JPS6247308B2 - - 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 then the surface is reused so that the surface can be copied again. .

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 10,000 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 quality of the copied image deteriorates 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 provides a photoreceptor comprising an abrasive material containing a polishing agent and a dispersant thereof that have a good polishing effect on the glassy selenium surface, and an abrasive agent added to the abrasive material when there are scratches on the surface. The number of reproduced copies is increased by obtaining a good surface condition using abrasive materials. 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> Magnesium oxide (MgO) was used alone as the abrasive, and isopropyl alcohol 70 was used as the dispersant.
%, water is 30%, and the proportion of MgO in the polishing liquid is 20%.
When polishing a used photosensitive drum with polishing liquid,
The surface roughness was about 0.02 .mu.m, and the number of copies before image deterioration was 20,000 to 25,000.

<Example 2> Magnesium oxide (MgO) 70 as abrasive
%, aluminum oxide (α-Al203 particle size 0.05μ
m) 30%. When a used photosensitive drum is polished with a polishing liquid in which the dispersant is 70% isopropyl alcohol and 30% water, and the ratio of the mixture of MgO and Al203 in the polishing liquid is 20%, the surface roughness is about 0.05 μm. The number of copies before image deterioration is 15,000 to 20,000. It can also remove shallow scratches.

<Example 3> Magnesium oxide (MgO) 50 as an abrasive
%, aluminum oxide (α-Al203 particle size 0.1μm)
50%. Dispersant is isopropyl alcohol 60
%, water is 40%, and when a used photosensitive drum is polished with a polishing liquid in which the ratio of the mixture of MgO and Al203 in the polishing liquid is 20%, the surface roughness is about 0.1 μm.
The number of copies before image deterioration was 10,000 to 15,000. It can also remove surface scratches.

As can be seen from the above examples, the abrasives include zinc oxide (ZnO), magnesium oxide (MgO), which have a polishing effect on the surface of vitreous selenium,
It uses tin dioxide (SnO ₂ ), ferric oxide (Fe203), or chromium oxide (Cr203) as a base material, and has a polishing effect on the glassy selenium surface as necessary. Mix 1 to 80% of diamond powder (C), silicon oxide (SiO2), silicon carbide (SiC), aluminum oxide (α-Al203, r-Al203), boron carbide (B4C), or glass powder, Further, by selecting the particle size between 0.05 μm and 1.0 μm, adjustment can be made depending on the surface condition of the used (reused) photosensitive drum.

Both the polishing agent and abrasive material mentioned above are powders, and it is necessary to disperse them in a solution in a good state before use. Therefore, a good dispersion state could be obtained by mixing 20-80% alcohol and 20-80% water as a dispersant, and adjusting the proportions of these in the polishing liquid to 10-50%.

As is clear from the above explanation, according to the abrasive material of the present invention, the resin coating of the used drum is removed,
It is possible to remove scratches, etc., and even after polishing, almost the same number of copies as a new drum can be obtained, and the dispersion state is good, and handling is easy, which has great practical effects.

Claims (1)

[Claims] 1. selected from the group of zinc oxide (ZnO), magnesium oxide (MgO), tin dioxide (SnO ₂ ), ferric oxide (Fe ₂ O ₃ ), and chromium oxide (Cr ₂ O ₃ ). one or more polishing agents, and diamond powder (C),
Silicon oxide (SiO ₂ ), aluminum oxide (α-
Al ₂ O ₃ r-Al ₂ O ₃ ) One or more abrasives selected from the group of silicon carbide (SiC) and boron carbide (BC) glass powder are dispersed in a dispersant whose main component is alcohol, and An abrasive material for a selenium photoreceptor, characterized in that the proportion of a mixture of a polishing agent and an abrasive material in the dispersant is set at 10 to 50% by weight. 2 Mixing ratio of abrasive to polishing agent: 1 to 87% by weight
The first claim characterized in that
Abrasive material for selenium photoconductor as described in . 3. Adjust the particle size of the polishing agent and abrasive from 0.05μm to 2.0μm.
The abrasive material for a selenium photoconductor according to claim 1, wherein the abrasive material is set to μm. 4 20-80% by weight of isopropyl alcohol and 80
The abrasive material for a selenium photoreceptor according to claim 1, characterized in that a dispersant consisting of ~20% by weight of water is used.