JPS59152444A - Photosensitive screen body - Google Patents

Abstract

PURPOSE:To improve the primary potential characteristics and retentivity of a photosensitive screen body for an electrophotographic system using a screen process by making the central part of the substrate of a screen mesh thinner than the peripheral part. CONSTITUTION:The central part of the substrate 1 of a screen mesh for manufacturing a photosensitive screen body for an electrophotographic system using a screen process is made thinner than the peripheral part by shaving, and a PC layer 2 and an InS layer 3 are coated on the substrate 1 to obtain the desired photosensitive screen body. Since the screen mesh 1 is concaved, each of the layers 2, 3 can be coated to a large thickness, and sticking to the side of the mesh 1 is hardly caused. Accordingly, the potential of a primary latent image is stabilized, the area of openings is increased to improve the efficiency of transfer of a secondary latent image, and many copies can be obtd. from one latent image without reducing the image density.

Description

[Detailed description of the invention] This invention relates to a screen photoreceptor used in the true method.

A screen photoreceptor has the same structure in principle as a normal electrophotographic photoreceptor, but differs in that it has a large number of fine apertures. The most common method of using a screen photoreceptor is to form an electrostatic image on the screen photoreceptor, and this electrostatic image is used as a primary electrostatic image to form a secondary electrostatic image on a recording medium. . The formed secondary electrostatic image is visualized. For example, in a screen photoreceptor whose basic structure is a conductive layer and a photoconductive layer formed thereon, for example,
A 91st electrostatic image is formed by a process of charging and then imagewise exposure. In addition, in the case of a screen photoreceptor further provided with an insulating layer on the photoconductive layer, for example, primary voltage application, image exposure, simultaneous deposition with image exposure, secondary voltage application after image exposure, and whole surface exposure A primary electrostatic image is formed by the process of applying a primary voltage and simultaneous exposure, applying a secondary voltage, and exposing the entire surface (in this case, the application of a secondary voltage refers to the process of applying a primary voltage to the image). (This is a process of removing static electricity or charging it to the opposite polarity after removing the static charge.)

The above-mentioned method for forming a primary electrostatic image is just one example, for example, Japanese Patent Publication No. 46-39318,
-5971 publication, Japanese Patent Publication No. 48-5063.

A primary electrostatic image is also formed by many processes disclosed in Japanese Patent Application Laid-open No. 48-59840 and Japanese Patent Application Laid-open No. 51-341. A screen photoreceptor on which a primary electrostatic image is formed is placed facing the recording medium, and by applying a voltage through the screen photoreceptor, a secondary electrostatic image is formed on the surface of the recording medium. It is formed. The ion flow generated when voltage is applied is caused by the electric field caused by the primary electrostatic image formed on the screen photoreceptor, and the opening of the screen photoreceptor is
Then selectively passes through the electrostatic image to reach the recording medium surface,
A secondary electrostatic image is formed there. This secondary electrostatic image is developed and fixed by a normal developing method in electrophotography. The secondary electrostatic image may be electrostatically transferred to another recording medium and then developed, or the developed secondary electrostatic image may be transferred to another recording medium.

The copying method using a screen photoreceptor has several features. For example, screen photoreceptors do not undergo direct development processing, so the photoreceptor has good durability;
Further, in the case of a screen photoreceptor having an insulating layer on its surface, a primary electrostatic image formed once can be repeatedly used to make a large number of copies. This is especially advantageous in terms of high speed copying.

Examples of the conductive material constituting the screen photoreceptor include metals such as stainless steel, copper, aluminum, and tin, and metal oxides such as polyvinyl pyrrolidone, In, chromium, and tin. These materials are used in various forms to form the conductive layer. For example, in the case of metal, metal powder dispersed in a resin solution can be filled.

Still, in the case of conductive resin, it can be filled with its solution.

Examples of photoconductive materials include S e Ser Pb
ol and S r Se y Te p As r Sb
Alloys and intermetallic compounds with p pb etc., ZnOr
Inorganic photoconductive materials such as CdS e TiO2z, organic photoconductive materials such as polyvinylcarbazole, anthracene, and phthalocyanine, and those obtained by color sensitization or Lewis acid sensitization of these organic and inorganic photoconductive materials, as well as insulating binders and A mixture of can be used. Note that as the insulating binder, inorganic substances such as organic insulators and glass, which are used for insulating materials described below, can be used.

Although the thickness of the photoconductive layer formed by the above-mentioned method depends on the type and characteristics of the photoconductive material used, it is generally appropriate that the maximum thickness is about 10 to 80 .mu.m. Next, the insulating material must have high resistance, have charge retention properties, be transparent to irradiation in the irradiation process, and does not necessarily need to have excellent wear resistance. Examples of materials that meet the above requirements include acrylic resin, vinyl chloride resin, silicone resin, phenol resin, fluororesin, and styrene resin.

Vinyl acetate resin.

Resins that are dissolved in solvents such as epoxy resins, urethane resins, and phenolic resins.

Amino other layer, fluorocarbon resin, vinyl acetate h6s photocurable unsaturated polyester resin, acrylic pillow! j+-p alkyd resin.

Thermosetting resins such as resins that are liquid before curing, but become solid after curing by hardening agent, heat, light, etc.
Examples include photocurable resins. 〇In the case of resins that do not contain bath agents, "drying" becomes "curing." The above classification of resins is general, and curable resins may be used together with solvent-based resins, or vice versa. The insulating layer is set to have a thickness of 10 μm at its maximum thickness.

However, the size of the mesh of the conductive material constituting the screen photoreceptor is limited to 150 to 500 meshes due to the usable range, and the appropriate width of each line is 10 to 80μ, and the width of the opening is 25 to 500. It is 150μ, so the aperture ratio is in the range of 25 to 80%. And, for example, do it with 400 meshes.

When the line width is approximately 20μ, the width of the opening portion is approximately 45μ, and the aperture ratio is approximately 50%. In this case, from the viewpoint of mechanical strength and manufacturing technology, the thickness of the mesh is approximately 1
5μ is appropriate. A photoconductive layer, for example a Cd5-binder system, and an insulating layer of silicone resin are provided on this mesh.

In view of the conditions of the screen process, the required thickness of the photoconductive layer is 15 to 20 .mu.m, and the thickness of the insulating layer is 2 to 3 .mu.m. However, if the cross-sectional shape of the mesh is a straight rectangle as shown in Figure 1, it is difficult to apply the CdS layer thickly when applying it by spraying, and if you apply too much CdS, it will stick to the sides and back of the mesh. The present invention solves the problem that the 920 layer, which has a small aperture ratio and line width, cannot be coated thickly due to the high mesh size (400 to 500 mesh), and also improves the PC This also makes it possible to prevent the InS layer from adhering to the side surfaces of the mesh and deteriorating its properties.

That is, in the present invention (-A), in a screen photoreceptor used in an X-ray photography method using a screen process, the cross-sectional shape of the base of the screen mesh is such that the central part is 91° larger than the peripheral part.
This is a screen photoreceptor characterized by a plate thickness that is 0% to 50% smaller.

The present invention will be explained in detail below using the drawings.

Figure 1 is a diagram showing a cross section of a conventional screen mesh, Figure 2 is a diagram showing a cross section of an embodiment of the present invention in which the upper part of the mesh has been cut into a round shape, and Figure 3 is a diagram showing a cross section of a mesh in another embodiment. Figure 4 shows a cross section of a conventional screen mesh coated with a PC layer and an InS layer, and Figure 5 shows a mesh with a rounded upper surface. FIG. 2 is a cross-sectional view of an embodiment of the present invention coated with a PC layer and an InS layer.

Generally, when the screen mesh is 250 to 400 meshes, the line width C, is 20 to 25μ, and the plate thickness d, is 1'5~
It is 20μ. The length of the opening 81 at this time is 45 to 7
At 0μ, the 910 area ratio is 40 to 50%. When a PC layer and a 20 μm InS layer are applied to this mesh using a 3 μm spray method, the PC layer and InS layer will also adhere to the sides, so there will be some damage.
The length of part a is narrower and the anus is 25μ.9
The 10 area ratio will also be about 15 inches. If the PC layer and the InS layer are coated with a large opening area ratio, the thickness a of the PC layer will become small.

Therefore, in the present invention, as shown in FIG. 2, the central part of the screen mesh is cut into a round shape, and a layer of PC/e of 20 μm and a layer of In8 of 3 μm is similarly applied thereto.

In this case, since the center of the mesh is concave, the PC layer and the In3 layer do not adhere to the sides of the mesh.

Therefore, the length bi of the opening is wide (30 to 35μ, and the opening area ratio is 20 to 28 inches.At this time, the thickness a' of the PC layer is the same as the thickness a of the PC layer of the conventional mesh. However, the indentation f2 in the center prevents it from protruding to the sides.The amount of indentation f2 is 2 to 7μ in this case.The thickness of the center is preferably lθ to 50cm, which is the thickness of the edges. If it is too much, it will not be effective, and if it is too much, the strength of the mesh will deteriorate, so it should be within this range.

Although the screen having a circular depression on the top surface of the mesh as in the above embodiment is effective in coating the PC layer and the InS layer,
The mesh may not be particularly roundly recessed, but may be recessed linearly as shown in FIG. 3, and even if the center is not recessed, both ends may be raised as shown in FIG. 6.

As explained above, by recessing the center of the top surface of the screen mesh, the 920 layer and the InS layer can be applied thickly, and there is less adhesion on the sides, which has a remarkable effect on improving the electrophotographic properties of the screen. The Qin Dynasty. - Since the 1ppc layer is thicker, the potential of the primary latent image can be stably obtained, and because the aperture area ratio is large, the transfer efficiency of the secondary latent image is poor.As a result, the image density with the same latent image is reduced. A large number of copies can be made without degrading the performance, that is,
Retention characteristics are also improved.

The following sample was created as an example.

The pc77 and ins layers were applied by a spray method.

The electrical potential characteristics, strength, and durability of the above Lannor were measured.

◎: Particularly good, Q: Good, △: Slightly poor. ×: From the results above poor, it was found that by making the center of the substrate thinner by 10% to 50 inches, good results could be obtained and the object of the present invention could be achieved.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional screen mesh, Fig. 2 is a cross-sectional view of an embodiment of the present invention in which the upper surface of the mesh is roundly recessed, and Fig. 3 is a diagram showing the upper surface of another embodiment. Figure 4 shows a cross section of a conventional mesh with a PC layer and InS layer applied to it. Figure 5 shows an embodiment of the present invention with a rounded top surface. A diagram showing a cross section when a PC layer and an InS layer are applied to a recessed mesh, and FIG. 6 is a diagram showing a cross section of another embodiment of the present invention in which both ends of the mesh are raised. 1"°゛Base mesh) 2...26 layers, 3...In
S layer. Fig. 1 Two wings b" and Fig. 6] Z tuyer mouth

Claims (1)

[Claims] A screen photoreceptor used in electrophotography using a screen process, wherein the cross-sectional shape of the screen substrate is 10 to 50% thinner in the center than in the peripheral area.