JP2658241B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member having a photosensitive layer containing a specific azo material.

2. Description of the Related Art Conventionally, inorganic photoconductive materials such as amorphous selenium, selenium alloy, cadmium sulfide, and zinc oxide, and organic photoconductive materials represented by polyvinyl carbazole and its derivatives are widely used as electrophotographic photoreceptors. Are known.

The organic photoconductive substance has an advantage that it is excellent in transparency, film forming property, flexibility, manufacturability and the like as compared with the inorganic photoconductive substance.

Further, in recent years, electrophotographic photoreceptors in which various azo pigments are contained in a photosensitive layer have been proposed. (For example, Japanese Patent Publication No. 60-
No. 29109, JP-A-61-129653, JP-A-58-194035,
Problems to be Solved by the Invention However, conventionally proposed electrophotographic photoreceptors using azo pigments have insufficient light sensitivity in a long wavelength region. In addition, it is not sufficient in terms of chargeability and durability, and cannot be used satisfactorily in a printer using a semiconductor laser as a light source.

Accordingly, it is an object of the present invention to provide an electrophotographic photosensitive member having high sensitivity and high durability. Another object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity to a wide range of light sources such as a semiconductor laser.

Means and Actions for Solving the Problems The electrophotographic photoreceptor of the present invention is characterized by having a photosensitive layer containing a bisazo compound represented by the following general formula (I) on a conductive substrate.

(Wherein X is an oxygen atom or R ₁ represents a hydrogen atom, a halogen atom or a nitro group, R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, a nitro group, a cyano group or a trifluoromethyl group And A represent a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring.) Hereinafter, the present invention will be described in detail.

The bisazo compound represented by the general formula (I) used in the electrophotographic photoreceptor of the present invention will be described in more detail. X is an oxygen atom or Is shown.

R ₁ represents a hydrogen atom, a halogen atom or a nitro group, and is preferably a hydrogen atom or a chlorine atom in consideration of sensitivity and durability.

R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, a nitro group, a cyano group or a trifluoromethyl group, but when sensitivity and durability are considered, a hydrogen atom or a chlorine atom is preferable.

A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring. Examples of the divalent aromatic hydrocarbon group include divalent monovalent groups such as o-phenylene. Divalent fused polycyclic aromatic carbon such as cyclic aromatic hydrocarbon group, o-naphthylene group, perinaphthylene group, 1,2-anthraquinonylene group, 9,10-phenanthrylene group and 2,3-fluorenylene group And a hydrogen group.

Examples of the divalent heterocyclic group containing a nitrogen atom in the ring include a 3,4-pyrazoldiyl group, a 2,3-pyridinediyl group, a 3,4-pyridinediyl group, a 4,5-pyrimidinediyl group, Examples thereof include divalent heterocyclic groups such as a 5,6-benzimidazolediyl group and a 6,7-quinolinediyl group.

The above divalent aromatic hydrocarbon group or the divalent heterocyclic group containing a nitrogen atom in the ring may have a substituent.
Examples of the substituent include a C _{1 to} C ₁₈ alkyl group, a C _{1 to} C ₄ alkoxy group, a C _{1 to} C ₄ alkoxycarbonyl group, a carboxyl group, a hydroxy group, a nitro group, a cyano group, a halogen atom, Examples include a fluoromethyl group, a carbamoyl group, a sulfamoyl group, and a phenoxy group.

In consideration of sensitivity and durability, A is an o-phenylene group, an o-naphthylene group, a perinaphthylene group,
3-pyridinediyl group, 3,4-pyridinediyl group, 4,5-
Pyrimidinediyl group, 9,10-phenanthrylene group or 2,
A 3-fluorenylene group is preferable, and as a substituent, an alkyl group, an alkoxy group, a carboxyl group, a hydroxy group, a nitro group, a halogen atom, and a trifluoromethyl group are preferable.

Specific examples of the bisazo compound used in the present invention include the following. However, the bisazo compound in the present invention is not limited to these.

The bisazo compound used in the present invention is, for example, the corresponding diamine tetrazotized by a conventional method, the general formula Or in the presence of a base, or after isolating the corresponding tetrazonium salt of a diamine in the form of a borofluoride salt or a zinc chloride double salt, a suitable solvent (eg, N, N -Dimethylformamide, dimethylsulfoxide and the like) in the presence of a base and coupling with the above coupler.

In the present invention, the bisazo compound is contained in a photosensitive layer provided on a conductive support. The photosensitive layer may have a single-layer structure, or may have a functional separation into a charge generation layer and a charge transport layer. It may have a structure.

The electrophotographic photoreceptor of the present invention comprises, for example, (1) an electroconductive support provided with a photosensitive layer obtained by dispersing a bisazo compound in a binder resin containing a charge transporting substance; A photosensitive layer in which a bisazo compound and a charge transfer complex are dispersed in a binder resin on a support; (3) a charge generating layer containing a bisazo compound and a charge transport material on a conductive support; It can be roughly classified into those provided with a charge transport layer.

As the conductive support in the electrophotographic photoreceptor of the present invention, a metal plate, a metal drum, or a metal foil made of aluminum, nickel, chromium, stainless steel or the like, and a plastic film provided with a thin film of a metal or other conductive substance For example, paper or a plastic film coated or impregnated with a conductivity-imparting agent is used.

