JP2000204083A - New stilbenequinone compound, electrophotographic photoreceptor and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound excellent in compatibility with resin binders, also excellent in electron transporting ability and useful for photosensitive layers of electrophotographic photoreceptors in which photosensitive layers are provided on an electroconductive substrate. SOLUTION: This compound is represented by formula I [one or more groups of R1 to R4 are each a group of formula II or the like and the residual R1 to R4, R5 to R8 are each H, a halogen, a (substituted)1-12C alkyl or the like; R9 to R12 are each H, a halogen or a 1-6C alkyl], e.g. a compound of formula III. The compound of formula I is obtained by reacting, e.g. the corresponding phenolic compound of formula IV and V (e.g. 2-tert-butyl-4,6-dimethylphenol) in an organic solvent such as chloroform, in the presence of an oxidizing agent such as potassium permanganate. The compound is used as an electrophotographic photoreceptor to provide the objective electrophotographic photoreceptor excellent in electrical characteristics and repeated stability and having high endurance. The photoreceptor is useful for electrophotographic devices such as printers and copying machines using electrophotographic systems.

Description

DETAILED DESCRIPTION OF THE INVENTION

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel electron transport material, an electrophotographic photoreceptor using the same, and an electrophotographic apparatus using the electrophotographic photoreceptor. .

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2. Description of the Related Art In recent years, electrophotographic photoreceptors using an organic photoconductive material have been designed so that the characteristics of the photoreceptor can be variously designed in consideration of pollution-free, low cost, and freedom of material selection. In view of this, many have been proposed and put into practical use.

The photosensitive layer of an organic electrophotographic photoreceptor mainly comprises a layer in which an organic photoconductive material is dispersed in a resin, and a layer in which a charge generating material is dispersed in a resin (a charge generating layer) and a charge transporting material in a resin. There are proposed a multilayer structure in which a layer (charge transport layer) dispersed in a monolayer is laminated, and a single-layer structure in which a charge generation material and a charge transport material are combined and dispersed in a resin.

[0004] Above all, a function-separated type photosensitive member in which a charge transport layer is laminated on a charge generating layer as a photosensitive layer has excellent photosensitive member characteristics and durability, and has been widely put to practical use. Since the hole transporting material is usually used for the charge transport layer provided on the function-separated type photoreceptor, the photoreceptor is used in an electrophotographic apparatus that operates in a negative charging process.
The negative corona discharge used in the negative charging process is unstable and generates a large amount of ozone compared to the positive one, so it has a problem of adverse effects on the photoconductor and the use environment. ing. In order to solve these problems, an organic electrophotographic photoreceptor that can be used in a positive charging process is effective. By the way, in order to make the photosensitive member having excellent durability as described above for the positive charging process and high sensitivity, it is necessary to use a substance having an excellent electron transport function. Such substances have hitherto been disclosed, for example, in Japanese Patent Laid-Open No. 1-20634.
9, JP-A-3-290666, JP-A-4-360148, Journal of the Society of Electrophotography Vol.30, p266
273 (1991).

[0005] Also, in a negatively charged organic electrophotographic photoreceptor, in order to prevent deterioration due to repeated use and to improve electrical characteristics, an electron accepting substance having an electron transporting property is contained in the photosensitive layer, In order to smoothly transfer the electric charge to the conductive substrate, the undercoating layer may contain an electron transporting substance such as a diphenoquinone compound, as disclosed in JP-A-5-113683 and JP-A-6-27693. JP-A-2-300759, JP-A-3-8
No. 1776, Japanese Patent Application Laid-Open No. 3-216662, and the like.

[0006]

However, the diphenoquinone compounds and stilbenequinone compounds described in the above publications do not sufficiently satisfy the electrical characteristics such as sensitivity and residual potential, and do not provide a photosensitive layer or an undercoat layer. Since the compatibility with the resin binder therein is low, there are problems such as precipitation. In order to solve this problem, the content of the diphenoquinone compound in the photosensitive layer is limited, and as a result, it has been difficult to obtain a photosensitive member having excellent electron transporting ability.

Accordingly, an object of the present invention is to provide a photosensitive member for electrophotography having a photosensitive layer on a conductive substrate, which eliminates the above-mentioned disadvantages, has excellent compatibility with a resin binder, and further has an electron transporting ability. An object of the present invention is to provide an excellent novel stilbenequinone compound. Another object of the present invention is to provide an electrophotographic photoreceptor which has excellent electrical properties and is stable even when used repeatedly by using the novel compound, and an electrophotographic apparatus using the electrophotographic photoreceptor. It is in.

