JPH0232358A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and to decrease the fluctuation in bright part potential and dark part potential at the time of repetitive electrostatic charge and exposing by incorporating a specific compd. into a photosensitive layer. CONSTITUTION:The compd. expressed by formula I is incorporated into the photosensitive layer of the electrophotographic sensitive body formed by laminating the photosensitive layer on a conductive base. In formula I, R1, R2 denote an alkyl group, aryl group or aralkyl group; R3 denotes a hydrogen atom, alkyl group, aryl group, aralkyl group or -SR7 group (R7 denotes an alkyl group, aryl group or aralkyl group). R4-R6 denote a hydrogen atom, alkyl group, aryl group, aralkyl group, halogen atom or -SR7 group; x denotes an ethylene group, vinylene group, oxygen atom, amino group (=N-R8) or sulfur atom; R8 denotes an alkyl group, aryl group or aralkyl group. The high sensitivity is obtd. in this way and the fluctuation in the bright part potential and dark part potential is decreased at the time of the repetitive electrostatic charge and exposing. The durability is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors containing low molecular weight organic photoconductors that provide improved electrophotographic properties.

[Prior Art] Various organic photoconductive polymers, including polyvinylcarbazole, have been proposed as photoconductive materials for use in electrophotographic photoreceptors, but these polymers have a disadvantage in comparison to inorganic photoconductive materials. Although it has excellent film formability and light weight, it has been difficult to put it into practical use until now because sufficient film formability has 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, pidrazone compounds disclosed in US Pat. No. 4,150,987, triarylpyrazoline compounds described in US Pat. No. 3,837,851, etc.,
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in JP-A-94828 and JP-A-51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that have been a problem in the field of organic photoconductive polyamides. , cannot be said to be sufficient in terms of sensitivity.

For this reason, in recent years, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed. 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 an electrophotographic photoreceptor is disclosed in, for example, Japanese Patent Application Laid-open No. 58-19
There are laminated materials of an azo compound and a styryl compound disclosed in JP-A No. 8043, JP-A-54-110837, JP-A-55-161247, and the like.

However, electrophotographic photoreceptors that use conventional low-molecular organic photoconductors in the charge transport layer do not necessarily have sufficient sensitivity and characteristics, and when repeatedly charged and exposed, the bright area potential and dark area potential change. There are areas that need improvement.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages, to provide a novel organic photoconductor, and to provide a charge generation layer and a charge transport layer. The object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer with functionally separated functions.

[Means for Solving the Problems, Effects] The present invention is an electrophotographic photoreceptor comprising a photosensitive layer laminated on a conductive support, characterized in that the photosensitive layer contains a compound represented by the following general formula (1). Consists of an electrophotographic photoreceptor.

r R (wherein R1 and R2 represent an alkyl group, an aryl group, or an aralkyl group that may have a substituent, and may be the same or different.

R3 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a -SR7 group which may have a substituent (R7 represents an alkyl group, an aryl group, or an aralkyl group).

R4, R5 and R6 represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group, a halogen atom or a -SR7 group, and may be the same or different.

However, when R,, R2 has a substituent, at least one of R3, R4, Rs, R6 is -SR
7 groups, and when there are two or more -SR7 groups, R7 may not be the same.

X is an ethylene group, a vinylene group, an oxygen atom, an amine 7 group (=
N-R8) or a sulfur atom, R8 is an alkyl group,
Indicates an aryl group or an aralkyl group.

Specifically, in R1 and R2, alkyl groups include methyl, ethyl, propyl, butyl, etc., aryl groups include phenyl, naphthyl, etc., and aralkyl groups include benzyl, naphthylmethyl, etc. Furthermore, substituents for the above groups include halogen atoms such as fluorine atom, chlorine atom, iodine atom, and bromine atom, alkyl groups such as methyl, ethyl, propyl, and butyl, and alkoxy groups such as methoxy, ethoxy, and phenoxy.
Examples of R7 include groups such as methyl, ethyl, propyl, butyl, phenyl, naphthyl, and benzylnaphthylmethyl.

Also in the case of R3, R4, R5, and Re, the same groups as R1 can be specifically mentioned.

Also, R8 in the case of, Specifically R7 A group similar to Compound example (5) can be mentioned.

Below is the general formula (1) Representative compounds shown in List examples.

Compound example (1) Compound example (6) Compound example (2) Compound example (7) Compound example (3) Compound example Compound example Compound example Compound example (1 Compound example (10) l Compound example (15) C look Compound example (11) Compound example (1 Compound example (12) Compound example (17) SC,H.

Compound example (13) Compound example (18) SC Yu Hri eye Compound example (19) Compound example (20) Compound example (21) Compound example (22) n-C Gin89 Compound example (23) Compound example (28) Compound example (29) Compound example (30) Compound example (31) Compound example (32) Compound example (24) Compound example (25) Compound example (26) Compound example (27) Compound example (33) Compound example (34) Compound example (35) Compound example (36) Compound example (37) Compound example (38) Compound example (39) Compound example (40) Compound example (41) Compound example (47) Synthesis example (Compound example Synthesis of (18)) (II) (m) (IV) (V) (Vl) Compound example (42) Compound example (43) Compound example (44) l Compound example (45) Compound example (46) (■) Above formula benzyl chloride de Wittig reagent from (m) west.

Nitration (IV) After that, dibenzos React with berenone, nitro body (V) year, Zara reduced to amino form (Vl) I got it.

This and 4- (Methyl mercapto) With aniline Perform the Le Mans reaction, Target compound (■) I got it.

Yield, 1% Melting point 2°C Elemental analysis 3e S2 M W : Measured value (%) Theoretical value (%) H5,515,42 N 2.52 2.60S
11.80 11.88 Compounds other than those on the synthesis side are generally synthesized using the same method.

In a preferred embodiment of the present invention, the compound represented by the general formula (I) is used as a charge transporting material in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer in the present invention is preferably formed by applying a solution of the compound represented by the general formula (I) and a binder dissolved in an appropriate solvent and drying the solution.

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

The blending ratio of this binder and the specific charge transport substance is
Charge transport material per 100 parts by weight of binder: lO~'500
Preferably, it is expressed in parts by weight.

The charge transport layer is electrically connected to the charge generation layer described 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. are doing. At this time, this charge transport layer may be laminated on the charge generation layer, and fI! However, it is preferred that the charge transport layer is laminated on top of the charge generation layer.

This charge transport layer has a limit to its ability to transport charge carriers, so it cannot be made thicker than necessary. Generally, the thickness is 5 to 40 gm, but the preferred range is 10 to 40 gm.
It is 30gm.

The organic solvent used in forming such a charge transport layer varies depending on the type of binder used, and is preferably selected from those that do not dissolve the charge generation layer or the subbing layer described below.

Specific organic solvents include methanol, ethanol,
Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, N
, amides such as N-dimethylformamide and NN-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, methylene chloride, and dichloride. Aliphatic halogenated hydrocarbons such as ethylene, carbon tetrachloride, and trichloroethylene, and aromatics such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene can be used.

Coating methods include dip coating method, spray kneading method, spinner coating method, bead coating method,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. Drying is preferably carried out by drying to the touch at room temperature, followed by heat drying. Heat drying is generally preferably carried out at a temperature of 30 to 200°C for 5 minutes to 2 hours, either stationary or under ventilation. .

The charge transport layer of the present invention may contain various additives, such as plasticizers such as diphenyl, m-terphenyl, and dibutyl phthalate, silicone oil, grafted silicone polymers, and various fluorocarbons. Examples include surface warming lubricants, dicyanovinyl compounds, potential stabilizers such as carbazole derivatives, and antioxidants such as β-carotene, Ni complexes, and 1,4-diazabicyclo[2,2,2]octane.

The charge generation layer in the present invention includes an inorganic charge generation substance such as selenium, selenium-tellurium, amorphous silicone, etc.
Cationic dyes such as biryllium dyes, thiapyrylium dyes, azulenium dyes, thiacyanine dyes, and quinocyanine dyes, squbarium salt dyes, phthalocyanine pigments and anthrone pigments, dibenzpyrenequinone pigments, vilanthrone pigments, etc. Materials selected from organic charge-generating substances such as non-cyclic pigments, indigo pigments, quinacridone pigments, and azo pigments can be used alone or in combination as a vapor deposited layer or a coating layer.

Among the above-mentioned charge-generating substances, there are a wide variety of azo pigments in particular, and typical structural examples of particularly effective azo pigments will be described below.

The general formula of the azo pigment is shown below, with the central skeleton being A and the coupler portion being Cp, where n is 1 or 2. Specific examples are given below.

