JP2005316086A - Cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device capable of efficiently removing sticking matter on the surface of a photoreceptor drum with a simple structure. <P>SOLUTION: A scraper 12 is fixed to a bracket 11, and both ends of the bracket 11 are fixed to both bearings 11a and 22b provided for a slide roller 10. In addition, a line Lb connecting the center of a support shaft 21 and the center of the shaft 22 of the slide roller 10 is parallel to a straight line perpendicular to the direction of the contact pressure of the slide roller 10 on the photoreceptor drum 1, that is, a pressure acting line La. The point of contact between the scraper 12 and the slide roller 10 is located on a straight line parallel to the pressure acting line La. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning device, and more particularly to a cleaning device that rubs and removes deposits on an a-Si (amorphous silicon) photosensitive drum.

  In an electrophotographic image forming apparatus, a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and the like are provided around the photosensitive drum. Then, after the photosensitive drum is charged by the charging unit, exposure is performed by the exposure unit, an electrostatic latent image is formed on the surface of the photosensitive drum, and developed by the developing unit. Thereafter, the developed toner image is transferred onto the transfer material by the transfer means, and further fixed by the fixing means, and the image-formed transfer material is discharged to the discharge portion. Residual developer remaining on the photosensitive drum is cleaned by a cleaning unit.

  In such an image forming process, ion products such as NOx and SOx are generated in the discharging process by the charging means, and these adhere to the surface of the photosensitive drum. Also, recording paper additives and paper dust adhere to the surface of the photosensitive drum. These ion products, paper dust, and the like may adsorb moisture in the image forming apparatus and reduce the surface resistance of the photosensitive drum. For this reason, electric charges are liable to leak, and image disturbance occurs. Since the surface of the organic photoreceptor is relatively soft, when the cleaning means rubs the surface, the surface is scraped and ion products and paper dust attached to the surface are removed.

  However, since the surface hardness of the a-Si photoconductor is higher than that of the organic photoconductor and the surface is hardly scraped off, ion products and paper dust adhered to fine dents on the surface are removed by a cleaning means. It ’s hard. Therefore, phenomena such as charge leakage due to the above-described ion products are particularly likely to occur in the a-Si type photoreceptor.

In order to prevent image disturbance due to such charge leakage, a cleaning roller made of an elastic material such as foamed synthetic rubber is disposed in the cleaning device, and the cleaning roller is always pressed against the surface of the photosensitive drum to thereby provide a photosensitive member. A method has been proposed in which the drum surface is polished, a scraper is brought into contact with the cleaning roller, and toner on the cleaning roller is removed. On the other hand, if the pressure contact force between the scraper and the cleaning roller is too large, the pressure contact force between the cleaning roller and the photosensitive drum increases, and image deterioration due to image jitter or the like occurs. In view of this, there has been proposed an improved drive mechanism for making the pressure contact between the cleaning roller and the surface of the photosensitive drum constant.
Japanese Patent Publication No. 6-8976 JP 2003-173117 A

  The invention described in Japanese Patent Publication No. 6-8976 describes a method of increasing the scraping effect on the cleaning roller by bringing the scraper into contact with the polishing marks of the cleaning roller in the forward direction. However, the method for attaching the scraper and the method for driving the cleaning roller are not described. Therefore, depending on the pressure contact force between the scraper and the cleaning roller, the pressure contact force from the cleaning roller to the surface of the photosensitive drum may be too large, and image jitter may occur. Further, when the pressure contact force between the scraper and the cleaning roller is small, a scraping failure may occur.

  Japanese Patent Laid-Open No. 2003-173117 proposes a mechanism for driving a cleaning roller that makes the pressure contact force from the cleaning roller to the surface of the photosensitive drum constant. However, there is no description about the scraper, and the contact of the cleaning roller to the surface of the photosensitive drum may become unstable depending on the contact method of the scraper.

  An object of the present invention is to provide a cleaning device that has a simple structure and can efficiently remove deposits on the surface of the photosensitive drum, thereby extending the life of the photosensitive drum and forming a high-quality image. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

  A cleaning device according to a first aspect of the present invention is a device that rubs and removes deposits on the photosensitive drum, and slidably presses the photosensitive drum so as to swing, and swings coaxially with the sliding roller. However, a scraper that contacts the rubbing roller is provided.

  In this apparatus, the scraper and the rubbing roller swing coaxially. Therefore, when the rubbing roller is pressed against the surface of the photoconductor drum to clean the surface of the photoconductor drum, the scraper and the rubbing roller are compared with the case where the scraper and the rubbing roller swing independently. The pressure contact force is constant. For this reason, the pressure contact force between the rubbing roller and the surface of the photosensitive drum hardly fluctuates, and the deposits on the photosensitive drum can be reliably removed, and the occurrence of image jitter can be suppressed.

  According to a second aspect of the present invention, the cleaning device according to the first aspect further includes a bearing that rotatably supports the rubbing roller, and a bracket fixed to the bearing of the rubbing roller, and the scraper is provided on the bracket. Yes.

  In this apparatus, a scraper is provided on a bracket, and the bracket is fixed to a bearing of a rubbing roller. Therefore, the bracket swings coaxially with the rubbing roller, and the scraper provided on the bracket also swings coaxially with the rubbing roller.

  In this apparatus, the scraper and the rubbing roller are swingable coaxially with a simple structure.

  According to a third aspect of the present invention, there is provided a cleaning apparatus according to the first or second aspect, comprising: a first gear fixed to the photosensitive drum; and a second gear fixed to the rubbing roller and meshed with the first gear; The contact point between the rubbing roller and the rubbing roller is provided on a straight line parallel to the line of action of the front meshing pressure angle between the first gear and the second gear. Here, the line of action of the front meshing pressure angle of the first gear and the second gear refers to a straight line inclined by the pressure angle from the common tangent of the pitch circle of the first gear and the second gear.

  In this apparatus, the contact point between the scraper and the rubbing roller is provided on a straight line parallel to the line of action of the front meshing pressure angle between the first gear and the second gear. Therefore, the frictional force generated by the friction between the scraper and the rubbing roller does not affect the pressing force between the rubbing roller and the photosensitive drum, and the rubbing roller is pressed against the photosensitive drum with a more stable pressing force. Is possible.

  According to a fourth aspect of the present invention, in the cleaning device according to any one of the first to third aspects, the photosensitive drum is an a-Si type photosensitive member.

  In general, since the surface of an organic photoreceptor is relatively soft, when the surface is rubbed with a cleaning blade or the like, the surface is scraped and ion products and paper dust attached to the surface are removed. -Since the Si photoconductor has a high surface hardness, it is difficult to remove ion products, paper dust, and the like adhering to fine dents on the surface with a normal cleaning blade. Therefore, a rubbing roller as in the present invention is required.

  In the cleaning device of the present invention, since the scraper swings coaxially with the rubbing roller, the pressure contact force between the scraper and the rubbing roller is constant. Therefore, it is possible to reliably remove the deposits on the photosensitive drum with a stable pressure contact force and to extend the life of the photosensitive drum. Further, it is possible to suppress the occurrence of image jitter caused by an excessive pressure contact force of the rubbing roller with respect to the photosensitive drum.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus in which an embodiment of the present invention is adopted. A photoconductor drum 1 using an a-Si photoconductor is disposed in the approximate center of the image forming apparatus 100. Around the photoconductor drum 1, a charging device 2, an exposure device 3, a developing device 4, and a transfer device are arranged. A device 5, a separation device 6 and a cleaning device 7 are arranged. A fixing device 8 is disposed on the downstream side of the photosensitive drum 1 in the sheet conveyance direction. The photosensitive drum 1 has an electrostatic latent image formed on the surface. The charging device 2 is installed above the photosensitive drum 1 and is a device for uniformly charging the photosensitive drum 1. The exposure device 3 is a device for forming an electrostatic latent image on the photosensitive drum 1 based on a document image read from a document reading device (not shown). The developing device 4 is a device that forms a toner image by supplying toner to the surface of the photosensitive drum 1 on which the electrostatic latent image is formed. The transfer device 5 is a device for transferring the toner image on the photosensitive drum 1 to a sheet. The separation device 6 is a device for separating the paper on which the toner image has been transferred from the photosensitive drum 1. The cleaning device 7 is a device for cleaning deposits such as residual developer remaining on the photosensitive drum 1 and ion products adhered on the photosensitive drum. The fixing device 8 is a device for fixing the transferred toner image on a sheet.

  Next, the cleaning device 7 provided in the image forming apparatus 100 will be described. As shown in FIG. 3, the cleaning device 7 mainly includes a rubbing roller 10 in contact with the photoconductive drum 1 and a toner collecting screw provided on the side facing the photoconductive drum 1 across the rubbing roller 10. 13 and a cleaning blade 14 provided on the rubbing roller 10 and in sliding contact with the photosensitive drum 1. A bracket 11 and a scraper 12 are disposed around the rubbing roller 10 as shown in FIG. The bracket 11 is fixed to the bearing of the rubbing roller 10. The scraper 12 is provided on the bracket 11 and is in contact with the surface of the rubbing roller 10 opposite to the photosensitive drum 1 with the rubbing roller 10 interposed therebetween. Further, as shown in FIGS. 2 and 3, the cleaning device 7 is disposed in the frame 30 together with the photosensitive drum 1, the charging device 2, and the like, and is drawn out and inserted (attached) to the image forming apparatus main body 100. ) Is possible.

  Next, the swing mechanism of the rubbing roller 10 will be described. As shown in FIG. 4, the rubbing roller 10 and the shaft 22 are integrally provided, and are rotatably supported by the arm member 20 via a bearing 22 a shown in FIG. 5. The arm member 20 has an inverted L-shaped first portion 20a and a second portion 20b with the support shaft 21 as a center. The tip of the first portion 20 a supports the bearing 22 a of the rubbing roller 10, and the tip of the second portion 20 b is connected to the frame body 30 of the cleaning device 7 via the coil spring 23. The arm member 20 can swing around a support shaft 21 provided at the center thereof. When the photosensitive drum 1 is cleaned by the rubbing roller 10, the arm member 20 is biased counterclockwise by the coil spring 23. The rubbing roller 10 is pressed against the surface of the photosensitive drum 1 by this biasing force.

  Here, as shown in FIG. 6, the position of the support shaft 21 of the arm member 20 is such that a line Lb connecting the center of the support shaft 21 and the center of the shaft 22 of the rubbing roller 10 is fixed to the photosensitive drum 1. The first gear 1a and the second gear 10a fixed to the rubbing roller 10 are parallel to the action line La of the front meshing pressure angle. With this configuration, when the driving force is transmitted between the first gear 1a and the second gear 10a, the swing of the arm member 20 can be suppressed, and the photosensitive drum of the rubbing roller 10 can be suppressed. It is possible to suppress the occurrence of image jitter by stabilizing the pressure contact force on one surface.

  Here, the arm member and its support shaft 21 are provided on the downstream side of rotation of the rubbing roller 10. However, the same effect can be obtained by providing the arm member and its support shaft 21 on the upstream side of rotation of the rubbing roller 10. can get.

  Next, the bracket 11 will be described. As shown in FIGS. 3 to 5, the bracket 11 is provided below the rubbing roller 10, and extends in the axial direction of the rubbing roller 10. It is comprised by the parts 112 and 113 connected with the bearings 22a and 22b provided in both ends. Specifically, 112 fixed to the bearing 22a of the rubbing roller 10 has a diameter slightly larger than the diameter of the bearing 22a, and a hole in which the shaft of the rubbing roller 10 is disposed in the center. It is a C-shaped disk having an opening in part. The bottom of the disk has a portion 112 a extending downward, and this extended portion 112 a is fixed to the plate-like plate portion 111. The plate-like plate portion 111 has a width that is slightly smaller than the diameter of the rubbing roller 10, and both ends in the longitudinal direction are fixed to C-shaped discs 112 and 113, respectively. The plate-shaped plate portion 111 is composed of a bottom portion 111a and side portions 111b and 111c extending perpendicularly to the bottom portion 111a. Thus, since both ends of the bracket 11 are fixed to the bearings 22a and 22b of the rubbing roller 10, when the rubbing roller 10 is brought into pressure contact with the photosensitive drum 1, the bracket 11 is also in contact with the rubbing roller 10. It can swing together.

  The scraper 12 is a plate-like member formed extending in the axial direction of the rubbing roller 10, and its bottom is fixed to the side wall 111 c of the bracket 11. Here, since the scraper 12 is fixed to the bracket 11 and the bracket 11 is fixed to the bearing of the rubbing roller 10, the scraper 12 is integrated with the rubbing roller 10 and swings around the support shaft 21. It is possible to move. Therefore, when the rubbing roller 10 moves in a direction away from the photosensitive drum 1 by the pressing force from the photosensitive drum 1, the scraper 12 also presses the rubbing roller 10 while moving integrally with the rubbing roller 10. The rubbing roller 10 can be reliably brought into pressure contact with the photosensitive drum 1.

  Here, as shown in FIG. 6, the contact 12 a with which the scraper 12 presses against the rubbing roller 10 is a first gear 1 a fixed to the photosensitive drum 1 and a second gear fixed to the rubbing roller 10. 10a is provided on a straight line Lc parallel to the action line La of the front meshing pressure angle with 10a.

  Next, an image forming operation will be described. During image formation, the photosensitive drum 1 is charged by the charging unit 2 and then exposed by the exposure unit 3 to form an electrostatic latent image on the surface of the photosensitive drum 1 and developed by the developing unit 4. Is done. Thereafter, the developed toner image is transferred onto the transfer material by the transfer unit 5, and the transfer material is separated from the photosensitive drum by the separation unit 6. Further, the transfer material fixed with heat and pressure by the fixing means 8 and image-formed is discharged to a discharge portion. The residual developer remaining on the photosensitive drum 1 is cleaned by the cleaning blade 14 and the rubbing roller 10 in the cleaning device 7 and discarded in a waste toner container (not shown).

  In such an image forming process, ozone is generated by the discharge of the charging device 3, and ion products such as NOx and SOx are generated by the oxidizing action of the ozone and adhere to the surface of the photosensitive drum 1. Also, transfer material additives and paper dust adhere to the surface of the photosensitive drum 1. The first gear 1a fixed to the photosensitive drum 1 is driven through another intermediate gear (not shown) provided in the image forming apparatus, and the photosensitive drum 1 is rotated in the clockwise direction. The rubbing roller 10 is rotated counterclockwise by the engagement of the second gear 10a and the first gear 1a. At that time, the rubbing roller 10 is pressed against the surface of the photosensitive drum 1 by the urging force of the coil spring 23 connected to the arm member 20, polishes the surface of the photosensitive drum 1, and adheres to the photosensitive drum 1. Cleaning the ion products, paper dust, and transfer material additives. Further, the scraper 12 is brought into pressure contact with the rubbing roller 10 to remove the deposits remaining on the rubbing roller 10.

  In this embodiment, the scraper 12 is fixed to the bracket 11, and both end portions of the bracket 11 are fixed to both bearings 22 a and 22 b of the rubbing roller 10. Therefore, when the rubbing roller 10 is pressed against the photosensitive drum 1, the scraper 12 can swing together with the rubbing roller 10 together with the bracket 11. Further, the contact point 12 a with which the scraper 12 presses the rubbing roller 10 has a front meshing pressure angle between the first gear 1 a fixed to the photosensitive drum 1 and the second gear 10 a fixed to the rubbing roller 10. It is provided on a straight line Lc parallel to the action line La. Here, when the rubbing roller 10 presses the photosensitive drum 1 to clean the photosensitive drum 1, the rubbing roller 10 is at the contact point 1 a between the rubbing roller 10 and the photosensitive drum 1. Receives a horizontal force trying to move away from 1. On the other hand, at the contact 12 a where the scraper 12 presses against the rubbing roller 10, the rubbing roller 10 receives a horizontal force directed toward the photosensitive drum 1. Since the opposite horizontal forces cancel each other, the rubbing roller 10 can be brought into pressure contact with the photosensitive drum 1 with a stable pressure contact force.

  As described above, in this embodiment, since the scraper 12 swings coaxially with the rubbing roller 10, the scraper is pressed when the rubbing roller 10 is pressed against the photoconductor drum 1 to clean the surface of the photoconductor drum 1. The pressure contact force between 12 and the rubbing roller 10 is constant. Further, the contact point 12 a with which the scraper 12 presses the rubbing roller 10 has a front meshing pressure angle between the first gear 1 a fixed to the photosensitive drum 1 and the second gear 10 a fixed to the rubbing roller 10. It is provided on a straight line Lc parallel to the action line La. Therefore, the deposits on the photosensitive drum 1 can be reliably removed with a stable pressure contact force, the occurrence of image jitter can be suppressed, and the life of the photosensitive drum 1 can be extended.

1 is a main configuration diagram of an image forming apparatus. FIG. 3 is an external view of a unit formed by a cleaning device and a photosensitive drum. Sectional drawing of the unit shown in FIG. The figure which shows the rocking | fluctuation mechanism of a rubbing roller. The perspective view which shows arrangement | positioning of a scraper and a bracket. Sectional drawing which shows the arrangement | positioning angle of a scraper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 1a First gear 2 Charging device 7 Cleaning device 10 Rub roller 10a Second gear 11 Bracket 12 Scraper 20 Arm member 21 Arm member support shaft 22 Rub roller shaft 22a Rub roller bearing 23 Compression coil La Line of action of the front meshing pressure angle of the first gear and the second gear Lb Line connecting the fulcrum of the arm member and the center of the rubbing roller Lc Tangent at the pressure contact between the scraper and the rubbing roller

Claims (4)

In a cleaning device that removes rubbing on the photosensitive drum,
A rubbing roller that is slidably pressed against the photosensitive drum;
A scraper abutting on the rubbing roller while swinging coaxially with the rubbing roller;
A cleaning device. A bearing that rotatably supports the rubbing roller;
A bracket fixed to the bearing,
The cleaning device according to claim 1, wherein the scraper is provided on the bracket. A first gear fixed to the photosensitive drum;
A second gear fixed to the rubbing roller and meshing with the first gear;
The contact point between the scraper and the rubbing roller is provided on a straight line parallel to the line of action of the front meshing pressure angle between the first gear and the second gear.
The cleaning device according to claim 1 or 2.   The cleaning device according to claim 1, wherein the photoconductor drum is an amorphous silicon photoconductor.

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