JPS5983168A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To prevent attachment of a substance attached to the surface of a photoreceptor damaging and deteriorating it and to enhance surface characteristics of the photoreceptor by treating its surface with a surface treating agent. CONSTITUTION:Surface treatment is carried out by applying a surface treating agent to the surface of the photoreceptor by a proper means, and removing an excess of the agent so as not to leave it on the surface. A surface treating agent is used having chemical stability, high electric resistance, water repellency, and lubricity. In the case of using a silicone grease, deterioration of image quality can be prevented for a long term by applying a silicone grease incorporating ultrafine powder of SiO2 or Si3N4. It is presumably due to the fact that the silicone grease has good compatibility with a silicon compd., and a state of strong combination is ensured even on the surface of the photoreceptor, and the ultrafine powder mediates their combination and maintains a stable state for a long term.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor whose life and performance stability are increased by improving surface characteristics.

Generally, electrophotographic photoreceptors on which electrostatic images are formed are used in electrophotographic copying machines, printers, and the like. The structure of this photoreceptor is such that selenium (S@), zinc oxide (ZnO) *organic semiconductor (O
PG), amorphous silicon (a-8t), etc., or a photosensitive layer made of cadmium sulfide (Cd8) is formed on the substrate as described above, and further Photoreceptors are known that include an insulating layer made of Mylar or the like. In the former photoreceptor, the surface of the photosensitive layer is exposed, and sufficient care must be taken when storing it. In addition, when used for a certain period of time, various stimuli inside the copying machine (corona discharge, adhesion of products caused by corona discharge, stains caused by toner, friction caused by blades, etc.) may occur.
This tends to cause changes in the surface condition and deterioration of the photosensitive layer. Therefore, when the photosensitive layer is made of selenium, for example, maintenance is required such as polishing the surface with magnesium oxide or cerium oxide to remove dirt and expose a clean surface. On the other hand, since the surface of the latter type of photoreceptor is covered with an organic insulator, it can be handled relatively roughly, and the surface can be cleaned by rubbing it with a suitable woven cloth. It is small and has a strong affinity with toner containing organic components, and is said to have a rather short life span of the photoreceptor.

The influence of corona and discharge on the photoreceptor generates ions, ozone, and nitrogen oxides (NOx) in addition to corona discharge current, which may cause chemical damage to the surface of the photoreceptor. In order to solve this problem, a patent application filed in 1983 by the same applicant as the present application
No. 27519 discloses that an inorganic a-
A photoreceptor is taught in which a 8IN film is formed as a protective film. This photoreceptor has a clear advantage over conventional ones, mainly by improving the surface of the photosensitive layer against corona discharge during long-term continuous use. It has been found that when present, complex compounds are formed with active species such as ions, ozone, and NOx, which adhere to the surface of the photoreceptor and not only affect images but also damage and deteriorate the photoreceptor. Although the substances attached to these substances are not clear,
These include nitrogen compounds such as ammonium aniline, nitrogen oxides such as nitric acid and nitrous acid, and organic compounds such as carboxyl and aldehyde, and vary depending on the conditions at the time and cannot be particularly limited. Although these deposits are chemically unstable, many of them are soluble, water soluble, and electrically conductive. Therefore, when these adhere, image quality deteriorates (bona, contrast decreases), the chemical action of the adhered substances and the concentration of corona current on the adhered parts occur, and the surface of the photoreceptor deteriorates.

In general, the A-81 photoreceptor requires a higher corona current than the conventional Se photoreceptor, and the amount of deposition due to corona discharge is also large.

The above-mentioned adhesion caused by corona discharge is a problem that occurs in most photoreceptors, regardless of the type of photoreceptor, and there has been a need to develop photoreceptors with even better surface properties.

As mentioned above, an object of the present invention is to provide a photoreceptor with even better durability against surface deterioration.

It has been found that the above object can be achieved by treating the surface of the photoreceptor with a surface treatment agent. For example, for a photoreceptor in which amorphous silicon is formed as a photoreceptor layer on a conventionally used substrate, or a photoreceptor having a surface retaining layer of an inorganic compound thereon, the photoreceptor may be used immediately after manufacturing, or before use or During use, the surface of the photoreceptor is treated with a surface treatment agent. When surface treatment is performed during use, the treatment may be repeated at appropriate intervals.

The surface treatment may be carried out by applying a surface treatment agent to the surface of the photoreceptor by an appropriate means, and making sure that no excess surface treatment agent remains on the surface. For example, it may be applied using a cloth, fibrous or sponge material, or a roller or blade.

Conveniently, a roller whose surface is made of cotton or fiber is impregnated with a surface treatment agent, and the roller is rolled over the surface of the photoreceptor to apply the surface treatment agent to the surface of the photoreceptor. Thereafter, the surface of the photoreceptor to which the processing agent has been applied is dried using a heating device such as a lamp or by blowing cold or hot air. Alternatively, a processing agent is applied to the surface of the photoreceptor and spread by an appropriate method so that the agent is evenly distributed over the entire surface of the photoreceptor. Apply a solvent on it and wipe it with a cloth or wipe off the excess treatment agent by rolling a roller impregnated with the solvent. Next, heat it with a lamp or the like or use cold air.
Blowing hot air etc. dries the surface. Furthermore, if the solvent is highly volatile, air drying may be performed. Alternatively, the surface of the photoreceptor may be simply rubbed with a thin cloth impregnated with a processing agent. In short, it is sufficient that the processing agent is evenly attached to the entire surface of the photoreceptor. Further, the surface treatment is not limited to one time, but may be repeated as many times as necessary.

As the surface treatment agent, a substance that is chemically stable, has high electrical resistance, exhibits water repellency, and can reduce surface frictional resistance (that is, has lubricity) is used.

Examples of surface treatment agents include silicone oil, silicone grease, polymers of organosilicon compounds such as silicone oil, fluororesins such as Teflon, hydrocarbons such as paraffin,
Includes saturated fatty acid monometallic soaps such as stear, phosphoric acid, palmitic acid, lauric acid, and cerotic acid. As a surface treatment agent, these compounds may be used alone, but a combination of them may be used to further enhance the effect. Particularly preferred are silicone oil or silicone grease.

The surface treatment agent may be applied to the photoreceptor by any method as described above, but for example, it may be applied using a solvent suitable for the surface treatment agent used, such as benzene, toluene, trichlorethylene, acetone, etc. Good too.

Additives can also be mixed into the surface treatment agent.

For example, when using silicone grease, it has been recognized that deterioration in image quality can be prevented over a long period of time by mixing ultrafine powder of Sin, Si, or N4 into the silicone grease and applying the coating. This seems to be because silicone is compatible with silicon compounds and maintains a strong bond on the surface of the photoreceptor, and the ultrafine powder mediates these bonds and maintains a stable state over a long period of time.

Although it is not possible to completely avoid the adhesion of contaminants caused by corona discharge through surface treatments, these surface treatments can weaken the adhesion force and easily remove contaminants. Its effectiveness has been fully confirmed in the general cleaning process of actual equipment such as printers. Although these surface treatments are effective over a relatively long period of time, they may not be permanent. Therefore, it is effective to sequentially perform surface treatments as necessary. Since the processing method itself is simple as described above, such a process can be easily incorporated into an actual device.

The adhesion of contaminants to the photoreceptor surface is caused by corona discharge, and is an almost unavoidable problem regardless of the type of photoreceptor.The surface treatment of the present invention can reduce the tendency for contaminants to adhere to the surface of the photoreceptor. It can be applied to all photoreceptors. In particular, when the photosensitive layer is made of amorphous silicon (it can be a single layer or multiple layers), a-8i is extremely hard compared to other conventionally used photoreceptors, so it is necessary to scrape off part of the paper during transfer. Fine powders adhere and these form compounds with corona discharge products, promoting deterioration of the photoreceptor surface. However, according to the present invention, the surface is treated with a treatment agent that is water repellent and has the effect of reducing surface friction resistance. By applying this, it is possible to reduce the adhesion of such contaminants and reduce their influence. The same thing can be said about the case where a protective layer of a-8iNz is provided on the a-81 layer.
The surface treatment of the invention can be applied on top of the protective layer with excellent results. The reason why water repellency is effective against adhesion is not clear, but it is thought to be related to the fact that many pollutants are relatively water-soluble.

Patent Applicant: Stanley Electric Co., Ltd. Agent: Patent Attorney Yasu Kaizu Tamayo: Patent Attorney Hirayama - Procedural Amendment (Method) March 8, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the Case 1981 Patent Application No. 193343 2° Invention c7)
Name: Electrophotographic photoreceptor 3, Person making the amendment: Relationship with the case: Patent applicant: 4, Agent: 105 Procedural amendment (voluntary) November 4, 1980, Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office 1, Indication of the case: Showa 1957 Patent Application No. 193343z, Invention name: Electrophotographic photoreceptor 3, Relationship with the case of the person making the amendment Patent applicant: 4, Attorney: 105 7, ``Detailed description of the invention'' in the specification to be amended ” column will be corrected to “amine.”

(2) Same book, page 8, line 6 [5i02mata4maS i
3 Correct the - in N4 to ``of silicon oxide such as Ir5so2 or silicon nitride such as 5iBN4.

Claims (5)

[Claims] (1) The surface has been treated with a surface treatment agent selected from the group consisting of polymers of organosilicon compounds having lubricity and water repellency, fluororesins, paraffins, saturated fatty acids, metal soaps, and mixtures thereof. An electrophotographic photoreceptor having a photosensitive layer made of amorphous silicon, characterized by: (2) The electrophotographic photoreceptor according to claim 1, wherein the surface treatment agent comprises silicone grease, silicone oil, or a mixture of silicone oil. (3) The electronic photographic photoreceptor according to claim 1 or 2, wherein the surface treatment is performed by applying or rubbing the surface treatment agent onto the surface of the photoreceptor and then wiping the surface. 8 photoreceptors. (4) The electrophotographic photoreceptor according to any one of Claim 1JI11, 2, or 3, wherein the photoreceptor has a retention layer of an inorganic compound on the amorphous silicon photosensitive layer. (5) The electrophotographic photoreceptor according to claim 4, wherein the n-retaining layer is a-8IN,r.