁰ and a benzene ring having a hydroxyl group include, for example, thienyl group, furyl group, pyrrolyl group,
Oxazolyl group, isoxazolyl group, thiazolyl group,
Examples thereof include isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group and thiazolyl group. It may also be a heterocyclic group condensed with another aromatic ring (for example, a benzofuranyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a quinolyl group, etc.).

In R ³³ and R ³⁵ , examples of the divalent chain hydrocarbon include ethylene group, propylene group and butylene group, and examples of the divalent aromatic hydrocarbon include phenylene group, naphthylene group, Examples thereof include a phenanthrylene group. Examples of the heterocyclic group represented by R ³⁴ include a pyridyl group, a pyrazyl group, a thienyl group, a pyranyl group and an indolyl group.

In R ³⁵ , the atomic group necessary for forming a heterocycle with the moiety represented by the formula (h) is, for example, phenylene group, naphthylene group, phenanthrylene group, ethylene group, propylene group, butylene. Groups and the like. Examples of the aromatic heterocyclic group formed by R ³⁵ and the moiety represented by the formula (h) include, for example, benzimidazole group, benzo [f] benzimidazole group, dibenzo [e, g] benzimidazole group. Group, benzopyrimidine group and the like. These groups may have the same substituents as described above.

In the above R ³⁶ , examples of the carboxyl group ester include methyl ester, ethyl ester, propyl ester, butyl ester and the like. Specific examples of the coupler residue A represented by the general formulas (a) to (g) include the following groups.

[0071]

[Chemical 18]

[0072]

[Chemical 19]

[0073]

[Chemical 20]

[0074]

[Chemical 21]

Specific examples of the azo pigments include compounds represented by the following formulas (b1) to (b12).

[0076]

[Chemical formula 22]

[0077]

[Chemical formula 23]

[0078]

[Chemical formula 24]

[0079]

[Chemical 25]

As the perylene pigment, the following general formula can be used.
(3):

[0081]

[Chemical formula 26]

[In the formula, R ³ and R ⁴ are the same or different and each represents a hydrogen atom, a substituted or unsubstituted alkyl group having 18 or less carbon atoms, a cycloalkyl group, an aryl group, an aralkyl group or an alkaryl group. ] The compound represented by these is mentioned. Specific examples of the perylene-based pigment include compounds represented by the following formulas (c1) to (c7).

[0083]

[Chemical 27]

[0084]

[Chemical 28]

[0085]

[Chemical 29]

Examples of the squarylium salt pigment include those represented by the following general formula (4):

[0087]

[Chemical 30]

[Wherein R ⁵ and R ⁶ are the same or different,
Represents a halogen atom, an alkyl group or an alkoxy group,
R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are the same or different and each represents a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an allyl group, an aralkyl group or an alkaryl group. Further, these groups may have a halogen atom, an alkyl group, an alkoxy group or the like as a substituent. ] The compound represented by these is mentioned.

Further, as the polycyclic quinone pigment, for example, anthanthrone pigment, quinacridone pigment, perinone pigment, quinophthalone pigment, flavantron pigment, pyranthrone pigment, biolantron pigment, anthrone pigment, indanthrone pigment. Examples include pigments.
Examples of the charge transport material include various electron transport materials and hole transport materials.

Examples of the electron transport material among the charge transport materials include diphenoquinone compounds, benzoquinone compounds, naphthoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromoanil, 2,4. ，
7-trinitro-9-fluorenone, 2,4,5,7-
Tetranitro-9-fluorenone, 2,4,7-trinitro-9-dicyanomethylenefluorenone, 2,4
Electron-withdrawing property of 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, etc. Examples thereof include materials and those obtained by polymerizing these electron-withdrawing materials.

Examples of the hole transport material include diamine compounds such as phenylenediamine compounds and benzidine compounds, 2,5-di (4-methylaminophenyl) -1,
Diazole compounds such as 3,4-oxadiazole, 9
-Styryl compounds such as (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds Compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, nitrogen-containing cyclic compounds represented by triazole compounds,
Examples thereof include electron donating materials such as condensed polycyclic compounds.

