JPH01136159A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high sensitivity and to lessen fluctuation of potential of an electrophotographic sensitive body for repetitive electric charge or exposure for a long time by incorporating a specified compd. into a photosensitive layer. CONSTITUTION:The title electrophotographic sensitive body contains a compd. having a disubstituted aminoaryl group expressed by the formula I and also a linear disulfide structure expressed by the formula II in the structural formula in a photosensitive layer. In the formulas, each R1 and R2 is a (substituted)alkyl group, etc., or R1 may combine with R2 forming a residue necessary for forming a 5- or 6-membered ring; Ar is a (substituted)arylene group; R3 is a (substituted) alkyl or (substituted)aralkyl group. By this constitution, an electrophotographic sensitive body having high sensitivity and high durability because of its lessened fluctuation of potential of light and dark zones for repetitive electric charge and exposure for a long time during formation of continuous picture image, is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a low molecular weight organic photoconductor that provides improved electrophotographic properties. be.

[Prior art]

Conventionally, various organic photoconductive polymers such as polyvinylcarbazole have been proposed as photoconductive materials for use in electrophotographic photoreceptors, but these polymers have poor film-forming properties compared to inorganic photoconductive materials. Although they are excellent in terms of light weight and other aspects, it has been difficult to put them into practical use until now because sufficient film formation properties have not yet been obtained, and sensitivity and
This is because they are inferior to inorganic photoconductive materials in terms of durability and stability against environmental changes. In addition, hydrazone compounds disclosed in US Pat. No. 4,150,987, etc.
Low-molecular organic photoconductive compounds such as triarylpyrazoline compounds described in U.S. Pat. body is proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

For these reasons, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed in recent years. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like. Such electrophotographic photoreceptors are disclosed, for example, in US Pat. No. 3,837,851 and US Pat. No. 3,871,882.

However, in electrophotographic photoreceptors that use conventional low-molecular-weight organic photoconductors in the charge transport layer, even if their sensitivity and characteristics have reached a practical level, the light area potential decreases when repeatedly charged and exposed. The drawback of large fluctuations in the dark potential has not been sufficiently resolved.

In order to suppress potential fluctuations during repeated use,
For example, JP-A-57-122444, JP-A-62-39
No. 863 discloses a method of mixing an antioxidant in a charge transport layer, and Japanese Patent Application Laid-Open No. 53-26128 discloses a method of mixing an antioxidant into a charge transport layer.
No., JP-A-60-164745, JP-A-62-105
According to No. 151, etc., a method of stabilizing by adding additives is known. However, the current situation is that these methods are not sufficiently effective, especially when repeatedly used over a long period of time.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages.

Another object of the present invention is to provide an organic photoconductor that is stable upon repeated use.

[Means for solving problems]

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, in which the structural formula includes a disubstituted aminoaryl group represented by the general formula (1) and a general formula (II
) -8-8-R3 Bends Between Bents This is an electrophotographic photoreceptor characterized by containing a compound having a chain disulfide structure shown in (II) in a photosensitive layer.

In the formula, R and R2 are methyl, ethyl, propyl,
Alkyl groups such as butyl, aryl groups such as phenyl, naphthyl, anthryl, biphenyl, aralkyl groups such as benzyl, phenethyl, naphthylmethyl, or R1 and R2
Combined with pyrrolidino.

Residues necessary to form a 5- to 6-membered cyclic amino group such as piperidino and morpholino are shown.

Ar is phenylene, naphthylene, or biphenylene.

Indicates an arylene group such as anthrylene.

R3 is an alkyl group such as methyl, ethyl, propyl, butyl, phenyl, naphthyl, anthryl.

Aryl groups such as biphenyl, or benzyl.

Indicates an aralkyl group such as phenethyl or naphthylmethyl.

Furthermore, the groups represented by RI T R21Ar and R3 may have a substituent, and examples of these substituents include alkyl groups such as methyl, ethyl, and butyl, alkoxy groups such as methoxy, ethoxy, and propoxy, and benzyl. , phenethyl, naphthylmethyl, and other aralkyl groups, fluorine, chlorine, bromine, iodine, and other halogen atoms, hydroxyl groups, and mercapto groups.

The compound of the present invention is constructed by bonding the above-mentioned disubstituted aminoaryl group and a chain disulfide structure, but the means of bonding is not specified.

In other words, excellent effects can be achieved even when two structural parts are directly bonded, whether they are bonded through a conjugated or non-conjugated organic group, or even when they are bonded in a way that shares an aryl moiety or the like. . In short, it is sufficient that the disubstituted aminoaryl group and the disulfide structure moiety coexist in the same molecule.

It is not clear why this structure has a uniquely good effect on characteristic deterioration due to repeated use, but it
The basicity of N in the di-substituted aminoaryl group and the disulfide
It is thought that the d-orbital effects of the sulfur atoms work synergistically to prevent the penetration of environmental deterioration factors.

Representative examples of the compounds of the present invention are listed below.

<Compound example> 9 ◇G N +CH2-3-5-CH2+G.

Zan 21"T5 8, 1 engineering, 0be) (XcH2-3-3% needle CH2→Although the synthesis route for the compound of the present invention differs depending on the structural formula, it can be synthesized using general disulfide, tertiary amine synthesis methods or similar methods. synthesized by law.

The compound of the present invention exhibits effects when incorporated into the charge generation layer or the charge transport layer of a layer-separated photosensitive layer in which a charge generation layer and a charge transport layer are laminated. shows a remarkable effect on

Moreover, many of the compounds of the present invention have carrier transport properties as charge transport substances by themselves, and may be used alone without being mixed with other charge transport substances as described below. The structure of the electrophotographic photoreceptor according to the present invention will be described in detail below.

Charge transporting substances used with the compound of the present invention include organic electron transporting substances and hole transporting substances.
Examples of electron transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane,
2,4.7-) dinitro-9-fluorenone, 2.4.
5.7-tetranitro-9-fluorenone, 2.4.7
-) dinitro-9-dicyanomethylenefluorenone,
2,4,5.7-titranitroxanthone, 2. 4.
Examples include electron-withdrawing substances such as 8-trinidrothioxanthone, and polymerization of these electron-withdrawing substances.

Examples of hole transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-Phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-10-ditylphenothia Zine, N, N-diphenylhydrazino-3-methylidene-10-ditylphenoxazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p
-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3. 3
-trimethylindolenine-ω-aldehyde-N,N-
Hydrazones such as diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazoline-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, l-phenyl-3- (p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl(
2))-3-(p-diethylaminostyryl)-5-(
p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline, 1-
[6-Medoxypyridyl(2))-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-(pyridyl(3))-3-(p-
diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-[lepidyl (2)]-3-
(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-[pyridyl (2))
-3-(p-diethylaminostyryl)-4-methyl-
5-(p-diethylaminophenyl)pyrazoline, 1-
(pyridyl(2))-3-(α-methyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, l-phenyl-3-(p-diethylaminostyryl)-4-methyl-5-( p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(α-benzyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, α-phenyl-4-N, N- diphenylaminostilbene, N-ethyl-3(α-phenylstyryl)carbazole, 9-p-dibenzylaminobenzylidene-9H-fluorenone, 5-p-ditolylaminobenzylidene-5H-dibenzo[a,d]cycloheptene, etc. Styryl compounds, 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole, 2-(p-diethylaminophenyl)-4-(p-
Oxazole compounds such as dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2-(p-
thiazole compounds such as diethylaminostyryl)-6-dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,
N-diethylamino-2-methylphenyl)hebutane,
1. 1.2.2-Tetrakis (4-N.

Polyarylalkanes such as N-dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-
Examples include N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole formaldehyde resin.

These charge transport substances can be used alone or in combination of two or more.

The charge transport layer in the layer-separated electrophotographic photoreceptor according to the present invention includes a compound having both a disubstituted aminoaryl group and a disulfide structure in the above structural formula, which is dissolved in an appropriate solvent together with the charge transport substance and the binder. It is preferable to form it by applying a diluted solution and drying it.

As mentioned above, when the compound of the present invention has a function as a charge transport substance, it may be used simply together with a binder.

Examples of the binder used here include polyarylate resin, polysulfone resin, polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, and polycarbonate. , polyurethane or copolymer resins such as styrene-
Mention may be made of butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, and the like. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene, and polyvinylpyrene can also be used.

The blending ratio of the binder and the charge transport material is 10 parts of the binder.
Preferably, the amount of charge transport material is 10 to 500 parts by weight per 0 parts by weight.

The charge transport layer is electrically connected to the charge generation layer below and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, it is desirable that the charge transport layer is laminated on the charge generation layer.

Since this charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary.

Generally, it is 5 μm to 40 μm, but the preferred range is 10 μm to 30 μm.

The organic solvent used when forming such a charge transport layer is
The binder varies depending on the type of binder used, and it is preferable to select one that does not dissolve the charge generation layer or underlying subbing layer. Specific organic solvents include alcohols such as methanol, ethanol, and impropatul, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and nitrogen.

Amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, and methylene chloride. , aliphatic halogenated hydrocarbons such as dichloroethylene, carbon tetrachloride, and trichlorethylene, or aromatics such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene.

Coating can be carried out using a coating method such as a dip coating method, a spray coating method, a Meyer bar coating method, or a blade coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying is generally preferably carried out at a temperature of 30° C. to 200° C. for a period of 5 minutes to 2 hours, either stationary or with ventilation.

The charge transport layer can also contain various additives. Examples include plasticizers such as diphenyl, m-terphenyl, and dibutyl phthalate, surface lubricants such as silicone oil, grafted silicone polymers, and various fluorocarbons.

The charge generation layer used in the present invention is made of inorganic charge generation substances such as selenium, selenium-tellurium, amorphous silicon, pyrylium dyes, thiapyrylium dyes, azulenium dyes, thiacyanine dyes, quinocyanine dyes, azulenium dyes, etc. Organic charge generation such as cationic dyes, squbarium salt dyes, phthalocyanine pigments, anthorone pigments, dibenzpyrenequinone pigments, polycyclic quinone pigments such as pyranthrone pigments, indigo pigments, quinacridone pigments, azo pigments, etc. Materials selected from among the substances can be used alone or in combination as a vapor deposited layer or a coating layer.

Among the charge-generating substances used in the present invention, there are a wide variety of azo pigments in particular, and typical structural examples of particularly effective azo pigments are shown below.

The general formula of an azo pigment is as shown below, with the central skeleton being A.

AmoN=N-Cp) n If we express part of the coupler as Cp (here n=2゜0
r3), first, specific examples of A include the following.

C2H5 Also, specific examples of Cp include (R: alkyl, aryl, etc.). The central skeleton A and the coupler Cp form a pigment serving as a charge-generating substance by appropriate combination.

The charge-generating layer can be formed by dispersing the above-mentioned charge-generating substance in a suitable binder and coating it on a support, or can be obtained by forming a vapor-deposited film using a vacuum evaporation device. Can be done. The binder can be selected from a wide range of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate,
Acrylic resin, polyacrylamide resin, polyamide,
Examples include insulating resins such as polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less. Examples of organic solvents used during coating include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and N,N-dimethylformamide.

Amides such as N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene, Aliphatic halogenated hydrocarbons such as carbon tetrachloride and trichlorethylene, benzene, toluene,
Aromatics such as xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating can be performed using the coating method described above.

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and in order to inject carriers into the charge transport layer within the lifetime of the generated charge carriers, a thin film layer, e.g. 5 μm or less, preferably 0.01 μm
A thin film layer having a thickness of m-1 μm is preferable.

This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping (the charge transport layer This is due to the need to inject.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a conductive support.

As the conductive support, materials that have conductivity themselves, such as aluminum, aluminum alloy, stainless steel, nickel, and indium, can be used.In addition, aluminum, aluminum alloy, indium oxide, tin oxide, etc. can be used. Plastics with a layer formed by vacuum deposition (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyethylene fluoride, etc.)
, conductive particles (e.g. aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.)
A support obtained by coating a plastic or the above-mentioned conductive support with a suitable binder, a support obtained by impregnating plastic or paper with conductive particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The subbing layer can be formed from casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane, gelatin, aluminum oxide, or the like.

The thickness of the undercoat layer is 0.1 μm to 5 μm, preferably 0.1 μm to 5 μm.
A suitable thickness is 5 μm to 3 μm.

When using a photoreceptor in which a conductive support, a charge generation layer, and a charge transport layer are laminated in this order, if the charge transport material has hole transport properties, the surface of the charge transport layer must be negatively charged; When exposed to light after being charged, holes generated in the charge generation layer in the exposed area are injected into the charge transport layer, and then reach the surface and neutralize the negative charge, resulting in attenuation of the surface potential and the generation of static electricity between the exposed area and the unexposed area. Contrast occurs. During development, it is necessary to use positively charged toner.

On the other hand, when the charge transport material has electron transport properties, it is necessary to charge it positively and the developing toner to charge it negatively. When a photoreceptor in which the charge transport material has a hole transport property and a conductive support, a charge transport layer, and a charge generation layer are laminated in this order is used, the charge will be negative, and the developing toner will be positive.

In this case, the top charge generation layer is set to be considerably thicker than a normal charge generation layer mainly due to printing durability issues, and a charge transport material is added to improve carrier transportability. There are many things to add. In this case as well, the compounds according to the invention can be used as charge transport substances or as additives for stabilizing the potential properties of charge transport substances.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It can also be widely used in electrophotographic application fields such as electrophotographic plate making systems.

According to the present invention, it is possible to provide an electrophotographic photoreceptor that is highly sensitive and exhibits little potential fluctuation even after repeated charging and exposure over a long period of time.

Hereinafter, the present invention will be explained according to examples.

Example 1 and Comparative Example 1 5 g of a disazo pigment represented by the following structural formula was mixed with 2 g of butyral resin (degree of butyralization 70 mol%) and 100 mI of cyclohexanone! 24 hours in a sand mill with the solution dissolved in
A coating solution was prepared by dispersing the mixture over time.

This coating solution was applied onto an aluminum sheet using a Mayer bar to a dry film thickness of 0.2 μm to form a charge generation layer.

Next, as a charge transport material, 10 g of hydrazone having the following structure and the exemplified compound Nα2 1. Dissolve Og and 10 g of polycarbonate resin (average molecular fi 20,000) in 70 g of monochlorobenzene, and apply this solution onto the charge generation layer using a Mayer bar to form a charge transport layer with a dry film thickness of 20 μm. An electrophotographic photoreceptor having layers was manufactured.

The electrophotographic photoreceptor manufactured in this way was sold to Kawaguchi Electric Co., Ltd.
Electrostatic copying paper tester Model-3P-428 was used to statically charge the corona at 15 KV, and the test was carried out in the dark at 1
After holding for a second, the illuminance is 201! It was exposed to UV light and its charging characteristics were examined.

The charging characteristics include the amount of light exposure required to attenuate the surface potential (VO) and the potential (Vl) after 1 second of dark decay (
8%) was measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, the photoreceptor prepared in this example was attached to the photosensitive drum cylinder of a PPC copier NP-3525 manufactured by Canon Inc. , 50,000 copies were made using the same machine, and changes in bright area potential (VL) and dark area potential (Vo) were measured at the initial stage and after 50,000 copies were made.

In addition, the initial v. and vL were set to -700V and -200V, respectively. Further, for comparison, a photoreceptor containing only a charge transport material without the exemplified compound Nα2 was manufactured, and measurements were conducted in the same manner.

The results are shown in Table 1.

Table 1 From Table 1, it is clear that when the compounds of the present invention are used, good sensitivity is maintained and potential fluctuations during durability are small. Further, when images were printed after 50,000 sheets under the same conditions as the initial condition, there was almost no change in the images in the examples, but the images in the comparative examples had a lot of blurring.

Examples 2 to 11 and Comparative Examples 2 to 8 In each of these Examples, a compound having a 7-membered ring having the following structure was used in place of the charge transport substance used in Example 1, and further, exemplified compound (2) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that exemplified compound Nα(1) was added instead and a pigment having the structure shown below was used as the charge generating substance.

The electrophotographic characteristics of each photoreceptor were measured in the same manner as in Example 1, except that the durability characteristics were changed to 10,000 sheets.

The results are shown in Table 2 below. Further, as a comparative example, similar measurements were performed on photoreceptors in which the compound of the present invention was not added, and furthermore, various compounds other than the present invention were added, and the results are shown in Table 3.

As is clear from Tables 2 and 3, when the compounds of the present invention are used, better sensitivity is maintained compared to conventional ones, and potential fluctuations during durability are also small.

Further, after conducting an image reproduction test using the above-mentioned copying machine NP-3525, the black paper was copied by leaving it as it was until the next morning. In all cases, good black images were obtained, whereas in the comparative examples, although there were differences in intensity, the so-called white spot phenomenon occurred in which the portion facing the charger appeared white without exception. From this, it can be seen that the compound of the present invention is extremely effective against ozone, NOx, nitric acid, etc. formed in a copying machine, particularly in a charger.

Examples 12 to 16 Shadow ≠ Poison Coral Dark Pigments with the following structures were used as charge-generating substances, and example compounds Ni1 (13) (14) were used as charge-transporting substances.
An electrophotographic photoreceptor was produced in the same manner as in Example 1 using (16), (18), and (20) without adding any additives.

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. The results are shown in Table 4.

The compound of the present invention not only contributes to potential stability but also exhibits excellent characteristics in terms of sensitivity. 28% ammonia water Ig
, water 222mj? ) was applied using a blade coating method to form an undercoat layer with a dry film thickness of 1 μm.

