JPS62289846A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance repeated use characteristics of a photosensitive body by using a specified indoline derivative as an electric charge transfer material. CONSTITUTION:The photosensitive layer is functionally separated into an electric charge generating layer, and a charge transfer layer containing as the charge transfer material one of the indoline derivatives represented by the formula shown on the right in which R1 is alkyl, aralkyl, or aryl; each of R2-R4 is H, halogen, alkyl, or the like; R5 is H, alkyl, aralkyl, or the like; R6 is alkyl, aralkyl, a heterocyclic group, or the like, and it is preferred that each of R5 and R6 is optionally substituted phenyl, thus permitting the obtained electrophotographic sensitive body to be enhanced in sensitivity characteristics and reduced in variation of the difference between potentials in the light and in the dark after repeated cycles of electrification and exposure.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, to a low-molecular organic photoreceptor that provides improved electrophotographic properties. The present invention relates to an electrophotographic photoreceptor having the following.

[Conventional technology]

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or quickly dissipating the charge when irradiated with light. On the other hand, it has various drawbacks. For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure.
In particular, when the ambient temperature exceeds 40° C., crystallization becomes significant, resulting in drawbacks such as a decrease in chargeability and the appearance of white spots on images. Cadmium sulfide photoreceptors do not provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. They have the disadvantage that they cannot provide stable images over a long period of time because the sensitive dyes undergo charging deterioration due to corona charging and photobleaching due to exposure light.

On the other hand, various advanced conductive polymers such as polyvinylcarbazole have been proposed, but these polymers are superior in terms of film formability and light weight compared to the aforementioned inorganic photoconductive materials. However, it has been difficult to put them into practical use to date because sufficient film formation properties have not yet been achieved, and inorganic photoconductive materials lack sensitivity, durability, and stability against environmental changes. This was because it was inferior to the

In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat.
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 had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

On the other hand, 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, etc. Such an electrophotographic photoreceptor is disclosed in, for example, US Pat. No. 3,837,855.
No. 1, Publication No. 3871882, etc.

However, even with this laminated structure, electrophotographic photoreceptors using conventional low-molecular-weight organic photoconductors in the charge transport layer do not always have sufficient sensitivity and characteristics, and also require repeated charging and exposure. In some cases, there is a point where fluctuations in bright and dark potentials need to be greatly improved.

[Problem that the invention seeks to solve]

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

Another object of the invention is to provide a new organic photoconductor.

Another object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer in which a charge generation layer and a charge transport layer are functionally separated.

[Means for solving problems]

That is, the present invention provides general formula (I): R7 (wherein R3 is an alkyl group which may have a substituent,
Indicates an aralkyl group or an aryl group, Rz, R:l
, R4 represents a hydrogen atom, a halogen atom, or an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and R2 represents a hydrogen atom or an alkyl group, an aralkyl group, or an aryl group that may have a substituent. Show, R
3 is an alkyl group that may have a direct substituent, an aralkyl group,
Represents a ring group or a heterocyclic group. ) This is an electrophotographic photoreceptor characterized by having a photosensitive layer containing an indoline compound represented by the following formula.

The present invention will be explained in detail below.

More specifically, the indoline compound represented by the general formula (I) used in the present invention is as follows.

That is, in the general formula (1), R is a methyl group,
Alkyl groups such as ethyl group, linear or branched propyl group, butyl group, pentyl group; aralkyl group such as hensyl group, phenethyl group; phenyl group, naphthyl group,
It is an aryl group such as anthryl group. These alkyl groups, aralkyl groups and aryl groups may have a substituent, and examples of substituents include alkyl groups such as methyl and ethyl groups; halogen atoms such as chlorine and bromine; methoxy and ethoxy groups; Alkoxy groups; aryloxy groups such as phenoxy groups; substituted amino groups such as dimethylamino groups and diethylamino groups.

R2, R3 and R4 are hydrogen atoms; chlorine atoms.

Halogen atoms such as bromine atoms; methyl groups, ethyl groups; alkyl groups such as linear or branched propyl groups, butyl groups, pentyl groups; aralkyl groups such as benzyl groups and phenethyl groups; phenyl groups, naphthyl groups, anthryl groups It is an aryl group such as a group.

