JPH0363743B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing an electrophotographic photoreceptor, and more particularly to a method for manufacturing an electrophotographic photoreceptor with improved cleaning properties and durability for repeated use. polyvinylcarbazole, oxadiazole,
Organic photoconductive substances such as phthalocyanine contain selenium,
Compared to inorganic photoconductive materials such as cadmium sulfide, it has advantages such as non-pollution and high productivity, and has been put into practical use to some extent. However, since the organic photoconductive substance is exposed on the surface of a photoreceptor using an organic photoconductive substance, it is easily deteriorated physically and chemically. In other words, electrophotographic photoreceptors undergo processes such as charging and phenomena caused by corona discharge, transfer to paper, and cleaning treatment, but there are also deterioration factors such as oxidation of the surface due to corona discharge and rubbing with paper due to transfer. . Furthermore, if the cleaning process is a blade cleaning method in which a rubber blade is pressed against the toner to scrape off the toner, if the surface of the photoreceptor is weak, scratches are likely to occur. Therefore, the surface of the photoreceptor must be resistant to the above-mentioned deterioration factors. but,
Photoreceptors using organic photoconductive materials have been difficult to obtain, and are particularly susceptible to deterioration due to corona discharge and scratches. One way to solve this problem and improve durability is to
Another method is to add a protective layer to the surface. That is,
As shown in FIG. 1, this is a method in which a photosensitive layer 2 is formed on a substrate 1, and a protective layer 3 is provided on the surface of the photosensitive layer 2. The protective layer is a resin layer provided on the surface of the photosensitive layer, which does not easily deteriorate. Since this resin layer does not contain a photoconductive substance, it has durability against deterioration factors. However, in the method using a protective layer, charges are accumulated in the protective layer, resulting in deterioration of characteristics such as a decrease in sensitivity and an increase in residual potential, and causes background fog in copied images. SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned disadvantages and to provide an electrophotographic photoreceptor with improved durability without deteriorating electrophotographic properties. The present inventor has recognized that it is effective to form a protective layer of silicone resin on the surface of a photoreceptor in order to improve the durability of the photoreceptor, and has developed a method for creating a protective layer with less charge accumulation. The present invention was completed by studying the following. That is, the present invention provides a method for manufacturing an electrophotographic photoreceptor having a photosensitive layer having a charge transport layer on a charge generation layer, in which a dimethylpolysiloxane structure is formed on the charge transport layer using a solvent that dissolves the charge transport layer. This is a method for manufacturing an electrophotographic photoreceptor, characterized by spray coating a silicone resin. Silicone resin is a resin containing silicon, and its basic skeleton is dimethylpolysiloxane, but it is made into a resin by partially disposing reactive functional groups and crosslinking it. The lacquer type forms a film simply by reacting all the functional groups and drying the solvent.
There is a curing type in which functional groups are left behind and further reacted, but any of them may be used in the present invention. Silicone resin has weather resistance, heat resistance, chemical resistance,
It has excellent wear resistance, water repellency, high insulation properties,
It has characteristics such as low friction. Silicone resin has a high electrical resistance, so if it is coated as is to form a protective layer, it will remain charged, creating a residual potential. In order to solve this problem, we used a silicone resin solvent that also dissolves the photosensitive layer, and when forming the silicone resin layer, the silicone resin solvent attacked the surface of the photosensitive layer. The interface between the silicone resins was made compatible so that the components of the photosensitive layer were dissolved into the silicone resin. The situation is shown in Figure 2. 4 in the figure shows the protective layer of the present invention in which the components of the photosensitive layer are diffused;
This layer is composed of a silicone resin layer, and it is thought that the components of the photosensitive layer diffuse from the lower interface with a concentration gradient. By doing so, the charge charged on the silicone resin layer becomes easier to move. In order to form the protective layer in this manner, it is necessary to prevent the photosensitive layer from being eluted and to prevent the silicone resin and the photosensitive layer from completely mixing when forming the silicone resin layer. The most suitable method for forming such a protective layer is spray coating, which is a feature of the present invention. When a silicone resin solution is sprayed onto the photosensitive layer by spray coating, the silicone resin and the photosensitive layer become compatible at the interface due to the silicone resin's solvent.On the other hand, in spray coating, the solvent dries quickly. The surface of the silicone resin layer was quickly dried to form a film, and the photosensitive layer did not elute. To explain the electrophotographic photoreceptor in the present invention in more detail, first, the substrate is made of metal such as aluminum, brass, or stainless steel, or polyethylene terephthalate, polybutylene terephthalate,
