JPH01136160A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high sensitivity and to lessen fluctuation of potential for repetitive electric charge or exposure of the photosensitive body even for an execution 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 formula I and also a linear sulfide structure expressed by formula II in a structural formula in a photosensitive layer. In formulas, each R1 and R2 is a (substituted)alkyl group, etc., or necessary residue for forming a 5- or 6-membered ring by combining R1 with R2; 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 small fluctuation of potential of the light zone and dark zone for repetitive electric charge or exposure for a long time during formation of a 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 including polyvinyl carbazole have been proposed as photoconductive materials for use in electrophotographic photoreceptors, but these polymers have poor film formability and poor film formability compared to inorganic photoconductive materials. Despite being superior in terms of lightness, it has been difficult to put it into practical use until now because sufficient film forming properties have not yet been achieved, and the sensitivity, durability, and environmental changes have made it difficult to put it into practical use. This is because they are inferior to inorganic photoconductive materials in terms of stability. In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat. Low molecular organic photoconductors have been proposed, such as the 9-styrylanthracene compounds described. Such low-molecular organic photoconductors are
By appropriately selecting the binder to be used, it has become possible to overcome the drawbacks in film formability that have been a problem in the field of organic photoconductive polymers, but this is not sufficient in terms of sensitivity.

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 in, for example, 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 (I) \ and a general formula (n) -3 -R3・・・・・・・・・・・・・・・・・・・・・
This is an electrophotographic photoreceptor characterized by containing a compound having a chain sulfide structure represented by (n) in a photosensitive layer.

In the formula, R1 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 Ro 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 represents an alkyl group such as methyl, propyl or butyl, or an aralkyl group such as benzyl, phenethyl or naphthylmethyl.

Furthermore, the groups represented by R1, R2, Ar and R3 may have a substituent, and examples of these substituents include methyl,
Alkyl groups such as ethyl and butyl, methoxy, ethoxy,
Alkoxy groups such as propoxy, benzyl, phenethyl,
Examples include aralkyl groups such as naphthylmethyl, halogen atoms such as fluorine, chlorine, bromine, and iodine, hydroxyl groups, and mercapto groups.

The compound of the present invention is constructed by bonding the above-mentioned disubstituted aminoaryl group and a sulfide 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 di-substituted aminoaryl group and the sulfide 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 d-orbital effect of the sulfur atom of the sulfide act synergistically against environmental deterioration factors generated inside copying machines, such as nitric acid, and prevent the penetration of environmental deterioration factors. considered to be a thing.

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

<Compound Examples> The compounds of the present invention can be synthesized by a general sulfide or tertiary amine synthesis method or a similar method, although the synthesis route differs depending on the structural formula.

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

Furthermore, many of the compounds of the present invention have carrier transport properties as charge transport substances by themselves. It may be used alone without being mixed with other charge transport materials 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-) Rinitro 9-fluorenone, 2. 4
．． 5.7-tetranitro-9-fluorenone, 2.4
．． 7-dolinitro 9-dicyanomethylenefluorenone, 2. 4. 5. 7-Titranitroxanthone, 2
, 4,8-trinidrothioxanthone and other electron-withdrawing substances, and polymerized products 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.

Hydrazones such as N-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, 1-(lepidyl (2)) -3-(p-diethylaminostyryl)-5
-(p-diethylaminophenyl)pyrazoline, l-[
Pyridyl(2))-3-(p-diethylaminostyryl)-4-methyl-5-(p-diethylaminophenyl)
Pyrazoline, i-(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,
Pyrazolines such as spiropyrazoline, α-phenyl-
4-N,N-diphenylaminostilbene, N-ethyl-3(α-phenylstyryl)carbazole, 9-p-
dibenzylaminobenzylidene-9H-fluorenone,
5-p-Ditolylaminobenzylidene-5H-dibenzo (a.

d] Styryl compounds such as cycloheptene, 2-(p
-diethylaminostyryl)-6-diethylaminobenzoxazole, 2-(p-diethylaminophenyl)
Oxazole compounds such as -4-(p-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole, bis(4 triarylmethane compounds such as -diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N);

N-diethylamino-2-methylphenyl)hebutane,
1. 1. 2. Polyarylalkanes such as 2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9- Examples include 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 sulfide structure in the above structural formula, which is dissolved in an appropriate solvent together with the above charge transport substance and binder. Apply a damp solution,
Preferably, it is formed by drying. 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-
Examples include butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, 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. In this case, this charge transport layer may be laminated on (or under) the charge generation layer. However, the charge transport layer may be laminated on the charge generation layer. It is desirable to be present.

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 impropatol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N+NL dimethylformamide toamide, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, and dioxane. , ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene, carbon tetrachloride,
Aliphatic halogenated hydrocarbons such as trichloroethylene, aromatics such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

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.

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

C2Hs 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 charge-generating substance described above in a suitable binder and coating it on a support, or by forming a vapor-deposited film using a vacuum evaporator. You can get it by doing this.

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,
Polyarylates (condensation polymers of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylpyrene, cellulose resin, urethane resin, epoxy resin, casein, Examples include insulating resins such as 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, ethylene glycol monomethyl ether, esters 1 such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene Aliphatic halogenated hydrocarbons such as ζ, carbon tetrachloride, trichloroethylene, etc., or aromatics such as benzene, toluene, 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
It is preferable to use a thin film layer having a thickness of m −=1 μm. This means that most of the incident light is absorbed by the charge generation layer, producing a large number of charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping (charge transport This is due to the need to inject into the layer.

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 in vacuum. Plastics having a layer formed by vapor deposition (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyethylene fluoride, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide,
Supports such as zinc oxide, carbon black, silver particles, etc.) coated on plastic or the above-mentioned conductive support with a suitable binder, supports made of plastic or paper impregnated with conductive particles, plastics containing conductive polymers, 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 topmost charge generation layer is set to be much thicker than the normal charge generation layer, mainly due to printing durability issues, and a charge transport substance is added to improve carrier transportability. There are many things. 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 A coating solution was prepared by dispersing 5 g of a disazo pigment represented by the following structural formula with a solution obtained by dissolving 2 g of butyral resin (degree of butyralization 70 mol%) in 100 ml of cyclohexanone in a sand mill for 24 hours. did.

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 structure shown below, 1.0 g of the above-mentioned exemplary compound Nα4, and 10 g of polycarbonate resin (average molecular weight 20,000) were dissolved in 70 g of monochlorobenzene, and this solution was spread over the previous charge generation layer with a Mayer bar. An electrophotographic photoreceptor having a laminated type photosensitive layer was manufactured by coating a charge transport layer with a dry film thickness of 20 μm.

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 20! ! It was exposed to UV light and its charging characteristics were investigated.

The charging characteristics include the surface potential (VO) and the amount of light exposure required to attenuate the potential (vl) when dark decaying for 1 second (
E'A) 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 (VD) were measured at the initial stage and after 50,000 copies were made.

In addition, the initial vo and vL are -700V and -200V, respectively.
It was set so that In addition, for comparison, a photoreceptor containing only a charge transporting substance without Exemplified Compound No. 4 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 15 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, in place of exemplified compound N014. Exemplary compound No. (
An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that 2) (18) (20) (21) (24) were added and a pigment having the following structure was used as a 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. All obtained good black images in the comparative examples, while there was a difference in intensity in the comparative examples. It has been found that the compound shown in FIG.

Examples 16 to 26 Pigments with the following structures were used as charge-generating substances, and exemplified compounds Nα(25) (27)(4) were used as charge-transporting substances.
2), an electrophotographic photoreceptor was produced in the same manner as in Example 1 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 has excellent characteristics in terms of sensitivity. Example 27 An ammonia aqueous solution of casein (11.2 g of casein, 28% ammonia water Ig,
22z and mj of water was applied by a blade coating method to form a subbing 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 (degree of butyralization: 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 0.15 μm.
A charge generation layer of m was formed.

Next, 10 g of the exemplified compound No. (36), polymethyl methacrylate resin (average molecular weight 50,000)
og was dissolved in 70 g of monochlorobenzene and applied onto 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 produced. The surface potential at this time was measured (initial potential Vo).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 1 second. The sensitivity is the exposure amount (8%, microjoule/c) required to attenuate the potential v1 after dark decay to %.
rtr). At this time, the light source was a gallium/aluminum→mu/arsenic ternary semiconductor laser (output 5 mw; oscillation wavelength 780 nm).
was used. These results were as follows.

Vo: 690V ■r: -675V Ey2: 1.4v x 1/cm"Next, the above was applied to a laser beam printer (LBP-CX manufactured by Canon), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser. The photoreceptor was replaced with an LBP-CX photoreceptor and set, and an actual image forming test was used.The conditions were as follows: -Surface potential knee 700V after next charging, surface potential after image exposure;- 150V (exposure amount 2.0 μJ/C) Transfer potential +700V, developer polarity: negative polarity, process speed: 50 mm/sec, development conditions (development bias): -450V, image exposure scan method: image scan, -order charging Pre-exposure; 50I!u
The entire surface of the X-8eC was exposed to red light and an image was formed 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 28 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate and poly(4,
4'-isopropylidene diphenylene carbonate) 3
g in 200ml of dichloromethane, then add 100ml of toluene! was added to precipitate the eutectic complex.

After filtering this precipitate, dichloromethane was added to redissolve it, and then 100 mji of n-hexane was added to this solution. was added to obtain a precipitate of a eutectic complex.

5 g of this eutectic complex was added to 95 ml of a methanol solution containing 2 g of polyvinyl butyral, and 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 coating 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 (32) was used.

The electrophotographic properties of the photoreceptor thus produced were measured in the same manner as in Example 2. The results are shown below.

Vo: -690V V,: -675V E%: 1.7 j! uxOsec first - Imperial Palace VD: -700V VL: -200V 10 000 mouth 'VD
: -665V VL : -235V [Effects of the Invention] As explained above, the electrophotographic photoreceptor containing the compound of the present invention has high sensitivity, and particularly in bright areas during continuous image formation by repeated charging and exposure over a long period of time. Since fluctuations in potential and dark area potential are small, a photoreceptor with excellent durability can be obtained. Further, the compounds according to the present invention include ozone and NOx.

White removal using nitric acid or the like is extremely effective against this phenomenon.

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 sulfide structure represented by the general formula (II) -S-R_3 (II). [In the formula, R_1 and R_2 represent an alkyl group, an aryl group, an aralkyl group, which may have a substituent, or a residue necessary to combine R_1 and R_2 to form a 5- to 6-membered ring, Ar represents an arylene group that may have a substituent, and R_3 represents an alkyl group or an aralkyl group that may have a substituent. ] (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.