JPS58142375A - Roll cleaner - Google Patents

Abstract

PURPOSE:To perform satisfactory cleaning without damaging a photoreceptor, by providing a porous cleaning roll which rotates reversely on the down stream of the 1st cleaner which rotates in the same direction as the rotating direction of a photoreceptor and is applied with the voltage of the polarity reverse to the polarity of the electric charge of residual toners. CONSTITUTION:A cleaning roll 2 which is of 20-40mm. diameter has a conductive elastic rubber material layer of 10<-6>-10<-10>mho/cm conductivity and is applied with the bias voltage of the polarity reverse to the electric charge that the residual toners 7 on a photosensitive drum 1 possesses through a protecting resistor 10 from an electric power source 6. The 2nd cleaning roll 3 is further provided on the downstream. The roll 3 has sponge 3b of an expandable resin on a roll shaft, and an insulating tube or the like is covered thereon at about 10- 100mum. Said roll rotates in the direction reverse to the rotating direction of the drum 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a field cleaning device used in an electrostatic recording device such as an electrophotographic copying machine.

In general, electrostatic recording devices use a drum with a photoconductor layer on its surface, a drum with a dielectric layer formed after trapping corona charging on the belt, and then exposing it to light to form a latent image. A latent image is formed by an ion flow or the like on the belt or belt using an ion control method or the like.

A drum or belt provided with a photoconductor layer or a dielectric layer for forming these latent images serves as an image carrier and is supplied with toner by a known electrophotographic development method, and is visualized as a toner image. The toner image on the image carrier is transferred onto a transfer sheet, and after the toner image has been transferred, residual toner is wiped off the image carrier in preparation for the next image formation.-G-4P
4-ru. As a method of wiping the residual toner on the image bearing member, there is a cleaning method using a cleaning method. The present invention relates to improvements to this roller cleaning device.

Conventionally widely used roller cleaning devices use, for example, an elastic lobe as a cleaning roller, and rotate the elastic roller in the opposite direction at the contact point to the moving direction of the image carrier to which residual toner has adhered, thereby rubbing the surface of the image carrier. For example, Japanese Patent Publication No. 49-12671 1 Japanese Patent Publication No. 50-37547, Japanese Patent Application Laid-Open No. 1852-1272
The proposals in Publication No. 40 and others fall into this category, for example, using a porous material such as cloth or foaming resin for the surface of the cleaning roller, or using a foaming material coated with an insulating resin film. I am using it. When the former porous roller is used, toner can be effectively removed from the image carrier, but it is difficult to remove toner that has adhered to the cleaning solar. Therefore, what makes it easier to scrape off the toner adhering to the cleaning reeler is the cleaning section with an insulating film.
In the case of a cleaning roller, the ability to remove toner from the surface of the image carrier is lower than that of a porous roller, so it is necessary to increase the rotational speed of the cleaning roller or increase the pressing force on the image carrier. If the rotational speed or pressing force of the cleaning roller increases, there is a risk of damaging the image carrier. In this case, if the amount of toner adhering to the image carrier is small, the load placed on the cleaning roller is small, and therefore there is little risk of damaging the image carrier.

Furthermore, conventionally, in order to reduce the burden on each cleaning roller, cleaning has been performed by bringing a plurality of cleaning rollers into contact with the image carrier.

For example, in the conventional cleaning method, including the proposal in Japanese Patent Application Laid-Open No. 50-3637, all of the cleaning rollers are rotated in the forward direction of the moving direction of the image bearing member. : This is a method in which the toner is made of conductive rubber and uses both electrostatic and physical adsorption force to perform IJ-Jung. In this method, the electrostatic adsorption force σ)
1, 1 and 1. .

The acting ratio is large, and the toner to be attracted is required to be in a uniformly charged state. In addition, in order to clean toner charged with the opposite polarity, if one of the cleaning rollers is applied with a bias of the opposite polarity to the other cleaning rollers, the polarity will be mixed. However, this method naturally requires multiple bias power supplies, making the device expensive.

The present invention uses a plurality of cleaning rollers to eliminate the disadvantages of using several cleaning rollers in the past, and to reduce the burden of cleaning per roller.
The purpose is to completely remove residual toner, and the above purpose is to remove residual toner on the image carrier, which is pressed against the peripheral surface of the image carrier and is rotatable in the same direction at the pressing point. An Nl cleaning reeler for removing toner (residual) toner is formed by forming an elastic body on the roller shaft that can apply a bias of opposite polarity to the toner retention property, and an image downstream of the first cleaning roller. A roller of an electrostatic recording device in which the cleaning roller Ii2 is an elastic roller whose surface is formed of a porous material and is pressed against the peripheral surface of the carrier and rotates in the opposite direction at the point of contact with the image carrier. This is accomplished by a cleaning device.

Hereinafter, the present invention will be explained in detail using wJw.

FIG. 1 shows a schematic lid diagram of a cleaning section of an electrophotographic photosensitive drum showing an embodiment using two cleaning rollers of the present invention.

The electrophotographic photosensitive drum 1, which rotates in a clockwise direction, has a cleaning roller 2 that is pressed toward the center of the photosensitive drum 1 by pressing spring members 8 provided at both ends and rotates as a result. The cleaning roller 2 on the upstream side has a diameter of 20 to 401 mφ and has a conductivity of lO to
A conductive elastic rubber material layer of 10 M/cm increases the diameter of the cow.
It is formed with a thickness of 50%, and the hardness of the elastic rubber is ~
65°, the conductive shaft 2aK is connected by the power source 6,
A bias voltage having a polarity opposite to that of the charge held by the residual toner 7 (polarity when a Se-based photoreceptor is used) is applied. The applied voltage is 1.0 to L, SKV, and the circuit is provided with a protection resistor lO in series.

Therefore, the cleaning roller 2 on the upstream side cleans the residual toner 7 adhering to the surface of the photoreceptor drum 141 using the suction force that bites into it with elasticity and the electrostatic suction force due to the bias. However, some of this residual toner 7 is charged in the opposite way to the original toner chargeability, and some of it has lost its charge, and these can be removed by cleaning.
＠The pressing force of the cleaning roller 2 is still limited by mechanical strength and the limit without damaging the photoreceptor.
The fact that the cleaning roller 2 performs complete cleaning is #i-.

Since the cleaning roller 2 applies a bias voltage,
It is appropriate to use conductive rubber, and the outermost layer of the roller can be left as is, or it can be covered with an insulating film or with a porous material to improve the physical and electrostatic adsorption of the toner. You can also do it. As the insulating film, a Teflon film or the like having a thickness of 10 to 100μ is used. is scraped off.

The toner 7' that was not cleaned by the cleaning roller 2 adhered to the photosensitive drum 1! It moves to the position of the elastic roller, which is the second cleaning roller, which is installed downstream of the blind. Hereinafter, the second cleaner roller will be referred to as the elastic roller 3. This elastic roller 3 is
In this example, there is a sponge (3bC foamed resin) on the roller shaft.
11. In order to form a film 3@ on the surface layer, a material coated with an insulating tube or the like having a thickness of about 10 to 100 μm is used.

This elastic roller 3 is pressed against the photosensitive drum by pressing spring members 9 provided at both ends thereof. It is pressed toward the center and rotates nine times in the opposite direction at the point of contact with the photoreceptor drum 1 by a power (not shown) to rub the surface of the photoreceptor and remove toner adhering to the photoreceptor. In general, ll! for the image carrier! The rubber hardness of the surface elastic body used for the rolling elastic roller 3 is 15~
A very soft material of 25° IM degree is preferred. Since this elastic roller 3 once cleans the remaining residue, its burden is small, and the cleaning can be done satisfactorily by the pressing force and rotational speed that do not damage the photoreceptor.

By applying a bias voltage to the cleaning roller 2 and applying electrostatic adsorption force, 90% of the remaining toner can be removed.
% can be cleaned. At this point, if the bias voltage is further increased or the pressing force on one photoreceptor is increased, it is possible to achieve 90% irradiation. However, the device needs to be robust, and the power supply capacity increases, which increases the cost of the device.For zero-shot V@, after performing appropriate electrostatic and physical cleaning with the cleaning roller 2, The remaining donor 7' is mechanically cleaned by sliding the elastic roller 3 on the photosensitive drum 1.

The toner remaining after cleaning with the cleaning roller of the gi is unevenly charged,
Toners of both polarities coexist, and some of them have lost their charge, making it extremely difficult to clean them with a bias application type roller. By combining the above-mentioned complex cleaning means, the photoreceptor is not damaged and cleaning can be performed in a good manner.

[Brief explanation of the drawing]

FIG. 111 is an embodiment of the present invention, and shows a schematic layout of a cleaning section for an electrophotographic photosensitive drum. 1... Photosensitive drum 2.3... Cleaning roller 4.5... Scraping blade 6... Power source for bias application 7.7'... Residual donor 8.9... For pressing Spring member 10... Protection and resistance agent Yoshimi Kuwahara

Claims (1)

[Scope of Claims] (1) A cleaning roller III for removing residual toner on the image carrier, which is rotatably provided at the Kll pressing point in the same direction when pressed against the peripheral surface of the image carrier; An elastic body is formed on the roller shaft so that a bias having a polarity opposite to that of the charge held by the residual toner can be applied.
When the cleaning roller is pressed against the image carrier layer 11 downstream of the cleaning roller, it rotates in the opposite direction at the point of contact with the image carrier. □□□) The roller cleaning device according to claim 1, wherein the cleaning rollers of said lll1-&+#+ are driven to rotate. (3) Claim 111 or 1, wherein the porous material on the surface of the second cleaning roller is made of sponge.
The cleaning device according to item 12.