JP6120802B2 - Cleaning device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a cleaning apparatus including a cleaning roller that polishes the surface of an image carrier, and an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multi-function machine including the same.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, or a FAX, a powdered developer (hereinafter referred to as toner) is mainly used, and an electrostatic formed on an image carrier such as a photosensitive drum. In general, the latent image is visualized with toner in the developing device, and the toner image is transferred onto a recording medium, and then a fixing process is performed. In such an image forming apparatus, a cleaning device for removing residual toner on the surface of the photosensitive drum is mounted.

  Further, the surface of the photosensitive drum is usually made of amorphous silicon (α-Si) or the like, but when an amorphous silicon photosensitive member is used as the photosensitive member, the charging device discharges on the photosensitive member surface. It is known that discharge products easily adhere to the surface. When this discharge product absorbs moisture, the electrical resistance on the surface of the photoreceptor is lowered, causing a problem of image flow that disturbs the electrostatic latent image, which may affect the image quality.

  Therefore, in order to remove deposits such as discharge products on the surface of the photosensitive drum, a cleaning roller is provided in the cleaning device, the cleaning roller is brought into contact with the photosensitive drum, and residual toner on the photosensitive drum is collected. A part of the collected toner is supplied to the surface of the photosensitive drum, and further, the surface of the photosensitive drum is polished using a toner layer on the surface of the cleaning roller. In order to polish the photosensitive drum satisfactorily, it is necessary to make the rubbing force by the toner constant. Therefore, a toner layer thickness regulating roller is provided to regulate the thickness of the toner layer on the surface of the cleaning roller. .

  The cleaning device is provided with a cleaning blade for scraping off the residual toner on the surface of the photosensitive drum, and a toner receiving member for receiving the residual toner scraped off by the cleaning blade and the toner collected by the cleaning roller. There is something that is. The toner layer thickness regulating roller regulates the thickness of the toner layer on the surface of the cleaning roller by supplying the toner accumulated in the toner receiving member to the cleaning roller or returning the toner collected from the cleaning roller to the toner receiving member. .

  Such a cleaning device including a toner layer thickness regulating roller that regulates the thickness of the toner layer on the surface of the cleaning roller and a toner receiving member that is disposed below the cleaning roller and receives toner is disclosed in, for example, Patent Document 1 and Patent It is disclosed in Document 2.

  Patent Document 1 discloses a cleaning device in which a toner receiving member is disposed below a cleaning roller, and a toner layer thickness regulating roller is disposed between the cleaning roller and the toner receiving member.

  Patent Document 2 discloses a cleaning device in which a toner receiving member is disposed in the vicinity of the lowermost portion of the cleaning roller, and a toner layer thickness regulating roller is disposed on the side of the toner receiving member or the cleaning roller.

JP 2011-154220 A JP 2011-150095 A

  However, in the cleaning device disclosed in Patent Document 1, since the toner layer thickness regulating roller is always immersed (contacted) with the toner of the toner receiving member, a large amount of toner is supplied from the photosensitive drum to the cleaning device. When the amount of toner on the toner receiving member increases, the amount of toner supplied from the toner receiving member to the toner layer thickness regulating roller increases. For this reason, there is a problem that the thickness of the toner layer on the surface of the cleaning roller may become too large.

  Further, in the cleaning device of Patent Document 2, since the toner layer thickness regulating roller is separated from the toner of the toner receiving member, the toner supplied from the photosensitive drum to the cleaning device is reduced and the toner of the toner layer thickness regulating roller is reduced. When the amount of toner decreases, the force to remove the toner on the surface of the cleaning roller increases. For this reason, there is a problem that the thickness of the toner layer on the surface of the cleaning roller may be too small.

  Further, in the cleaning devices of Patent Document 1 and Patent Document 2, toner accumulated on the toner receiving member is difficult to be discharged due to the presence of the toner layer thickness regulating roller and the cleaning roller on the toner receiving member. For this reason, the toner on the toner receiving member aggregates, and the toner tends to accumulate up to the upper end of the cleaning blade. As a result, the toner pressure applied to the upper end of the cleaning blade increases, and the external additive of toner adheres to the photosensitive drum, and a vertical spot pattern (hereinafter referred to as a dash mark) may occur in the output image. There is a problem that there is.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to perform cleaning that can stably polish an image carrier while suppressing dash marks in an output image. An apparatus and an image forming apparatus including the same are provided.

  To achieve the above object, the cleaning device of the present invention comprises a cleaning roller that rotatably contacts an image carrier and polishes the surface of the image carrier using toner, and a surface of the image carrier relative to the cleaning roller. A scraping member that scrapes off residual toner on the surface of the image carrier, a toner layer thickness regulating roller that regulates the thickness of the toner layer on the surface of the cleaning roller, and a cleaning roller that is directly below the cleaning roller. And a toner receiving member having a toner receiving surface that receives the toner scraped off from the surface of the image carrier by the scraping member, and the toner layer thickness regulating roller is located immediately below the cleaning roller. A first position in contact with the outer peripheral surface of the toner and the toner of the toner receiving member, and an outer periphery of the cleaning roller And a second position not in contact with the toner of the contact toner receiving member to be chosen disposed.

  According to the present invention, the toner layer thickness regulating roller is in contact with the outer peripheral surface of the cleaning roller and the toner of the toner receiving member and the outer surface of the cleaning roller and does not contact the toner of the toner receiving member. It is selectively arranged at the second position. Thus, when the amount of toner supplied from the image carrier to the cleaning device is small, the toner layer thickness regulating roller is disposed at the first position, and when the amount of toner supplied from the image carrier to the cleaning device is large, the toner is By disposing the layer thickness regulating roller at the second position, the thickness of the toner layer on the surface of the cleaning roller can be regulated within a predetermined range. As a result, the image carrier can be stably polished.

  Further, when the toner layer thickness regulating roller is arranged at the second position, the side of the toner receiving surface is opened, so that it is possible to prevent the toner accumulated on the toner receiving surface from being easily discharged. . For this reason, the toner on the toner receiving member can be prevented from aggregating, so that the toner can be prevented from collecting up to the upper end of the scraping member. Accordingly, it is possible to suppress the toner pressure applied to the upper end of the scraping member from being increased, and it is possible to suppress the occurrence of a dash mark in the output image due to the toner external additive being fixed to the image carrier. it can.

1 is a cross-sectional view schematically showing a structure of an image forming apparatus including a cleaning device according to an embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a state in which the toner layer thickness regulating roller of the cleaning device according to the embodiment of the present invention is disposed at a first position. FIG. 3 is an exploded perspective view around a cleaning roller and a toner layer thickness regulating roller of the cleaning device according to the embodiment of the present invention. It is sectional drawing which showed the state by which the toner layer thickness control roller of the cleaning apparatus of one Embodiment of this invention was arrange | positioned in the 2nd position. It is the top view which showed the structure of the cleaning apparatus of one Embodiment of this invention. It is the top view which showed the state which the lever part of the cleaning apparatus of one Embodiment of this invention rotated to the left side. It is the top view which showed the state which the lever part of the cleaning apparatus of one Embodiment of this invention rotated to the right side.

  Embodiments of the present invention will be described below with reference to the drawings.

  With reference to FIGS. 1 to 7, an image forming apparatus 100 including cleaning devices 5a, 5b, 5c, and 5d according to an embodiment of the present invention will be described.

  An image forming apparatus 100 according to an embodiment of the present invention is a tandem type color printer, and four image forming units Pa, Pb, Pc, and Pd are disposed on the upstream side in the transport direction (FIG. 1). In FIG. These image forming portions Pa to Pd are provided corresponding to images of four different colors (magenta, cyan, yellow, and black), and magenta, cyan, and yellow are respectively subjected to charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  In these image forming portions Pa to Pd, photosensitive drums (image bearing members) 1a, 1b, 1c and 1d having a photosensitive layer made of amorphous silicon for carrying visible images (toner images) of the respective colors are arranged. Further, an intermediate transfer belt 8 that rotates in the clockwise direction in FIG. 1 is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1a to 1d are sequentially transferred (primary transfer) onto the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1a to 1d, and then the secondary transfer roller. 9 is transferred onto the paper P at one time (secondary transfer), and further fixed on the paper P in the fixing unit 7 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d in the counterclockwise direction in FIG.

  The paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the apparatus, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt having no seam is mainly used. A blade-shaped belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed downstream of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure unit 4 for exposing the toner, the developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning devices 5a, 5b, 5c and 5d are provided.

  When image data is input from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated by the exposure unit 4 to each photosensitive member. Electrostatic latent images corresponding to image signals are formed on the drums 1a to 1d. Each of the developing devices 3a to 3d is filled with a predetermined amount of magenta, cyan, yellow, and black toner by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing devices 3a to 3d and electrostatically attached, whereby a toner image corresponding to the electrostatic latent image formed by exposure from the exposure unit 4 is formed. It is formed.

  After an electric field is applied to the intermediate transfer belt 8 at a predetermined transfer voltage, magenta, cyan, yellow, and black toner images on the photosensitive drums 1a to 1d are transferred to the intermediate transfer belt 8 by the primary transfer rollers 6a to 6d. Primary transferred onto. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning devices 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched over a transport roller 10 on the upstream side, a drive roller 11 on the downstream side, and a tension roller 20, and the intermediate transfer belt 8 is rotated along with the rotation of the drive roller 11 by a drive motor (not shown). When the rotation in the clockwise direction is started, the paper P is conveyed from the registration roller pair 12b to the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and the nip portion with the intermediate transfer belt 8 ( The full color image is secondarily transferred onto the paper P at the secondary transfer nip portion). The paper P on which the toner image is transferred is conveyed to the fixing unit 7.

  The sheet P conveyed to the fixing unit 7 is heated and pressurized when passing through the nip portion (fixing nip portion) of the fixing roller pair 13 to fix the toner image on the surface of the sheet P, and a predetermined full-color image is formed. It is formed. The paper P on which the full-color image is formed is distributed in the transport direction by the branching section 14 that branches in a plurality of directions. When an image is formed only on one side of the paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller 15.

  On the other hand, when forming images on both sides of the paper P, a part of the paper P that has passed through the fixing unit 7 is once projected from the discharge roller pair 15 to the outside of the apparatus. Thereafter, the paper P is distributed to the paper conveyance path 18 by the branching section 14 by rotating the discharge roller pair 15 in the reverse direction, and is re-conveyed to the registration roller pair 12b with the image surface reversed. Then, after the next image formed on the intermediate transfer belt 8 is transferred to the surface of the paper P where the image is not formed by the secondary transfer roller 9 and conveyed to the fixing unit 7 to fix the toner image, The paper is discharged to the discharge tray 17 through the discharge roller pair 15.

  Next, the cleaning devices 5a to 5d will be described. Here, the cleaning device 5a will be described, but the description is omitted because 5b to 5d have the same configuration and operation.

  As shown in FIG. 2, the cleaning device 5 a includes a cleaning roller 21, a toner layer thickness regulating roller 22, a cleaning blade (scraping member) 23, a toner receiving member 24, a toner discharge screw 25, and a housing 26. In FIGS. 2 and 4, the toner is drawn with black circles.

  The cleaning roller 21 is configured by forming a foamed material such as EPDM rubber around a metal shaft portion 21a. The cleaning roller 21 rotatably contacts the photosensitive drum 1a, collects residual toner on the photosensitive drum 1a, and supplies a part of the collected toner to the surface of the photosensitive drum 1a. Further, the cleaning roller 21 polishes the surface of the photosensitive drum 1 a using a toner layer on the surface (outer peripheral surface) of the cleaning roller 21.

  The toner layer thickness regulating roller 22 is a foamed sponge roller configured by forming a foam such as urethane around a metal shaft portion 22a. Further, the toner layer thickness regulating roller 22 is configured to be rotatable, and collects a part of the toner on the surface of the cleaning roller 21 and also removes a part of the collected toner and the toner of the toner receiving member 24. By supplying (returning) to the surface of the toner, the thickness of the toner layer on the surface of the cleaning roller 21 is regulated.

  As shown in FIG. 3, the shaft portion 21 a of the cleaning roller 21 and the shaft portion 22 a of the toner layer thickness regulating roller 22 are rotatably supported by a common bearing member 30. Further, the shaft portion 21 a of the cleaning roller 21 is rotatably supported by a bearing member 31 disposed outside the bearing member 30.

  The bearing member 31 has a bearing hole 31 a into which the shaft portion 21 a of the cleaning roller 21 is inserted, and a bearing hole 31 b into which a shaft portion (not shown) provided in the housing 26 is inserted. The bearing member 31 is urged by an urging member (not shown), thereby rotating around the bearing hole 31b toward the photosensitive drum 1a. Accordingly, the cleaning roller 21 is pressed with a predetermined force against the photosensitive drum 1a.

  The bearing member 30 includes a bearing hole 30a into which the shaft portion 21a of the cleaning roller 21 is inserted, a bearing hole 30b into which the shaft portion 22a of the toner layer thickness regulating roller 22 is inserted, and a lever portion 30c extending upward. . Since the shaft portion 21a and the shaft portion 22a are pivotally supported by the common bearing member 30, the distance between the shaft portion 21a and the shaft portion 22a is kept constant.

  As the lever portion 30c is rotated about the shaft portion 21a of the cleaning roller 21, the toner layer thickness regulating roller 22 is also rotated about the shaft portion 21a. Specifically, the toner layer thickness regulating roller 22 has a first position (position shown in FIG. 2) just below the cleaning roller 21 and in contact with the outer peripheral surface of the cleaning roller 21 and the toner of the toner receiving member 24. The second position (position shown in FIG. 4) is selected and disposed in contact with the outer peripheral surface of the cleaning roller 21 and not in contact with the toner of the toner receiving member 24.

  As shown in FIG. 2, the cleaning blade 23 is made of, for example, polyurethane rubber, and is disposed downstream of the cleaning roller 21 in the rotation direction of the surface of the photosensitive drum 1a, and scrapes off residual toner on the surface of the photosensitive drum 1a. .

  The toner receiving member 24 is made of, for example, SUS, and is disposed at a position directly below the cleaning roller 21. The toner receiving member 24 receives the toner scraped off from the surface of the photosensitive drum 1 a by the cleaning blade 23 and the toner collected by the cleaning roller 21. It has a receiving surface 24a. The toner receiving surface 24a corresponds to an area (the locus of the outer peripheral surface of the toner layer thickness regulating roller 22) that passes when the toner layer thickness regulating roller 22 rotates about the shaft portion 21a of the cleaning roller 21. It is concavely curved.

  The toner discharge screw 25 is a rotary member, and discharges waste toner that has fallen from the toner receiving surface 24a to the outside of the apparatus from a toner discharge port (not shown) provided on the bottom surface of the housing 26.

  As shown in FIG. 5, an opening 26 a for projecting the lever portion 30 c of the bearing member 30 upward is formed on the upper surface of the housing 26.

  As shown in FIG. 6, a lever operation plate 32 is disposed above the housing 26. A lever insertion hole 32a is formed in the lever operation plate 32 at a position corresponding to the lever portion 30c. The lever insertion hole 32a is formed to be inclined with respect to the axial direction of the cleaning roller 21 (the vertical direction in FIG. 6). Accordingly, when the lever operation plate 32 is moved to one side (lower side in FIG. 6) as shown in FIG. 6, the lever portion 30c rotates to the left side, and the lever operation plate 32 is moved to the other side as shown in FIG. When moved to the side (upper side in FIG. 7), the lever portion 30c rotates to the right. The lever operation plate 32 can be easily moved using, for example, a solenoid (not shown).

  Next, the operation of removing the deposits such as toner and discharge products remaining on the surface of the photosensitive drum 1a by the cleaning device 5a will be described.

  The residual toner scraped off from the surface of the photosensitive drum 1 a by the cleaning blade 23 and the toner collected by the cleaning roller 21 fall due to gravity and accumulate on the toner receiving member 24.

  Here, when the printing rate of the image to be printed is large, the toner supplied from the developing device 3a to the surface of the photosensitive drum 1a increases, and the toner collected by the cleaning roller 21 also increases. In this case, since the toner on the surface of the toner layer thickness regulating roller 22 increases, the amount of toner supplied to the cleaning roller 21 is increased compared to the toner collected from the cleaning roller 21 by the toner layer thickness regulating roller 22. The thickness of the toner layer on the surface may become too large.

  For this reason, in the cleaning device 5a of the present embodiment, in order to prevent the thickness of the toner layer on the surface of the cleaning roller 21 from becoming too large, the printing rate is equal to or greater than a predetermined value (for example, the average printing rate of 100 sheets). Is 5% or more), the lever operation plate 32 is moved to the other side (upper side in FIG. 7) as shown in FIG. As a result, the lever portion 30c rotates to the right, and the toner layer thickness regulating roller 22 moves to the second position as shown in FIG. Since the toner layer thickness regulating roller 22 does not come into contact with the toner on the toner receiving member 24, the amount of toner supplied to the cleaning roller 21 is reduced, and the thickness of the toner layer on the surface of the cleaning roller 21 is maintained within a predetermined range.

  On the other hand, when the printing rate of the image to be printed is small, the amount of toner supplied from the developing device 3a to the surface of the photosensitive drum 1a is reduced, and the amount of toner collected by the cleaning roller 21 is also reduced. In this case, since the toner on the surface of the toner layer thickness regulating roller 22 is reduced, the toner supplied to the cleaning roller 21 is reduced compared to the toner collected from the cleaning roller 21 by the toner layer thickness regulating roller 22. The thickness of the toner layer on the surface may become too small.

  For this reason, in the cleaning device 5a of the present embodiment, in order to prevent the thickness of the toner layer on the surface of the cleaning roller 21 from becoming too small, the printing rate is less than a predetermined value (for example, the average printing rate of 100 sheets). Is less than 5%), the lever operation plate 32 is moved to one side (lower side in FIG. 6) as shown in FIG. As a result, the lever portion 30c rotates to the left, and the toner layer thickness regulating roller 22 moves to the first position as shown in FIG. Since the toner layer thickness regulating roller 22 comes into contact with the toner on the toner receiving member 24, the amount of toner supplied to the cleaning roller 21 increases, and the thickness of the toner layer on the surface of the cleaning roller 21 is maintained within a predetermined range.

  Note that the printing rate of an image to be printed is calculated for each color by, for example, a calculation unit (not shown). Further, the operation of removing the deposits such as toner remaining on the surface of the photosensitive drum 1 a is controlled by a control unit (CPU) (not shown) provided in the image forming apparatus 100.

  In the present embodiment, as described above, the toner layer thickness regulating roller 22 is configured such that when the amount of toner supplied from the photosensitive drums 1a to 1d to the cleaning devices 5a to 5d is small, the outer peripheral surface of the cleaning roller 21 and the toner receiving member. It is arranged at the first position (position shown in FIG. 2) in contact with the 24 toner. Further, the toner layer thickness regulating roller 22 contacts the outer peripheral surface of the cleaning roller 21 and does not contact the toner of the toner receiving member 24 when a large amount of toner is supplied from the photosensitive drums 1a to 1d to the cleaning devices 5a to 5d. It arrange | positions in the 2nd position (position shown in FIG. 4). Thereby, since the thickness of the toner layer on the surface of the cleaning roller 21 can be regulated within a predetermined range, the photosensitive drums 1a to 1d can be stably polished.

  Further, when the toner layer thickness regulating roller 22 is disposed at the second position, the side of the toner receiving surface 24a is opened, so that it is possible to prevent the toner accumulated on the toner receiving surface 24a from being easily discharged. be able to. For this reason, the toner on the toner receiving member 24 can be prevented from aggregating, so that the toner can be prevented from accumulating up to the upper end of the cleaning blade 23. Accordingly, it is possible to suppress the toner pressure applied to the upper end of the cleaning blade 23 from being increased, and it is possible to suppress the occurrence of a dash mark in the output image due to the toner external additive being fixed to the photosensitive drums 1a to 1d. can do.

  In addition, as described above, the common bearing member 30 that supports the shaft portion 21a of the cleaning roller 21 and the shaft portion 22a of the toner layer thickness regulating roller 22 is provided, and the toner layer thickness regulating roller 22 is a cleaning roller. By rotating about the shaft portion 21a of the shaft 21, it is selectively arranged at the first position and the second position. Thereby, when the toner layer thickness regulating roller 22 moves between the first position and the second position, fluctuations in the contact pressure of the toner layer thickness regulating roller 22 with respect to the cleaning roller 21 can be suppressed. The photosensitive drums 1a to 1d can be more stably polished. Further, by supporting the shaft portion 21 a of the cleaning roller 21 and the shaft portion 22 a of the toner layer thickness regulating roller 22 by the common bearing member 30, it is possible to suppress an increase in the number of parts.

  Further, as described above, the toner receiving surface 24a is a region through which the toner layer thickness regulating roller 22 rotates when it rotates about the shaft portion 21a of the cleaning roller 21 (the locus of the outer circumferential surface of the toner layer thickness regulating roller 22). ) To be curved. As a result, the contact state of the toner layer thickness regulating roller 22 with respect to the toner of the toner receiving member 24 can be prevented from changing around the first position, so that the photosensitive drums 1a to 1d are more stably polished. be able to.

  Further, as described above, the toner layer thickness regulating roller 22 is a foamed sponge roller. This makes it possible to achieve both the function of holding toner and supplying it to the cleaning roller 21 and the function of ejecting excess toner when the cleaning roller 21 is compressed and released.

  As described above, when the amount of toner supplied from the developing devices 3a to 3d to the photosensitive drums 1a to 1d is large, the amount of toner supplied from the photosensitive drums 1a to 1d to the cleaning devices 5a to 5d increases. When the amount of toner supplied from the developing devices 3a to 3d to the photosensitive drums 1a to 1d is small, the amount of toner supplied from the photosensitive drums 1a to 1d to the cleaning devices 5a to 5d decreases. Therefore, the cleaning roller is selectively disposed at the first position and the second position based on the toner supply amount from the developing devices 3a to 3d to the photosensitive drums 1a to 1d. The thickness of the toner layer on the surface 21 can be easily regulated within a predetermined range.

  Further, as described above, when the printing rate is less than the predetermined value, the amount of toner supplied from the developing devices 3a to 3d to the photosensitive drums 1a to 1d decreases, and when the printing rate is equal to or higher than the predetermined value, the developing device 3a. The amount of toner supplied from -3d to the photosensitive drums 1a-1d increases. For this reason, the cleaning roller 21 is arranged by disposing the toner layer thickness regulating roller 22 at the first position when the printing rate is less than a predetermined value and at the second position when the printing rate is equal to or higher than the predetermined value. The thickness of the toner layer on the surface can be more easily regulated within a predetermined range.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a color printer as shown in FIG. 1 has been shown, the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming apparatuses including a cleaning device including a cleaning roller, such as a monochrome printer, a color copying machine, a monochrome copying machine, a digital multifunction machine, and a facsimile machine.

  In the above embodiment, the toner layer thickness regulating roller 22 is selectively disposed only at the first position and the second position. However, the present invention is not limited to this. For example, the toner layer thickness regulating roller 22 may be selectively arranged at a first position, a second position, and a third position between the first position and the second position.

  In the above-described embodiment, the movement of the toner layer thickness regulating roller 22 (operation of the lever portion 30c) is automatically performed using a solenoid or a control unit. However, the movement of the toner layer thickness regulating roller 22 (lever) The operation of the unit 30c) may be performed manually by the user.

  Further, the movement of the toner layer thickness regulating roller 22 (operation of the lever portion 30c) can be simultaneously performed by all the cleaning devices 5a to 5d. In this case, if all the lever operation plates 32 are connected by the connecting member, all the toner layer thickness regulating rollers 22 can be easily moved using one solenoid or the like. However, since the printing rate is usually different for each color, it is preferable to move the toner layer thickness regulating roller 22 for each of the cleaning devices 5a to 5d.

1a to 1d Photosensitive drum (image carrier)
3a to 3d Developing device 5a to 5d Cleaning device 21 Cleaning roller 21a Shaft portion 22 Toner layer thickness regulating roller 22a Shaft portion 23 Cleaning blade (scraping member)
24 toner receiving member 24a toner receiving surface 30 bearing member 100 image forming apparatus

Claims (7)

A cleaning roller that rotatably contacts the image carrier and polishes the surface of the image carrier using toner;
A scraping member disposed on the downstream side in the rotational direction of the surface of the image carrier with respect to the cleaning roller, and scraping off residual toner on the surface of the image carrier;
A toner layer thickness regulating roller for regulating the thickness of the toner layer on the surface of the cleaning roller;
A toner receiving member disposed at a position directly below the cleaning roller and having a toner receiving surface for receiving the toner scraped off from the surface of the image carrier by the scraping member;
With
The toner layer thickness regulating roller is located immediately below the cleaning roller and in contact with the outer peripheral surface of the cleaning roller and the toner of the toner receiving member, and in contact with the outer peripheral surface of the cleaning roller. A cleaning device, wherein the cleaning device is selectively disposed at a second position where the member does not contact the toner. A common bearing member that supports the shaft portion of the cleaning roller and the shaft portion of the toner layer thickness regulating roller;
2. The toner layer thickness regulating roller is selectively disposed at the first position and the second position by rotating around a shaft portion of the cleaning roller. Cleaning device.   3. The toner receiving surface according to claim 2, wherein the toner receiving surface is curved so as to correspond to a region through which the toner layer thickness regulating roller passes when rotating around the shaft portion of the cleaning roller. Cleaning device.   The cleaning device according to claim 1, wherein the toner layer thickness regulating roller is a foamed sponge roller.   An image forming apparatus comprising the cleaning device according to claim 1. A developing device for supplying toner to the image carrier;
The toner layer thickness regulating roller is selectively disposed at the first position and the second position based on a supply amount of toner from the developing device to the image carrier. The image forming apparatus according to 5. A calculation unit for calculating a printing rate of an image to be printed;
The toner layer thickness regulating roller is disposed at the first position when the printing rate calculated by the calculation unit is less than a predetermined value, and is placed at the second position when the printing rate is equal to or greater than a predetermined value. The image forming apparatus according to claim 6, wherein the image forming apparatus is disposed.

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