JPS63271453A - Organic photosensitive body - Google Patents

Abstract

PURPOSE:To obtain an org. photosensitive body stable to light, heat, etc., and ensuring superior image quality by incorporating a benzotriazole UV absorber into the photosensitive layer of a photosensitive body contg. a hydrazone compd. CONSTITUTION:When a photosensitive layer contg. a hydrazone compd. represented by the formula (where R<1> is H or lower alkyl) as an electric charge transferring material is formed to obtain a photosensitive body, a benzotriazole UV absorber such as 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole or 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotria-zole is incorporated into the photosensitive layer. Though the hydrazone compd. is used, the photosensitive layer is stabilized to light, heat, etc., and a clear image is obtd. because the benzotriazole UV absorber is incorporated into the photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an organic photoreceptor, and more particularly to an organic photoreceptor suitable as an electrophotographic photoreceptor.

<Problems to be solved by conventional technology and inventions> In recent years,
As a photoreceptor for electrophotography, an organic photoreceptor is used because it has good processability and is advantageous in terms of manufacturing cost, and also has a large degree of freedom in functional design. In particular, functionally separated organic photoreceptors are becoming more and more popular because they can achieve higher sensitivity by separating each function using a charge-generating material that generates a charge when irradiated with light and a charge-transporting material that transports the generated charge. It is being Furthermore, a photoreceptor containing a hydrazone compound as the charge transporting material is known (Japanese Patent Application Laid-Open No. 2007-270764).
(See Japanese Patent Application Laid-Open No. 81-270766).

However, the above-mentioned hydrazone-based compounds are not stable against light such as sunlight or white fluorescent lamps, especially short-wavelength light of about 430 NO+ or less, or heat, and the above-mentioned hydrazone-based compounds may be isomerized or dioxidized by light irradiation. Therefore, when a photoreceptor containing the hydrazone compound is exposed to light during maintenance or the like, the sensitivity of the photoreceptor decreases, and the surface potential and residual potential of the photoreceptor increase, causing fog in the copied image area. There is a problem in that image quality deteriorates.

<Purpose of the Invention> The present invention has been made in view of the above-mentioned problems, and although it contains a hydrazone compound, it is stable against light and heat, and even when exposed to light, sensitivity etc. decreases. The purpose of the present invention is to provide an organic photoreceptor with excellent image quality without any image quality.

Means and Effects for Solving the Problems> In order to achieve the above objects, the organic photoreceptor of the present invention has a photoreceptor layer containing a hydrazone compound as a charge transport material, wherein the photoreceptor layer comprises: It is characterized by containing a benzotriazole ultraviolet absorber.

According to the organic photoreceptor having the above structure, even though a hydrazone compound is used, the photosensitive layer contains a benzotriazole ultraviolet absorber, so even when the photoreceptor is irradiated with light, the hydrazone compound is It is thought that the benzotriazole ultraviolet absorber absorbs the short wavelength light that causes photodeterioration of the hydrazone compound, thereby stabilizing the photosensitive layer.

The present invention will be explained in detail below.

The above-mentioned hydrazone compounds include various ones, such as diethylaminobenzaldehyde N.

N-diphenylhydrazone, N,N-diphenylaminobenzaldehyde N,N-diphenylhydrazone, etc.
Conventionally known ones can be used, but in combination with the above benzotriazole ultraviolet absorber, the sensitivity of the photoreceptor,
In order to obtain a photoreceptor having a high surface potential and a low residual potential, it is preferable to use it in combination with a hydrazone compound represented by the following general formula (1).

(In the formula, R1 represents a hydrogen atom or a lower alkyl group) Examples of the lower alkyl group in the above general formula (1) include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tart-butyl, pentyl, hexyl group, etc. An alkyl group having 1 to 6 carbon atoms is exemplified.

The hydrazone compounds represented by the above general formula (1) include 3-carbazolylaldehyde N,N-diphenylhydrazone, N-methyl-3-carbazolylaldehyde N,N-diphenylhydrazone, and N-ethyl- 3-carbazolyl aldehyde N, N-diphenylhydrazone,
N-propyl-3-carbazolyl aldehyde N,N-
Diphenylhydrazone, N-isopropyl-3-carbazolyl aldehyde N, N-diphenylhydrazone, N
-Butyl-3-carbazolyl aldehyde N.

N-diphenylhydrazone, N-isobutyl-3-carbazolyl aldehyde N,N-diphenylhydrazone,
N-tart-butyl-3-carbazolyl aldehyde
N, N-diphenylhydrazone, N-pentyl-3-carbazolyl aldehyde N.

N-diphenylhydrazone, N-hexyl-3-carbazolyl aldehyde N,N-diphenylhydrazone is exemplified. Among the above hydrazone compounds, the number of carbon atoms is 1 or more
those having 3 alkyl groups, especially N-methyl-3-
Carbazolyl aldehyde N,N-diphenylhydrazone is preferred. The above hydrazone compounds may be used alone or in combination of two or more.

