JPS63221376A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To remove a remaining magnetic toner from a photosensitive body without generating flaws, wear, etc., on said body by applying a bias voltage to the conductive fur body of a cleaning brush, bringing the brush into pressurized contact with the surface of the photosensitive body and bringing a recovering roller applied with a bias voltage into contact with this cleaning brush. CONSTITUTION:The untransferred magnetic toner remaining on the surface of the org. photosensitive drum 10 after the end of a transfer stage is rubbed by the cleaning brush 21. The bias voltage is applied by a power supply 26 to the conductive fur body 28 of the cleaning brush 21 and the toner is attracted to the conductive fur body 28 side. The bias voltage is applied by a power supply 27 to the recovering roller 22 which rotates by maintaining the pressurized contact with the cleaning brush 21, by which the electrostatic attraction force overcoming the attraction force from the conductive fur body 28 is acted on the toner attracted to the conductive fur body 28 of the cleaning brush 21 and the toner is recovered. The recovered toner is scraped by a blade 23 and is dropped onto a transfer screw 25.

Description

[Detailed description of the invention] [Industrial application field]

This invention exists! The present invention relates to an image forming apparatus and a cleaning apparatus that attach magnetic toner to an electrostatic latent image formed on the surface of a photoreceptor to create a visible image.

Background of the Invention Generally, in an image forming apparatus such as a transfer type electrophotographic copying machine, a rotating drum type photoreceptor having a photoconductive photosensitive layer on the outer peripheral surface is used, and while the photoreceptor is rotated, the photosensitive layer is An electrostatic latent image is formed on the recording paper, developed with toner, and the resulting toner image is transferred to recording paper. After the transfer is completed, the residual toner on the outer circumferential surface of the photoreceptor is removed and cleaned by a cleaning device, an e-electronic latent image is formed again, and a new image is transferred. In recent years, an electrostatic latent image is formed on a photoreceptor having an organic photoconductive compound layer on its surface, and a magnetic toner is attached as a developer to this electrostatic latent image to form a visible image. Image-type R&Vt systems have come into use in which images are transferred to recording paper. In such an image forming apparatus, untransferred residual toner is removed from the photoreceptor by a commonly used cleaning device. Examples of such cleaning devices include those using a blade cleaning method and those using a high-speed rotating brush cleaning method. The blade cleaning method uses a soft blade member such as urethane rubber as a cleaning means. This blade member is brought into strong pressure contact with the surface of the photoreceptor, and while rubbing, the adhering toner is forcibly peeled off by the operation of the blade member. The peeled toner becomes powder or lumps and falls along the surface of the photoreceptor. The fallen toner is collected by the toner receiver member. In the high-speed rotating brush cleaning method, a brush in which insulating bristles are implanted on the circumferential surface of a cylindrical bristles holding member is used as a cleaning means. Then, while rotating this brush at high speed, a part of the brush is brought into contact with the photoreceptor, and the attached toner is rubbed and removed. The removed toner is energized by the high-speed rotation of the brush, and becomes fine powder and scatters around the photoreceptor. Scattered toner is sucked and collected by powerful saccilane means. [Problems to be Solved by the Invention] However, even if these cleaning methods are adopted for the purpose of removing the magnetic toner remaining on the surface of the organic photoreceptor, it is difficult to maintain the image quality of the photoreceptor, the durability of the photoreceptor, etc. Q% does not necessarily give satisfactory results. For example, in the case of the blade cleaning method, when the blade strongly presses and rubs the photoreceptor, the rubbing action of the blade may create impressions on the organic photoreceptor layer on the surface of the photoreceptor, or accelerate abrasion of the organic photoreceptor layer. This shortens the life of the photoreceptor. In addition, since this blade rubs the photoreceptor with magnetic toner containing iron powder interposed between its two prongs, it causes streak-like scratches on the surface, and these scratches degrade the image quality of the photoreceptor. Sometimes. On the other hand, in the case of the high-speed rotating brush cleaning method, a high-speed rotating insulated brush is brought into contact with the surface of the photoconductor to rub and remove residual magnetic toner on the surface of the photoconductor, so the toner becomes fine powder and is scattered around the photoconductor. Float. In order to collect this scattered/floating toner, a powerful and large-scale cleaning method is required. Furthermore, when a photoreceptor is rubbed at high speed with magnetic toner containing iron powder attached to the surface of the insulating brush, streak-like scratches may occur on the surface of the photoreceptor. These scratches degrade the image quality of the photoreceptor. Further, the polishing action causes the RitI+ optical layer on the surface of the photoreceptor to be worn away, shortening the life of the photoreceptor. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to remove magnetic toner remaining on the surface of an organic photoreceptor after transfer without causing scratches, wear, etc. on the photoreceptor. It is an object of the present invention to provide a cleaning device for a WI image forming apparatus that is capable of performing the following steps.

[Means for Solving the Problems 1] The above object is to form an electrostatic latent image by irradiating image light onto a photoreceptor having an organic photoconductive compound layer on its surface, and to apply magnetic toner to the electrostatic latent image. In a cleaning device for an image forming apparatus, the cleaning device transfers a visible image of a hind limb to form a visible image and removes the magnetic toner remaining on the photoreceptor after the transfer, the cleaning device A bias voltage is applied to the conductive hairs implanted on the surface, and the hairs are pressed together.
a cleaning brush that rotates to rub and remove residual toner on the surface of the photoconductor; and a collection roller that applies a bias voltage to a conductive cylinder and contacts and rotates the cleaning brush to collect the toner on the cleaning brush. This is achieved by a cleaning device for an image forming apparatus characterized by comprising: [Example] An example of the present invention is shown in FIG. Shown in Figure 152. First, the general functions of the image forming apparatus will be explained with reference to FIG. ff12. In the tlS2 diagram, A is a scanning exposure section, B is an image forming section, C is a paper feeding section, D is a fixing section, E is a paper discharging section, and 20 is a cleaning device according to the present invention. In the scanning exposure section, 1 is a platen plus, and the original is placed on this platen plus 1. The original is illuminated by a movably mounted light source 2, the light image of the original on the platen glass 1 being transmitted by a mirror 3.4.5 to a lens 6 where it is focused. Focused light is reflected I! 7
The organic photoreceptor drum 10, which serves as an image carrier, has its optical path bent by
is projected onto the surface of the object to form an emission line. The focused light is uniformly charged in advance by a charger 8 and projected onto a rotating organic photoreceptor drum 10. By projecting the focused light, a latent image corresponding to the original image is formed on the surface of the photoreceptor. The latent image is formed in the developing device 1 loaded with magnetic toner in the image forming section B.
1 to form a toner image on the surface of the organic photoreceptor. The toner image developed in this manner is sent by a feeding roller from a paper feeding section C and is transferred onto a recording paper, which is a general transfer body, at a transfer pole 12. The recording paper onto which the toner image has been transferred is separated from the organic photoreceptor drum 10 by Ni 13. The separated recording paper is conveyed to the fixing section and fixed thereon, and then discharged from the wandering paper section E to the outside of the machine. to obtain a copy of the original. On the other hand, the organic photoreceptor drum 10 separated from the transfer paper by the separation electrode 13 enters the cleaning device RA20 according to the present invention carrying unprinted residual toner. At this point, the residual toner on the organic photoreceptor drum 10 is removed and a new copy cycle is started (prepared). This photosensitive layer is further composed of a laminate of a carrier generation layer containing a carrier generation substance and a carrier transport layer containing a carrier transport substance. The photosensitive layer is formed by dispersing a photoconductive compound such as a 7zo compound or a bisazo compound in a binder and coating it on the surface of a conductive support. The developer used is a one-component magnetic toner mainly composed of iron powder and toner. Figure W&1 is a cross-sectional view of the cleaning device of the present invention. Cleaning The device 20 includes a cleaning brush 21, a collection roller 22, a blade 23, a toner suction means 24, a conveyance screw 25, a first bias voltage 't4@26, a second bias voltage power source 27, etc., and is mounted inside a frame 30. The cleaning brush 21 is a cylindrical brush in which conductive bristles 28 are connected to a conductive pipe made of aluminum or the like with a base fabric using a conductive adhesive.The conductive bristles 28 are made of a base fabric. The conductive fibers 28 are woven in a so-called W weave to increase the contact area with the conductive pipe.The density of the conductive bristles 28 on the pipe is between too, ooo and 200,000 filaments/filament. in2. The conductive hair body 28 is composed of conductive rayon [RecGRJ or [RecARJ (Unitika Co., Ltd. 91)]. Conductive rayon r: RecGRJ has a fiber specific resistance of 108
~10''Ωe1m, and JRecARJ has a fiber specific resistance of 10'~10''96m. The cleaning brush in this example has a length of 5 to 10 mm.
, a conductive hair body with a thickness of 5 to 6 deniers was used. FIG. 3 shows a method for measuring am specific resistance. In Figure 3, 50 is a fiber resistivity measurement circuit, P and Q are electrodes, and 5
1 is a fiber to be measured, 52 is a 500VW 1-voltage power source, and 53 is an ammeter. The specific resistance of the fiber to be measured 51 is measured as follows. First, a filament-shaped fiber to be measured 51 is placed on the electrode P and the electrode Q.
The distance l between the two electrodes connecting the two electrodes is 10 cm. A voltage of 500 V is applied between the electrodes P and Q by the voltage power source 52, and the current value flowing at that time is ■. is read from the ammeter 53. The specific resistance ρ of the fiber 51 to be measured is calculated from the following equation. ρ, 500/r. -S/1 Note that S is the total cross-sectional area of the line to be measured R51, which is the product of the thickness and number of fibers. The cleaning brush 21 is installed in pressure contact with the drum at a position slightly away from the separation electrode 13 toward the downstream side of the photoreceptor drum. The cleaning brush 21 is in a state in which the brushes 21 and 21 overlap each other in the radial direction.A bias voltage of DC zoov is applied to the cleaning brush 21 by the first bias voltage power supply 26.The recovery row 222 is made of a conductive metal. The recovery row 222 is a roller.The recovery row 222 is installed in a position separated from the pressure contact portion between the cleaning brush 21 and the organic photoreceptor drum 10 toward the downstream side in the direction of rotation of the brush, and is in pressure contact with the brush.This pressure contact state The collection a-ra 22 and the cleaning brush 2
1 and 2 to 4III* overlap each other in the radial direction. A bias voltage of 400 V DC is applied to the recovery roller 22 by a second bias voltage power source 27 . The blade 23 is an elastic plate made of urethane rubber or the like. The blades 23 are in pressure contact with each other along the entire length of the collecting roller 22 in the longitudinal direction, and scrape off the toner from the surface of the roller. The toner suction means 24 includes an electric suction unit 241 and a filter 242. This toner suction means 24
The suction opening of the cleaning brush 21 and collection roller 2
The brush 21 is provided near the pressure contact portion with the brush 21 and facing the downstream portion of the brush 21 in the rotational direction. The conveyance screw 25 is provided near the bottom of the blade 23 and conveys the toner scraped off from the collection roller 22 to a toner collection tank (not shown). The cleaning device of the present invention has the above-described configuration, and its operation will be described below. After the transfer process is completed, the organic photoreceptor drum 10 remains untransferred.
The untransferred magnetic toner remaining on the outer peripheral surface of the organic photoreceptor drum 10 is rubbed by the cleaning brush 21 of the cleaning device fi20 as the organic photoreceptor drum 10 rotates in the direction of the arrow. At this time, the linear velocity of the outer peripheral surface of the organic photoreceptor drum 10 is 20
0-so/sec. And cleaning brush 2
The linear velocities of the organic photoreceptor drum 1 and the organic photoreceptor drum 10 are the same, and the directions of rotation are opposite. Therefore, the residual magnetic toner on the organic photoreceptor drum 10 is rubbed by the cleaning brush 21 at a sliding speed of 400 sta/sec. The conductive bristles 28 of the cleaning brush 21 are at the first bias voltage? ! A bias voltage of 200 V DC is applied by i'g2s, and the residual magnetic toner is charged with a polarity opposite to that of the residual magnetic toner. The conductive bristles 28 apply electrostatic attraction to the residual magnetic toner, causing the toner to be attracted to the conductive upper layer and removed from the outer peripheral surface of the organic photoreceptor drum 10. The toner adsorbed to the conductive bristles 28 of the cleaning brush 21 is then collected by a collection roller 22 that rotates while being in pressure contact with the cleaning brush 21. The cleaning brush 21 and the collecting roller 22 have the same linear velocity near their outer circumferential surfaces, and their rotating directions at the contact portion are opposite. Therefore, the collection roller 22
The adsorbed toner of No. 1 is rubbed at a rubbing speed of 400 mm/sec. A bias voltage of 400 volts DC is applied to the collection roller 22 by a second bias voltage power source, and the collection roller 22 is charged with a polarity opposite to that of the toner. The collection a-ra 22 collects the toner in the cleaning brush 21 by applying an electrostatic attraction force that is stronger than the attraction force from the conductive bristles 28 to the toner. Then, the toner collected on the collection row 222 is scraped off from the surface of the roller by the blade 23 and falls onto the conveyance screw 25. On the other hand, the cleaning brush 21 gets into the bristles 1
? 712k 41k l-+-/F'l-Makoto1-)
Fn 1Iff M-49') l-r? I 1
lff R's cleaning brush has remained since February. The conductive bristles 2 are located downstream in the rotational direction of the cleaning brush 21 and the collection roller 22 in the vicinity of their contact area.
8 is released from the pressure of the collection roller 22 and returns from the fallen state to the standing state. Unrecovered magnetic toner is separated from the cleaning brush 21 by the repulsive force and centrifugal force when returning to the raised state, and is scattered into the air. The scattered toner is collected by suction by a toner suction means 24, which has suction openings facing each other in the vicinity of the toner removal portion. In this embodiment, a case where an image is formed using a monochromatic developer has been described, but the present invention can also be applied to a case where a color image is formed by combining monochromes. To form a color image, a plurality of developing units are arranged around the periphery of the photoreceptor, and one color is developed in a non-contact manner each time the photoreceptor rotates. After a plurality of rotations, a color toner image is formed on the photoreceptor. Therefore, during the formation of a color toner image,
The cleaning member must be spaced apart from the photoreceptor. By providing the cleaning device of this embodiment with pressure contact and pressure release means for the photoreceptor drum, color image formation is possible.
tcf! It can also be applied to In particular, when the organic photoreceptor is constructed of a laminate in which the surface layer of the photosensitive layer is provided with a carrier generation layer and a carrier transport layer underneath, wear of the carrier generation layer is noticeable during cleaning using the conventional method. However, by using the cleaning device of the present invention, these problems can be reduced. Effects of the Invention In the cleaning device for an image forming apparatus of the present invention, as explained in the embodiment, the sliding action of the conductive brush on the organic photoreceptor drum is different from the sliding action of the conventional high-speed rotating brush cleaning method. This is done at a very slow speed compared to the f1 operation. Since the conductive brush is rotated at a low speed and the toner is deposited exclusively by electrostatic attraction, it is possible to significantly reduce the load on the surface of the organic photoreceptor. In this way, when cleaning the magnetic toner remaining on the surface of the organic photoreceptor, it is possible to remove scratches on the surface of the organic photoreceptor.
It has become possible to avoid the occurrence of impressions, etc., and it has become possible to maintain the image quality of the organic photoreceptor in a good state. In addition, we have eliminated causes of wear on the organic photosensitive layer, such as pressure and rubbing of the blade member and high-speed rubbing of the insulating brush.
It has now become possible to provide a cleaning device for an image forming apparatus that has a remarkable effect on improving the life of an organic photoreceptor.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention for cleaning! lr!
1 is a sectional view, FIG. 2 is a configuration diagram of an image forming apparatus, and FIG. 3 is a circuit diagram showing a method for measuring fiber specific resistance. 10...Organic photoreceptor drum 11...Developer 13...Minute #
L pole 20...Cleaning device 21...Cleaning brush 22...Collection roller 23...Blade 24...Toner suction means 25... ...Conveyance screier 26...First bias voltage power supply 27...
・Second bias voltage power supply 28... Conductive hair body
30... Frame applicant Konishiroku Photo Industry Co., Ltd. Figure 3

Claims (1)

[Claims] A photoreceptor having an organic photoconductive compound layer on its surface is irradiated with image light to form an electrostatic latent image, and a magnetic toner is attached to the electrostatic latent image to form a visible image. transfer the image,
In a cleaning device for an image forming apparatus that removes the magnetic toner remaining on the photoreceptor after transfer, the cleaning device applies a bias voltage to conductive bristles implanted on the circumferential surface of the cylindrical body. A cleaning brush that rubs and removes residual toner on the surface of the photoreceptor by pressing and rotating its bristles, and a conductive cylindrical body that applies a bias voltage and contacts and rotates the cleaning brush to remove the toner on the cleaning brush. 1. A cleaning device for an image forming apparatus, comprising: a collection roller for collecting images.