JPH0734119B2 - Electrophotographic photoreceptor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic photosensitive member that is preferably used in an image forming apparatus such as a copying machine.

(Prior Art) In recent years, as an electrophotographic photosensitive member having a photosensitive layer formed on a conductive substrate, an organic photosensitive member is used which has good processability and is advantageous in terms of manufacturing cost and has a large degree of freedom in functional design. Has been done. The above-mentioned organic photoreceptor has a photosensitive layer in which a charge generating function and a charge transporting function are separated by a charge generating material that generates a charge by light irradiation and a charge transporting material that transports the generated charge, thereby improving the sensitivity. There is known a function-separated type electrophotographic photoreceptor for achieving the above-mentioned purpose. The photosensitive layer of the function-separated electrophotographic photoreceptor is a laminated photoreceptor in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material and a binder resin are laminated. In addition, various types of single-layer type photoreceptors in which a charge generating material and a charge transporting material are dispersed in a binder resin have been proposed.

Since the laminated photoreceptor has various functions separated by the charge generation layer and the charge transport layer, it has an advantage that it has high sensitivity and a wide selection range of photosensitive materials, unlike the single-layer photoreceptor.

By the way, since many charge transport materials are of positive charge transport type and have a durable surface, a charge generation layer is provided on a conductive substrate, and a charge transport layer is further provided on the charge generation layer. It is common to have a body structure. However, in such a negative charging laminated photoreceptor, ozone is generated in the atmosphere at the time of negative charging to cause deterioration of the photoreceptor and pollution of the copying environment, and at the time of development, a positive charging toner which is difficult to manufacture is required. There is a problem such as

On the other hand, the above-mentioned single-layer type photoreceptor can be positively charged, and a negatively chargeable toner can be used as a toner for developing an electrostatic latent image on the photoreceptor. This is advantageous because, in general, it is easy to obtain a toner that is negatively charged, so that the selection range of toner materials is wide and various toner materials can be used. However, since electrons and holes are moved in one layer, one of them becomes a trap and the residual potential tends to increase. In addition, there is a problem that the combination of the charge generating material and the charge transporting material greatly affects the electrophotographic characteristics such as charging characteristics, sensitivity and residual potential.

Therefore, in view of the above problems, an electrophotographic photosensitive member (Japanese Unexamined Patent Publication No. 63-223651) in which dibromoanthanthrone and a diamine derivative are combined has been proposed.

(Problems to be Solved by the Invention) However, sufficient electrophotographic characteristics cannot be obtained with the above-mentioned photoconductor, and excellent electrophotographic characteristics such as charging characteristics, sensitivity, residual potential, etc. In particular, it is desired to develop a photoconductor having more excellent surface potential stability.

Therefore, it is an object of the present invention to provide a positively chargeable single-layer type electrophotographic photosensitive member which is excellent not only in electrophotographic characteristics such as charging characteristics, sensitivity and residual potential but also in repeated stability.

(Means and Actions for Solving Problems) Therefore, in the present invention, the following general formula [I] is used as a charge generating material in the binder resin. (Wherein R ¹ represents a halogen atom or an alkoxy group, and k represents an integer of 0 to 4), and a charge transporting material represented by the following general formulas [II] to [V]. (In the formula, R ^{2 to} R ¹⁷ are the same or different and each represents a hydrogen atom,
Represents a lower alkyl group, a lower alkoxy group or a halogen atom; Y represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom; n represents an integer of 1 to 3; l, m, o and p represent Indicates an integer of 0 to 2;
R ⁶ , R ⁷ , R ⁸ and R ⁹ are not simultaneously hydrogen atoms,
At least one of l 6, m, o and p of R ⁶ , R ⁷ , R ⁸ and R ⁹ which is not a hydrogen atom is 2) and at least one is selected from the group of diamine derivatives represented by Further, a hydrazone compound represented by the following general formula [VI], a fluorene compound represented by the following general formula [VII], and an m-phenylenediamine compound represented by the following general formula [VIII] (In the formula, R ¹⁸ represents a hydrogen atom or an alkyl group) (In the formula, R ¹⁹ , R ²⁰ , R ²¹ and R ²² represent a hydrogen atom or an alkyl group) (In the formula, R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , and R ^{27 each} represent an alkyl group, an alkoxy group, or a halogen atom, and each of them may be substituted with a phenyl group without any substitution, as long as it can be substituted. All the substituents may be the same or different from each other.) A photosensitive layer containing at least one selected from the group consisting of The above object was achieved by constructing the body.

As a result of earnest studies by the present inventors, the charge generation material comprises a dibenzopyrene compound represented by the general formula [I] and a charge transport material comprising a diamine derivative represented by the general formulas [II] to [V]. In the photoreceptor having a single-layer type photosensitive layer of a system containing at least one selected from the group in the binder resin, the hydrazone compound represented by the general formula [VI], the general formula [VII ] When at least one kind is selected from the group consisting of the fluorene-based compound represented by the above formula and the m-phenylenediamine-based compound represented by the general formula [VIII] and mixed, the copying process is repeated. It was found that a stable surface potential can be maintained.

(Preferred Embodiment of the Invention) The dibenzopyrene-based compound as the charge generating material used in the present invention is represented by the above general formula [I], and the halogen atom of R ^{1 in} the formula is fluorine, bromine or iodine. Is exemplified. Of the above halogen atoms, chlorine or bromine is preferable.

As the alkoxy group, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy,
Examples thereof include alkoxy groups having 1 to 6 carbon atoms such as tert-butoxy, pentyloxy and hexyloxy groups.

Specifically, dibenzo [def, mno] chrysene-6,12-dione, 2,8-dichloro-dibenzo [def, mno] chrysene-
6,12-dione, 4,10-dichloro-dibenzo [def, mno]
Chrysene-6,12-dione, 2,4,8,10-tetrachloro-dibenzo [def, mno] chrysene-6,12-dione, 2,8-dibromo-dibenzo [def, mno] chrysene-6,12 -Zeon,
4,10-dibromo-dibenzo [def, mno] chrysene-6,12
-Dione 2,4,8,10-tetrabromo-dibenzo (def, mn
o] chrysene-6,12-dione, 2,8-dichloro-4,10-dibromo-dibenzo [def, mno] chrysene-6,12-dione, 2,8-dimethoxy-dibenzo [def, mno] chrysene-
6,12-dione, 4,10-dimethoxy-dibenzo (def, mn
o) chrysene-6,12-dione, 2,8-diethoxy-dibenzo [def, mno] chrysene-6,12-dione, 4,10-diethoxy-dibenzo [def, mno] chrysene-6,12-dione,
2,4,8,10-tetramethoxy-dibenzo [def, mno] chrysene-6,12-dione, 2,4,8,10-tetraethoxy-dibenzo [def, mno] chrysene-6,12-dione, 2,8-dimethoxy-4,10-diethoxy-dibenzo [def, mno] chrysene-6,12-dione, 4,10-dipropoxy-dibenzo [de
f, mno] chrysene-6,12-dione, 4,10-diisopropoxy-dibenzo [def, mno] chrysene-6,12-dione,
4,10-dibutoxy-dibenzo [def, mno] chrysene-6,1
2-dione, 4,10-diisobutoxy-dibenzo (def, mn
o] chrysene-6,12-dione, 4,10-di-tert-butoxy-dibenzo [def, mno] chrysene-6,12-dione, 4,1
0-dipentyloxy-dibenzo [def, mno] chrysene-
6,12-dione, 4,10-dihexyloxy-dibenzo (de
Examples include f, mno] chrysene-6,12-dione and the like. Among the above dibenzopyrene compounds, 4,10-dibromo-dibenzo [def, mno] chrysene-6,12-dione is particularly preferable.

In addition, the halides and alkoxylates of the above-mentioned dibenzopyrene compounds are difficult to isolate and purify, and the positions of the above substituents may not be specified in some cases.

The dibenzopyrene-based compound represented by the general formula [I] is used alone or in combination of two or more.

As the diamine derivative as the charge transport material used in the present invention, the compounds represented by the above general formulas [II] to [V] are used.

Examples of the lower alkyl group in the general formulas [II] to [V] include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and hexyl groups. It Among the above lower alkyl groups, alkyl groups having 1 to 4 carbon atoms are preferable.

Examples of the lower alkoxy group include alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy and hexyloxy groups. Among the above lower alkoxy groups, an alkoxy group having 1 to 4 carbon atoms is preferable.

Further, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The substituents R ^{5 to} R ²⁰ and the substituent Y may be substituted at any position on the phenyl ring or the naphthyl ring.

In the diamine derivative represented by the general formula [II], preferable compounds among the p-phenylenediamine derivatives with n = 1 include, for example, 1,4-bis (N, N-diphenylamino) benzene and -(N, N-diphenylamino) -4- [N- (3-methylphenyl) -N-phenylamino] benzene, 1,4-bis [N- (2-methylphenyl) -N-phenylamino] benzene Other examples include the diamine derivatives described in JP-A No. 1-118143, P13 to P20.

In the diamine derivative represented by the general formula [II],
Among the benzidine derivatives of n = 2, preferred compounds include, for example, 3,3′-dimethyl-N, N, N ′, N′-tetrakis-4-methylphenyl (1,1′-biphenyl) -4,
Examples include 4'-diamine and the like.
The diamine derivative described in P21-P28 of the 3rd publication is illustrated.

In the diamine derivative represented by the general formula [II],
Among the 4,4 ″ -terphenyldiamine derivatives with n = 3,
Preferred compounds include, for example, 4,4 ″ -bis (N, N-
Diphenylamino) -1,1 ′: 4 ′, 1 ″ -terphenyl,
4,4 ″ -bis [N- (2-methylphenyl) -N-phenylamino] -1,1 ′: 4 ′, 1 ″ -terphenyl and the like are exemplified, and in addition, JP-A-1-118143, P28 The diamine derivatives described in P34 to P34 are exemplified.

In the diamine derivative represented by the general formula [III], as a preferable compound among the p-phenylenediamine derivatives with n = 1, for example, 1- [N- (3,
5-Dimethylphenyl) -N-phenylamino] -4-
Examples include (N, N-diphenylamino) benzene, 1- [N, N-di (3,5-dimethylphenyl) amino] -4- (N, N-diphenylamino) benzene, and the like. Examples of the diamine derivatives described in JP-A-118144, P13 to P21.

In the diamine derivative represented by the general formula [III], among the benzidine derivatives of n = 2, preferable compounds include, for example, 4- [N- (3,5-dimethylphenyl) -N-phenylamino]- Examples include 4 '-(N, N-diphenylamino) diphenyl, 4- [N, N-di (3,5-dimethylphenyl) amino] -4'-(N, N-diphenylamino) diphenyl, and others. Japanese Unexamined Patent Publication 1-1181
The diamine derivatives described in JP-A-44, P21 to P29 are exemplified.

In the diamine derivative represented by the general formula [III], among the 4,4 ″ -terphenyldiamine derivatives with n = 3, preferred compounds include 4- [N- (3,
5-dimethylphenyl) -N-phenylamino] -4 ″
-(N, N-diphenylamino) -1,1 ': 4', 1 "-terphenyl, 4- [N, N-bis (3,5-dimethylphenyl) amino] -4"-(N, N -Diphenylamino) -1,1 ':
Examples include 4 ′, 1 ″ -terphenyl, and the diamine derivatives described in JP-A-1-118144, P29 to P36.

Further, in the diamine derivative represented by the general formula [IV], among the p-phenylenediamine derivatives of n = 1,
Preferred compounds include, for example, 1,4-bis (N-naphthyl-N-phenylamino) benzene, 1- (N-naphthyl-N-phenylamino) -4- [N- (6-methylnaphthyl) -N -Phenylamino] benzene and the like, and other examples include the diamine derivatives described in JP-A 1-118145, P13 to P19.

In the diamine derivative represented by the general formula [IV],
Among the benzidine derivatives of n = 2, preferred compounds include, for example, 4,4′-bis (N-naphthyl-N-phenylamino) diphenyl and 4,4′-bis [N- (2-methylnaphthyl)- Examples thereof include N-phenylamino] diphenyl, and the diamine derivatives described in JP-A No. 1-118145, P19 to P25.

In the diamine derivative represented by the general formula [IV],
Among the 4,4 ″ -terphenyldiamine derivatives with n = 3,
Preferred compounds include, for example, 4,4 "-bis (N-
Naphthyl-N-phenylamino) -1,1 ': 4', 1 "-terphenyl, 4,4" -bis [N- (2-methylnaphthyl) -N-phenylamino] -1,1 ': 4 ′, 1 ″ -terphenyl and the like are exemplified, and in addition, JP-A-1-118145
The diamine derivative described in P25 to P30 is exemplified.

In the diamine derivative represented by the general formula [V], among the p-phenylenediamine derivatives of n = 1,
Preferred compounds include, for example, 1,4-bis (N, N-dinaphthylamino) benzene, 1- (N, N-dinaphthylamino) -4- [N- (6-methylnaphthyl) -N-naphthyl Amino] benzene and the like are listed as examples.
The diamine derivative described in 1-118146 gazette P13-P22 is illustrated.

In the diamine derivative represented by the general formula [V],
Among the benzidine derivatives of n = 2, preferred compounds include, for example, 4,4′-bis (N, N-dinaphthylamino)
Examples include diphenyl, 4,4'-bis [N- (3-methylnaphthyl) -N-naphthylamino] diphenyl, and the diamine derivatives described in JP-A No. 1-118146, P22 to P30. .

In the diamine derivative represented by the general formula [V],
Among the 4,4 ″ -terphenyldiamine derivatives with n = 3,
Preferred compounds include, for example, 4,4 ″ -bis (N, N-
Dinaphthylamino) -1,1 ′: 4 ′, 1 ″ -terphenyl,
4,4 ″ -bis [N- (3-methylnaphthyl) -N-naphthylamino] -1,1 ′: 4 ′, 1 ″ -terphenyl and the like are exemplified, and in addition, JP-A-1-118146, P30 ~ The diamine derivative of P38 is illustrated.

The diamine derivatives represented by the general formulas [II] to [V] are used alone or in combination of two or more. The diamine derivative has good molecular symmetry, and is
(N, N-diethylamino) benzaldehyde N, N-diphenylhydrazone and N-methyl-3-carbazolylaldehyde N, N-diphenylhydrazone do not cause isomerization reaction by light irradiation, resulting in photostability. Not only is it excellent, but the drift mobility is high, and the dependence of the drift mobility on the electric field strength is small.

As the binder resin used in the present invention, various ones, for example, a styrene polymer, an acrylic polymer, a styrene-acrylic polymer, polyethylene, an ethylene-vinyl acetate copolymer, a chlorinated polyethylene, a polypropylene. ,
Olefin-based polymers such as ionomer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester,
Alkyd resin, polyamide, polyurethane, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl phthalate, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, and photocurable resin such as epoxy acrylate. Polymers can be used, but the sensitivity of the photoconductor is improved, the abrasion resistance and repeatability of the photoconductor are excellent, and the selection range of the solvent that dissolves the binder resin is wide (4,4 ').
-Cyclohexylidenediphenyl) carbonate is preferred. When poly (4,4′-cyclohexylidenediphenyl) carbonate is used, tetrahydrofuran is different from bisphenol A type polycarbonate, which has conventionally been able to use only chlorine-based solvents such as dichloromethane and monochlorobenzene from the viewpoint of solution stability. Since a solvent such as methyl ethyl ketone can also be used, it is preferable in terms of safety and hygiene and is easy to handle. Among the above poly (4,4′-cyclohexylidenediphenyl) carbonates, the molecular weight is 15,000 to 25,000 and the glass transition point is 58 ° C.
Something is preferable.

The use ratio of the dibenzopyrene-based compound, the diamine derivative and the binder resin is not particularly limited and can be appropriately selected according to the desired characteristics of the electrophotographic photoreceptor, etc., but the binder resin is 100 parts by weight. On the other hand, the dibenzopyrene compound is used in an amount of 2 to 20 parts by weight, preferably 3 to 15 parts by weight, a diamine derivative of 40 to 200 parts by weight, and preferably 50 to 100 parts by weight. If the amount of the dibenzopyrene-based compound and the diamine derivative used is less than the above amount, not only the sensitivity of the photoconductor is insufficient but also the residual potential becomes large. On the other hand, if it exceeds the above range, the abrasion resistance of the photoconductor becomes insufficient.

Furthermore, in a single-layer type photoreceptor containing a dibenzopyrene compound and a diamine derivative in a binder resin, a hydrazone compound represented by the general formula [VI], represented by the general formula [VII] A fluorene compound represented by the general formula [V
III] and one of the m-phenylenediamine compounds represented by the formula [VII].
Two types in which the hydrazone compound represented by the general formula [VI] is combined with the fluorene compound represented by the above or the m-phenylenediamine compound represented by the general formula [VIII] is combined. By selecting and mixing, it is possible to prevent a decrease in surface potential during repeated copying processes and maintain a stable surface potential.

The alkyl group in the above general formulas [VI], [VII] and [VIII] is an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and hexyl groups. Is exemplified.
Examples of the alkoxy group in the general formula [VIII] include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy and hexyloxy groups. Further, examples of the halogen atom in the general formula [VIII] include fluorine, chlorine, bromine and iodine atoms.

Examples of the hydrazone compound represented by the general formula [VI] include 3-carbazolylaldehyde N, N-diphenylhydrazone and N-methyl-3-carbazolylaldehyde N, N.
-Diphenylhydrazone, N-ethyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-propyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-isopropyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-butyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-
Isobutyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-tert-butyl-3-carbazolylaldehyde N, N-diphenylhydrazone, N-pentyl-3-carbazolylaldehyde N, N-diphenylhydrazone , N-hexyl-3-carbazolyl aldehyde N, N
-Diphenylhydrazone and the like are exemplified, but among them, N
-Ethyl-3-carbazolyl aldehyde N, N-diphenylhydrazone is preferred.

Examples of the fluorene compound represented by the general formula [VII] include 9-carbazolyliminofluorene and 9- (3-
Methylcarbazolylimino) fluorene, 9- (3,6-
Dimethylcarbazolylimino) fluorene, 9- (3,6
-Diethylcarbazolylimino) fluorene, 9- (3
-Ethyl-6-methylcarbazolylimino) fluorene, 9- (3,6-dipropylcarbazolylimino) fluorene, 9- (3,6-diisopropylcarbazolylimino) fluorene, 9- (3,6 -Dibutylcarbazolylimino) fluorene, 9- (3,6-diisobutylcarbazolylimino) fluorene, 9- (3,6-di-tert-butylcarbazolylimino) fluorene, 9- (3,6- Dipentylcarbazolylimino) fluorene, 9- (3,6-
Dihexylcarbazolylimino) fluorene, 9- (3,
6-Dimethylcarbazolylimino) -3-methylfluorene, 9- (3,6-dimethylcarbazolylimino) -3,6
-Dimethylfluorene, 9- (3,6-dimethylcarbazolylimino) -3,6-diethylfluorene, 9- (3,6-
Examples thereof include dimethylcarbazolylimino) -3-ethylfluorene, and among them, 9-carbazolyliminofluorene is preferable.

Examples of the m-phenylenediamine compound represented by the general formula [VIII] include N, N, N ', N'-tetraphenyl-1,3
-Phenylenediamine, N, N, N ', N'-tetrakis (3
-Tolyl) -1,3-phenylenediamine, N, N, N ', N'-
Tetraphenyl-3,5-tolylenediamine, N, N, N ', N'
-Tetrakis (3-tolyl) -3,5-tolylenediamine, N, N, N ', N'-tetrakis (4-tolyl) -1,3-phenylenediamine, N, N, N', N'- Tetrakis (4-tolyl) -3,5-tolylenediamine, N, N, N ', N'-tetrakis (3-ethylphenyl) -1,3-phenylenediamine, N, N, N', N'- Tetrakis (4-propylphenyl) -1,3-phenylenediamine, N, N, N ′, N′-tetraphenyl-5-methoxy-1,3-phenylenediamine,
N, N-bis (3-tolyl) -N ', N'-diphenyl-1,3
-Phenylenediamine, N, N'-bis (4-tolyl)-
N, N'-diphenyl-1,3-phenylenediamine, N, N '
-Bis (4-tolyl) -N, N'-bis (3-tolyl)-
1,3-phenylenediamine, N, N'-bis (4-tolyl)
-N, N'-bis (3-tolyl) -3,5-tolylenediamine, N, N'-bis (4-ethylphenyl) -N, N'-bis (3-ethylphenyl) -1,3 -Phenylenediamine,
N, N'-bis (4-ethylphenyl) -N, N'-bis (3
-Ethylphenyl) -3,5-tolylenediamine, N, N,
N ', N'-tetrakis (2,4,6-trimethylphenyl)-
1,3-phenylenediamine, N, N, N ', N'-tetrakis (2,4,6-trimethylphenyl) -3,5-tolylenediamine, N, N, N', N'-tetrakis (3 , 5-Dimethyl) -1,3
-Phenylenediamine, N, N, N ', N'-tetrakis (3,5
-Dimethyl) -3,5-tolylenediamine, N, N, N ', N'-
Tetrakis (3,5-diethyl) -1,3-phenylenediamine, N, N, N ', N'-tetrakis (3,5-dimethyl) -3,5
-Tolylenediamine, N, N, N ', N'-tetrakis (3-
Chlorophenyl) -1,3-phenylenediamine, N, N,
N ', N'-tetrakis (3-bromophenyl) -1,3-phenylenediamine, N, N, N', N'-tetrakis (3-iodophenyl) -1,3-phenylenediamine, N, N , N ′,
N'-tetrakis (3-fluorophenyl) -1,3-phenylenediamine and the like are exemplified, but among them, the interaction between molecules becomes small due to poor symmetry of molecules, and conversely with resin. Since it has a property that it is extremely difficult to crystallize because it has a large interaction and can be sufficiently dissolved in the resin, R ²³ , R ²⁴ , R ²⁶ , and R ²⁷ in the general formula [VIII] are meta-positioned with respect to the nitrogen atom. Or a compound having R ²³ and R ²⁷ in the para position with respect to the nitrogen atom and R ²⁴ and R ²⁶ in the meta position with respect to the nitrogen atom is preferable. Specifically, N, N, N ′, N′-tetrakis (3-
Tolyl) 1,3-phenylenediamine, N, N′-bis (4-
Tolyl) -N, N'-bis (3-tolyl) -1,3-phenylenediamine.

The above-mentioned compound can be used in an appropriate amount according to the characteristics of the photoreceptor, but when a hydrazone-based compound is used among the above-mentioned compounds, a diamine-based compound and a hydrazone-based compound as a charge transport material are used. 95: 5 to 90:10
It is preferable to contain it in the photosensitive layer in a weight ratio of.

When a fluorene compound is used among the above compounds, it is preferable that the diamine compound and the fluorene compound as the charge transport material are contained in the photosensitive layer in a weight ratio of 90:10 to 80:20. .

Further, when the m-phenylenediamine-based compound is used among the above-mentioned compounds, the diamine-based compound and the m-phenylenediamine-based compound as the charge transport material are 75: 2.
The weight ratio of 5 to 25:75, especially 70:30 to 50:50, is preferably contained in the photosensitive layer.

That is, if the photosensitive layer contains each of the above compounds in a ratio smaller than the above weight ratio, the repeating characteristics are not sufficient, and if the above compounds are contained in a ratio exceeding the above weight ratios, the repeating characteristics become high, but the sensitivity and the like are increased. It will not be enough.

Further, since the dibenzopyrene-based compound has no spectral sensitivity on the long wavelength side, in order to further improve the sensitivity when the single-layer electrophotographic photoreceptor of the present invention is combined with a halogen lamp having a large red spectral energy, It is preferable to use a phthalocyanine-based compound such as metal-free phthalocyanine or oxotitanyl phthalocyanine, which has spectral sensitivity on the long wavelength side.

As the metal-free phthalocyanine, the Bragg angle (2θ ± 0.2 °) is 7.5 °, 9.1 °, 16.7 °, 17.3 °, 2
The X type having a strong diffraction peak at 2.3 ° is preferable.
When 1.25 to 3.75 parts by weight of the X-type metal-free phthalocyanine is added to 100 parts by weight of the dibenzopyrene-based compound, the spectral sensitivity region shifts to the longer wavelength side, and the sensitivity of the photoreceptor becomes higher. However, the addition of 1.25 parts by weight or less of X-type metal-free phthalocyanine to 100 parts by weight of the dibenzopyrene compound does not produce the sensitizing effect on the long wavelength side. Further, X-type metal-free phthalocyanine was added to 3.7 parts by weight per 100 parts by weight of the dibenzopyrene-based compound.
On the contrary, if 5 parts by weight or more is added, the spectral sensitivity on the long wavelength side becomes high, and the reproducibility of the red original document deteriorates.

Examples of the oxotitanyl phthalocyanine include:
The following general formula [IX] having various crystal types such as α type, β type, γ type, δ type and ε type (In the formula, X represents a halogen atom, and q represents 0 or an integer of 1 or more). Examples include oxotitanyl phthalocyanine. In particular, the halogen atom in the general formula [IX] is bromine or Chlorine, q is 0,
Bragg angle (2θ ± 0.2 in X-ray diffraction spectrum
°) is 6.9 °, 9.6 °, 15.6 °, 17.6 °, 21.9 °, 23.6
Α-type oxotitanyl phthalocyanine which shows strong diffraction peaks at °, 24.7 ° and 28.0 ° and has the largest diffraction peak at 6.9 ° among the Bragg angles is preferable.

Since the dibenzopyrene-based compound has no spectral sensitivity on the long wavelength side, the oxotitanyl phthalocyanine is added in an amount of 0.62 to 1.8 per 100 parts by weight of the dibenzopyrene-based compound.
By adding 8 parts by weight, the spectral sensitivity region shifts to the long wavelength side, and the sensitivity of the photoconductor becomes higher when combined with a halogen lamp having a large red spectral energy. However, the sensitizing effect on the long wavelength side does not occur only by adding 0.62 parts by weight or less of oxotitanyl phthalocyanine to 100 parts by weight of the dibenzopyrene-based compound. When 1.88 parts by weight or more of oxotitanyl phthalocyanine is added to 100 parts by weight of the dibenzopyrene-based compound, the spectral sensitivity on the long wavelength side is increased, and the reproducibility of the red original document is deteriorated.

In addition, when an antioxidant is used in combination, it is possible to preferably prevent deterioration of a charge transporting material or the like having a structure that is affected by oxidation and is inexpensive, due to oxidation.

As the above-mentioned antioxidant, 2,6-di-tret-butyl-p
-Cresol, triethylene glycol-bis [3-
(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], penta Erythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-] Hydroxyphenyl) propionate], 2,2-thiobis (4-
Methyl-6-tert-butylphenol), N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,
Examples thereof include phenolic antioxidants such as 4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene. Among them, 2,6-di-tret-butyl-p -Cresol is preferred.

The photoconductor of the present invention can be obtained by preparing a coating solution containing each of the above-mentioned components, coating the coating solution on a conductive substrate, and drying.

The conductive substrate may be in the form of a sheet or drum containing conductivity, various materials having conductivity, for example, the surface is alumite-treated, or untreated aluminum, aluminum alloy, Copper, tin, platinum,
A metal simple substance such as gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, or brass, or a layer of the above metal, indium oxide, tin oxide or the like was formed by means of vapor deposition or the like. Examples of the plastic material and glass include aluminum, which is preferably anodized by the sulfuric acid alumite method and sealed with nickel acetate.

In addition, the conductive substrate may be subjected to a surface treatment with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, if necessary, to enhance the adhesion to the photosensitive layer.

In adjusting the coating solution, an appropriate organic solvent is used according to the type of binder resin used, and examples of the organic solvent include methanol, ethanol, propanol, isopropanol, butanol and the like. Alcohols, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane, carbon tetrachloride, halogenated hydrocarbons such as chlorobenzene, tetrahydrofuran and ethylene glycol. Examples of various solvents include ethers such as dimethyl ether and ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and esters such as ethyl acetate and methyl acetate. One solvent or a mixture of two or more solvents is used. Further, when adjusting each of the above-mentioned coating solutions, in order to improve dispersibility, coatability, etc., silicone oil such as polydimethylsiloxane, a leveling agent such as a surfactant, or terphenyl, halonaphthoquinones, acenaphthylene, etc. Various additives such as conventionally known sensitizers may be used in combination.

Each of the above-mentioned coating liquids, etc. is a conventional mixing and dispersing method, for example,
It can be adjusted by using a paint shaker, a mixer, a ball mill, a sand mill, an attritor, an ultrasonic disperser, etc., and when applying the obtained dispersion liquid or the like, a conventionally used coating method, for example, dip coating or spray coating. , Spin coating, roller coating, blade coating, curtain coating, bar coating, etc. are adopted.

The single-layer type photosensitive layer of the electrophotographic photosensitive member of the present invention may have an appropriate thickness, but is 15 to 30 μm, and particularly 18 to 27 μm.
Those having a thickness of are preferable.

(Example) Below, this invention is demonstrated in detail based on an Example.

Example 1 100 parts by weight of poly (4,4′-cyclohexylidenediphenyl) carbonate (trade name Polycarbonate Z, manufactured by Mitsubishi Gas Chemical Co., Inc.), 4,10-dibromo-dibenzo [def, mno]
Chrysene-6,12-dione 8 parts by weight, X-type metal-free phthalocyanine (manufactured by Dainippon Ink and Chemicals, Inc.) 0.2 parts by weight, 3,3'-
Diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -4,4'-diamine 95 parts by weight, N-ethyl-3-carbazolylaldehyde N, N Mix 5 parts by weight of diphenylhydrazone, 5 parts by weight of antioxidant (Kawaguchi Chemical Co., Ltd., trade name Antage BHT), 0.01 parts by weight of polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd.) and a predetermined amount of tetrahydrofuran with an ultrasonic disperser. An electrophotographic photosensitive member is prepared by dispersing and preparing a dispersion liquid for a single-layer type photosensitive layer, applying it on an alumite-treated aluminum base tube to form a photosensitive layer having a thickness of about 23 μm, and heat treating at about 100 ° C. It was created.

Example 2 3,3'-Diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -used in Example 1
Instead of 4,4'-diamine, 4,4'-bis [N- (3,5-
A single-layer type electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that dimethylphenyl) -N-phenylamino] biphenyl was used.

Example 3 3,3'-Diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -used in Example 1
A single-layer electron was prepared in the same manner as in Example 1 except that 4,4′-bis [N- (6-methylnaphthyl) -N-phenylamino] biphenyl was used instead of 4,4′-diamine. A photographic photoreceptor was created.

Example 4 3,3'-Diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -used in Example 1
A single-layer type electron was prepared in the same manner as in Example 1 except that 4,4′-bis [N- (6-methylnaphthyl) -N-naphthylamino] biphenyl was used instead of 4,4′-diamine. A photographic photoreceptor was created.

Example 5 A single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 10 parts by weight of 9-carbazolyliminofluorene was added.

Example 6 3,3'-Diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -used in Example 1
Using 30 parts by weight instead of 95 parts by weight of 4,4'-diamine, N-
Ethyl-3-carbazolyl aldehyde N, N-diphenylhydrazone except that 5 parts by weight of N, N, N ', N, -tetrakis (3-tolyl) -1,3-phenylenediamine are used instead of 5 parts by weight. In the same manner as in Example 1, a single-layer type electrophotographic photoreceptor was prepared.

Example 7 Instead of N, N, N ', N',-tetrakis (3-tolyl) -1,3-phenylenediamine used in Example 6, N, N'-bis (4-tolyl) -N, A single-layer type electrophotographic photosensitive member was prepared in the same manner as in Example 6 except that N'-bis (3-tolyl) -1,3-phenylenediamine was used.

Example 8 Further, a single-layer type electrophotographic photosensitive member was prepared in the same manner as in Example 6 except that 10 parts by weight of 9-carbazolyliminofluorene was added.

Comparative Example 1 3,3′-diethyl-N, N, N ′, N, -tetrakis-4 without addition of N-ethyl-3-carbazolylaldehyde N, N-diphenylhydrazone used in Example 1 -Methylphenyl (1,1'-biphenyl) -4,4'-diamine A single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 100 parts by weight was used instead of 95 parts by weight. did.

Comparative Example 2 3,3'-diethyl-N, N, N ', N'-tetrakis-4-methylphenyl (1,1'-biphenyl) -used in Example 1
In the same manner as in Example 1 except that 4,4'-diamine was not added and 100 parts by weight was used instead of 5 parts by weight of N-ethyl-3-carbazolylaldehyde N, N-diphenylhydrazone. A layer type electrophotographic photoreceptor was prepared.

Comparative Example 3 3,3-Diethyl-N, N, N ', N, -tetrakis-4-without adding N-ethyl-3-carbazolylaldehyde N, N-diphenylhydrazone used in Example 1 Methylphenyl (1,1'-biphenyl) -4,4'-diamine was replaced with 95 parts by weight of 4,4'-bis [N- (6-methylnaphthyl) -N-
A single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 100 parts by weight of phenylamino] biphenyl was used.

Then, in order to examine the charging characteristics and the photosensitive characteristics of the electrophotographic photoreceptors obtained in the above-mentioned Examples and Comparative Examples, an electrostatic copying test apparatus (Gentec Cynthia 30 manufactured by Gentec Co., Ltd.) was used.
M) was used to positively charge each of the electrophotographic photoconductors.

The surface potential V _SP (V) of each electrophotographic photosensitive member was measured, and the surface potential V _SP (V) was exposed to the surface of the electrophotographic photosensitive member using a tungsten lamp having an illuminance of 10 lux.
_Calculate the time until _SP becomes 1/2, and reduce the half exposure E1 / 2
(ΜJ / cm ² ) was calculated. The surface potential 0.15 seconds after the exposure was taken as the residual potential V _rp (V).

Further, it was also examined whether or not the surface potential was lowered by repeated use 1000 times. By the repeated use of the photoreceptor, the surface potential of the photoreceptor was reduced by 100 V or more was evaluated as ×, and the reduction in the range of 50 to 100 V was evaluated as Δ, and only 50 V or less was evaluated as ○. .

Furthermore, after copying a gray original with the same lightness as red and measuring the reflection density of the obtained copy with a reflection densitometer, The red reproducibility was examined by calculating The red reproducibility of 70% or less was evaluated as x, the range of 70 to 100% was evaluated as Δ, and the 100% or more was evaluated as o.

Table 1 shows the results of the charging characteristics, the photosensitive characteristics, etc. of the electrophotographic photosensitive members obtained in the above Examples and Comparative Examples.

As is clear from Table 1, the electrophotographic photoreceptors of Examples 1 to 8 all have excellent charging characteristics and high sensitivity,
It was found that the residual potential was small and the repeatability and red color reproducibility were good. On the other hand, the electrophotographic photoreceptors of Comparative Examples 1 to 3 are all excellent in red color reproducibility, but their repetitive characteristics are insufficient, and the electrophotographic photoreceptors of Comparative Example 2 are sensitive. Was low and the residual potential was high.

(Effects of the Invention) As described above, according to the electrophotographic photosensitive member of the present invention, the charging characteristics are excellent, the sensitivity is high, the residual potential is small, and further the repeating characteristics and the red color reproducibility are excellent. Further, since it is a single-layer type photoreceptor, not only is it positively charged positively, but also it has a unique effect that it can be easily manufactured with high yield and is inexpensive.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Maeda 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Mitao Suma Examiner, Mita Industry Co., Ltd.

Claims (6)

[Claims] 1. A charge generating material in a binder resin, represented by the following general formula [I]: (Wherein R ¹ represents a halogen atom or an alkoxy group, and k represents an integer of 0 to 4), and a charge transporting material represented by the following general formulas [II] to [V]. (In the formula, R ^{2 to} R ¹⁷ are the same or different and each represents a hydrogen atom,
Represents a lower alkyl group, a lower alkoxy group or a halogen atom; Y represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a halogen atom; n represents an integer of 1 to 3; l, m, o and p represent Indicates an integer of 0 to 2;
R ⁶ , R ⁷ , R ⁸ and R ⁹ are not simultaneously hydrogen atoms,
At least one of l 6, m, o and p of R ⁶ , R ⁷ , R ⁸ and R ⁹ which is not a hydrogen atom is 2) and at least one is selected from the group of diamine derivatives represented by Further, it further comprises a hydrazone compound represented by the following general formula [VI], a fluorene compound represented by the following general formula [VII], and an m-phenylenediamine compound represented by the following general formula [VIII]. An electrophotographic photosensitive member comprising a conductive substrate on which a photosensitive layer containing at least one selected from the group is formed. (In the formula, R ¹⁸ represents a hydrogen atom or an alkyl group) (In the formula, R ¹⁹ , R ²⁰ , R ²¹ and R ²² represent a hydrogen atom or an alkyl group) (In the formula, R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , and R ^{27 each} represent an alkyl group, an alkoxy group, or a halogen atom, and each of them may be substituted with a phenyl group without any substitution, as long as it can be substituted. And all the substituents may be the same or different from each other). 2. The electrophotographic photosensitive member according to claim 1, wherein R ^{2 to} R ¹⁷ are the same or different and each is an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. 3. The electrophotographic photosensitive member according to claim 1, wherein Y is an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. 4. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains metal-free phthalocyanine or oxotitanyl phthalocyanine. 5. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains an antioxidant. 6. The electrophotographic photosensitive member according to claim 1, wherein the dibenzopyrene compound is 4,10-dibromo-dibenzo [def, mno] chrysene-6,12-dione.