Furthermore, various types of benzotriazole-based ultraviolet absorbers can be used.

Among the benzotriazole ultraviolet absorbers, preferred are 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5
-ethylphenyl)benzotriazole, 2- (2-
hydroxy-5-propylphenyl)benzotriazole, 2-(2-hydroxy-5-isopropylphenyl)benzotriazole, 2-(2-hydroxy-5
-butylphenyl)benzotriazole, 2- (2-
hydroxy-5-isobutylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-
5-pentylphenyl)benzotriazole, 2-(
2-hydroxy-5-hexylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dimethylphenyl)benzotriazole, 2-(2-hydroxy-
3,5-diethylphenyl)benzotriazole, 2-
(2-hydroxy-3-methyl-5-ethylphenyl)benzotriazole, 2-(2-hydroxy-3,5
-dipropylphenyl)benzotriazole, 2-(2
-Hydroxy-3,5-dibutylphenyl)benzotriazole, 2-(2-hydroxy-3゜5-diisobutylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole , 2-(2-hydroxy-3-tart
-butyl-5-methylphenyl)benzotriazole,
2- (2-hydroxy-3,5-diethylphenyl)
Benzotriazole, 2-(2-hydroxy-3,5-
diethylphenyl)benzotriazole, 2- (2-
Hydroxy-5-methylphenyl)-5-chlorobenzotriazole, 2- (2-hydroxy-3゜5-dimethylphenyl)-5-chlorobenzotriazole, 2-
(2-hydroxy-3-methyl-5-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2
-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3-tOrt-butyl-5-methylphenyl)-
Examples include 5-chlorobenzotriazole. Among the above ultraviolet absorbers, especially 2-(2-hydroxy-3
゜5-di-tart-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3-te
rt-Butyl-5-methylphenyl)-5-chlorobenzotriazole is preferred. Further, the above-mentioned ultraviolet absorbers may be used alone or in combination of two or more.

Further, the above-mentioned ultraviolet absorber is used in an appropriate amount depending on the characteristics of the photoreceptor, the photostabilization of the hydrazone-based compound, etc.
Preference is given to using 20 parts by weight, especially 20 to 80 parts by weight. If the amount of the ultraviolet absorber is less than 10 parts by weight, effects such as photostabilization will not be noticeable, and if it exceeds 120 parts by weight, the ultraviolet absorber will recrystallize and the characteristics of the photoreceptor will deteriorate.

Incidentally, there are many known UV absorbers such as 2-hydroxy-4-methoxybenzophenone,
When the hydrazone compound is used, it is not very effective in photostabilizing the photoreceptor.

In addition, together with the above benzotriazole ultraviolet absorber,
When an antioxidant is used in combination, the stability and repeatability of the photoreceptor can be further improved.

Various antioxidants can be used as the above antioxidants, such as nonylphenyl phosphite and N-phenylnaphthylamine;
, 5-di-tert-butyl-4-hydroxytoluene, 2,2-methylenebis(4-methyl-6-tart
-butylphenol), 2,2'-methylenebis(4-
ethyl-6-tart-butylphenol), 4.4-
-methylenebis(2,6-tcrt-butylphenol), 4゜4゛-bis(2,6-tert-butylphenol), 4.4"-methylenebis(6-tar
t-butyl-0-cresol), 1,3.5-)listyl-2,4,6-)lis(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 4゜4゛-
Alkylphenol antioxidants such as butylidene bis(6-tert-butyl-m-cresol), especially 3,
5-di-tert-butyl-4-hydroxytoluene is preferred. The above antioxidants may be used singly or in combination of two or more.

The above antioxidant can be used in an appropriate amount, but 1 to 10 parts by weight per 100 parts by weight of the hydrazone compound.
Preference is given to using 0 parts by weight, especially 5 to 30 parts by weight.

If the amount of the antioxidant is less than 1 part by weight, it will be difficult to stabilize the photoreceptor, and if it exceeds 100 parts by weight, the sensitivity will decrease.

Furthermore, in order to increase the sensitivity of the photoreceptor and reduce the surface potential and residual potential after repeated use, it is preferable that the photosensitive layer further contains a fluorene compound. Various types of fluorene compounds can be used, but those represented by the following general formulas (2) and (3) are preferred.

(In the formula, R2, R3, R4, R5, R6 and R7 are
(In the formula, R2, R3, Re and R9 are the same or different and represent a hydrogen atom or a lower alkyl group.) The lower alkyl group of the general formula (1) is exemplified.

