JP4972927B2 - Cleaning device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device used for an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these.

In an image forming apparatus such as a copying machine or a printer to which an electrophotographic system is applied, for example, an electrostatic latent image formed on a photosensitive drum is developed by a developing device (developing device) using a developer, and is then exposed to light. A toner image is formed on the photosensitive drum, and the toner image formed on the photosensitive drum is transferred and fixed on a recording medium to form an image.
In such an image forming apparatus, after a toner image is transferred to a recording medium or an intermediate transfer member, untransferred toner remains on the surface of the photosensitive drum. Therefore, a cleaning blade having a cleaning blade is generally provided at the subsequent stage of the transfer position. A device is provided. In this cleaning device, residual toner (waste toner) is scraped off by bringing the cleaning blade into contact with the surface of the photosensitive drum. In order to facilitate toner removal by the cleaning device, a static eliminator may be provided in front of the cleaning device.

Here, various structures have been proposed for satisfactorily cleaning the surface of the photosensitive drum with a cleaning blade (see, for example, Patent Document 1). Patent Document 1 discloses a structure that focuses on preventing the occurrence of minute vibrations and abnormal noise due to contact between the cleaning blade and the photosensitive drum. That is, Patent Document 1 discloses a configuration in which a cleaning blade is brought into contact with the surface of a photoconductor with its tip facing downward, and residual toner scraped off from the surface of the photoconductor drum by the cleaning blade is stored in a housing. ing. A lower seal that receives the residual toner and guides it to the housing; and a toner blocking member that is disposed closer to the housing than the cleaning blade and the lower seal and temporarily blocks the residual toner at the tip of the cleaning blade And the structure provided with these is disclosed.
According to such a configuration, the blocked residual toner acts as a lubricant in which the tip of the cleaning blade smoothly slides on the surface of the photosensitive drum. For this reason, it is possible to reduce minute vibrations that occur when the tip of the cleaning blade is caught on the surface of the photosensitive drum, and it is possible to prevent abnormal noise and damage to the tip of the cleaning blade. In this manner, the surface of the photoreceptor can be satisfactorily cleaned by the structure disclosed in Patent Document 1.

  On the other hand, paper dust that could not be removed by the cleaning blade during the repeated image forming process may be caught by the tip of the cleaning blade, and the edge of the cleaning blade may be deformed. Further, if paper dust gets caught at the tip of the cleaning blade, the cleaning blade is accelerated, and the surfaces of the cleaning blade and the photosensitive drum are damaged. As a result, there is a concern that the copy image may become dirty due to the residual toner passing through the cleaning blade, or black stripes on the copy image may be generated due to scratches on the surface of the photosensitive drum.

  As a structure for solving such a problem, for example, in Patent Document 2, in an image forming apparatus in which an image carrier such as a photosensitive drum or an intermediate transfer belt is cleaned with a cleaning blade, an image carrier at the end of image formation is used. A technique is disclosed in which the image carrier is rotated in the reverse direction after the rotation of the body is completed. By such reverse rotation of the image carrier after completion of image formation rotation, it is possible to eliminate the stagnation of toner or paper dust at the tip of the cleaning blade that causes residual toner or paper dust to adhere to the cleaning blade. it can. Therefore, the rotation of the image carrier is not stopped while the toner, paper dust, and the like are attached and accumulated at the tip of the cleaning blade, and the cleaning performance of the cleaning blade is maintained in the substantially initial state.

JP 11-161125 A Japanese Patent Laid-Open No. 10-10939

  However, applying the technique of maintaining the cleaning blade performance by reverse rotation disclosed in Patent Document 2 to the configuration in which the residual toner is stored using the housing disclosed in Patent Document 1 may cause inconvenient results. Is also possible. That is, there is a concern that residual toner stored in the housing slips through the lower seal during the reverse rotation of the image carrier and is ejected. As described above, the configuration disclosed in Patent Document 1 assumes that the image carrier rotates only in one direction, and does not assume that the image carrier rotates backward at a predetermined timing. Therefore, according to the prior art, it is not possible to achieve good cleaning of the surface of the photoreceptor according to Patent Document 1 and to maintain the cleaning performance of the cleaning blade according to Patent Document 2.

  The present invention has been made to solve the technical problems as described above, and the object of the present invention is in the case of a structure in which the image carrier is reversely rotated in order to maintain the cleaning performance of the cleaning blade. An object of the present invention is to provide a cleaning device, a process cartridge, and an image forming apparatus capable of satisfactorily cleaning the surface of an image carrier.

For this purpose, the cleaning device to which the present invention is applied is a cleaning device that cleans the surface of an image carrier that carries a toner image. The cleaning device has an opposing surface that faces the surface of the image carrier and an opposite surface that is located on the opposite side of the opposing surface, and has a tip that contacts the surface of the image carrier. A cleaning blade that removes the adhering waste toner by the tip, and a waste toner that has a surface that extends upward from the opposite surface of the cleaning blade and is located on the surface side of the image carrier, and has been removed by the tip of the cleaning blade Waste toner that forms a storage portion for storing the toner on the surface side of the image carrier together with the surface of the image carrier and the opposite surface of the cleaning blade , and is stored in the storage portion and acts on the opposite surface of the cleaning blade of its own weight is arranged to be positioned and a sheet member which also acts on the surface located on the surface side of the image carrier, above the tip of the cleaning blade, the reservoir It is intended to include, a discharge portion for discharging a part of the waste toner stored in.

A seal member positioned above the storage unit may be further included, and the discharge unit may discharge the waste toner from the storage unit so that the waste toner stored in the storage unit does not contact the seal member. Further, the discharge portion may be configured by an opening formed in the sheet member.
The image forming apparatus may further include a housing portion to which the cleaning blade and the sheet member are attached, and waste toner discharged through the discharge portion falls into the housing portion. In addition, the image carrier can be rotated in one direction to perform an image forming operation, and can be rotated in a direction opposite to the one direction when the image forming operation is not performed.

From another point of view, the present invention can be applied to a process cartridge that is detachably attached to an image forming apparatus main body. In other words, the process cartridge has a housing part and a tip part attached to the housing part and removing the waste toner adhering to the surface in contact with the surface of the image carrier that carries the toner image in the main body of the image forming apparatus. A cleaning blade and a surface extending on the surface side of the image carrier and extending upward from the opposite surface of the cleaning blade located on the opposite side of the surface facing the surface of the image carrier, the tip The waste toner removed by the part is dammed to the area formed by the surface located on the surface side of the image carrier, the surface of the image carrier and the opposite surface of the cleaning blade, and the opposite surface of the cleaning blade damped to the area. self-weight of the waste toner acting also acts on the surface located on the surface side of the image bearing member blocked and the member, a cleaning blade An opening formed in a portion other than the portion of the cleaning blade in contact with the distal end portion, is intended to include.

  A seal member attached to the housing portion so as to face the cleaning blade is further included, and a part of the waste toner is discharged from the opening so that the waste toner blocked by the blocking member does not contact the seal member. It can be.

Further, from another point of view of the present invention, an image forming apparatus to which the present invention is applied rotates in one direction to perform an image forming operation and has a direction opposite to the one direction when the image forming operation is not performed. An image forming apparatus provided with a rotatable image carrier. The image forming apparatus has a facing surface facing the surface of the image carrier and an opposite surface located on a side opposite to the facing surface, and has a tip portion that contacts the surface of the image carrier. A cleaning blade that removes the waste toner adhering to the tip by a tip, and a cleaning blade that extends upward from the opposite surface of the cleaning blade and is positioned on the surface side of the image carrier. A storage portion for storing waste toner removed from the surface forms a surface located on the surface side of the image carrier together with the surface of the image carrier and the opposite surface of the cleaning blade , and is stored in the storage portion and stored in the storage blade. a sheet member own weight of the waste toner acting on the opposite surface also acts on the surface located on the surface side of the image bearing member, located above the tip of the cleaning blade It is intended to include, a discharge portion for discharging a part of the waste toner stored in the reservoir.

  According to the present invention, it is possible to achieve both good cleaning of the surface of the photoreceptor and maintenance of the cleaning performance of the cleaning blade.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram showing the overall configuration of an image forming apparatus to which this embodiment is applied, and shows a digital color printer using a rotary (rotary) developing device. The image forming apparatus shown in FIG. 1 includes a photosensitive drum (image carrier) 11 that forms an electrostatic latent image on a main body 1 and carries a toner image, and a charger that charges the photosensitive drum 11 by charging it. 12. Further, the image forming apparatus exposes the charged photosensitive drum 11 to the main body 1 using, for example, a ROS (Raster Output Scanner) based on an image signal from an image processing apparatus (IPS: Image Processing System) (not shown). And an exposure device 13 for developing the electrostatic latent image formed on the photosensitive drum 11 by the exposure device 13 to form a toner image.

  The developing device 14 is a rotary developing device, and forms toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K). The four developing devices 50 are provided, and a developing roll (developer carrying member) 51 for developing the photosensitive drum 11 is provided on the periphery of the developing device 14. The developing device 14 rotates by 90 degrees about the developing device center 14 a so that the developing roll 51 provided in the desired developing device 50 faces the photosensitive drum 11. More specifically, for one print output, the Y, M, C, and K developing devices 50 are opposed to the photosensitive drum 11 in this order to enable full color output. Further, each developing device 50 is pressed on the normal line by a coil spring 55 disposed at the developing device center 14a, and the tracking roll 52 (see FIG. 2) for positioning can reliably contact the photosensitive drum 11. It is configured as follows. The photosensitive drum 11 rotates in the direction of the arrow (clockwise) in the figure, and the developing device 14 counterclockwise so that the movement in the tangential direction is the same as the rotation of the photosensitive drum 11 (clockwise). Rotate in the direction.

  Further, on the downstream side of the developing device 14 on the photosensitive drum 11, an intermediate transfer belt (intermediate transfer member) 15 that temporarily holds a toner image developed by the developing device 50 and formed on the photosensitive drum 11; A secondary transfer roll 16 for transferring the toner image formed on the intermediate transfer belt 15 to the paper, and a fixing device 17 for fixing the toner image formed on the paper by heating and pressing; Yes. Further, around the photosensitive drum 11, a cleaning blade 18 that scrapes residual toner remaining on the photosensitive drum 11 after the primary transfer to the intermediate transfer belt 15 with a front end portion 18 a (see FIG. 2), and this cleaning. A toner collecting unit 19 for collecting the toner scraped from the tip 18a (see FIG. 2) of the blade 18; The intermediate transfer belt 15 rotates four times when forming one print image. The secondary transfer roll 16 is separated from the intermediate transfer belt 15 during the first three rotations, that is, when holding the Y, M, and C toner images, and the last K toner image is superimposed. In this case, it is configured to contact the intermediate transfer belt 15.

  The intermediate transfer belt 15 contacts or abuts in a wrap shape so as to be wound around the photosensitive drum 11 by a predetermined range, thereby enabling so-called wrap transfer. For example, chloroprene having excellent oil resistance and weather resistance, EPDM having excellent weather resistance, and the like are used for the intermediate transfer belt 15 having a thickness of about 0.5 mm and a circumferential length of 443 mm. In the present embodiment, the intermediate transfer belt 15 and the photosensitive drum 11 are driven by the same drive source (not shown). In this way, by using the drive source also, it is possible to realize cost reduction and downsizing of the apparatus.

  Inside the intermediate transfer belt 15, a wrap-in roll 21 that specifies the wrap position of the intermediate transfer belt 15 on the upstream side of the rotation of the photosensitive drum 11 and a toner image formed on the photosensitive drum 11 are intermediate. A primary transfer roll 22 to be transferred onto the transfer belt 15 and a wrap-out roll 23 for specifying the wrap position of the intermediate transfer belt 15 on the downstream side of the wrap position are provided. A predetermined electric field is applied to the primary transfer roll 22 to assist primary transfer. The wrap-in roll 21 and the wrap-out roll 23 are placed in a GND or floating state.

  A backup roll 24 that assists secondary transfer by the secondary transfer roll 16 is provided inside the intermediate transfer belt 15. In the secondary transfer portion where the secondary transfer is performed by the secondary transfer roll 16 and the backup roll 24, a predetermined potential difference is required between the backup roll 24 and the secondary transfer roll 16. When the secondary transfer roll 16 is connected to a high voltage, the other backup roll 24 that faces the secondary transfer roll 16 is connected to GND.

An intermediate transfer body cleaner 30 that removes toner on the intermediate transfer belt 15 after the secondary transfer is provided downstream of the secondary transfer portion on the intermediate transfer belt 15. The intermediate transfer body cleaner 30 includes a scraper 25 for scraping off toner remaining after the secondary transfer, a brush roll 26 for further scraping off toner remaining after cleaning by the scraper 25, and the scraper 25 and the brush roll. 26, a second toner recovery bottle 29 that recovers the toner scraped off by the camera 26. Inside the intermediate transfer belt 15, a cleaning backup roll 27 that assists the cleaning work by the scraper 25 and a cleaning backup roll 28 that assists the cleaning work by the brush roll 26 are provided.
Note that the scraper 25 and the brush roll 26 are separated from the intermediate transfer belt 15 at the beginning of image formation so as not to scrape off the toner image being superimposed, and they are integrated at a predetermined timing. It is configured to contact the intermediate transfer belt 15.

  The image forming apparatus to which the exemplary embodiment is applied includes a control unit 40 that controls the movement of each member of the image forming apparatus, and the toner formed on the intermediate transfer belt 15 that is provided adjacent to the intermediate transfer belt 15. And a reflective photosensor 41 for detecting a patch. The photo sensor 41 can detect the position of the intermediate transfer belt 15 in the rotational direction by reading a patch formed in the longitudinal direction of the intermediate transfer belt 15.

  Here, in the configuration described above, a part of the cartridge may be formed. There are several possible forms of the process cartridge (CRU (Customer Replaceable Unit)) formed into a cartridge. One example of the process cartridge (CRU (Customer Replaceable Unit)) will be described. it can. In addition, the photosensitive drum 11, the charger 12, the cleaning blade 18, and the toner recovery unit 19 may be integrated into a cartridge.

  Next, an image forming process using the image forming apparatus shown in FIG. 1 will be described. The image forming apparatus receives an output request from an externally connected PC (Personal Computer), an image reading apparatus, or the like, and starts an image forming process based on an instruction from the control unit 40. In the case of full-color print output, the developing device 14 first rotates so that the yellow developing device 50 faces the photosensitive drum 11. First, when a yellow toner image is formed, the photosensitive drum 11 that rotates in the clockwise direction is charged by the charger 12 and then turned yellow at the exposure unit by, for example, laser light from the exposure device 13. Exposure based on corresponding image information is performed, and an electrostatic latent image is formed. Thereafter, after development is performed by the developing roller 51, a yellow toner image is transferred to the intermediate transfer belt 15 in a lap-shaped contact range or lap range. At this time, the secondary transfer roll 16, the scraper 25, and the brush roll 26 are retracted (separated) from the intermediate transfer belt 15, and the toner image on the intermediate transfer belt 15 is not scraped off by these.

  After the primary transfer, the surface of the photosensitive drum 11 is scraped off by the cleaning blade 18 and moves to the charger 12 for the next toner image formation. Further, the developing device 14 rotates in time for the development timing, and the magenta developing device 50 faces the photosensitive drum 11. A magenta toner image is sequentially formed and superimposed on the intermediate transfer belt 15 from the latent image exposed by the exposure device 13 based on the magenta image information. Similarly, cyan and black toner images are sequentially superimposed on the intermediate transfer belt 15 to complete the primary transfer.

  The secondary transfer roll 16 completes the primary transfer of the cyan toner image by the exposure device 13, and the toner image superimposed up to cyan is transferred to the secondary transfer portion (where the secondary transfer is performed by the secondary transfer roll 16). The intermediate transfer belt 15 is advanced (extruded) before the exposure for forming a black electrostatic latent image is started in the inter image after passing through. Then, the secondary transfer roll 16 is in contact (contact) with the intermediate transfer belt 15 to prepare for the secondary transfer. Further, the scraper 25 and the brush roll 26 are advanced with respect to the intermediate transfer belt 15 when the black portion is exposed and the cleaner portion (where the scraper 25 and the brush roll 26 are cleaned) is an inter-image. To do.

  On the other hand, the feed roll 32 is driven from the paper feed cassette 31 at a predetermined timing based on the control by the control unit 40, and the sheets are sequentially taken out and are fed one by one by the retard roll 33, to the registration roll 34. To reach. The registration roll 34 rotates in accordance with the secondary transfer timing in the secondary transfer unit, and functions to send the sheet to the secondary transfer unit at a predetermined timing.

  The sheet on which the toner image is transferred in the secondary transfer unit is conveyed to the fixing device 17. In the fixing device 17, the toner image on the paper is heated by the heat roll 35 and is pressed against the paper by the pressure roll 36 to be fixed. After that, it is output to the outside of the apparatus through the discharge roll 37 and is stored in the discharge tray 38 provided on the upper part of the main body 1. As described above, the image forming process for outputting one color print is completed.

FIG. 2 is a diagram for explaining the relationship between the photosensitive drum 11, the developing device 14 and the intermediate transfer belt 15 and explaining the relationship between the cleaning blade 18 and the toner recovery unit 19.
The photosensitive drum 11 shown in FIG. 2 includes a drum body 111 and a shaft portion 112. The drum body 111 is a tubular member having a diameter of about 47 mm, and a photosensitive layer whose resistance value is reduced by light irradiation is formed on the surface of the aluminum pipe. The shaft portion 112 receives a driving force of a motor (drive source) (not shown), and thereby the drum body 111 is rotationally driven. Detailed description thereof will be described later.

  Each of the developing devices 50 (Y, M, C, K) constituting the developing device 14 shown in FIG. 2 makes the distance between the developing roll 51 carrying the developer and the developing roll 51 and the photosensitive drum 11 constant. A tracking roll 52 for maintaining, and a supply auger 53 and an admix auger 54 for stirring the developer supplied to the developing roll 51 are provided. The developing roll 51 is made of, for example, a tubular member having a diameter of 16 mm, and a carrier contained in the developer is adsorbed by a magnetic force by a magnet roll (not shown) disposed inside, and developed on the surface of the developing roll 51. A magnetic brush of the agent is formed, and the toner adsorbed on the carrier is conveyed to the developing area of the photosensitive drum 11. The magnetic brush formed in this way is developed with the tip touching the surface of the photosensitive drum 11, so that the distance between the photosensitive drum 11 and the developing roll 51 is kept constant by the tracking roll 52. That is, the tracking roll 52 is formed to have a slightly larger radius (about 0.3 mm) than the developing roll 51 and to be coaxial with the developing roll 51 at both ends of the developing roll 51. As the tracking roll 52, a synthetic resin such as polyacetal is used.

  The intermediate transfer belt 15 shown in FIG. 2 is in contact with the lap range shown in FIG. 2 by the wrap-in roll 21 and the wrap-out roll 23 so as to cover the photosensitive drum 11. The lap range (wrap-shaped contact range) is an arc range formed at an angle of about 90 degrees at the peripheral edge of the photosensitive drum 11. The intermediate transfer belt 15 is an elastic belt and presses the photosensitive drum 11 with a relatively strong load. In addition, the intermediate transfer belt 15 itself can be configured to follow the drive of the photosensitive drum 11 that rotates clockwise in FIG. 2 without applying a driving force to the intermediate transfer belt 15 itself.

Next, the toner recovery unit 19 will be described.
The toner collecting unit 19 shown in FIG. 2 is opened in one direction, and a box-shaped housing unit 191 disposed so that the opening is located above, and a housing unit 191 so as to contact the surface of the photosensitive drum 11. And an upper seal member (seal member) 192 fixed to the head. Further, the toner collecting unit 19 is disposed in a toner reservoir mylar (sheet member, blocking member) 193 for covering the upper portion of the housing unit 191 and the housing unit 191, and is unidirectionally driven by a driving source (not shown). And an auger 194 for rotating and conveying the residual toner to a collecting device. It can be said that the cleaning blade 18 and the upper seal member 192 are arranged to face each other.

  The housing portion 191 holds the cleaning blade 18 so that the tip end portion 18 a of the cleaning blade 18 contacts the surface of the photosensitive drum 11. The position where the upper seal member 192 contacts the surface of the photosensitive drum 11 is upstream of the position where the tip 18a of the cleaning blade 18 contacts. In other words, in the present embodiment, the toner recovery unit 19 is disposed in a section where the surface of the rotating photosensitive drum 11 moves from top to bottom, and the upper seal member 192 is a cleaning blade. 18 is located above the tip 18a.

The cleaning blade 18 has a facing surface 18b that faces the surface of the photosensitive drum 11, and a facing surface 18c that is located on the side opposite to the facing surface 18b. The toner reservoir mylar 193 extends upward from the opposite surface 18 c of the cleaning blade 18.
Residual toner scraped off from the surface of the rotating photosensitive drum 11 by the front end portion 18a of the cleaning blade 18 includes the surface of the photosensitive drum 11, the opposite surface 18c of the cleaning blade 18 (on the front end portion 18a side) , an upper sealing member 192, the surface 193b of the toner reservoir Mylar 193 located on the surface side of the photosensitive drum 11, the area surrounded by (reservoir) is stored in a. More specifically, when toner accumulates in the region A, the weight of the toner acts on both the opposite surface 18c of the cleaning blade 18 and the surface 193b of the toner reservoir mylar 193. The toner reservoir Mylar 193 receives a force that moves in a direction away from the surface of the photosensitive drum 11, and the cleaning blade 18 receives a force that moves in a direction that approaches the surface of the photosensitive drum 11. These two forces are in opposite directions. By canceling out these two forces, the cleaning blade 18 can reduce the influence of the pressing force on the surface of the photosensitive drum 11 when the toner is excessively accumulated in the region A.
Note that the tip of the toner reservoir mylar 193 is in contact with the cleaning blade 18 so that residual toner does not spill from this gap. In addition, side seal members (not shown) are disposed at both ends of the cleaning blade 18 in the longitudinal direction (perpendicular to the paper surface).

  The residual toner stored in the region A serves as a lubricant for smoothly bringing the tip of the cleaning blade 18 into contact with the surface of the photosensitive drum 11. For this reason, damage to the tip of the cleaning blade 18 can be prevented, and the occurrence of abnormal noise and minute vibrations can be suppressed.

FIG. 3 is a schematic diagram for explaining the toner reservoir mylar 193 of the toner recovery unit 19.
The toner reservoir mylar 193 of the toner recovery unit 19 is a longitudinal member that extends along the axial direction of the photosensitive drum 11. In the toner reservoir Mylar 193, slits (discharge portions, openings) 193a are formed at predetermined intervals along the longitudinal direction. The slit 193 a is formed at an intermediate position in the direction perpendicular to the longitudinal direction of the toner reservoir Mylar 193. It can also be said that the slit 193 a is formed in a portion other than the tip portion where the toner reservoir Mylar 193 contacts the cleaning blade 18.

  Since the toner reservoir Mylar 193 is provided with the slit 193a, the excess toner remaining in the area A is transported by the auger 194 after falling from the slit 193a of the toner reservoir Mylar 193. Thus, an appropriate amount of residual toner is stored in the area A, and excessive storage of the residual toner in the area A can be avoided. Then, it is possible to avoid the residual toner stored in the region A from contacting the upper seal member 192. The opening area of the slit 193a only needs to be determined so that the residual toner does not contact the upper seal member 192 during normal rotation of the photosensitive drum 11.

FIG. 4 is a perspective view showing an end portion of the photosensitive drum 11. FIG. 4 shows a state in which the shaft portion 112 is slightly pulled out from the drum body 111 toward the front side of the drawing.
As shown in FIG. 4, the drum body 111 of the photosensitive drum 11 is provided at an end, and extends inward in the axial direction of the flange portion 111 a to which a driving force from a driving source (not shown) is supplied. Are provided with four drive transmission portions 111b formed at substantially equal intervals in the circumferential direction, and four slope portions 111c provided adjacent to the drive transmission portion 111b and extending outward in the axial direction. The drive transmission portion 111b and the slope portion 111c are separated by a predetermined distance α.

The shaft portion 112 of the photosensitive drum 11 includes an inner cylinder portion 112a that receives the drum body 111, and four protrusion portions 112b that are provided on the outer peripheral surface of the inner cylinder portion 112a so as to protrude in the center direction at an interval of approximately 90 degrees. And.
And the protrusion part 112b of the shaft part 112 is assembled so that it may be located between the drive transmission part 111b and the slope part 111c. For this reason, the protruding portion 112b of the shaft portion 112 presses the drive transmission portion 111b of the drum main body 111 or contacts the inclined surface portion 111c of the drum main body 111 depending on the direction in which the shaft portion 112 rotates.

  This will be further described. When the projecting portion 112b of the shaft portion 112 presses the drive transmission portion 111b of the drum main body 111, the drum main body 111 rotates in the arrow X direction. Further, when the projecting portion 112b of the shaft portion 112 contacts the slope portion 111c of the drum body 111, the drum body 111 rotates (reversely rotates) in the arrow Y direction. In addition, since the protrusion part 112b contacts the inclined surface part 111c at the time of reverse rotation, the impact force applied to the protrusion part 112b by the contact can be relieved.

  As described above, since the drive transmission portion 111b and the slope portion 111c are separated by a predetermined distance α, the shaft portion 112 has a play of a predetermined distance α with respect to the drum body 111. . Specifically, during the image forming operation, the shaft portion 112 receives a driving force from a driving source (not shown) so that the drum main body 111 rotates in the arrow X direction. The shaft portion 112 receives a driving force from a driving source (not shown) so that the drum body 111 rotates in the arrow Y direction during reverse rotation. When shifting from a state of normal rotation in the arrow X direction to a state of reverse rotation in the arrow Y direction, the drum body 111 starts to rotate after the shaft portion 112 has rotated by a predetermined distance α.

  The intermediate transfer belt 15 also includes a drive transmission system having the same structure as that shown in FIG. The play of the intermediate transfer belt 15 is smaller than the predetermined distance α in the photosensitive drum 11. Therefore, even if the photosensitive drum 11 and the intermediate transfer belt 15 are driven by the same drive source, the reverse rotation amount of the photosensitive drum 11 is the reverse rotation amount of the intermediate transfer belt 15 during reverse rotation. Smaller than.

FIG. 5 is a flowchart for explaining the operation from the start to the end of the image forming operation.
When the control unit 40 detects a signal indicating that a start switch (not shown) provided on a control panel (not shown) is turned on, a predetermined image forming process is executed and a copy operation is started (step 101). Then, the control unit 40 drives the photosensitive drum 11 to rotate along the X direction (see FIG. 2) which is the forward direction (step 102), and the toner image formed on the photosensitive drum 11 is placed on the paper. Transfer.

  When the control unit 40 detects a copy operation end signal indicating that the copy operation has ended (step 103), the normal rotation of the photosensitive drum 11 is stopped (step 104). Thereafter, the control unit 40 sets the photosensitive drum 11 to a minute amount (the amount of movement of the surface of the photosensitive drum 11) in the Y direction (refer to FIG. 2) opposite to the X direction during the normal image forming operation. The rotation of the photosensitive drum 11 is stopped (step 106).

Due to the reverse rotation of the photosensitive drum 11, the residual toner or paper dust sandwiched between the tips of the cleaning blade 18 moves while adhering to the surface of the photosensitive drum 11 when the photosensitive drum 11 rotates in the reverse direction. 18 is reliably removed from the tip.
Further, since the residual toner in the region A is not excessively stored by the slit 193a of the toner reservoir Mylar 193, the residual toner can be configured not to contact the upper seal member 192. For this reason, it is possible to prevent the residual toner in the region A from being ejected during reverse rotation.

In this embodiment, a so-called four-cycle method is used in which a single photosensitive drum is used to obtain a color image by rotating the photosensitive drum four times. The present invention can also be applied to a so-called tandem type image forming apparatus in which the photosensitive drums are arranged in series.
In the above embodiment, a method using a known intermediate transfer belt has been described. However, a method using an intermediate transfer roll or a method for transferring a toner image directly from a photosensitive drum to a recording medium without using an intermediate transfer member. Of course, it is also possible to use the method of making it happen.

1 is a diagram illustrating an overall configuration of an image forming apparatus to which the exemplary embodiment is applied. FIG. 4 is a diagram for explaining a relationship between a photosensitive drum, a developing device, and an intermediate transfer belt, and a relationship between a cleaning blade and a toner recovery unit. FIG. 6 is a schematic diagram illustrating a toner accumulation mylar of a toner recovery unit. It is a perspective view which shows the one end part of a photoconductive drum. 6 is a flowchart for explaining an operation from the start to the end of an image forming operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Photosensitive drum, 111 ... Drum main body, 112 ... Shaft part, 15 ... Intermediate transfer belt, 18 ... Cleaning blade, 18a ... Tip part, 18b ... Opposite surface, 18c ... Opposite surface, 19 ... Toner collection part, 191 ... Housing part, 192 ... upper seal member, 193 ... toner reservoir mylar, 193a ... slit, 193b ... surface, 194 ... auger

Claims (10)

A cleaning device for cleaning the surface of an image carrier that carries a toner image,
The image bearing member has a facing surface facing the surface and an opposite surface located on a side opposite to the facing surface, and has a tip portion that contacts the surface of the image bearing member, and adheres to the surface. A cleaning blade that removes the waste toner being removed by the tip,
The image carrier has a storage portion that extends upward from the opposite surface of the cleaning blade and has a surface located on the surface side of the image carrier, and stores waste toner removed by the tip portion of the cleaning blade. A surface located on the surface side of the image carrier together with the surface of the cleaning blade and the opposite surface of the cleaning blade , and the weight of the waste toner that is stored in the storage portion and acts on the opposite surface of the cleaning blade A sheet member that also acts on the surface located on the surface side of the image carrier;
A discharge unit disposed so as to be positioned above the tip of the cleaning blade, and discharging a part of waste toner stored in the storage unit;
Including cleaning device.   A seal member positioned above the storage unit, wherein the discharge unit discharges the waste toner from the storage unit so that the waste toner stored in the storage unit does not contact the seal member; The cleaning apparatus according to claim 1.   The cleaning device according to claim 1, wherein the discharge unit is configured by an opening formed in the sheet member.   The cleaning apparatus according to claim 1, further comprising a housing portion to which the cleaning blade and the sheet member are attached, and waste toner discharged through the discharge portion falls into the housing portion.   2. The image bearing member according to claim 1, wherein the image carrier rotates in one direction to perform an image forming operation and can rotate in a direction opposite to the one direction when the image forming operation is not performed. Cleaning device. A process cartridge that is detachably attached to the image forming apparatus main body,
A housing part;
A cleaning blade attached to the housing portion and having a tip portion that contacts the surface of an image carrier that carries a toner image in the main body of the image forming apparatus and removes waste toner adhering to the surface;
Extending upward from the opposite surface of the cleaning blade located on the opposite side of the opposing surface of the cleaning blade facing the surface of the image carrier, and having a surface located on the surface side of the image carrier; Waste toner removed by the tip is dammed to a surface formed on the surface side of the image carrier, the surface of the image carrier and the opposite surface of the cleaning blade , and A blocking member in which the weight of the waste toner which is blocked and acts on the opposite surface of the cleaning blade also acts on the surface located on the surface side of the image carrier;
An opening formed in a portion other than the portion of the cleaning blade in contact with the tip of the cleaning blade;
Containing process cartridge.   It further includes a seal member attached to the housing portion so as to face the cleaning blade, and a part of the waste toner is removed from the opening so that the waste toner blocked by the blocking member does not contact the seal member. The process cartridge according to claim 6, wherein the process cartridge is discharged. An image forming apparatus including an image carrier that rotates in one direction to perform an image forming operation and can rotate in a direction opposite to the one direction when the image forming operation is not performed.
The image bearing member has a facing surface facing the surface and an opposite surface located on a side opposite to the facing surface, and has a tip portion that contacts the surface of the image bearing member and adheres to the surface. A cleaning blade that removes and cleans the waste toner being removed by the tip,
A storage portion that extends upward from the opposite surface of the cleaning blade and has a surface located on a surface side of the image carrier, and stores waste toner removed from the surface of the image carrier by the cleaning blade; A surface located on the surface side of the image carrier is formed together with the surface of the image carrier and the opposite surface of the cleaning blade , and is stored in the reservoir and acts on the opposite surface of the cleaning blade. A sheet member in which the weight of the waste toner also acts on the surface located on the surface side of the image carrier;
A discharge portion that is located above the tip portion of the cleaning blade and discharges a part of the waste toner stored in the storage portion;
An image forming apparatus including:   A seal member positioned above the storage unit, wherein the discharge unit discharges the waste toner from the storage unit so that the waste toner stored in the storage unit does not contact the seal member; The image forming apparatus according to claim 8.   The image forming apparatus according to claim 8, wherein the discharge unit includes an opening formed in the sheet member.

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