These alkyl groups, aralkyl groups, and aryl groups may have substituents, such as alkyl groups such as methyl and ethyl; halogen atoms such as chlorine and bromine; methoxy and ethoxy groups; alkoxy group;
Examples include aryloxy groups such as phenoxy group; substituted amino groups such as dimethylamino group and diethylamino group.

R6 is a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, or a pentyl group; an aralkyl group such as a benzyl group or a phenethyl group; a phenyl group, a naphthyl group, an anthryl group R6 is an aryl group such as a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, etc.; an aralkyl group such as a benzyl group, a phenethyl group; a phenyl group, Aryl groups such as naphthyl group and anthryl group; pyridine, quinoline, hendioxazole,
These are monovalent heterocyclic groups such as benzothiazole, benzimidazole, benzotriazole, phenylbenzoxazole, phenylbenzothiazole, phenylbenzimidazole, dibenzofuran, carbazole, xanthine, phenothiazine, and diphenyloxadiazole.

These alkyl groups, aralkyl groups, aryl groups, and heterocyclic groups may have a substituent, and the substituents include alkyl groups such as methyl and ethyl groups; halogen atoms such as chlorine and bromine; Alkoxy groups such as methoxy and ethoxy groups; Aryloxy groups such as phenoxy groups;
Examples include substituted amine groups such as dimethylamino and diethylamino groups.

As will be clear from the description below, the indoline compound of the present invention can be combined with various charge generating substances to provide an electrophotographic photoreceptor with excellent repeatability. Especially the general formula <
In 1), when R3 and R2 are the same phenyl group which may have a substituent, the repeatability is even better. This is thought to result in less photodeterioration due to the symmetry in which anti- and syn-type optical isomers do not occur, thereby preventing an increase in residual potential and dramatically improving durability.

Next, a method for synthesizing the indoline compound represented by the general formula (I) will be described.

General formula (II) below [In the formula, Rs and R- are the same as in general formula (1).

Show Roan. ) or a dialkyl group represented by -PO(OR)z (wherein R represents a lower alkyl group)] and the compound represented by the following general formula (II[)R.

[In the formula, R+, Rz, R3, and Ra are the same as in general formula (1)] It can be obtained by reacting an aldehyde compound represented by the following in the presence of a basic catalyst.

Basic catalysts include sodium hydroxide, potassium hydroxide, sodium amide hydride and alcoholades such as sodium methylate and potassium t-butoxide.

Reaction solvents include methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1.2
-dimethoxyethane, bis(2-methoxyethyl) ether, dioxane, tetrahydrofuran, toluene, xylene, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc. can be mentioned.

Among them, polar solvents such as N,N-dimethylformamide,
Dimethyl sulfoxide is preferred.

Representative examples of the compound represented by general formula (1) are listed below.

Compound example Hff (2)I H3 C,H.

(4)I C, +1.

C41 (Q (8)I CHl α[+1 1 CI+.

In a preferred specific example of the electrophotographic photoreceptor according to the present invention,
The compound represented by the above general formula (1) can be used as a charge transport 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 according to the present invention is preferably formed by applying a solution prepared by dissolving the compound represented by the general formula (1) and a binder in a suitable solvent and drying the solution. 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 containing two or more repeating units of these resins, such as styrene-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 exemplified compound of the present invention is preferably 10 to 500 parts by weight per 100 parts by weight of the binder.

The charge transport layer is electrically connected to the underlying charge generation layer, and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. have. 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 between 5 microns and 30 microns. However, the preferred range is 8 microns to 20 microns.

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 isopropanol, ketones such as acetone, notyl 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 henzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating can be performed using coating methods such as dip coating, spray coating, spinner coating, bead coating, Meyer bar coating, blade coating, roller coating, and curtain coating. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30℃ to 200℃ for 5 minutes or more
It can be carried out stationary or under blown air for a time in the range of 2 hours.

The charge transport layer of the present invention can contain various additives. Such additives include diphenyl, diphenyl chloride, 0-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilaurylthiopropionate. , 3,5-dinitrosalicylic acid, and various fluorocarbons.

The charge generation layer used in the present invention includes selenium, selenium-tellurium, pyrylium, thiopyrylium, azulenium dyes,
Phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, trisazo pigments, disazo pigments, azo pigments, indigo pigments, quinacridone pigments, thiacyanine, asymmetric quinocyanine, quinocyanine or as described in JP-A-54-143645 A separate monolayer or resin dispersion layer selected from a charge generating material such as amorphous silicon can be used.

