JPS622944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abrasive material for selenium photoreceptors used in electrophotographic devices and the like. In general, a selenium photoreceptor is constructed by depositing vitreous selenium on the surface of a drum-shaped substrate, and by rotating the drum, the vitreous selenium surface is charged, exposed, developed, transferred, etc.
It is subjected to static elimination and cleaning treatment before being used for copying. During repeated copying, an organic resin film such as polystyrene, which is a component of the developer, is formed on the surface of such electrophotographic selenium photosensitive drums, resulting in a decrease in surface potential and a decrease in the density of the actual copied image.
This causes deterioration such as cracking.

The surface of a photosensitive drum in such a state is generally lightly polished by applying a polishing liquid containing an appropriate abrasive dispersed on a cloth, and the surface is reused to make the surface ready for copying. .

According to experiments, an unused photosensitive drum can be used for up to 20,000 hours before the image deteriorates due to the formation of a resin film.
Approximately 30,000 copies can be made. However, if a used photosensitive drum is recycled by polishing it with a polishing liquid containing coarse particles, it has the disadvantage that only about 5,000 copies can be made before the image deteriorates due to the formation of a resin film again. In view of these points, the present invention provides an abrasive material suitable for polishing the surface of a photoreceptor, thereby greatly increasing the number of copies of the photoreceptor.

According to surface polishing experiments conducted by the present inventors, the number of copies until a resin film is formed on the surface of a selenium photosensitive drum and the number of copies until deterioration of the copied image occurs depends on the roughness of the surface of the photosensitive drum after polishing. It has been found that the deterioration of the image during repeated copying is due to the formation of a resin film by the developer as well as the occurrence of scratches due to contact with paper, carrier adhesion, etc. Therefore, effective surface conditions for increasing the number of copies are low roughness and removal of scratches. The present invention aims to increase the number of reproduced copies by obtaining a good surface condition by using an abrasive material for a photoconductor containing an abrasive material having a good abrasive action on the glassy selenium surface and a dispersant thereof. It is. Examples will be described below.

Prior to the Examples, first, as a comparative experiment, a new drum (not polished) was measured, and the surface roughness was 0.01 μm or less, and the number of copies before image deterioration was 20,000 to 30,000.

Example 1 Aluminum oxide with a particle size of 0.05 μm was used alone as the abrasive, the dispersant was 20% isopropyl alcohol and 30% water, and a used photosensitive material was used with a polishing solution in which the proportion of aluminum oxide in the polishing solution was 20%. When the drum is polished, the surface roughness is about 0.05 μm, and the number of copies is 15,000 to 20,000 before the image deteriorates.
A shallow wound was also removed.

Example 2 Aluminum oxide with a particle size of 0.5 μm was used as the abrasive, and isopropyl alcohol 70 was used as the dispersant.
%, water is 30%, and when a used photosensitive drum is polished with a polishing solution containing 20% aluminum oxide, the surface roughness is approximately 0.5 μm.
The number of copies before image deterioration was 7,000 to 10,000.

Example 3 Silicon carbide with a particle size of 0.5 μm was used as the abrasive, and the dispersant was 70% isopropyl alcohol and 30% water.
%, and the same results as in Example 2 were obtained when a used photosensitive drum having scratches with a depth of 0.5 to 1 μm was polished with a polishing liquid in which the proportion of silicon carbide in the polishing liquid was 20%. Furthermore, when the surface of the photosensitive drum polished with the same polishing liquid was further polished with the polishing liquid of Example 1, the surface roughness was about 0.05 μm, scratches were removed, and the number of copies before image deterioration was 15,000. ~
It is 20,000 pieces.

As can be seen from the above examples, as an abrasive,
Diamond powder (C), silicon oxide (SiO ₂ )
Silicon carbide (SiC), aluminum oxide (α-
It is possible to use either Al ₂ O ₃ , γ-Al ₂ O ₃ ), or boron carbide (BoC) glass powder. Further, by selecting the particle size within a range of 0.5 μm or less, adjustment can be made depending on the surface condition of the used photosensitive drum.

All of the above-mentioned abrasives are powders, and must be dispersed in a solution in a good condition before use. Therefore, as a dispersant, alcohol 20 to 80%
A good dispersion state could be obtained by mixing 20 to 80% of water and adjusting the proportion of these in the polishing liquid to 10 to 50%. As is clear from the above description, according to the abrasive material of the present invention, the resin coating of the used drum can be removed, and it is also possible to remove scratches, etc., and the number of copies made can be almost the same as that of a new drum even after polishing. ,
Furthermore, it has a good dispersion state, is easy to handle, and has great practical effects.

Claims (1)

[Claims] 1 Diamond powder (C), silicon oxide (SiO ₂ ), silicon carbide (SiC), aluminum oxide (α
-Al ₂ O ₃ , γ-Al ₂ O ₃ ), boron carbide (BoC), and glass powder with a particle size of 0.5μ
An abrasive material for a selenium photoconductor, characterized in that it contains an abrasive of m or less and a dispersant whose main component is an alcohol.