JPH04336582A - Cleaning roller device for electrophotographic device - Google Patents

Abstract

PURPOSE:To enable magnetic powder such as a carrier in developer to be adsorbed and removed with magnetic force even upon occurrence of a drop in adhesive strength due to deposition of a foreign substance on an adhesive section, the occurrence of a void image section to be substantially decreased, and further enable a cleaning frequency for the surface of a cleaning roller and service cost to be reduced. CONSTITUTION:A cleaning roller 37 has double construction internally. A roller core section 37a is constituted of ferrite magnet and an adhesive section 37b of adhesive rubber material is formed on the surface of the roller core section 37a. The cleaning roller 37 is pressed to be in contact with the second photosensitive body drive roller 6 with spring members 39 and 39 fitted to cleaning roller shafts 38 and 38 projected from both axial ends. Furthermore, the cleaning roller 37 rotates following the second photosensitive body drive roller 6, and removes a foreign substance such as developer adhering to the peripheral surface of the second photosensitive body drive roller 6, using adhesive strength and magnetic force.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to the use of waste particles such as developer and beads for preventing meandering of the photoreceptor that adhere to the back surface of a belt-shaped photoreceptor or the circumferential surface of the photoreceptor driving roller that drives the photoreceptor. The present invention relates to a cleaning roller device for an electrophotographic apparatus that removes foreign matter.

0002

2. Description of the Related Art As shown in FIG. 5, a full-color copying machine using an electrophotographic method includes a belt-shaped photoreceptor (
In some cases, a photosensitive belt (hereinafter referred to as a photosensitive belt) 54 is used.

In the above-mentioned full-color copying machine, the optical scanning section 52a, which includes an irradiation lamp and a reflecting mirror, is connected to the original table 51.
The original 53 placed thereon is optically scanned. As a result, the reflected light from the original 53 is filtered by the color separation filter 52d.
The light is sequentially separated into red, green, and blue color components, and is irradiated onto the photoreceptor belt 54, which is uniformly charged by the charger 68. As a result, electrostatic latent images for each color component corresponding to the image of the original document 53 are sequentially formed on the photoreceptor belt 54 .

Above the photoreceptor belt 54, in a non-contact state with the photoreceptor belt 54, there are developer tanks 59 to 6 containing yellow, magenta, cyan, and black developers.
2 are arranged. The developer is supplied to the photoreceptor belt 54
A toner (diameter 10 μm) that develops the electrostatic latent image formed on the
The carrier is composed of a metal powder such as iron or ferrite whose surface is coated with silicone resin, fluoropolymer resin, etc., and is used to transport the toner. Each electrostatic latent image formed on the photoreceptor belt 54 is developed and visualized with each developer at a portion facing the developing tanks 59 to 62, and becomes a toner image.

[0005] Also, one side of a transfer belt 74 is pressed against the second photoreceptor driving roller 56 side of the photoreceptor belt, and the toner images for each color component are transferred to the photoreceptor belt 24 when the photoreceptor belt 24 is pressed against it. The images are sequentially transferred onto the transfer belt 74 by primary transfer rollers 78 and 79 provided on the back side of the transfer belt 74 at the portions where the images are transferred. In this manner, toner images for each color component are transferred from the photoreceptor belt 54 to the transfer belt 74 and sequentially overlapped, so that a full-color toner image is formed on the transfer belt 74.

[0006] When the toner image is transferred from the photoreceptor belt 54 to the transfer belt 74, if foreign matter 71 is attached to the back surface of the photoreceptor belt 54 or the circumferential surface of the second photoreceptor driving roller 56, as shown in FIG. As shown in FIG. 6, it is known from experience that the toner image 72 in the area to which the foreign matter 71 has adhered is not transferred to the transfer belt 74, resulting in white missing areas (hereinafter referred to as missing white areas) on the copy. There is.

The above-mentioned foreign matter 71 includes the developer of each color mentioned above and the dregs of a bead for preventing meandering of the photoreceptor belt made of rubber, but the size of the foreign matter 71 causes the white spots. It is also known that it is carrier or bead residue in the developer with a size of about several hundred micrometers.

[0008] When the above-mentioned white spots occur in large numbers, the copy image quality is significantly impaired, so in conventional copying machines, ethylene propylene rubber (EPDM) or nitrile rubber (N
The cleaning rollers 57 and 58 are made of adhesive rubber material mixed with tackifier (BR) and wound around a stainless steel core.
By press-contacting the second photoreceptor drive roller 56 and the back surface of the photoreceptor belt 54 and rotating them in a driven manner, foreign matter 71 attached to the back surface of the photoreceptor belt 54 and the circumferential surface of the second photoreceptor drive roller 56 is removed. is removed by adsorption to the surfaces of cleaning rollers 57 and 58.

[0009]

However, in the conventional configuration described above, the foreign matter 71 is removed only by the adhesive force of the adhesive rubber material, so if the foreign matter 71 adheres to the surface of the cleaning rollers 57 and 58, the cleaning roller 57.5
The problem is that the foreign matter removal ability of No. 8 is drastically reduced and white spots are likely to occur.

In addition, in order to restore the foreign matter removal ability of the cleaning rollers 57 and 58, the cleaning roller 57 is
・Since it is necessary to frequently clean the 58 surface, there is also the problem that the service cost increases.

The present invention has been made in view of the above, and its object is to prevent the foreign matter removal ability from suddenly decreasing even if foreign matter adheres to the surface of the cleaning roller, and to reduce the occurrence of white spots. Another object of the present invention is to provide a cleaning roller device for an electrophotographic apparatus that can reduce service costs.

0012

[Means for Solving the Problems] In order to solve the above-mentioned problems, the cleaning roller device for an electrophotographic apparatus of the present invention has a cleaning roller device that is pressed against the back surface of a belt-shaped photoreceptor and adheres to the back surface of the photoreceptor while being driven. A cleaning roller having an adhesive portion formed on its surface, which removes foreign matter or adheres to the circumferential surface of the photoconductor drive roller while being pressed against and driven by the photoconductor drive roller that drives the photoconductor. In the cleaning roller device equipped with this, the following measures are taken.

That is, the cleaning roller has a magnetic field generating means in the roller core.

[0014]

[Operation] According to the above structure, the cleaning roller device includes a cleaning roller having an adhesive portion formed on its surface and further having a magnetic field generating means in the roller core. The cleaning roller is provided on the back side of a belt-shaped photoreceptor or in pressure contact with a photoreceptor drive roller that drives the photoreceptor, and rotates as the photoreceptor is rotationally driven by the photoreceptor drive roller. .

At this time, the cleaning roller removes, for example, developer attached to the back surface of the photoreceptor or the circumferential surface of the photoreceptor driving roller due to the adhesive force of the adhesive portion formed on the surface and the magnetic force of the magnetic field generating means. Remove foreign matter such as scum from the bead for preventing meandering of the photoreceptor belt, which is made of rubber.

Therefore, even if foreign matter adheres to the adhesive part of the cleaning roller and the ability to remove foreign matter due to the adhesive force of the adhesive part decreases, the magnetic force of the magnetic field generating means will remove magnetic powder such as carrier in the developer. is absorbed by the cleaning roller. In particular, carriers in the developer with a size of several tens to hundreds of micrometers cause white spots, but as described above, the cleaning roller does not remove foreign matter even if it adheres to the adhesive surface. Since it always maintains carrier removal ability above a certain level, the occurrence of white spots can be significantly reduced compared to conventional methods.

[0017] Furthermore, as described above, even if foreign matter adheres to the adhesive part of the cleaning roller, the foreign matter removal ability does not suddenly decrease, so the number of times the cleaning roller surface is cleaned can be significantly reduced compared to the conventional method. .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

As shown in FIG. 4, the full-color copying machine as an electrophotographic apparatus of this embodiment has a transparent original placing table 1 on the upper surface, and an exposure optical system is provided below the original placing table 1. System 2 is installed. The exposure optical system 2 has a light scanning section 2a that includes an irradiation lamp and a reflecting mirror that irradiates light onto the original 3 placed on the original placing table 1.

The exposure optical system 2 also includes the above-mentioned optical scanning section 2.
In addition to a, a plurality of reflecting mirrors 2b are arranged on the optical path to guide the reflected light from the original 3 onto a belt-shaped photoreceptor (hereinafter referred to as photoreceptor belt) 4, as shown by the dashed line, for example. It includes an imaging lens 2c that forms an optical image reflected from the original 3 onto the photoreceptor belt 4, and a color separation filter 2d having color filters for three primary colors (red, green, and blue).

Further, below the exposure optical system 2, there is a developing device 13 having four developing tanks 9 to 12, the above-mentioned photosensitive belt 4, and two paper feed cassettes 21 and 22 according to size.
and is provided. Furthermore, a transfer device 14, a conveyance belt 15, and a fixing device 16 are arranged in this order on the side of the photoreceptor belt 4 in the paper output direction, and a discharge roller 17 is provided at the paper output section 23.

The photoreceptor belt 4 is rotationally driven by first and second photoreceptor drive rollers 5 and 6 as photoreceptor drive belts. A cleaning roller device 8, which will be described later, is provided on the back surface of the photoreceptor belt 4 near the second photoreceptor driving roller 6. Further, a cleaning roller device 7, which will be described later, is provided at a position on the second photoreceptor driving roller 6 that does not slide on the photoreceptor belt 4.

Further, on the outer periphery of the photoreceptor belt 4, a charger 18 for charging the photoreceptor belt 4 is located near the first roller 5 on the side where the reflected light from the exposure optical system 2 is irradiated. It is arranged. In addition, the photoreceptor belt 4
A cleaning device 19 for removing toner remaining on the photoreceptor belt 4 is disposed below the photoreceptor belt 4 .

Further, the above-mentioned developing device 13 is disposed near the center above the photoreceptor belt 4 in a non-contact state with the photoreceptor belt 4, and includes three color developing tanks 9.
11 contain yellow, magenta, and cyan color developers, and the black developer tank 12 contains a developer containing a black pigment such as carbon black. The developer includes toner of each color (resin powder with a diameter of about 10 μm) for developing the electrostatic latent image formed on the photoreceptor belt 4, and metal powder such as iron or ferrite for transporting the toner. It consists of a carrier whose surface is coated with silicone resin, fluoropolymer resin, etc.

On the other hand, the transfer device 14 has a transfer belt 24.
This transfer belt 24 has three rollers 2
5 to 27 to rotate. The second photoreceptor drive roller 6 side of the photoreceptor belt 4 is in pressure contact with one side of the transfer belt 24, and a primary Transfer rollers 28 and 29 and a secondary transfer roller 30 are arranged on the lower surface side of the transfer belt 24, respectively.

Further, paper feed rollers 31 and 32 are provided on the paper output sides of the paper feed cassettes 21 and 22, respectively, and transport rollers 33 and 32 are provided in the paper feeding direction of the paper feed rollers 31 and 32, respectively. 34 are provided. Furthermore, a timing roller 35 is provided in the paper feeding direction of the conveyance roller 34. Further, above the paper feed cassette 21, a manual paper feed section 36 having a paper input roller 37 is provided.

Here, the cleaning roller device 7.
8 will be explained in detail below.

The cleaning roller device 7 has a cleaning roller 37, as shown in FIG. Cleaning roller shafts 38, 38 are protruded from both ends of the cleaning roller 37, and are supported by bearings (not shown). And the cleaning roller shaft 38.3
8 is provided with spring members 39 for pressing the cleaning roller 37 against the second photoreceptor driving roller 6.

The cleaning roller device 8 has a cleaning roller 40, as shown in FIG. Cleaning roller shafts 41 are protruded from both ends of the cleaning roller 40 and are supported by bearings (not shown). The cleaning roller shafts 41 and 4
1 is provided with spring members 42 that press the cleaning roller 40 into contact with the back surface of the photoreceptor belt 4.

As shown in FIG. 3, the cleaning roller 37 has a double structure inside, and a ferrite magnet serving as a magnetic field generating means constitutes a roller core 37a.
An adhesive portion 37b is formed on the surface of the roller core portion 37a. The adhesive portion 37b includes a second photoreceptor driving roller 6.
In order to increase the nip width of the contact area, a low hardness adhesive rubber material made of ethylene propylene rubber (EPDM) or nitrile rubber (NBR) mixed with a tackifier is used. That is, the cleaning roller 37 is formed by winding an adhesive rubber material around a cylindrical ferrite magnet.

Further, the cleaning roller 40 has the same structure as the cleaning roller 37 (see the same figure).

The operation of the present full color copying machine with the above configuration will be explained.

First, as shown in FIG. 4, while the original 3 placed on the original placing table 1 is irradiated with light from the irradiation lamp, optical scanning is performed three times by the optical scanning section 2a. At this time, if you want to reproduce black text or line drawings particularly clearly,
One more optical scan is performed.

As a result, the reflected light from the original 3 enters the color separation filter 2d via the reflecting mirrors 2b, and is separated into color components by the color separation filter 2d. The light for each color component for each light scan is further irradiated onto the photoreceptor belt 4, which is uniformly charged by the charger 18, via the imaging lens 2c and the reflecting mirrors 2b. is exposed. As a result, electrostatic latent images for each color component corresponding to the image of the original 3 are sequentially formed on the photoreceptor belt 4.

Each of the electrostatic latent images described above is formed by the developing device 13 at a portion of the color separation filter 2d facing the developing tanks 9 to 11 containing developers of yellow, magenta, and cyan, which are complementary colors of each color filter. At this time, the toner image is developed with each developer, and further developed and visualized as needed in a portion facing the developer tank 12 containing a black developer to form a toner image. These toner images for each color component are transferred to a primary transfer roller 2 in a transfer device 14.
8 and 29, the images are sequentially transferred to the transfer belt 24. In this way, a full-color toner image is formed on the transfer belt 24 by sequentially overlapping the toner images for each color component.

On the other hand, transfer paper (not shown) is sent out from the paper cassettes 21 and 22 to the transport path by paper feed rollers 31 and 32, or from the manual paper feed section 36 and sent to the transport path by the paper input roller 37. , transport rollers 33 and 34
is conveyed to the timing roller 35. Then, the transfer paper is sent to the second transfer roller 30 by the timing roller 35 at a predetermined timing, and the toner image is transferred onto the transfer paper by the second transfer roller 30. After the transfer, the transfer paper is transferred to the fixing device 16 via the conveyor belt 15.
The image transferred to the transfer paper is heated and fixed by the fixing device 16 to form a full-color copy image. Thereafter, the transfer paper is discharged from the paper output section 23 to the outside of the machine by the discharge roller 17.

Next, the operation of the cleaning roller devices 7 and 8 will be explained.

As shown in FIG. 1, the cleaning roller 37 of the cleaning roller device 7 rotates as the second photoreceptor driving roller 6 rotates. At this time, the cleaning roller 37 removes the developer attached to the circumferential surface of the second photoreceptor driving roller 6 due to the adhesive force of the adhesive portion 37b formed on the surface and the magnetic force of the roller core portion 37a made of a ferrite magnet. Remove foreign matter such as scum from the bead for preventing meandering of the photoreceptor belt, which is made of rubber.

Further, as shown in FIG. 2, the cleaning roller 40 of the cleaning roller device 8 is driven to rotate when the photoreceptor belt 4 is driven. At this time, the cleaning roller 40 removes the foreign matter adhering to the back surface of the photoreceptor belt 4 using the adhesive force of the adhesive portion 40b and the magnetic force of the roller core portion 40a made of a ferrite magnet.

For this reason, the present cleaning roller device 7.
In No. 8, foreign matter adheres to the surfaces of the adhesive parts 37b and 40b of the cleaning rollers 37 and 40, and the adhesive parts 37b and 40b are damaged.
Even if the ability to remove foreign matter due to the adhesive force of roller 40b is reduced, magnetic powder such as carrier in the developer is attracted to cleaning rollers 37 and 40 by the magnetic force of roller cores 37a and 40a made of ferrite magnets. In particular, carriers in the developer with a size of several tens to hundreds of micrometers cause white spots, but this cleaning roller 37
As mentioned above, even if foreign matter adheres to the surfaces of the adhesive parts 37b and 40b, 40 always maintains a certain level of carrier removal ability, so the occurrence of white spots can be significantly reduced compared to the conventional method. .

Furthermore, the present cleaning roller devices 7 and 8
Unlike the conventional method, even if foreign matter adheres to the surfaces of the adhesive parts 37b and 40b, the foreign matter removal ability does not deteriorate suddenly.
The number of times the cleaning rollers 37 and 40 are cleaned can be significantly reduced compared to the conventional method, and service costs can be reduced.

In this embodiment, the photoreceptor belt 4
Although only one cleaning roller device 8 is provided on the back surface of the photoreceptor belt 4, a plurality of cleaning roller devices may be provided on the back surface of the photoreceptor belt 4. Furthermore, not only the second photoreceptor driving roller 6 but also the first photoreceptor driving roller 5 may be provided with a cleaning roller device.

Further, in this embodiment, ferrite magnets are used as magnetic field generating means in the roller core portions 37a and 40a of the cleaning rollers 37 and 40.
For example, silicon steel with high magnetic permeability is formed into a cylindrical shape and a coil is wound around the circumferential surface as the roller core, and the first and second photoreceptor driving rollers 5 - While the photoreceptor belt 4 is rotationally driven by 6, the coil may be energized to generate magnetic force.

[0044]

As described above, the cleaning roller device for an electrophotographic apparatus according to the present invention has a magnetic field generating means in the roller core of the cleaning roller.

Therefore, even if foreign matter adheres to the adhesive part of the cleaning roller and the ability to remove foreign matter due to the adhesive force of the adhesive part decreases, the magnetic force of the magnetic field generating means will remove the foreign matter in the developer that causes white spots. Magnetic powder such as carrier is attracted to the cleaning roller. In other words, the cleaning roller always maintains a certain level of carrier removal ability even if foreign matter adheres to the surface of the adhesive part, so it has the effect of greatly reducing the occurrence of white spots compared to the conventional method. .

[0046] Furthermore, as described above, even if foreign matter adheres to the adhesive part of the cleaning roller, the ability to remove foreign matter does not suddenly decrease, so the number of times the cleaning roller surface is cleaned can be significantly reduced compared to the conventional method. This also has the effect of reducing service costs.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a schematic perspective view showing a cleaning roller device provided on a second photoreceptor driving roller in an electrophotographic apparatus.

FIG. 2 is a schematic perspective view showing a cleaning roller device provided on the back side of a belt-shaped photoreceptor in the electrophotographic apparatus.

FIG. 3 is a schematic partial cross-sectional perspective view of the cleaning roller.

FIG. 4 is an overall configuration diagram showing main parts of the electrophotographic apparatus.

FIG. 5 shows a conventional example, and is an overall configuration diagram showing main parts of an electrophotographic apparatus.

FIG. 6 shows a conventional example and is an explanatory diagram illustrating how a toner image is transferred from a photoreceptor to a transfer belt.

[Explanation of symbols]

6 Second photoreceptor drive roller (drive roller) 7
Cleaning roller device 8 Cleaning roller device 37 Cleaning roller 37a Roller core portion 37b Adhesive portion 40 Cleaning roller 40a Roller core portion 40b Adhesive portion

Claims (1)

[Claims] Claims: 1. A method for removing foreign matter attached to the back surface of a photoreceptor while being pressed against the back surface of a belt-shaped photoreceptor, or while being pressed against and driven by a photoreceptor driving roller that drives the photoreceptor. In a cleaning roller device equipped with a cleaning roller having an adhesive portion formed on its surface for removing foreign matter adhering to the circumferential surface of a photoreceptor drive roller, the cleaning roller has a magnetic field generating means in a roller core. A cleaning roller device for an electrophotographic device, characterized in that: