JP2006178124A - Cleaning device and image forming apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device realizing space saving by reducing component parts without lowering a cleaning effect, and an image forming apparatus equipped therewith. <P>SOLUTION: A recovery screw 8 is arranged inside a rubbing roller 6 formed to be hollow, and residual toner scraped from the surface of a photoreceptor drum 1 by a cleaning blade 9 or the rubbing roller 6 is guided into the rubbing roller 6 through a plurality of openings provided on the surface of the rubbing roller 6. By rotating the recovery screw 8 inside the rubbing roller 6 in a direction shown by an arrow A in Figure, the toner inside the rubbing roller 6 is successively conveyed in a direction shown by an arrow B, and discharged to the outside of the cleaning device from a toner discharge port provided on the base of a housing 16 and stored in a bottle for wastes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning device for removing untransferred toner remaining on the surface of a photosensitive drum, and an image forming apparatus using the same.

  In recent years, an a-Si photosensitive drum has been widely used as an image carrier of an image forming apparatus using an electrophotographic process. The a-Si photoconductor drum has high hardness and excellent durability, and its characteristics as a photoconductor are hardly deteriorated even after long-term use. In addition, the image carrier is excellent in environmental safety.

  In an image forming apparatus using such an a-Si photosensitive drum, it is known that image flow tends to occur due to its characteristics. That is, when charging is performed using the charging unit, ozone is generated by discharging of the charging unit. The components in the air are decomposed by the ozone, and ion products such as NOx and SOx are generated. Since this ion product is water-soluble, it adheres to the photosensitive drum and enters into a roughness structure of about 0.1 μm on the surface of the photosensitive drum, so that it can be removed by a cleaning system used in a general-purpose machine. In addition, the resistance of the surface of the photosensitive drum is lowered by taking in moisture in the atmosphere. As a result, the lateral flow of the potential occurs at the edge portion of the electrostatic latent image formed on the surface of the photosensitive drum, and as a result, the image flow may occur.

  Conventionally, by putting a heater in the photoconductor drum, energy is given to release the moisture taken in by the ion products, and the resistance decrease on the surface of the photoconductor drum in a high-humidity environment is suppressed. ing. However, in such an apparatus, the number of parts for configuring the heater is increased, a heater mounting space is required, and power consumption is increased, leading to an increase in size and cost of the apparatus. In addition, it takes time for the surface of the photoreceptor to be heated to a predetermined temperature, which requires a long processing time and is not preferable from the viewpoint of safety.

  In view of this, a method of reducing the image flow by suppressing a decrease in the resistance of the surface of the photosensitive drum with a simple configuration has been proposed. In Patent Documents 1 and 2, as shown in FIG. Disclosed is a method for removing ozone products without using a heater or the like by executing a refresh mode in which a photosensitive member is polished by the interaction of toner and polishing means (sliding roller and cleaning blade) at a predetermined timing. Yes.

  In FIG. 6, the image forming unit 15 includes a charging unit 2, an exposure unit 3, a developing unit 4, a transfer roller 5, a rubbing roller 6, and a cleaning blade along the rotation direction (arrow A direction) of the photosensitive drum 1. 9. A static eliminating device 10 is provided. The photosensitive drum 1 is formed, for example, by laminating a photosensitive layer made of a-Si on an aluminum drum, and the charging unit 2 charges the surface. Then, an electrostatic latent image in which charging is attenuated is formed on the surface that has received the laser beam from the exposure unit 3. The charging unit 2 charges the surface of the photosensitive drum 1 by discharging (for example, corona discharge). For example, the charging unit 2 is discharged by applying a high voltage using a thin wire or the like as an electrode. .

  The exposure unit 3 irradiates the photosensitive drum 1 with a light beam (for example, a laser beam) based on the image data to form an electrostatic latent image on the surface of the photosensitive drum 1. The developing unit 4 includes a developing sleeve 4a disposed so as to face the photosensitive drum 1, and a developer image contained therein is attached to the electrostatic latent image on the photosensitive drum 1 by the developing sleeve 4a to form a toner image. It is something to be made.

  As is well known, an electrostatic latent image is recorded by the exposure unit 3 on the photosensitive drum 1 uniformly charged by the charging unit 2 after static elimination by the static eliminator 10, and the electrostatic latent image is developed by reversal development. In step 4, the toner image is visualized and the toner image is transferred onto the sheet 11 by the transfer roller 5. Untransferred toner that has not been transferred by the transfer roller 5 is removed from the surface of the photosensitive drum 1 by the rubbing roller 6 and the cleaning blade 9 as residual toner, and the removed residual toner is illustrated by a toner recovery device such as a recovery screw 8. Not transported to waste bottle.

  A cleaning device 14 includes a rubbing roller 6, a cleaning blade 9, and a collecting screw 8, which is a polishing system for polishing the photoconductor drum 1 in a housing 16, and pressurizes the rubbing roller 6 to the surface of the photoconductor at a constant pressure. Spring 7 is provided. The rubbing roller 6 has a configuration in which the periphery is covered with foamed urethane rubber around the shaft. The rubber hardness is adjusted to 50 degrees through the shaft. As the abrasive toner, titanium oxide, strontium titanate, alumina, or the like is embedded as an abrasive on the surface of the toner particles, and the toner is electrostatically attached to the toner surface. What is being used is used.

  This technology is an image forming apparatus having a configuration in which the surface roughness of an a-Si photosensitive drum is polished so as to be Rz500 angstroms or less. By polishing to this surface roughness, ion generation as described above is performed. Even if an object adheres to the surface of the photosensitive drum, it can be sufficiently removed.

  In order to realize the above technique, the above-described rubbing roller 6, cleaning blade 9, and recovery screw 8 that guides toner scraped off from the surface of the photosensitive drum 1 to a waste bottle are required. With the demand for space saving and compactness, further downsizing of the image forming unit is required. Therefore, in the cleaning device, it has been essential to reduce the size of components or reduce the number of components as much as possible.

Japanese Patent Laid-Open No. 11-3014 JP-A-11-133462

  In view of the above problems, an object of the present invention is to provide a cleaning device capable of saving space by reducing component parts without deteriorating the cleaning effect and an image forming apparatus including the same.

  In order to achieve the above object, the present invention provides a rubbing roller that contacts the surface of the photosensitive drum with a predetermined pressure, polishes the surface of the photosensitive drum, and scrapes and removes residual toner adhering to the surface of the photosensitive drum. And a cleaning screw that discharges residual toner scraped off by the rubbing roller to the outside of the apparatus, and a housing that houses the rubbing roller and the collecting screw. It is arranged in a hollow part formed inside the roller, and an opening communicating with the hollow part is formed on the surface of the rubbing roller.

  According to the present invention, in the cleaning device configured as described above, the opening is formed such that the surface area in the rotational direction of the rubbing roller is the same in the entire width direction.

  The present invention also provides an image forming apparatus equipped with the cleaning device having the above-described configuration.

  According to the first configuration of the present invention, the recovery screw is disposed in the hollow portion formed inside the rubbing roller, and the opening that communicates with the hollow portion is formed on the surface of the rubbing roller. Therefore, the space for arranging the cleaning device is not required, and the cleaning device can be reduced in size and size. Further, since the toner scraped off from the surface of the photosensitive drum is discharged to the outside of the apparatus by the recovery screw in the rubbing roller through the opening, the toner inside the apparatus can be discharged smoothly.

  Further, according to the second configuration of the present invention, in the cleaning device having the first configuration, the opening is formed so that the surface area in the rotational direction of the rubbing roller is the same in the entire width direction. The surface of the photosensitive drum can be uniformly polished without variation in the surface area of the roller.

  In addition, according to the third configuration of the present invention, mounting the cleaning device having the first or second configuration contributes to space saving and compactness of the image forming apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus equipped with a cleaning device of the present invention. Portions common to FIG. 6 of the conventional example are denoted by the same reference numerals and description thereof is omitted. In the image forming apparatus 20, an image forming unit 15 is disposed above the transport belt 21. The image forming unit 15 forms a predetermined image through each process of charging, exposure, development, and transfer.

  The image forming unit 15 is provided with a photosensitive drum 1 that carries a visible image (toner image), and the toner image formed on the photosensitive drum 1 moves adjacent to the image forming unit. The image is transferred onto a sheet (recording medium) 11 carried and conveyed by the conveyance belt 21, further fixed on the sheet 11 at the fixing unit 22, and then discharged from the apparatus main body. An image forming process is performed on the photosensitive drum 1 while rotating the photosensitive drum 1 clockwise in FIG. Since the image forming process is the same as that of the conventional example, description thereof is omitted.

  The sheet 11 on which the toner image is transferred is accommodated in a plurality of paper feed cassettes 23a, 23b, and 23c for storing paper and a stack bypass (manual feed tray) 23d provided above the paper feed cassettes 24a, 23b, and 23d. The toner is supplied onto the conveyor belt 21 via the roller 25 and is conveyed to the position of the photosensitive drum 1. A sheet made of dielectric resin is used for the transport belt 21, and a belt in which both ends thereof are overlapped and joined to form an endless shape, or a belt without a seam (seamless) is used.

  The conveying belt 21 is stretched between a downstream driving roller 26 and an upstream driven roller 27. When the conveying belt 21 starts to rotate counterclockwise, the sheet 11 is transferred from the registration roller 25 to the conveying belt 21. It is transported up. At this time, the image writing signal is turned ON, and an image is formed on the photosensitive drum 1 at a predetermined timing. A toner image on the photosensitive drum 1 is transferred onto the sheet 11 by applying an electric field to the lower portion of the photosensitive drum 1 with the transfer roller 5 to which a predetermined transfer voltage is applied. The sheet 11 is held on the conveyor belt 21 with an electrostatic adsorption force.

  The sheet 11 on which the toner image is transferred is detached from the conveyance belt 21 and conveyed to the fixing unit 22. In addition, the photosensitive drum 1 after the toner image is transferred is prepared for the subsequent formation of a new electrostatic latent image, and the toner remaining on the surface is removed by the cleaning device 14. The sheet 11 conveyed from the conveyance belt 21 to the fixing unit 22 is heated and pressed by the fixing roller 22a, and the toner image is fixed on the surface of the sheet 11 to form a predetermined image. The sheet 11 on which the image is formed is then discharged to a discharge tray 29 by a discharge roller 28.

  FIG. 2 is a side sectional view showing the configuration of the cleaning device of the present invention. Portions common to FIG. 6 of the conventional example are denoted by the same reference numerals and description thereof is omitted. The present invention is characterized in that the rubbing roller 6 is formed in a hollow shape, and the recovery screw 8 is disposed in the rubbing roller 6. By adopting the configuration of the present invention, the arrangement space for the recovery screw 8 that has been necessary in the past is not required, so that the cleaning device 14 can be reduced in size, which contributes to downsizing and downsizing of the image forming apparatus. Can do.

  FIG. 3 is a longitudinal sectional view of the cleaning device of the present invention (cross section AA ′ in FIG. 2). The recovery screw 8 has a configuration in which a spiral blade 8b is provided around the support shaft 8a and is rotatably supported in the rubbing roller 6. The rubbing roller 6 is connected to a rubbing roller drive motor 35 via gears 33 and 34, and a recovery screw drive motor 36 is directly connected to a support shaft 8a of the recovery screw 8, and each is on the same rotational axis. It is rotationally driven separately at a predetermined speed.

  Residual toner scraped off from the surface of the photosensitive drum 1 (see FIG. 2) by the cleaning blade 9 or the rubbing roller 6 enters the rubbing roller 6 through a plurality of openings 30 provided on the surface of the rubbing roller 6. Led. Then, when the recovery screw 8 in the rubbing roller 6 rotates in the direction of arrow A in the figure, the toner in the rubbing roller 6 is sequentially conveyed in the direction of arrow B, and a toner discharge port provided on the bottom surface of the housing 16. It is discharged from 31 to the outside of the apparatus and stored in the waste bottle 32.

  Here, since the rubbing roller 6 is provided at the bottom of the housing 16, the toner scraped off from the photosensitive drum 1 falls by gravity and is efficiently guided into the rubbing roller 6. The arrangement of the rollers 6 is not limited to the bottom of the housing 16. For example, when the toner is disposed in the center of the housing 16, the toner is gradually accumulated in the housing 16 and is guided into the rubbing roller 6 from the opening 30 when the toner reaches the position of the rubbing roller 6. Therefore, the cleaning device of the present invention is not only an image forming device in which the cleaning device 14 is disposed on the side of the photosensitive drum 1 as shown in FIG. It can also be mounted on an image forming apparatus.

  4A and 4B are a plan view and a cross-sectional view showing an example of the configuration of the rubbing roller used in the cleaning device of the present invention. As shown in FIG. 4, the developing roller 6 includes a pipe-like shaft 6a having a hollow portion 37 formed therein, and a rubber layer 6b made of urethane foam rubber covering the surface of the shaft 6a. Reference numeral 37 denotes a collection screw 8 that conveys toner inside the apparatus to the outside.

  On the surface of the rubbing roller 6, a large number of openings 30 are formed so as to penetrate the rubber layer 6 b and the shaft 6 a and communicate with the hollow portion 37. The cleaning blade 9 (see FIG. 2) or the rubbing roller 6 The toner removed from the surface of the photosensitive drum 1 (see FIG. 2) is guided to the hollow portion 37 through the opening 30.

  When the opening 30 is provided, the surface area of the rubbing roller 6 is reduced by that amount, so that the polishing effect of the photosensitive drum 1 may change between the portion where the opening 30 is provided and the portion where the opening 30 does not exist. There is. Therefore, in the present invention, openings 30 having the same area are arranged in a lattice pattern as shown in FIG.

  The arrangement pattern of the openings 30 is not limited to the lattice shape as shown in FIG. 4A. For example, as shown in FIG. 5, a pattern in which a large number of slits are arranged obliquely may be used. That is, by setting the shape and the arrangement pattern of the openings 30 so that the surface area of the rubbing roller 6 in the rotational direction (the direction of arrow A in FIG. 4B) is equal in the entire width direction of the rubbing roller 6. Generation of uneven polishing of the photosensitive drum 1 can be prevented.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the rubbing roller 6 and the collecting screw 8 are rotated using separate motors 35 and 36, but both the rubbing roller 6 and the collecting screw 8 are rotated using one motor. It can also be configured. In that case, the rubbing roller 6 and the collecting screw 8 may be rotated at the same speed, but it is preferable to rotate each at an optimal rotational speed using a speed reduction mechanism such as a gear train.

  In the above embodiment, only the configuration including the rubbing roller 6 and the cleaning blade 9 is described as the polishing system of the cleaning device. However, the configuration of the present invention includes, for example, the configuration including only the rubbing roller 6. Alternatively, the present invention can be applied to cleaning devices having various configurations including the rubbing roller 6 and the collection screw 8 such as a configuration including a fur brush instead of the cleaning blade 9.

  The present invention includes a rubbing roller that contacts the surface of the photosensitive drum with a predetermined pressure, polishes the surface of the photosensitive drum, and scrapes off and removes residual toner attached to the surface of the photosensitive drum. In a cleaning device comprising a recovery screw for discharging the dropped residual toner to the outside of the apparatus, and a housing for storing the rubbing roller and the collecting screw, the collecting screw is disposed in a hollow portion formed inside the rubbing roller. In addition, an opening communicating with the hollow portion is formed on the surface of the rubbing roller.

  This eliminates the need for a space for disposing the recovery screw, and the toner scraped off from the surface of the photosensitive drum is discharged to the outside of the apparatus by the recovery screw in the rubbing roller through the opening. The size and size of the cleaning device can be reduced without reducing it.

  Further, since the openings are formed so that the surface area in the rotational direction of the rubbing roller is the same in the entire width direction, the surface area in the width direction of the rubbing roller can be made uniform to prevent uneven polishing of the surface of the photosensitive drum. it can.

  In addition, by mounting the cleaning device of the present invention, it is possible to realize space saving and compactness of the image forming apparatus easily and at low cost without deteriorating the cleaning effect.

FIG. 1 is a schematic cross-sectional view showing an overall configuration of an image forming apparatus of the present invention. These are side surface sectional views which show the structure of the cleaning apparatus of this invention. These are the longitudinal cross-sectional views which show the structure of the cleaning apparatus of this invention. These are the top view and sectional drawing which show one structural example of the rubbing roller used for the cleaning apparatus of this invention. These are top views which show the other example of the arrangement pattern of an opening part. These are the schematic diagrams which show the structure of the image forming part of the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 3 Exposure unit 4 Developing unit 4a Developing sleeve 5 Transfer roller 6 Sliding roller 6a Shaft 6b Rubber layer 7 Spring 8 Collection screw 8a Support shaft 8b Spiral blade 9 Cleaning blade 14 Cleaning device 15 Image forming part 16 Housing 20 Image Forming device 30 Opening portion 31 Toner discharge port 32 Waste bottle 35 Rub roller driving motor 36 Recovery screw drive motor 37 Hollow portion

Claims (3)

A rubbing roller that contacts the surface of the photoconductive drum with a predetermined pressure, polishes the surface of the photoconductive drum and scrapes off and removes residual toner adhering to the surface of the photoconductive drum, and a residue scraped off by the rubbing roller In a cleaning device comprising a recovery screw for discharging toner to the outside of the device, and a housing for storing the rubbing roller and the recovery screw,
A cleaning device, wherein the recovery screw is disposed in a hollow portion formed inside the rubbing roller, and an opening communicating with the hollow portion is formed on a surface of the rubbing roller.   The cleaning device according to claim 1, wherein the opening is formed so that a surface area in a rotation direction of the rubbing roller is the same in the entire width direction.   An image forming apparatus on which the cleaning device according to claim 1 is mounted.

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