Examples of the charge generating substance used in the electrophotographic photoreceptor of the present invention include the following inorganic compounds and organic compounds.

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ν The charge-generating layer can be formed by dispersing the charge-generating substance described above in a suitable binder and coating it on the substrate, or it can be obtained by forming a vapor-deposited film using a vacuum evaporator. Can be done. Binders that can be used to form the charge generating layer by coating 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, polyvinylpyridine, cellulose resin, urethane resin , epoxy resin, casein, polyvinyl alcohol, polyvinylpyrrolidone, and other insulating resins. The amount of resin contained in the charge generation layer is preferably 80% by weight or less, preferably 40% by weight or less. Organic solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone, 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, methyl acetate, acetic acid Esters such as ethyl, aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, halogenated hydrocarbons, or aromatics such as benzene, toluene, xylene, ligroin, 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.

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and is preferably a thin film layer, for example less than 5 microns, in order to shorten the range of the generated charge carriers. is preferably a thin film layer having a thickness of 0.01 micron to 1 micron. 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, but are transferred to the charge transport layer. This is due to the need for injection.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and in addition, plastics having a layer formed by vacuum evaporation of aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. (for example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) with a suitable binder. Plastic or a substrate coated on the conductive substrate, a substrate made of plastic or paper impregnated 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 layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 6101 copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the undercoat layer is suitably 0.1 micron to 5 micron, preferably 0.5 micron to 3 micron.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, the compound has hole transport properties, so the surface of the charge transport layer must be negatively charged, and if exposed after being charged, it will be exposed to light. In the part, holes generated in the charge generation layer are injected into the charge transport layer,
After that, it reaches the surface and neutralizes the negative charge, causing a decrease in surface potential and creating an electrostatic contrast with the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

In another specific example of the present invention, the above-mentioned disazo pigment or pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzopyrylium dyes disclosed in U.S. Pat. No. 3,554,745, U.S. Pat. , benzothiapyryllium dye, naphthopyryllium dye, naphthothiapyrylium dye, and other photoconductive 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, as disclosed in US Pat. No. 3,684,502, can also 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 (e.g., dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, , 2-dichloroethane, 1,1.2-trichloroethane, chlorobenzene, bromobenzene, 1.
2-dichlorobenzene) and then dissolved in a non-polar solvent (e.g. hexane, octane, decane, 2.2.4
- Obtained as a particulate eutectic complex by adding trimethylbenzene and ligroin.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-butadiene copolymer,
Acrylonitrile copolymers, vinyl acetate-vinyl chloride copolymers, polyvinyl butyral, polymethyl methacrylate, poly-N-butyl methacrylate, polyesters, cellulose esters, and the like can be contained as binders.

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 a highly sensitive electrophotographic photoreceptor, and the present invention has the advantage that fluctuations in bright area potential and dark area potential are small when charging and exposure are repeatedly performed.

〔Example〕

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

Example 1 β-type copper fuclocyanin (part name Li manufactured by Toyo Ink manufacturer)
onol Blue NCB Toner) in water, ethanol and benzene, and then filtered and purified; 14 g of "Product name: Polyester Adhesive 49,000 (solid content 20%)" manufactured by DuPont;
A coating solution was prepared by mixing 35 g of toluene and 35 g of dioxane and dispersing the mixture in a ball mill for 6 hours. This coating liquid was applied onto an aluminum sheet using a Mayer bar to a dry film thickness of 0.5 microns to form a charge generation layer.

Next, as a charge transport compound, the exemplified compound 11 was added to 7
A solution obtained by stirring and dissolving 7 g of polycarbonate resin (trade name "Panlite K-1300j" manufactured by Kijin Kasei ■) in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene was placed on the charge generation layer. Electrophotographic application field 1 with a two-layer photosensitive layer coated with a Mayer bar to a dry film thickness of 11 microns
It was created.

The electrophotographic photoreceptor thus prepared was statically charged with a corona at 15 kV using an electrostatic copying paper tester (Model-SP-428, manufactured by Kawaguchi Denki), and then placed in a dark place for 1
After being held for a second, it was exposed to light at an illuminance of 2.5 lux, and the charging characteristics were examined.