A (N=N-Op) n Specific examples of A include (R: hydrogen atom, chlorine atom, methoxy group) -o-CH-C-@- (R: hydrogen atom, cyan group) (R: hydrogen atom, cyano group) methyl group, chlorine atom) (X: oxygen atom, sulfur atom R,, R2: hydrogen atom, methyl group, chlorine atom) (Rz: hydrogen atom, methyl group, chlorine atom, etc. °C): hydrogen atom , methyl group, A-1446B) (x: oxygen atom, sulfur atom) (x: oxygen atom, sulfur atom) (X: oxygen atom.

sulfur atom) (x: (X oxygen atom, oxygen atom, sulfur atom) sulfur atom) C engineering HE No. CM-N-N-CH building (R: (X hydrogen atom, methyl group) 40) I-engineering; oxygen atom, sulfur atom.

1lSO:L) A-21+N-@- (R: hydrogen atom, methyl group) Specific examples of Cp include (R: hydrogen atom, halogen atom, alkoxy group, alkyl group, nitro group, etc. n: 1 or 2 ) (R: methyl group, ethyl group, propyl group, etc.) (R: alkyl group, aryl group, etc.) R' child, halogen atom, alkoxy group, alkyl group, nitro group, etc.)] Kλ (R1, R2: hydrogen atom , halogen atom alkoxy group,
Examples include an alkyl group, a nitro group, etc. (n: 1 or 2).

The central skeleton A and the coupler Cp form a pigment serving as a charge-generating substance by appropriate combination.

The charge generation layer can be formed by dispersing the charge generation substance described above in a suitable binder and coating it on a support, or by forming a vapor deposited film using a vacuum evaporation device. .

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 (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol,
Examples include polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

Organic solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N,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, and aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Halogenated hydrocarbons or aromatics such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. Drying is preferably carried out by drying to the touch at room temperature, followed by heat drying. Heat drying is generally preferably carried out at a temperature of 30 to 200°C for 5 minutes to 2 hours, either stationary or under ventilation. .

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and contains a thin film layer, e.g. 5pm or less, preferably 0.001
It is desirable to form a thin +1!2 layer with a film thickness of -1p.

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 injected into the charge transport layer without being deactivated by recombination or trapping. This is due to the need to do so.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a support having a conductive layer. As the support having a conductive layer, the support itself is conductive, such as aluminum, aluminum alloy, copper,
Zinc, stainless steel, vanadium, molybdenum, chromium,
Plastics that can use titanium, nickel, indium, gold, platinum, etc., and have a layer formed by vacuum evaporation of aluminum, aluminum alloys, indium oxide, tin oxide, indium oxide-tin oxide alloys, etc. For example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate,
acrylic resin, polyfluoroethylene, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) are coated on the plastic or the aforementioned conductive support together with a suitable binder. The support may be a support made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, or the like.

Guide II! A subbing layer having barrier and adhesive functions can also be provided between the layer and the photosensitive layer.

The subbing layer can be formed from casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin aluminum oxide, etc. .

The thickness of the subbing layer is 0.1 to 5 gm, preferably 0.5 to 3 gm.
＼m is appropriate.

When using a photoreceptor in which a conductive support, a charge generation layer, and a charge transport layer are laminated in this order, the charge transport compound in the present invention has hole transport properties, so it is necessary to negatively charge the surface of the charge transport layer. Yes, Obi'F! During post-exposure, 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 charges, 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.

In another embodiment of the invention, the aforementioned disazo pigments or the disazo pigments described in U.S. Pat.
The photoconductivity of pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, benzopyrylium dyes, benzothiapyryllium dyes, naphthopyryllium dyes, naphthothiapyrylium dyes, etc. disclosed in Specification No. 8, Specification No. 3586500, etc. Pigments and dyes can also be used as sensitizers.

In another specific example, a eutectic complex of a pyrylium dye and an electrically insulating polymer having an alkylidene diarylene moiety, such as disclosed in US Pat. No. 3,684,502, can be used as a sensitizer. This eutectic complex is, for example, 4-[4-bis(2-chloroethyl)aminophenyl]
-2,6-cyphenylthiavirylium perchlorate and poly(4,4'-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent such as dichloromethane, chloroform, carbon tetrachloride, 1°1-dichloroethane, 1.2-dichloroethane, 1.1.2-1 dichloroethane, chlorobenzenebromobenzene, 1.2
- After dissolving in dichlorobenzene etc., add a non-polar solvent such as hexane, octane, decane, 2,2.4-
It is obtained as a particulate eutectic complex by adding trimethylbenzene, ligroin, etc.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-7-acrylonitrile copolymer vinyl acetate-vinyl chloride copolymer polyvinyl butyral, polymethyl methacrylate, poly- N-butyl methacrylate, polyesters, cellulose esters, etc. can be contained as a binder.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in a wide range of electrophotographic applications such as laser beam printers, CRT printers, and electrophotographic plate making systems.

The electrophotographic photoreceptor of the present invention has the advantage of high sensitivity and small fluctuations in bright area potential and dark area potential when repeatedly charged and exposed.

[Example] Example 1 5 g of a disazo pigment represented by the following structural formula was mixed with butyral resin (
Butyralization degree: 63 mol%) 2g of scrohexanone
A coating solution was prepared by dispersing the solution in a sand mill for 24 hours together with the solution dissolved in 0.00ml.

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

Next, 10 g of Compound Example (7) as a charge transport material and 10 g of polycarbonate (average molecular weight 20,000) were dissolved in 70 g of chlorobenzene, and this solution was applied onto the charge generation layer using a Mayer bar, and the dried film was coated. A charge transport layer having a thickness of 20 pm was formed to produce an electrophotographic photoreceptor.

The electrophotographic photoreceptor thus prepared was corona-charged at 5 KV in a static mode using an electrostatic copying paper tester Model-3P-428 manufactured by Kawaguchi Denki, held in a dark place for 1 second, and then exposed to light at an illuminance of 20 lux. , the charging characteristics were investigated.

As for charging characteristics, the surface potential (vO) and the exposure amount (E 1/2) required to attenuate the potential (vl) to 1/2 when dark decayed for 1 second were measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, the electrophotographic photoreceptor prepared in this example was attached to a photosensitive drum cylinder of Canon PPC Duplicator NP-3525. , 5,000 sheets with the same machine
Copying is performed, and the bright area potential (initial and after 5,000 copies) is
Variations in VL) and dark potential (Vo) were measured.

In addition, initially 0) Vo and VL are each h-700V, 20
It was set to 0v.

Example 1 -690 -685 1.4V5
V Example I Vo -700-695L Examples 2 to 14 In each of these Examples, instead of the charge transport compound example (7) used in Example 1, compound examples (1), (4), and (14) were used.
), (18), (21), (27), (29), (31
), (33).

An electrophotographic photoreceptor was prepared using (38), (40), (44), and (47), and a pigment having the structural formula below as a charge generating substance, with the other conditions being the same as in Example 1. .

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. The results will be described later.

Comparative Examples 1 to 3 For comparison, electrophotographic photoreceptors were prepared in the same manner as in Example 2 except that a compound having the following structure was used as a charge transport material, and the electrophotographic properties were measured in the same manner. The results will be described later.

Comparative compound example (1) (JP-A-58-198043) Comparative compound example (2) (JP-A-54-110837) 1.5 1.0 2.9 2.7 2.0 2.6 1.7 2 , 8 2.3 Comparative compound example (3) (JP-A-55-161247) (1) 690 680 3.4 (2)
695 685 4.7 (3) 695
670 4.31.8 1.2 1.8 1,0 Sensitivity is improved compared to the electrophotographic photoreceptor of the comparative example after initial 5,000-sheet durability.
In addition, potential fluctuations due to use of edge-turning are extremely small, and stability is particularly excellent.

Example 15 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 22.2 mfL of water) was applied onto an aluminum sill by a blade coating method,
A subbing layer with a dry film thickness of 1 pm was formed.

Next, based on the charge generating substance Log shown by the following structural formula and the above results after initial durability of 5,000 sheets, the electrophotographic photoreceptor of the present invention has the general formula (
By using the compound shown in I), 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 formed subbing layer by a blade coating method to form a charge generation layer with a dry film thickness of 0.15 pm.

Next, 10 g of compound example (16) and 70 g of polymethyl methacrylate (average molecular weight 50,000) log of chlorobenzene were added.
g and applied by blade coating onto the previously formed charge generation layer to form a charge transport layer with a dry film thickness of 19 μm.

A corona discharge of 15 KV was applied to the electrophotographic photoreceptor thus prepared. The surface potential at this time was measured (initial potential Vo), and the surface potential after this photoreceptor was left in a dark place for 1 second was measured.

Sensitivity is the exposure amount (El/2, microjoule/cm2) required to attenuate the potential v1 after dark decay to 1/2.
It was evaluated by measuring.

At this time, the light source was a gallium/aluminum/arsenic ternary semiconductor laser (output: 5 mw, oscillation wavelength: 780 nm).
m) was used. Show the results.

vo knee 695V vt knee 685VEl
/2: 1.3 microjoules/crn 2nd, a laser beam printer (a reversal development type electrophotographic printer equipped with the same semiconductor laser as above) (
Canon Co., Ltd., LBP-CX) with the above photoreceptor LBP-
An actual image forming test was conducted by setting the photoreceptor in place of the CX photoreceptor.

