JPH06102684A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body excellent in image quality, stability and durability. CONSTITUTION:When a photosensitive layer contg. at least a positive hole transferring agent is formed on an electric conductive substrate to obtain an electrophotographic sensitive body, an amine compd. represented by the formula and a dicyanovinyl compd. are incorporated into the photosensitive layer. In the formula, each of R1-R4 is H, alkyl or aryl, Z is a group of atoms required to form an N-contg. alicyclic structure, X is H or a monovalent org. residue and Y is an org. residue.

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 particularly to an electrophotographic photosensitive member excellent in image quality, stability and durability.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is usually formed by providing a photosensitive layer on a conductive substrate. For the photosensitive layer, an inorganic photoconductive material such as silicon, selenium, CdS, or zinc oxide or an organic photoconductive material is used. However, inorganic photoconductive materials have problems such as toxicity, difficulty in waste disposal, and high cost. With recent environmental problems and increasing demand for miniaturization, organic electrophotographic photoreceptors using organic photoconductive materials (hereinafter, OPC) is becoming the mainstream. OPCs with excellent sensitivity characteristics for long-wavelength light including near-infrared light have also been developed due to the progress of dye molecular design and pigment design, and they have been developed into optical printers and digital copying machines using semiconductor lasers and LEDs as light sources. It is being actively researched for use.

The structure of the OPC includes a function-separated laminated type in which a charge generation layer having a function of absorbing light and generating an electric charge and a charge transport layer having a function of transporting the electric charge are separated and laminated, and respective functions. It can be roughly classified into a single layer type that has both. In either method, it is necessary to efficiently transport the charges generated during the charging exposure and to neutralize the charges on the surface of the photoconductor. Furthermore, these functions must be stably exerted.

However, the OPC currently used
When it is repeatedly used in an electrophotographic apparatus, changes such as a decrease in charging potential, an increase in residual potential, a change in sensitivity characteristics, a decrease in resolution, etc. occur, making it unusable. Although not all of the causes of such changes have been clarified, one of the main causes is oxidative deterioration of a photoconductive material, particularly a hole transport material used as a charge transport material. In electrophotography, the photoreceptor is usually charged by corona discharge or contact with a conductive member to which a voltage is applied, and the surface of the photoreceptor is charged with an ionic gas generated in a high electric field and the surrounding environment. Oxidative deterioration is caused by adsorption of highly oxidizing gas generated by reacting with the gas. Especially, in corona discharge, such oxidative deterioration becomes more remarkable due to generation of ozone. On the other hand, in the process of charge generation and charge transport during exposure, there are causes of deterioration such as photooxidation and oxidation due to movement of charges. As a result of such oxidative deterioration, accumulation of charges in the photosensitive layer and reduction of surface resistance are caused, and the charging potential decreases, the residual potential increases, the resolution decreases, and the previous image appears as an afterimage overlapping on the image. It is a photoconductor that has a short life due to the occurrence of memory.

To address these problems, for example, Japanese Patent Laid-Open No. 57-12
2444, JP-A-62-105151 and JP-A-63-73.
JP-A No. 256-256 describes that a stabilizer such as an antioxidant is added to the photosensitive layer to prevent oxidative deterioration.

However, in such a conventional technique, OP
If an attempt is made to stabilize the characteristics of C, the electrophotographic characteristics such as an increase in residual potential and a decrease in sensitivity will be deteriorated, and printing quality will be deteriorated due to the generation of memory and a decrease in resolution, making it unusable for practical use. Under the present circumstances, no OPC satisfying both high image quality and stability is obtained yet. Therefore, an object of the present invention is to provide an organic electrophotographic photosensitive member that satisfies both high image quality and stability and can obtain good image quality for a long period of time.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies on prevention of oxidative deterioration of an electrophotographic photoreceptor having a photosensitive layer containing a hole-transporting agent, and as a result, a specific amine compound and dicyanovinyl compound By adding together with the layer containing the hole transporting agent, the electrophotographic photosensitive material has excellent electric characteristics, high resolution, no memory generation, and improved oxidation resistance, and these characteristics do not change even after repeated use over a long period of time. After finding that the body is obtained, the present invention has been completed. That is, the present invention is an electrophotographic photoreceptor comprising a photosensitive layer containing at least a hole transfer agent on a conductive substrate, wherein the amine compound represented by the following general formula (1) is contained in the layer containing the hole transfer agent. And a dicyanovinyl compound.

[0008]

[Chemical 2]

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or an alkyl group or an aryl group which may have a substituent, and Z represents a nitrogen-containing alicyclic structure. Represents an atomic group necessary for formation, X represents a hydrogen atom or a monovalent organic residue, and Y represents an organic residue.) In the above general formula (1), R ₁ , R ₂ , R ₃ As R ₄ and R ₄ , a hydrogen atom or an alkyl group having 3 or less carbon atoms is particularly preferable. The nitrogen-containing alicyclic structure formed by Z together with N is a 5- to 7-membered ring.
A ring having C as a main constituent atom and containing N 2 is preferable. Further, X is preferably a hydrogen atom or an alkyl group having 3 or less carbon atoms or an acyl group.

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

[0011]

[Chemical 3]

[0012]

[Chemical 4]

[0013]

[Chemical 5]

[0014]

[Chemical 6]

These amine compounds represented by the general formula (1) may be used as a mixture of two or more kinds. The content of these amine compounds in the layer containing the hole transfer agent is 0.1 to 20.
Weight percent is preferred. Further, in the present invention, the dicyanovinyl compound used together with the amine compound represented by the general formula (1) is an electron-accepting compound, and specific examples of this dicyanovinyl compound are shown below, but the present invention is It is not limited to these.

[0016]

[Chemical 7]

[0017]

[Chemical 8]

These dicyanovinyl compounds may be used as a mixture of two or more kinds. Particularly preferred dicyanovinyl compounds are B-1 and B-8. The content of these dicyanovinyl compounds in the layer containing the hole transfer agent is preferably 0.1 to 20% by weight.

The basic constitution of the electrophotographic photosensitive member provided by the present invention will be specifically described. A charge generating agent is dispersed in a layer containing a hole transfer agent and a bonding agent as main components on a conductive substrate. The single-layer type photoconductor, and the laminated type photoconductor in which a charge generation layer containing a charge generating agent as a main component and a charge transporting layer containing a hole transporting agent and a binder as main components are sequentially provided on a conductive substrate. As an example, there may be mentioned a laminated photoreceptor or the like in which a charge transporting layer containing a hole transporting agent and a binder as main components and a charge generating layer containing a charge generating agent as a main component are sequentially provided on a conductive substrate. it can. In addition, if necessary, an intermediate layer may be provided between the conductive substrate and the photosensitive layer, or a surface protective layer may be provided outside the photosensitive layer.

The conductive substrate is not particularly limited, and a generally known substrate can be used. For example, a plate-shaped, cylindrical, or foil-shaped substrate made of aluminum, stainless steel, copper, nickel, or the like, a substrate obtained by laminating or vapor-depositing these thin films, and a substrate made of paper, plastic, or glass that has been subjected to a conductive treatment are mentioned. be able to. Further, an aluminum substrate whose surface is anodized can also be preferably used.

The intermediate layer is not particularly limited, and a generally known material can be used. For example, a resin film of polyamide, polyester, polyurethane, polyvinyl butyral, or the like, or a dispersion film in which titanium oxide, tin oxide, glass powder, or the like is dispersed in these resin films can be used.

The surface protective layer is not particularly limited, and a generally known material can be used. For example polyamide,
A resin film which does not absorb a light source such as a thermosetting silicone resin, a crosslinked acrylic resin, or a silicone-urethane resin can be used.

The method for forming these intermediate layer, photosensitive layer or surface protective layer on the conductive substrate is not particularly limited, and examples thereof include dip coating method, spray coating method, bar coating method, roll coating method and calendar coating method. These methods can be used alone or in combination.

The charge generating agent used in the present invention is not particularly limited, but examples thereof include perylene pigments, polycyclic quinone pigments, phthalocyanine pigments, azo pigments, squarium salt pigments, quinacridone pigments and anthanthrone pigments. You can The charge generation layer used in the laminated type photoreceptor is obtained as a vapor deposition film of the above charge generation agent or a dispersion film in a binder. The binder is not particularly limited as long as it is a resin having excellent dispersibility of the pigment used, for example, polycarbonate, polyester, polyamide, polyacrylate, polymethacrylate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, Polyvinyl alcohol,
Polyacrylonitrile, polyacrylamide, acrylonitrile-butadiene copolymer, polysulfone, polyether sulfone, silicone resin, phenoxy resin, urethane resin or a mixture of two or more of these resins can be used. The film thickness is preferably 0.1 to 5 μm.

As the hole transfer agent used in the present invention, a generally known hole transfer agent can be used.
Examples thereof include a hydrazone compound, a stilbene compound, a butadiene compound, a triarylamine compound, a bistriaryl compound, a carbazole compound, a polyvinylcarbazole compound, an oxadiazole compound, an oxazole compound, a pyrazoline compound and a triphenylmethane compound. The charge transport layer binder is not particularly limited as long as it is an insulating resin and has excellent compatibility with the hole transport agent used.
For example, polycarbonate, polyarylate, polyester, polyamide, polyacrylate, polymethacrylate, polystyrene, styrene-acrylic copolymer, polyacrylonitrile, polyacrylamide, acrylonitrile-butadiene copolymer, polysulfone, polyether sulfone, silicone resin, phenoxy resin, Urethane resin, thermosetting epoxy resin or these resins 2
A mixture of two or more species can be used. The ratio of the hole transport material to the binder in the charge transport layer is 10:90 by weight.
90:10 is preferable, and 30:70 to 70:30 is particularly preferable. The thickness of the charge transport layer is preferably 10 to 40 μm. In the case of a single-layer type photoreceptor, it is obtained by dispersing the above charge generating agent in a photosensitive layer comprising the above hole transporting agent and the binder for the charge transporting layer. The ratio of the charge generating agent is 1 with respect to the photosensitive layer. It is preferably from 50 to 50% by weight, particularly preferably from 5 to 25% by weight, and the thickness of the photosensitive layer is preferably from 10 to 40 μm.

[0026]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The parts in the examples are based on weight.

Example 1 25 parts of an alcohol-soluble polyamide (Amilan CM-8000, manufactured by Toray Industries, Inc.) was added to 400 parts of methanol and n-butanol.
The intermediate layer coating material obtained by dissolving in 100 parts of the mixed solvent was applied to an aluminum cylinder by a dip coating method and dried to obtain an intermediate layer having a film thickness of 1 μm. Next, 5 parts of X-type metal-free phthalocyanine, polyvinyl butyral (S-REC BM-
2, Sekisui Chemical Co., Ltd.) 5 parts, cyclohexanone 400
Part, 1mmφ glass beads 650 parts are put in a sand mill, and 2
After time dispersion, a charge generation layer coating material was prepared. This paint is applied on the above intermediate layer by dip coating and dried to obtain a film thickness.
A 0.3 μm charge generation layer was obtained. Next, 40 parts of a butadiene compound represented by the following formula (CTM-1), 2 parts of an amine compound represented by the formula (A-4), 2 parts of a dicyanovinyl compound represented by the formula (B-9), polycarbonate-Z ( Z-500,
40 parts of Teijin Kasei Co., Ltd. was dissolved in 420 parts of 1,2-dichloroethane to obtain a charge transport layer coating material. This paint is applied on the charge generation layer by dip coating and dried to a film thickness of 20 μm.
To obtain a charge transport layer.

[0028]

[Chemical 9]

The drum-shaped electrophotographic photosensitive member produced as described above was mounted on a commercially available reversal development type laser beam printer, and surface potential measurement and printing test were conducted. As a result, the exposed area potential is -80V and the unexposed area potential is -600V.
Met. On the other hand, the print density (ID) of the solid black area is 1.40 (measured with a Macbeth densitometer), and the background (BG) is 0.
It was 30 (color difference meter 1001DP, made by Nippon Denshoku Industries), and no memory occurred. When the same evaluation is performed after 5000 sheets are continuously printed, the exposed portion potential is -75 V and the unexposed portion potential is -590 V.
V and ID were 1.41 and BG was 0.36, and no memory was generated.

Examples 2 to 5 Electrophotographic photoreceptors were prepared and evaluated in the same manner as in Example 1 except that the compounds shown in Table 1 were used as the amine compounds represented by the general formula (1). The results are shown in Table 1.

[0031]

[Table 1]

Examples 6 to 9 Electrophotographic photosensitive members were prepared in the same manner as in Example 1 except that the compound represented by the formula (A-8) was used as the amine compound and the compounds shown in Table 2 were used as the dicyanovinyl compound. It was prepared and evaluated. The results are shown in Table 2.

[0033]

[Table 2]

Comparative Example 1 An electron was prepared in the same manner as in Example 1 except that the amine compound represented by the formula (A-4) and the dicyanovinyl compound represented by the formula (B-9) were not added. A photographic photoreceptor was prepared and evaluated. As a result, the exposed area potential is -70.
V, the unexposed portion potential was -600 V. On the other hand, the print density (ID) of solid black areas is 1.45 and the background (BG) is 0.
3, there was no occurrence of memory. When the same evaluation was performed after 5000 sheets were continuously printed, the exposed portion potential was −115 V, the unexposed portion potential was −510 V, the ID was 1.15, and the BG was 1.25, and generation of memory was observed.

Comparative Example 2 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the dicyanovinyl compound represented by the formula (B-9) was not added. As a result, the exposed portion potential was -105 V and the unexposed portion potential was -600 V.
On the other hand, the print density (ID) of the solid black portion was 1.22 and the background (BG) was 0.3, and memory generation was observed.
When the same evaluation is performed after 5000 sheets are continuously printed, the exposed area potential is −120 V, the unexposed area potential is −560 V, ID is 1.10, and BG is
It was 0.80, and the occurrence of memory was observed.

Example 10 40 parts of a stilbene compound represented by the following formula (CTM-2), 1.5 parts of an amine compound represented by the formula (A-8), and formula (B-
1 part of dicyanovinyl compound (1.5 parts), polycarbonate-Z (Z-500, manufactured by Teijin Chemicals Ltd.) 40 parts
It was dissolved in 420 parts of 1,2-dichloroethane to obtain a charge transport layer coating material. This coating material was applied onto the charge generation layer prepared in the same manner as in Example 1 by a dip coating method and dried to obtain a charge transport layer having a thickness of 20 μm.

[0037]

[Chemical 10]

The drum-shaped electrophotographic photosensitive member produced as described above was evaluated in the same manner as in Example 1. As a result, the exposed portion potential was -70 V and the unexposed portion potential was -600 V. On the other hand, the print density (ID) of the solid black portion was 1.44 and the background (BG) was 0.31, and no memory was generated. When the same evaluation was performed after 5000 sheets were continuously printed, the exposed portion potential was −75 V, the unexposed portion potential was −600 V, the ID was 1.42,
BG was 0.32, and there was no occurrence of memory.

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer containing at least a hole transfer agent, wherein an amine compound represented by the following general formula (1) is contained in the layer containing the hole transfer agent. And an dicyanovinyl compound. [Chemical 1] (In the formula, R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom, or an alkyl group or aryl group which may have a substituent, and Z represents a nitrogen-containing alicyclic structure. Represents an atomic group required for X is a hydrogen atom or a monovalent organic residue,
Y represents an organic residue. )