Among the compounds of the general formula (2), preferred are 9-(N,N-diphenylhydrazino)fluorene, 9-[N-(4-methylphenyl)-N-phenylhydrazinocofluorene, 9 -[N,N-di(4-methylphenyl)hydrazinocofluorene, 9- [N,N-
Di(4-ethylphenyl)hydrazinocofluorene, 9
- [N-(4-methylphenyl)-N-(4-ethylphenyl)hydrazinocofluorene, 9-[N,N-
di(4-propylphenyl)hydrazinocofluorene,
9-[N,N-di(4-isopropylphenyl)hydrazinocofluorene, 9-[N,N-di(4-butylphenyl)hydrazinocofluorene, 9-[N,N-
di(4-pentylphenyl)hydrazinocofluorene,
9-[N,N-di(4-hexylphenyl)hydrazinocofluorene, 9-[N,N-di(3-methylphenyl)hydrazinocofluorene, 9-[N,N-di(3
-ethylphenyl)hydrazinocofluorene, 9- [
N-(3-methylphenyl)-N-(4-methylphenyl)hydrazinocofluorene, 9- [N-(3-ethylphenyl')-N-(4-ethylphenyl)hydrazinocofluorene, 9- [N,N-di(4,4-methylphenyl)hydrazino]-3,6-dimethylfluorene, 9-[N,N-di(4-methylphenyl)hydrazino]-3,6-dinitylfluorene, 9- [N, N-
Examples include di(4-ethylphenyl)hydrazino]-3,6-dimethylfluorene, 9-[N,N-di(4-ethylphenyl)hydrazino]-3,6-dinitylfluorene, and the like.

Further, among the compounds represented by the above general formula (3), preferable ones include 9-carbazolyliminofluorene, 9-(3-methylcarbazolylimino)fluorene,
9-(3,6-dimethylcarbazolylimino)fluorene, 9-(3,6-dinitylcarbazolylimino)fluorene, 9-(3-ethyl-6-methylcarbazolylimino)fluorene, 9 -(3,6-dipropylcarbazolylimino)fluorene, 9-(3,6-diitubropylcarbazolylimino)fluorene, 9-(3
゜6-Sibutylcarbazolylimino)fluorene, 9-
(3,6-dibutylcarbazolylimino)fluorene, 9- (3,6-tart-butylcarbazolylimino)fluorene, 9- (3,6-dipentylcarbazolylimino)fluorene, 9- (3,6-dihexylcarbazolylimino)fluorene, 9-(3,
6-dimethylcarbazolylimino)-3-methylfluorene, 9-(3,6-dimethylcarbazolylimino)-
Examples include 3,6-dimethylfluorene, 9-(3,6-dimethylcarbazolylimino)-3,6-dinitylfluorene, 9-(3-methylcarbazolylimino)-3-ethylfluorene, etc. be done.

Among the compounds of the above general formulas ω) and (3), especially 9-
(N,N-diphenylhydrazino)fluorene and 9-carbazolyliminofluorene are preferred.

The above-mentioned fluorene compounds may be used alone or in combination of two or more.

The fluorene compound may be used in an appropriate amount depending on the characteristics of the photoreceptor, but 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the hydrazone compound. , more preferably 10 to 30 parts by weight. If the amount of the fluorene compound is less than 1 part by weight, it will be difficult to further increase the photostability of the photoreceptor, and if it exceeds 100 parts by weight, the photostability will increase but the sensitivity of the photoreceptor will not be sufficient. It will no longer be.

Note that the fluorene compounds of the above general formulas (2) and (3) can stabilize various hydrazone compounds and increase the sensitivity of photoreceptors, but the fluorene compounds of the above general formulas (1)
It is particularly effective when combined with a hydrazone compound.

Further, in order to prevent photodeterioration of the photoreceptor and eliminate changes in electrical characteristics due to light irradiation, etc., the photosensitive layer preferably further contains a halogenated quinone. Examples of the halogenated quinones include benzoquinone, 1,2-
Examples include naphthoquinone, 1,4-naphthoquinone, and anthraquinone.

Various halogenated quinones can be used, but halogenated benzoquinone and halogenated naphthoquinone are preferred. Among the halogenated benzoquinones, preferred are 2-chloro-1,4-benzoquinone, 2,5-dichloro-1,4-benzoquinone, and 2-chloro-1,4-benzoquinone.
, 6-dichloro-1,4-benzoquinone, 2,5-difluoro-1,4-benzoquinone, 2,6-difluoro-
1゜4-benzoquinone, 2,5-dibromo-1,4-benzoquinone, 2,6-dibromo-1,4-benzoquinone, 2-chloro-5-bromo-1,4-benzoquinone, 2
, 5-short-1,4-benzoquinone, 2,6-diiodo-1,4-benzoquinone, and the like.

Among the halogenated naphthoquinones, preferred are 2-chloro-1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, and 2,5-dichloro-1
, 4-naphthoquinone, 2゜7-dichloro-1,4-naphthoquinone, 2,3-difluoro-1,4-naphthoquinone, 2,3-dibromo-1,4-naphthoquinone, 2-chloro-3- Examples include bromo-1,4-naphthoquinone and 2,3-short-1,4-naphthoquinone. Among the halogenated benzoquinones and halogenated naphthoquinones, especially 2,5-dichloro-1,4-penzoquinone,
2,6-dichloro-1,4-benzoquinone and 2,3
-dichloro-1,4-naphthoquinone is preferred. The above halogenated quinones may be used alone or in combination of two or more. Further, halogenated quinones can be used in an appropriate amount, but 5 parts by weight per 100 parts by weight of the hydrazone compound.
It is preferred to use up to 50 parts by weight, especially 10 to 40 parts by weight. If the amount used is less than 5 ffi 2 parts, it will be difficult to further prevent photodeterioration of the photoreceptor, and if it exceeds 50 parts by weight, the sensitivity will decrease.

Note that the above-mentioned hydrazone compounds may be used in combination with other charge transport materials, etc., as long as the photosensitivity characteristics etc. are not impaired. Examples of the other charge transport materials include tetracyanoethylene, fluorenone compounds such as 2,4.7-dolinitro-9-fluorenone, and nitrated compounds such as 2,4.8-)linitrothioxanthone and dinitroanthracene. , succinic anhydride, maleic anhydride, dibromomaleic anhydride, oxadiazole compounds such as 2,5-di(4-dimethylaminophenyl')-1,3,4-oxadiazole, 9-(4- styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, 1-phenyl-3-(
Pyrazoline compounds such as p-dimethylaminophenyl) pyrazoline, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, etc. Examples include nitrogen-containing cyclic compounds and fused polycyclic compounds.

In addition, in order to increase the sensitivity of the photosensitive layer by separating the functions of charge generation by light irradiation and transport of the generated charge, the above-mentioned hydrazone compounds are used together with charge generation materials and binder resins, and are used to create conductive A photoreceptor in which a single-layer photoreceptor layer in which the charge generation material and a charge transport material such as a hydrazone compound are dispersed in a binder resin is formed on a support substrate;
A photoreceptor having a double-layered photosensitive layer in which a charge generation layer containing the charge generation material described above and a charge transport layer containing a charge transport material such as the hydrazone compound are laminated on a conductive support substrate. is configured.

Examples of the charge generating material include selenium, selenium-
Tellurium, amorphous silicon, pyrylium salt, azo pigment, disazo pigment, anthanthrone pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigment, threne pigment, toluidine pigment, pyrazoline pigment, quinacridone pigment Various materials can be used, but in order to obtain a photoreceptor with excellent sensitivity, high surface potential, and low residual potential, perylene compounds, especially perylene compounds represented by the following general formula (4), are used. Preferably, they are used in combination.

(In the formula, R10, R11, R12 and R13 are the same or different and represent a lower alkyl group or a lower alkoxy group.) Examples of the lower alkyl group include the same lower alkyl groups as in the general formula (1) above. be done. In addition, the above general formula (4
Examples of the lower alkoxy group in ) include alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, pentyloxy, and hexyloxy groups.

The perylene compounds represented by the above general formula (1) include N,N''-di(3,5-dimethylphenyl)perylene-3,4,9,10-tetracarboxydiimide, N,
N”-di(3-methyl-5-ethylphenyl)perylene-3,4,9,to-tetracarboxydiimide, N,
N″-di(3,5-diethylphenyl)perylene-3,
4,9,10-tetracarboxydiimide, N, N--
Di(3,5-dipropylphenyl)perylene-3,4,
9,10-tetracarboxydiimide, N, N=-di(
3゜5-diisopropylphenyl)perylene-3,4゜9.10-tetracarboxydiimide, N,N--di(
3,5-dibutylphenyl)perylene-3゜4, 9.
10-Tetracarboxydiimide, N.

N--di(3,5-di-tart-butylphenyl)perylene-3,4,9,10-tetracarboxydiimide, N,N--di(3,5-diethylphenyl)perylene-3,4, 9,10-tetracarboxydiimide, N,
N--di(3,5-diethylphenyl)perylene-3,
4,9,10-tetracarboxydiimide, N, N=-
Di(3-methyl-5-methoxyphenyl)perylene-3
,4,9゜10-tetracarboxydiimide, N,N"
-di(3-methyl-5-ethoxyphenyl)perylene-
3,4,9,10-tetracarboxydiimide, N, N
--di(3-ethyl-5-methoxyphenyl)perylene-3,4,9,10-tetracarboxydiimide, N,
N-di(3-propyl-5-methoxyphenyl)perylene-3,4,9,10-tetracarboxydiimide,
N, N”-di(3°5-dimethoxyphenyl)perylene-3,4,9°10-tetracarboxydiimide, N,
N--di(3,5-jethoxyphenyl)perylene-3
゜4, 9.10-tetracarboxydiimide, NIN
゛-di(3,5-dipropoxyphenyl)perylene-3
,4,9,10-tetracarboxydiimide, N,N''
-di(,3,5-diisobutoxyphenyl)perylene-3,4,9,10-tetracarboxydiimide, N,
N--di(3,5-dibutoxyphenyl)perylene-3
,4,9,to-tetracarboxydiimide,N,N”
-di(3,5-dipentyloxyphenyl)perylene-
3,4゜9, IO-tetracarboxydiimide, N, N
--Di(3,5-dihexyloxyphenyl)perylene-3,4,9,10-tetracarboxydiimide and the like are exemplified. Among the above perylene compounds, the number of carbon atoms is 1 to
Those having 3 alkyl or alkoxy groups, particularly N,N--di(3,5-dimethylphenyl)perylene-3,4,9,10-tetracarboxydiimide, are preferred. Note that the charge generating materials such as the above-mentioned perylene compounds may be used alone or in combination of two or more kinds.

