JPH02763Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a magnetic brush cleaning device used in a recording device using powder toner.

In order to sufficiently remove the residual toner on the surface of the image carrier with the above-described magnetic brush cleaning device, a magnetic brush formed of a cleaning carrier of magnetic particles must rub the surface of the image carrier at a considerable speed. The scraping action caused by rubbing is one of the important factors in the cleaning action of the magnetic brush. Therefore, in order to improve the cleaning effect, the rotational speed of the magnetic brush must be increased, and as a result, in the conventional magnetic brush cleaning device, the carrier and toner were scattered around the magnetic brush.

Further, the image carrier and the residual toner have charges of opposite polarity, and an electrostatic attraction force is exerted between them. Therefore, even when scraping with a magnetic brush, it is necessary to apply a bias voltage of opposite polarity to the charge of the toner to the magnetic brush side. If the electrostatic attraction between the image carrier and the toner is strong, the bias voltage of the magnetic brush must be increased accordingly, but this requires improving the pressure resistance of the device, Since problems such as the occurrence of lightning strikes on the body surface occur, the voltage value of the bias voltage is limited to an upper limit. Therefore, it is necessary to weaken the electrostatic attraction between the image carrier and the toner before rubbing with the magnetic brush, and in conventional magnetic brush cleaning devices, the discharge electrode for this purpose is placed in front of the magnetic brush cleaning device. It is being established that

This invention can weaken the electrostatic attraction between the image carrier and the toner before rubbing with the magnetic brush, can prevent the occurrence of stains due to carrier and toner scattering, and has improved cleaning performance. To provide a magnetic brush cleaning device that can increase the

The present invention provides a cleaning device that removes toner on the surface of the image carrier by bringing a magnetic brush into contact with the surface of the image carrier. A magnetic brush cleaning device is characterized in that it is provided with an elastic roller that rotates in the same direction as the moving direction of an image carrier surface.

Hereinafter, the present invention will be explained based on illustrated examples.

The figure is a sectional view showing an example of the magnetic brush cleaning device of the present invention.The outer circumferential surface of the magnetic brush sleeve 1 rotating clockwise is provided with a cleaning device by the magnetic force of the magnet of the magnet body 2 fixedly provided inside. The carrier is attracted to form a magnetic brush 3.
The magnetic brush 3 moves with the rotation of the magnetic brush sleeve 1 and rubs the surface of the image carrier 4 which rotates clockwise. A bias voltage with a polarity that attracts the toner on the surface of the image carrier 4 is applied to the magnetic brush sleeve 1 by a bias power supply 5, and the magnetic brush 3 is moved by sliding and the attraction force of the bias voltage. The toner on the surface of the image carrier 4 is captured and transferred to the collection roller 6 side. A bias voltage having a polarity that attracts the toner captured by the magnetic brush 3 and whose voltage value is higher than that of the bias voltage of the magnetic brush sleeve 1 is applied to the collection roller 6 by a bias power supply 7. Stick collection roller 6
captures the toner transferred by the magnetic brush 3 on its surface and carries the captured toner toward the scraping blade 8 by rotating counterclockwise. The toner falls onto a conveying means 9 such as a screw conveyor by the blade 8, and is conveyed by the conveying means 9 to an appropriate place such as a developing device (not shown).

The above configuration is the same as that of the conventional magnetic brush cleaning device, but the magnetic brush cleaning device of the present invention further includes an elastic force that contacts the surface of the image carrier 4 and rotates prior to the contact of the magnetic brush 3. A roller 10 is provided. The rotation of the elastic roller 10 may be a driven rotation given by the image carrier 4 or an active rotation in the same direction. It doesn't cause much of a burden.
In the illustrated elastic roller 10, an elastic layer 10a on the surface is made of a conductive elastic material, and a power source 11 is connected to the elastic layer 10a via a shaft 10b.
An alternating current voltage or a polar bias voltage that attracts the toner on the surface of the image carrier 1 is applied to lower the potential of the image carrier 1 and the toner.

By providing such an elastic roller 10, toner and carrier that are scattered downward due to the sliding friction of the magnetic brush 3 and leaked from the casing of the magnetic brush portion are received by the elastic roller 10, which is different from the conventional method. The generation of dirt as in the magnetic brush cleaning device is eliminated. In addition, the elastic layer 1
When an AC voltage is applied to 0a, the potential of the image carrier 4 and residual toner is actively lowered, and the cleaning performance is improved without increasing the bias voltage at the magnetic brush 3. When a bias voltage is applied to the layer 10a, the elastic roller 10 also actively removes residual toner, resulting in improved overall cleaning performance. Further, even if the elastic layer 10a is grounded without applying a voltage, the potential of the image carrier 4 and the residual toner is lowered, and the same cleaning performance improvement effect as when an AC voltage is applied can be obtained. Further, even when the elastic layer 10a of the elastic roller 10 is insulative, the electrical charge of the elastic layer 10a may attract and remove the toner.
Alternatively, the elastic roller 10 lowers the residual toner and the potential on the surface of the image carrier 4, thereby improving the overall cleaning performance.

The toner that adheres to the surface of the elastic roller 10 and is removed from the surface of the image carrier 4 is removed by the scraping blade 12.
The toner is removed from the surface of the elastic roller 10 and stored in a toner reservoir.

[Brief explanation of the drawing]

The figure is a sectional view showing an example of the magnetic brush cleaning device of the present invention. 1... Magnetic brush sleeve, 2... Magnet body, 3
... Magnetic brush, 4 ... Image carrier, 5 ... Bias power supply, 6 ... Collection roller, 7 ... Bias power supply, 8 ... Scraping blade, 9 ... Conveyance means, 10 ... Elastic roller, 10a...Elastic layer,
10b...axis, 11...bias power supply, 12...
Scraping blade.

Claims (1)

[Claims for Utility Model Registration] 1. In a cleaning device that removes toner on the surface of an image carrier by bringing a magnetic brush into contact with the surface of the image carrier, the cleaning device contacts the surface of the image carrier before the magnetic brush and removes toner from the surface of the image carrier at the contact position. A magnetic brush cleaning device comprising an elastic roller whose surface rotates in the same direction as the direction of movement of the image carrier surface. 2. The magnetic brush cleaning device according to claim 1, wherein the elastic layer on the surface of the elastic roller is conductive, and a bias voltage is applied to the elastic layer. 3. The magnetic brush cleaning device according to claim 2, wherein the bias voltage is an alternating current voltage. 4. The magnetic brush cleaning device according to claims 1 to 3, wherein a blade for scraping off toner adhering to the elastic roller is provided.