In the present invention, when the bisazo compound is dispersed in the binder resin in the photosensitive layer formed on the conductive support, the bisazo compound is 3 μm or less, preferably 0.1 μm or less.
It is desirable that the particles are dispersed as fine particles having a particle diameter of 3 μm or less, and the compounding amount thereof is 20% by weight to 90% by weight based on the photosensitive layer.

As the binder resin for dispersing the bisazo pigment, polystyrene, silicone resin, polycarbonate, acrylic resin, methacrylic resin, polyester, vinyl polymer, for example, polyvinyl butyral, etc., celluloses, for example, cellulose ester, cellulose ether, alkyd, etc. Resin or the like can be used.

Examples of the charge transport material used in the present invention include the following.

Since these compounds have no film-forming property by themselves, they are used in combination with a resin having a good film-forming property when forming a charge transport layer. Examples of the resin that can be used include polycarbonate, polyacrylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylate, and styrene-methacrylate copolymer.

In the electrophotographic photoreceptor of the present invention, when the photosensitive layer has a function-separated type laminated structure, a charge transport layer may be provided on the charge generation layer, or the charge generation layer may be provided on the charge transport layer. May be provided. The thickness of the charge generation layer is 0.
The thickness of the charge transport layer is set to about 5 to 50 μm. In the electrophotographic photoreceptor of the present invention, it is preferable to provide a charge injection blocking layer between the photosensitive layer and the conductive substrate.

Examples Next, the present invention will be described with reference to Examples and Comparative Examples.

Example 1 1 part by weight of a polyvinyl butyral resin (trade name: BLX, manufactured by Sekisui Chemical Co., Ltd.) is dissolved in 40 parts by weight of cyclohexane, 4 parts by weight of Exemplified Compound No. 1 is mixed therein, and then a paint shaker The resulting dispersion was applied on an aluminum sheet by an applicator and dried to form a charge generation layer. The film thickness after drying is
0.2 μm.

N, N'-diphenyl-N, N 'is formed on the formed charge generation layer.
-Bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine 1 part by weight, 1 part by weight of polycarbonate resin (manufactured by Panlite (registered trademark) Teijin Limited),
A uniform solution consisting of 10 parts by weight of tetrahydrofuran was applied by a bar coater and dried to form a charge transport layer. The film thickness after drying was 15 μm.

The characteristics of the electrophotographic photoreceptor thus prepared were evaluated as follows using an electrostatic copying paper test apparatus (SP-428, manufactured by Kawaguchi Electric Works, Ltd.). First, after negatively charging by applying a -6 KV corona discharge, leave it in a dark place for 2 seconds,
The surface potential Vpo (volt) at that time was measured, and then light was irradiated using a tungsten lamp so that the illuminance of the surface became 5 lux, and the time until the surface potential became 1/2 of Vpo was determined. The exposure amount E 1/2 (lux · sec) was calculated.

Further, the same measurement was repeated 20 times. The result is first
It is as shown in the table.

Examples 2 to 8 In Example 1, instead of Exemplified Compound No. 1, Exemplified Compound Nos. 2, 19, 20, 24, 35, 59 and 61 (Examples 2 to 8 respectively)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except for using, and evaluated in the same manner. The results are as shown in Table 2.

Examples 9 to 16 The following measurements were performed to clarify that the composition had excellent sensitivity to light having a long wavelength. Using the electrophotographic photoreceptors of Examples 2 to 8 (Examples 9 to 16 respectively), after charging by corona discharge in a dark place, monochromatic light of 1 μW / cm ² dispersed at 780 nm using a monochromator was used. The photoreceptor was irradiated. Then, the time until the surface potential became 1/2 was measured, and the exposure amount was obtained. The results are as shown in Table 3.

Comparative Examples 1 to 3 In Example 1, except that the compound represented by the following structural formula (1), (2), or (3) (Comparative Examples 1 to 3) was used instead of Exemplified Compound No. 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1, and its characteristics were evaluated in the same manner. The results are as shown in Table 4.

Comparative Examples 4 to 6 Using the electrophotographic photosensitive members of Comparative Examples 1 to 3 (Comparative Examples 4 to 6, respectively), evaluation was performed in the same manner as in Example 9. The results are as shown in Table 5.

Effects of the Invention Since the electrophotographic photoreceptor of the present invention contains the above bisazo compound in the photosensitive layer, it has good chargeability and high photosensitivity in a long wavelength region. Therefore, the electrophotographic photoreceptor of the present invention can be applied to various printers, microfilm readers, electrophotographic plate making systems and the like that use a wide range of light sources such as semiconductor lasers.

Continued on the front page (72) Inventor Akira Imai 1600 Takematsu, Fuji Xerox Co., Ltd., Takematsu Office, Minami Ashigara City, Kanagawa Prefecture ) Inventor: Fumiaki Taho 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. Takematsu Office (56) References JP-A-61-23155 (JP, A) JP-A-63-89570 (JP, A) JP-A-63-36258 (JP, A) JP-A-62-139564 (JP, A) JP-A-63-38945 (JP, A) JP-A-63-113466 (JP, A)

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a bisazo compound represented by the following general formula (I) on a conductive substrate. (Wherein X is an oxygen atom or R ₁ represents a hydrogen atom, a halogen atom or a nitro group, R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, a nitro group, a cyano group or a trifluoromethyl group , A represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring)