JP2892420B2 - Cleaning equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an image carrier in an image forming apparatus such as an electrophotographic copying machine or a printer.

2. Description of the Related Art As one of cleaning devices for effectively removing toner remaining on an image carrier of an image forming apparatus, an electrically insulating or biased conductive fur brush is rotated with respect to the surface of the image carrier. There is known an apparatus of a system in which toner remaining on the surface of an image carrier is mechanically scraped by rubbing, and at the same time, electrostatically adsorbed and removed.

[Problems to be Solved by the Invention] In such an apparatus using an insulative fur brush, the fur brush is rotated at a high speed while being in contact with the image carrier with a relatively strong force, thereby causing friction with the image carrier. The brush is configured to charge the brush by charging to perform the electrostatic attraction. For this reason, there are problems such as damage to the image carrier surface due to high-speed rubbing of the fur brush and toner scattering caused by high-speed rotation of the brush.

On the other hand, in an apparatus using a conductive fur brush,
The fur brush is connected to an external power supply with the opposite polarity to the charging polarity of the toner, and the residual toner is electrostatically attracted to the brush by biasing the fur brush to an appropriate potential. Requires a stable external power supply or control device, which increases the number of components and increases the cost.

Therefore, an object of the present invention is to provide a cleaning device capable of performing effective cleaning with a simple configuration.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a cleaning device for removing toner remaining on an image carrier with a conductive fur brush, wherein the fur brush is connected to a self-biasing means. And electrically grounded.

In order to solve the above problem, the present invention removes toner remaining on the image carrier from the surface of the image carrier by rubbing the surface of the image carrier by being electrically grounded through a self-biasing means. In a cleaning device having a fur brush, a collecting roller provided in contact with the fur brush and removing toner attached to the fur brush from the fur brush, and a scraper for scraping off the toner attached to the collecting roller from the collecting roller, the toner is: The collection roller is made of magnetic toner, has a sleeve that magnetically attracts the toner attached to the fur brush, the sleeve is provided in an electrically floating state, and the self-biasing means uses the fur brush to transfer the image to the fur brush. It is selected so as to self-bias in a direction opposite to the polarity of the toner and higher than the bright portion potential of the image carrier due to the charge on the carrier. Characterized in that it is a constant-voltage diode or a varistor is.

[Operation] According to such a means, the fur brush is self-biased by the self-biasing means to an optimum value for cleaning the toner, and effectively adsorbs and removes the toner on the image carrier.

EXAMPLES The present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 denotes an image carrier having an appropriate photoconductor on the outer peripheral surface of a conductive drum made of aluminum or the like which is electrically grounded, and rotates in a direction indicated by an arrow A during operation.
A charging device 2 is provided around the image carrier 1 to uniformly charge the surface of the image carrier to a specific polarity in accordance with the rotation direction A. An exposure device 3 for forming an electrostatic latent image having a dark portion potential and a bright portion potential, supplying magnetic toner to an image carrier surface by an electrically biased magnetic sleeve, and developing the electrostatic latent image into a toner image. Developing device 4, a transfer device 6 for transferring the toner image onto a transfer material such as paper supplied in close contact with the surface of the image carrier, and a charge removing device for the transfer material electrostatically adhered to the surface of the image carrier. Separation device 7 that separates the toner, and cleaning device 1 that removes toner remaining on the surface of the image carrier after transfer
0, and a static elimination lamp 8 for static elimination of the surface of the image carrier before the next copying step to recover its fatigue.

The transfer material is supplied from an appropriate paper feeder, and is supplied to the transfer device 6 by a timing roller 9 in synchronization with the rotation of the image carrier 1. The transfer material is discharged from the back surface thereof by the transfer device 6 with a polarity opposite to that of the toner image, whereby the toner image is transferred from the image carrier to the transfer material.
Is separated from the image carrier by the action of, and is conveyed to a fixing device (not shown) by the conveyance belt.

The cleaning device 10 is roughly divided into a conductive fur brush 11 arranged so as to come into contact with the surface of the image carrier 1 over an appropriate range, a collecting roller 12 arranged in contact with the fur brush 11, and a collecting roller. And a screw device 14 disposed in contact with the scraper 13.

The fur brush 11 has a configuration in which a number of conductive brush fibers 17 are adhered or implanted to the outer peripheral surface of the conductive sleeve 16 while maintaining electrical conductivity. The sleeve 16 is rotatably supported by a bearing (not shown) with respect to the cleaning device main body, and rotates in a direction indicated by an arrow B by an appropriate driving means. At this time, the brush fibers 17 rub against the image carrier and adsorb the toner remaining thereon. Electrically sleeve
16 is grounded through self-biasing means 18 such as a constant voltage diode or a varistor. Self-biasing means 18
May be a constant voltage diode or varistor selected to self-bias to a polarity opposite to the polarity of the toner and somewhat greater than the background potential of the image carrier due to the charge on the image carrier. preferable. For example, in an experiment, when the potential of the dark portion of the electrostatic image of the image carrier is set to about 480 V, the potential of the light portion is set to about 100 V, and the bias of the developing sleeve is set to about 150 V, the potential of the fur brush 11 becomes about 120 V. It was confirmed that the best cleaning was performed when the bias means was used.

Since the recovery roller 12 uses magnetic toner in this example, it is formed of a rotatable non-magnetic sleeve containing a fixed magnet therein, and the sleeve rotates in the direction indicated by the arrow C. This cleave is electrically floating and not grounded.

In the above-described configuration, the residual toner remaining on the surface of the image carrier 1 after the transfer is mechanically scraped off by the fur brush 11 rotating in contact with the surface of the image carrier over an appropriate range. The toner is electrostatically attracted and removed from the surface of the image carrier by the fur brush 11 which is self-biased to the opposite polarity to the toner by the means.

The toner adhering to the fur brush 11 is magnetically attracted to the roller 12 from the brush surface by the magnetic force of the collection roller 12 and transferred, and the brush is provided again to the image carrier surface in a cleaned state.

In addition, the toner adsorbed on the collection roller 12 is
The scraped toner is scraped off from the roller surface by 13, and the scraped toner is collected by a screw device 14 into a waste toner bottle.

[Effects of the Invention] As described above, according to the present invention, good cleaning is provided for a long time without requiring an external power supply or a complicated control device.

[Brief description of the drawings]

FIG. 2 is a side view showing a main part of the cleaning device according to the present invention. 1 ... image carrier, 11 ... fur brush, 12 ... collection roller, 13 ... scraper, 14 ... screw device, 16 ... conductive sleeve, 17 ... conductive brush fiber, 18 ... self-bias means.

Claims (1)

(57) [Claims] A fur brush which is electrically grounded via self-biasing means and rubs the surface of the image carrier to remove toner remaining on the image carrier from the surface of the image carrier; A cleaning roller that is provided in contact with a brush and removes the toner attached to the fur brush from the fur brush, and a scraper that scrapes the toner attached to the collection roller from the collection roller; The toner is a magnetic toner, the collection roller has a sleeve for magnetically adsorbing the toner attached to the fur brush, the sleeve is provided in an electrically floating state, and the self-biasing means is provided. Moves the fur brush in the opposite direction to the polarity of the toner due to the charge on the image carrier,
And a constant voltage diode or a varistor selected so as to self-bias to a potential higher than the bright portion potential of the image carrier.