[0008]

In order to solve the above-mentioned problems, a novel stilbenequinone compound of the present invention has the following general formula (I): (Wherein at least one of R ^{1 to} R ⁴ is a group represented by the following general formula (II): (Wherein, R ^{9 to} R ¹² each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms), and the remaining R ^{1 to} R ⁴ and R ⁵ ~ R
⁸ independently has a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a halogenated alkyl group, a cyclic alkyl group which may have a substituent, and a substituent. An optionally substituted aryl group, an optionally substituted heterocyclic group, an optionally substituted aralkyl group,
To 6 alkoxy groups, halogenated alkoxy groups, or the following general formula (III): Or two groups may combine to form a cyclic alkyl group which may have a substituent or an aromatic ring which may have a substituent) It is characterized by the following.

The novel stilbenequinone compound of the present invention is
Both have better compatibility with resin binders than conventional diphenoquinone compounds and stilbenequinone compounds,
Also excellent in electron transport ability.

The electrophotographic photoreceptor of the present invention is characterized in that the electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate contains the stilbenequinone compound in the photosensitive layer. By including the novel stilbenequinone compound of the present invention in the photosensitive layer of the photoreceptor, the electron transportability is improved, and excellent electrical properties are exhibited. At the same time, the charge trap is reduced, and the effect of excellent repetition stability is obtained. To play. Further, in the present invention, the photosensitive layer can be suitably applied to a photosensitive member in which the photosensitive layer is a single-layer type photosensitive layer.

Further, another electrophotographic photoconductor of the present invention is an electrophotographic photoconductor in which an undercoat layer and a photosensitive layer are sequentially provided on a conductive substrate, wherein the stilbene is provided in the undercoat layer. It is characterized by containing a quinone compound. By including the novel stilbenequinone compound of the present invention in the undercoat layer of the photoreceptor, electrons generated in the photosensitive layer are easily injected into the conductive substrate, and the trapping of charges in the photosensitive layer is reduced, and Even when the photoreceptor is repeatedly used, the trapping of charges in the photosensitive layer is reduced, and the effect of excellent repetition stability is exhibited.

In the photoreceptor of the present invention, the photosensitive layer contains
The following general formula (IV) as a hole transport material, (Wherein, R ^{13 to} R ⁴⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms).

An electrophotographic apparatus according to the present invention is provided with the electrophotographic photosensitive member.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The novel stilbenequinone compound of the present invention can be synthesized by a known synthesis method (J. Org. Chem., 1995, 50, 3927 or
J. Chin. Chem. Soc. (Taipei), 1989, 36, 219)
For example, it can be synthesized according to the following reaction formula.

That is, as shown in the above reaction formula (A), a phenolic compound is dissolved in an organic solvent such as chloroform, dichloromethane, benzene and the like, and is dissolved with an oxidizing agent such as potassium permanganate, potassium ferricyanide and manganese dioxide. It can be synthesized by an oxidation reaction.

Specific examples of the novel stilbenequinone compound represented by the general formula (I) are shown below, but are not limited to these compounds. In the following, [III] is the following general formula (III), Represents a group represented by

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Embodiments of the electrophotographic photoreceptor of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual sectional view showing one embodiment of the photoreceptor of the present invention, wherein 1 is a conductive substrate, 2 is an undercoat layer, 3 is a photosensitive layer, 4 is a protective layer,
The undercoat layer 2 and the protective layer 4 are provided as necessary.
The photosensitive layer 3 has both a charge generation function and a charge transport function, and includes a single layer type having both functions in one layer, and a function separation type in which the charge generation layer and the charge transport layer are separated. As a specific example, there is a photoconductor having a layer configuration as shown in FIGS. FIG. 2 shows a photoconductor in which the photosensitive layer 3 is a single-layer type. FIG. 3 shows that the photosensitive layer 3 has a charge generation layer 3a,
This is a function-separated-type laminated photoconductor in which charge transport layers 3b are laminated in this order. FIG. 4 shows a function-separated-type laminated photoconductor in which a photosensitive layer is laminated in the order of a charge transport layer 3b and a charge generation layer 3a and has a protective layer 4.

The conductive substrate 1 serves not only as an electrode of the photoreceptor but also as a support for the other layers, and may be cylindrical, plate-like or film-like. Alternatively, a conductive material may be applied to a metal such as nickel, glass, resin, or the like.

The undercoat layer 2 can be provided as necessary, and is made of a layer mainly composed of a resin, an oxide film such as alumite, etc., and prevents injection of unnecessary charges from the conductive substrate into the photosensitive layer. It is provided as needed for the purpose of covering defects on the surface of the substrate, improving the adhesion of the photosensitive layer, and the like. As a resin binder for the undercoat layer, polycarbonate resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, polyethylene, polypropylene, polystyrene, acrylic resin,
Polyurethane resin, epoxy resin, melamine resin, silicone resin, polyamide resin, polystyrene resin, polyacetal resin, polyarylate resin, polysulfone resin, methacrylic acid ester polymer and their copolymers can be used in appropriate combination It is. In the resin binder, metal oxides such as silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), and zirconium oxide; metal sulfides such as barium sulfide and calcium sulfide;
Metal nitrides such as silicon nitride and aluminum nitride, metal oxide fine particles and the like may be contained.

In the case of an undercoat layer containing a resin as a main component, the novel stilbenequinone compound of the present invention can be contained for the purpose of imparting electron transport properties and reducing charge traps. The content is 0.1% with respect to the solid content of the undercoat layer.
-60% by weight, preferably 5-40% by weight.

Although the thickness of the undercoat layer depends on the composition of the undercoat layer, it can be arbitrarily set within a range where adverse effects such as an increase in residual potential do not occur when repeatedly used continuously.

In the case of the function separation type, the photosensitive layer 3 mainly comprises two layers of a charge generation layer 3a and a charge transport layer 3b.
In the case of a single layer type, it is composed of one layer.

The charge generation layer 3a is formed by vacuum deposition of an organic photoconductive substance or application of a material in which particles of the organic photoconductive substance are dispersed in a resin binder, and generates charges by receiving light. . In addition, it is important that the charge generation efficiency is high, and at the same time, the injected property of the generated charge into the charge transport layer 3b is important.

Since the charge generation layer only needs to have a charge generation function, its thickness is determined by the light absorption coefficient of the charge generation material, and is generally 5 μm or less, preferably 1 μm or less.

The charge generation layer may be composed of a charge generation substance as a main component and a charge transport substance added thereto. Phthalocyanine pigments as charge generating substances,
Azo pigments, anthrone pigments, perylene pigments, perinone pigments, squarylium pigments, thiapyrylium pigments,
Quinacridone pigments and the like can be used, and these pigments may be used in combination. In particular, disazo pigments and trisazo pigments as azo pigments, and N, N'-bis (3,5-dimethylphenyl)-as perylene pigments
As 3,4: 9,10-perylene bis (carboximide) and phthalocyanine pigments, metal-free phthalocyanine, copper phthalocyanine, and titanyl phthalocyanine are preferable, and further, X-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, and ε-type copper Phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, Y
Type titanyl phthalocyanine, amorphous titanyl phthalocyanine, and titanyl phthalocyanine having a Bragg angle 2θ of 9.6 ° as the maximum peak in a CuKα: X-ray diffraction spectrum described in JP-A No. 8-209023 are preferred.

As the resin binder for the charge generation layer,
Polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, silicone resin, polycarbonate resin, polyester resin, polyethylene, polypropylene, polystyrene, acrylic resin, polyurethane resin, epoxy resin, melamine resin,
A polyamide resin, a polystyrene resin, a polyacetal resin, a polyarylate resin, a polysulfone resin, a polymer of methacrylic acid ester, a copolymer thereof, or the like can be used in an appropriate combination.

The charge transport layer 3b is a coating film made of a material in which a charge transport material is dispersed in a resin binder. The charge transport layer 3b retains the charge of the photosensitive member as an insulator layer in a dark place, and is injected from the charge generation layer at the time of receiving light. It exerts the function of transporting the charged electric charge.

As the charge transporting substance, the compound represented by the above general formula (IV) is preferable as the hole transporting substance. In addition, hydrazone compounds, pyrazoline compounds, pyrazolone compounds, oxadiazole compounds, oxazole compounds Compound, arylamine compound, benzidine compound, stilbene compound, styryl compound, polyvinyl carbazole, hole transport substance such as polysilane, or a novel stilbene quinone compound which is a novel electron transport substance of the present invention, succinic anhydride, maleic anhydride, dibromo Succinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride, 4-
Nitrophthalic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, trimellitic anhydride, phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanil, o-nitrobenzoic acid, Trinitrofluorenone, quinone, benzoquinone, diphenoquinone, naphthoquinone,
Electron acceptors such as anthraquinone and stilbenequinone,
Electron transport materials can be used, and these charge transport materials can be used alone or in combination of two or more. As the compound represented by the general formula (IV), for example, compounds represented by the following structural formulas (IV-1) to (IV-136) are used. The compounds having the structural formulas represented by (V-1) to (V-76) are used, but the present invention is not limited thereto.

