Cleaning device and image forming apparatus

Abstract

To prevent toner remaining on a brush roller from flowing out to the outside of a cleaning device.SOLUTION: A cleaning device 50 has a brush roller 54 and a housing 53. The housing 53 has: a scattering prevention part 58 provided to be in contact with the brush roller 54; a shield part 59 provided on the downstream side of a contact part between the scattering prevention part 58 and the brush roller 54 in a direction of rotation of the brush roller 54 and on the upstream side of a contact part between the brush roller 54 and an image carrier 31; and a receiving part 62 receiving toner released from the brush roller 54 passing through the scattering prevention part 58. The shield part 59 is provided continuously at least from a position P3 of the brush roller 54 intersecting a tangent L1 of the scattering prevention part to a second position P2 closest to a rotation center X of the brush roller 54. A distance from the rotation center X to the second position P2 is larger than a distance from the rotation center X to a first position P1 of the scattering prevention part 58 closest to the rotation center X. The receiving part 62 is provided below the first position P1.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cleaning device used in an image forming apparatus such as a copying machine, printer, facsimile machine, or multifunction machine equipped with two or more of the functions of electrophotography or electrostatic recording, and to an image forming apparatus equipped with the same. [Background technology]

[0002] Conventionally, in image forming apparatuses such as electrophotographic copying machines, a toner image formed on an image carrier is transferred to a transferee. For example, a toner image formed on a photosensitive drum as an image carrier is transferred to a recording material such as paper, or to an intermediate transfer belt. Also, for example, a toner image formed on an intermediate transfer belt as an image carrier is transferred to a recording material such as paper. Then, toner that is not transferred to the transferee and remains on the image carrier (transfer residual toner) is removed from the image carrier by a cleaning device and collected.

[0003] One such cleaning device is an electrostatic cleaning type. This cleaning device has a rotatable conductive elastic roller having a conductive elastic layer on its outer periphery. For example, a brush roller having a brush portion (e.g., a fur brush) formed of elastic conductive fibers as an elastic layer is used as the elastic roller. This cleaning device brings the brush roller into contact with the surface of the image carrier, applies a predetermined bias to the brush roller while rotating the brush roller, and electrically moves the toner from the image carrier to the brush roller, thereby removing the toner from the surface of the image carrier. In particular, when the image carrier has an elastic layer such as a rubber layer on its surface, or when a long life of the image carrier is required, a cleaning device of the electrostatic cleaning type is preferably used.

[0004] In the electrostatic cleaning type cleaning device, the toner collected by the brush roller from the image carrier is detached from the brush roller and temporarily stored in a storage unit in the cleaning device. The toner is detached from the brush roller by physically scraping it off with a scraping member in contact with the brush roller, or by applying a bias to a collection member such as a metal roller (bias roller) in contact with the brush roller to electrically attract and move the toner. In order to store the toner collected by the brush roller in a specified area in the cleaning device without scattering it, a method of electrically attracting and moving the toner by applying a bias to the collection member is preferably used. The toner stored in the storage unit in the cleaning device is transported by a transport member such as a transport screw and discharged to the outside of the cleaning device, and is collected in a collected toner container provided in the image forming device through a transport path provided in the image forming device.

[0005] However, because the brush roller rotates, air flows are formed inside and outside the cleaning device, and as a result, toner scattered inside the cleaning device may scatter outside the cleaning device, contaminating the inside of the image forming device with toner, which may cause image defects.

[0006] In Patent Document 1, a configuration is proposed in which a scattering prevention part that penetrates into the fur brush is provided in a cleaning container of the cleaning device, and the scattering prevention part shields the bias roller from the outside of the cleaning device. With this configuration, it is possible to prevent toner scattered inside the cleaning device from flowing out to the outside of the cleaning device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-228555 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, when the toner on the image carrier is collected by the brush roller, or when the toner is transferred from the brush roller to the collection member, the charge of the toner may become close to zero or the polarity may be reversed. Such toner may not be transferred to the collection member and may remain on the brush roller. The toner remaining on the brush roller has a weak electrical binding force and is in a state in which it is easy to separate from the brush roller. If the scattering prevention part enters the brush roller in this state, the following occurs. That is, the brush part of the brush roller (for example, a fur brush) abuts against the scattering prevention part and deforms, and when it passes through the scattering prevention part, it exhibits a behavior of elastically restoring to its original state. Due to the behavior of the deformation of the brush part of the brush roller restoring to its original state, the toner remaining on the brush roller may be repelled from the brush part and flow out of the cleaning device. The toner that flows out of the cleaning device may then be carried by the air flow and contaminate the inside of the image forming device, which may cause image defects.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to prevent the toner remaining on the brush roller from flowing out of the cleaning device. [Means for solving the problem]

[0010] The above object is achieved by the cleaning device and image forming apparatus according to the present invention. In summary, the present invention comprises a brush roller that contacts an image carrier that carries a toner image and electrically attracts and collects toner on the image carrier as it rotates, and a housing that supports the brush roller and forms a storage section that stores the toner collected from the image carrier, the housing having a scattering prevention section that is provided along the rotation axis direction of the brush roller so as to contact the brush roller, a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller in the rotation direction of the brush roller and upstream of the contact section between the brush roller and the image carrier, and a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller in the rotation direction of the brush roller and upstream of the contact section between the brush roller and the image carrier, and a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller in the rotation direction of the brush roller and upstream of the contact section between the brush roller and the image carrier, and a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller in the rotation direction of the brush roller, and a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller and upstream of the contact section between the brush roller and the image carrier, and a shielding section that is provided along the rotation axis direction of the brush roller downstream of the contact section between the scattering prevention section and the brush roller ... and a receiving portion for receiving detached toner, wherein, in a cross section substantially perpendicular to the direction of the rotation axis of the brush roller, when the position of the scattering prevention portion closest to the rotation center of the brush roller is defined as a first position, the position of the shielding portion closest to the rotation center is defined as a second position, and a tangent to the circumscribing circle of the brush roller that is substantially perpendicular to a line passing through the rotation center and the first position is defined as a scattering prevention portion tangent, the shielding portion is continuously provided at least from the position that intersects with the scattering prevention portion tangent to the second position downstream in the rotation direction of the brush roller, the distance from the rotation center to the second position is greater than the distance from the rotation center to the first position, and the receiving portion is provided below the first position.