The conditions were: surface potential knee 700 V after negative charging, surface potential knee 150 V after image exposure (exposure amount 2.0 microjoules/cm2), transfer potential: +700 V, developer polarity: negative polarity, process speed: 50 mm. /sec, development conditions (development bias) knee 450V, image exposure scan method:
Image scan, - exposure before next charging: 50 sentences ux, se
The entire red exposure and image formation in c were carried out by line scanning a laser beam in accordance with character and image signals, and good prints were obtained for both characters and images. Further, when 3,000 images were printed continuously, stable and good prints were obtained from the initial stage up to 3,000 sheets.

Example 16 3 g of 4-(4-dimethylaminophecol)-2,6-cyphenylthiavirylium perchlorate and compound example (
11) was mixed with 100 m of a toluene (50 parts by weight)-dioxane (50 parts by weight) solution of polyester (Polyester Adhesive 49000, manufactured by DuPont) and dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 Bm.

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

vo knee 700V V, knee 695Vel/2:
1.51ux, sec Hatsu-Ichitomo Vo Knee 695V VL Knee 85V Dango” Missing 1
” (VOL Knee 690V VL Knee 95V Example 17 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiavirylium perchlorate and poly(4,
4'-isopropylidene diphenylene carbonate) 3
After sufficiently dissolving 1.g in 200 ml of dichloromethane, toluene was added to precipitate the eutectic complex. After filtering this precipitate, dichloromethane was added to redissolve it, and then 100 mL of n-hexane was added to this solution to obtain a precipitate of a eutectic complex.

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

Next, a cover layer of a charge transport layer was formed in the same manner as in Example 1 except that Compound Example (36) was used on the charge generation layer.

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

vo knee 700V Vl knee 680Vel
/2: 2.31ux, see Prayer 8 Vo Knee 695V VL Knee 105V Dan' Yo Nine Drops [猜VD Knee 680V VL Knee 120V Example 18 Aqueous ammonia solution of casein (described above) was put on a Mayer par on an aluminum plate. to form an undercoat layer having a dry film thickness of lpm. The charge transport layer and charge generation layer of Example 5 were successively layered thereon, and an electrophotographic photoreceptor was prepared in exactly the same manner as in Example 5, except that the layer structure was different, and charged in the same manner as in Example 5. Characteristics were measured. However, the charging polarity was set to 10. Show the results.

vo: +695V Vl: +690VE
l/2: l, 31ux, see Example 19 Soluble nylon (6-66-610-12
Apply a 5% solution of metatsuru (quaternary nylon copolymer),
A subbing layer having a dry thickness of 0.5 gm was formed.

Next, 5 g of the pigment having the following structural formula was added to 95 g of tetrahydrofuran.
The mixture was dispersed in a sand mill for 200 hours using a sand mill disperser.

Next, a solution prepared by dissolving 5 g of Compound Example (20) and 10 g of bisphenol z5 polycarbonate (viscosity average molecular weight: 30,000) in 30 mL of chlorobenzene was added to the dispersion prepared above, and the mixture was further dispersed for 2 hours using a sand mill. This dispersion was applied onto the previously formed subbing layer using a Mayer bar so that the film thickness after drying would be 20 gm, and then dried.

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

Vo knee 685V Vl knee 665Vel
/2: 2.31 ux, sec [Effect of the invention] The electrophotographic photoreceptor containing the specific sulfide compound of the present invention has high sensitivity, and also has a high potential difference between bright areas and dark areas during continuous image formation by edge-reversing charging exposure. It is an electrophotographic photoreceptor with particularly excellent durability because of its small potential fluctuations.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer laminated on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) In the formula, R_1 and R_2 represent an alkyl group, an aryl group, or an aralkyl group that may have a substituent, and may be the same or different. R_3 is a hydrogen atom, an alkyl group that may have a substituent,
Aryl group, aralkyl group or -SR_7 group (R_7
represents an alkyl group, an aryl group or an aralkyl group. R_4, R_5 and R_6 represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group, a halogen atom or a -SR_7 group, and may be the same or different. However, when R_1 and R_2 have a substituent, at least one of R_3, R_4, R_5, and R_6 is a -SR_7 group, and when there are two or more -SR_7 groups, R_7 are not the same. It's fine. X is an ethylene group, a vinylene group, an oxygen atom, an amino group (=
N-R_8) or a sulfur atom, and R_8 represents an alkyl group, an aryl group, or an aralkyl group.