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As the resin binder for the charge transport layer,
Polycarbonate resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, polyethylene, polypropylene, polystyrene, acrylic resin, polyurethane resin,
Epoxy resin, melamine resin, silicone resin, silicone resin, polyamide resin, polystyrene resin, polyacetal resin, polyarylate resin, polysulfone resin, methacrylic acid ester polymer and copolymers thereof may be used in appropriate combination. It is possible. In particular, the structural units (VI-1) to (VI-
Polycarbonate resins and polyester resins having one or more of the above 7) are suitable.
You may mix and use more than one kind.

[0070]

The thickness of the charge transport layer is preferably in the range of 3 to 50 μm, more preferably 10 to 40 μm, in order to maintain a practically effective surface potential.

In the case of a single-layer type photosensitive layer, as a main component,
There are a charge generation material used for the charge generation layer 3a and the charge transport layer 3b, a charge transport material and a resin binder, and a charge generation material and a resin binder.

The thickness of the single-layer type photosensitive layer is preferably in the range of 3 to 50 μm, more preferably 10 to 40 μm, in order to maintain a practically effective surface potential.

In these photosensitive layers, for the purpose of improving environmental resistance and stability against harmful light, a deterioration inhibitor such as an antioxidant and a light stabilizer can be contained. Compounds used for such purposes include chromanol derivatives and esterified compounds such as tocopherol, polyarylalkane compounds, hydroquinone derivatives, etherified compounds, dietherified compounds, benzophenone derivatives, benzotriazole derivatives, thioether compounds, phenylenediamine derivatives , Phosphonate esters, phosphite esters, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like.

Further, the photosensitive layer may contain a leveling agent such as silicone oil or fluorine-based oil for the purpose of improving the leveling property of the formed film and imparting lubricity.

Furthermore, the novel stilbene quinone compound of the present invention, which is an electron accepting substance and an electron transporting substance, can be contained in the photosensitive layer for the purpose of imparting electron transporting property and reducing charge trapping. The content is 0.1 to 90% by weight, preferably 5 to 60% by weight, based on the solid content of each layer of the photosensitive layer.

Further, if necessary, other electron accepting substances and electron transporting substances can be used in combination. As these compounds, succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, Trimellitic anhydride,
Compounds such as phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid, trinitrofluorenone, quinone, benzoquinone, diphenoquinone, naphthoquinone, anthraquinone, and stilbenequinone. it can.

The protective layer 4 can be provided as needed for the purpose of improving printing durability and the like, and is made of a layer mainly composed of a resin binder or an inorganic thin film such as amorphous carbon. In the resin binder, for the purpose of improving conductivity, reducing the coefficient of friction, imparting lubricity, etc.
Metal oxides such as silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina) and zirconium oxide; metal sulfides such as barium sulfate and calcium sulfate; metal nitrides such as silicon nitride and aluminum nitride , A metal oxide fine particle, a fluorine resin particle such as a tetrafluoroethylene resin, a fluorine comb type graft polymer resin, or the like.

For the purpose of imparting charge transport properties, the photosensitive layer contains a charge transporting substance, an electron accepting substance, an electron transporting substance, or a compound of the present invention, or improves the leveling property of a film formed. And for the purpose of imparting lubricity
A leveling agent such as silicone oil or fluorine-based oil may be contained.

[0080]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Synthesis Example 1 Compound represented by the following general formula (VII-1) (Ciba Specialty Chemicals Co., Ltd .: TINUVIN57)
1) 19.7 g (50 mmol) of the following general formula (VII-
8.9 g (50) of the compound represented by 2) 2-tert-butyl-4,6-dimethylphenol (Tokyo Chemical Industry Co., Ltd.)
mmol) were dissolved in 500 ml of chloroform. To this, 23.7 g of potassium permanganate (150
mmol) and heated to reflux at about 57 ° C. for 8 hours.
After standing at room temperature, the mixture was filtered, and the solvent was removed from the obtained filtrate to obtain a solid. This was recrystallized with a mixed solvent of ethanol and toluene to obtain 12.4 g (22 mmol) of the compound of the formula (I-1-32) in a yield of 44%.

Synthesis Example 2 Compound represented by the following general formula (VII-3) (Ciba Specialty Chemicals Co., Ltd .: TINUVIN32)
6) 15.8 g (50 mmol) of the following general formula (VII-
11.0 g of the compound 3,5-di-tert-4-hydroxytoluene (Tokyo Kasei Kogyo Co., Ltd.) represented by 4) (50 m
mol) were dissolved in 500 ml of chloroform.
23.7 g of potassium permanganate (150 mm
ol) and heated to reflux at about 57 ° C. for 6 hours. After standing at room temperature, filtration, the solvent was removed from the obtained filtrate,
A solid was obtained. This was recrystallized with a mixed solvent of ethanol and toluene to obtain 15.4 g (29 mmol) of the compound of the formula (I-1-58) in a yield of 58%.

