JPH11265136A - Cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaner which prevents image quality deterioration caused by frictional electrification. SOLUTION: A cleaner 6 is equipped with a cleaning brush 6-1 which rotates at the same speed as a photoreceptor 1 or with a certain speed difference therewith, and the cleaning blade 6-2 which is provided downstream from the brush. Transfer residual toner scraped off from the surface of the photoreceptor 1 by the cleaning blade 6-2 is collected by the cleaning brush 6-1. Here, when the voltages of an electrifier 2 and transfer device 5 are off, a relative speed between the cleaning brush 6-1 and photoreceptor 1 is set to zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device applied to an image forming apparatus utilizing an electrophotographic process, for cleaning transfer residual toner (waste toner) on a photosensitive member from the surface of the photosensitive member.

[0002]

2. Description of the Related Art In order to clean residual toner on a photoreceptor, it is widely known that a rubber-like blade is pressed against the photoreceptor to scrape off toner from the surface of the photoreceptor. No. 55-41452, etc.). Also,
In order to transport the cleaned toner, a cleaning brush is brought into contact with the photoconductor while providing a certain nip,
In addition, a cleaning brush that carries the toner cleaned by a blade from a photoreceptor by rotating the blade is also widely used (Japanese Utility Model Laid-Open No. 3-24674 and others).

A cleaning brush formed by implanting elastic fibers on the roller surface collects transfer residual toner blocked by a cleaning blade provided on the downstream side in the rotation direction of the photoconductor. I have. Here, when the photoconductor and the cleaning brush are driven to rotate in contact, the photoconductor is frictionally charged by the cleaning brush. This frictional charging has a relatively small value compared to the potential on the photosensitive member applied from the charging device, and therefore does not affect an image when a voltage is applied to the charging device.

[0004]

However, when the photosensitive member and the cleaning brush rotate without applying a voltage to the charging device, for example, at the end of image formation, etc. When the motor is forcibly stopped, the cost increases, and the gears and the like are overloaded, resulting in a short life. In this case, the photosensitive member is charged only with the potential by the frictional charging.

If the charging polarity of the photoreceptor due to the frictional charging is opposite to the polarity of the potential applied to the photoreceptor by the charging device, it is impossible to remove the charge by the discharge lamp downstream of the cleaning device. Would. Therefore,
The charging potential of the subsequent charging device is usually lower than the potential on the regular photoreceptor for forming an image. Then, for example, in an analog image forming apparatus, there is a problem that the black portion at the lowered potential on the photoconductor becomes a thin image. In addition, in the digital image forming apparatus, there is a problem that a background portion becomes a dirty image.

Further, as the relative speed of the cleaning brush and the photoconductor at the contact position increases,
Alternatively, the triboelectric potential increases as the number of rotations of the photoconductor at the end of image formation or the like increases, so that the defective image becomes noticeable.

[0007] When the cleaning brush is new, the brush is very clean (there is no attached matter such as toner).
And the contact area with the photoreceptor is large, so that the triboelectric charging with the photoreceptor becomes larger as compared with the passage of time, and the defective image becomes more remarkable.

In order to solve the above-mentioned problems and to select a material for the cleaning brush that can provide a reliable toner conveyance performance, a special material must be used.
The cost will be high.

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and provides a cleaning apparatus which can prevent image quality deterioration due to triboelectric charging while utilizing a conventionally used cleaning brush. It is intended for.

[0010]

According to one aspect of the present invention, there is provided a cleaning blade for contacting a photosensitive member and scraping off residual toner from the surface of the photosensitive member. When no voltage is applied to the charging device, at least the cleaning brush and the photosensitive member at a contact position are provided when the charging device is not provided with a cleaning brush provided upstream of the rotation direction and provided with a cleaning brush for collecting the scraped toner. The rotation speed of the cleaning brush is controlled so as to eliminate the relative speed.

