JPS6314156A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity to visible light, electric charge holding power, surface strength, etc., by providing a layer contg. a specific carbazole compd. to the titled body. CONSTITUTION:The carbazole compd. expressed by the formula is used for the electric charge transfer material of the electrophotographic sensitive body, the photosensitive layer of which is separated in function to an electric charge generating layer and an electric charge transfer layer. A soln. prepd. by dissolving the compd. and binder in a suitable solvent is coated on said body and dried. The binder is exemplified by a polyacrylate, polysulfone, etc., and the content of the carbazole compd. is incorporated in the binder preferably at 10-500pts.wt. per 100pts.wt. binder in the compounding ratio of the binder and the carbazole compd. The photosensitive body which has the high sensitivity and high durability and is applicable to a wide range of fields where electrophotographs are utilized.

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] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are conventionally 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 being able to rapidly dissipate charge when irradiated with light. , has the disadvantage of six poles.

For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure, and especially when the ambient temperature exceeds 40°C, crystallization becomes significant, resulting in decreased charging performance and spots on the image. There are drawbacks such as: Cadmium sulfide photoreceptors cannot provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. Since the sensitive dye deteriorates due to corona charging and fades due to exposure light, it has the disadvantage that it cannot provide stable images over a long period of time.

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

In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds disclosed 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 is not sufficiently sensitive.

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, US Pat. No. 383
It is disclosed in US Pat. No. 7,851, US Pat. No. 3,871,882, and the like.

However, the sensitivity and characteristics of conventional electrophotographic photoreceptors using low-molecular organic photoconductors in the charge transport layer are not necessarily sufficient, especially when repeated charging and exposure are performed. There are large fluctuations and 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 further to provide a charge generating layer and a charge generating layer. An object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer which is functionally separated from the charge transport layer.

[Means for Solving Problems, Effects] The present invention comprises an electrophotographic photoreceptor characterized by having a layer containing a carbazole compound represented by the following general formula.

In the general formula, R1 represents an alkyl group such as methyl, ethyl, propyl, butyl, etc., which may have a substituent, a 7-ralkyl group such as benzyl, phenethyl, or naphthylmethyl, or an aryl group such as phenyl or naphthyl, and R2 -R8 is a halogen atom such as a hydrogen atom, a fluorine atom, a chlorine atom, or a bromine atom; Indicates an alkoxy group or an amino group, and furthermore, R2 and R3, R3 and R4, R4
and R5 and R6 and R7 each represent a residue forming a benzene ring which may have a substituent, and A is an aromatic ring group such as phenyl or naphthyl, which may have a substituent, or pyridyl or indolyl. , represents a heteroaromatic group such as quinolyl, benzothenyl, and the above alkyl group,
Aralkyl group, aryl group, alkoxy group, amine group,
Substituents that the benzene ring-forming residue, aromatic ring group, and heteroaromatic ring group may have include alkyl groups such as methyl, ethyl, and propyl, alkoxy groups such as methoxy, ethoxy, and propoxy, fluorine atoms, chlorine atoms, and bromine. Examples include halogen atoms, cyano groups, nitro groups, substituted amine groups, etc., and the substituents of the substituted amine groups include alkyl groups such as methyl, ethyl, propyl, butyl, alkyl groups, alkoxy groups, halogen atoms, Examples include aromatic ring groups which may have additional substituents such as a nitro group and a cyano group.

Representative examples of the carbazole compound represented by the above general formula in the present invention are listed below.

Hi Thu OH.

OH3 Hj C, Hr C Yu H.

(6) CpHr C.H.E. -C4Hs 嘗 (l　6) zk (2l) L change C Yu H.

C Yu H5- blasphemy n-C now Hs n-C+H.

Regarding the synthesis of the carbazole compound represented by the above general formula, a method for synthesizing compound example (4) will be explained as a representative example.

In addition to 10.0 g (32.3 mmol) of 9-ethyl-3-diazonium rubazole tetrafluoroborate and 320 cc of onitrobenzene, an additional 6.34 g of potassium acetate was added.
g (64.6 mmol) and 1.2 cc of acetonitrile
After washing the reaction solution with water and drying with anhydrous sodium sulfate, nitrobenzene and the like are distilled off under reduced pressure.