Synthesis Example 3 A compound represented by the following formula (VII-1) (Ciba Specialty Chemicals Co., Ltd .: TINUVIN57)
1) 39.4 g (100 mmol) was dissolved in 500 ml of chloroform. To this, 23.7 g (150 mmol) of potassium permanganate was added, and at about 57 ° C., 8
Heated to reflux for an hour. After standing at room temperature, the mixture was filtered, and the solvent was removed from the obtained filtrate to obtain a solid. This was recrystallized with a mixed solvent of ethanol and toluene to obtain 12.5 g (16 mmol) of the compound of the formula (I-2-5) at a yield of 32%.

Synthesis Example 4 A compound represented by the following general formula (VII-3) (Ciba Specialty Chemicals Co., Ltd .: TINUVIN32)
6) 31.6 g (100 mmol) was dissolved in 500 ml of chloroform. To this, 23.7 g (150 mmol) of potassium permanganate was added.
Heated to reflux for an hour. After standing at room temperature, the mixture was filtered, and the solvent was removed from the obtained filtrate to obtain a solid. This was recrystallized with a mixed solvent of ethanol and toluene, and 12.6 g (20 mmol) of the compound of the formula (I-2-12) was obtained.
A yield of 40% was obtained.

Synthesis Example 5 38.8 g (100 m) of a compound represented by the following formula (VII-5) (Kyodo Yakuhin Co., Ltd .: Biosorb 590)
mol) was dissolved in 500 ml of chloroform. To this, 23.7 g of potassium permanganate (150 mmo
l) was added, and the mixture was heated under reflux at about 57 ° C. for 10 hours. After standing at room temperature, filtration, the solvent was removed from the obtained filtrate,
A solid was obtained. This was recrystallized with a mixed solvent of ethanol and toluene to obtain 6.5 g (8 mmol) of the compound of the formula (I-2-9) in a yield of 17%.

Photoreceptor Example 1 A plate-like photoreceptor was prepared for evaluation of electrical characteristics, and a drum-like photoreceptor (30 mmφ) was used for print evaluation. An undercoat layer solution having the following composition was dip-coated on the aluminum plate and the aluminum tube, respectively, and dried at 100 ° C. for 60 minutes to form an undercoat layer having a thickness of 0.3 μm. Hereinafter, "parts" indicates parts by weight. Soluble nylon (Amilan CM8000: manufactured by Toray Industries, Inc.) 3 parts Methanol / methylene chloride mixed solvent (5/5) 97 parts

Next, a single-layer type photosensitive layer dispersion having the following composition was applied by dip coating and dried at 100 ° C. for 60 minutes to form a single-layer type photosensitive layer having a thickness of 25 μm. Charge generating substance: X-type metal-free phthalocyanine 0.2 part Hole transporting substance: Compound of the above formula (IV-101) 6 parts Electron transporting substance: Compound of the above formula (I-1-32) [Synthesis Example 1] 3 parts Antioxidant: 3,5-di-tert-4-hydroxytoluene (BHT) (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part Silicone oil: KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.01 Part Binder resin: bisphenol Z-type polycarbonate resin [Resin having the above formula (VI-3) as a structural unit] (Panlite TS2020: manufactured by Teijin Chemicals Ltd.) 11 parts Methylene chloride 100 parts Electrophotography as described above The body was made.

Photoconductor Example 2 In the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transport material of the above formula (I-1-32) was replaced with the above formula (I-32).
A photoconductor was prepared by the same way as that of Photoconductor Example 1 except that 3 parts of 1-58) was replaced with the electron transport material.

Photoconductor Example 3 Of the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transport material of the above formula (I-1-32) was replaced with the above formula (I-32).
A photoreceptor was prepared in the same manner as in Example 1, except that 3 parts of the electron transporting material of 2-5) was used.

Photoconductor Example 4 Of the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transport material of the above formula (I-1-32) was replaced with the above formula (I-32).
A photoconductor was prepared in the same manner as photoconductor example 1, except that 3 parts of electron transport material in 2-12) was used.

Photoreceptor Example 5 In the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transport material of the above formula (I-1-32) was replaced by the above formula (I-32).
A photoconductor was prepared in the same manner as photoconductor example 1, except that 3 parts of electron transport material in 2-9) was used.

Photoconductor Example 6 In the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transporting material of the above formula (I-1-32) was replaced with the above formula (I-32).
2-5), in place of 3 parts of the electron transport material, the above formula (IV-10)
A photoconductor was prepared in the same manner as in Photoconductor Example 1, except that 6 parts of the hole transport material of 1) was replaced with 6 parts of the hole transport material of the above formula (IV-66).

Photoreceptor Example 7 In the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transport material of the above formula (I-1-32) was replaced with the above formula (I-32).
2-5), in place of 3 parts of the electron transport material, the above formula (IV-10)
6 parts of the hole transport material of the formula (IV-5) and 3 parts of the hole transport material of the formula (IV-23)
A photoconductor was prepared in the same manner as in Photoconductor Example 1 except that the parts were replaced.

Photoconductor Example 8 Of the composition of the photosensitive layer dispersion used in Example 1, 3 parts of the electron transporting material of the above formula (I-1-32) was replaced with the above formula (I-32).
2-5), in place of 3 parts of the electron transport material, the above formula (IV-10)
A photoconductor was prepared in the same manner as in Photoconductor Example 1, except that 6 parts of the hole transport material of 1) was replaced with 6 parts of the hole transport material of the above formula (V-15).

Photoconductor Comparative Example 1 Among the compositions of the photosensitive layer dispersion used in Photoconductor Example 1,
3 parts of the electron transport material of the formula (I-1-32) is represented by the following formula (VIII-1): A photoreceptor was prepared in the same manner as in Photoreceptor Example 1, except that 3 parts of a stilbenequinone compound (manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

Photoconductor Comparative Example 2 Among the compositions of the photosensitive layer dispersions used in Photoconductor Example 1,
3 parts of the electron transport material of the formula (I-1-32) is represented by the following formula (VIII-2): A photoreceptor was prepared in the same manner as in Photoreceptor Example 1, except that 3 parts of the diphenoquinone compound represented by were used.

Photoconductor Comparative Example 3 Of the composition of the photosensitive layer dispersion used in Example 1 of the photoconductor,
A photoreceptor was prepared in the same manner as in Photoreceptor Example 1, except that the electron transport material of the formula (I-1-32) was not contained.

Photoreceptor Example 9 A plate-shaped photoreceptor was prepared for evaluating electrical characteristics, and a drum-shaped photoreceptor (30 mmφ) was used for printing evaluation. An undercoat layer dispersion having the following composition was dip-coated on an aluminum plate and an aluminum tube, respectively, and dried at 100 ° C. for 30 minutes to form a 3 μm-thick undercoat layer. Soluble nylon (Amilan CM8000: manufactured by Toray Industries, Inc.) 5 parts Aminosilane-treated titanium oxide fine particles 5 parts Methanol / methylene chloride mixed solvent (6/4) 90 parts

Next, a charge generation layer dispersion having the following composition was dip-coated and dried at 100 ° C. for 30 minutes to form a 0.3 μm-thick charge generation layer. Titanyl phthalocyanine (crystal form described in JP-A-8-20923) 1 part Vinyl chloride copolymer resin (MR-110: manufactured by Zeon Corporation) 1 part Methylene chloride 98 parts

Next, a charge transport layer solution having the following composition was applied by dip coating and dried at 100 ° C. for 30 minutes to form a charge transport layer having a thickness of 28 μm. Hole transport material: 8 parts of the compound of the formula (IV-101) Electron transport material: compound of the formula (I-2-5) [Synthesis Example 3] 1 part Antioxidant: 3,5-di-tert 4-Hydroxytoluene (BHT) (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part Silicone oil: KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.01 part Binder resin: polycarbonate resin [Formula (IV-1) ) And (IV-2) Compound Resin] (BPPC average molecular weight 20,000: manufactured by Idemitsu Kosan Co., Ltd.) 11 parts Solvent: methylene chloride 90 parts The electrophotographic photoreceptor was prepared as described above.

Photoconductor Example 10 In the composition of the charge transport layer solution of Photoconductor Example 9, 1 part of the electron transport material of the above formula (I-2-5) was replaced by the above formula (I-2)
A photoconductor was prepared by the same way as that of Photoconductor Example 9 except that 1 part of the electron transport material in -9) was changed.

Photoconductor Example 11 In the composition of the charge transport layer solution of Photoconductor Example 9, 8 parts of the hole transport material of the above formula (IV-101) was replaced by the above formula (V-2)
A photoconductor was prepared by the same way as that of Photoconductor Example 9 except that 7 parts of hole transport material of 9) and 1 part of hole transport material of formula (V-38) were used.

Photoconductor Comparative Example 4 In the composition of the charge transport layer solution of Photoconductor Example 9, one part of the electron transport material of the above formula (I-2-5) was replaced with the above formula (VIII-
A photoconductor was prepared by the same way as that of Photoconductor Example 9 except that 1 part of diphenoquinone compound in 2) was used.

Photoreceptor Comparative Example 5 The same procedure as in Photoreceptor Example 9 was carried out, except that the composition of the charge transport layer solution of Photoreceptor Example 9 was not made to contain the electron transport material of the above formula (I-2-5). A photoreceptor was produced.

Photoconductor Example 12 An undercoat layer solution having the following composition was dip-coated on an aluminum plate and an aluminum tube, respectively, and dried at 100 ° C. for 30 minutes to form a 3 μm-thick undercoat layer. . Soluble nylon (Amilan CM8000: manufactured by Toray Industries, Inc.) 5 parts Electron transporting substance: Compound of formula (I-2-9) [Synthesis Example 5] 2 parts Methanol / methylene chloride mixed solvent (6/4) 90 parts

Next, a charge generation layer dispersion having the following composition was applied by dip coating and dried at 100 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.3 μm. Y-type titanyl phthalocyanine 1 part Polyvinyl butyral resin (BH-3: manufactured by Sekisui Chemical Co., Ltd.) 1 part Methylene chloride 98 parts

Next, a charge transport layer solution having the following composition was applied by dip coating and dried at 100 ° C. for 30 minutes to form a charge transport layer having a thickness of 28 μm. Charge transport substance: 9 parts of the compound of the formula (IV-66) Antioxidant: 3,5-di-tert-4-hydroxytoluene (BHT) (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part Binder resin: polycarbonate resin [Copolymer resin of compounds of formulas (IV-1) and (IV-2)] (BPPC average molecular weight: 20,000, manufactured by Idemitsu Kosan Co., Ltd.) 11 parts Solvent: methylene chloride 90 parts As described above, the electrophotographic photoreceptor Was prepared.

Photoconductor Comparative Example 6 In the composition of the undercoat layer solution of Photoconductor Example 12, 2 parts of the electron transport material of the above formula (I-2-9) was replaced with the above formula (VIII-
A photoconductor was prepared by the same way as that of Photoconductor Example 12 except that 2 parts of diphenoquinone compound in 2) was used.

Photoreceptor Comparative Example 7 Photoreceptor Example 12 was the same as Photoreceptor Example 12 except that the composition of the undercoat layer solution did not contain the electron transport material of the above formula (I-2-9). A photoreceptor was produced.

Photoconductor Examples 1 to 8 and Photoconductor Comparative Examples 1 to 3
The evaluation of electrical characteristics was performed using a plate-shaped photoreceptor using an electrostatic copying paper tester EPA-8100 manufactured by Kawaguchi Electric Works, Ltd. Under an environment of a temperature of 23 ° C. and a humidity of 50%, the surface was charged in a dark place so that the surface potential was about +600 V, and the retention rate of the surface potential for 5 seconds before exposure was determined by the following equation. Retention Vk5 (%) = V5 / V0 × 100 V0: Surface potential immediately after charging V5: Surface potential after 5 seconds (at the start of exposure)

Next, monochromatic light of 1.0 μW / cm ² , which is obtained by dividing the light of a halogen lamp into 780 nm light with a filter, is exposed for 5 seconds, and the exposure amount required to reduce the surface potential to half (+300 V) is determined by the sensitivity E. calculated as _{1/2 (μJ} / cm ^2), it was determined and the surface potential of 5 seconds after exposure as residual potential Vr (V).

As an evaluation of the durability by actual printing, a drum-shaped photoreceptor was manufactured using a laser printer HL-
730, temperature of 22 ° C, humidity of 48%,
Print black solid image, white solid image, halftone image,
With Macbeth densitometer (Macbeth RD914)
The image density was measured and the initial image was evaluated. Subsequently, an image having a printing rate of about 5% was printed on 5,000 sheets, and after 5,000 sheets, a black solid image, a white solid image, and a halftone image were printed again, and the image after printing 5,000 sheets was evaluated. . The evaluation results are shown in Table 1 below.

[0112]

[Table 1] The values in parentheses in the image evaluation in the table are the image density measured values by the Macbeth densitometer. Poor: Precipitation due to poor compatibility between the stilbenequinone-based compound and the binder resin. occured. Poor: Fine black spots called fog were generated on the entire white solid image. Poor: The halftone image was crushed, giving a black solid image.

Photoconductor Examples 9 to 12, Photoconductor Comparative Examples 4 to
Evaluation of 7 Evaluation of electrical characteristics was performed using a plate-shaped photoreceptor using the same test apparatus EPA-8100 as described above. Temperature 23
Surface potential of about -6 in a dark place under an environment of 50 ° C and 50% humidity
It was charged so as to have a voltage of 00 V, and then the retention rate of the surface potential for 5 seconds until the exposure was determined by the following equation. Retention Vk5 (%) = V5 / V0 × 100 V0: Surface potential immediately after charging V5: Surface potential after 5 seconds (at the start of exposure)

Next, monochromatic light of 1.0 μW / cm ² obtained by separating the light of a halogen lamp to 780 nm with a filter is exposed for 5 seconds, and the exposure amount required for the surface potential to become −100 V is determined by the sensitivity E ₁₀₀ ( μJ / cm ² ), and the surface potential 5 seconds after exposure was determined as a residual potential Vr (V).

As an evaluation of durability by actual printing, a drum-shaped photoreceptor was attached to a laser printer Laser Jet 4 plus manufactured by Hewlett-Packard Company, and a black solid image was obtained under an environment of a temperature of 23 ° C. and a humidity of 49%.
A solid white image and a halftone image were printed, the image density was measured with a Macbeth densitometer (Macbeth RD914), and the initial image was evaluated. Subsequently, an image with a printing rate of about 5% was printed on 10,000 sheets, and after 10,000 sheets, a black solid image, a white solid image, and a halftone image were printed again. Similarly, evaluation of the image after printing 10,000 sheets was performed. Was done. The results of these evaluations are shown in Table 2 below.

[0116]

[Table 2] Numerical values in parentheses for image evaluation in the table are image density measured values by a Macbeth densitometer. Poor: Small black spots called fog were generated on the entire white solid image. Poor: The halftone image was crushed, giving a black solid image. Poor: The density of the black solid image was lowered, and no solid black image was obtained. Poor: The halftone image was blurred and the image was uneven.

As can be seen from the results of Tables 1 and 2, when the stilbenequinone compound of Comparative Example is contained in a large amount, the stilbenequinone compound precipitates due to poor compatibility with the binder resin and causes image defects.

On the other hand, the novel stilbenequinone compound of the present invention has high compatibility and, when incorporated in the photosensitive layer or the undercoat layer, has a lower sensitivity and residual potential than the diphenoquinone compound of the comparative example. It has excellent electrical properties and good repetition stability. In particular, when incorporated in a single-layer type photosensitive layer, the effect of improving sensitivity is high.

[0119]

As described above, according to the present invention, a novel stilbenequinone compound having an excellent electron transporting property can be obtained. By using this compound in an electrophotographic photoreceptor, the electrical properties and the repetition stability can be improved. An electrophotographic photosensitive member having excellent and high durability can be obtained, and is useful for an electrophotographic apparatus such as a printer, a copying machine, and a facsimile using an electrophotographic method.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an electrophotographic photosensitive member according to the present invention.

FIG. 2 is a schematic sectional view of a single-layer type electrophotographic photoconductor according to the present invention.

FIG. 3 is a schematic sectional view of a laminated electrophotographic photosensitive member according to the present invention.

FIG. 4 is a schematic sectional view of another laminated electrophotographic photosensitive member according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive substrate 2 undercoat layer 3 photosensitive layer 3 a charge generation layer 3 b charge transport layer 4 protective layer

Claims (6)

[Claims] 1. A compound represented by the following general formula (I): (Wherein at least one of R ^{1 to} R ⁴ is a group represented by the following general formula (II): (Wherein, R ^{9 to} R ¹² each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms), and the remaining R ^{1 to} R ⁴ and R ⁵ ~ R
⁸ independently has a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a halogenated alkyl group, a cyclic alkyl group which may have a substituent, and a substituent. An aryl group which may be substituted, a heterocyclic group which may have a substituent, an aralkyl group which may have a substituent,
To 6, an alkoxy group, a halogenated alkoxy group, or the following general formula (III): Or two groups may combine to form a cyclic alkyl group which may have a substituent or an aromatic ring which may have a substituent) A novel stilbenequinone compound characterized by the above-mentioned. 2. An electrophotographic photosensitive member having a photosensitive layer provided on a conductive substrate, wherein the photosensitive layer contains the novel stilbenequinone compound according to claim 1. body. 3. The electrophotographic photoconductor according to claim 2, wherein the photosensitive layer is a single-layer type photosensitive layer. 4. An electrophotographic photoreceptor in which an undercoat layer and a photosensitive layer are sequentially provided on a conductive substrate, wherein the undercoat layer contains the novel stilbenequinone compound according to claim 1. A photoconductor for electrophotography, characterized by: 5. The photosensitive layer according to claim 1, wherein the hole transport material has the following general formula (IV): (Wherein, R ^{13 to} R ⁴⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms).
The electrophotographic photosensitive member according to any one of the above. 6. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 2. Description: