JPH03259267A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an image generating no interference pattern by forming a rough surface within the specific range on an electroconductive base surface and forming an anodic oxide film without alkaline or acid cleaning. CONSTITUTION:Without using alkaline or acid cleaning as a pretreatment on an A alloy substrate 1 having a surface 3a with a predetermined roughness by machining, the anodic oxide film 2a prepared in flat film forming conditions in the surface is provided. Without using the alkaline or acid cleaning as a pretreatment on the substrate 1, by forming the anodic oxide film 2a, the surface roughness of the surface does not change before or after the film forming and the rough surface in the range of 0.6-4.0mum by Rmax. is maintained. On the substrate surface, light beams of 660-800nm in wavelengths from the light source of a printer is reflected irregularly, so no intereference occurs between the reflected light on the substrate surface and the reflected light on the film sur face, even when the light beams pass through the anodic oxide film. Hence generation of the interference pattern of image is prevented.

Description

Detailed Description of the Invention [Industrial Application Field] This invention provides a charge generation layer made of an organic material on a conductive substrate made of aluminum or an aluminum alloy;
The present invention relates to a method of manufacturing an electrophotographic photoreceptor in which charge transport layers made of organic materials are sequentially laminated, and more particularly to a method of surface treatment of a conductive substrate.

[Conventional technology]

Electrophotographic photoreceptors using organic materials are required to meet demands such as high sensitivity, repeated characteristic stability, and durability.
Generally, it has a functionally separated laminated structure having a photosensitive layer formed by coating a charge generation layer and a charge transport layer in this order on a conductive substrate.

Aluminum alloys have traditionally been widely used for the conductive substrates of photoreceptors for electrophotography, and currently, aluminum alloys are mainly used as aluminum alloys.
3, ^6063, or a special 1m-thick aluminum alloy that takes workability into consideration.

When manufacturing a photoreceptor using an organic material using a conductive substrate made of these aluminum alloys, a charge generation layer is coated on the substrate to a thin thickness on the order of submicrons, and a charge transport layer is formed on top of the charge generation layer. is formed with a film thickness of 10 μm to 30 μm. In order to provide a photoreceptor capable of producing high-quality electrophotographic images, the charge generation layer must be a very uniform film free from entrapped foreign matter. Therefore, high cleanliness is required for the surface of the substrate.

If foreign matter is present on the surface of the substrate and uneven areas are formed in the charge generation layer, black spots will appear on the resulting image. However,
Even when using a substrate that has been cleaned to the point where the presence of foreign matter is almost negligible, minute black spots may appear on the image in a high-temperature environment. This is said to be due to charge carriers being injected from the conductive substrate into the charge generation layer, and in order to suppress this charge carrier injection, a charge injection blocking layer having a required resistance value is provided at the interface between the substrate and the charge generation layer. Many have them. Known charge injection blocking layers include relatively low-resistance resin films such as polyamide coated on a substrate, and anodized films formed by anodizing the surface of an aluminum alloy substrate. ing. Among these, the film quality, resistance, etc. of the anodic oxidation film of aluminum alloy can be controlled by film formation conditions (opening oxidation conditions, sealing treatment conditions). In order to form an anodic oxide film suitable as a charge injection blocking layer, the film formation conditions are limited to a relatively narrow range, but the resulting film is not only suitable as a charge injection blocking layer but also hard and has a good film quality. It has been widely used since it is stable and easy to handle.

However, the anodic oxide film of the aluminum alloy suitable as the charge injection blocking layer described above is transparent in the wavelength range (660 nm to 800 nm) of the light source often used in electrophotographic printers, so it cannot be used as an electrophotographic image as described below. The above problem arises. That is, the average thickness of the anodic oxide film formed on the surface of the conductive substrate made of an aluminum alloy of the photoreceptor is about 5 μm to 10 μm. If this film is transparent to the wavelength of the printer's light source, part of the light incident on the photoconductor will be reflected by the surface of the anodic oxide film on the substrate, and some will be transmitted through the anodic oxide film and will pass through the aluminum alloy surface of the substrate. reaches and reflects there. These two reflected lights cause interference due to an optical path difference caused by the thickness of the anodic oxide film. Since this interference occurs at the interface between the charge generation layer and the substrate, a problem arises in that an interference pattern is generated on the image based on the same principle as a moiré pattern. This interference pattern must not exist in terms of image quality, and many efforts have been made to prevent this. One of these methods is to increase the roughness of the film surface by controlling the film formation conditions when forming the anodic oxide film on the substrate surface, and scatter the incident light on the film surface. In this method, when forming an anodized film on a porous film, the surface of the porous film is colored with a pigment before sealing treatment to form a colored film that is opaque to incident light.

[Problem to be solved by the invention]

However, among these methods, in the former method, the surface to which the charge generation layer is applied is rough, making it difficult to stably form a good coating film, resulting in deterioration of electrical characteristics. Furthermore, since the surface of the substrate is rough and has a large surface area, foreign matter tends to adhere to it, deteriorating the appearance quality of the photoreceptor and increasing the number of image defects. Also, in the latter
There have been problems in that the coloring pigment affects the characteristics of the photoreceptor, the electrical characteristics of the photoreceptor vary significantly depending on the sealing treatment conditions, and sometimes there is no light attenuation.

The present invention solves the above-mentioned problems, provides high-quality images with almost no black spots, and has a resolution of 660 nm to 660 nm.
An object of the present invention is to provide a method for manufacturing an organic electrophotographic photoreceptor that can produce images without interference patterns even when used in a printer that uses a light source with a wavelength in the 800 nm range.

[Means to solve the problem]

According to the present invention, the above-mentioned problem can be solved by an electrophotographic photoreceptor comprising a conductive substrate made of aluminum or an aluminum alloy, a charge generation layer made of an organic material, and a charge transport layer made of an organic material sequentially laminated. No l! ! Depending on the manufacturing method, the maximum height Rmax of the conductive substrate surface is 0.6 μm.
The surface is roughened to within a range of 4.0 μm or less, and the surface is anodized without performing alkaline cleaning or acid cleaning as pretreatment, and then sealed to form an anodized film. This problem can be solved by using a manufacturing method in which the charge generation layer and the charge transport layer described above are sequentially laminated thereon.

The conductive substrate surface can be roughened by mechanical means such as cutting, grinding, sandblasting, and liquid honing.
This can be suitably carried out to obtain the optimum roughness.

[Effect]

By forming an anodic oxide film on the substrate without performing alkaline cleaning or acid cleaning as pre-treatment, the surface shape of the substrate does not change before and after film formation, and Rm
A rough surface of 0.6 μm or more and 4.0 μm or less in ax is maintained. For substrate surfaces whose Rmax is 0.6 μm or more and 4.0 μm or less, the wavelength of the printer's light source is 660 nm.
Since light of ~800 nm is diffusely reflected, even if the anodic oxide film transmits this light, there will be no interference between the light reflected on the substrate surface and the light reflected on the film surface. Therefore,
Since interference patterns will not occur in the image, the substrate surface will be
This means that it is possible to form a film that has a film quality that is optimal for blocking charge injection and has a flat surface without considering transparency to light of the above wavelengths or roughening of the film surface. Pigments for coloring the film are not required and their influence is eliminated, and a uniform charge generation layer can be stably coated and formed on the flat surface of the film. Thus, it has a good charge injection blocking layer and a charge generation layer, has almost no black spots, and has a wavelength of 6.
Even when used in a printer using a light source of 60 nm to 800 nm, an organic photoreceptor can be obtained that can produce high-quality images without interference patterns.

Conventionally, when anodizing the surface of a substrate made of aluminum or an aluminum alloy, alkali cleaning and acid cleaning have been performed as pretreatments. Of these treatments, alkaline cleaning is performed to ensure good film formation by etching the substrate surface to create a fresh surface before anodizing, while acid cleaning neutralizes the alkaline cleaning solution. It is something we do for the purpose of doing so. However, this etching process causes the surface shape of the substrate to change in a complex manner, making it virtually impossible to control the shape.

In the manufacturing method of this invention, this pretreatment is not performed, so
An anodic oxide film is formed without changing the surface shape of the substrate, which has been made to have an optimal roughness by mechanical treatment, and a reliable effect of preventing interference patterns can be obtained.

〔Example〕

FIG. 1 is a conceptual cross-sectional view of one embodiment of a conductive substrate according to the present invention.
Without alkaline and acid cleaning as pre-treatment,
It is provided with an anodic oxide film 2a formed under film-forming conditions that provide a flat surface.

Examples 1 to 4 The surface of the aluminum alloy substrate was cut to give Rmax of 0.6 μm, 0.8 μm, and 1.0 μm, respectively.
The surface was roughened to 4.0 μm, and an anodic oxide film was formed on the film under conditions such that the film surface was flat without performing alkaline cleaning or acid cleaning as a pretreatment. Photoreceptors of Examples 1 to 4 were prepared by sequentially coating and forming a charge generation layer and a charge transport layer.

Example 5 A photoreceptor of Example 5 was produced in the same manner as in Example 1, except that the surface of the aluminum alloy substrate was roughened by liquid honing instead of cutting.

Example 6 A photoconductor of Example 6 was produced in the same manner as in Example 1, except that the surface of the aluminum alloy substrate was roughened by sandblasting instead of cutting.

Comparative Examples 1 to 6 After carrying out alkali cleaning and acid cleaning as pretreatment on the substrates subjected to roughening processing corresponding to Examples 1 to 6, respectively, a charge generation layer and a charge generation layer were applied thereon in the same manner as in the examples. Photoreceptors of Comparative Examples 1 to 6 were prepared by sequentially coating and forming transport layers.

Comparative Example 7 FIG. 2 is a conceptual cross-sectional view of a conventional example of a conductive substrate,
An anodic oxide film 2b is formed on an aluminum alloy substrate 1 whose surface is mirror-finished under film-forming conditions such that the film surface becomes a rough surface 3b. A photoreceptor of Comparative Example 7 was produced in the same manner as in the Examples using this conventional substrate.

For the photoreceptors of Examples and Comparative Examples thus obtained, image evaluation was performed using a semiconductor laser beam printer. The results are shown in Table 1 in correspondence with the substrate treatment details of each photoreceptor.

As seen in Table 11, the photoreceptors of Comparative Examples 1 to 6 used substrates on which an anodic oxide film was formed after performing alkali cleaning and acid cleaning on any of the substrates subjected to mechanical roughening. However, in the case of the photoreceptors of Examples 1 to 6, which used substrates on which anodic oxide films were formed without performing alkaline cleaning or acid cleaning, no interference patterns were generated in images. It turns out that the treatment method is extremely effective. In addition, in the photoreceptor of Comparative Example 7 using a substrate according to the conventional technology, no interference pattern occurs in the image, but because the surface of the anodic oxide film on the surface of the substrate is rough, when a charge generation layer is formed on it, There was a problem in that coating unevenness occurred and a uniform and good charge generation layer could not be obtained.

〔Effect of the invention〕

According to this invention, the surface of the conductive substrate made of aluminum or aluminum alloy has a maximum height Rmax of 0.6
The surface is roughened within a range of 4.0 μm or more, and an anodic oxide film is formed on the surface without performing alkali cleaning or acid cleaning as a pretreatment, and a charge generation layer made of an organic material is formed on the surface. A photoreceptor is manufactured by sequentially coating and forming a charge transport layer.

By using a substrate treated as described above, no interference pattern will occur in the image. In addition, it is possible to form an anodized film on the substrate, giving top priority to the ability to prevent charge injection and the smoothness of the film surface. In this way, a high-quality image with a good charge injection blocking layer and charge generation layer and almost no black spots can be obtained.
This results in an organic electrophotographic photoreceptor that can produce images without interference patterns even when used in a printer that uses a light source with a wavelength in the range of 800 nT11.

[Brief explanation of drawings]

FIG. 1 is a conceptual sectional view of an embodiment of a conductive substrate according to the present invention, and FIG. 2 is a conceptual sectional view of a conventional example of a conductive substrate. l Aluminum alloy substrate, 2a, 2b anode first
Figure 2

Claims (1)

[Claims] 1) In a method for manufacturing an electrophotographic photoreceptor in which a charge generation layer made of an organic material and a charge transport layer made of an organic material are sequentially laminated on a conductive substrate made of aluminum or an aluminum alloy, the surface of the conductive substrate is maximum height R
The surface is roughened to a maximum of 0.6 μm or more and 4.0 μm or less, and the surface is anodized without alkali cleaning or acid cleaning as pretreatment, and then sealed to form an anodized film. 1. A method for producing an electrophotographic photoreceptor, which comprises forming a charge generating layer and a charge transporting layer thereon in order.