The residue was purified with a silica gel column to obtain 9.41 g of 3-(p-nitrophenyl)-9-ethylcarbazole.

This was reduced and ethylated using a conventional method to obtain 9.11 g of the target compound.

The yield was 82.9%.

Elemental analysis value Calculated value (X) Measured value (X) C84
, 4284, 38 H7, 387, 41 N 8.20 8.21 Other exemplified carbazole compounds are also synthesized in a similar manner.

In a preferred embodiment of the present invention, the charge transport material of an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer is carbazole represented by the above general formula. A carbazole compound represented by the above general formula can be used as a charge transport material of an electrophotographic photoreceptor which is functionally separated into a layer and a charge transport layer.

The charge transport layer in the present invention is preferably formed by coating and drying a solution in which a carbazole compound represented by the above general formula and a binder are dissolved in a suitable solvent.

Examples of the binder include polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin,
Methacrylic resin, polyvinyl chloride, polyvinyl acetate, phenolic resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or a copolymer containing two or more repeating units of these resins, such as styrene-butadiene copolymer, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, and the like. In addition to such insulating resins, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene, and polyvinylpyrene can also be used.

The blending ratio of the binder and the carbazole compound is 10 to 5 parts of the carbazole compound per 100 parts of the binder.
It is preferable to set it as 00 parts by weight.

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, the charge transport layer may be laminated on or below the charge generation layer, but it is preferable that the charge transport layer is laminated on the charge generation layer. .

The charge transport layer has a limit in its ability to transport charge carriers, so it cannot be made thicker than necessary. Generally, the thickness is 5 to 30 tiles, but the preferred range is 8 to 20 tiles.

The solvent used to form the 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 underlying undercoat layer.

For example, alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexane, and N.

Amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, and tetrahydrofuran.

Ethers such as dioxane and ethylene glycol monomethyl ether, esters such as methyl acetate and quasi-ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene, or benzene and toluene. Aromatic hydrocarbons such as 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 Meyer bar coating method, a plate coating method, a roller coating method, or a curtain coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry.

Heat drying can be carried out at 30 to 200°C for 5 minutes to 2 hours, either stationary or with ventilation.

The charge transport layer 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, various fluorocarbons There are many types.

The charge generating layer in the present invention includes selenium, selenium-tellurium, pyrylium dye, thiapyrylium dye, asthrenium dye, phthalocyanine pigment, 77thanthrone pigment, dibenzpyrenequinone pigment, pyranthrone pigment, trisazo pigment, disazo pigment, monoazo pigment, and indigo pigment. ,
Quinacridone [4, thiacyanin, asymmetric chimesyanin, quinocyanin, etc. or JP-A-54-143645
Such as amorphous silicon described in the publication! It can be formed as a vapor deposited layer or a resin dispersion layer using a charge generating substance.

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

11λ raw I (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (1B) (2B) (4S)
Indigo dye (80) Thioindigo dye (81) β-copper-coated phthalocyanine (8B) The charge generation layer is formed by dispersing the above charge generation substance in a suitable binder and coating it on the substrate. It can also be obtained by forming a vapor deposited film using a vacuum evaporation apparatus.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, and
It can be selected from organic photoconductive polymers such as N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably, polyvinyl butyral, polyarylate (
Insulating materials such as polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, polyurethane, casein, polyvinyl alcohol, polyvinylpyrrolidone, etc. For example, polyester resins can be mentioned.

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

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 , esters such as ethyl acetate.

Fat layer halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene; aromatic hydrocarbons such as benzene, toluene, xylene, lig, loin, monochlorobenzene, dichlorobenzene, etc. Can be mentioned.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Meyer bar coating method, blade coating method,
This can be done by using a coating method such as a roller coating method or a curtain coating method.

The charge generation layer contains as much of the charge generation substance as possible in order to obtain sufficient absorbance and to shorten the range of the generated charge carriers.

Thin film layer, e.g. 5 IL or less, preferably 0.01 to I
A thin film layer having a film thickness of JL is desirable.

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 conductive substrate.

Examples of the substrate having a conductive layer include aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium molybdenum, chromium,
Examples include titanium, nickel, indium, gold, platinum, etc. Others include aluminum, aluminum alloy,
Plastics (e.g. polyethylene, polypropylene) having a layer formed by vacuum evaporation of indium oxide, tin oxide, indium oxide-tin oxide alloy, etc.

Polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), conductive particles (e.g. carbon black, silver particles, etc.) coated on plastic with a suitable binder, conductive particles coated with plastic or paper Examples include substrates impregnated with carbon dioxide and plastics containing conductive polymers.

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

The undercoat layer is casein and polyvinyl alcohol.

Nitrocellulose, ethylene-acrylic acid copolymer,
It can be formed from polyamide (Nylon 6, Nylon 66, +Yelon 610, co-ffi nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc.

The thickness of the undercoat layer is 0.1 to 5 JL, preferably 0.1 to 5 JL.
A range of 5 to 3 wins is appropriate.

When using a photoreceptor with 8tAL in the order of conductive layer, charge generation layer, and charge transport layer, the carbazole compound represented by the above general formula of the present invention has a hole transport property, so that the surface of the charge transport layer is negatively charged. When exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the negative charges.
Attenuation of the surface potential occurs, creating an electrostatic contrast with the unexposed area. It is necessary to use positively charged toner during development.

In another embodiment of the present invention, disazo pigments or pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzopyrylium dyes disclosed in U.S. Pat. lium dye, benzothiapyrylium dye,
Photoconductive pigments and dyes such as naphtopyrylium dyes can also be used as sensitizers.

In another embodiment, a eutectic complex of a pyrylium dye and an electrically insulating polymer having a fullkylidene diarylene moiety as disclosed in US Pat. No. 3,684,502 may be used as a sensitizer.

This eutectic complex is composed of 1 e.g. ) in a halogenated hydrocarbon solvent (e.g. dichloromethane, chloroform, carbon tetrachloride, 1.1-dichloroethane, 1.2-dichloroethane).

1.1.2-Trichloroethane, chlorobenzene, bromobenzene, l,2-dichlorobenzene) and then dissolved in a non-polar solvent (e.g. hexane, octane, decane, 2,2,4-trimethylbenzene, ligroin). is obtained as a particulate eutectic complex by adding .

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-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 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.

[Example] Example 1 β-type copper phthalocyanine (trade name: LionolBlue)
NCB Toner (manufactured by Toyo Ink Manufacturing Co., Ltd.) with water,
7 g of pigment purified by filtration after sequential reflux in ethanol and benzene, trade name: Polyester Adhesive 49
000 (solid content 20%, manufactured by DuPont), 35 g of luene, and 35 g of dioxane were mixed, and the mixture was milled in a ball mill.
A coating solution was prepared by dispersing the mixture over time. This coating liquid was applied onto an aluminum sheet using a Mayer bar to a dry film thickness of 0.51 L to form a charge generation layer.

Next, the carbazole compound example (4) is used as a charge transport material.
) compound 7g and polycarbonate (product name Panrai)
A solution obtained by stirring and dissolving 7 g of K-1300 (manufactured by Teijin Mari) in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene was placed on top of the charge generation layer using a Mayer bar until the dry film thickness was 11 l. An electrophotographic photoreceptor having a photoreceptor having a two-layer structure was prepared.

This electrophotographic photoreceptor was tested using an electrostatic copying paper tester Mode! manufactured by Kawaguchi Electric. L-5P-428 was charged with corona at 15 KV using the test static method, and after being held for 1 second in a dark place, the illumination intensity was 5! It was exposed to Lux and the charging characteristics were measured.

As for the charging characteristics, the surface potential (Vo) and the exposure amount (E1/2) required to attenuate the potential (vl) when dark decayed for 1 second to 1/2 were measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential when the electrophotographic photoreceptor prepared above is repeatedly used, it was pasted on the photosensitive drum cylinder of a PPC copier (trade name: NP-1502, manufactured by Canon ■). , so, ooo on the same plane
Copies were made, and changes in bright area potential (VL) and dark area potential (Vo) were measured at the initial stage and after 50,000 copies were made.

In addition, Comparative Material 1 was prepared in exactly the same manner as in Example 1 except for using the compound in place of the carbazole compound example (4), and was measured in the same manner.

The results are shown below.