In addition, various binder resins can be used, such as styrene polymers, acrylic polymers, styrene-acrylic copolymers, polyethylene, ethylene-vinyl acetate copolymers, chlorinated polyethylene, polypropylene, and ionomers. Olefin polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl Various polymers can be used, such as butyral resin, polyether resin, phenol resin, xylylene resin, and photocurable resins such as epoxy acrylate.
Poly(4,4-cyclohexylidene diphenyl) carbonate is preferred because it has excellent abrasion resistance and cyclic properties of the photoreceptor and has a wide range of solvents for dissolving the binder resin. When using the above poly(4,4-cyclohexylidene diphenyl) carbonate, unlike bisphenol A type polycarbonate, for which conventionally only chlorinated solvents such as dichloromethane and monochlorobenzene could be used from the viewpoint of solution stability, Since ketone solvents such as tetrahydrofuran and methyl ethyl ketone can also be used, they are preferable from the viewpoint of safety and hygiene and are easy to handle. In addition,
The above poly(4,4”-cyclohexylidene diphenyl)
Various carbonates can be used, such as those with a polymerization degree of 5.
About 0 to 5000 can be used. Further, the above-mentioned binder resins may be used alone or in combination of two or more.

Note that, among the above-mentioned binder resins, the xylylene resin greatly contributes to stabilization of the photoreceptor, etc., similarly to the above-mentioned benzotriazole-based ultraviolet absorber. That is, the xylylene resin is useful in preventing photodeterioration of the photoreceptor, has excellent compatibility with the polycarbonate, and exhibits little change in sensitivity, surface potential, and residual potential with repeated use.

Therefore, the xylylene resin is preferably used in combination with polycarbonate. The above xylylene resin can be used in various ratios, but polycarbonate resin 1
10 to 50 parts by weight! In part, especially 20~
Preferably, 40 parts by weight are used. If the amount of xylylene resin used is less than 10 parts by weight, the above effects will not be sufficient,
If it exceeds 50 parts by weight, the mechanical strength of the photosensitive layer will decrease.

Further, the photosensitive layer may contain a conventionally known sensitizer such as terphenyl and acenaphthylene.

Furthermore, a combination of the hydrazone compound of general formula (1), the benzotriazole ultraviolet absorber, the perylene compound of general formula (4), and a binder resin is also useful as a multilayer photoreceptor. However, it exhibits particularly excellent photosensitive characteristics as a single-layer photoreceptor. More specifically, the single-layer type photoreceptor described above has good productivity because it can be obtained by simply preparing a dispersion of the material, coating it on a conductive substrate, and drying it. - In addition, in the case of the above-mentioned single-layer photoconductor, not only can it be positively charged, but also a toner that is negatively charged can be obtained as a toner for developing an electrostatic latent image on the photoconductor. There is an advantage that there is a wide selection range and that various toner materials can be used. On the other hand, the above-mentioned single-layer type photoreceptor does not have sufficient sensitivity, and the material constituting the photosensitive layer must be strictly selected, and the selection range of materials for the photosensitive layer is narrow. In addition, the above-mentioned single-layer photoreceptor has a low surface potential during corona charging and a large residual potential, and the surface potential decreases with repeated use, so it does not have sufficient repeatability and is not sufficient as an organic photoreceptor. The disadvantage is that it does not exhibit any specific characteristics. However, when a single-layer type photosensitive layer is constructed by combining the hydrazone compound of the general formula (1), the benzotriazole ultraviolet absorber, and the perylene compound of the general formula (4), it has excellent positive chargeability and sensitivity. Moreover, an inexpensive single-layer organic photoreceptor having a high surface potential, a small residual potential, and excellent repeatability can be obtained.

When forming a single-layer photosensitive layer using the hydrazone compound, charge generating material, and binder resin, the proportion of the materials used can be appropriately selected depending on the desired characteristics of the organic photoreceptor. However, 40 to 110 parts by weight of the hydrazone compound, preferably 6 parts by weight, per 100 parts by weight of the binder resin.
0 to 90 parts by weight of charge generating material, 2 to 20 parts by weight, preferably 5 to 10 parts by weight. If the amount of the hydrazone compound and charge generating material used is less than the above-mentioned amounts, not only the sensitivity of the photoreceptor will not be sufficient, but also the residual potential will increase. Further, if the amount exceeds the above range, the abrasion resistance of the photoreceptor will not be sufficient.

In addition, in a photoreceptor having a single-layer type photosensitive layer, if a large amount of the above-mentioned perylene-based compound is used, the positive chargeability will usually become insufficient, and if a small amount is used, the sensitivity etc. will decrease. By combining with the perylene compound, even if the amount of the perylene compound is small, it is possible to obtain an organic photoreceptor that has high sensitivity and surface potential, has a small residual potential, and is excellent in positive chargeability.

Note that the above perylene compounds may have spectral sensitivity on the short wavelength side. Therefore, in applications requiring color reproducibility in the blue region, it is preferable to use various spectral sensitizers, and it is particularly preferable to use phthalocyanine compounds.

Various types of phthalocyanine compounds can be used, but metal-free phthalocyanine is preferred.

The metal-free phthalocyanine may have an appropriate particle size, but preferably has an average particle size of 0.1 μm or less. The average particle size of metal-free phthalocyanine is 0.1
If it exceeds μm, the sensitivity of the photoreceptor decreases. The above average particle diameter was determined by a light scattering method (device name: dynamic light scattering photometer).

Further, metal-free phthalocyanine can be used in an appropriate amount, but 0.000 parts by weight per 100 parts by weight of the above-mentioned binder resin.
It is preferable to add 2 to 1 part by weight. If the amount added is less than 0.2 parts by weight, the blue reproducibility will not be sufficient, and if it exceeds 1 part by weight, the metal-free phthalocyanine will have spectral sensitivity in the red region, resulting in insufficient red reproducibility.

In addition, among the above metal-free phthalocyanines, β-type metal-free phthalocyanine, especially the average particle size of 0.005
Those having a diameter of 0.05 μm are preferred. When the average particle size of the β-type metal-free phthalocyanine is less than 0.005 μm, the dispersibility is insufficient, and when it exceeds 0.05 μm, the sensitivity of the photoreceptor decreases.

Furthermore, in order to enhance the stability of the photoreceptor containing the metal-free phthalocyanine, it is preferable to use a phthalocyanine pigment such as aluminum phthalocyanine or titanyl phthalocyanine, especially copper phthalocyanine, together with the metal-free phthalocyanine. Further, copper phthalocyanine can be used in an appropriate amount, but 1 to 10% by weight, particularly 3 to 10% by weight, based on the metal-free phthalocyanine.
Preferably, 10% by weight is used. If the amount of copper phthalocyanine is less than 1% by weight, it is not sufficient to stabilize the metal-free phthalocyanine, and if it exceeds 10% by weight, the surface potential will decrease. Note that as the amount of copper phthalocyanine increases, the stabilizing effect of metal-free phthalocyanine increases, and the residual potential of the photoreceptor also decreases.

Further, it is even more preferable to use the copper phthalocyanine in combination with the β-type metal-free phthalocyanine, and in this case, the average particle size of the copper phthalocyanine is 0.0.
It is preferable to use one with a diameter of 0.01 μm or less. Special 1,
In order to obtain a stable organic photoreceptor with a small residual potential by reducing the amount of copper phthalocyanine, it is preferable to co-precipitate the copper phthalocyanine with metal-free phthalocyanine. The above coprecipitation can be carried out by a conventional method,
For example, this can be carried out by dropping a sulfuric acid solution of steel phthalocyanine and metal-free phthalocyanine into water or the like during the production of copper phthalocyanine. The phthalocyanine obtained by the above-mentioned coprecipitation not only becomes fine particles of copper phthalocyanine, but also almost eliminates deterioration of electrical properties due to the thermal history of the photoreceptor, and also provides a photoreceptor with low residual potential and excellent color reproducibility. It will be done. In addition, in the phthalocyanine produced by the above coprecipitation method, in order to improve blue reproducibility with a small amount, the average particle size of the copper phthalocyanine is 0.
．． 001 μm or less is preferable.

The above-mentioned conductive substrate may be in the form of a sheet or a drum, and it is preferable that the substrate itself is conductive or the surface of the substrate is conductive and has sufficient mechanical strength when used. . Various conductive materials can be used as the conductive substrate, such as aluminum, copper,
tin, platinum, gold, silver, vanadium, molybdenum, chromium,
Examples include simple metals such as cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, plastic materials on which the above metals are vapor-deposited or laminated, and glass coated with aluminum iodide, tin oxide, indium oxide, etc. . Among the above-mentioned conductive substrates, aluminum is preferable, and in particular, aluminum crystal grains are not present on the surface, preventing the occurrence of black spots, pinholes, etc. in copied images, etc., and containing the above-mentioned hydrazone compound etc. In order to improve the adhesion between the photosensitive layer and the substrate, alumite-treated aluminum, especially alumite-treated aluminum in which the thickness of the alumite-treated layer is 5 to 12 μ- and the surface roughness is 1.5s or less, is preferable. .

When forming a photoreceptor having a single-layer photosensitive layer using the above-mentioned hydrazone compound, benzotriazole ultraviolet absorber, charge generating material, binder resin, etc., the photosensitive layer is
It may have an appropriate thickness, but preferably has a thickness of 3 to 50 μl, particularly 5 to 20 μl, and prepares a dispersion of the above-mentioned hydrazone compound, etc., and applies it to a conductive substrate. Formed by removing the solvent.

Further, the photoreceptor having the multilayer photosensitive layer includes a charge generation layer having a thickness of about 1 to 5 μm made of the charge generation material and a binder resin, and the hydrazone compound, benzotriazole ultraviolet absorber, etc. and a binder resin with a thickness of 5 to 50 mm.
It is obtained by sequentially forming a charge transport layer, in particular a charge transport layer of 10 to 20 μm, on a conductive substrate. Note that the charge generation layer of the multilayer photosensitive layer may be formed by vapor deposition, sputtering, or other means using a charge generation material without using a binder resin.

Further, when preparing the dispersion liquid of the above-mentioned hydrazone compound, etc., various organic solvents can be used depending on the type of binder resin etc. used. As the above solvent, n-
Aliphatic hydrocarbons such as hexane, octane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, dichloromethane, dichloroethane, carbon tetrachloride,
Halogenated hydrocarbons such as chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, cyclohexanone, esters such as ethyl acetate, methyl acetate, Various solvents are exemplified, such as dimethylformamide and dimethyl sulfoxide, which may be used singly or in combination of two or more. In addition, when preparing the above-mentioned dispersion, a surfactant, a leveling agent, etc. may be used in combination in order to improve dispersibility, coating properties, etc.

Further, the above-mentioned dispersion liquid can be prepared using a conventional method such as a ball mill, a paint shaker, a sand mill, an attritor, an ultrasonic disperser, etc., and the obtained dispersion liquid is applied to the conductive substrate. The organic photoreceptor of the present invention can be obtained by heating and removing the solvent.

Although the photosensitive layer of the organic photoreceptor of the present invention uses a hydrazone compound, since the photosensitive layer contains a benzotriazole ultraviolet absorber, the hydrazone compound and thus the photosensitive layer are stabilized.

That is, the organic photoreceptor of the present invention is not only stable against light and heat, and even when exposed to light, sensitivity etc. do not decrease and the surface potential and residual potential of the photoreceptor do not increase.
Clear copied images can be obtained with excellent image quality. Therefore, the organic photoreceptor of the present invention is useful as a photoreceptor used in various applications such as copying machines and laser printers.

<Examples> The present invention will be described in more detail below based on Examples.

Example I N,N--di(3,5-dimethylphenyl)perylene-
8 parts by weight of 3,4,9,10-tetracarboxydiimide, N-ethyl-3-carbazolyl aldehyde N,N-
75 parts by weight of diphenylhydrazone, 2-(2-hydroxy-3-tcrt-butyl-5-methylphenyl)-5
- 10 parts by weight of chlorobenzotriazole (trade name mark LA-36, manufactured by Adeka Argus), metal-free phthalocyanine (trade name Heliogen Blue-780, manufactured by BASF)
0) Using 0.6 parts by weight, 100 parts by weight of poly(4,4''-cyclohexylidene diphenyl) carbonate (product name Polycarbonate Z manufactured by Mitsubishi Gas Chemical Co., Ltd.) and a predetermined amount of tetrahydrofuran, an ultrasonic disperser was used. A dispersion was prepared and coated on an alumite-treated aluminum plate to produce a single-layer organic photoreceptor having a photosensitive layer with a thickness of approximately 20 μm.

Example 2 In place of 10 parts by weight of 2-(2-hydroxy-3-tort-butyl-5-methylphenyl)-5-chlorobenzotriazole in Example 1, 2-(2-hydroxy-3
Using 50 parts by weight of -tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, the above Example 1
An organic photoreceptor was prepared in the same manner as above.

Example 3 In place of 10 parts by weight of 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole in Example 1, 2-(2-hydroxy-3
An organic photoreceptor was prepared in the same manner as in Example 1 using 100 ffi parts of -tert-butyl-5-methylphenyl)-5-chlorobenzotriazole.

Example 4 In place of 2-(2-hydroxy-3,5-di-tert-butyl)-5-chlorobenzotriazole in Example 2, phenyl)-5-chlorobenzotriazole (trade name Tinupin 327, manufactured by Ciba Geigy Japan)
), an organic photoreceptor was produced in the same manner as in Example 1 above.

Example 5 In addition to the materials of Example 2, 3.5- as an antioxidant
An organic photoreceptor was prepared in the same manner as in Example 1 using 10 parts by weight of di-tert-butyl-4-hydroxytoluene (trade name: Sumilizer BIT, manufactured by Sumitomo Chemical Co., Ltd.).

Comparative Example 1 In the material of Example 1, 2-(2-hydroxy-3
An organic photoreceptor was prepared in the same manner as in the above example except that -tort-butyl-5-methylphenyl)-5-chlorobenzotriazole was not used.

Comparative Example 2 Using 2-hydroxy-4-methoxybenzophenone in place of 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobencitriazole in Example 1, An organic photoreceptor was prepared in the same manner as above.

Comparative Example 3 10 parts by weight of 2-(2-hydroxy-3-tort-butyl-5-methylphenyl)-5-chlorobenzotriazole of Example 1 was replaced with 3.5-di-te of Example 5.
An organic photoreceptor was obtained in the same manner as in Example 1 using 20 parts by weight of rt-butyl-4-hydroxytoluene.

Then, the following characteristics were investigated using the following methods.

(a) Photosensitive characteristics and surface potential In order to investigate the charging characteristics, photosensitivity, etc. of the electrophotographic photoreceptor described above, an electrostatic copying paper tester (manufactured by Kawaguchi Electric Co., Ltd., 5P-4) was used.
The organic photoreceptors of each of the Examples and Comparative Examples were positively charged by performing corona discharge under conditions of +8.0 KV (7).

In addition, the surface potentials Vs, p, (V) of each photoreceptor were measured, and the photoreceptor surface was exposed to light using a tungsten lamp with the illumination intensity adjusted to 10 lux. V s, p, is 1/2
Find the time until it becomes half-decreased exposure mE1/2 (μJ
/aJ) was calculated. In addition, the surface potential after 0.15 seconds has passed after exposure is the residual potential V r,p.

(V).

(b) Photodegradability After irradiating each of the above organic photoreceptors for 5 minutes with a 1000 lux white fluorescent lamp, the photosensitivity and surface potential were measured in the same manner as in (a) above. Differences between photosensitive characteristics and surface potential, etc., are expressed as tL ΔV s, p,
, ΔE 1/2 and ΔV r,p.

(C) Repetition characteristics and image characteristics The above organic photoreceptor was installed in a copying machine (Model DC-111 manufactured by Sanda Kogyo Co., Ltd.), and 10 copies were made using dry toner, and the initial surface potential and 10 copies were The surface potential of the photoreceptor after copying was measured in the same manner as in (a) above. Further, after one copy was made using the above copying machine, each photoreceptor was irradiated with light in the same manner as in (b) above, and 10 copies were made. and 1
The difference in fog between the 1st copy image and the 10th copy image was visually determined. Please note that there is almost no fogging.
, those with a large degree of fog were evaluated as X.

(d) Comprehensive evaluation A comprehensive evaluation of the above-mentioned various properties was carried out, and those with excellent properties as organic photoreceptors were rated as 0, and those with poor properties were rated as X.

The results of the charging characteristics, photosensitivity characteristics, repeatability characteristics, etc. of each organic photoreceptor obtained in the above Examples and Comparative Examples are shown in the following table.

(Hereinafter, blank space) As is clear from the table, all of the organic photoreceptors of the present invention have a small half-life exposure amount, have good sensitivity, and can be repeatedly irradiated with light without deteriorating the photosensitivity characteristics etc. due to light irradiation. There is little change in surface potential and residual potential even after use. It was also found that no residual potential was accumulated, the repeatability was excellent, and there was almost no fog in the copied images. On the other hand, all of the photoreceptors of Comparative Examples suffered from photodeterioration, resulting in decreased sensitivity and increased surface potential and residual potential due to repeated use. Further, repeated use caused increased fog in the copied images.

<Effects of the Invention> As described above, according to the organic photoreceptor of the present invention, although a hydrazone compound is used, the photosensitive layer does not contain a benzotriazole ultraviolet absorber among ultraviolet absorbers. As a result, the hydrazone compound and, in turn, the photosensitive layer are stabilized against light, heat, and the like. Therefore, even if the organic photoreceptor is exposed to light, the sensitivity etc. will not decrease or the surface potential and residual potential of the photoreceptor will not increase, and in addition, a clear copy image can be obtained and the image quality is excellent. be effective.

Claims (1)

[Scope of Claims] 1. An organic photoreceptor having a photosensitive layer containing a hydrazone compound as a charge transport material, wherein the photosensitive layer contains a benzotriazole ultraviolet absorber. 2. The benzotriazole ultraviolet absorber is 2-(2-
hydroxy-3,5-di-tert-butylphenyl)
The organic photoreceptor according to claim 1, which is -5-chlorobenzotriazole. 3. The benzotriazole ultraviolet absorber is 2-(2-
The organic photoreceptor according to claim 1, which is hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole. 4. The organic photoreceptor according to claim 1, wherein the benzotriazole ultraviolet absorber is contained in an amount of 20 to 75 parts by weight based on 100 parts by weight of the hydrazone compound. 5. The organic photoreceptor according to claim 1, wherein the hydrazone compound is represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (In the formula, R^1 represents a hydrogen atom or a lower alkyl group) 6. The hydrazone compound is N-methyl-3-carbazolyl aldehyde N,N -Diphenylhydrazone.