JPH07248710A - Cleaning device - Google Patents

Abstract

PURPOSE:To efficiently remove residual toner from the surface of a photoreceptor drum by providing a conductive electrode member on a part of a cleaning blade composed of an insulator and applying a direct current or an alternating current or superimposingly applying the direct and alternating currents to the conductive electrode member. CONSTITUTION:After a visible image is transferred onto a recording paper, the residual toner is stuck to the surface of the photoreceptor drum 1 and discharged by an electrifying pole and a discharge lamp. Then, a switch S is turned on to apply an AC voltage to an electrode part, 83 by AC supply 84, so that a vibrating electric field is formed between the electrode part 83 and the photoreceptor drum 1 and the residual toner is scattered in the direction of the arrow from the surface of the drum 1. Further, the residual toner stuck to the surface of the photoreceptor drum 1 is removed by the top end of a cleaning blade main body 82. At this time, the AC voltage is applied to Line electrode part 83 by the AC power supply 84 and further, preferably, a DC voltage can be applied to superimpose on the AC voltage by DC power supply 85 having a polarity opposite to that of the toner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on an image carrier using a powder developer and transferring the image onto a recording paper. The present invention relates to a cleaning device that cleans.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus using an electrophotographic system, a photosensitive drum is charged, exposed and developed, and then an image is formed on the photosensitive drum by toner which is a powder developer. The image is transferred to a recording sheet by using a transfer unit, the recording sheet is separated from the surface of the photosensitive drum by a separating unit, and the image is transferred to the recording sheet. The transfer means performs transfer with a transfer electrode having a high electric charge opposite to the electric charge of the toner, and the toner is configured to be efficiently transferred to a recording sheet. Since it remains on the surface of the photosensitive drum, cleaning is performed using a cleaning blade made of an elastic material.
However, since the adhesion force of the residual toner to the surface of the photosensitive drum is strong, it is necessary to increase the pressure contact force of the tip of the cleaning blade. Although the cleaning effect can be improved by increasing the pressure contact force as described above, the cleaning blade is formed of a conductive cleaning blade and remains on the conductive cleaning blade in order to cause scratches on the photosensitive drum surface. A charge applying means for giving the same charge as that of the toner is provided nearby, and the conductive cleaning blade repels the toner and erases the charge of the toner to remove the charge from the photosensitive drum surface. A means for separating the toner to improve the cleaning effect is known (Japanese Patent Laid-Open No. 58-78182).

[0003]

As described above, the conductive cleaning blade is charged with the same electric potential as the toner,
The conductive cleaning blade can weaken the adhesion force of the toner electrostatically adhered to the surface of the photoconductor drum, but when the residual toner is removed by the electric charge of the conductive cleaning blade as described above, the residual toner is removed. Since the electric force to the toner is weak and the cleaning blade is conductive, it is difficult to control the charge, and the residual toner adhering to the surface of the photoconductor drum cannot be efficiently separated.
Therefore, the residual toner adheres to the surface of the photoconductor drum and moves to the next image forming process position, so that a good image cannot be formed due to the residual image formed by the residual toner.

Further, some toner charges have their polarities partially reversed by transfer, which makes cleaning more difficult.

The present invention has been particularly conceived in order to remedy the above-mentioned drawbacks. That is, the cleaning blade in contact with the surface of the photosensitive drum is made of an insulator, a conductive electrode member is provided on a part of the cleaning blade, and a direct current is applied to the conductive electrode member, or preferably an alternating current is applied. Alternatively, it is intended to effectively remove the residual toner from the surface of the photoconductor drum by superimposing and applying AC and DC.

[0006]

In order to achieve the above object, according to the present invention, in claim 1, after the image formed on the image carrier is transferred to a recording paper, the surface of the image carrier is cleaned by a cleaning member. In a cleaning device for cleaning by using the cleaning member, the cleaning member is composed of an insulating member that comes into contact with the surface of the image carrier and an electrode unit that applies a voltage. The voltage applied is achieved by being an alternating voltage.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram of an image forming apparatus, in which a belt electrode 2, a developing device 3, a transfer electrode 4, a separation electrode 5 and toner are sequentially arranged in a rotating direction of a photosensitive drum 1 which is an image carrier. A strip electrode 6 and a discharge lamp 7 are provided for performing reverse charge to erase charges, and a cleaning device 8 for removing the toner remaining on the surface of the photosensitive drum 1 is provided. Reference numeral 9 denotes an original, which illuminates the original 9 with an irradiation lamp 10 and causes the reflected light of the original 9 to move together with the irradiation lamp 10 and a second and third reflection mirror 12 arranged in a V shape. ， 13 more focus lens 14
The surface of the photosensitive drum 1 charged by the band electrode 2 is exposed from the fourth reflecting mirror 15 via the. The electrostatic latent image on the surface of the photosensitive drum 1 formed by the exposure is
The developing device 3 develops to form a visible image 3A by toner. The recording paper P that is fed with the visible image 3A from the other side
The transfer sheet 4 transfers the visible image 3A, and the separation electrode 5 separates the recording paper P on which the visible image 3A is transferred from the surface of the photosensitive drum 1. The separated recording paper P is a fixing device.
After passing through 16, the visible image 3A formed by the toner is fixed on the recording paper P. After the transfer of the visible image 3A is completed, the surface of the photosensitive drum 1 is charged by the belt electrode 6 to the toner, and then the surface of the photosensitive drum 1 is discharged by the discharging lamp 7 to remove the residual toner 3B. Cleaning is performed at 8. In the charging step before cleaning, the toner having a unidirectional polarity is surely applied to the toner, and a voltage is applied to the cleaning blade used in the cleaning device 8 of the present invention to easily remove the toner. In doing so, it is a preferable structure for improving the cleaning effect.

FIG. 2 shows a cleaning blade 81 of the present invention used in the cleaning device 8. The cleaning blade 81 is made of an insulating material such as urethane rubber, and has a cleaning blade body 82 that partially contacts the surface of the photosensitive drum 1, and a conductive material provided on the non-contact surface side of the cleaning blade body 82. The electrode portion 83 of the AC power source 84 or the AC power source 84
A DC power source 85 is superposed on and applied. A switch S is provided so that the AC power supply 84 or the AC power supply 84 and the DC power supply 85 can be applied in a superimposed manner.

The operation of FIG. 2 will be described next. After transferring the visible image 3A onto the recording paper P as described above, the photosensitive drum 1
The residual toner 3B is attached to the surface. The attached residual toner 3B is discharged by the strip electrode 6 and the discharge lamp 7. Next, by turning on the switch S and applying an AC voltage from the AC power supply 84 to the electrode portion 83, the electrode portion 83
An oscillating electric field is formed between the photosensitive drum 1 and the photosensitive drum 1, and the residual toner 3B is scattered from the surface of the photosensitive drum 1 in the direction of the arrow. Further, the residual toner 3B adsorbed to the surface of the photosensitive drum 1 is cleaned by the tip of the cleaning blade main body 82.

The above cleaning action may be performed only by applying an AC voltage to the electrode portion 83, but by turning on the switch S, an AC voltage is applied from the AC power source 84 to the electrode portion 83, and the AC voltage is further applied. Overlapping, preferably,
By applying a DC voltage from a DC power supply 85 having a polarity opposite to that of the toner, the oscillating electric field and the DC voltage are made to have a charge opposite to that of the residual toner 3B, and the residual toner 3B is vibrated and attracted to the electrode portion 83. By doing so, it is possible to efficiently scatter from the surface of the photosensitive drum.

The AC voltage is preferably 500 to 5 KHz, and the peak-to-peak voltage is preferably 500 to 3000V. The DC voltage of 100 to 50V is appropriate. The AC voltage is toner 3
This is a preferable condition in which B is sufficiently vibrated and discharge breakdown does not occur.

FIG. 3 shows the cleaning blade main body 82.
Contact the tip of the photoconductor drum 1 surface, and provide an electrode portion 83 on the non-contact portion of the cleaning blade main body 82.
83, or connects the DC power source 852 of negative residual toner 3B the same polarity via a switch S _1, the switch S ₁
DC power of plus polarity opposite to residual toner 3B via
Configure so that 1 can be connected.

When the residual toner 3B is cleaned by using the cleaning blade main body 82 constructed as described above, for example, when the residual toner 3B is negatively charged, the switch S _{1 is set} to the positive DC power source. 851
Are connected so as to be applied to the electrode portion 83. Therefore, the residual toner 3B flies away from the surface of the photosensitive drum 1 and is adsorbed to the electrode portion 83 before reaching the tip of the cleaning blade main body 82, and a large amount of residual toner 3B.
Of the residual toner 3B remaining on the surface of the photosensitive drum 1 is cleaned by the tip of the cleaning blade main body 82.

After a large amount of the residual toner 3B is adsorbed on the electrode portion 83, the switch S ₁ is connected so as to apply a minus DC power source 852 to the electrode portion 83. Therefore, the residual toner 3B having a negative electric charge adsorbed to the electrode portion 83 is discharged from the electrode portion 83 into the cleaning device 8. This operation is performed only for a certain period of time before or at the end of cleaning.

4 (a), (b), (c) and (d) show electrode portions 831, 832, 833, 8 provided on the cleaning blade main body 82, respectively.
34 is another embodiment of the present invention. In FIG. 4A, an insulating coating 8311 for preventing discharge is formed on the electrode portion 831. The cleaning blade main body 82 has a thickness L of 100 to 2000 μm and a width LA of the insulating coating 8311 of 50 to 2000 μm. As a result, the residual toner 3B can be efficiently adsorbed. In FIG. 4B, the electrode portion 832 is attached to the cleaning blade main body 82.
It is possible to adsorb a large amount of the residual toner 3B by extending it in the longitudinal direction. In FIG. 4C, the electrode portion 833 is bent and covered by the tip of the cleaning blade main body 82, and the exposed surface L ₁ of the tip is set to 100 to 2000 μm. With this configuration, the adsorption rate of the residual toner 3B with respect to the electrode portion 833 can be more efficiently achieved. In FIG. 4D, an electrode portion 834 made of conductive rubber or resin (epoxy or acrylic) is provided on the front side surface of the cleaning blade main body 82. With this configuration, the electrode portion 834 can be easily attached to the cleaning blade main body 82 using an adhesive agent or the like. Further, the area of the electrode portion 834 is large, and a large amount of residual toner 3B can be adsorbed.

[0016]

As described above, according to the present invention, after the visible image 3A formed by the toner is transferred onto the recording paper P, the residual toner 3B remaining on the photosensitive drum 1 is oppositely charged to the residual toner 3B. It is possible to completely remove the residual toner by adsorbing the light from the surface of the photosensitive drum 1 by the electrode portion having the above and further cleaning the surface of the photosensitive drum 1 by the cleaning blade. Therefore, the residual toner has no influence on the next charging and development, and good image formation can be performed on the photosensitive drum 1.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus.

FIG. 2 is a configuration diagram showing a cleaning device of the present invention.

FIG. 3 is a configuration diagram showing another cleaning device of the present invention.

FIG. 4 is a front view showing a cleaning blade of the present invention.

[Explanation of symbols] 1 photoconductor drum 2 band electrode 3 developing device 3A visible image 3B residual toner 4 transfer electrode 5 separation electrode 8 cleaning device 81 cleaning blade 82 cleaning blade main body 83,831,832,833,834 electrode part 84 AC power supply 85, 851, 852 DC power supply

Claims (2)

[Claims] 1. A cleaning device for cleaning the surface of an image bearing member with a cleaning member after transferring an image formed on the image bearing member to a recording paper, wherein the cleaning member is an insulating member that contacts the surface of the image bearing member. A cleaning device comprising a member and an electrode section for applying a voltage. 2. The cleaning device according to claim 1, wherein the voltage applied to the electrode portion is an AC voltage.