JPH02178668A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity, electrophotographic characteristics, and variance between potentials in the light and in the dark and to enhance durability by incorporating a specified triarylamine compound in a photosensitive layer formed on a conductive substrate in an electrophotographic sensitive body. CONSTITUTION:The electrophotographic sensitive body is formed by laminating on the conductive substrate the photosensitive layer containing one of the triarylamine compounds represented by formula I in which each of Ar1 and Ar2 is a phenyl group and at least one of both is substituted, preferably, by an electron donative group, such as alkyl, embodied by methyl, which is higher than H in an electron donative property, and each of R1 and R2 is H, alkyl, or alkoxy. It is preferred to control the oxidation-reduction potential of the compound in the range of 0.6 - 0.88V, thus permitting the obtained electrophotographic sensitive body to be high in sensitivity and small in variance between potentials in the light and in the dark at the time of successive image formation by repeating cycles of electric charging and exposure, and superior in durability.

Description

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

There are manufacturing problems. Furthermore, inorganic photosensitive materials are generally highly toxic, and from this point of view, it is desired to use organic materials instead of inorganic materials for photoreceptors. In general, organic compounds are lighter than inorganic compounds, have superior film formability and flexibility, and are also cheaper to manufacture.Inorganic photoconductive materials such as cadmium sulfide have been widely used, but in recent years organic photoconductive materials have Research on the use of materials as electrophotographic photoreceptors has been actively conducted. Here, the basic characteristics required of an electrophotographic photoreceptor are: 1) It should be charged to an appropriate potential by corona discharge etc. in a dark place, 2) It should have good charge retention in a dark place, and 3) It should be exposed to light 4) The residual potential after irradiation with light is small.

Conventional electrophotographic photoreceptors using inorganic electrostatic materials such as selenium, zinc oxide, and cadmium sulfide have some basic properties, but have difficulty in film formation, poor flexibility, and manufacturing difficulties. Although the cost is high, it has not been put into practical use.

Until now, various organic photosensitive polymers including poly-N-vinylcarbazole have been proposed as typical organic electrophotographic photoreceptors.
These polymers are lighter than inorganic photoconductive materials,
Although they are excellent in terms of film-forming properties, they are inferior to inorganic photoconductive materials in terms of sensitivity, durability, stability against environmental changes, mechanical strength, etc., making it difficult to put them into practical use. In addition, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat. No. 3,837,851, etc.,
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in JP-A No. 828 and JP-A-51-94829 have been proposed. These low-molecular-weight organic photoconductors have been able to overcome the film-forming problems that had been a problem in the field of organic photoconductive polymers by appropriately selecting the binder used. It cannot be said that the sensitivity is sufficient.

For these reasons, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed in recent years. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like.

Many organic compounds have been proposed as charge transport materials. For example, pyrazoline compounds disclosed in JP-A No. 52-72231, hydrazone compounds disclosed in U.S. Pat. No. 842,431 and JP-A-55-52063,
Triphenylamine compounds of JP-A No. 7-195254 and JP-A-54-58445, JP-A-54-151
Stilbene compounds and the like are disclosed in Japanese Patent Application Laid-Open No. 955 and Japanese Patent Application Laid-Open No. 58-198043.

However, with conventional electrophotographic photoreceptors that use low-molecular-weight organic compounds as charge transport materials, the sensitivity and characteristics are not always sufficient (and when repeatedly charged and exposed, bright area potential and dark area potential change). Potential fluctuations are large and there are still points to be improved.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the various drawbacks of the conventional photoreceptors mentioned above.

Another object of the present invention is to provide a novel organic photoconductor that is easy to manufacture, relatively inexpensive, and has excellent durability.

[Means to solve the problem]

As a result of extensive research, the present inventors have discovered that a triarylamine compound represented by the following general formula (I) solves the above-mentioned problems and exhibits excellent effects.

That is, the present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, which is characterized by containing a triarylamine compound represented by the following general formula (I).

- In the formula, Ar1 and Ar2 represent a benzene ring, and at least one of them has an electron-donating substituent.

The electron-donating substituent refers to a substituent that is more electron-donating than hydrogen, specifically methyl.

Examples include alkyl groups such as ethyl and propyl, alkoxy groups such as methoxy and ethoxy, and substituted amino groups such as dimethylamino and diethylamino.

Ro and R2 are hydrogen atoms, methyl, and ethyl.

Indicates an alkyl group such as propyl or an alkoxy group such as methoxy or ethoxy.

Although it has been known in the past to use triarylamine compounds as charge transport materials, conventional triarylamine compounds generally have low sensitivity.

This is considered to be due to insufficient carrier injection from the charge generation layer to the charge transport layer.

In the present invention, in the above formula (1), Ar1 and Ar2
By introducing an electron-donating substituent into at least one of the benzene rings of the present invention, it is possible to achieve high sensitivity and excellent durability, as well as easy synthesis and inexpensive production, thus solving the problems of the past. In particular, compounds in which an electron-donating substituent is introduced into the benzene ring of Arl and/or Ar2 in the above-mentioned formula [I] and whose oxidation potential is 0.9 [V] or less have extremely good electrophotographic properties. shows. Among these, in particular, the oxidation potential is 0.60 [V] or more, 0.88 [V] or more.
V] The following compounds make it possible to realize an electrophotographic photoreceptor with extremely high sensitivity.

The reason for these is thought to be that in compounds with an oxidation potential exceeding 0.9 [V], the ability to inject carriers from the charge generation layer is insufficient;
Compounds with less than [V] have drawbacks such as increased dark capacitance and residual potential, resulting in poor electrophotographic properties, although the reason is not clear at present.

Therefore, in the triarylamine compound of formula (1) above, at least one of the benzene rings of Arl and Ar2 has an electron-donating substituent, and the oxidation potential is 0.6 [V ]~0.8
An electrophotographic photoreceptor using a compound in the range of 8 [V] is particularly preferred in terms of electrophotographic properties.

Representative examples of the compound represented by the general formula (1) are listed below, but the compound examples are not limited to these.

Examples of compounds (Margin below) death Eox indicates oxidation potential, and the unit is [V].

Furthermore, the method for measuring the oxidation potential will be described on the next page.

Method for measuring oxidation potential Use saturated calomel electrode as reference electrode IN(n-Bu)4NΦC
Using a lO4 acetonitrile solution, the potential of the working electrode was swept with a potential sweeper, and the peak position of the obtained current-potential curve was directly determined as the value of the oxidation potential.

For details, please refer to sample 0. IN (n-Bu)N”Cf
5-10 mmo1% in electrolyte of O4 acetonitrile solution
Dissolve to a certain concentration. Then, a voltage is applied to this sample solution, and the current change when the voltage is changed linearly from a low potential is measured to obtain a current-potential curve. The potential value at which the current value reached the peak in this current-potential curve was defined as the oxidation potential in the present invention.

Next, a synthesis example of the above compound will be shown.

(Synthesis method of compound example No. 10) 200mj with a thermometer and condenser! Ditolylamine 5.0g (0,025mol) in a Mitsuro flask
, iodobiphenyl 14.2g (0,051mol)
, anhydrous potassium carbonate 13.8g (0,100mol)
, 3.0 g (0,047 mo+) of copper powder, and 50 ml of orthodichlorobenzene were added, and the mixture was heated and stirred at reflux temperature for 20 hours. After cooling, remove solids by filtration.
The filtrate was concentrated under reduced pressure and ethanol was added to obtain yellowish-brown crystals of crude ditolylbiphenylamine. This crude product was applied to a silica gel column and developed with a toluene-hexane solvent, yielding 6.8 g of white crystals of purified ditolylbiphenylamine, yield 77.9%, mp,
Obtained at 726.5°C to I'17.7°C. Incidentally, an infrared absorption spectrum of this compound measured by the KBr tablet method is shown in FIG.

Elemental analysis C, H, N CHN Theoretical value 89.36% 6.63% 4.01% Actual value 89.40% 6.61% 3.99% Also, infrared rays of compound No. 13 synthesized in the same manner An absorption spectrum diagram is shown in FIG.

As described above, since the compound of the present invention can be easily synthesized in one step and in high yield, it is possible to supply an inexpensive electrophotographic material.

Note that compounds other than those on the synthesis side can also be synthesized using a similar method.

In a preferred embodiment of the present invention, a triarylamine compound represented by the above formula is used as a charge transport substance contained in the charge transport layer of an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. be able to.

The charge transport layer is preferably formed by applying a solution prepared by dissolving the compound represented by the above general formula and a binder in an appropriate 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 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 charge transport material of the present invention is preferably 10 to 500 parts by weight of the charge transport material per 100 parts by weight of the binder.

The charge transport layer is electrically connected to the charge generation layer below and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. In this case, this charge transport layer may be laminated on (or under) the charge generation layer. However, the charge transport layer may be laminated on the charge generation layer. It is desirable to be present.

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

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

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

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

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

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

The charge transport layer of the present invention may contain various additives. For example, plasticizers such as diphenyl, m-9-phenyl, dibutyl phthalate, silicone oil, grafted silicone polymers, surface lubricants such as various fluorocarbons, dicyanovinyl compounds, potential stabilizers such as carbazole derivatives, β-carotene, Examples include antioxidants such as Ni complexes and 1,4-diazabicyclo[2,2,2]octane.

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

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

As a general formula of an azo pigment, if we express the central skeleton as A1 A (:N=N-Cp) and the coupler part as Cp as shown below (where n=2°
r3), first, specific examples of A include the following.

R' A-14 A-15 p-a Specific examples of Cp include p-3 (R: alkyl, aryl, etc.). The central skeleton A and the coupler Cp form a pigment serving as a charge-generating substance by appropriate combination.

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

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less. Organic solvents used during coating include alcohols such as methanol, ethanol, and impropatol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N, N-dimethylformamide, N, N-dimethylacetamide, etc. , 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 benzene, toluene, xylene, monochlorobenzene,
Aromatics such as dichlorobenzene can be used.

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

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

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

As the conductive support, the support itself is conductive, such as aluminum, aluminum alloy, copper, zinc,
Stainless steel, 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., conductive particles (for example, aluminum powder) can be used. , titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) together with a suitable binder on a plastic or metal support, a support in which plastic or paper is impregnated with conductive particles, or a conductive support. For example, a plastic having a polymer with a chemical nature can be used.

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

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

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

In another specific example of the present invention, the above-mentioned disazo pigment, or the biryllium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzobyrylium dyes disclosed in U.S. Pat. No. 3,554,745, U.S. Pat. , benzothiapyryllium dyes, naphthopyryllium dyes, naphthothiapyrylium dyes, and other photoconductive pigments and dyes can also be used as sensitizers.

In another specific example, a eutectic complex of a biryllium dye and an electrically insulating polymer having an alkylidene diarylene moiety as disclosed in US Pat. No. 3,684,502 and the like can be used as a sensitizer. This eutectic complex is, for example, 4
-[4-bis-(2-chloroethyl)aminophenyl]
-2,6-Cyphenylthiapyrylium perchlorate and poly(4,4'-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent (e.g. dichloromethane, chloroform, carbon tetrachloride, l,1-dichloroethane, l,1-dichloroethane, .2-dichloroethane, 1,1.2-
) dichloroethane, chlorobenzene, bromobenzene,
1,2-dichlorobenzene) and then dissolved in a non-polar solvent (e.g. hexane, octane, decane, 2,2-dichlorobenzene).
．． A particulate eutectic complex is obtained by adding 4-trimethylbenzene and ligroin. 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.

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

Example 1 5 g of a disazo pigment represented by the following structural formula was mixed with 2 g of butyral resin (degree of butyralization: 63 mol%) and 100 m of cyclohexanone.
A coating solution was prepared by dispersing the mixture in a sand mill for 24 hours together with a solution dissolved in f.

This coating solution was coated onto an aluminum sheet using a Mayer bar so that the dry film thickness was 0.2 μm to prepare a charge generation layer.

Next, the exemplified compound Nα(3)lo is used as a charge transport substance.
g and polycarbonate resin (weight average molecular fi2000
0) was dissolved in 70 g of monochlorobenzene, and this solution was applied onto the charge generation layer using a Mayer bar to form a charge transport layer with a dry film thickness of 20 μm, thereby producing a laminated electrophotographic photoreceptor.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
Using an electrostatic copying paper testing device Model-8P-428, corona charging was carried out statically at 15 KV, and 1
After holding for a second, the illuminance is 204! It was exposed to UV light and its charging characteristics were examined.

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

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, the photoreceptor fabricated in this example was
c) Paste it on the photosensitive drum cylinder of a copying machine (NP-3525, manufactured by Canon) and copy 500 sheets using the same machine. Changes in bright area potential (VL) and dark area potential (VO) at the initial stage and after 5000 copies have been made. was measured. In addition, the initial stage (7)
V, (!: VL was set to -700V and -200V, respectively.The results are shown below.

An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the pigments shown in Table 1 were used.

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

For comparison, an electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that a compound having the following structural formula was used as a charge transport material, and its electrophotographic properties were measured. The results for each are shown below.

