JPS62204265A - Amorphous silicon photosensitive body - Google Patents

Abstract

PURPOSE:To improve the moisture resistance of an amorphous silicon photosensitive body and to considerably prolong the service life by specifying the maximum height of the surface roughness of the photosensitive body. CONSTITUTION:An amorphous silicon photoconductive layer is formed on the surface of a support to obtain an amorphous silicon photosensitive body. At this time, the photoconductive layer is formed so that the maximum height of the surface roughness of the layer is restricted to <=300Angstrom . By the restriction, the surface area is reduced, so the exposed defects are reduced and the moisture resistance is extremely improved. The miximum height is preferably restricted to <=100Angstrom so as to provide high resolution and durability. In case of <=50Angstrom maximum height, the removal of a toner is facilitated and the printing resistance of the photosensitive body can be extremely improved.

Description

Detailed Description of the Invention A. Field of Industrial Application This invention relates to electrophotographic photoreceptors used in copying machines, printers, etc., particularly photoconductive amorphous silicon (hereinafter referred to as a).
This relates to a photoreceptor (referred to as Si).

Prior Art Electrophotographic photoreceptors are used by attaching a thin film to a flat or cylindrical metal plate, or by forming a photoreceptor coating on the surface of a mirror-finished support by vapor deposition or other methods. A static electricity image is obtained by trapping static electricity on the surface, transferring an image of the subject onto the surface, creating an image with the same static electricity as the image using the photoconductivity of the photoreceptor, and attaching toner to it. It is used to transfer and print the same image on paper.

Conventionally, 8e and 5e-Te have been used as electrophotographic photoreceptors.

5e-As Se-based alloy, ZnO, Cd 8 compound.

Alternatively, organic photoreceptors such as PVK and phthalocyanine are used. However, the conventional photoreceptors have problems in terms of environmental pollution, thermal stability, mechanical strength, etc.

Amorphous silicon (
A photoreceptor using a-8i (hereinafter referred to as a-8i) has been proposed, and active research and development is underway. , has been discovered to be extremely excellent as a photoreceptor.

C1 Problems to be Solved by the Invention However, when the A-8i is actually incorporated into a copying machine or printer and used for a long period of time, it has the drawback of causing phenomena such as blurred images and white spots, making it practically unusable. won.

This is because if the a8+ film is left in the atmosphere for a long time, especially under high humidity, the electrical resistance of the surface will decrease and the photoconductive properties will become unstable. Although defects (dangling bonds) are relatively compensated for inside the layer, defects (dangling bonds) are exposed on the surface of the film, and ions and molecules in the atmosphere can easily be adsorbed in that area. This is thought to be because the electrical resistance in the surface direction changes.

21 Means for Solving Problems The present invention provides an amorphous silicon photoreceptor having an amorphous silicon photoconductive layer on the surface of the support, in which the maximum height of the surface roughness of the photoconductive layer is set to 300'A or less. This is an amorphous silicon photoreceptor characterized by being formed as follows.

The present inventors have discovered that the deterioration of the characteristics of the photoconductive layer of the a-8i photosensitive photosensitive layer due to humidity, etc. is closely related to the surface roughness of the surface of the photoconductive layer, and the present invention was made based on this finding.

Generally, when an A-8i photoconductive layer is formed on the surface of a support by glow discharge under normal conditions, the maximum height of the surface roughness is approximately x
Something of the order of oooX is obtained. As a result of research, it was found that a surface with this level of surface roughness has a large surface area, and therefore many of the above-mentioned fine defects are exposed on the surface and the characteristics deteriorate in a high humidity atmosphere. However, if the maximum height of surface roughness is 3
When it is less than 00^, the surface area is reduced, and therefore fewer defects are exposed, and the moisture resistance is greatly improved.

To make the maximum height of surface roughness 300X or less (a) When forming a film by glow discharge, adjust the substrate (support surface) temperature, reaction pressure, gas flow rate, RF (radio frequency current) power, etc. Tightly control. These film forming conditions are arbitrarily determined depending on the shape and size of the manufacturing equipment and the characteristics required for the product, but according to the results of experiments, as shown in Table 1.

It is better to set the substrate temperature to 200° C. or higher, which is higher than usual, and to set the RF power slightly higher than before.

(Etching is performed after forming the BL film.

Etching is preferably wet etching using a HF-HNO3 solution, and a surface roughness of 100 to 200 A can be obtained by this method.

(c) Mechanical surface polishing is performed after film formation.

By appropriately selecting the abrasive material, polishing liquid, and polishing conditions, a desired surface roughness can be obtained, and under the best conditions, a mirror surface with a roughness of 10 to 20X can be obtained.

In the present invention, the maximum height of surface roughness is usually aooi
Requires: However, in order to obtain even higher resolution and durability, it is preferable that the number is 1001 or less. Particularly, when it is 50X or less, in addition to high resolution, toner removal becomes easy and printing durability of the photoreceptor can be greatly improved.

Although the above description has been made with respect to a photoreceptor made of a-Si alone, the same effect can be obtained with a structure in which the surface of a-Si is coated with a thin protective film such as a Si compound, and the composition of the structure 1 can be selected arbitrarily. As long as it is possible, a-
8iKGe may be added to form a-8iGe to provide long wavelength sensitivity.

E. Using stainless steel (S, US) as an example support, one surface was polished to a mirror finish and a glow discharge method was applied to the surface.As shown in Figure 1, the support had a Ni electrode layer and an a-8iN barrier layer. , a-si
A Si photoconductive layer (electrophotographic photoreceptor) with a total thickness of 3 μm including a photoconductive layer + aStN surface layer was made.
A photoreceptor sample was prepared with surface treatment according to the present invention.

Then, a photoreceptor sample with the same cross section made under conventional film forming conditions without surface treatment and the photoreceptor sample were mounted on a copying machine, and the copying machine was left in a constant temperature bath at 35°C and 85% humidity overnight. A copying test was conducted and the initial image and the image after being left unused were compared.

The results were as shown in Table 1.

C F2 In the table, ○, ◎, and × indicate the following results.

○: Even after copying 100,000 times (printing durability) after being left unused, there are no white spots similar to the initial image, and an image with good resolution is obtained. ◎: Even after copying 200,000 times (printing durability) after storage When an image with very good resolution is obtained without any white areas similar to the initial image. ×: The initial image is good, but after being left alone, there are white areas and an image with poor resolution is obtained. Compared to the conventional sample 1, if the maximum height of the surface roughness of the a-8i photoreceptor is set to 300X or less as in the product of the present invention, the resolution of the photoreceptor is improved and the printing durability is greatly improved. I understand.

It should be noted that similar effects were obtained not only with the S TJ S used in the above-mentioned example as a support but also with other commonly used supports, as well as with a thin film or drum type support having a photoreceptor on its surface.

Effects of the Invention As explained in detail above, in the a-8i photoreceptor of the present invention, the maximum height of the surface roughness is set to 300X or less, so the surface area of the photoreceptor surface is reduced. Since adsorption of impurities such as moisture is reduced, moisture resistance is greatly improved, and the life of the photoreceptor is greatly extended. Furthermore, since the surface is smooth and has a small surface roughness and is a precise mirror surface, resolution is improved and toner adhesion (desorption) properties, that is, toner filming and toner cleaning properties are improved, resulting in better image resolution. This has great effects such as improved printing durability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a photoreceptor layer according to an embodiment of the present invention. (1)... a-8i photoconductive layer, (2)... support. (3)--Ni electrode, (4)-a-8iN barrier layer, (5)-a-8iN surface layer, Agent: Patent attorney 1) Rio Naka Figure 1

Claims (1)

[Claims] 1. In an amorphous silicon photoreceptor having an amorphous silicon photoconductive layer on the surface of the support, the maximum height of the surface roughness of the amorphous silicon photoconductive layer is 300 Å.
The amorphous silicon photoreceptor 2 is characterized in that it is formed as follows, and the amorphous silicon according to claim 1 is characterized in that the maximum height of the surface roughness of the photoconductive layer is 100 Å or less. Photoreceptor 3: an amorphous silicon photoreceptor according to claim 1, characterized in that the maximum height of the surface roughness of the photoconductive layer is 50 Å or less