JPH07128894A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain a photoreceptor having stable performance independently of a change in temp. and humidity and ensuring high image quality and a long service life. CONSTITUTION:This photoreceptor has an intermediate layer 2 having 0.05-30.0mum thickness between the electric conductive substrate 1 and the photosensitive layer 3a contg. an org. photoconductive material. The intermediate layer 2 is formed by dispersing fine resin powder subjected to surface modification to conjugated polyene in a resin binder or modifying a resin layer of a homo- or copolymer of optionally modified vinyl halide or vinylidene halide to conjugated polyene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electrophotographic photosensitive member, and more particularly to an intermediate layer provided between a conductive support and a photosensitive layer containing an organic photoconductive material.

[0002]

2. Description of the Related Art An organic electrophotographic photosensitive member has a basic structure in which a conductive support made of an aluminum-based material and a photosensitive layer containing an organic photoconductive material are laminated. In such a structure, it is effective to provide a so-called intermediate layer that covers the surface of the conductive support in order to prevent image defects caused by defects on the surface of the conductive support. As the material of the intermediate layer, casein, polyvinyl alcohol, polyamide, melamine, insulating polymers such as cellulose,
Alternatively, conductive polymers such as polythiophene, polypyrrole, and polyaniline are known, and it is known that an anodized film formed by anodizing the surface of a support made of an aluminum-based material is used as an intermediate layer. Has been.

[0003]

Problems such as those listed below are required for such an intermediate layer. Structurally required properties include adhesion to the conductive support and the photosensitive layer,
The film strength of the intermediate layer itself may be mentioned. The electronically required characteristics are required to be stable with respect to changes in temperature and humidity, and to have appropriate electric conductivity to suppress an increase in the light portion potential of the photoconductor and hold the dark portion potential. The optically required characteristics include a performance capable of preventing an interference fringe pattern from being generated in an image even when monochromatic light is used as the exposure light. Further, in the case of an intermediate layer made of an organic material, resistance to a solvent used for coating and forming a photosensitive layer made of an organic material is required, and further, it is also required that the coating solution itself of the intermediate layer has high storage stability. To be done. In addition to these, it is also important that they can be easily and inexpensively formed from the viewpoint of productivity and commercial properties.

In order to solve the above problems, various organic materials as described above have been studied, and an insulating polymer containing a metal oxide powder dispersed therein may be used (see, for example, Japanese Patent Laid-Open Publication No. Sho. 63-298251), or using a conductive polymer containing a dopant (for example, JP-A-2-26036).
0) is proposed. However, when the insulating polymer coating film containing the metal oxide powder dispersed therein is used as the intermediate layer, the metal oxide powder should be uniformly dispersed and kept stable in the intermediate layer coating solution. Therefore, the distribution of the metal oxide powder in the coating film becomes non-uniform, and the electric conductivity of the intermediate layer tends to vary. Further, when a coating film of a conductive polymer is used as the intermediate layer, there are problems in coatability and smoothness of the surface of the intermediate layer. Also,
When an anodic oxide coating is used on a support made of an aluminum-based material, there are problems that it is difficult to select treatment conditions for stably forming a coating suitable as an intermediate layer and the manufacturing cost becomes high.

The present invention has been made in view of the above points, and is suitable for maintaining the dark portion potential by suppressing the increase of the light portion potential of the photosensitive member, which is stable with respect to changes in temperature and humidity. It has high electrical conductivity, excellent film strength and adhesion, has the ability to prevent interference fringes from appearing on images, and has an intermediate layer that can be formed easily and inexpensively. The object is to provide a photoreceptor having a long life.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a resin fine film whose surface is conjugated with polyene, between a conductive support and a photosensitive layer containing an organic photoconductive material. Film thickness of 0.0 containing powder dispersed in binder resin
The solution is to provide a photoreceptor having an intermediate layer of 5 μm to 30.0 μm.

The resin fine powder is a polymer or copolymer of a halogenated vinyl or vinylidene monomer,
And a modified polymer containing a halogenated vinyl or vinylidene monomer. When selecting the material for the resin fine powder, it is important to have resistance to the binder resin solvent that disperses them.
Particularly, it is preferable to use fluorine or chlorine as the halogen. The shape of the resin fine powder is preferably spherical or cylindrical.

The amount of the resin fine powder whose surface is conjugated polyene is contained in the intermediate layer is preferably 0.10 or more in terms of the volume fraction with respect to the total solid content of the intermediate layer. Examples of the binder resin used in the present invention include acrylic resins, styrene resins, polycarbonate resins, polyester resins, polyamide resins, and the like, and copolymers or crosslinked products of these resins, or silicone resins, melamine resins,
Examples thereof include phenolic, epoxy, acrylic, and other thermosetting resin groups, and copolymers of these resins.
In selecting the binder resin, it is important to have resistance to the solvent for the photosensitive layer coating liquid applied on the binder resin after coating and drying.

Further, the above-mentioned subject is selected from vinyl halides, vinylidene halides, and modified products thereof between a conductive support and a photosensitive layer containing an organic photoconductive material. It is also possible to solve the problem by providing a photoreceptor having an intermediate layer having a film thickness of 0.05 μm to 30.0 μm, which is obtained by copolymerizing or homopolymerizing a resin layer obtained by copolymerizing or homopolymerizing a resin with one as a monomer. As the halogen, chlorine is preferably used from the viewpoint of ease and cost when the intermediate layer is formed by the dipping method.

The surface of the resin fine powder and the conjugated polyene of the resin layer are formed by a heating method, a radiation irradiation method, a phase reaction method (eg, J. Po.
lym. Sci. , Polim. Chem. Ed. , 2
0 (1982) 3189) and the like, but the interphase reaction method is preferable from the viewpoint of uniformity of conjugated polyene formation, mass productivity, and cost.

[0011]

[Function] By forming an intermediate layer with a coating liquid in which a resin fine powder having a surface conjugated polyene is dispersed in a binder resin, the resin fine powder having a surface conjugated polyene is brought into contact with each other to form on the surface. The conductive polymer thus formed forms a three-dimensional electron conduction path, so that the electric conductivity of the intermediate layer sharply increases. Since this electrical conduction mechanism is electronically conductive, the electrical conductivity is stable against changes in the environment, especially changes in humidity, and the fluctuations in the light potential and the dark potential of the photoconductor are extremely small. In order to surely form a three-dimensional electron conduction path, it is preferable that the content of the resin fine powder is 0.10 or more in terms of volume fraction with respect to the total solid content of the intermediate layer.

As described above, since the binder resin is not directly involved in the electric conduction in the intermediate layer formed by applying the coating liquid in which the resin fine powder whose surface is conjugated polyene is dispersed in the binder resin, the binder is not directly involved. As the resin, it is possible to select a resin having good adhesion to the support and the photosensitive layer, excellent film strength, and resistant to the coating solution solvent for the photosensitive layer, regardless of the electrical characteristics.

The resin fine powders used in the present invention are all blackish brown, and therefore the intermediate layer containing the resin fine powders dispersed therein exhibits a black gray color, so that it is possible to prevent optical interference that causes interference fringes in an image. it can. Further, since the specific gravity of the resin fine powder whose surface is conjugated polyene is extremely close to the specific gravity of the binder resin, the coating solution for the intermediate layer is different from the case where the metal oxide powder or other semiconductor powder is dispersed and contained. In addition, it is possible to maintain a stable state for a long period of time without causing settling of powder.

On the other hand, in the case where the resin layer obtained by converting the resin layer into the conjugated polyene is used as the intermediate layer, the resin layer is converted into the conjugated polyene to form a three-dimensional electron conduction path in the resin layer. The electrical conductivity of is sharply increased. Since this electrical conduction mechanism is electronically conductive, the electrical conductivity is stable against changes in the environment, especially changes in humidity, and the fluctuations in the light potential and the dark potential of the photoconductor are extremely small. Further, the resin layer of the present invention is blackish brown, and it is possible to prevent optical interference that causes interference fringes in an image.

In the present invention, by making the surface of the resin fine powder into a conjugated polyene, or by making the resin layer into a conjugated polyene, it becomes insoluble in any solvent, so that the solvent for the coating liquid for the photosensitive layer is limited. Will disappear. The thickness of the intermediate layer is 0.05 μm to 30.0 μm in order to surely cover and conceal the surface defects of the support.
m is required.

[0016]

1 to 3 are schematic sectional views each illustrating a photoconductor according to the present invention. FIG. 1 shows a so-called negatively charged laminated type photoreceptor, in which an intermediate layer 2 is formed on a conductive support 1.
The photosensitive layer 3a is formed by stacking the charge generation layer 4 and the charge transport layer 5 in this order. FIG. 2 shows a so-called positive charging laminated type photoreceptor, which is a photosensitive layer 3b in which an intermediate layer 2, a charge transport layer 5 and a charge generation layer 4 are laminated in this order on a conductive support 1.
The protective layer 6 is provided. FIG. 3 shows a so-called positively charged single layer type photosensitive member, which has a structure in which an intermediate layer 2 and a single photosensitive layer 3c are provided on a conductive support 1. By using the intermediate layer 2 of each of these photoreceptors as the intermediate layer according to the present invention, it is possible to obtain a photoreceptor having excellent potential characteristics and image quality, the photosensitive layer being hard to peel off, and a long life.

The embodiments of the present invention will be described below with reference to the case of the negative charging laminated type photoreceptor of FIG. 1, but the present invention is not limited thereto. As the conductive support 1,
Generally, a cylinder made of an aluminum material or a vapor deposition film is used. The charge generation layer 4 is composed of a charge generation material and a binder resin. As the charge generating material, various phthalocyanine compounds, azo compounds, polycyclic quinone compounds, squarylium compounds, and derivatives thereof can be used. A specific example is shown below.

[0018]

[Chemical 1]

[0019]

[Chemical 2]

[0020]

[Chemical 3]

[0021]

[Chemical 4]

[0022]

[Chemical 5]

[0023]

[Chemical 6]

As the binder resin for the charge generation layer, polycarbonate, polyester, polyamide,
Polyurethane, epoxy, polyvinyl butyral, polyvinyl acetal, phenoxy resin, silicone resin,
Acrylic resin, vinyl chloride resin, vinylidene chloride resin,
A vinyl acetate resin, a homer resin, a cellulose resin, or a copolymer thereof is used, and a halide or cyanoethylated compound thereof is also used.

The charge transport layer 5 is composed of a charge transport material and a binder resin. As the charge transport material, various diamine compounds, hydrazone compounds, stilbene compounds, and their derivatives can be used. A specific example is shown below.

[0026]

[Chemical 7]

[0027]

[Chemical 8]

As the binder resin for the charge transport layer,
Polycarbonate, polystyrene, polyphenyl ether acrylic resin, etc. can be used. Example 1 30 parts by weight of polyvinyl chloride fine powder having an average particle size of 5 μm,
1 part by weight of tetra-n-butylammonium hydroxide was added to 300 parts by weight of an ethanol solution of 4N sodium hydroxide, and the mixture was heated and stirred at a temperature of 60 ° C. for 6 hours.
A resin fine powder (A) whose surface was conjugated polyene was obtained.

5 parts by weight of polyamide (trade name CM8000; manufactured by Toray Industries, Inc.) was dissolved in 30 parts by weight of methanol and 10 parts by weight of 1-butanol, and 1 part by weight of the above-mentioned conjugated polyene resin fine powder (A) was added to this solution. Parts were dispersed to prepare a coating liquid (1a) for the intermediate layer. This coating liquid (1a) was applied to an aluminum plate and dried to form a coating film having a film thickness of 10 μm, and its electric conductivity was measured. The temperature was 5 ° C., relative humidity 60%, temperature 20 ° C., relative humidity 60 %, Temperature 35
It was stable at 10 ^-7 S · cm ^-1 under each environment of ° C and relative humidity of 90%. Further, it was confirmed that even after the coating liquid (1a) was allowed to stand for one week, the resin fine powder did not aggregate or settle, and a good dispersion state was maintained.

Next, the compound 1-as a charge generating material
5 parts by weight of 1 and 5 parts by weight of polyvinyl acetal (trade name S-REC KS-1; manufactured by Sekisui Chemical Co., Ltd.) as a binder resin were mixed with 700 parts by weight of dichloromethane and kneaded with a mixer for 3 hours. A coating liquid (2) for the charge generation layer was prepared. Next, 1 part by weight of the compound 2-1 as a charge transport material and 1 part by weight of a polycarbonate (trade name Panelite L1225; manufactured by Teijin Chemicals Ltd.) as a binder resin were dissolved in 8 parts by weight of dichloromethane. A coating liquid (3) for the charge transport layer was prepared.

An aluminum alloy 6063 material was extruded to produce an outer diameter of 60 mm, a wall thickness of 1.0 mm, and a length of 3.
A 10 mm cylinder is ultrasonically cleaned with trichlene, and the outer surface is rubbed with a sponge while dripping an alkaline cleaning solution containing a surfactant, and then ultrasonically cleaned with warm pure water at 80 ° C and dried to form a conductive support. The coating liquid (1a) was applied onto this support by a dipping method to form an intermediate layer having a thickness of 20 μm. Subsequently, the coating solution (2) is applied thereon by a dipping method to form a charge generation layer having a film thickness of 0.2 μm, and the coating solution (3) is further applied thereon by a dipping method to obtain a film thickness of 20 μm.
A charge-transporting layer was formed as a photosensitive layer to prepare a photoreceptor.

Example 2 30 parts by weight of polyvinylidene fluoride fine powder having an average particle diameter of 1 μm and 1 part by weight of tetra-n-butylammonium hydroxide were dissolved in 4 parts of sodium hydroxide 4N ethanol solution 3
It was added to 100 parts by weight and heated and stirred at a temperature of 60 ° C. for 6 hours to obtain a resin fine powder (B) whose surface was conjugated polyene.

5 parts by weight of polyamide (trade name CM8000; manufactured by Toray Industries, Inc.) was dissolved in 40 parts by weight of methanol and 13 parts by weight of 1-butanol, and in this solution, a resin fine powder whose surface was conjugated polyene ( B) 1 part by weight was dispersed to prepare an intermediate layer coating solution (1b). This coating solution (1b) is applied to an aluminum plate and dried to give a film thickness of 10 μm.
When a coating film of m was formed and its electric conductivity was measured,
Temperature 5 ℃, relative humidity 60%, temperature 20 ℃, relative humidity 60
%, Temperature 35 ° C., relative humidity 90% 10 ⁻⁷ S under each environment
・ It was stable at cm ^-1 . In addition, 1 coating solution (1b)
It was confirmed that the resin fine powder did not aggregate or settle even after standing for a week, and a good dispersion state was maintained.

On a support similar to that used in Example 1,
The coating liquid (1b) was applied by a dipping method to form an intermediate layer having a film thickness of 3 μm. A photoconductive layer having a charge generation layer and a charge transport layer laminated thereon was formed thereon in the same manner as in Example 1 to prepare a photoconductor. Example 3 5 parts by weight of polyvinyl chloride having a number average molecular weight of 100,000 was dissolved in 40 parts by weight of tetrahydrofuran and 10 parts by weight of cyclohexanone to prepare a coating liquid (1c) for the intermediate layer.

This coating solution (1c) was applied on the same conductive support as used in Example 1 by the dipping method and dried at a temperature of 80 ° C. for 2 hours to form a resin layer having a film thickness of 10 μm. Subsequently, 1 part by weight of tetra-n-butylammonium hydroxide was dissolved in 300 parts by weight of an ethanol solution of 4N sodium hydroxide and immersed in a dehydrochlorination reaction solution at a temperature of 60 ° C. for 5 hours to make the resin layer a conjugated polyene. To form an intermediate layer.

On the intermediate layer thus formed, a photosensitive layer in which a charge generation layer and a charge transport layer were laminated was formed in the same manner as in Example 1 to prepare a photoreceptor. Further, the coating solution (1c) was applied to an aluminum plate and dried to obtain a film thickness of 10 μm.
m, a resin layer was formed, and subsequently, for the sample subjected to the conjugated polyene conversion as described above, at a temperature of 5 ° C. and a relative humidity of 60%,
60% relative humidity at 20 ° C, 9% relative humidity at 35 ° C
When the electric conductivity in each environment of 0% was measured, it was 1
It was stable at 0 ⁻⁷ S · cm ⁻¹ .

Comparative Example 1 8 parts by weight of polyamide (trade name CM8000; manufactured by Toray Industries, Inc.) was dissolved in 10 parts by weight of dichloromethane, 30 parts by weight of methanol and 10 parts by weight of 1-butanol, and the resulting solution had an average particle size of 0. 2 parts by weight of 1 μm fine titanium oxide powder was dispersed to prepare a coating liquid (1d) for the intermediate layer. This coating solution (1d) is applied to an aluminum plate and dried to obtain a film thickness of 10 μm.
When a coating film of m was formed and its electric conductivity was measured,
Temperature 5 ℃, relative humidity 60%, temperature 20 ℃, relative humidity 60
%, A temperature of 35 ° C., and a relative humidity of 90%, the temperature increases from 10 ⁻¹⁴ S · cm ⁻¹ to 10 ⁻¹² S · c as the humidity increases.
It changed in the range of m ⁻¹ and was unstable. In addition, the coating liquid (1
In d), the dispersion stability was poor, and sedimentation of the titanium oxide fine powder was observed after standing for several hours.

On a support similar to that used in Example 1,
The coating liquid (1d) was applied by a dipping method to form an intermediate layer having a film thickness of 10 μm. A photoconductive layer having a charge generation layer and a charge transport layer laminated thereon was formed thereon in the same manner as in Example 1 to prepare a photoconductor. Comparative Example 2 4 parts by weight of polyamide (trade name CM8000; manufactured by Toray Industries, Inc.) was dissolved in 10 parts by weight of dichloromethane, 30 parts by weight of methanol and 10 parts by weight of 1-butanol to prepare a coating solution (1e) for the intermediate layer. . This coating liquid (1e) is applied to an aluminum plate and dried to form a coating film having a film thickness of 10 μm,
When the electric conductivity was measured, it was found that the temperature was 5 ° C, the relative humidity was 60%, the temperature was 20 ° C, the relative humidity was 60%, the temperature was 35 ° C, and the relative humidity was 90%.
It varied in the range of ⁻¹⁴ S · cm ⁻¹ to 10 ⁻¹² S · cm ⁻¹ and was unstable.

On a support similar to that used in Example 1,
The coating liquid (1e) was applied by a dipping method to form an intermediate layer having a film thickness of 10 μm. A photoconductive layer having a charge generation layer and a charge transport layer laminated thereon was formed thereon in the same manner as in Example 1 to prepare a photoconductor. The electrophotographic characteristics of each photoconductor obtained as described above are evaluated. The photoconductor is installed in the laser printer,
A running test was performed to print an image on 50,000 sheets of A4 size paper under a normal temperature and normal humidity environment (R) at a temperature of 20 ° C. and a relative humidity of 60%, and changes in the light potential V _L and the dark potential V ₀ ,
The image obtained by reversal development was evaluated. Further, in a state where the photoconductor is mounted on the laser printer, under a normal temperature and normal humidity environment (R), a low humidity environment (L) at a temperature of 5 ° C. and a relative humidity of 60%, and a high temperature and a high temperature of 35 ° C. and a relative humidity of 90%. The image obtained by reversal development was evaluated after standing for 1 hour or more in a humid environment (H). Furthermore, JIS K54
The adhesiveness of the photosensitive layer was evaluated by a cross-cut test according to 00 8.5.1. The results of these evaluations are shown in Table 1.

The image was evaluated by performing solid printing on A4 size paper and judging according to the following criteria. Black points = Number of black points of 0.3 mm or less ×: 5 or more △: 4 to 2 ○: 1 or less Overburden = Occurrence of overburden ×: Remarkable △: Slight ○: None Interference = Image defect due to interference ×: Remarkable △: Slight ◯: None In addition, the adhesion was judged according to the following criteria.

Cross-cut test ×: 50% or more peeling Δ: 50% or less peeling ○: No peeling

[0042]

[Table 1]

As can be seen in Table 1, Examples 1, 2, 3
Each photoreceptor initial light potential V _L is small, 50,000 sheets of but little change in the running test light potential V _L even after, the photoreceptors of Comparative Examples 1 and 2 the initial light potential _VL is large, and the bright part potential _VL is greatly changed by the running test. The dark portion potential V ₀ is corrected by the correction mechanism of the printer so as to be constant at −600 V, and therefore does not change as a measured value. However, in each of the photoconductors of the comparative examples, the change in the light portion potential V _L is seen. Dark part potential V ₀
Is considered to have changed significantly. Also in image quality evaluation, after running test and after leaving in each environment,
The image quality of the photoconductor of the example is better than that of the photoconductor of the comparative example, and the photoconductor of the example also has good adhesion of the photosensitive layer.

[0044]

According to the present invention, an intermediate layer provided between a conductive support and a photosensitive layer containing an organic photoconductive material is used, and a resin fine powder whose surface is conjugated polyene is contained in a binder resin. Film thickness of 0.05 μm to 3 dispersedly contained in
The layer has a thickness of 0.0 μm. Alternatively, a resin layer obtained by copolymerizing or homopolymerizing an intermediate layer with a vinyl halide, vinylidene halide, or a modified product thereof as one of monomers is conjugated polyene, and has a thickness of 0. The layer has a thickness of 05 μm to 30.0 μm. Such a layer can reliably cover defects on the surface of the support,
It has stable and suitable electric conductivity with respect to changes in temperature and humidity, can prevent optical interference with grayish black, is excellent in film strength and adhesion, and can be easily and inexpensively formed. By using such a layer as an intermediate layer, it is possible to obtain a photoreceptor having a high image quality and a long life, which functions stably even with respect to changes in temperature and humidity, easily and inexpensively.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of a photoconductor according to the present invention.

FIG. 2 is a schematic cross-sectional view of another embodiment of the photoconductor according to the present invention.

FIG. 3 is a schematic sectional view of still another embodiment of the photoconductor according to the present invention.

[Explanation of symbols]

 1 Conductive Support 2 Intermediate Layers 3a, 3b, 3c Photosensitive Layer 4 Charge Generation Layer 5 Charge Transport Layer 6 Protective Layer

Claims (5)

[Claims] 1. A film thickness of 0. 0, which is obtained by containing resin fine powder whose surface is conjugated polyene is dispersed in a binder resin between a conductive support and a photosensitive layer containing an organic photoconductive material.
An electrophotographic photoreceptor having an intermediate layer of from 05 μm to 30.0 μm. 2. The resin fine powder is polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride,
2. The electrophotographic photosensitive member according to claim 1, which is selected from the group consisting of these copolymers and modified products. 3. The electrophotographic photosensitive material according to claim 1 or 2, wherein the volume fraction of the resin fine powder whose surface is conjugated with polyene is 0.10 or more based on the total solid content of the intermediate layer. body. 4. A monomer selected from vinyl halides, vinylidene halides, and modified compounds thereof is used as a monomer between a conductive support and a photosensitive layer containing an organic photoconductive material. An electrophotographic photoreceptor comprising an intermediate layer having a film thickness of 0.05 μm to 30.0 μm, which is formed by forming a conjugated polyene into a copolymerized or homopolymerized resin layer. 5. The electrophotographic photosensitive member according to claim 4, wherein one of monomers selected from vinyl chloride, vinylidene chloride, and modified compounds thereof is used.