JPS6325354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polishing the surface of an electrophotographic photoreceptor.

The circumferential surface of the photoconductor, for example, the photoconductor drum, may attract foreign matter such as dust floating inside the copying machine due to the electric field caused by the electric charge applied to the circumferential surface, or may adhere to the transfer material due to contact with the transfer material. Foreign matter that has been attached to the surface migrates and adheres to the circumferential surface of the photosensitive drum. This foreign matter has an adverse effect on the formation and development of an electrostatic latent image, causing so-called image deletion, so the circumferential surface of the photosensitive drum must be polished. and must be removed.

Conventionally, the method of polishing the circumferential surface of a photosensitive drum involves mixing an abrasive such as cerium oxide into the developer.
a polishing member that electrostatically attaches the developer to an electrostatic latent image formed on the circumferential surface of a rotating photosensitive drum to develop the image, and rubs the developing agent on the circumferential surface of the photosensitive drum after transfer;
For example, a cleaning blade is used to remove residual developed images on the circumferential surface of the photosensitive drum and at the same time perform polishing work.

However, in the above-mentioned conventional method, since the developer containing abrasive is not attached to the circumferential surface of the photosensitive drum corresponding to the white background part of the document, the developer containing the abrasive is not attached to the circumferential surface of the photosensitive drum corresponding to the white background part of the original. There is a drawback that when a portion is formed, it is not possible to polish foreign matter adhering to that portion.

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional methods described above, it is an object of the present invention to always uniformly polish the circumferential surface of a photosensitive drum, regardless of the form of an electrostatic latent image formed on the circumferential surface of the photosensitive drum.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a photosensitive drum, and a photosensitive member 2 comprising a conductive layer, a photoconductive layer, and a surface insulating layer is provided on the circumferential surface of the photosensitive drum. The photosensitive drum 1 rotates in the direction of the arrow, and its peripheral surface is sequentially subjected to primary charging by a charger 3, simultaneous exposure and neutralization by a charger 4, and full-surface exposure by a lamp 5 to form an electrostatic latent image corresponding to the original image. do. The electrostatic latent image is developed and visualized by a developing device 6, and is transferred onto a transfer material P by a transfer charger 7. The developed image remaining on the circumferential surface of the photosensitive drum is removed by a cleaning blade 8.

A transparent document table 9 on which a document O is placed is provided above the photosensitive drum 1 so as to be movable back and forth. Projected onto the surrounding surface.

In the moving direction of the document table 9, the scanning length L of the document O by the optical system is set with a margin longer than the length L1 of the document O, so that the document O is close to both ends of the document O. The non-image area will also be exposed to light on the circumferential surface of the photosensitive drum. Further, the primary charging on the circumferential surface of the photosensitive drum is also matched to the scanning length L of the document table 9.

The present invention focuses on the above-mentioned non-image area, and a colored member 12 with low light reflectivity such as black or gray is placed on at least one of the non-image areas, for example on the scanning start end side, in the width direction of the document table 9, that is, on the document table 9. It is placed in a direction that intersects the direction of movement.

When the coloring member 12 is placed in this way, the reflected light from the coloring member 12 corresponds to the dark part of the document, and the electric charge in the generatrix direction of the circumferential surface of the photosensitive drum corresponding to the coloring member 12 is constant in the circumferential direction. Since the length of the abrasive does not disappear, a developer application area is formed, and during subsequent development using a developing device, a developer adhesion portion 13 containing a band-shaped abrasive is formed in the area as shown in FIG.

This adhesion part 13 is used as the transfer material P in the next transfer process.
Therefore, when the adhering portion 13 is rubbed by the cleaning blade 8 during subsequent rotation of the photosensitive drum, the abrasive in the developer polishes the circumferential surface of the photosensitive drum and removes the foreign matter. It is.

FIG. 3 shows another embodiment of the invention. In an electrophotographic process using a photoreceptor having an insulating layer on a photoconductive layer and a negatively charged developer, the surface potential of the image area is (+) as shown in Figure 3A and B. ) side is uneven, but in order to prevent developer from adhering to the non-image area, so-called blank exposure is applied to the non-image area to make the surface potential negative as shown in b in Figure 3A. is being carried out.

In the present invention, the blank exposure is interrupted as shown in c in FIG. 3B, and the surface potential of the interrupted portion is maintained at a polarity opposite to that of the developer to form a developer-attached area. It is something. In this case, depending on the way the blank exposure is interrupted or some types of electrophotography, the developer may not adhere to the above area sufficiently. It is preferable to control the primary charging voltage on the circumferential surface of the drum to be high.

As described above, the present invention forms a series of developer-attached areas in a part of the non-image area of the photoreceptor in a direction intersecting the direction of movement of the photoreceptor, so the area is rubbed with a polishing member such as a cleaning blade. By rubbing, the surface of the photoreceptor can be efficiently and uniformly polished to obtain a good copy image, regardless of the form of the original image, that is, the electrostatic latent image. In addition, in the past, a relatively high proportion of abrasive (1 to 3%) was mixed into the developer in consideration of the white background of the original, but the abrasive does not play a role in development at all, or
In some cases, the development action may be inhibited. In the present invention, since the developer can be reliably attached to the developer-attached area of the non-image area of the photoreceptor, the proportion of abrasive of 1% or less is sufficient and does not impede the development action in any way. .

[Brief explanation of drawings]

Figure 1 is a schematic diagram of an embodiment embodying the method of the present invention, Figure 2 is a perspective view of a photosensitive drum, and Figures 3A and B.
are graphs showing the surface potentials of photosensitive drums according to the prior art and other embodiments of the present invention, respectively. 1 is a photosensitive drum as a photoreceptor; 13 is a developer adhesion section;

Claims (1)

[Scope of Claims] 1. When polishing the surface of the photoreceptor with a polishing member that attaches a developer mixed with an abrasive to the surface of a moving electrophotographic photoreceptor and rubs it against the surface of the photoreceptor, the surface of the photoreceptor is polished. A method for polishing the surface of an electrophotographic photoreceptor, comprising forming a series of developer-attached areas in a part of the non-image area in a direction intersecting the moving direction of the photoreceptor. 2. The developer adhesion area is formed by a colored member with low light reflectance placed in a non-image area that is close to the image area on the document table and exposed to the surface of the photoreceptor. The method for polishing the surface of an electrophotographic photoreceptor according to item 1. 3. The electrophotographic photoreceptor according to claim 1, wherein the developer attachment area is formed by interrupting blank exposure applied to the surface of the photoreceptor after forming an electrostatic latent image on the surface of the photoreceptor. How to polish the surface.