Examples 2-10. Comparative Examples 1 to 3 In each of these Examples, Exemplified Compound N was used instead of Exemplified Compound Island (3) as the charge transport substance used in Example 1.
i1 (1), (5), (10), (13), (17)
, (20).

(22), (28), and (30) were used, and the following structural formula comparison compound 2° (described in JP-A-57-195254) was used as a charge generating substance, Eox=0.
98 [V] (Described in JP-A-55-79450) Eox=0.4
0 [V] (Described in JP-A-57-195254) As is clear from the results of Examples and Comparative Examples, the following general formula [! ] Da no noon two -sided B -I row S -ヱ ″ ヱ ヱ ヱ ヱ〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕〕 , the island q-imagawapaa°no, the telephone stand of the face, ? Kasukimata 1 bow for a regular student.

By introducing an electron-donating substituent to Ar and/or Ar2, considerably high sensitivity and durability can be achieved! positional stability can be achieved. By introducing the oxidation potential, the oxidation potential can be lowered to 0.9 [V] or less, and compounds with an oxidation potential of 0.9 [V] or less are obviously highly sensitive, and the potential stability during durability is low. is very good. In addition, when a group with a strong electron donating property is introduced into Arl and/or Ar2 in general formula (1), the sensitivity becomes slightly higher than that of a compound with an oxidation potential in the range of 0.60 [V] to 0.88 [V]. is low (tends to be).

Example 11 A solution prepared by dissolving 5 g of methoxymethylated nylon resin (number average molecular weight 32,000) and alcohol-soluble copolymerized nylon resin (number average molecular weight 29,000) 10 g in 95 g of methanol was applied onto an aluminum substrate using a Meyer knife, and after drying. A subbing layer having a thickness of 1 μm was provided.

Next, 10 g of a charge generating substance represented by the following structural formula, 5 g of butyral resin (degree of butyralization 63 mol%) and 200 g of dioxane were added.
Dispersion was carried out for 48 hours using a ball mill disperser. This dispersion was applied onto the previously produced undercoat layer by a blade coating method to produce a charge generation layer having a thickness of 0.15 μm after drying.

Next, the exemplified compound No. (10) 1Og, polymethyl methacrylate resin (weight average molecular weight 50,000)
10 g of the solution was dissolved in 70 g of monochlorobenzene and coated on the previously formed charge generation layer by a blade coating method to prepare a charge transport layer having a thickness of 19 μm after drying.

A corona discharge of 15 KV was applied to the photoreceptor thus produced. The surface potential at this time was measured (initial potential VO).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 1 second. Sensitivity is 1. The potential v1 after dark decay is %
Exposure amount required to attenuate (EW, μm/crye)
It was evaluated by measuring. At this time, a gallium/aluminum/propylene ternary semiconductor laser (power output: 5 mW; oscillation wavelength: 780 nm) was used as a light source. These results were as follows.

V,: -700V V,: -695V E%'A: 0.53 μJ 7cm"Next, a laser beam printer (LBP-
The photoreceptor was set in a CX (manufactured by Canon), and an actual image forming test was conducted.

The conditions are as follows. -Surface potential knee 7 after next charging
00V, surface potential after image exposure: -150V (exposure amount: 2.0 μJ/c/), transfer potential: +700V, developer polarity: negative polarity, process speed: 50 mm/sec,
Development conditions (development bias): -45'OV, image exposure scan method: image scan, -next pre-charging exposure: 501
Full red exposure at ux*sec and image formation 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. Furthermore, when 3,000 images were printed continuously, stable and good prints were obtained from the initial stage up to 3,000 images.

Example 12 Titanyloxyphthalocyanine log to dioxane 48
The mixture was added to a solution of 5 g of phenoxy resin dissolved in 5 g of phenoxy resin, and dispersed in a ball mill for 2 hours. This dispersion was applied onto an aluminum sheet using a Mayer bar, dried at 80°C for 2 hours, and then dried at 80°C.
A charge generation layer having a thickness of 5 μm was prepared. Next, the exemplified compound N
o, (15) A solution obtained by dissolving 10 g of bisphenol 2 type polycarbonate resin (weight average molecular weight 50,000) in 70 g of monochlorobenzene was applied onto the previously formed charge generation layer using a Mayer bar, and the mixture was heated at 110° C. for 1 hour. It was dried to produce a 19 μm charge transport layer. The thus produced photoreceptor was measured in the same manner as in Example 1'1. The results are shown below.

Vo: -695V V, : -687V E! 4: 0.69 μJ/crrr Example 13 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate, 5 g of Exemplified Compound No. (10) as a charge transport material, and 5 g of polyester resin ( Toluene (weight average molecular weight 49,000)
(parts by weight)-dioxane (50 parts by weight) was mixed with t 00 g of a solution and dispersed in a ball mill for 6 hours. This dispersion was applied onto an aluminum sheet using a Mayer bar and dried at 100° C. for 2 hours to produce a 15 μm photosensitive layer. The photoreceptor thus produced was measured in the same manner as in Example 1. The results are shown below.

Vo: -695V V,: -680V E'4: 1.9Iluxesec (initial) VD: -700V VL: -200V (after 5000 sheets durability) VD: -680V VL: -225V Example 14 Casein on aluminum plate ammonia aqueous solution (casein 1
1 g of 28% ammonia water and 222 ml of water were applied using a Meyer bar to form a subbing layer with a dry thickness of 1 μm. A photoreceptor was prepared in the same manner as in Example 1, except that the charge transport layer and charge generation layer of Example 9 were sequentially laminated thereon, and the layer structure was different, and the charging characteristics were measured in the same manner as in Example 1. did. However, the charging polarity was set to ■. The results are shown below.

■. : Φ695v vl : ■205v E! /S: 2.01uxasec Example 15 Soluble nylon (6-66-610-12
A 5% methanol solution of (quaternary nylon copolymer) was applied to prepare a subbing layer having a dry film thickness of 0.5 μm.

Next, 5 g of a pigment represented by the following structural formula was dispersed in 95 ml of tetrahydrofuran using a sand mill for 200 hours. Next, 5 g of Exemplary Compound No. (28) and bisphenol 2 were added as charge transport substances.
Type polycarbonate resin (weight average molecular weight 50,000
) 10g to 30mj of monochlorobenzene! The solution was added to the previously prepared dispersion and further dispersed using a sand mill for 2 hours. This dispersion was applied onto the previously formed subbing layer using a Mayer bar so that the film thickness after drying would be 20 μm, and then dried. The electrophotographic properties of the photoreceptor thus produced were measured in the same manner as in Example 1.

The results are shown below.

Vo: -690V V,: -675V E'4: 3.1 1ux fist sec [Effects of the Invention] As explained above, the electrophotographic photoreceptor containing the triarylamine compound according to the present invention has high sensitivity, Further, it is possible to provide an electrophotographic photoreceptor with excellent durability and with small fluctuations in bright area potential and dark area potential during continuous image formation by repeated charging and exposure.

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Procedural amendment (voluntary) 1. Display of the case Patent Application No. 330997 of 1988 2, Name of the invention Electrophotographic photoreceptor 3, Name of the person making the amendment Address Name Relationship to the case Patent applicant 3-3O-2 Shimomaruko, Ota-ku, Tokyo (100) Canon Co., Ltd. Company Representative: Keizo Yamaji 44, Agent Address: 3-30-25 Shimomaruko, Ota-ku, Tokyo 146, Specification subject to amendment: Document 6, Contents of amendment: This specification, page 18, lines 2 to 5 In the row, the description [A saturated calomel electrode was obtained] is changed to r, where the reference electrode is the saturated calomel electrode, the counter electrode and the working electrode are P.
t, the electrolyte is 0. IN(n-Bu)4N"CIO: Obtained by sweeping the potential with a potential sweeper using an oxidation potential measuring device that is an acetonitrile solution."

Claims (4)

[Claims] (1) An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a triarylamine compound represented by the following general formula [I]. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ I ] (In the formula, Ar_1 and Ar_2 represent a benzene ring, and at least one has an electron-donating substituent. R_1 and R_2 are hydrogen atoms, (Indicates an alkyl group or an alkoxy group.) (2) The electrophotographic photoreceptor according to claim 1, wherein the triarylamine compound represented by the general formula [I] has an oxidation potential of 0.90 V or less. (3) The electrophotographic photoreceptor according to claim 1, wherein the arylamine compound represented by the general formula [I] has an oxidation potential in the range of 0.60 V to 0.88 V. (4) The electrophotographic photoreceptor according to claim 1, wherein the arylamine compound represented by the general formula [I] has the following structural formulas [II], [III], and [IV]. ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [II] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [III] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [IV]