V□ (-V)Vl (-V)El/2 (lux, 5
ea) Example 1 690 681 1.9 Comparison data 1 677 659 12.7 Initial period After 50,000 sheets durability Example I VD (-V) 690 681VL
(-V) 141 169 Comparative material I VD(-V) 676 580VL
(-V) 151 221 As is clear from the above results, the electrophotographic photoreceptor using the carbazole compound represented by the above general formula of the present invention in the charge transport layer has high sensitivity and high durability in Examples 2 to 1. In Example 1, in place of the charge transport substance used in Example 1, a carbazole compound example (2
), (5), (6), (7), (8), (10), (1
3), (16), (18), (20), (22), (2
Using the compounds of 3), (27), (28), and (32),
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the pigment of Example (44) was used as the charge-generating substance.

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

2 (2) 690 688 2.43
(5) 688 679 2.14 (6)
686 675 2.35 (7) 69
0 679 2.66 (8) 688 67
5 2.27 (10) 690 680 2.
38 (13) 687 677 2
．． 19 (16) 686 676
2.410 (18) 690 680
1.911 (20) 687
682 2.112 (22) 688
679 2.013 (23) 6
86 677 2.414 (27)
690 681 2.51s (28)
s90 878 2.016 (32)
687 679 2.9 early
After 50,000 sheets durability 2 690 181 6g3 2113 6.
87 138 678 16016 68.
6 153 673 173 Example 17 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 222 mjl of water) was coated on an aluminum cylinder by dip coating and dried to give a coating amount of 1.0 g/m2. A subbing layer was formed.

Next, 1 part by weight of the exemplified pigment (78) as a charge generating substance, butyral resin (trade name Kosurek 3M-2, ti1
1 part by weight (manufactured by Suikagaku ■) and 30 parts by weight of isopropyl alcohol were dispersed in a ball mill for 4 hours. This dispersion was coated on the previous subbing layer by a dip coating method and dried to form a charge generating layer, which had a thickness of 0.3 l.

Next, 1 part by weight of the charge transport material of the carbazole compound example (3), polysulfone (P-1700, ucc?lJ
) 1 part by weight of fk and 6 parts by weight of monochlorobenzene were mixed and stirred with a stirrer to dissolve. This liquid was applied onto the previous charge generation layer by a dip coating method and dried to form a charge transport layer. The film thickness was 127L.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared.

The surface potential (initial potential Vo) at this time was measured. 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 amount of exposure (El/2J/cm2) required to attenuate the potential V by 1/2 after dark decay.

At this time, a gallium/aluminum/arsenic ternary semiconductor laser (output 5 mW, oscillation wavelength 78 mW) was used as a light source.
0 nm) was used. Show the results.

Vony 685V Potential holding rate (VK/VOX100): 95%E 1
/ 2: 2, l JLJ / c
m2 Next, the photoreceptor of a laser beam printer (product name: LBP-LX, manufactured by Canon Corp.), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser as above, was replaced with the photoreceptor of the present invention and set. An image formation test was conducted under the conditions shown below.

Surface potential knee after primary charging: 700 V, surface potential knee after image exposure: 150 V (exposure amount: 1.2 J/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: 50IL
Full red exposure of ux, sec.

Image formation was performed by line scanning in accordance with laser beam character signals and image signals.

Good prints of both text and images were obtained.

Example 18 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium verchlorate and 5 g of the charge transport material of the carbazole compound example (14) were added to polyester (same as above) in toluene-dioxane. (50:50
) The solution was mixed with 100 mJl and dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum sheet using a Mayer Parr so that the film thickness after dry M4 was 153L.

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

v,, knee 688V, V1 knee 678VEl/2:2.
4 lux, sec Initial Vow - 687V, VL Knee 143V After 50,000 sheets durability Vo Knee 677V, ML Knee 171V Example 19 Casein ammonia aqueous solution (casein 1
1.2g, 28% ammonia water 1g, water 222 mal
) with a Mayer bar and dry, the film thickness is! The adhesive layer of the road was formed.

Next, 5 g of the disazo pigment of charge generating substance example (16) and 2 g of butyral resin (butyralization degree 63%) were dispersed with a solution dissolved in 95 mJl of ethanol, and then coated on the adhesive layer, and the film thickness after drying was A charge generation layer was formed in which the charge was 0.4p.