As for charging characteristics, the surface potential (■.) and the exposure amount (E 1/2) required to attenuate the potential (■1) 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 photoreceptor prepared in this example was used in a Canon ■ PPC copying machine (Canon ■ NP-1502).
By pasting it on the photosensitive drum cylinder of
After initial setting by adjusting the primary charging and exposure amount to 0 V, 50,000 copies were made, and fluctuations in bright area potential (VL) and dark area potential (Vn) were measured at the initial stage and after 50,000 copies were made.

Comparative sample 1 was prepared in exactly the same manner using a stilbene compound having the following structural formula in place of the exemplified compound, and measured in the same manner.

The results are shown below.

Table 1 Examples 2 to 21 Electrophotographic application fields 2 to 21 were prepared in exactly the same manner as in Example 1 except that the charge generation substance and the charge transport substance of the present invention were replaced with those shown in Table 2. , Example 1
The charging characteristics were measured in the same manner as above. The results are shown in Table-2.

Example 22 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 22.2 mj of water) was coated on an aluminum cylinder by dip coating, dried and coated with a coating of 11.0 g/m. formed a layer.

Next, 1 part by weight of the charge-generating substance of Example 11h79, 1 part by weight of butyral resin (S-LEC B2, manufactured by Sekisui Kagaku Jin) and 30 parts by weight of isopropyl alcohol were dispersed for 4 hours using a ball mill disperser. This dispersion was applied onto the previously formed subbing layer by a dip coating method and dried to form a charge generating layer. The film thickness at this time was 0.3 microns.

Next, 1 part by weight of a charge transfer substance per milliliter of the exemplary compound;
1 part by weight of polysulfone resin (P1700, manufactured by Union Carbide) and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer. This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time was 12 microns.

A corona discharge of 15 kV was applied to the photoreceptor thus prepared. The surface potential at this time was measured (initial potential ■). Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (attenuation). Sensitivity was evaluated by measuring the exposure amount (E17□ microjoule/cflI) required to attenuate the potential ①3 after dark decay to 1/2.

At this time, the light source was a gallium/aluminum/propylene ternary semiconductor laser (5n+W, oscillation wavelength 780 nm).
na+) was used. These results were as follows.

■. Knee 610 volt potential retention rate: 98% E+zz: 0.7 microjoules/cI11
Next is a laser beam printer (a reversal development type electrophotographic printer equipped with the same semiconductor laser as above).
The above photoconductor was attached to LBP-Cχ (manufactured by Canon LBP-CX).
An actual image forming test was conducted by replacing the photoreceptor with the following photoreceptor. The conditions are as follows.

Surface potential after primary charging: -700V, surface potential after image exposure: -150V (exposure amount μJ/cd), transfer potential: +7
00V, developer polarity; negative polarity, process speed; 50
1m/5eC1 development conditions (development bias) i-450V
, image exposure scanning method; image scan, - exposure before next charging; 5 Qlux-sec red full exposure image formation was performed by line scanning a laser beam according to character signals and image signals, but both characters and images were printed well. was gotten.

Example 23 3 g of 4-(4-dimethylaminophenyl)-2,6-diphenylthiapyrylium verchlorate and 5 g of the above-mentioned exemplary compound (m15) were added to polyester (Polyester Adhesive 49000: manufactured by DuPont) in toluene. (5
0)-dioxane (50) solution 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 microns.

Example 1 The electrophotographic characteristics of the photoreceptor produced in this way
It was measured in the same manner as. The results are shown below.

Vo: 580 port v, knee 515 volt E+ /z: 2.2 1ux 0
sec Kai - Comparison, Knee 700 volts VL Knee 150 volts, V, Knee 130 volts VL: -190 volts Example 24 An ammonia aqueous solution of casein (casein 1) was placed on an aluminum plate.
1.2g, 28% ammonia water 1g, water 222m! was coated with a Mayer bar and dried to form an adhesive layer with a thickness of 1 micron.

Next, 5 g of a disazo pigment having the following structure and 2 g of butyral resin (degree of butyralization: 63 mol%) were mixed with 9 mol of ethanol.
After being dispersed with a solution dissolved in 5I11, the charge generating layer was coated on the adhesive layer to form a charge generating layer having a dry film thickness of 0.4 microns.