These charge transport materials may be used alone or in combination of two or more. When using a charge transporting material having film-forming properties such as polyvinylcarbazole, the binder resin is not always necessary. Specific examples of the charge transport material include compounds represented by the following formulas (D1) to (D4), which belong to, for example, benzidine compounds.

[0093]

[Chemical 31]

Examples of the binder resin include styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic polymers, styrene-acrylic copolymers, Polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene,
Vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, thermoplastic resin such as polyether resin, silicone resin,
Examples thereof include epoxy resins, phenol resins, urea resins, melamine resins and other crosslinkable thermosetting resins, and photocurable resins such as epoxy-acrylate and urethane-acrylate. These binder resins can be used alone or in combination of two or more.

In the photosensitive layer, in addition to the above components, for example, a sensitizer, a fluorene compound, an ultraviolet absorber, a plasticizer,
Various additives such as an interfacial lubricant and a leveling agent can also be added. In order to improve the sensitivity of the photoconductor,
For example, a sensitizer such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generation material.

In the laminated photoreceptor, the charge generating material forming the resin type charge generating layer and the binder resin can be used in various proportions. The charge generating material is added to 100 parts by weight of the binder resin. 5 to 1000 parts by weight of generating material, especially 30 to 5
It is preferably used in a proportion of 00 parts by weight. On the other hand, the charge-transporting material and the binder resin that form the charge-transporting layer can be used in various proportions within a range that does not hinder the transport of charge and a range that does not crystallize, but in the charge-generating layer by light irradiation. The binder resin 1 so that the generated charges can be easily transported.
It is preferable to use the charge transport material in an amount of 10 to 500 parts by weight, particularly 25 to 200 parts by weight, based on 00 parts by weight.

The thickness of the laminated photosensitive layer is preferably 0.01 to 5 μm, particularly 0.1 to 3 μm for the charge generation layer, and 2 to 100 μm for the charge transport layer.
m, particularly preferably about 5 to 50 μm.
In a single-layer type photoreceptor, the charge generation material is 0.1 to 50 parts by weight, particularly 0.5 to 100 parts by weight with respect to the binder resin.
30 parts by weight, 20 to 500 parts by weight of the charge transport material, particularly 30 to 200 parts by weight are suitable. The thickness of the single-layer type photosensitive layer is 5 to 100 μm, particularly 10 to 50 μm.
It is preferable that the thickness is about m.

In the case of a single-layer type photoreceptor, it is between a conductive substrate and a photosensitive layer, and in the case of a laminated type photoreceptor, it is between a conductive substrate and a charge generating layer, and a conductive substrate. A barrier layer may be formed between the charge transport layer and the charge transport layer or between the charge generation layer and the charge transport layer to the extent that the characteristics of the photoreceptor are not impaired. It may be formed.

As the conductive substrate on which the above layers are formed, various conductive materials can be used.
For example, simple metals such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, and plastic materials in which the above metals are vapor-deposited or laminated, iodide Examples thereof include glass coated with aluminum, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the conductive substrate has sufficient mechanical strength when used. Each of the above layers, when formed by a coating method, as a solvent for forming a coating solution, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol, butanol,
Aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, dimethyl ether, diethyl ether and tetrahydrofuran. Examples include ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide and dimethyl sulfoxide. These solvents can be used alone or in combination of two or more. Further, in order to improve the dispersibility of the charge transport material or the charge generating material and the smoothness of the photosensitive layer surface, a surfactant, a leveling agent, etc. may be used.

The coating solution is prepared by dispersing and mixing each of the above-exemplified components and the above-mentioned components such as a solvent using a known method such as a roll mill, a ball mill, an attritor, a paint shaker or an ultrasonic disperser. To be done. Well-known means are used for coating and drying the coating liquid.

[0102]

EXAMPLES The present invention will be described below based on Examples and Comparative Examples. <Single Layer Type Photoreceptor> Examples 1 to 12 100 parts by weight of a bisphenol A type polycarbonate resin as a binder resin, 4 parts by weight of a charge generating material, 100 parts by weight of a charge transporting material and 100 parts by weight of an amidine compound. 2 parts by weight and 800 parts by weight of dichloromethane as a solvent were mixed and dispersed for 4 hours using a paint shaker to prepare a coating liquid for a single-layer type photosensitive layer.

The specific compounds of the amidine compounds used are shown in Table 4 below in the compound Nos.
Is shown. Further, the charge generating material and the charge transporting material are shown in Table 4 by using the reference numerals attached to the compounds exemplified above. Then, this coating solution is applied onto an aluminum sheet as a conductive base material by a bar coating method,
It was dried with hot air at 0 ° C. for 1 hour to form a single-layer type photosensitive layer having a film thickness of 20 μm, and an electrophotographic photosensitive member was manufactured.

Comparative Examples 1 to 4 Except that 2 parts by weight of a normal antioxidant represented by the following formulas (x1) and (x2) was added instead of the amidine compound.
Electrophotographic photoreceptors were manufactured in the same manner as in Examples 1 to 12 above.

[0105]

[Chemical 32]

[R in the formula (x1) is the following group (5):

[0107]

[Chemical 33]

It is ]

[0109]

[Table 4]

For the electrophotographic photoreceptors of the above-mentioned respective examples and comparative examples
Then, the following tests were conducted and the characteristics thereof were evaluated.Initial electrical characteristic test Sensitivity tester Shinshi made by GENTEC
A. Electrophotographic photoreceptors of Examples and Comparative Examples using 30M
Apply an applied voltage to the surface of the
The surface potential when electrified is defined as the initial surface potential Vo (V).
Measured. Also, if the exposure light source of the drum sensitivity tester
, Wavelength 550nm, light intensity 0.2mW / cm ²The red light of
Irradiate the surface of the photoconductor for 1 second, then 0.5 seconds from the start of irradiation.
The subsequent potential was measured as the residual potential Vr (V). Furthermore
In order to reduce the initial surface potential Vo (V) to half,
Measured time, half exposure amount E_1/2(ΜJ / cm²)
It was calculated.

Electrical characteristic test after printing durability The electrophotographic photoreceptors of Examples and Comparative Examples were mounted on an electrostatic copying machine (DC-1670M manufactured by Mita Industry Co., Ltd.),
After continuous copying of 10,000 sheets, the initial surface potential Vo (V) and the residual potential Vr (V) were measured in the same manner as above.
The half-exposure amount E _1/2 (μJ / cm ² ) was determined.

The above results are shown in Table 5.

[0113]

[Table 5]

From the results shown in Table 5 above, all the electrophotographic photoreceptors of Examples 1 to 12 to which the amidine compound was added,
Compared to Comparative Examples 1 to 4 in which a conventional antioxidant was added, the changes in the initial surface potential, the residual potential, and the half-exposure amount after the printing endurance were small, and thus it was found that they were more stabilized. . It was also found that the electrophotographic photoconductors of the above-mentioned respective examples have high residual sensitivity and low half-exposure amount as compared with the respective comparative examples, and thus have high sensitivity.

Electrical Property Test after Exposure to Nitrogen Oxide Among the Examples, the electrophotographic photoreceptors of Examples in which the results in Table 5 were good and the electrophotographic photoreceptors of Comparative Examples were prepared .
The sample was left in a closed container having a nitrogen oxide concentration of 55 ppm for 4 days and exposed to nitrogen oxide, and the initial surface potential Vo before and after the exposure was increased.
(V) was measured to determine the half-dose exposure amount E _1/2 (μJ / cm ² ).

The results are shown in Table 6.

[0117]

[Table 6]

From the results shown in Table 6, the electrophotographic photoreceptors of the respective examples show smaller changes in the initial surface potential, the residual potential and the half-exposure amount after the initial exposure and after the nitrogen oxide exposure, as compared with the comparative examples. Therefore, it was found that the stability against nitrogen oxide was excellent. <Layered Photoreceptor> Examples 13 to 21 To a solution of polyvinyl butyral as a binder resin in dichloromethane (concentration of resin is 30% by weight), a solution of charge generating material in dichloromethane (concentration of charge generating material is 5% by weight) is added. Then, they were mixed and dispersed for 4 hours using a paint shaker to prepare a coating liquid for the charge generating layer of the laminated photosensitive layer.
The weight ratio of the resin to the charge generating material in the coating liquid was resin: charge generating material = 5: 1.

Then, this coating solution was applied onto an aluminum sheet as a conductive base material by a bar coating method, and 1
It was dried with hot air at 00 ° C. for 1 hour to form a charge generation layer having a film thickness of 0.5 μm. Next, 100 parts by weight of a bisphenol A type polycarbonate resin as a binder resin, 100 parts by weight of a charge transport material and 1 part by weight of an amidine compound are mixed and dispersed together with 700 parts by weight of toluene as a solvent. Thus, a coating solution for the charge transport layer of the laminated photosensitive layer was prepared.

Then, this coating solution was applied onto the charge generation layer on the surface of the aluminum sheet by a bar coating method,
The film was dried with hot air at 120 ° C. for 1 hour to form a charge generation layer having a film thickness of 20 μm, and an electrophotographic photosensitive member having a laminated photosensitive layer was manufactured. The specific compounds of the amidine compounds used are the compounds N in Tables 1 to 3 shown in Table 7 below.
It is shown using o. In addition, the charge generation material and the charge transport material are shown in Table 7 by using the reference numerals attached to the compounds exemplified above.

Comparative Examples 5 to 8 Except that 2 parts by weight of a conventional antioxidant represented by the above formulas (x1) and (x2) was added instead of the amidine compound.
Electrophotographic photoreceptors were manufactured in the same manner as in Examples 13 to 21.

[0122]

[Table 7]

With respect to the electrophotographic photosensitive members of the above Examples and Comparative Examples, the same tests as the initial electrical property test and the electrical property test after printing were conducted, except that the charging potential was set to -800 V, and The characteristics were evaluated. The results are shown in Table 8.

[0124]

[Table 8]

From the results shown in Table 8, the electrophotographic photoreceptors of Examples 13 to 21 to which the amidine-based compound was added were compared with those of Comparative Examples 5 to 8 to which the conventional antioxidant was added. Since the changes in the initial surface potential, residual potential, and half-exposure amount after printing were small, it was found that they were stabilized. It was also found that the electrophotographic photoconductors of the above-mentioned respective examples have high residual sensitivity and low half-exposure amount as compared with the respective comparative examples, and thus have high sensitivity.

After the exposure to the nitrogen oxides, the electrophotographic photoreceptors of Examples and the electrophotographic photoreceptors of Comparative Examples, in which the results in Table 8 were good, were set to -800 V. The characteristics were evaluated by conducting the same test as the electric characteristics test. The results are shown in Table 9.

[0127]

[Table 9]

From the results shown in Table 9, the electrophotographic photoreceptors of the respective examples show smaller changes in the initial surface potential, residual potential and half-exposure amount after the initial exposure and after the nitrogen oxide exposure, as compared with the comparative examples. Therefore, it was found that the stability against nitrogen oxide was excellent.

[0129]

As described above in detail, since the electrophotographic photoreceptor of the present invention has an amidine compound having a specific structure added to the photosensitive layer, it has high stability to nitrogen oxides and high sensitivity. Moreover, it has a unique effect that it has excellent durability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sakae Saito 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Kogyo Co., Ltd. No. 28 Inside Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A charge-generating material and a charge-transporting material on a conductive substrate, and a compound represented by the general formula (1): [Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom,
It represents a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group. ] An electrophotographic photoreceptor comprising a photosensitive layer containing an amidine compound represented by