According to a second aspect of the present invention, in the first aspect of the present invention, the driving of the cleaning brush is transmitted by the rotation of the photosensitive member.

According to the first aspect of the invention, when no voltage is applied to the charging device, at least the relative speed between the cleaning brush and the photosensitive member at the contact position is eliminated. The cleaning brush does not slide, and the frictional electrification of the photoconductor is eliminated. Therefore, stable image quality is always obtained.

According to the second aspect of the present invention, since the drive of the cleaning brush is transmitted by the rotation of the photosensitive member, the relative speed between the two is eliminated easily, reliably, and at low cost. .

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram around an image forming unit of the image forming apparatus. Around the drum-shaped photoconductor 1, a charging device 2, an exposure system 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged in the order of the electrophotographic process. The photoreceptor 1 is configured to rotate in the direction of arrow A (clockwise). The surface of the photoreceptor 1 is uniformly charged by the charging device 2, and then the image exposure is performed by the exposure system 3. Is formed. The electrostatic latent image is developed by the developing device 4 to form a toner image.

The transfer paper P is fed from a paper feeding device (not shown), and faces the toner image at a transfer unit. And the transfer device 5
To transfer the toner image onto the transfer paper P, and the transfer paper P is sent as it is to the fixing device (not shown), while the surface of the photoconductor 1 after the transfer is moved to a position facing the cleaning device 6, where the toner image is transferred. The transfer residual toner is cleaned.

FIG. 2 is a configuration diagram of the cleaning device.
The cleaning device 6 includes a cleaning brush 6-1, a cleaning blade 6-2, a flicker bar 6-3, a collection coil 6-4, a cleaning case 6-5, and a cleaning inlet seal 6-6. The cleaning brush 6-1 and the collection coil 6-4 are provided in the cleaning case 6.
-5, the cleaning brush 6-1 is accommodated on the photoconductor 1 side.

The cleaning blade 6-2 is mounted on the cleaning case 6-5 at the downstream side of the cleaning brush 6-1 in the photoconductor rotation direction.
The flicker bar 6-3 is attached to the cleaning case 6-5 such that the tip thereof contacts the cleaning brush 6-1. Further, the cleaning inlet seal 6-6 is provided so that the collected toner does not spill.
At the upstream end, it is attached to the end of the cleaning case 6-5.

The cleaning brush 6-1 is provided so that the brush tip is in contact with the surface of the photoreceptor 1, for example, in the direction of arrow B (counterclockwise) with a speed difference from the photoreceptor 1.
To rotate. The recovery coil 6-4 is also rotating.

Next, the cleaning operation will be described. When the toner (transfer residual toner) remaining on the photoreceptor 1 without being transferred in the transfer portion reaches the cleaning blade 6-2, the transfer residual toner is scraped off the surface of the photoreceptor 1 by the cleaning blade 6-2. It is blocked so that it does not go downstream. Then, the damped transfer residual toner is separated from the photoreceptor 1 and conveyed by the rotation of the cleaning brush 6-1. Next, the transfer residual toner conveyed from the cleaning brush 6-1 is beaten off by the flicker bar 6-3, and is transferred to the collection coil 6-4. Thereafter, the transfer residual toner is transported from the recovery coil 6-4 to a recovery tank member (not shown).

In this embodiment, the photosensitive layer of the photosensitive member 1 is made of a polycarbonate-based organic photosensitive material having extremely good charge retention, and a cleaning brush 6 is used.
The brush material in -1 is the cleaning blade 6-
Acrylic fiber suitable for reliably transferring the transfer residual toner blocked in step 2 is used. In addition, the charging device 2 is configured such that the charging polarity of the photoreceptor 1 by the charging device 2 is negative (a negative charge in the photosensitive layer is moved to ground (not shown) by irradiating light. When charged, the light does not move even when irradiated with light.) However, according to this combination, when the cleaning brush 6-1 and the photosensitive member 1 rotate at a relative speed to each other and the photosensitive member is frictionally charged, the photosensitive layer is positively charged, and an abnormal image as described above occurs. Will be done. Therefore, in the present invention, the relative speed between the photosensitive member 1 and the cleaning brush 6-1 is eliminated by the following procedure.

FIG. 3 is a flowchart of the cleaning brush rotation control according to the embodiment of the present invention. A copy button (not shown) on the image forming apparatus is pressed. The image forming process is started by an operation such as sending a print signal by a computer or the like (not shown) (S
1). Then, the final transfer sheet of the predetermined number of transfer sheets is discharged (S2). Thereafter, it is confirmed whether or not the voltage application from the charging device 2 or the transfer device 5 for applying a charge to the photoconductor 1 has been completed (S3).

When it is determined that the voltage is off, that is, the application is completed (Y in S3), the cleaning brush 6-1 and the photosensitive member 1
(S4). However, the relative speed may not be always present in the image process. For example, the relative speed is operated at a certain relative speed with respect to the photoreceptor 1 during image formation, and after the final transfer paper is discharged, May be configured to be eliminated. And
The cleaning brush 6-1 and the photoconductor 1 are stopped (S
5) The image process ends. As described above, the rotation of the cleaning brush 6-1 prevents the photosensitive member 1 from being positively charged by friction.

FIG. 4 is a perspective view showing an example of a driving mechanism of the cleaning brush. In order to rotate the cleaning brush 6-1, the cleaning brush gear 6-7 is connected to the photoconductor gear 1-1 disposed at the end of the photoconductor 1.
With such a configuration, the cleaning brush 6-1 can rotate together with the rotation of the photosensitive member 1. During the image process, the cleaning brush 6-1 may be configured to be driven by another driving source.

The cleaning device 6 of this embodiment includes a cleaning brush 6-1 that rotates at a speed difference or at a constant speed from the photosensitive member 1, and a cleaning blade 6-2 provided downstream of the cleaning brush 6-1. The transfer residual toner scraped off from the surface of the photoconductor 1 by the cleaning blade 6-2 and blocked is collected by the cleaning brush 6-1. Here, when the voltages of the charging device 2 and the transfer device 5 are off, the relative speed between the cleaning brush 6-1 and the photoconductor 1 is set to zero. By doing so, the intended purpose can be achieved.

[0025]

According to the first aspect of the present invention, when no voltage is applied to the charging device, at least the relative speed between the cleaning brush and the photosensitive member at the contact position is eliminated. The cleaning brush does not slide on the body, frictional charging of the photoconductor is eliminated, and stable image quality can be always obtained.

According to the second aspect of the present invention, since the drive of the cleaning brush is transmitted by the rotation of the photosensitive member, the cleaning brush can be easily, reliably and at low cost.
The relative speed between the two can be eliminated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram around an image forming unit of an image forming apparatus.

FIG. 2 is a configuration diagram of a cleaning device.

FIG. 3 is a flowchart of cleaning brush rotation control according to the embodiment of the present invention.

FIG. 4 is a perspective view showing an example of a cleaning brush driving mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 charging device 3 exposure system 4 developing device 5 transfer device 6 cleaning device 6-1 cleaning brush 6-2 cleaning blade 6-3 flicker bar 6-4 recovery coil 6-5 cleaning case 6-6 cleaning inlet seal 6 -7 Cleaning brush gear

Claims (2)

[Claims] A cleaning brush provided in contact with the photoreceptor to scrape off transfer residual toner from the surface of the photoreceptor; and a cleaning brush provided upstream of the cleaning blade in the rotation direction of the photoreceptor for collecting the scraped-off toner. In the provided cleaning device, at least when no voltage is applied to the charging device,
A cleaning device wherein the rotation speed of the cleaning brush is controlled so as to eliminate the relative speed of the cleaning brush and the photoconductor at the contact position. 2. The cleaning device according to claim 1, wherein the drive of the cleaning brush is transmitted by rotation of a photoconductor.