JP2003280222A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having high potential by electrification and high sensitivity, free of a change in various properties even after repeated use and capable of exhibiting stable performance. <P>SOLUTION: In the electrophotographic photoreceptor having on an electrically conductive support a photosensitive layer containing a charge generating material and a charge transport material as constituent components, a compound represented by formula (1) is contained as the charge transport material and at least one compound selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds is contained in the photosensitive layer, wherein R<SP>1</SP>is alkyl; R<SP>2</SP>is H, alkyl or halogen; and Ar<SP>1</SP>and Ar<SP>2</SP>are each aryl which may have a substituent or a heterocyclic group which may have a substituent. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more specifically, it is characterized by containing a specific compound and a compound selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds. It relates to a photoconductor.

[0002]

2. Description of the Related Art In recent years, the use of electrophotography has spread not only to the field of copying machines but also to fields in which photographic technology has been used in the past, such as printing plate materials, slide films, and microfilm, and lasers, LEDs, and CRTs. Applications to high-speed printers that use a light source are also under consideration. Therefore, the demand for electrophotographic photoreceptors is becoming more sophisticated and wider.
Inorganic photoconductive substances such as selenium, cadmium sulfide, zinc oxide, and silicon have been known as electrophotographic photoreceptors, and have been widely studied and put to practical use. While these inorganic materials have many advantages, they also have various drawbacks. For example, selenium has drawbacks that it is difficult to produce under conditions and is easily crystallized by heat or mechanical shock, and cadmium sulfide and zinc oxide have poor moisture resistance and durability. It has been pointed out that silicon has insufficient chargeability and is difficult to manufacture. Furthermore, selenium and cadmium sulfide have toxicity problems.

On the other hand, organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and are sensitized to a wide range of wavelengths by a suitable sensitizing method. Because of its advantages such as easy body design, its practical application is gradually gaining attention.

By the way, the photosensitive member used in the electrophotographic technique is generally required to have the following basic properties. That is, (1) high chargeability against corona discharge in the dark, (2) little leakage (dark decay) of the obtained charged charge in the dark, and (3) charge charging by light irradiation. The light is rapidly dissipated (4), and (4) there is little residual charge after light irradiation.

However, much research has been conducted on photoconductive polymers such as polyvinylcarbazole as an organic photoconductive substance, but these are not necessarily sufficient in film formability, flexibility and adhesiveness. In addition, it is difficult to say that the photoconductor has the basic properties described above.

On the other hand, regarding the organic low-molecular-weight photoconductive compound, by selecting a binder or the like used for forming the photoconductor, the photoconductor having excellent mechanical strength such as film-forming property, adhesive property and flexibility. However, it is difficult to find a compound suitable for retaining the highly sensitive property.

In order to improve such a point, an organic photoreceptor having higher sensitivity characteristics has been developed, in which different substances have a charge generating function and a charge transporting function. A characteristic of such a photoconductor, which is called a function-separated type, is that materials suitable for each function can be selected from a wide range, and many studies have been carried out because a photoconductor having arbitrary performance can be easily produced. Has been promoted.

Of these, various substances such as phthalocyanine pigments, squarium dyes, azo pigments, and perylene pigments have been investigated as substances in charge of the charge generation function. Among them, azo pigments can have various molecular structures. In addition, since high charge generation efficiency can be expected, it has been widely studied and put into practical use. However, in this azo pigment, the relationship between the molecular structure and the charge generation efficiency has not yet been clarified. The reality is that we are conducting an enormous amount of synthetic research to search for the optimal structure, but those that fully satisfy the basic properties and high durability required for the photoreceptors listed above are , Not yet obtained.

Further, in recent years, laser beam printers and the like, which have advantages of high speed, high image quality and non-impact using laser light as a light source instead of conventional white light, have come into widespread use together with the progress of information processing systems. There is a demand for the development of materials that can meet the demands. Particularly, in recent years, semiconductor lasers, whose applications to compact discs, optical discs and the like have been increased and whose technological progress has been remarkable, have been actively applied in the printer field as compact and highly reliable light source materials. In this case, since the wavelength of the light source is around 780 nm, a photoconductor having high sensitivity to long wavelength light around 780 nm is suitable, and its development is strongly desired. Among them, particularly, a photoconductor using phthalocyanine having light absorption in the near infrared region has been actively developed, but a satisfactory one has not been obtained yet.

On the other hand, there are a hole transporting substance and an electron transporting substance as the substances in charge of the charge transporting function. Various substances such as hydrazone compounds and styryl compounds are considered as hole transporting substances, and various substances such as 2,4,7-trinitro-9-fluorenone and diphenoquinone derivatives are considered as electron transporting substances.
Although it is being put to practical use, the fact is that it is also conducting an enormous amount of synthetic research to search for the optimal structure. In fact, many improvements have been made so far, but none of them have sufficiently obtained the basic properties and high durability required for the above-mentioned photoreceptor.

Further, in putting the electrophotographic photosensitive member to practical use, the repeated stability of the photosensitive member is also a requirement that cannot be ignored. By repeatedly using the photoconductor, various phenomena that cause image defects (background fogging, black spots, image defects, etc.) such as a decrease in charging potential, a decrease in sensitivity, and an increase in residual potential appear. For the purpose of suppressing these, various substances to be added to the photosensitive layer have been studied, but the effect differs depending on the type and combination of the charge generating substance and the charge transporting substance, and it is necessary to search for a structure that can withstand practical use. It's a difficult situation.

As described above, various improvements have been made in the production of electrophotographic photoconductors, but the basic properties and high durability required for the photoconductors listed above are sufficiently satisfied. The current situation is that nothing has been obtained yet.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member which has a high charging potential and high sensitivity, and which can exhibit stable performance without changing various characteristics even after repeated use. .

[0014]

Means for Solving the Problems As a result of research conducted by the inventors to achieve the above object, Japanese Patent Application No. 2001-3271
By using a compound having a specific structure described in No. 73 and at least one compound selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds in combination, a photoreceptor having extremely good sensitivity and durability can be obtained. The inventors have found that they can be obtained and have completed the present invention. Here, the compound having a specific structure is a compound represented by the following general formula (1).

[0015]

[Chemical 2]

In the general formula (1), R ¹ represents an alkyl group and R ² represents a hydrogen atom, an alkyl group or a halogen atom. Ar ¹ and Ar ² each represent an aryl group or a heterocyclic group which may have a substituent.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the general formula (1), specific examples of R ¹ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group. Linear alkyl group such as isopropyl group, sec-butyl group, tert-butyl group, isobutyl group, isopentyl group, neopentyl group, tert.
-Pentyl group, 1-methylbutyl group, 1-ethylpropyl group, 2-methylbutyl group, 1,2-dimethylpropyl group, isohexyl group, 1-methypentyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1 -Ethyl-2
-Methylpropyl group, 1,1-dimethylbutyl group, 2-
Methylpentyl group, 3-methylpentyl group, 1,2-dimethylbutyl group, 1-ethyl-1-methylpropyl group,
Branched alkyl groups such as 2,2-dimethylbutyl group, 1,2,2-trimethylpropyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, and 1,1,2-trimethylpropyl group, Examples thereof include a cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group, and an alkyl group in which the above-described linear alkyl group, branched alkyl group, and cycloalkyl group are further bonded. . Specific examples of R ² include a hydrogen atom, the above-mentioned alkyl group, a halogen atom such as a fluorine atom, a bromine atom, a chlorine atom and an iodine atom.

Specific examples of Ar ¹ and Ar ² are:
Aryl group such as phenyl group and naphthyl group, pyridyl group,
Heterocyclic groups such as thienyl group and furyl group can be mentioned. Ar ¹ and Ar ² may have a substituent, and specific examples thereof include the above-mentioned alkyl group and halogen atom.

Specific examples of the compound represented by the general formula (1) according to the present invention are shown below, but the invention is not limited thereto.

[0020]

[Chemical 3]

[0021]

[Chemical 4]

[0022]

[Chemical 5]

[0023]

[Chemical 6]

[0024]

[Chemical 7]

[0025]

[Chemical 8]

[0026]

[Chemical 9]

[0027]

[Chemical 10]

[0028]

[Chemical 11]

[0029]

[Chemical 12]

[0030]

[Chemical 13]

[0031]

[Chemical 14]

[0032]

[Chemical 15]

The compound represented by the general formula (1) according to the present invention can be produced by the method described in Japanese Patent Application No. 2001-327173 already proposed.

Specific examples of the hydroquinone compound used in the present invention include hydroquinone, methylhydroquinone, 2,3-dimethylhydroquinone, 2,5-dimethylhydroquinone, trimethylhydroquinone, 2,
5-diamylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, chlorohydroquinone, 2,5-dioctylhydroquinone, 2-tert-butyl-5-methylhydroquinone, methoxyhydroquinone, 2-methyl- 5-chlorohydroquinone, 1,4-naphthalenediol,
5,10-anthracene diol etc. are mentioned.

Specific examples of the hindered phenol compound used in the present invention include 3,5-di-tert-butyl-4-hydroxytoluene and 2,2'-methylenebis (6-tert-butyl-4-methylphenol). ),
4,4'-butylidene bis (6-tert-butyl-3
-Methylphenol), 4,4'-thiobis (6-te
rt-butyl-3-methylphenol), 2,2′-thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,
6-hexanediol bis [3- (3,5-di-ter
t-butyl-4-hydroxyphenyl) propionate], pentaerythrityl tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,5-di-tert-butyl-4- Examples thereof include hydroxyanisole.

Specific examples of the tocopherol compound used in the present invention include generally known α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, etc., as well as calcium tocopherol acetate, tocopherol succinate, and tocopherol succinate. Various derivatives such as salts can also be used.

Further, the combined use of two or more of the above hydroquinone compound, hindered phenol compound and tocopherol compound can further enhance the effect.

The electrophotographic photosensitive member of the present invention is obtained by containing the compound represented by the general formula (1), the charge generating substance, and at least one selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds. . Examples of the charge generation substance include metals such as selenium and cadmium, perylene compounds such as perylene anhydride, and perylene imide, anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, and anthraquinone pigments such as violanthrone derivatives, or polyvalent compounds. Ring quinone pigment, metal phthalocyanine,
A phthalocyanine compound such as a metal-free phthalocyanine, a metal naphthalocyanine, a naphthalocyanine compound such as a metal-free naphthalocyanine, a porphyrin pigment, a quinacridone pigment, a cyanine dye, an azurenium dye, and an azo compound are also used. Among these, those using bisazo compounds, trisazo compounds, phthalocyanine compounds,
It is preferable because it provides a high-sensitivity photoconductor with high carrier generation efficiency.

There are various types of photoreceptors, and any of them can be used. For example, a single-layer type photoreceptor in which a charge generating substance, a charge transporting substance, and a photosensitive layer made of a film-forming binder resin are provided on a conductive support,
An example is a laminated type photoreceptor in which a charge generating layer composed of a charge generating substance and a binder resin and a charge transporting layer composed of a charge transporting substance and a binder resin are provided on a conductive support. Either the charge generation layer or the charge transport layer may be the upper layer. If necessary, an undercoat layer may be provided between the conductive support and the photosensitive layer, an overcoat layer may be provided on the surface of the photoreceptor, and an intermediate layer may be provided between the charge generation layer and the charge transport layer in the case of a laminated type photoreceptor. Can be provided. As a support for producing a photoconductor using the compound of the present invention, a metal drum, a metal plate, a conductive paper, a sheet of plastic film, a drum-shaped or belt-shaped support and the like are used. .

As the film-forming binder resin used for forming the photosensitive layer on those supports, various resins can be mentioned depending on the field of use. For example, in the application of photoconductor for copying, polystyrene resin, polyvinyl acetal resin, polyvinyl butyral resin, polysulfone resin, polycarbonate resin, vinyl acetate / crotonic acid copolymer resin,
Examples thereof include polyester resins, polyphenylene oxide resins, polyarylate resins, alkyd resins, acrylic resins, methacrylic resins, and phenoxy resins. Among these, polystyrene resin, polyvinyl acetal resin, polyvinyl butyral resin, polycarbonate resin, polyester resin, polyarylate resin and the like are excellent in potential characteristics as a photoreceptor. Further, these resins may be used alone or as a copolymer by mixing one kind or two or more kinds. The amount of these binder resins added to the photoconductive compound is 20 to 1000% by mass.
Is preferable, and 50-500 mass% is more preferable.

In the case of a laminated type photoreceptor, these resins contained in the charge generating layer are contained in an amount of 10 to 50 relative to the charge generating substance.
0 mass% is preferable, and 50-150 mass% is more preferable. If the ratio of the resin is too high, the charge generation efficiency is lowered, and if the ratio of the resin is too low, the film formability becomes a problem. The content of these resins contained in the charge transport layer is preferably 20 to 1000% by mass, more preferably 50 to 500% by mass, based on the charge transport substance. If the ratio of the resin is too high, the sensitivity is lowered, and if the ratio of the resin is too low, the repeating characteristics may be deteriorated or the coating film may be damaged.

Some of these resins include pulling, bending,
Some have weak mechanical strength such as compression. To improve this property, plasticizing agents can be added. Specifically, phthalate ester (for example, DOP, D
BP, etc., phosphoric acid ester (eg TCP, TOP
Etc.), sebacic acid ester, adipic acid ester, nitrile rubber, chlorinated hydrocarbon and the like. If these substances are added more than necessary, the electrophotographic characteristics are adversely affected, so the proportion thereof is preferably 20% or less relative to the binder resin.

In the case of a laminated type photoreceptor, the hydroquinone compound, the hindered phenol compound used in the present invention,
The tocopherol compound may be contained in either the charge generation layer or the charge transport layer. When it is contained in the charge transport layer together with the compound represented by the general formula (1), the effect of suppressing the increase in residual potential is high, and when it is contained in the charge generation layer together with the charge generating substance, the charging potential is deteriorated. There is a suppressing effect.

In addition, as an additive to the photoreceptor, an anti-curl agent or the like, and a leveling agent or the like for improving the coating property can be added if necessary.

The compound represented by the general formula (1) can be used in combination with other charge transport materials. The charge transport material includes a hole transport material and an electron transport material. Examples of the former include oxadiazoles disclosed in JP-B-34-5466 and JP-B-45-555.
Such as triphenylmethanes disclosed in Japanese Patent Publication No. 52-4188, etc.,
Examples thereof include the hydrazones disclosed in JP-B-55-42380 and the oxadiazoles disclosed in JP-A-56-123544. On the other hand, examples of the electron transport material include chloranil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,
7-trinitro-9-fluorenone, 2,4,5,7-
Tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 1,3,7-trinitrodibenzothiophene, 1,3,7-trinitrodibenzothiophene- 5,
5-dioxide and the like. These charge transport materials may be used alone or in combination of two or more.

Further, a certain electron-withdrawing compound may be added as a sensitizer which forms a charge transfer complex with the compound represented by the general formula (1) and further enhances the sensitizing effect. Examples of the electron-withdrawing compound include quinones such as 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, phenanthrenequinone, and 4-nitro. Aldehydes such as benzaldehyde, 9
-Benzoylanthracene, indandione, 3,5-
Ketones such as dinitrobenzophenone, 3,3 ′, 5,5′-tetranitrobenzophenone, phthalic anhydride, 4
Acid anhydrides such as chloronaphthalic anhydride, terephthalalmalononitrile, 9-anthrylmethylidene malononitrile, 4-nitrobenzalmalononitrile, 4- (p-
Cyano compounds such as (nitrobenzoyloxy) benzalmalononitrile, 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,5,6,7- Examples thereof include phthalides such as tetrachlorophthalide.

The charge-generating substance and the charge-transporting substance are dissolved or dispersed in a suitable solvent together with various additives according to the form of the photoreceptor, and the coating solution is coated on the above-mentioned conductive support. Then, the photoconductor can be manufactured by drying.

As the coating solvent, chloroform, 1,2-
Dichloroethane, dichloromethane, trichloroethane,
Halogenated hydrocarbons such as trichloroethylene, chlorobenzene and dichlorobenzene, aromatic hydrocarbons such as benzene, toluene and xylene, 1,3-dioxolane, 1,
4-dioxane, tetrahydrofuran, methyl cellosolve, ethyl cellosolve, ether solvents such as ethylene glycol dimethyl ether, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone and cyclohexanone, esters such as ethyl acetate, methyl formate, methyl cellosolve acetate System solvent,
N, N-dimethylformamide, acetonitrile, N-
Examples include aprotic polar solvents such as methylpyrrolidone and dimethyl sulfoxide, alcoholic solvents and the like. These solvents can be used alone or as a mixed solvent of two or more kinds.

[0049]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 Polyvinyl butyral resin (manufactured by Sekisui Chemical; BM-1)
1.0 g was dissolved in 100 g of 1,3-dioxolane,
1.5 g of titanyloxyphthalocyanine (manufactured by Sanyo Dye Co .; T-22S) was mixed as a charge generating substance, and dispersed for 4 hours together with low alkali glass beads having a diameter of 1 mm by a paint conditioner device manufactured by Red Devil. The thus obtained dispersion liquid was applied onto a thin aluminum metal plate (JIS standard # 1050) with an applicator and dried to form a charge generation layer having a thickness of about 0.2 μm.
Next, 10 g of Exemplified compound (31), 10 g of polycarbonate (manufactured by Teijin Chemicals; Panlite K-1300), te
0.2 g of rt-butylhydroquinone was dissolved in 200 g of tetrahydrofuran, and this solution was applied onto the charge generation layer with an applicator and dried to give a film thickness of about 20 μm.
Was formed on the charge transport layer.

An electrostatic recording tester (Kawaguchi Electric Co .; EPA-820) was used for the thus prepared laminated type photoreceptor.
0) was used to evaluate electrophotographic characteristics. Measurement condition:
Applied voltage -6 kV, static No. 3 (turntable rotation speed mode: 10 m / min). As a result, the charging potential (Vo) was -790 V and the residual potential (Vr).
Shows a high sensitivity value of −8 V and a half-exposure amount (E1 / 2) of 0.8 lux · sec.

Further, using the same apparatus, characteristic evaluation was carried out for repeated use in which one cycle of charging-discharging (eliminating light: irradiation with white light of 400 lux × 1 second) was set as one cycle. 500
When the changes in the charging potential and the residual potential due to the repetition of 0 times were obtained, the first charging potential (Vo) -790V,
The residual potential (Vr) is -8V, and the 5000th charging potential (Vo) is -785V and the residual potential (Vr) is -12V.
And showed stable characteristics with no change in potential due to repetition. In addition, the first half exposure (E1 / 2) 0.8
5,000th half-exposure dose (E1 /
2) showed excellent characteristics with no change of 0.8 lux.sec.

Examples 2 to 31 Instead of the exemplary compound (31) which is the charge transporting substance of Example 1 and the tert-butylhydroquinone which is the additive, the charge transporting substances and the additives shown in Table 1 and Table 2 are used, respectively. A photoreceptor was prepared in the same manner as in Example 1 except that it was used, and its characteristics were evaluated. The results are shown in Tables 3 and 4.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

[0057]

[Table 4]

Example 22 Metal-free phthalocyanine (manufactured by Toyo Ink Mfg. Co .; TPA-8)
91) 1 g and 40 g of tetrahydrofuran were treated with a paint conditioner manufactured by Red Devil Co. to have a diameter of 1 m.
m low alkali glass beads were dispersed for 4 hours. In the dispersion liquid thus obtained, the exemplified compound (31) 2.5
g, polycarbonate resin (PCZ-200; Mitsubishi Gas Chemical Co., Ltd.) 10 g, tert-butyl hydroquinone 0.
After adding 05 g and 60 g of tetrahydrofuran, the dispersion was further treated with a paint conditioner device for 30 minutes, and then coated on aluminum vapor-deposited polyester with an applicator and dried to form a photoconductor having a film thickness of about 15 μm. The electrophotographic characteristics of this photoreceptor were evaluated in the same manner as in Example 1. However, only the applied voltage was changed to +5 kV. As a result, the first charge potential (Vo) + 395V, the residual potential (Vr) + 7V, the half-exposure amount (E1 / 2) 1.3 lux · sec, and the charge potential (Vo) +39 after 5000 times of repetition.
0V, residual potential (Vr) + 11V, half exposure amount (E1 /
2) It showed excellent characteristics of 1.3 lux · sec with high sensitivity and little change.

Examples 23 to 42 Exemplified compound (31) which is the charge transport material of Example 22,
A photoreceptor was prepared in the same manner as in Example 22 except that the charge-transporting substances and the additives shown in Tables 1 and 2 were used instead of the additive tert-butylhydroquinone, and the characteristics thereof were evaluated. . The results are shown in Tables 5 and 6.

[0060]

[Table 5]

[0061]

[Table 6]

Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1 except that the comparative compound (54) shown below was used as the charge transporting material instead of the exemplified compound (31), and its characteristics were evaluated. as a result,
The first charging potential (Vo) is −755 V, and the residual potential (V
r) is -57V, the half-exposure amount (E1 / 2) is 2.4 lux · sec, which is low in sensitivity, and the 5000th charging potential (V
o) was -610 V, the residual potential (Vr) was -134 V, and the half-dose exposure amount (E1 / 2) was 2.7 lux · sec, and a large change in potential was observed with repetition.

[0063]

[Chemical 16]

Comparative Example 2 A photoconductor was prepared in the same manner as in Example 1 except that the comparative compound (55) shown below was used as the charge transporting material instead of the exemplified compound (31), and its characteristics were evaluated. as a result,
The first charging potential (Vo) is -745 V, and the residual potential (V
r) was -38 V and the half-exposure amount (E1 / 2) was 1.2 lux · sec, which were relatively good results, but the 5000th charging potential (Vo) was -335 V, and the residual potential (Vr) was −
At 92 V, the half-exposure amount (E1 / 2) was 1.3 lux · sec, and a large change in potential was observed with repetition.

[0065]

[Chemical 17]

Comparative Example 3 A photoconductor was prepared in the same manner as in Example 1 except that the additive tert-butylhydroquinone was not used, and its characteristics were evaluated. As a result, the first charge potential (Vo) was -790 V, the residual potential (Vr) was -21 V, and the half-exposure amount (E1 / 2) was 0.9 lux · sec, which were relatively good results. The 5000th charge potential (Vo) is -645.
V, residual potential (Vr) is -96 V, half exposure (E1 /
2) was 1.1 lux · sec, and a large change in the electric potential was observed with repetition.

Comparative Example 4 A photoconductor was prepared in the same manner as in Example 22 except that the comparative compound (54) was used as the charge transporting material instead of the exemplified compound (31), and the characteristics thereof were evaluated. As a result, the first charging potential (Vo) is + 325V and the residual potential (Vr) is +.
82V, half-exposure (E1 / 2) is 3.5 lux · sec, which is low sensitivity, and the charging potential (Vo) at the 5000th time is +
The residual potential (Vr) was 225 V, the residual potential (Vr) was +121 V, and the half-dose exposure amount (E1 / 2) was 3.8 lux · sec.

Comparative Example 5 A photoconductor was prepared in the same manner as in Example 22 except that the comparative compound (55) was used as the charge transporting material in place of the exemplified compound (31), and its characteristics were evaluated. As a result, the first charging potential (Vo) is + 355V and the residual potential (Vr) is +.
32V, the half exposure (E1 / 2) was 1.6 lux · sec, which was a relatively good result, but the 5000th charging potential (Vo) was + 225V, and the residual potential (Vr) was +102.
V and half-exposure amount (E1 / 2) were 1.8 lux · sec, and a large change in potential was observed with repetition.

Comparative Example 6 A photoreceptor was prepared in the same manner as in Example 22 except that the additive tert-butylhydroquinone was not used, and its characteristics were evaluated. As a result, the first charging potential (V
o) was +380 V, residual potential (Vr) was +24 V, and half-exposure amount (E1 / 2) was 1.4 lux · sec, which were relatively good results, but the 5000th charging potential (Vo) was +.
The residual potential (Vr) was 255 V, the residual potential (Vr) was +103 V, and the half-dose exposure amount (E1 / 2) was 1.5 lux · sec.

From these results, when the compound represented by the general formula (1) is used as the charge transport material and at least one compound selected from the hydroquinone compound, the hindered phenol compound and the tocopherol compound is used as the additive, high sensitivity and high sensitivity are obtained. It was found that a durable electrophotographic photoreceptor can be obtained.

[0071]

As is apparent from the above, according to the present invention, it is possible to provide an electrophotographic photosensitive member having high sensitivity and high durability.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H068 AA14 AA20 AA34 AA35 BA01                       BA12 BA13

Claims (4)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer containing a charge generating substance and a charge transporting substance as constituent components on a conductive support, containing a compound represented by the following general formula (1) as a charge transporting substance: An electrophotographic photosensitive member characterized in that the photosensitive layer contains at least one compound selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds. [Chemical 1] (In the general formula (1), R ¹ represents an alkyl group, R ²
Represents a hydrogen atom, an alkyl group or a halogen atom.
Ar ¹ and Ar ² each represent an aryl group or a heterocyclic group which may have a substituent. ) 2. A laminate type photoreceptor comprising a conductive support and at least a charge generation layer and a charge transport layer laminated on the conductive support,
The charge transport layer contains an enamine compound represented by the general formula (1) as a charge transport substance, and the charge transport layer contains at least one compound selected from a hydroquinone compound, a hindered phenol compound and a tocopherol compound. Characteristic electrophotographic photoreceptor. 3. A laminate type photoreceptor comprising a conductive support and at least a charge generation layer and a charge transport layer laminated on the conductive support,
The charge transport layer contains a compound represented by the above general formula (1) as a charge transport material, and the charge generation layer contains at least one compound selected from a hydroquinone compound, a hindered phenol compound and a tocopherol compound. An electrophotographic photosensitive member. 4. A photoconductor having a photosensitive layer containing at least a charge-generating substance and a charge-transporting substance on a conductive support directly or via an undercoat layer, wherein the above-mentioned general formula ( 1) containing a compound
An electrophotographic photoreceptor containing at least one compound selected from hydroquinone compounds, hindered phenol compounds and tocopherol compounds.