JPH0544675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner removing device for an electronic copying machine.

Generally, in an electronic copying machine, a photoreceptor drum serving as an image carrier is charged, and light reflected from a document is sent to the surface of the photoreceptor drum, and the surface of the photoreceptor drum is Toner is attached to the formed electrostatic latent image, and then transferred to the paper surface as the photosensitive drum rotates.

In such electronic copying machines, the transfer rate (the rate at which toner adheres to the paper surface during transfer) is about 40 to 60%, so toner remains on the surface of the photosensitive drum after transfer, and this residual toner is The toner is removed by a toner removing device installed near the photosensitive drum. This toner removing device is configured to scrape off residual toner by bringing the edge portion of a blade made of an elastic body into strong pressure contact with the surface of the photosensitive drum. This type of toner removal device is suitable for, for example, a photosensitive drum that has a so-called multilayer structure consisting of a photosensitive layer and a dielectric layer, but for photosensitive drums where the photosensitive layer is directly exposed on the surface, there may be scratches on the surface. occurs, impairing the specularity of the surface of the photosensitive layer and causing a significant shortening of the life of the photosensitive layer.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reliably and effectively remove toner remaining on the photosensitive drum in a transfer machine without causing scratches on the surface of the photosensitive drum. An object of the present invention is to provide a toner removing device for an electronic copying machine.

Hereinafter, the present invention will be specifically described based on an embodiment shown in the drawings. FIG. 1 shows a residual toner removal device of an electronic copying machine. In the electronic copying machine of this embodiment, a photosensitive drum 1 rotates in the direction of arrow X (clockwise) while charging, exposing, developing, transferring, and removing residual toner. It is configured so that it can be executed sequentially. The photosensitive drum 1 has a configuration in which a photosensitive layer 3 is formed on the surface of a cylindrical conductive drum 2, and is in a grounded state. On the surface of the photosensitive drum 1 (the surface of the photosensitive layer 3), there is an edge portion (pointed ridgeline portion) 6 of a blade 5 that scrapes off the toner 4 remaining on the surface of the photosensitive drum 1 after transfer.
A and A are in close contact with each other. This blade 5 is made of an elastic material having conductivity, and is hereinafter referred to as a conductive blade.
This conductive blade 5 is formed into a substantially rectangular rod shape as a whole, and its lower end is cut out so that the side facing the photosensitive drum 1 has a slightly acute angle.
The aforementioned edge portion 6a that contacts the surface of the photosensitive layer 3 is formed, and an edge portion (pointed ridgeline portion) 6b is formed on the opposite side of this edge portion 6a. The conductive blade 5 has a holder 7 disposed near the photosensitive drum 1 so as to cover three surfaces of its upper end.
It is held in the fitting groove 8 of. The holder 7 is electrically conductive and is supported by a shaft 9 so that the edge portion 6a contacts the surface of the photosensitive layer 3 with a predetermined pressure. In addition, the holding body 7 is connected to the DC power supply 1
0, and a potential having the same polarity as the charge held by the remaining toner 4 is applied to the conductive blade 5 via the holder 7.

Further, a conductive roller 11 is arranged near the photosensitive drum 1 and the edge portion 6b. This conductive roller 11 is rotated in the direction of arrow Y (clockwise), is electrically connected to a DC power source 12, and is applied with a potential having a polarity different from the charge held by the residual toner 4. The edge portion of a blade 13 made of a dielectric material is pressed into contact with the lower end surface of the conductive roller 11. Further, a shielding plate 14 is disposed below the conductive roller 11 and near the photosensitive drum 1 to prevent floating and falling toner from being attached to the photosensitive layer 3 again.

Next, the operation of the toner removing device configured as described above will be explained. Photosensitive drum 1 after transfer
Residual toner 4 adhering to the surface of the photosensitive layer 3
is carried in the direction of arrow X and sent to the conductive blade 5. In this case, since the edge portion 6a of the conductive blade 5 is in contact with the surface of the photosensitive layer 3, the residual toner 4 that has been sent is scraped off by the edge portion 6a and removed. Further, since a potential having the same polarity as the charge held by the residual toner 4 is applied from the DC power supply 10 to the conductive blade 5, the second
As shown in the figure, for example, assuming that the residual toner 4 has a negative charge, the conductive blade 5 is negatively charged, so the conductive blade 5 and the positively charged conductive drum 2
A dielectric flux φ1 is generated between the photosensitive layer 3 and the photosensitive layer 3. Further, the surface charge on the photosensitive layer 3 is electrostatically neutralized because the potential polarity is different from that of the conductive blade 5, and the surface charge on the photosensitive layer 3 is equalized by the charge from the conductive blade 5. The toner adsorption force gradually becomes weaker as it approaches the conductive blade 5. As a result, residual toner 4 adhering to the photosensitive layer 3
is blown away and removed by the electrostatic repulsion action of the dielectric flux φ1. In this case, in the vicinity of the conductive blade 5, the toner adsorption force is weak and the dielectric flux φ1 is concentrated, so the toner removal effect in this area is extremely high. In this way, the residual toner 4 is effectively removed by the cooperation of the scraping action by the contact of the conductive blade 5 and the electrostatic repelling action.

A conductive roller 11 is disposed near the edge portion 6b of the conductive blade 5 and the photosensitive drum 1, and a potential of a different polarity from the charge held by the residual toner 4 is applied. As shown in FIG. 2, if the residual toner 4 has a negative charge, the conductive roller 11 is charged with a positive charge, so the edge portion 6b of the conductive roller 11 and the conductive blade 5 Between, the dielectric flux φ2
occurs. As a result, as mentioned above, the photosensitive layer 3
The floating toner removed from the conductive roller 11 is accelerated by the electrostatic repelling action of the dielectric fluxes φ1 and φ2, and is attracted toward the surface of the conductive roller 11. Then, the toner adsorbed to the conductive roller 11 is transferred to the blade 1 as the roller 11 rotates.
3 and scraped off by the edge. In this case, since the shielding plate 14 is disposed near the photosensitive layer 3, the scraped toner does not adhere to the photosensitive layer 3 again.

Note that this invention is not limited to the above embodiments, and can be modified in various ways without departing from the scope of the invention. For example, the conductive roller may be rotated in the opposite direction to that of the above embodiments, and the blade pressed against the roller may be rotated. The blade may be arranged so that the edge portion faces the rotational direction of the roller, and the toner scraped off from the conductive roller is conveyed in a predetermined direction so that the toner can be reused. It's okay. Furthermore, although the photosensitive drum in the above embodiment has only a photosensitive layer formed on the surface of the conductive drum, it is of course possible to use the photosensitive layer in a multilayered structure including a dielectric layer.

As described in detail above, the present invention provides a drum on which an image is formed by toner adhered to the surface, and an elastic member that brings an edge portion into contact with the drum surface to remove toner remaining on the drum surface. and a DC power source that applies a potential of the same polarity as the charge held by the residual toner to the conductive blade, and an electrical repulsive force is generated between the conductive drum and the residual toner. Since the residual toner is removed by the action of the conductive blade, the residual toner is effectively removed by the cooperation of the scraping action caused by the contact of the conductive blade and the electrostatic repelling action. Therefore, toner can be sufficiently removed without pressing the edge portion of the conductive blade against the drum surface with such strong pressure as to damage the mirror surface of the drum surface. Therefore, no scratches occur on the surface of the photosensitive drum, the specularity of the photosensitive drum is maintained, and the photosensitive drum can withstand long-term use. Furthermore, since a conductive roller is arranged near the conductive blade to which a potential of a polarity different from the charge held by the remaining toner is applied, the toner removed from the photosensitive drum is attracted to the conductive roller. This prevents the toner from adhering to the surface of the photosensitive drum again.

[Brief explanation of the drawing]

The drawings show an embodiment of the toner removal device for an electronic copying machine according to the present invention, and FIG. 1 is a schematic configuration diagram;
Figure 2 is an enlarged view of the main parts. DESCRIPTION OF SYMBOLS 1... Drum, 4... Residual toner, 5... Conductive blade, 6a, 6b... Edge portion, 10, 1
2... DC power supply, 11... Conductive roller.

Claims (1)

[Claims] 1. an image carrier on which an image is formed by toner attached to the surface; an elastic conductive blade that brings an edge portion into contact with the surface of the image carrier to remove toner remaining on the surface of the image carrier; a DC power source that applies a potential of the same polarity as the charge held by the residual toner to the elastic conductive blade; and a DC power supply that is placed near the elastic conductive blade and attracts the toner removed by the elastic conductive blade to its surface. A toner collection rotating roll that carries and conveys the toner in a direction away from the surface of the image carrier, and a scraper that is in pressure contact with the toner collection rotation roll and scrapes off the adsorbed toner, and the scraper is provided with a scraper that scrapes off the adsorbed toner. An electronic copying machine characterized in that the residual toner is removed from the surface of the image carrier by applying an electrical repulsive force between the two, and is transported in a direction away from the surface of the image carrier and collected. Toner removal device.