[0011] According to another aspect of the present invention, there is provided an image forming apparatus comprising the cleaning device of the present invention and the image carrier. Effect of the Invention

[0012] According to the present invention, it is possible to prevent the toner remaining on the brush roller from flowing out to the outside of the cleaning device. [Brief description of the drawings]

[0013] [Figure 1]FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 2] FIG. 2 is an external perspective view of the cleaning device. [Diagram 3] FIG. [Figure 4] 5 is a schematic cross-sectional view of a cleaning device illustrating a state in which secondary transfer residual toner is collected. FIG. [Diagram 5] 4 is a schematic cross-sectional view of the vicinity of a scattering prevention unit and a shielding unit of the cleaning device. FIG. [Figure 6] 11 is a schematic cross-sectional view of the vicinity of a scattering prevention unit and a shielding unit of a cleaning device according to a reference example. FIG. [Figure 7] FIG. 11 is a schematic cross-sectional view of the vicinity of a scattering prevention unit in a cleaning device of a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The cleaning device and image forming apparatus according to the present invention will be described in more detail below with reference to the drawings.

[0015] [Example 1] 1. Configuration and operation of image forming apparatus 1 is a schematic cross-sectional view of an image forming apparatus 100 of this embodiment. The image forming apparatus 100 of this embodiment is a tandem-type full-color printer employing an intermediate transfer system that is capable of forming a full-color image on a sheet-shaped recording material P using an electrophotographic system. The image forming apparatus 100 forms an image on the recording material P in response to an image signal (image information) transmitted from an external device such as a personal computer.

[0016] The image forming apparatus 100 has four image forming units 1Y, 1M, 1C, and 1K that form images of each color, yellow (Y), magenta (M), cyan (C), and black (K), as a plurality of image forming units. These four image forming units 1Y, 1M, 1C, and 1K are arranged in a row along the moving direction of the image transfer surface arranged substantially horizontally of the intermediate transfer belt 31 described later. Note that elements having the same or corresponding functions or configurations provided for each color may be generally described by omitting the Y, M, C, and K at the end of the reference numerals indicating that they are elements for any one of the colors. In this embodiment, the image forming unit 1 is configured with a photosensitive drum 11, a charger 12, an exposure device 13, a developing device 14, a drum cleaning device 52, and the like described later.

[0017] The photosensitive drum 11, which is a drum-shaped (cylindrical) photosensitive member (electrophotographic photosensitive member) serving as a first image carrier that carries a toner image, is rotated in the direction of arrow R4 (counterclockwise direction) in the figure at a predetermined peripheral speed (process speed). The surface of the rotating photosensitive drum 11 is uniformly charged to a predetermined potential of a predetermined polarity (negative polarity in this embodiment) by a charging device 12 serving as a charging means. The surface of the charged photosensitive drum 11 is scanned and exposed by an exposure device (laser scanner) 13 serving as an exposure means in response to an image signal, and an electrostatic latent image (electrostatic image) is formed on the photosensitive drum 11. The electrostatic latent image formed on the photosensitive drum 11 is developed (visualized) by a developing device 14 serving as a developing means, which supplies toner as a developer, and a toner image (toner image, developer image) is formed on the photosensitive drum 11. In this embodiment, toner charged with the same polarity as the charge polarity of the photosensitive drum 11 (negative polarity in this embodiment) adheres to the exposed portion (image portion) on the photosensitive drum 11, which has been uniformly charged and then exposed to light, thereby decreasing the absolute value of the potential (reverse development method). In this embodiment, the normal charge polarity of the toner, which is the main charge polarity of the toner during development, is negative polarity.

[0018] Opposing the four photosensitive drums 11, an intermediate transfer belt 31, which is an intermediate transfer body formed of an endless belt, is disposed as a second image carrier that carries a toner image. The intermediate transfer belt 31 is stretched around a driving roller 33, a tension roller 34, a secondary transfer pre-roller 35, a secondary transfer inner roller 32, and an opposing roller 36 as a plurality of tension rollers, and is stretched with a predetermined tension. The intermediate transfer belt 31 rotates (moves around) in the direction of arrow R1 (clockwise direction) in the figure at a peripheral speed (process speed) corresponding to the peripheral speed of the photosensitive drum 11, by transmitting a driving force when the driving roller 33 is driven to rotate. On the inner peripheral surface side of the intermediate transfer belt 31, primary transfer rollers 15Y, 15M, 15C, and 15K, which are roller-shaped primary transfer members as primary transfer means, are disposed corresponding to the photosensitive drums 11Y, 11M, 11C, and 11K, respectively. The primary transfer roller 15 is pressed against the photosensitive drum 11 and contacts the photosensitive drum 11 via the intermediate transfer belt 31 to form a primary transfer portion (primary transfer nip) N1, which is a contact portion between the photosensitive drum 11 and the intermediate transfer belt 31. The tension rollers 32, 34, 35, 36 other than the driving roller 33 and each primary transfer roller 15 are rotated following the rotation of the intermediate transfer belt 31. The toner image formed on the photosensitive drum 11 is transferred (primary transfer) onto the rotating intermediate transfer belt 31 as a transfer target at the primary transfer portion N1. During the primary transfer, a predetermined primary transfer bias (primary transfer voltage) of a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the primary transfer roller 15. For example, when a full-color image is formed, the toner images of the colors Y, M, C, and K formed on each photosensitive drum 11 are transferred sequentially so as to be superimposed on the same image position on the intermediate transfer belt 31.

[0019] Meanwhile, recording material P such as paper or plastic sheet stored in feeding cassettes 91, 92, 93 as feeding units is sent out by the rotation of any one of feeding rollers 94, 95, 96 as feeding members. This recording material P is transported through a feeding conveying path 97 to registration rollers 21 as a recording material conveying member. This recording material P is transported by the registration rollers 21 to a secondary transfer unit N2 described later in synchronization with the toner image on the intermediate transfer belt 31.

[0020] On the outer peripheral surface side of the intermediate transfer belt 31, a secondary transfer outer roller 41, which is a roller-shaped secondary transfer member serving as a secondary transfer means, is disposed at a position facing the secondary transfer inner roller 32. The secondary transfer outer roller 41 is pressed toward the secondary transfer inner roller 32 and abuts against the secondary transfer inner roller 32 via the intermediate transfer belt 31 to form a secondary transfer portion (secondary transfer nip) N2, which is a contact portion between the intermediate transfer belt 31 and the secondary transfer outer roller 41. That is, the secondary transfer portion N2 is formed by sandwiching the intermediate transfer belt 31 between the secondary transfer outer roller 41 and the secondary transfer inner roller 32. The secondary transfer outer roller 41 may be rotated by the rotation of the intermediate transfer belt 31 or may be driven to rotate. The toner image formed on the intermediate transfer belt 31 is transferred (secondarily transferred) onto the recording material P, which is a transfer target material being conveyed while being sandwiched between the intermediate transfer belt 31 and the secondary transfer outer roller 41, in the secondary transfer portion N2. During the secondary transfer, a predetermined secondary transfer bias (secondary transfer voltage) having a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the secondary transfer outer roller 41. The secondary transfer inner roller 32 is electrically grounded. Note that a secondary transfer bias having the same polarity as the normal charging polarity of the toner may be applied to the secondary transfer inner roller 32, and the secondary transfer outer roller 41 may be electrically grounded.

[0021] The recording material P onto which the toner image has been transferred is transported by a transport belt 90 serving as a recording material transport member to a fixing device 5 serving as a fixing means. The fixing device 5 applies heat and pressure to the recording material P bearing the unfixed toner image, thereby fixing (melting and bonding) the toner image onto the recording material P. The recording material P onto which the toner image has been fixed passes through a discharge transport path 98 and is discharged (output) onto a discharge tray 99 serving as a discharge section.

[0022] The toner (primary transfer toner) remaining on the photosensitive drum 11 after the primary transfer is removed from the photosensitive drum 11 by a drum cleaning device 52 as a cleaning device and collected. In addition, a first belt cleaning device 50 and a second belt cleaning device 51 as cleaning devices are arranged on the outer peripheral surface side of the intermediate transfer belt 31. Adherents such as toner (secondary transfer residual toner) remaining on the intermediate transfer belt 31 after the secondary transfer are removed from the intermediate transfer belt 31 by the first and second belt cleaning devices 50 and 51 and collected. The first and second belt cleaning devices 50 and 51 are arranged downstream of the secondary transfer portion N2 and upstream of the primary transfer portion N1 (the most upstream primary transfer portion N1Y) in the rotation direction (conveyance direction, surface movement direction) of the intermediate transfer belt 31. Particularly, in this embodiment, the first belt cleaning device 50 is arranged at a position facing the opposing roller 36. That is, in this embodiment, the first belt cleaning device 50 is disposed downstream of the secondary transfer inner roller 32 and upstream of the drive roller 33 in the rotation direction of the intermediate transfer belt 31. Also, in this embodiment, the second belt cleaning device 51 is disposed at a position facing the drive roller 33. That is, in this embodiment, the second belt cleaning device 51 is disposed downstream of the first belt cleaning device 50 and upstream of the primary transfer portion N1 (the most upstream primary transfer portion N1Y) in the rotation direction of the intermediate transfer belt 31.

[0023] 2.Cleaning device Next, the cleaning device will be described in more detail. The image forming apparatus 100 of this embodiment has a drum cleaning device 52, a first belt cleaning device 50, and a second belt cleaning device 51 as cleaning devices. Here, the first belt cleaning device 50 will be described as a representative example. However, the present invention can also be applied to other cleaning devices such as the drum cleaning device 52 and the second belt cleaning device 51. Hereinafter, the first belt cleaning device 50 will also be simply referred to as the "cleaning device 50".

[0024] FIG. 2 is an external perspective view of the cleaning device 50 in this embodiment. FIG. 3 is a cross-sectional view of the vicinity of the cleaning device 50 in this embodiment. FIG. 4 is a schematic cross-sectional view of the vicinity of the cleaning device 50 in this embodiment, showing how toner (secondary transfer residual toner) on the intermediate transfer belt 31 is collected. Note that, with respect to the image forming apparatus 100 and its elements (such as the cleaning device 50), the up-down direction refers to the up-down direction in the direction of gravity (vertical direction), but does not mean just above or just below, and includes the upper side and lower side of a horizontal plane passing through the element or position of interest. In addition, the positional relationship and distance (intrusion amount, gap) of each part of the cleaning device 50 described below are those when viewed from the cross section shown in FIG. 3 and FIG. 4 (a cross section substantially perpendicular to the rotation axis direction of the tension rollers 32 to 36 of the intermediate transfer belt 31 and the brush roller 54 described later).

[0025] As shown in Figures 2 and 3, the cleaning device 50 has a housing (cleaning container) 53, a brush roller 54 as a cleaning member, a metal roller 55 as a collection member, a blade 56 as a scraping member constituting a removal member, and a conveying screw 57 as a conveying member.

[0026] The brush roller 54 is an example of a rotatable conductive elastic roller having a conductive elastic layer on the outer periphery. The brush roller 54 collects toner on the intermediate transfer belt 31. In this embodiment, the brush roller (fur brush roller) 54 has a core metal (core material) 54a and a brush part (fur brush) 54b provided to cover the circumferential surface of the core metal 54a. The brush part 54b is formed of conductive nylon fibers as elastic conductive fibers. The brush roller 54 is rotatably supported by the housing 53. The brush roller 54 is disposed at a position where the brush part 54b penetrates the intermediate transfer belt 31. The rotation axis direction of the brush roller 54 is approximately parallel to the rotation axis direction of the tension rollers 32 to 36 of the intermediate transfer belt 31 (the width direction approximately perpendicular to the moving direction of the surface of the intermediate transfer belt 31). The width of the brush part 54b in the rotation axis direction of the brush roller 54 is equal to the width of the intermediate transfer belt 31. In this embodiment, the brush roller 54 rotates in the direction of the arrow R2 in the figure (clockwise direction). That is, in this embodiment, the brush roller 54 rotates in the same direction as the rotation direction of the tension rollers 32 to 36 of the intermediate transfer belt 31. Also, in this embodiment, the rotation direction R2 of the brush roller 54 is a counter direction to the rotation direction R1 of the intermediate transfer belt 31. That is, at the contact portion between the brush roller 54 and the intermediate transfer belt 31, the movement direction of the brush portion 54b of the brush roller 54 is opposite to the movement direction of the surface of the intermediate transfer belt 31. By setting the rotation direction of the brush roller 54 in this direction, the contact area between the intermediate transfer belt 31 and the brush portion 54b of the brush roller 54 is increased, and the efficiency of collecting toner on the intermediate transfer belt 31 is improved.

[0027] The metal roller 55 is an example of a rotatable conductive recovery member. The metal roller 55 recovers toner from the brush roller 54. In this embodiment, the metal roller 55 is entirely made of conductive metal (such as stainless steel), but the outer circumferential surface may be coated with a material other than metal. The metal roller 55 is rotatably supported by the housing 53. The rotation axis direction of the metal roller 55 is approximately parallel to the rotation axis direction of the brush roller 54 (the rotation axis direction of the tension rollers 32 to 36 of the intermediate transfer belt 31). The width of the roller portion (the portion that can contact the brush portion 54b of the brush roller 54) in the rotation axis direction of the metal roller 55 is equal to the width of the brush portion 54b of the brush roller 54. The brush roller 54 is disposed at a position where the brush portion 54b enters the metal roller 55. In this embodiment, the metal roller 55 rotates in the direction of the arrow R3 in the figure (counterclockwise direction). That is, in this embodiment, metal roller 55 rotates in the opposite direction to the rotation direction of brush roller 54 (stretching rollers 32 to 36 of intermediate transfer belt 31). Also, in this embodiment, rotation direction R3 of metal roller 55 is with respect to rotation direction R2 of brush roller 54. That is, at the contact portion between metal roller 55 and brush roller 54, the movement direction of the surface of metal roller 55 is the same as the movement direction of brush portion 54b of brush roller 54.

[0028] The blade 56 is made of a plate-like member made of a flexible rubber material or the like. The blade 56 physically scrapes off and removes the toner from the metal roller 55. In this embodiment, the blade 56 is made of a substantially rectangular flat plate in plan view, having a predetermined length in the longitudinal direction arranged substantially parallel to the rotation axis direction of the metal roller 55 and in the lateral direction substantially perpendicular to the longitudinal direction, and having a predetermined thickness. The width of the blade 56 in the longitudinal direction is equal to the width of the roller portion (the portion that can contact the brush portion 54b of the brush roller 54) in the rotation axis direction of the metal roller 55. The blade 56 is supported by the housing 53 at one end (fixed end) in the lateral direction. The blade 56 may be supported by the housing 53 via a support member. The edge portion at the tip of the other end (free end) in the lateral direction of the blade 56 is in contact with the surface of the metal roller 55. The contact direction of the blade 56 with the metal roller 55 is counter to the rotation direction of the metal roller 55. That is, the blade 56 is in contact with the surface of the metal roller 55 with its free end facing upstream in the direction of movement of the surface of the metal roller 55. The blade 56 is also disposed at a position where it is pressed against the metal roller 55.

[0029] The conveying screw 57 is rotatably supported by the housing 53. The rotation axis direction of the conveying screw 57 is approximately parallel to the rotation axis direction of the brush roller 54 (the rotation axis direction of the tension rollers 32 to 36 of the intermediate transfer belt 31). The conveying screw 57 is disposed close to the bottom of a storage section 61 formed by the housing 53 for storing the toner scraped off from the metal roller 55 by the blade 56.

[0030] In this embodiment, the intermediate transfer belt unit 30 includes the intermediate transfer belt 31, tension rollers 32 to 36 for the intermediate transfer belt 31, primary transfer rollers 35, and a frame (not shown) supporting these rollers. The cleaning device 50 is detachable from the intermediate transfer belt unit 30.

[0031] On the other hand, the counter roller 36 is disposed on the inner peripheral surface side of the intermediate transfer belt 31 so as to be adjacent to the brush roller 54 and in contact with the inner peripheral surface of the intermediate transfer belt 31. The intermediate transfer belt 31 is sandwiched between the counter roller 36 and the brush roller 54. A power supply unit (not shown) is connected to the counter roller 36. A cleaning power source (high voltage board) 37 (FIG. 4) provided in the image forming apparatus 100 is connected to the power supply unit as an application unit that applies a predetermined cleaning bias (cleaning voltage) to the counter roller 36. That is, the counter roller 36 is connected to the cleaning power source 37 via the power supply unit. Also, an electrode (not shown) connected to GND is connected to the metal roller 55. That is, the metal roller 55 is electrically grounded via the electrode (FIG. 4). The brush roller 54 is electrically floated. A cleaning bias is applied from the cleaning power source 37 to the counter roller 36, so that a bias is applied (current is supplied) to the metal roller 55 via the intermediate transfer belt 31 and the brush roller 54.

[0032] In this embodiment, the toner on the intermediate transfer belt 31 after the secondary transfer is mainly charged with negative polarity (normal charging polarity), and a cleaning bias of negative polarity is applied to the opposing roller 36. For example, in this embodiment, a cleaning bias of -1 kV is applied to the opposing roller 36. However, the polarity of the toner and the value of the cleaning bias are not limited to this. For example, if the polarity of the toner that reaches the cleaning device 50 is mainly positive polarity, a cleaning bias of positive polarity may be applied to the opposing roller 36. The cleaning bias may be constant current controlled or constant voltage controlled. The constant current control is a control that adjusts the output of the power source so that the current supplied to the supply target is approximately constant at a target current. The constant voltage control is a control that adjusts the output of the power source so that the voltage applied to the application target is approximately constant at a target voltage. When the cleaning bias is applied to the opposing roller 36, the potential of the opposing roller 36 becomes approximately the same potential as the value of the cleaning bias. The potential of the brush roller 54 becomes a potential with the same polarity as the potential of the opposing roller 36 and with an absolute value smaller than that of the potential of the opposing roller 36. Moreover, since the metal roller 56 is electrically grounded, the potential of the metal roller 56 is approximately 0 V. As a result, a potential difference is formed between the opposing roller 36 and the brush roller 54, such that the opposing roller 36 has a higher potential on the negative polarity side (the same polarity side as the normal charging polarity of the toner) than the brush roller 54. Also, a potential difference is formed between the brush roller 54 and the metal roller 55, such that the brush roller 54 has a higher potential on the negative polarity side (the same polarity side as the normal charging polarity of the toner) than the metal roller 55.

[0033] The cleaning device 50 has a connecting member 60 such as a coupling provided on the housing 53 at one end side in the rotation axis direction of the brush roller 54. The connecting member 60 is connected to, for example, a drive source (not shown) for driving the intermediate transfer belt 31 provided in the image forming apparatus 100. A transmission member such as a gear is provided at one end of the brush roller 54, the metal roller 55, and the conveying screw 57 in the rotation axis direction, and these are connected in sequence via the connecting member 60, and a driving force is transmitted to each of them at a predetermined reduction ratio. In this embodiment, the rotation direction R2 of the brush roller 54 is a counter direction to the rotation direction R1 of the intermediate transfer belt 31, and the rotation direction R3 of the metal roller 55 is a with direction to the rotation direction R2 of the brush roller 54, but is not limited to these rotation directions.

[0034] As shown in FIG. 4, the toner T on the intermediate transfer belt 31 is attracted to the brush portion 54b of the brush roller 54 by the potential difference between the opposing roller 36 and the brush roller 54 formed by the application of the cleaning bias, and is collected. The toner T collected by the brush portion 54b of the brush roller 54 is attracted to the metal roller 55 by the potential difference between the brush roller 54 and the metal roller 55 formed by the application of the cleaning bias, and moves away from the brush roller 54 to the metal roller 55. The toner T that has moved to the metal roller 55 is scraped off by the blade 56 and temporarily stored in a storage section 61 formed inside the housing 53. The toner T stored in the storage section 61 is transported by a transport screw 57 disposed close to the bottom of the storage section 61, and discharged to the outside of the cleaning device 50. The toner T discharged to the outside of the cleaning device 50 passes through a transport path provided in the image forming apparatus 100, and is collected in a collected toner container (not shown) provided in the image forming apparatus 100.

[0035] As shown in FIG. 3 and FIG. 4, the housing 53 of the cleaning device 50 is provided with a scattering prevention part 58 that contacts the brush part 54b of the brush roller 54 downstream of the contact part between the brush roller 54 and the metal roller 55 in the rotation direction of the brush roller 54 and upstream of the contact part between the brush roller 54 and the intermediate transfer belt 31. In this embodiment, the scattering prevention part 58 is formed of a plate-shaped wall part that is continuous over almost the entire area of ​​the brush part 54b along the rotation axis direction of the brush roller 54. The tip part of the scattering prevention part 58 on the brush roller 54 side contacts the brush part 54b of the brush roller 54, and the base part opposite to the tip part extends continuously to the bottom of the storage part 61 and the bottom of the receiving part 62 described later. In this embodiment, the scattering prevention part 58 is provided so as to intrude into the brush part 54b of the brush roller 54. In this embodiment, the intrusion amount W1 (FIG. 4) of the scattering prevention part 58 into the brush part 54b of the brush roller 54 is 1 mm. This intrusion amount W1 is expressed as the difference between the radius of the circumscribing circle of the brush roller 54 and the distance from the rotation center X of the brush roller 54 to the position of the scattering prevention part 58 closest to the rotation center X of the brush roller 54 (the first position P1 described later).

[0036] 3 and 4, the housing 53 of the cleaning device 50 is provided with a shielding portion 59 downstream of the contact portion between the scatter prevention portion 58 and the brush roller 54 in the rotation direction of the brush roller 54 and upstream of the contact portion between the brush roller 54 and the intermediate transfer belt 31. Here, in the cross section shown in FIG. 3 (cross section substantially perpendicular to the rotation axis direction of the brush roller 54), the position of the scatter prevention portion 58 closest to the rotation center X of the brush roller 54 is defined as a first position P1, the position of the shielding portion 59 closest to the rotation center X of the brush roller 54 is defined as a second position P2, and the tangent to the circumscribed circle of the brush roller 54 (the circumference of the brush roller when the brush portion is not deformed) substantially perpendicular to the straight line L2 passing through the rotation center X of the brush roller 54 and the first position P1 of the scatter prevention portion 58 is defined as a scatter prevention portion tangent L1. At this time, the shielding portion 59 is provided continuously from at least the third position P3 intersecting with the scattering prevention portion tangent line L1 to the second position P2 on the downstream side in the rotation direction of the brush roller 54. In this embodiment, the shielding portion 59 is configured as a plate-shaped wall portion that is continuous over almost the entire area of ​​the brush portion 54b along the rotation axis direction of the brush roller 54. The tip portion of the shielding portion 54 on the brush roller 54 side faces or contacts the brush portion 54b of the brush roller 54, and the base end portion on the opposite side to the tip portion extends continuously below the third position P3 to the bottom of the receiving portion 62 described later. The shielding portion 59 is provided so that the distance from the rotation center X of the brush roller 54 to the second position P2 of the shielding portion 59 is greater than the distance from the rotation center X of the brush roller 54 to the first position P1 of the scattering prevention portion 58. Particularly in this embodiment, the shielding portion 59 is provided in a non-contact manner with the brush portion 54b of the brush roller 54. In this embodiment, the gap W2 (FIG. 4) between the second position P2 of the shielding portion 59 and the brush portion 54b of the brush roller 54 is 0.5 mm.

[0037] The penetration amount W1 of the scattering prevention portion 38 into the brush portion 54b of the brush roller 54 is not limited to the value in this embodiment. Typically, this penetration amount W1 is smaller than the penetration amount W3 of the metal roller 55 into the brush portion 54b of the brush roller 54. From the viewpoint of effectively shielding the storage portion 61 from the outside of the cleaning device 50, the penetration amount W1 is typically set to 0.5 mm or more and 3 mm or less, and preferably 1 mm or more and 2 mm or less.

[0038] Moreover, the gap W2 between the shielding portion 59 and the brush portion 54b of the brush roller 54 is not limited to the value of this embodiment. From the viewpoint of further enhancing the effect of suppressing the outflow of the toner T described later, the gap W2 is typically set to 2 mm or less, preferably 1 mm or less, and more preferably 0.5 mm or less. Moreover, the shielding portion 59 may be in contact with the brush portion 54b of the brush roller 54, or may intrude into the brush portion 54b of the brush roller 54. However, in order to obtain the effect of suppressing the outflow of the toner T described later, as described above, it is necessary that the distance from the second position P2 of the shielding portion 59 to the rotation center X of the brush roller 54 is greater than the distance from the first position P1 of the scattering prevention portion 58 to the rotation center X of the brush roller 54. The intrusion amount of the shielding portion 59 into the brush portion 54b of the brush roller 54 is typically set to 1.0 mm or less, and preferably 0.5 mm or less. This intrusion amount is represented by the difference between the radius of the circumscribing circle of the brush roller 54 and the distance from the rotation center X of the brush roller 54 to the second position P2 of the shielding portion 59.

[0039] Here, the above-mentioned penetration amount and gap with respect to the brush portion 54b of the brush roller 54 are represented by values ​​when the cleaning device 50 (brush roller 54) is new (at the start of use).

[0040] 3 and 4, the housing 53 of the cleaning device 50 is provided with a receiving section 62 below the first position P1 of the scattering prevention section 58, which receives the toner T that has been repelled from the brush section 54b of the brush roller 54 by the scattering prevention section 58, as described below. In this embodiment, the receiving section 62 is formed in an area sandwiched between the scattering prevention section 58 and the shielding section 59, which are wall sections that are provided substantially parallel to each other and face each other. In this embodiment, the bottom of the receiving section 62 is formed by the housing 53 and is closed. In addition, the opening between the scattering prevention section 58 and the shielding section 59 at the end of the receiving section 62 on the brush roller 54 side is almost closed by the brush section 54 of the brush roller 54. As a result, in this embodiment, the inside of the receiving section 62 is almost closed from the outside of the cleaning device 50. Note that an opening may be provided in the wall section constituting the scattering prevention section 58 between the bottom of the receiving section 62 and the brush roller 54, and the inside of the receiving section 62 and the inside of the storage section 61 may be communicated with each other. In this case, at least a portion of the toner T received in the receiving section 62 may move to the storage section 61 due to the action of gravity or the like, and may be transported to the outside of the cleaning device 50 by the conveying screw 57 together with the toner T contained inside the storage section 61.

[0041] The scattering prevention section 58 comes into contact with the brush roller 54, thereby blocking the boundary between the outside of the cleaning device 50 and the inside of the cleaning device 50 with the brush roller 54 and the scattering prevention section 58 provided in the housing 53. This makes it possible to prevent, for example, the toner T being transported by the transport screw 57 from flying up (scattering) due to the air flow inside the cleaning device 50 and flowing out of the cleaning device 50.

[0042] On the other hand, when the toner T on the intermediate transfer belt 31 is collected by the brush roller 54, or when the toner T is moved from the brush roller 54 to the metal roller 55, the charge of the negatively charged toner T may become close to zero or the polarity may be reversed by application of a cleaning bias. Such toner T may remain on the brush roller 54 without moving to the metal roller 55. The toner T remaining on the brush roller 54 has a weak electrical binding force and is in a state in which it is easy to separate from the brush roller 54. When the scattering prevention part 58 enters the brush roller 54 in this state, the following occurs. That is, the brush part 54b formed of the fibers of the brush roller 54 is temporarily deformed according to the amount of entry W1 of the scattering prevention part 58 into the brush part 54b. In addition, when the brush part 54b leaves the contact area with the scattering prevention part 58 as the brush roller 54 rotates, the deformed brush part 54b exhibits a behavior of elastically restoring due to an elastic restoring force. In addition, the faster the rotation speed of the brush roller 54 is, and the larger the penetration amount W1 of the scattering prevention portion 58 into the brush portion 54b of the brush roller 54 is, the larger the restoration energy of the brush portion 54b becomes. Due to the behavior of the brush portion 54b of the brush roller 54 restoring its deformation, the toner T remaining on the brush roller 54 is ejected from the brush portion 54b and discharged to the outside of the scattering prevention portion 58.

[0043] 7 is a schematic cross-sectional view of the vicinity of scattering prevention unit 158 ​​in a conventional cleaning device. As shown in FIG. 7(a), in the conventional cleaning device, the downstream side of scattering prevention unit 158 ​​in the rotation direction of brush roller 154 is outside the cleaning device. Therefore, as shown in FIG. 7(b), toner T ejected from brush roller 154 may flow out of the cleaning device. The toner T that has flowed out of the cleaning device may scatter into the transport path of recording material P, for example, and may cause image defects.

[0044] In contrast, FIG. 5 is a schematic cross-sectional view of the vicinity of the scattering prevention unit 58 and the shielding unit 59 in the cleaning device 50 of this embodiment. As shown in FIG. 5, in this embodiment, the shielding unit 59 is provided in the housing 53. The shielding unit 59 blocks the toner T that is thrown out from the brush part 54b due to contact between the brush roller 54 and the scattering prevention unit 58, and prevents the toner T from flowing out to the outside of the cleaning device 50. As described above, the shielding unit 59 is provided continuously from at least the third position P3 that intersects with the scattering prevention unit tangent line L1 to the second position P2 that is closest to the rotation center X of the brush roller 54 (FIG. 3). This allows the shielding unit 59 to effectively block the toner T that is thrown out from the brush part 54b of the brush roller 54 and moves in the direction along the scattering prevention unit tangent line L1.

[0045] 3 (a cross section substantially perpendicular to the rotation axis direction of the brush roller 54), a straight line passing through the rotation center X of the brush roller 54 and the center of the contact portion between the brush roller 54 and the intermediate transfer belt 31 in the moving direction of the surface of the intermediate transfer belt 31 is defined as a straight line L3. In this embodiment, the second position P2 of the shielding portion 59, which is closest to the rotation center X of the brush roller 54, is disposed closer to the intermediate transfer belt 31 than the first position P1 of the scattering prevention portion 58, which is closest to the rotation center X of the brush roller 54. This enhances the effect of blocking the toner T ejected from the brush portion 54b of the brush roller 54 by the shielding portion 59. The toner T blocked by the shielding portion 59 is received by the receiving portion 62, and typically falls by the action of gravity and accumulates at the bottom of the receiving portion 62.

[0046] Here, by making the shielding portion 59 non-contact with the brush roller 54, the brush portion 54b of the brush roller 54 does not deform even when the brush portion 54b of the brush roller 54 passes near the shielding portion 59. Therefore, the toner T is not repelled from the brush portion 54b, and the effect of suppressing the toner T from flowing out to the outside of the cleaning device 50 is enhanced. However, as described above, the shielding portion 59 and the brush roller 54 may be configured to be in contact with each other. Even in this case, by arranging the second position P2 of the shielding portion 59 at a position farther from the rotation center X of the brush roller 54 than the first position P1 of the scattering prevention portion 58 as described above, a certain effect of suppressing the toner T from flowing out to the outside of the cleaning device 50 can be obtained.

[0047] In this embodiment, the opening of the cleaning device 50 is disposed at the top, and the receiving portion 62 is provided below the first position P1, which is the closest to the rotation center X of the brush roller 54 of the scattering prevention portion 58. In contrast, a configuration in which the opening of the cleaning device 50 is disposed on the side or below is considered. FIG. 6 is a schematic cross-sectional view of the vicinity of the scattering prevention portion 58 and the shielding portion 59 in a reference example in which the opening of the cleaning device 50 is disposed at the bottom, as an example of a configuration in which the opening of the cleaning device 50 is disposed on the side or below. In this configuration, as in this embodiment, the scattering prevention portion 58 can prevent the toner T scattered inside the cleaning device 50 from flowing out to the outside of the cleaning device 50. In this configuration, the toner T that is repelled from the brush portion 54b at the contact portion between the scattering prevention portion 58 and the brush roller 54 may be blocked by the shielding portion 59 and then reattached to the brush portion 54b. This can prevent the toner T, which has been ejected from the brush portion 54b of the brush roller 54, from flowing out of the cleaning device 50 to some extent. However, in this configuration, the area for receiving the toner T blocked by the shielding portion 59 (the receiving portion 62 in this embodiment) is not provided below the first position P1 of the scattering prevention portion 58 that is closest to the rotation center X of the brush roller 54. In this configuration, the toner T, which has re-adhered to the brush portion 54b, may flow out of the cleaning portion 50 by passing through a gap between the brush portion 54b and the shielding portion 59. In addition, when the shielding portion 59 is brought into contact with the brush portion 54b, the toner T, which has re-adhered to the brush portion 54b, may be ejected from the brush portion 54b. Therefore, in this configuration, a high effect of preventing the toner T from flowing out of the cleaning device 50 as in this embodiment cannot be expected. This is also true for a configuration in which the opening of the cleaning device 50 is provided on the side.

[0048] As described above, in order to suppress the outflow of the toner T from the cleaning device 50, the positional relationship of the shielding portion 59 with respect to the brush roller 54 is important. For example, if the gap between the brush roller 54 and the shielding portion 59 is too large, the toner T may flow out of the cleaning device 50 due to airflow. Also, for example, if the intrusion amount of the shielding portion 59 with respect to the brush roller 54 is too large, the restoration behavior of the brush portion 54b deformed by the shielding portion 59 becomes large, and the toner T may be repelled from the brush portion 54b and flow out of the cleaning device 50. Therefore, in the housing 53, it is preferable that at least the support portion 63 (FIG. 2) of the brush roller 54 and the shielding portion 59 are integrally formed (provided in the same part).

[0049] Thus, in this embodiment, the cleaning device 50 has a brush roller 54 that comes into contact with the image carrier (intermediate transfer belt) 31 that carries a toner image, and electrically attracts and collects the toner T on the image carrier as it rotates, and a housing 53 that supports the brush roller 54 and forms a storage section 61 that stores the toner T collected from the image carrier 31. The housing 53 has a scattering prevention section 58 provided along the rotation axis direction of the brush roller 54 so as to come into contact with the brush roller 54, a shielding section 59 provided along the rotation axis direction of the brush roller 54 downstream of the contact portion between the scattering prevention section 58 and the brush roller 54 in the rotation direction of the brush roller 54 and upstream of the contact portion between the brush roller 54 and the image carrier 31, and a shielding section 59 provided along the rotation axis direction of the brush roller 54 when the brush roller 54 passes through the contact portion between the scattering prevention section 58 and the brush roller 54. and a receiving portion 62 that receives the toner detached from the brush roller 54 by shielding the toner from the brush roller 54. In a cross section substantially perpendicular to the rotation axis direction of the brush roller 54, when a position of the scattering prevention portion 58 closest to the rotation center X of the brush roller 54 is defined as a first position P1, a position of the shielding portion 59 closest to the rotation center X is defined as a second position P2, and a tangent to a circumscribing circle of the brush roller 54 that is substantially perpendicular to a straight line L2 passing through the rotation center X and the first position P1 is defined as a scattering prevention portion tangent L1, the shielding portion 59 is provided continuously at least from a position P3 that intersects with the scattering prevention portion tangent L1 to the second position P2 on the downstream side in the rotation direction of the brush roller 54, the distance from the rotation center X to the second position P2 is greater than the distance from the rotation center X to the first position P1, and the receiving portion 62 is provided below the first position P1.

[0050] In this embodiment, the scattering prevention portion 58 is provided so as to penetrate into the brush roller 54. In addition, in this embodiment, the shielding portion 59 is provided so as not to contact the brush roller 54. In addition, in this embodiment, when viewed in a cross section substantially perpendicular to the rotation axis direction of the brush roller 54, the second position P2 is disposed closer to the image carrier 31 than the first position P1 in a direction along a straight line L3 passing through the rotation center X and the center of the contact portion between the brush roller 54 and the image carrier 31 in the moving direction of the surface of the image carrier 31. In addition, in this embodiment, the brush roller 54 rotates so that the moving direction of the brush roller 54 and the moving direction of the image carrier 31 are opposite to each other at the contact portion between the brush roller 54 and the image carrier 31. In addition, in this embodiment, the support portion 63 that supports the brush roller 54 and the shielding portion 59 are provided in the same part in the housing 53. In this embodiment, the cleaning device 50 has a recovery member (metal roller) 55 that contacts the brush roller 54 downstream of the contact portion between the brush roller 54 and the image carrier 31 in the rotation direction of the brush roller 54 and upstream of the contact portion between the scattering prevention portion 58 and the brush roller 54 to recover toner from the brush roller 54, and the toner recovered from the brush roller 54 by the recovery member 55 is stored in the storage portion 62. In this embodiment, the cleaning device 50 has a removal member (blade) 56 that contacts the rotatable recovery member 55 to remove toner from the recovery member 55, and the toner removed from the recovery member 55 by the removal member 56 is stored in the storage portion 62. In this embodiment, the cleaning device 50 has a transport member (transport screw) 57 that transports the toner stored in the storage portion 62 to the outside of the cleaning device 50. In this embodiment, an image forming apparatus 100 is provided that has the cleaning device 50 and the image carrier 31. Moreover, the cleaning device 50 may be detachable from the image carrier 31. Moreover, in this embodiment, the image carrier 31 is an intermediate transfer body that carries and transports a toner image transferred from another image carrier 11 to a recording material P for transfer thereto.

[0051] As described above, according to this embodiment, the toner T remaining on the brush roller 54 and thrown out due to the deformation and restoration behavior of the brush portion 54b by the scattering prevention portion 58 can be blocked by the shielding portion 59 and received in the receiving portion 62. This makes it possible to prevent the toner T thrown out from the brush portion 54b of the brush roller 54 from flowing out to the outside of the cleaning device 50. Therefore, it is possible to prevent the toner T flowing out of the cleaning device 50 from contaminating the inside of the image forming apparatus 100 and causing image defects.

[0052] [others] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments.

[0053] In the above embodiment, the cleaning device 50 is configured to move the toner T collected by the brush roller 54 to the metal roller 55 and scrape the toner T off the metal roller 55 with the blade 56, but is not limited to this. For example, the cleaning device 50 may be configured not to include the metal roller 55, but to include a scraping member that functions as a collection member that comes into contact with the brush roller 54, and to separate the toner T from the brush roller 54 with this scraping member.

[0054] In the above embodiment, a cleaning bias (a bias having the same polarity as the main charge polarity of the toner to be collected) is applied to the opposing roller 36 to electrically ground the metal roller 55, but the present invention is not limited to this. For example, a cleaning bias (a bias having the opposite polarity to the main charge polarity of the toner to be collected) may be applied to the metal roller 55 to electrically ground the opposing roller 36. In this case, the same potential difference as in the above embodiment can be formed between the opposing roller 36 and the brush roller 54, and between the brush roller 54 and the metal roller 55. In addition, for example, a cleaning bias (a bias having the opposite polarity to the main charge polarity of the toner to be collected) may be applied to the brush roller 54 and the metal roller 55, respectively, to electrically ground the opposing roller 36. In this case, the absolute value of the cleaning bias applied to the metal roller 55 is made larger than the absolute value of the cleaning bias applied to the brush roller 54. This allows the same potential difference as in the above embodiment to be formed between the opposing roller 36 and the brush roller 54, and between the brush roller 54 and the metal roller 55.

[0055] In the above embodiment, the cleaning device 50 is provided with the conveying screw 57, and the conveying screw 57 is used to discharge the toner T to the outside of the cleaning device 50, but the present invention is not limited to this. For example, the cleaning device 50 may be configured to retain the collected toner T inside, and to replace the image carrier and the cleaning device 50 together, or to replace the cleaning device 50 substantially alone, at a predetermined timing (e.g., periodically). Also, for example, the inside of the cleaning device 50 may be cleaned at a predetermined timing (e.g., periodically) to remove the toner T collected by the cleaning device 50 from the cleaning device 50.

[0056] In the above embodiment, the material of the fibers constituting the brush portion 54b of the brush roller 54 is conductive nylon, but the material is not limited to this and may be any fiber having conductivity. The brush roller may have the following configuration, for example. Conductive brush fibers (raw yarn) are woven into a conductive base cloth that is entirely conductive or a conductive base cloth whose back surface is coated with a conductive agent to form the brush portion. The base cloth into which the conductive brush fibers of the brush portion are woven is wound around a core metal. Then, the brush portion and the core metal are bonded (for example, bonded with a conductive adhesive) so as to be electrically conductive. The core metal can be formed of a rod or pipe made of a conductive metal. Examples of the material of the conductive brush fibers constituting the brush portion include polyamide (such as nylon) with conductive carbon dispersed therein, polyester, acrylic, rayon, and the like.

[0057] In the above embodiment, the brush roller is configured to have raised naps formed by weaving brush fibers into a base fabric, but the present invention is not limited to this. The brush roller may be configured to have a brush portion formed of a nonwoven fabric made of conductive fiber filaments on a core metal. For example, when the image carrier has an elastic layer such as a rubber layer on the surface, or when a long life of the image carrier is required, it is preferable that the elastic roller of the cleaning device has a brush portion formed of fibers as the elastic layer. This is from the viewpoint of obtaining good cleaning performance while reducing wear of the image carrier, which is the object to be cleaned. However, depending on the configuration of the image carrier, which is the object to be cleaned, the elastic roller may have an elastic layer formed of sponge rubber (foamed elastic body), etc.

[0058] In the above embodiment, the image forming apparatus 100 has two cleaning devices 50 and 51 as a plurality of cleaning devices that collect the toner T on the intermediate transfer belt 31, but is not limited to such a configuration. For example, the image forming apparatus 100 may have only one cleaning device that collects the toner T on the intermediate transfer belt 31, or may have three or more. Also, a configuration may be adopted in which a plurality of brush rollers are provided inside the frame (cleaning container) of one cleaning device, and each brush roller collects the toner T on the intermediate transfer belt 31. When the cleaning apparatus has a plurality of brush rollers, the scattering prevention unit and the shielding unit may be provided for each brush roller, or may be provided for at least one brush roller (for example, the brush roller located most downstream in the moving direction of the surface of the object to be cleaned).

[0059] In the above embodiment, the present invention is applied to the first belt cleaning device 50, but the present invention may be applied to other cleaning devices such as the drum cleaning device 52 and the second belt cleaning device 51. Any of the cleaning devices may have the same configuration, and the direction and timing of the cleaning bias to be applied may be appropriately set for each device. In this way, the present invention is not limited to a cleaning device that collects toner on an intermediate transfer belt, but can also be applied to other cleaning devices such as a cleaning device that collects toner on a photosensitive drum. In other words, the present invention can be applied to any cleaning device that collects toner on an image carrier (photosensitive body, intermediate transfer body, etc.) that carries a toner image.

[0060] In the above embodiment, the cleaning device that collects the toner on the intermediate transfer belt and the cleaning device that collects the toner on the photosensitive drum are of the electrostatic cleaning type, but the present invention is not limited to this. As long as any one of the cleaning devices provided in the image forming apparatus is of the electrostatic cleaning type, the present invention can be applied to that cleaning device.

[0061] In the above embodiment, the cleaning device has been described as a cleaning device for an image forming apparatus that forms a full-color image, but the present invention is not limited to this configuration and can be understood as a cleaning device for an image forming apparatus that forms a monochrome image, for example.

[0062] Furthermore, the cleaning device does not need to be detachable from the image carrier, and may be provided in a cartridge integrated with the image carrier. [Explanation of symbols]

[0063] 31 Intermediate transfer belt (image carrier) 36 Counter Roller 50 Belt cleaning device (cleaning device) 53 Case 54 Brush roller 55 Metal roller (recovery material) 56 Blade (scraping member) 57 Conveying screw (conveying member) 58 Scattering prevention part 59 Shield part 61 Storage unit 62 Receptor 100 Image forming device

Claims

1. A brush roller that contacts an image carrier that holds a toner image and rotates to electrically attract and collect the toner on the image carrier, It has a housing that supports the brush roller and forms a storage section for storing toner recovered from the image carrier, The housing includes: a splash prevention section provided along the rotation axis direction of the brush roller so as to contact the brush roller; a shielding section provided along the rotation axis direction of the brush roller downstream of the contact point between the splash prevention section and the brush roller and upstream of the contact point between the brush roller and the image carrier in the rotation direction of the brush roller; and a receiving section for receiving toner that has detached from the brush roller as the brush roller passes the contact point between the splash prevention section and the brush roller. In a cross-section substantially perpendicular to the rotation axis direction of the brush roller, when the position of the scattering prevention part closest to the rotation center of the brush roller is defined as the first position, the position of the shielding part closest to the rotation center is defined as the second position, and the tangent line of the circumscribed circle of the brush roller, which is substantially perpendicular to the line passing through the rotation center and the first position, is defined as the tangent line of the scattering prevention part, The shielding portion is provided continuously from at least a position intersecting the tangent to the scattering prevention portion to the second position downstream in the rotational direction of the brush roller. The distance from the center of rotation to the second position is greater than the distance from the center of rotation to the first position. The cleaning device is characterized in that the receiving portion is provided below the first position.

2. The cleaning device according to claim 1, characterized in that the splash prevention part is provided so as to enter the brush roller.

3. The cleaning device according to claim 1, characterized in that the shielding portion is provided in a non-contact manner with respect to the brush roller.

4. The cleaning apparatus according to claim 1, characterized in that, when viewed in a cross-section substantially perpendicular to the rotation axis direction of the brush roller, the second position is located closer to the image carrier than the first position in a direction along a straight line passing through the rotation center and the center of the contact portion between the brush roller and the image carrier in the direction of movement of the surface of the image carrier.

5. The cleaning device according to claim 1, characterized in that the brush roller rotates such that the direction of movement of the brush roller and the direction of movement of the image carrier are opposite at the contact portion between the brush roller and the image carrier.

6. The cleaning device according to claim 1, characterized in that, in the housing, the support portion for supporting the brush roller and the shielding portion are provided on the same part.

7. The cleaning device according to claim 1, further comprising a recovery member that contacts the brush roller downstream of the contact portion between the brush roller and the image carrier and upstream of the contact portion between the splash prevention portion and the brush roller in the rotational direction of the brush roller to recover toner from the brush roller, wherein the toner recovered from the brush roller by the recovery member is stored in the storage portion.

8. The cleaning device according to claim 7, wherein the recovery member is rotatable and has a removal member that contacts the recovery member to remove toner from the recovery member, and the toner removed from the recovery member by the removal member is stored in the storage section.

9. The cleaning device according to claim 1, further comprising a transport member for transporting the toner stored in the storage section toward the outside of the cleaning device.

10. An image forming apparatus comprising a cleaning device according to any one of claims 1 to 9, and the image carrier.

11. The image forming apparatus according to claim 10, characterized in that the cleaning device is detachable from the image carrier.

12. The image forming apparatus according to claim 10, characterized in that the image carrier is an intermediate transfer body that carries and transports a toner image transferred from another image carrier to a recording material.

Images