Next, 5 g of the above exemplary compound (NlllO) and poly-4
, 4'-Dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight: 130,000) dissolved in 150 ml of dichloromethane was applied onto the charge generation layer and dried to form a charge transport layer with a thickness of 11 microns. An electrophotographic photoreceptor was prepared by forming the following.

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

■. Knee 620 volts V+ Knee 131o volts El/l: 1.2 1ux-secMJj circumference Vo Knee 7oo volts VL; -150 volts (knee 720 volts VL) Knee 175 volts Example 25 Surface clean A molybdenum plate (substrate) with a thickness of 2 mm was fixed at a predetermined position in a glow discharge deposition tank. Next, the inside of the tank was evacuated to a degree of vacuum of about 5 X I Q -'' torr. Thereafter, the input voltage of the heater was increased to stabilize the temperature of the molybdenum substrate at 150°C.

Thereafter, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank by eight people, and the gas flow rate and the main valve of the deposition tank were adjusted to stabilize the pressure at 0.5 torr. Next, 5MIIzO high frequency power was applied to the induction coil to generate glow discharge inside the coil in the tank, resulting in 30W of human power. An amorphous silicon film was grown on the substrate under the above conditions, and the same conditions were maintained until the film thickness reached 2 μm, after which glow discharge was discontinued. After that, turn off the heater and high frequency power supply, wait for the substrate temperature to reach 100℃, close the hydrogen gas and silane gas outflow valves, and temporarily heat the inside of the tank for 10-'tor.
After reducing the pressure to below r, the pressure was returned to atmospheric pressure and the substrate was taken out. Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1 except that exemplified compound 1tlo was used as the charge transport compound.

The photoreceptor thus obtained was installed in a charging exposure experimental device.
It was corona charged at 6 kV and immediately irradiated with a light image. The light image was illuminated through a transmission type test chart using a tungsten lamp light source. Immediately thereafter, an e-chargeable developer (containing toner and carrier) was cascaded onto the photoreceptor surface to obtain a good toner image on the photoreceptor surface.

Example 26 3 g of 4-(4-dimethylaminophenyl)-2,6-diphenylthiapyrylium verchlorate and poly(4,
4'-isopropylidene diphenylene carbonate) 3
g to 200mj of dichloromethane! After sufficiently dissolving the
100 mJ of toluene was added to precipitate the eutectic complex. After filtering this precipitate, dichloromethane was added to redissolve it, and then 100 mj 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 to form a charge generation layer so that the film thickness after drying was 0.4 microns.

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 1'h12 was used.

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

vo knee 590 volts V, knee 150 volts E+/z: 1.6 1ux "sec prayer-... VD: 700 volts VL knee 150 volts" y 曵県υ1入入■. Knee 730 volts VL Knee 185 volts Example 27 5 g of the same eutectic complex used in Example 26 and 5 g of the above-mentioned exemplified compound (Nall) were added to 150 mj of polyester (Polyester Adhesive 49000: manufactured by DuPont) in tetrahydrofuran solution! In addition, the mixture was thoroughly mixed and stirred. This liquid was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 μm.

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

■. Knee 6 to volt v, knee 600 volt El/l: 1.8 1ux-sec initial vD Knee 700 volt VL: 150 Bordeaux four extensions V, knee 730 volt VL: 180 volt [Effect of the invention] From the above As is clear, according to the present invention, by containing a specific low-molecular organic compound in the photosensitive layer, 1. It is possible to provide an unprecedented electrophotographic photoreceptor that has excellent sensitivity characteristics and improved fluctuations in bright area potential and dark area potential after repeated charging and exposure.

Claims (3)

[Claims] (1) General formula (I): ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 represents an alkyl group, aralkyl group, or aryl group that may have a substituent, R_2, R_3 ,
R_4 represents a hydrogen atom, a halogen atom, or an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and R_5 represents a hydrogen atom or an alkyl group, an aralkyl group, or an aryl group that may have a substituent. ,R
_5 represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group which may have a substituent. ) An electrophotographic photoreceptor comprising a photosensitive layer containing an indoline compound represented by the following. (2) The electrophotographic photoreceptor according to claim 1, wherein R_5 and R_6 in general formula (I) are the same phenyl group which may have a substituent. (3) The photosensitive layer is a functionally separated type consisting of a charge generation layer and a charge transport layer, and the charge transport layer has the general formula (I).
An electrophotographic photoreceptor according to claims 1 and 2, which contains a compound represented by: