JPS6234182A - Method for restoring surface of photosensitive body - Google Patents

Abstract

PURPOSE:To prevent deterioration of the surface resistivity of a photosensitive body and to effectively inhibit image flow phenomenon by rubbing the amorphous silicon surface layer of the photosensitive body with a material made of a polyester resin. CONSTITUTION:The amorphous photosensitive body having the upper most layer made of amorphous silicon as a matrix has superior characteristics, but its surface adsorbs oxides and an active gas, such as ozone, produced in an electrostatic charging step and a transfer step, resulting in lowering the surface resistivity, and causing lateral flow phenomenon of an image. The brush, roller, and blade, or the like of a cleaning device are made of the polyester resin, and the surface of the photosensitive body is rubbed with them, thus permitting the active gas adsorbed at the surface to be removed, and the surface to be restored, consequently, deterioration of the surface resistivity to be prevented, and the lateral flow of the image to be effectively inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for surface recovery of an amorphous photosensitive material having an amorphous silicon-based layer as its outermost surface layer.

Conventional technology In recent years, amorphous silicon produced by glow discharge decomposition method or sputtering method has been developed.
The application of s5ilicon (hereinafter abbreviated as a-si) to photoreceptors has been attracting attention. This is because A-SI has better environmental pollution resistance, heat resistance, and
This is because it is even more excellent in abrasion resistance, photosensitivity characteristics, etc. Furthermore, due to the characteristics of the manufacturing method, various elements such as hydrogen, boron, carbon, nitrogen, oxygen, fluorine, phosphorus,
This is because chlorine, germanium, etc. can be easily added, and various performances corresponding to them can be obtained, such as improvements in dark resistance, charge retention ability, and sensitivity in the long wavelength region.

However, since the surface of the material based on a-si is originally very active, the photoreceptor made of a-si is subjected to conventional electrophotographic processes such as charging, image exposure, development, and so on.
When used in a process including transfer and cleaning, the photoreceptor adsorbs active gases such as nitrogen oxides and ozone generated during charging or transfer, resulting in a decrease in surface resistance. Naturally, in the conventional electrophotographic process, it is necessary to maintain the electrostatic latent image on the surface of the photoreceptor for a certain period of time, or if the surface resistance decreases, the retention of the latent image becomes insufficient and the surface A lateral flow of charges occurs along the line, resulting in image deletion during development.

As a method for preventing the above-mentioned image deletion phenomenon, many proposals have been made, including providing a protective layer on the surface of the photoreceptor. In such photoreceptors, other elements such as hydrogen, boron-carbon, nitrogen, oxygen, fluorine, etc. are added to the outermost layer in order to increase the surface resistance and reduce the adsorption of active gases (to prevent image blurring). Some have added other materials or coated the outermost layer with different materials.

Problems to be Solved by the Invention However, in the above-mentioned photoreceptor, if the above-mentioned elements are added to the outermost layer simply to increase the surface resistance, the residual potential increases,
Inconveniences such as a decrease in short wavelength sensitivity may occur.

Furthermore, the electrophotographic characteristics of the photoreceptor vary considerably depending on the content of elements contained in the outermost layer.

For example, when carbon is contained in the outermost layer of a-5i as a matrix, if the carbon content is small, image deletion occurs under high humidity conditions.

Even if the carbon content is large, there is a drawback that image deletion tends to occur under high humidity conditions after long-term use, and this also causes an increase in residual potential, a decrease in short wavelength sensitivity, and the like.

On the other hand, if a different material is coated on the surface of the photoreceptor,
Although surface hardness and abrasion resistance are increased and adsorption of active gas can be prevented, the characteristics of the photoreceptor itself are likely to be impaired. That is, a
When a photoreceptor having a layer containing -si as its outermost surface layer is coated with a different material, it improves environmental pollution resistance, heat resistance,
This makes it impossible to fully utilize the characteristics of a-si, which has excellent photosensitivity characteristics and the like.

Therefore, each method causes various inconveniences and cannot sufficiently prevent the image deletion phenomenon.

In view of the above-mentioned circumstances, an object of the present invention is to perform an electrophotographic process using a conventional method using an amorphous photosensitive material having an a-si matrix layer as the outermost layer. Surface recovery of the photoreceptor, which can effectively prevent the image deletion phenomenon of the photoreceptor without detracting from the excellent electrophotographic properties of A-SI even if elements are added or coated with a different material. The point is to provide a method.

Means for Solving the Problems The present invention provides charging, image exposure, development, and
The object of the present invention is to provide a method for restoring the surface of a photoreceptor, which is characterized in that the surface of the photoreceptor is rubbed with a material made of polyester resin during image formation in an electrophotographic process including transfer and cleaning.

To explain in more detail, the photoreceptor is charged, image exposed,
When used in the image forming process of electrophotography including development, transfer, and cleaning, active gases such as nitrogen oxides and ozone are generated during charging or transfer and are adsorbed to the surface of the photoreceptor, reducing surface resistance and causing image deletion. occurs. In the present invention, the surface of the photoreceptor on which active gas has been adsorbed is rubbed with a material made of polyester resin to restore the surface of the photoreceptor. This prevents the active gas from adsorbing and accumulating on the surface of the photoreceptor as copying continues, and the electrostatic latent image is always formed on a clean surface. Therefore, the image deletion phenomenon can be effectively prevented.

In the present invention, the photoreceptor can take any form as long as it is appropriately rubbed by the polyester resin material during repeated copying processes.

Hereinafter, typical embodiments will be described in detail. In the first embodiment, a material made of polyester resin is used for the cleaning device. During a cleaning step in a conventional electrophotographic process, it is necessary to rub the surface of the photoreceptor with a cleaning device including a brush, roller, blade, etc. in order to remove residual toner on the photoreceptor. In this case, the cleaning device such as the brush, roller, or blade is made of polyester resin, and by rubbing the surface of the photoreceptor with the device, the active gas adsorbed on the surface of the photoreceptor can be removed. - For example, a blade is made of polyester resin as a cleaning means and is brought into pressure contact with the surface of the photoreceptor. By doing this, the surface of the photoreceptor is rubbed by a blade made of polyester resin during the repeated copying process, so that the active gas adsorbed on the surface of the photoreceptor is removed, thereby preventing the phenomenon of image deletion.

In the second embodiment, a material made of polyester resin is used as the developer. During development in a conventional electrophotographic process, toner particles are attached to a photoreceptor in order to visualize the electrostatic latent image formed on the photoreceptor. In this case, by using toner particles made of polyurethane resin as a developer and rubbing the surface of the photoreceptor with the particles, the surface of the photoreceptor to which the active gas has been adsorbed can be recovered and the image deletion phenomenon can be effectively prevented. . Furthermore, by using polyester resin as the toner, it is possible to effectively prevent toner from fusing on the surface of the photoreceptor.

Effects of the Invention As is clear from the above description, in the present invention, since a material made of polyester resin is rubbed on the surface of the photoreceptor, adsorption and accumulation of active gas on the surface of the photoreceptor can be avoided. As a result, a decrease in surface resistance and an image blur phenomenon can be effectively prevented.

Furthermore, in the present invention, in an electrophotographic process using a conventional method,
The cleaning means and the developer can be simply made of polyester resin, so it is extremely easy to carry out.

Examples of the present invention will be described below.

Example 1 Example of using a polyester resin for a blade> A film with a thickness of approximately 30 μm was placed on an A6 substrate using a known method.
An amorphous photosensitive material containing silicon was prepared by sequentially laminating a layer containing -si as a matrix and a layer containing a-si as a matrix and having a thickness of about 04 μm.

The photoreceptor thus obtained was sold to Minolta Camera Co., Ltd.
450Z copying machine, a blade made of polyester resin was pressed against the photoconductor as a cleaning device, and a running test was conducted. fBl was performed. That is, when cleaning the photoreceptor in the image forming process including charging, image exposure, development, transfer, and cleaning, a blade made of polyester resin and a blade made of polyurethane resin were used in the running test (Al, (Bl The above blade made of polyester resin and the blade made of polyurethane resin were used for image evaluation.
The blade was replaced every time 00 copies were made, so that a clean blade was always rubbed against the photoreceptor.

The results of the above running test (Al, (Bl) were repeated alternately are shown in Table 1. However, the cumulative total was 9000 sheets, 6
When the number of copies was 9,000, continuous copying was then performed for 51,000 copies.

Margin Table 1 (○: Good quality × Partial image blurring × × 2 Self-image blurring) As is clear from Table 1, there is more image blurring with the blade made of polyester resin than with the blade made of polyurethane resin. Furthermore, it can be seen that when the blade is made of polyester resin, it also has the effect of recovering from the image deletion caused by the running test (B).

In addition, because the surface hardness of A-SI is extremely high, even if a blade made of highly hard polyester resin is used, the surface of the photoreceptor will not be damaged in any way (even after 120,000 copies have been made continuously). I was able to obtain clear images with no image blurring.

Example 2 <Example using polyester resin in toner>
An amorphous photosensitive material similar to that used in Example 1 was set in an EP650Z copying machine manufactured by Minolta Camera Co., Ltd.
A running test (FC+) using a toner made of polyester resin and a running test (D+) using a toner made of styrene-acrylic resin were conducted.
During the image creation process, which includes image exposure, development, transfer, and cleaning,
When developing the electrostatic latent image formed on the photoreceptor with a magnetic brush, the above running test (
C1, p) was performed to perform image evaluation.

Table 2 shows the results of alternately repeating the running tests FC+ and FD+.

As is clear from Margin Table 2 below, the toner using polyester resin is less likely to cause image bleeding than the toner using styrene-acrylic resin.
), it can be seen that the state where image deletion has occurred can be recovered.

As a result of this test, it was possible to obtain clear images without image blurring even after continuous copying of 1 million copies.

Claims (1)

[Claims] 1. During the image formation process of the electrophotographic process, which includes charging, image exposure, development, transfer, and cleaning, performed on an amorphous photoreceptor having an amorphous silicon matrix layer as its surface layer, the surface of the photoreceptor is , a method for restoring the surface of a photoreceptor, characterized by rubbing it with a material made of polyester resin.