Next, 5 g of the charge transport material of the carbazole compound example (2) and poly-4,4'dioxydiphenyl-2,2-
5g of propane carbonate (viscosity average molecular weight 30,000) and 150m of dichloromethane! An electrophotographic photoreceptor was prepared by applying a solution dissolved in L to a charge generation layer and drying it to form a charge transport layer having a thickness of 1iIL.

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

vo knee 689V, Vl knee 680Vel/2:
2.01ux, sec Initial v,, VL knee 138V After 50,000 sheets durability Vo knee 678V, VL knee 159V Example 20 Glow discharge deposition of a 0°2 mm thick molybdenum plate (substrate) with a cleaned surface The inside of the zero-order tank, which was fixed at a predetermined position in the tank, was evacuated to a degree of vacuum of about 5XlO-6 torr. Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank, and the gas flow rate and main valve of the deposition tank were adjusted to stabilize the 0.5 torr. High frequency power is applied to generate glow discharge inside the coil in the tank.30
The input power was set to W. An amorphous silicon film was grown on the substrate under the above conditions, and after the same conditions were maintained until the a thickness became 2-way, the glow discharge was stopped. After that, turn off the heater and high frequency power supply, wait until the substrate temperature reaches 100℃, close the hydrogen gas and silane gas outflow valves,
Once the inside of the tank was lowered to 10-5 torr or less, 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 the same manner as in Example 1 except that the above carbazole compound example was used as a charge transport material. The photoconductor thus prepared was installed in a charging exposure experiment equipment, and the photoreceptor was exposed to -6KV.
It was charged with corona 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, a positively charged developer (including toner and carrier) was cascaded onto the photoreceptor surface to obtain a good toner image on the photoreceptor surface.

Example 21 3 g of 4-(4-dimethylaminophenyl)-2,8-diphenylthiapyrylium verchlorate and poly(4,4
”-isopropylidene diphenylene carbonate) 3g
was sufficiently dissolved in 200 ml of dichloromethane, and 1 ml of toluene was added to precipitate the eutectic complex. After filtering this precipitate, dichloromethane was added to dissolve it again.
Next, 100 mjL 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 ml of a methanol solution containing 2 g of polyvinyl butyral and dispersed in a ball mill for 6 hours. After drying, this dispersion was applied onto an aluminum plate having a casein layer using an ear bar to a film thickness of 0.41 L to form a charge generation layer.

Next, the above carbazole compound example (
A charge transport layer was formed on the charge generation layer in the same manner as in Example 1 except that the substance of 21) was used. The electrophotographic properties of the thus prepared photoreceptor were measured in the same manner as in Example 1. The results are shown below.

V6 knee 690V, Vl knee 684VEl/2:
2.91ux, sec Initial VD Knee 687V, ML Knee 147W After 50,000 sheets durability VD Knee 680V, vL Knee 170V Example 22 5 g of a eutectic complex similar to the eutectic complex used in Example 21 and the carbazole compound example ( 4) 5 g of the charge transport material was added to 150 mj of polyester (described above) in tetrahydrofuran solution.
L and thoroughly mixed and stirred. The film thickness after drying this liquid with a Mayer bar on an aluminum sheet was 151L.
It was applied so that The electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1. Show the results.

V6 knee 688V, Vt knee 679VEl/2:
2.0jLux, sec Initial VD Knee 687V, VL Knee 139V After 50,000 sheets endurance VO: -680V, VL Knee 157V[
Effects of the Invention] The electrophotographic photoreceptor of the present invention uses a specific carbazole compound as a charge transporting substance, so it has high sensitivity and durability (significantly less potential fluctuation due to use of reversal), and is suitable for use in the field of electrophotography. It has the remarkable effect of being applicable to a wide range of areas.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor characterized by having a layer containing a carbazole compound represented by the following general formula. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ In the formula, R_1 represents an alkyl group, aralkyl group, or aryl group that may have a substituent, and R_2 to R_8 are a hydrogen atom, a halogen atom, or a substituent. represents an alkyl group, alkoxy group or amino group which may be R
_2 and R_3, R_3 and R_4, R_4 and R_5, and R_6 and R_7 represent residues forming a benzene ring which may have a substituent, and A is an aromatic ring group or a heteroaromatic group which may have a substituent. Indicates a ring group.