Polymer materials such as phenolic resin, polypropylene, nylon, and polystyrene, and materials such as hard paper are molded into a cylindrical shape or used as a film or foil. In the case of an insulator, it is necessary to conduct conductive treatment, which can be done by impregnating it with a conductive substance, laminating metal foil, or vapor depositing metal. In order to increase the sensitivity of the photosensitive layer, it is effective to use a functionally separated photosensitive layer in which a charge generation layer and a charge transport layer are separated. The charge generation layer is made of azo pigments such as Sudan Red, Diane Blue, and Jenas Green B; quinone pigments such as Algol Yellow, Pyrene Quinone, and Indanthrene Brilliant Violet RRP;
Indigo pigments such as quinocyanine pigments, perylene pigments, indigo and thioindigo, bisbenzimidazole pigments such as India First Orange Toner, phthalocyanine pigments such as copper phthalocyanine, quinacridone pigments, and charge generating substances such as pyrylium dyes, polyester, polystyrene, It is formed by dispersing it in a fixing agent resin such as polyvinyl chloride, polyvinyl acetate, acrylic, polyvinyl butyral, polyvinylpyrrolidone, methylcellulose, hydroxypropylmethylcellulose, and cellulose esters. Further, it can also be formed by vapor deposition or the like. The thickness of the charge generation layer is 0.05~
It is about 0.2μ. In addition, the charge transport layer may contain polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, coronene, indole, carbazole, etc. in the main chain or side chain.
Oxazole, isoxazole, thiazole,
imidazole, pyrazole, oxadiazole,
It is formed by dissolving a hole-transporting substance such as a compound having a nitrogen-containing cyclic compound such as pyrazoline, thiadiazole, or triazole, or a hydrazone compound in a resin that has film-forming properties. This is because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself. Examples of such resins include polycarbonate, polyarylate, polystyrene, polymethacrylate esters, styrene-methyl methacrylate copolymer, polyester, styrene-acrylonitrile copolymer, polysulfone, and the like. The thickness of the charge transport layer is approximately 5 to 20 microns. A silicone resin is spray-coated onto the charge transport layer, and its thickness is preferably about 1 to 5 microns. If it is too thin, it will mix with the charge transport layer, making the protective layer ineffective, and if it is too thick, residual charges will appear. The solvent for the silicone resin dissolves the film-forming resin of the charge transport layer, and the faster the drying speed, the better. For example, triene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. are optionally used in mixed threads. The electrophotographic photoreceptor produced by the method of the present invention is
Since the surface is covered with silicone resin, it has increased durability against corona discharge deterioration, cleaning scratches, abrasion scratches, etc., and has been able to extend the life of the photoreceptor. Characteristically, the residual potential was small and there was no decrease in sensitivity. Example 1 An aluminum cylinder of 80φ×300mm was used as a base. Separately, 10 parts (by weight, same hereinafter) of copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries) was added to 60 parts of methanol, and the mixture was heated and dissolved at 50°C. After cooling, 30 parts of toluene was added. This liquid was applied to the above substrate by dipping and dried with hot air at 100°C for 10 minutes to form a 2μ thick undercoat layer. Next, add 10 parts of the disazo pigment with the following structural formula. Cellulose acetate butyrate resin (product name: CAB-381;
(manufactured by Eastman Chemical) and 60 parts of cyclohexanone were dispersed for 20 hours using a sand mill device using 1φ glass beads. Add 100 parts of methyl ethyl ketone to this dispersion, dip coat it onto the undercoat layer, heat dry at 100°C for 10 minutes, and apply 0.08 g/
The amount of charge generated was equal to the coating amount of ^m2 . next, 10 parts of a hydrazone compound represented by the structural formula: acrylonitrile-styrene copolymer resin (trade name:
SAN-C (manufactured by Mitsubishi Monsanto Chemicals) was dissolved in 70 parts of monochlorobenzene, and this solution was applied onto the charge generation layer. Heat drying was performed at 100° C. for 40 minutes to form a charge transport layer with a thickness of 6 μm. On top of this charge transport layer, silicone resin (product name: SR2410, manufactured by Toray Silicone) is applied with a solid content of 10%.
Dilute with toluene so that it is, and use a Binks spray gun at an air pressure of 1.5 Kg/cm ² , a distance between the gun and the substrate of 3 cm, and a coating volume of 8 ml/min.While rotating the substrate, move the gun in the longitudinal direction of the substrate. I sprayed it while letting it flow. Thereafter, it was thoroughly dried with warm air at 40°C, and further heated at 100°C for 1 hour. In this way
A protective layer with a thickness of 2μ was formed. This surface had good water repellency and was resistant to dust. The electrophotographic photoreceptor manufactured in this way was subjected to -5.5KV corona charging, image exposure, dry toner phenomenon, toner transfer to plain paper, urethane rubber blade (hardness 70°, pressure 10gw/cm, We evaluated the electrophotographic characteristics of an electrophotographic copying machine that has a process of cleaning at an angle of 20° and repeated use.The evaluation was based on initial potential (V ₀ ), sensitivity (E ₀ ), and Potential (V ₂₀₀₀ and V ₅₀₀₀ ) and sensitivity (E ₂₀₀₀ and E ₅₀₀₀ ) after repeated use of
measurements, and looked at the image quality of the copied images. Sensitivity is the amount of exposure (lux) required to attenuate the potential to 1/10 during dark decay for 2 seconds after corona charging.
The evaluation was made by measuring the time (seconds). These results are shown in Table 1.

[Table] Even when images were taken in an atmosphere of 30°C and 90% RH using the photoreceptor after 5000 uses, the image quality remained good. For comparison, a similar evaluation was performed on a photoreceptor without a silicone resin protective layer formed on the charge transport layer. The results are shown in Table 2.

[Table] When viewing images using a photoconductor that had been used 5,000 times in an atmosphere of 30° and 90% RH, some parts of the text appeared faded. In other words, it was found that the presence of the silicone resin protective film improved the durability. Furthermore, since toluene, which is a solvent for silicone resin, dissolves the charge transport layer, it has been difficult to apply it by any method other than spray coating according to the present invention. Example 2 A completely similar photoreceptor could be produced by using another silicone resin (trade name: SR2411, manufactured by Toray Silicone) in place of the silicone resin used in Example 1. Example 3 Instead of the silicone resin used in Example 1,
Epoxy modified silicone resin (product name:
A similar photoreceptor was also obtained using ES1001N (manufactured by Shin-Etsu Chemical Co., Ltd.). However, in this case, a special curing agent was added and the heating temperature was set for 2 hours.

[Brief explanation of drawings]

Figures 1 and 2 show an example of an electrophotographic photoreceptor, in which 1 is a substrate, 2 is a photosensitive layer, 3 is a protective layer provided on the photosensitive layer, and 4 is a layer in which the components of the photosensitive layer are diffused. This figure shows the protective layer of the present invention.

Claims (1)

[Claims] 1. In a method for manufacturing an electrophotographic photoreceptor having a photosensitive layer having a charge transport layer on the charge generation layer, a silicone resin having a dimethylpolysiloxane structure is applied on the charge transport layer using a solvent that dissolves the charge transport layer. A method for producing an electrophotographic photoreceptor, the method comprising spray coating.