Next, 10 g of a charge generating substance represented by the following structural formula.

5 g of butyral resin (butyralization degree: 63 mol%) and 200 g of cyclohexanone were dispersed for 48 hours using a ball mill disperser. This dispersion was applied onto the previously prepared undercoat layer using a blade coating method, and the dry film thickness was 0.
A charge generation layer of 15 μm was formed.

Next, the exemplified compound No. (12) Log, polymethyl methacrylate resin (average molecular 1150,000) 1
0 g was dissolved in 70 g of monochlorobenzene and coated on the previously formed charge generation layer by a blade coating method to form a charge transport layer with a dry film thickness of 19 μm.

A corona discharge of 15 KV was applied to the photoreceptor thus manufactured. The surface potential at this time was measured (initial potential V).
. Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 1 second. Sensitivity was evaluated by measuring the amount of exposure required to attenuate the potential v1 in sweat after dark decay (A s microjoules/crtr). At this time, the light source was a gallium/aluminum/propylene ternary semiconductor laser (output: 5 mw; oscillation wavelength: 780 mw).
nm) was used. These results were as follows.

V, : -690V V, : -680V 8% = 1.3 microjoules/cm2 Next, a laser beam printer (LBP-CX manufactured by Canon), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser as above. The above photoreceptor was replaced with an LBP-CX photoreceptor, and an actual image forming test was conducted. The conditions are as follows. −Surface potential after next charging,
-700V, surface potential after image exposure; -150V (exposure amount 2.0 μJ/crrr) transfer potential +700V
, developer polarity; negative polarity, process speed; 50mm
/see, development conditions (development bias); -450V
, image exposure scanning method; image scanning, -exposure before next charging; 501! UX-sec red full-surface exposure and image formation were performed by line scanning a laser beam in accordance with character and image signals, and good prints were obtained for both characters and images. Furthermore, when 30,000 images were printed continuously, stable and good prints were obtained from the initial stage up to 30,000 sheets.

Example 18 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate and poly(4,4
'-isopropylidene diphenylene carbonate) 3g
was sufficiently dissolved in 200 mf of dichloromethane, then 100 mj of toluene! was added to precipitate the eutectic complex. After filtering off this precipitate, dichloromethane was added to redissolve it, and then 100 rrl of n-hexane was added to this solution to obtain a precipitate of a eutectic complex.

95mf of a methanol solution containing 5g of this eutectic complex and 2g of polyvinyl butyral! In addition, the mixture was dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum plate having a casein layer using a Mayer bar so that the film thickness after drying was 0.4 μm to form a charge generation layer.

Next, a cover layer of a charge transport layer was formed on this charge generation layer in exactly the same manner as in Example 1 except that exemplified compound (19) was used.

The electrophotographic properties of the photoreceptor thus produced were measured in the same manner as in Example 1. The results are shown below.

V, : -690V V, : -675V EH: 1.6j! ux*sec Side--Dish VD: -700V VL knee 200V 10 000 Mouth' VD: -675V VL: -230V [Effects of the Invention] As explained above, the electrophotographic photoreceptor containing the compound of the present invention has a high It provides a photoreceptor with excellent durability because of its sensitivity and small fluctuations in bright area potential and dark area potential especially during continuous image formation by repeated charging and exposure over a long period of time.

Furthermore, the compound of the present invention is extremely effective against white removal phenomena caused by ozone, NOx, nitric acid, and the like.

Claims (3)

[Claims] (1) In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, the structural formula includes general formula (I) ▲Mathematical formula, chemical formula, table, etc.▼……(I) Disubstitution An electrophotographic photoreceptor characterized in that a photosensitive layer contains a compound having both an aminoaryl group and a chain disulfide structure represented by the general formula (II) -S-S-R_3 (II) . [In the formula, R_1 and R_2 are an alkyl group, an aryl group, an aralkyl group, which may have a substituent, or R_1
represents a residue necessary to form a 5- to 6-membered ring by bonding with R_2, Ar represents an arylene group that may have a substituent, and R_3 represents an alkyl group that may have a substituent. ,
Indicates an aryl group or an aralkyl group. ] (2) The electrophotographic photoreceptor according to claim 1, wherein the compound is used as a charge transport material contained in the photosensitive layer. (3) The electrophotographic photoreceptor according to claim 1, wherein the compound is used as an additive to a charge transport substance contained in the photosensitive layer.