JPH0363658A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To eliminate accumulation of stress strains at the time of winding a sheet or belt type photosensitive body on a cyclindrical core material and to prevent damage to the characteristics of the photosensitive body due to cracks of a coating film by forming a backcoat layer specified in the surface roughness. CONSTITUTION:This photosensitive body is formed by coating the surface of a flexible support 1 with a photosensitive layer 2, and the reverse side is coated with the backcoat layer 5 containing fine particles 51, preferably, having an average particle diameter of 0.1 - 10 mum, dispersed into a binder resin 52, and having a surface roughness Rz of 0.1 - 10 mum. For example, this backcoat layer 5 is formed by coating the reverse side of a polyethylene terephthalate film with a coating fluid prepared by dispersing silicon oxide particles specified in the particle diameter into polycarbonate through an extrusion die.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sheet-like or belt-like electrophotographic photoreceptor.

2. Description of the Related Art Sheet-like or belt-like electrophotographic photoreceptors are generally made of a flexible support such as a polyethylene terephthalate film with a photosensitive layer coated on one side. When manufacturing a sheet-like or belt-like electrophotographic photoreceptor, a photosensitive layer coating is formed on a flexible support using an extrusion die, etc., and then wound around a cylindrical core material. It is being

Problems to be Solved by the Invention By the way, in conventional sheet-like or belt-like electrophotographic photoreceptors, the back surface of the support has a surface roughness Rz (10-point average roughness) of 0.1 to less than 0.1. When a sheet-like or belt-like electrophotographic photoreceptor is wound around a core material, mechanical distortion occurs due to the phenomena described below in ■ and ■.
There is a problem in that this causes significant damage to the characteristics of the photoreceptor, such as causing destruction of the coating film. ■Due to high friction between the coating films, the tension applied to the photoreceptor layer during winding is not equalized.■After winding, the support is deformed due to shrinkage, which causes high friction of the coating film. Not relieved for.

Therefore, the present invention has been made in view of the above-mentioned problems in the conventional technology.

That is, an object of the present invention is to provide an electrophotographic photoreceptor in which the above-mentioned drawbacks of conventional sheet-like or belt-like electrophotographic photoreceptors are improved.

Means for Solving the Problems The above-mentioned object of the present invention is to provide a back coat layer having fine irregularities on the back surface of the support in a sheet-like or belt-like electrophotographic photoreceptor, and to reduce friction when winding it around a cylindrical core material. This is achieved by reducing the coefficient.

The present invention provides a sheet-like or belt-like electrophotographic photoreceptor having a photosensitive layer coating on the surface of a flexible support.
It is characterized in that a back coat layer is provided on the back surface of the support, which is made of fine particles dispersed in a binder resin and has a surface roughness Rz of 0.1 to 10 m.

Hereinafter, the sheet-like or belt-like electrophotographic photoreceptor of the present invention will be described in detail.

FIG. 1 is a schematic cross-sectional view of an example of the electrophotographic photoreceptor of the present invention. The support 1 has a conductive layer U, on which a charge generation layer 2 is applied via a charge injection blocking layer 3 and an adhesive layer 4.
(And a photosensitive layer 2 consisting of a charge transport layer 22 is provided.On the other hand, on the back side of the support, fine particles 51 are formed on a binder resin 5.
A back coat layer 5 dispersed in two is formed.

As the support in the electrophotographic photoreceptor of the present invention, a flexible sheet or belt-shaped plastic film imparted with conductivity is used.

For example, metal foil such as aluminum, nickel, chromium, aluminum, titanium, nickel, chromium, 5U
A plastic film or sheet such as a polyethylene terephthalate film provided with a deposited layer of S1 gold, vanadium, tin, indigo oxide pigment, etc. can be used.

In the present invention, it is preferable to use an organic photosensitive material for the photosensitive layer in order to provide flexibility, but the photosensitive layer may also be formed by dispersing highly sensitive inorganic photoconductive particles in a binder resin. good. Further, the photosensitive layer may be of a functionally separated type in which the photosensitive layer is separated into a charge generation layer and a charge transport layer as shown in FIG.

In that case, the charge generating materials used in the charge generating layer include azo pigments, phthalocyanine pigments, polycyclic bovine non-pigments, perylene pigments, indigo pigments, quinacridone pigments,
Examples include zinc oxide and trigonal selenium.

Furthermore, examples of the charge transport material used in the charge transport layer include known materials such as amine compounds, hydrazone compounds, pyrazoline compounds, oxadiazole compounds, and carbazole compounds.

Many of the above materials do not have film-forming properties themselves, so a binder resin is used when forming the layer. As the binder resin, polycarbonate, polyester, polystyrene, styrene-acrylonitrile copolymer, polymethacrylate ester, styrene-methacrylate ester copolymer,
Polyvinyl butyral, vinyl acetate polymers or copolymers, cellulose esters or ethers, polybutadiene, polyurethane, epoxy resins, etc. are used.

In addition, when using a photosensitive resin that itself has photosensitivity and film-forming properties, such as polyvinyl carbazole,
It can be used alone without using other resins.

In the present invention, an adhesive layer or a charge injection blocking layer may be provided between the photosensitive layer and the support to improve adhesion.

In the present invention, the back coat layer provided on the back surface of the support is formed by dispersing fine particles in a binder resin, and has a rough surface with fine irregularities formed on the surface. Surface roughness Rz (10 point average roughness) is 0.1
It is necessary to be within the range of ~10 m. In addition, in this specification, the surface roughness Rz is a ten-point average roughness, and in a portion extracted by a reference length from a cross-sectional curve,
The average value of the elevation of the highest to fifth mountain peaks measured in the direction of vertical magnification from a straight line that is parallel to the average line and does not cross the cross-sectional curve, and the average value of the elevation from the deepest to the fifth valley floor. It means the value of the difference expressed in micrometers (111 m). If the surface roughness is less than 0°Lm, friction will increase, making it impossible to alleviate the strain and stress that occurs when the material is wrapped around the cylindrical core material, which may cause damage such as destruction of the paint film. Give to the membrane. Moreover, if it exceeds IOa, the frictional force decreases too much, resulting in inconveniences such as winding misalignment when winding around the core material.

In the present invention, fine particles may be dispersed in the binder resin in order to provide the surface of the back coat layer with fine irregularities, but the material and particle size of the particles must be selected so as not to cause a decrease in coating film adhesion. No, it does not obstruct the transmission of static electricity removal light from the back side, etc.
It is necessary to select a material that does not inhibit the photoreceptor properties.

Materials for the fine particles that can be used in the present invention include silicon oxide (S i02 ), silicon oxide surface-treated with a silane coupling agent, such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane. Silane and other alkoxysilanes, hexamethyldisilazane and other silazane, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glyside Xypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ
- treated with a silane coupling agent such as ureidopropyltriethoxysilane;
metal oxides such as O), and polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, ethylene-fluoroethylene copolymer, tetrafluoroethylene Examples include fluororesins such as ethylene-perfluoroalkyl vinyl ether copolymers.

Further, the average particle diameter of these fine particles is preferably in the range of 0.1 to 104.

As the binder resin for dispersing the above fine particles, polycarbonate, polyester, polystyrene, styrene-
Acrylonitrile copolymers, polymethacrylic acid esters, styrene-methacrylic acid ester copolymers, polyvinyl butyral, vinyl acetate polymers or copolymers, cellulose esters or ethers, polybutadiene, polyurethane, epoxy resins, etc. can be used, but in particular polycarbonate is preferred.

The blending amount of the fine particles is preferably 0.5 to 5% by weight based on the binder resin polycarbonate.

The coating film can be formed by applying a coating liquid containing the above-mentioned fine particles and a binder resin by a well-known method.

The coating film is preferably formed to have a thickness in the range of 10 to 20 mm.

Example Next, the present invention will be explained by examples.

Example 1 A charge injection blocking layer with a thickness of 0.05 m made of a silane coupling agent and a polyester resin (manufactured by DuPont, 49000) were placed on a support with a thickness of 70 mm formed by vapor-depositing titanium on the surface of a polyethylene terephthalate film. 10 parts of trigonal selenium, 50 parts of poly(N-vinylcarbazole) and N,N
'-diphenyl-N,N'-bis(3-methylphenyl)-0,1'-biphenyl]-4,4'-diamine 50
50 parts of polycarbonate resin (Macrolon, manufactured by Mobay) and N.

N'-diphenyl-N,N'-bis(3-methylphenyl)-0,1'-biphenyl]-4,4'-diamine 5
A charge transport layer having a thickness of 25 m and consisting of 0 parts was laminated.

On the other hand, on the back side of the support, a film made of silicon oxide (SiO□) and polycarbonate resin had a thickness of 15 g and a surface roughness Rz: L.
A back coat layer of Oa was formed. This back coat layer was formed as follows.

That is, a coating liquid in which silicon oxide with an average particle size of 10 m was added and dispersed in a polycarbonate resin (Macrolon, manufactured by Mobay Co., Ltd.) in an amount of 1% by weight based on the polycarbonate resin was applied onto the back surface of the support. It was applied by a strusion die and dried with heated air at 100°C.

The electrophotographic photoreceptor produced as described above was
After being left wrapped around a 50 m cylindrical core material for 24 hours, a copying operation was performed using a conventional method to create an image, and the image was evaluated. As a result, no image quality failures caused by paint film destruction were observed.

Example 2 As a back coat layer of the electrophotographic photoreceptor shown in Example 1, 1% by weight of silicon oxide (Si02) having an average particle size of 0.1 to 0.1 was dispersed in a polycarbonate resin (Macrolon, manufactured by Mobay). An electrophotographic photoreceptor having the same structure as in Example 1 was prepared, except that it had a rough surface with a surface roughness of 0.1 m, and image evaluation was performed in the same manner.

As a result, no image quality defects were observed.

Example 3 The back coat layer of the electrophotographic photoreceptor shown in Example 1 was made by dispersing 1% by weight of polyvinylidene fluoride with an average particle size of 5a in polycarbonate resin (Macrolon, manufactured by Mobay Co., Ltd.) to improve the surface roughness. An electrophotographic photoreceptor having the same structure as in Example 1 was prepared except that a rough surface with a diameter of 0.4- was formed, and image evaluation was performed in the same manner.

As a result, no image quality defects were observed.

Comparative Example 1 The same method as in Example 1 was used, except that the back coat layer of the electrophotographic photoreceptor shown in Example 1 did not contain silicon oxide and had a surface roughness of 0.08IIIa. Create an electrophotographic photoreceptor having the following configuration,
Image evaluation was performed in the same manner. As a result, image quality defects due to paint film destruction were observed.

Comparative Example 2 The back coat layer of the electrophotographic photoreceptor shown in Example 1 had a rough surface with a surface roughness of 20s formed by dispersing fine particles of silicon oxide (Si02) with an average particle size of 15. When an electrophotographic photoreceptor having the same configuration as in Example 1 was produced except for this, the film formation of the thin coating layer was not uniform, and the friction was too low when it was wound around a cylindrical core material. This caused inconveniences such as misalignment of the winding.

Effects of the Invention The sheet-like or belt-like electrophotographic photoreceptor of the present invention has fine particles dispersed in the back coat layer of the support to form a rough surface having a predetermined surface roughness, as described above. As a result, there is no accumulation of stress and strain when the material is wound around a cylindrical core material, and therefore, damage to the photoreceptor properties due to paint film breakage can be prevented.

52...Binder resin.

Claims (2)

[Claims] (1) In a sheet-like or belt-like electrophotographic photoreceptor having a photosensitive layer coating on the surface of a flexible support, fine particles are dispersed in a binder resin on the back surface of the support,
A sheet-like or belt-like electrophotographic photoreceptor comprising a back coat layer having a surface roughness Rz of 0.1 to 10 μm. (2) The sheet-like or belt-like electrophotographic photosensitive material according to claim 1, wherein the fine particles in the back coat layer provided on the back surface of the support have an average particle size of 0.1 to 10 μm. body.