JPH06102682A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body excellent in sensitivity characteristics and durability. CONSTITUTION:A compd. represented by formula I and a compd. represented by formula II are incorporated into an electric charge transferring layer. In the formula I, each of R1, R1' and R1'' is H, alkyl or aryl, each of R2, R3, R2', R3', R2'' and R3'' is H, alkyl, aryl, alkenyl or a heterocyclic group and R2 and R3 and/or R2' and R3' and/or R2'' and R3'' may form a ring in combination with an adjacent C atom. In the formula II, 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 containing a specific trifunctional compound and a specific amine compound in a charge transport layer and having excellent sensitivity characteristics and durability. Is.

[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. OPC that has sensitivity to long-wavelength light including near-infrared light due to development of dye molecular design and pigment design
Has been developed and is being actively researched for use in optical printers and digital copying machines using semiconductor lasers and LEDs as light sources. However, in OPC, there remain problems in sensitivity and durability, and OPC having high sensitivity and high durability is desired. Various methods have been proposed as means for improving the sensitivity of OPC, but at present, a function-separated OPC having a two-layer structure in which the functions are separated into a charge generation layer and a charge transport layer is mainly used. For example, the charge generated in the charge generation layer by exposure is injected into the charge transport layer, transported through the charge transport layer and transported to the surface, and neutralizes the surface charge to cause OPC.
An electrostatic image is formed on the surface. The function-separated type is less likely to trap the generated charges than the single-layer type, and the charges can be efficiently transported to the surface without hindering the functions of the respective layers.

As the organic charge generating agent used in the charge generating layer, a compound which absorbs the energy of irradiation light and efficiently generates charges is used.
Azo pigments (JP-A-54-14967), metal-free phthalocyanine pigments (JP-A-60-143346), metal phthalocyanine pigments (JP-A-50-16538), squarylium salts (JP-A-53) -27033 gazette) and the like.

As the charge transfer agent used in the charge transfer layer, it is necessary to select a compound having a high charge injection efficiency from the charge generation layer and a high charge mobility in the charge transfer layer. Therefore, a compound having a small ionization potential or a compound which easily generates radical cations is selected. For example, a triarylamine derivative (Japanese Patent Laid-Open No. 53-47).
260), hydrazone derivatives (JP-A-57-101844), oxadiazole derivatives (JP-B-34-5466), pyrazoline derivatives (JP-B-52-4188), stilbene derivatives (JP-A-SHO). 58-198043), triphenylmethane derivative (Japanese Patent Publication No. 45-555), 1,3-butadiene derivative (Japanese Patent Publication No. 62-287257), etc., but their charge mobility is small. Satisfactory sensitivity was not obtained. To solve these problems, it has been proposed that an OPC having a large charge mobility and excellent sensitivity characteristics can be obtained by using a tristyryl derivative as a charge transporting agent (JP-A-2-84657).

However, the OP thus obtained
C was not satisfactory in terms of durability. That is, during repeated use in an electrophotographic apparatus, changes such as a decrease in charging potential, an increase in residual potential, a decrease in sensitivity characteristics, etc. occur, making it unusable. Not all of the causes of these changes have been clarified, but one of the main causes is oxidative deterioration of the charge transfer agent.
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, charge transfer is hindered, causing a decrease in charging potential and an increase in residual potential, resulting in a photoreceptor having a short life.

For such oxidative deterioration, for example, Japanese Unexamined Patent Publication No.
-122444 and JP-A-1-200261 describe that a hindered phenol-based antioxidant is added to prevent characteristic deterioration. However, in the OPC using the above-mentioned tristyryl derivative as the charge transport agent, the stabilizing effect of these antioxidants cannot be said to be sufficient.
The deterioration of electrophotographic characteristics such as increase of residual potential and decrease of sensitivity,
Printing quality is degraded due to memory generation and resolution degradation, making it unusable for practical use. Under the present circumstances, an OPC satisfying both high sensitivity and high durability has not yet been obtained. Therefore, an object of the present invention is to provide an organic electrophotographic photosensitive member that satisfies both high sensitivity and high durability.

[0007]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the inclusion of a tristyryl derivative and a specific amine compound in the charge-transporting layer makes it possible to obtain an electron having excellent sensitivity characteristics and durability. The inventors have found that a photographic photosensitive member can be obtained, and completed the present invention. That is, the present invention provides a general formula (1) for an electrophotographic photosensitive member including a conductive substrate, a charge generation layer and a charge transport layer as essential components.

[0008]

[Chemical 3]

(Wherein R ₁ , R ₁ 'and R ₁ "are the same or different and each is a hydrogen atom, an optionally substituted linear or branched alkyl group, or an optionally substituted aryl group. It represents _{either, R 2, R 3, R} 2 ', R 3', R 2 ", R 3"
Are the same or different, a hydrogen atom, an optionally substituted linear or branched alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group,
Represents any of optionally substituted heterocyclic groups, or R ₂ and R ₃ and / or R ₂ 'and R ₃ ' and / or R ₂ "
R ₃ "forms a ring with the adjacent carbon atom.), And a general formula (2)

[0010]

[Chemical 4]

(In the formula, R ₄ , R ₅ , R ₆ and R ₇ 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 a group of atoms necessary for formation, X represents a hydrogen atom or a monovalent organic residue, and Y represents an organic residue.) In the charge transport layer. An electrophotographic photoreceptor is provided.

In the above general formula (1), R ₁ , R ₁ ', R ₁ "
Of these, a hydrogen atom is preferable. And R ₂ and R ₃ , R ₂ '
It is preferable that one of R ₃ ', R ₂ "and R ₃ " is a hydrogen atom and the rest is an aryl group. Further, the above general formula (2)
In the above, as R ₄ , R ₅ , R ₆ and R ₇ , a hydrogen atom or an alkyl group having 3 or less carbon atoms is particularly preferable. Also, Z is N
The nitrogen-containing alicyclic structure formed together with is preferably a 5- to 7-membered ring, particularly a 6-membered ring having C as a main constituent atom and containing N 2. X is preferably a hydrogen atom or an alkyl group having 3 or less carbon atoms or an acyl group.

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

[0014]

[Chemical 5]

[0015]

[Chemical 6]

[0016]

[Chemical 7]

[0017]

[Chemical 8]

[0018]

[Chemical 9]

[0019]

[Chemical 10]

The compounds represented by the general formula (1) are 2
It is also possible to use a mixture of two or more species. The total content in the charge transport layer is preferably 20 to 80% by weight, particularly preferably 30 to 70% by weight. Specific examples of the compound represented by formula (2) used in the present invention are shown below, but the present invention is not limited thereto.

[0021]

[Chemical 11]

[0022]

[Chemical 12]

[0023]

[Chemical 13]

[0024]

[Chemical 14]

The compounds represented by the general formula (2) are 2
It is also possible to use a mixture of two or more species. The total content in the charge transport layer is preferably 0.1 to 20% by weight. When the compound represented by the general formula (1) or the compound represented by the general formula (2) is out of the above range, sufficient sensitivity characteristics and durability cannot be obtained.

The electrophotographic photosensitive member provided by the present invention comprises:
The basic structure is a laminated-type photoreceptor in which a charge generation layer containing a charge generating agent as a main component and a photosensitive layer consisting of a charge transporting agent and a binder as a main component are provided on a conductive substrate. 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 0.01 to 5 μm.

The charge transport layer used in the present invention is
At least a compound represented by the general formula (1) and a general formula
The compound represented by (2) can be dissolved and coated in a solvent together with a binder to obtain a coating film. The binder for the charge transport layer is not particularly limited as long as it is an electrically insulating resin and has excellent compatibility with the charge transport agent to be used, and examples thereof include polycarbonate and polyarylate. , Polyester, polyamide, polyacrylate, polymethacrylate, polystyrene, styrene-acrylic copolymer, polyacrylonitrile, polyacrylamide, acrylonitrile-butadiene copolymer, polysulfone, polyethersulfone, silicone resin, phenoxy resin, urethane resin, thermosetting Epoxy resin or a mixture of two or more of these resins can be used. The weight ratio of the charge transport agent to the binder in the charge transport layer is preferably 10:90 to 90:10, and particularly preferably 30:70 to 70:30. Charge transport layer thickness is 10-40μ
m is preferred.

[0033]

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. 40 parts of the tristyryl compound represented by the formula (A-6), 1.5 parts of the amine compound represented by the formula (B-8), 40 parts of polycarbonate-Z (Z-500, manufactured by Teijin Chemicals Ltd.) are 1,2- It was dissolved in 420 parts of dichloroethane to obtain a charge transport layer coating material. This coating material was applied onto the above charge generation layer by a dip coating method and dried to obtain a charge transport layer having a film thickness of 20 μm.

The electrophotographic characteristics of the drum-shaped electrophotographic photosensitive member produced as described above were evaluated using a photosensitive drum characteristic tester. As a result, the surface potential V ₂ after being charged to −700 V by the corona charging method and left in the dark for 2 seconds was −690 V. Then, the semiconductor laser with an oscillation wavelength of 780 nm was irradiated to obtain the half-exposure amount E _1/2, which was 0.22 μJ / cm ² .
Residual potential V _R was -3 V. Next, it was attached to a commercially available reversal development type laser beam printer and a printing test was conducted. As a result, the print density (ID) of the solid black portion was 1.47 (measured with a Macbeth densitometer), and the background (BG) was 0.
It was 25 (color difference meter 1001DP, made by Nippon Denshoku Industries). Performing the same evaluation after continuous printing of 5000 sheets, ID and BG respectively
It was 1.46 and 0.30, and when V ₂ , E _1/2 and V _R were measured, they were −680V, 0.24 μJ / cm ² and −5V, respectively.

Examples 2 to 5 Photosensitive members 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 compound represented by the general formula (2). The results are shown in Table 1.

[0037]

[Table 1]

Examples 6 to 9 Table 2 shows the tristyryl compounds represented by the general formula (1).
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the compound shown in 1 was used. The results are shown in Table 2.

[0039]

[Table 2]

Comparative Example 1 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the amine compound represented by the formula (B-8) was not added. As a result, V ₂ , E _1/2 , V
_R is -680V, 0.21μJ / cm ² , -3V, respectively,
The ID and BG were 1.48 and 0.30, respectively. When the same evaluation is performed after continuous printing of 5000 sheets, ID and BG are 1.36 and 0.9, respectively.
0, V ₂ , E _1/2 and V _R were −630V, 0.30 and −15V, respectively.

Comparative Example 2 An electron was prepared in the same manner as in Example 1 except that a phenol compound represented by the following formula (PH-1) was added in place of the amine compound represented by the formula (B-8). A photographic photoreceptor was prepared and evaluated. As a result, V ₂ , E _1/2 , and V _R are −680V, 0.30 μJ / cm ² , and −20V, respectively, and ID,
BG was 1.34 and 0.36, respectively. When the same evaluation is performed after continuous printing of 5000 sheets, ID and BG are 1.25, 1.0,
V ₂ , E _1/2 and V _R were −630V, 0.35 and −40V, respectively.

[0042]

[Chemical 15]

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive substrate, a charge generation layer and a charge transport layer as essential components, wherein the compound represented by the general formula (1): (In the formula, R ₁ , R ₁ 'and R ₁ "are the same or different,
Represents a hydrogen atom, an optionally substituted linear or branched alkyl group, or an optionally substituted aryl group, and represents R ₂ , R ₃ , R ₂ ', R ₃ ', R ₂ ", R ₃ "are the same or different and each is a hydrogen atom, an optionally substituted linear or branched alkyl group, an optionally substituted aryl group,
Represents an optionally substituted alkenyl group, an optionally substituted heterocyclic group, or R ₂ and R ₃ and / or R ₂ 'and R ₃ ' and / or R ₂ "and R ₃ "Forms a ring with adjacent carbon atoms. ) And a compound represented by the general formula (2): (In the formula, R ₄ , R ₅ , R ₆ and R ₇ 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 required for X is a hydrogen atom or a monovalent organic residue,
Y represents an organic residue. ) A compound represented by the formula (4) is contained in a charge transport layer, which is an electrophotographic photoreceptor.