Image forming device

Abstract

To prevent dirt on a non-transfer surface of a recording medium.SOLUTION: An image forming apparatus comprises: a rotating body that has a concave part formed in its outer peripheral surface; a transfer unit that is in contact with the outer peripheral surface of the rotating body and transfers toner to a recording medium passing through between the rotating body and the transfer unit; and a brush that is in contact with the outer peripheral surface of the rotating body and removes the toner adhered to the outer peripheral surface.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Patent document 1 discloses a transfer device that transfers an image on an image carrier, characterized in that it has a transfer material transport means that moves the transfer material endlessly along a circular movement path, a gripper piece attached to this transport means, supported on a rotating shaft and rotating relative to a base member, that grips the leading edge of the transfer material, and a switch member attached to the base member, and that detects the presence of the transfer material in the gripper by cutting out a portion of the gripper piece at the position of the switch member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 58-005769 Summary of the Invention [Problem to be solved by the invention]

[0004] One possible image forming apparatus includes a rotating body having a recess formed on its outer peripheral surface and a transfer unit that contacts the outer peripheral surface of the rotating body and transfers toner to a recording medium passing between the rotating body and the blade. In this configuration, when a blade is pressed against the outer peripheral surface of the rotating body to remove toner adhering to the outer peripheral surface, the blade may collide with an edge of the recess formed on the outer peripheral surface of the rotating body, causing vibration of the rotating body and the blade. When vibration occurs in the rotating body and the blade, toner adhering to the rotating body and the blade may fly up and adhere to the non-transfer surface of the recording medium passing between the transfer unit and the rotating body, causing the non-transfer surface to become dirty.

[0005] The present invention aims to prevent contamination of the non-transfer surface of the recording medium compared to a configuration in which a blade is pressed against the outer peripheral surface of a rotating body to remove toner adhering to the outer peripheral surface. [Means for solving the problem]

[0006] The first aspect comprises a rotating body having a recess formed on its outer peripheral surface, a transfer unit that contacts the outer peripheral surface of the rotating body and transfers toner to a recording medium passing between the rotating body and the transfer unit, and a brush that contacts the outer peripheral surface of the rotating body and removes toner adhering to the outer peripheral surface.

[0007] In a second mode, the brush rotates in a forward direction relative to the rotation direction of the rotating body.

[0008] In a third aspect, the peripheral speed ratio of the brush to the rotating body exceeds one.

[0009] In a fourth aspect, when the outer peripheral surface of the rotating body is divided equally into a downstream portion and an upstream portion in the rotation direction of the rotating body based on the contact position of the transfer part with the outer peripheral surface of the rotating body, the brush contacts the downstream portion.

[0010] In a fifth aspect, the brush rotates and includes a contact member that comes into contact with the rotating brush to cause toner adhering to the brush to fall off.

[0011] In a sixth aspect, when the amount of bite of the brush into the contact member is KA and the amount of bite of the brush into the rotating body is KB, the relationship KA>KB holds.

[0012] In the seventh aspect, when the brush is equally divided into a downstream portion and an upstream portion in the rotation direction based on the contact position of the brush with respect to the outer peripheral surface of the rotating body, the contact member contacts the downstream portion.

[0013] In an eighth aspect, the contact position of the transfer portion with the outer circumferential surface of the rotating body is disposed above the brush, and the contact member is disposed below the brush.

[0014] A ninth aspect includes a housing that is detachably attached to the main body of the image forming device, that houses the brush inside, and that has an opening that exposes the contact portion of the brush with the rotating body, and the brush is detachably attached to the housing when removed from the main body of the device.

[0015] A tenth aspect includes a housing that is detachably mounted to the main body of the image forming device, that houses the brush inside, and that has an opening that exposes the contact portion of the brush with the rotating body, and a sealing portion that is detachably mounted to the housing and that seals the opening at both axial ends of the brush.

[0016] An eleventh aspect includes a housing that is detachably mounted on the main body of the image forming device, the housing containing the brush, and having an opening that exposes the contact portion of the brush with the rotating body; a transport member that, when rotated, transports toner that has fallen from the brush into the housing along the axial direction of the brush and discharges it from one end side of the housing in the axial direction; and an operating unit that, when the housing is removed from the main body of the image forming device, is connected to the transport member from the other end side of the housing in the axial direction and is operated by an operator to rotate the transport member. [Effects of the Invention]

[0017] According to the configuration of the first aspect, contamination of the non-transfer surface of the recording medium is suppressed compared to a configuration in which the blade is pressed against the outer peripheral surface of the rotating body to remove toner adhering to the outer peripheral surface.

[0018] According to the second aspect, the toner cloud is suppressed more effectively than in a configuration in which the brush rotates in the opposite direction to the rotation direction of the rotating body.

[0019] According to the configuration of the third aspect, the toner removal performance of the brush is improved compared to a configuration in which the peripheral speed ratio of the brush to the rotating body is 1 or less.

[0020] According to the fourth aspect of the configuration, the distance along the rotation direction of the rotating body from the contact position of the transfer section with the outer surface of the rotating body to the contact position of the brush with the outer surface of the rotating body is shorter than in a configuration in which the brush contacts the upstream portion.

[0021] According to the configuration of the fifth aspect, compared to a configuration in which the brush contacts only the rotating body, the re-adhesion of toner from the brush to the rotating body is suppressed.

[0022] According to the configuration of the sixth aspect, the re-adhesion of toner from the brush to the rotating body is suppressed more effectively than in a configuration in which the relationship KA≦KB is satisfied.

[0023] According to the seventh aspect, the distance along the rotation direction of the brush from the contact position of the brush with the outer circumferential surface of the rotor to the contact position of the contact member with the brush is shorter than in the configuration in which the contact member contacts the upstream portion.

[0024] According to the configuration of the eighth aspect, contamination of the non-transfer surface of the recording medium passing between the transfer unit and the rotating body is suppressed compared to a configuration in which the contact member is disposed above the brush.

[0025] According to the configuration of the ninth aspect, the cost of replacing parts is reduced compared to a configuration in which the brush is not detachable from the housing.

[0026] According to the configuration of the tenth aspect, the cost of replacing parts is reduced compared to a configuration in which the sealing portion is not detachable from the housing.

[0027] According to the configuration of the eleventh aspect, the mechanism for recovering the toner is simplified compared to a configuration in which toner that has fallen inside the housing is discharged from the housing when the housing is attached to the main body of the image forming device. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the configuration of the periphery of a transfer cylinder according to the present embodiment. [Figure 3] FIG. 2 is a perspective view showing a gripper according to the embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating a configuration of a cleaning device and a transfer cylinder according to the embodiment. [Figure 5] FIG. 2 is an enlarged view showing the configuration of the cleaning device according to the embodiment. [Figure 6] 10 is a schematic view showing a state in which the cleaning device main body according to the embodiment is located at a separated position. FIG. [Figure 7] 1 is a schematic diagram showing a brush and a flicker according to an embodiment of the present invention; [Figure 8] 10 is a schematic diagram showing a state in which a recessed portion of a transfer cylinder faces a brush in the cleaning device according to the embodiment. FIG. [Figure 9] FIG. 2 is a schematic view showing a duct of the cleaning device according to the embodiment. [Figure 10] FIG. 3 is a schematic view showing a partition plate of the cleaning device according to the embodiment. [Figure 11] FIG. 2 is a schematic view showing a front cover of the image forming apparatus main body according to the embodiment. [Figure 12] FIG. 2 is a schematic view showing a state in which a front cover of the image forming apparatus main body according to the present embodiment is open. [Figure 13] FIG. 2 is a perspective view showing a detachable unit according to the present embodiment. [Figure 14] FIG. 2 is an enlarged perspective view showing a part of the detachable unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] An example of an embodiment of the present invention will be described below with reference to the drawings.

[0030] (Image forming apparatus 10) The configuration of an image forming apparatus 10 according to this embodiment will be described. FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to this embodiment. Note that arrow H shown in each figure indicates the vertical direction, i.e., the up-down direction of the apparatus, arrow W indicates the horizontal direction, i.e., the width direction of the apparatus, and arrow D indicates the horizontal direction, i.e., the depth direction of the apparatus (front-rear direction of the apparatus). In particular, arrow DR is used to indicate the rear of the apparatus. The dimensional ratios in the H, W, and D directions between the parts shown in each figure may differ from the actual dimensional ratios.

[0031] 1 is an electrophotographic image forming apparatus that forms a toner image (an example of an image) on a recording medium P. Specifically, the image forming apparatus 10 includes an image forming section 214, a fixing device 30, a conveying mechanism 12, and a cleaning device 15. Below, each section of the image forming apparatus 10 (the image forming section 214, the fixing device 30, the conveying mechanism 12, and the cleaning device 15) will be described.

[0032] (Image forming unit 214) The image forming unit 214 has a function of forming a toner image (an example of an image) on the recording medium P by electrophotography. Specifically, as shown in FIG. 1, the image forming unit 214 has a toner image forming unit 222 that forms a toner image, and a transfer device 217 that transfers the toner image formed in the toner image forming unit 222 onto the recording medium P.

[0033] (Toner image forming unit 222) 1 is provided in plurality to form toner images for each color. In this embodiment, toner image forming units 222 are provided for a total of four colors: yellow (Y), magenta (M), cyan (C), and black (K). (Y), (M), (C), and (K) shown in FIG. 1 indicate components corresponding to the above colors.

[0034] Since the toner image forming units 222 for each color are configured in the same manner except for the toner used, the respective parts of the toner image forming unit 222(K) are denoted by reference numerals in FIG. 1 as a representative of the toner image forming units 222 for each color.

[0035] Specifically, each toner image forming unit 222 for each color has a photoconductor 224 that rotates in one direction (for example, counterclockwise in FIG. 1). Each toner image forming unit 222 for each color also has a charger 223, an exposure device 240, and a developing device 238.

[0036] In the toner image forming unit 222 for each color, a charger 223 charges a photoconductor 224. Furthermore, an exposure device 240 exposes the photoconductor 224 charged by the charger 223 to light, thereby forming an electrostatic latent image on the photoconductor 224. Furthermore, a development device 238 develops the electrostatic latent image formed on the photoconductor 224 by the exposure device 240, thereby forming a toner image.

[0037] (Transfer device 217) The transfer device 217 shown in FIG. 1 is a device that transfers the toner image formed in the toner image forming unit 222 onto the recording medium P. Specifically, the transfer device 217 performs primary transfer of the toner image of each color on the photoreceptor 224 onto a transfer belt 213 serving as an intermediate transfer body, superimposing the toner image, and then performs secondary transfer of the superimposed toner image onto the recording medium P. As shown in FIG. 1, the transfer device 217 includes the transfer belt 213, a primary transfer roll 226, and a transfer cylinder 250. The transfer cylinder 250 is an example of a rotating body, and the transfer belt 213 is an example of a transfer unit.

[0038] The primary transfer roll 226 is a roll that transfers the toner image of each color on the photoconductor 224 to the transfer belt 213 at a primary transfer position T1 between the photoconductor 224 and the primary transfer roll 226. In this embodiment, a primary transfer electric field is applied between the primary transfer roll 226 and the photoconductor 224, so that the toner image formed on the photoconductor 224 is transferred to the transfer belt 213 at the primary transfer position T1.

[0039] Toner images are transferred from the photoconductors 224 of each color onto the outer peripheral surface of the transfer belt 213. As shown in Fig. 1, the transfer belt 213 is endless and is wound around a plurality of rolls 232 and an opposing roll 234 so as to assume an inverted triangular shape when viewed from the front (viewed from the depth direction of the device). The transfer belt 213 rotates in the direction of arrow A when at least one of the plurality of rolls 232 is driven to rotate.

[0040] Transfer cylinder 250 is a transfer body that transfers the toner image transferred onto transfer belt 213 onto recording medium P at secondary transfer position T2 between opposing roll 234 and transfer cylinder 250. As shown in FIG. 1, transfer cylinder 250 is disposed below transfer belt 213 and facing transfer belt 213. This transfer cylinder 250 is formed in a circular shape in side view and has a recess 254 on its outer circumferential surface. This recess 254 houses gripper 24 and mounting member 23, which will be described later. This prevents contact between gripper 24 and mounting member 23 and transfer belt 213 when they pass through secondary transfer position T2. ​​The specific configuration of recess 254 will be described later.

[0041] As shown in Fig. 2, a pair of sprockets 25 are provided on both axial ends of the transfer cylinder 250. The pair of sprockets 25 are arranged coaxially with the transfer cylinder 250 and are configured to rotate integrally with the transfer cylinder 250. The transfer cylinder 250 and the pair of sprockets 25 are driven to rotate by a drive unit (not shown). Note that, hereinafter, the axial direction of the transfer cylinder 250 may be simply referred to as the "axial direction."

[0042] 4, the transfer cylinder 250 has a cylinder body 252 made of a metal material such as stainless steel or aluminum, and an elastic layer 256 wrapped around the outer periphery of the cylinder body 252. The elastic layer 256 may be, for example, a rubber layer made of foamed rubber.

[0043] In this embodiment, a secondary transfer electric field is applied between the opposing roll 234 and the transfer cylinder 250, and the toner image transferred to the transfer belt 213 is transferred to the recording medium P at the secondary transfer position T2. ​​The outer circumferential surfaces of the transfer belt 213 and the transfer cylinder 250 are in contact with each other at the secondary transfer position T2, and the toner image is transferred while the recording medium P is conveyed between the transfer belt 213 and the transfer cylinder 250 at the secondary transfer position T2 with the recording medium P sandwiched therebetween.

[0044] (fixing device 30) In this embodiment, the fixing device 30 functions as a device that fixes the toner image transferred to the recording medium P by the transfer cylinder 250 to the recording medium P. Specifically, as shown in FIG. 1 , the fixing device 30 has a pressure roll 31 and a heating roll 32.

[0045] In the fixing device 30, a heating roll 32 is disposed above the pressure roll 31. The heating roll 32 has a heat source 32A such as a halogen lamp inside the roll.

[0046] The pressure roll 31 has a recess 34 on its outer peripheral surface. This recess 34 is provided at one portion of the outer peripheral surface of the pressure roll 31 in the circumferential direction. Furthermore, the recess 34 is elongated along the axial direction of the pressure roll 31 and has a depth along the radial direction of the pressure roll 31. The recess 34 accommodates a gripper 24 and an attachment member 23, which will be described later. This prevents the gripper 24 and attachment member 23 from coming into contact with the heating roll 32 when they pass through the fixing position NP shown in FIG. 1.

[0047] A pair of sprockets 37 are provided on both axial ends of the pressure roll 31. The pair of sprockets 37 are arranged coaxially with the pressure roll 31 and are configured to rotate integrally with the pressure roll 31.

[0048] Then, in the fixing device 30, the recording medium P is sandwiched between the heating roll 32 and the pressure roll 31 at the fixing position NP and transported while being heated and pressurized, thereby fixing the toner image transferred to the recording medium P to the recording medium P.

[0049] (Transport mechanism 12) The transport mechanism 12 shown in Fig. 1 is a mechanism that transports a recording medium P. As shown in Fig. 1 and Fig. 2, the transport mechanism 12 has a pair of chains 22 and a gripper 24. Note that Fig. 1 shows only one of the pair of chains 22, and the chain 22 and gripper 24 are shown in a simplified form.

[0050] The pair of chains 22 is formed in a loop as shown in Fig. 1. The pair of chains 22 is arranged at an interval in the apparatus depth direction (direction D in the figure) as shown in Fig. 2. Each of the pair of chains 22 is wound around a pair of sprockets 25 provided on both axial ends of the transfer cylinder 250 and a pair of sprockets 37 (see Fig. 1) provided on both axial ends of the pressure roll 31. The transfer cylinder 250 and the pair of sprockets 25 are rotated together in rotation direction B (direction of arrow B), causing the chain 22 to revolve in circulation direction C (direction of arrow C).

[0051] 2, mounting members 23 to which grippers 24 are attached are hung across the pair of chains 22 in the depth direction of the device. A plurality of mounting members 23 are fixed to the pair of chains 22 at predetermined intervals along the circumferential direction C of the chains 22.

[0052] As shown in Fig. 2, a plurality of grippers 24 are attached to the mounting member 23 at predetermined intervals along the depth direction of the device. The grippers 24 function as holding parts that hold the leading end of the recording medium P. Specifically, as shown in Fig. 3, the grippers 24 have claws 24A and claw bases 24B. The grippers 24 are configured to hold the recording medium P by pinching the leading end of the recording medium P between the claws 24A and the claw bases 24B. Note that, for example, the grippers 24 have claws 24A pressed against the claw bases 24B by a spring or the like, and the claws 24A are opened and closed relative to the claw bases 24B by the action of a cam or the like.

[0053] In the conveying mechanism 12, the leading edge of the recording medium P sent from a storage unit (not shown) that stores the recording medium P is held by a gripper 24, as shown in FIG. 3. The gripper 24 holding the leading edge of the recording medium P conveys the recording medium P as the chain 22 rotates in the rotation direction C, and passes through the secondary transfer position T2 and the fixing position NP. Then, the toner images of each color that have been primarily transferred onto the transfer belt 213 in a superimposed state at the primary transfer position T1 are secondarily transferred onto the recording medium P at the secondary transfer position T2. ​​The toner images secondarily transferred onto the recording medium P are fixed to the recording medium P at the fixing position NP.

[0054] When passing through the secondary transfer position T2, the gripper 24 is accommodated together with the mounting member 23 in a recess 254 formed on the outer peripheral surface of the transfer cylinder 250, and when passing through the fixing position NP, the gripper 24 is accommodated together with the mounting member 23 in a recess 34 formed on the outer peripheral surface of the pressure roll 31.

[0055] (Cleaning device 15) Cleaning device 15 shown in Fig. 4 is a device that cleans the outer peripheral surface of transfer cylinder 250. Specifically, cleaning device 15 is a device that removes toner adhering to the outer peripheral surface of transfer cylinder 250. As shown in Fig. 4, cleaning device 15 includes a cleaning device main body 40, a movement mechanism 50, a duct frame 60, and an attachment / detachment unit 70. In this embodiment, the outer peripheral surface of transfer cylinder 250 refers to the surface of elastic layer 256.

[0056] (Cleaning device body 40 and moving mechanism 50) As shown in FIG. 5, the cleaning device main body 40 has a box-shaped housing 42 and an attachment portion 44. The housing 42 is formed in a substantially rectangular parallelepiped shape that is elongated along the axial direction. The housing 42 has an opening 42A that opens toward the transfer cylinder 250 (the right side in FIG. 5). In this embodiment, the cleaning device main body 40, including the duct frame 60 and the detachable unit 70, is provided in the main body 11 of the image forming apparatus 10 (hereinafter referred to as the "image forming device main body 11") so as to be movable along the device width direction. Specifically, the cleaning device main body 40 is movable along the device width direction between a close position shown in FIG. 4 and a separate position shown in FIG. 6.

[0057] At the approach position, when the outer peripheral surface of the transfer cylinder 250 faces the brush 72, the brush 72 comes into contact with the outer peripheral surface of the transfer cylinder 250. Also, when the outer peripheral surface of the transfer cylinder 250 faces a sealant 78 (described later), the sealant 78 comes into contact with the outer peripheral surface of the transfer cylinder 250. At the separated position, the brush 72 is separated from the outer peripheral surface of the transfer cylinder 250.

[0058] 5, the mounting portion 44 is a portion to which a tension spring 52 (described later) of the movement mechanism 50 is attached. Two mounting portions 44 are provided on the side wall 42B of the housing 42 on the opposite side from the transfer cylinder 250 (on the left side in FIG. 5).

[0059] The moving mechanism 50 moves the cleaning device body 40 between the approach position shown in FIG. 4 and the separated position shown in FIG. 6. Specifically, as shown in FIG. 5, the moving mechanism 50 has two tension springs 52 and a cam 54. One end of each of the two tension springs 52 is attached to the mounting portion 44, and the other end is attached to the mounting portion 13 provided on the image forming apparatus body 11. As a result, the two tension springs 52 pull the cleaning device body 40 toward the separated position (left side in FIG. 5) relative to the approach position. The cam 54 is provided on the image forming apparatus body 11 so as to be swingable about a swing shaft 54A. In the moving mechanism 50, the cam 54 swings, and the major diameter portion of the cam 54 comes into contact with the side wall 42B of the housing 42, thereby moving the cleaning device body 40 to the approach position shown in FIG. 4 against the elastic force of the tension spring 52.

[0060] In addition, in the moving mechanism 50, when the cam 54 swings and the minor axis portion of the cam 54 faces the side wall 42B of the housing 42, the elastic force of the tension spring 52 moves the cleaning device main body 40 to the separated position shown in FIG.

[0061] (Duct frame 60 and detachable unit 70) As shown in FIG. 5, the duct frame 60 and the detachable unit 70 are disposed inside the housing 42 of the cleaning device main body 40.

[0062] The detachable unit 70 is provided so as to be insertable into and removable from the cleaning device main body 40 provided in the image forming device main body 11 in the front-to-rear direction. Specifically, the detachable unit 70 is removed from the image forming device main body 11 by being pulled out from the cleaning device main body 40 toward the front side (the front side of the paper in FIG. 5 ), and is attached to the cleaning device main body 40 by being inserted from the front side to the rear side (the back side of the paper in FIG. 5 ). In this way, the detachable unit 70 is provided so as to be detachable from the image forming device main body 11.

[0063] Specifically, the detachable unit 70 has a box-shaped housing 80, a brush 72, a flicker 74, a transport auger 76, and sealants 78 and 79. The flicker 74 is an example of a contact member, and the transport auger 76 is an example of a transport member.

[0064] The housing 80 is formed in a generally rectangular parallelepiped shape that is elongated along the axial direction. The housing 80 has an opening 82 that opens toward the transfer cylinder 250 (the right side in FIG. 5). Specifically, the housing 80 has, for example, a side wall 81, an upper wall 89, an upper edge 83, inclined walls 84 and 86, a bottom wall 85, and a lower edge 87.

[0065] The side wall 81 is disposed on the opposite side of the brush 72 from the transfer cylinder 250 (left side in FIG. 5). The side wall 81 is formed as a plate extending in the up-down direction when viewed in the front-rear direction. The top wall 89 is formed as a plate extending from the upper end of the side wall 81 toward the transfer cylinder 250 (right side in FIG. 5) when viewed in the front-rear direction. The top edge 83 is formed as a plate extending diagonally downward from the right end of the top wall 89 (the end on the transfer cylinder 250 side; the same applies below) toward the transfer cylinder 250 (right side in FIG. 5) when viewed in the front-rear direction. The top edge 83 forms the upper edge of the opening 82.

[0066] The inclined wall 84 is formed in a plate shape extending obliquely downward from the lower end of the side wall 81 toward the transfer cylinder 250 (right side in FIG. 5) when viewed in the front-rear direction. The bottom wall 85 is formed in a plate shape extending from the lower end of the inclined wall 84 toward the transfer cylinder 250 (right side in FIG. 5) when viewed in the front-rear direction.

[0067] The inclined wall 86 is formed in a plate shape extending obliquely upward from the right end of the bottom wall 85 toward the transfer cylinder 250 (the right side in FIG. 5 ) when viewed in the front-rear direction. The lower edge 87 is formed in a plate shape extending upward from the upper end of the inclined wall 86 when viewed in the front-rear direction. The lower edge 87 forms the lower edge of the opening 82.

[0068] The brush 72 has a shaft portion 72A and a brush portion 72B provided on the outer periphery of the shaft portion 72A. The brush portion 72B is arranged around the entire circumference of the shaft portion 72A and is made of fibers extending radially outward from the shaft portion 72A. For example, resin fibers such as polyethylene terephthalate (PET) are used as the fibers. The fiber diameter of the fibers is, for example, 2d (denier) or more and 15d (denier) or less, and the fiber density is, for example, 10,000 fibers / inch. 2 More than 120000 pieces / inch 2 A part of the brush portion 72B in the circumferential direction is a contact portion that comes into contact with the outer peripheral surface of the transfer cylinder 250.

[0069] Specifically, brush 72 is housed inside housing 80, and the contact portion of brush portion 72B with transfer cylinder 250 is exposed through opening 82. The contact portion of brush portion 72B contacts the outer peripheral surface of transfer cylinder 250 at the approach position shown in FIG.

[0070] The shaft 72A of the brush 72 extends in the front-to-rear direction of the device, and both axial ends are rotatably supported by the cleaning device main body 40 via bearings 73 (see FIG. 14). The shaft 72A of the brush 72 is driven by a drive unit (not shown), and the brush 72 rotates in the forward direction relative to the rotation direction of the transfer cylinder 250. That is, while the transfer cylinder 250 rotates counterclockwise in FIG. 4, the brush 72 rotates clockwise in FIG. 4. The peripheral speed ratio of the brush 72 to the transfer cylinder 250 exceeds 1. That is, the peripheral speed of the brush 72 is faster than the peripheral speed of the transfer cylinder 250. In this embodiment, the peripheral speed ratio of the brush 72 to the transfer cylinder 250 is set, for example, in the range of more than 1 and not more than 2.5. The peripheral speed of the brush 72 is the peripheral speed at the tip of the portion that is not embedded in the transfer cylinder 250.

[0071] As the brush 72 rotates, each portion of the brush portion 72B in the circumferential direction repeatedly comes into contact with and separates from the outer peripheral surface of the transfer cylinder 250. The brush portion 72B, which is elastically deformed by contacting the outer peripheral surface of the transfer cylinder 250, elastically returns to its original shape, thereby repelling the toner adhering to the outer peripheral surface of the transfer cylinder 250 and physically removing the toner from the outer peripheral surface.

[0072] In addition to or instead of the physical removal, the brush 72 may be configured to remove toner from the outer peripheral surface of the transfer cylinder 250 by electrostatic force.

[0073] The flicker 74 is disposed below the brush 72 and is in contact with the brush portion 72B. The flicker 74 is formed in a rod shape with a circular cross section. When the flicker 74 comes into contact with the rotating brush 72, it causes the toner adhering to the brush 72 to fall. The fallen toner is contained inside the housing 80 and accumulates on the bottom wall 85 inside the housing 80.

[0074] In this embodiment, as shown in FIG. 7 , when KA denotes the amount of penetration of the brush 72 into the flicker 74 and KB denotes the amount of penetration of the brush 72 into the transfer cylinder 250, the relationship KA > KB holds. The penetration amount KA is the length of overlap between the brush 72 and the flicker 74 in the radial direction of the brush 72. The penetration amount KB is the length of overlap between the brush 72 and the transfer cylinder 250 in the radial direction of the brush 72. In this embodiment, the penetration amount KA is, for example, 0.5 mm or more and 3.0 mm or less, and the penetration amount KB is, for example, 0.3 mm or more and 2.8 mm or less. The length of the fibers of the brush portion 72B (i.e., the radial length) is, for example, 4 mm or more and 10 mm or less, and the distance between the shaft portion 72A of the brush 72 and the transfer cylinder 250 is, for example, 1.2 mm or more and 9.7 mm or less.

[0075] 5, the transport auger 76 is disposed on the bottom wall 85 inside the housing 80. The transport auger 76 has a shaft portion 76A and blade portions 76B spirally provided on the outer periphery of the shaft portion 76A.

[0076] Shaft 76A of transport auger 76 extends in the front-to-rear direction of the device, and both axial ends are rotatably supported by cleaning device main body 40. In transport auger 76, rotation of shaft 76A causes blades 76B to pivot, transporting toner that has fallen onto bottom wall 85 inside housing 80 rearward along the axial direction of brush 72, and discharging the toner from the rear side of housing 80 (an example of one axial end side) through discharge pipe 76C (see FIG. 13).

[0077] The sealing materials 78 and 79 have the function of preventing the toner contained inside the housing 80 from leaking out of the housing 80 through the opening 82 of the housing 80. The sealing materials 78 and 79 are made of, for example, a flexible film material.

[0078] As shown in Fig. 5, the sealant 78 is attached to the upper edge 83 of the housing 80. Specifically, the sealant 78 extends diagonally downward from the upper edge 83 toward the transfer cylinder 250 (to the right in Fig. 5), with its tip contacting the outer peripheral surface of the transfer cylinder 250. In this way, the sealant 78 prevents toner from leaking through the gap between the upper edge 83 of the housing 80 and the outer peripheral surface of the transfer cylinder 250.

[0079] The sealant 79 is attached to the lower edge 87 of the housing 80. Specifically, the sealant 79 extends upward from the lower edge 87, and its tip is in contact with the flicker 74. In this way, the sealant 79 prevents toner from leaking through the gap between the lower edge 87 of the housing 80 and the flicker 74.

[0080] The duct frame 60 is a frame that serves as a component that configures the ducts 91 and 92. In this embodiment, the ducts 91 and 92 are configured by the duct frame 60 and the housing 80 of the detachable unit 70. Specifically, the duct frame 60 has, for example, side walls 61 and 65, an upper wall 62, inclined walls 63 and 66, and a bottom wall 64.

[0081] The side wall 61 is disposed on the opposite side of the transfer cylinder 250 (left side in FIG. 5 ) from the side wall 81 of the housing 80 of the detachable unit 70. The side wall 61 is formed in a plate shape that extends in the vertical direction when viewed in the front-to-rear direction. Specifically, the side wall 61 extends above the top wall 89 and below the bottom wall 85 of the housing 80 of the detachable unit 70.

[0082] The upper wall 62 is formed in a plate shape extending from the upper end of the side wall 61 toward the transfer cylinder 250 (to the right in FIG. 5) when viewed in the front-rear direction. The inclined wall 63 is formed in a plate shape extending diagonally downward from the right end of the upper wall 62 toward the transfer cylinder 250 (to the right in FIG. 5) when viewed in the front-rear direction.

[0083] The bottom wall 64 is formed in a plate shape extending from the lower end of the side wall 61 toward the transfer cylinder 250 (to the right in FIG. 5) when viewed in the front-rear direction. The side wall 65 is formed in a plate shape extending upward from the right end of the bottom wall 64 when viewed in the front-rear direction. The inclined wall 66 is formed in a plate shape extending diagonally upward from the upper end of the side wall 65 toward the transfer cylinder 250 (to the right in FIG. 5) when viewed in the front-rear direction.

[0084] The duct 91 is disposed above the brush 72 and above the top wall 89 of the housing 80. The duct 91 is composed of the top wall 89 and upper edge 83 of the housing 80, and the upper portion of the side wall 61, the top wall 62, and the inclined wall 63 of the duct frame 60. The duct 91 has a suction port 91A between the top edge 83 of the housing 80 and the inclined wall 63 of the duct frame 60. The suction port 91A opens toward the transfer cylinder 250. As shown in FIG. 8 , when the recess 254 of the transfer cylinder 250 is rotated to face the brush 72 (the left side in FIG. 5 ), the suction port 91A faces the recess 254. Furthermore, the suction port 91A is disposed between the transfer belt 213 (secondary transfer position T2) and the brush 72. That is, the suction port 91A opens below the transfer belt 213 (secondary transfer position T2) and above the brush 72. Furthermore, the duct 91 extends in the front-rear direction as shown in Fig. 9. A front wall 67 that closes the front of the duct 91 is provided on the front side of the duct 91.

[0085] Furthermore, a partition plate 93 is provided inside the duct 91, as shown in FIG. 5. Specifically, the partition plate 93 is disposed between the suction port 91A and the side wall 61, and between the upper wall 62 of the duct frame 60 and the upper wall 89 of the housing 80. The partition plate 93 divides the interior of the duct 91 into a space 91X on the suction port 91A side and a space 91Y on the side wall 61 side. As shown in FIG. 10, the partition plate 93 has a plurality of openings 93A formed therein. The opening area of ​​the openings 93A at the rear end of the partition plate 93 is smaller than the opening area of ​​the openings 93A at the front end of the partition plate 93. Specifically, the plurality of openings 93A are gradually reduced in size and spaced apart from one another from the front to the rear.

[0086] As shown in FIG. 5, the duct 92 is disposed below the brush 72 and below the bottom wall 85 of the housing 80. The duct 92 is composed of the inclined walls 84 and 86, the bottom wall 85, and the lower edge 87 of the housing 80, and the lower part of the side wall 61, the bottom wall 64, the side wall 65, and the inclined wall 66 of the duct frame 60. The duct 92 has a suction port 92A between the lower edge 87 of the housing 80 and the inclined wall 66 of the duct frame 60. The suction port 92A opens toward the transfer cylinder 250. As shown in FIG. 8, when the recess 254 of the transfer cylinder 250 is rotated to face the brush 72 (the left side in FIG. 5), the suction port 92A faces the recess 254. Furthermore, the suction port 92A is disposed on the opposite side of the brush 72 from the transfer belt 213 (secondary transfer position T2). That is, the suction port 92A opens below the brush 72. The duct 92 extends in the front-to-rear direction as shown in Fig. 9. A front wall 68 that closes the front of the duct 92 is provided on the front side of the duct 92.

[0087] Furthermore, a partition plate 94 is provided inside the duct 92, as shown in Fig. 5. Specifically, the partition plate 94 is disposed between the suction port 92A and the bottom wall 64, and between the side wall 65 of the duct frame 60 and the bottom wall 85 of the housing 80. The partition plate 94 divides the inside of the duct 92 into a space 92X on the suction port 92A side and a space 92Y on the bottom wall 64 side. The partition plate 94 has an opening 94A, similar to the partition plate 93 (see Fig. 10).

[0088] As shown in Fig. 9, the ducts 91 and 92 are connected at the rear side, and one end of a flexible tube 95 such as a hose is connected to the side wall 61 side of the connected portion (i.e., the space 91Y and space 92Y side, see Fig. 5). The other end of the tube 95 is connected to a housing portion 97 that houses a filter 96. The filter 96 can be pulled out from the housing portion 97 in the direction of arrow M and can be replaced with a new filter 96.

[0089] Furthermore, a blower 98 is provided below the storage section 97. When the blower 98 is driven, air containing toner is drawn into the duct 91 through the suction port 91A and into the duct 92 through the suction port 92A. The air drawn into the duct 91 flows rearward while passing through an opening 93A of the partition plate 93. The air drawn into the duct 92 flows rearward while passing through an opening 94A of the partition plate 94, merges with the air that has flowed through the duct 91, and is discharged through a pipe 95 and a filter 96. In this embodiment, the rear side of the ducts 91 and 92 is the suction side of the blower 98, and therefore, by reducing the opening area of ​​the partition plates 93 and 94 at their rear ends, variation in the air volume in the front-to-rear direction is suppressed.

[0090] (Positional relationship of each part of the cleaning device 15) 4, secondary transfer position T2 is located above brush 72 and above transfer cylinder 250. When the outer peripheral surface of transfer cylinder 250 is equally divided into a downstream portion and an upstream portion in the rotation direction of transfer cylinder 250 based on secondary transfer position T2, brush 72 is in contact with the downstream portion (the portion on the left half in FIG. 4). Furthermore, when the positions of secondary transfer position T2 and brush 72 relative to transfer cylinder 250 are considered to correspond to the face of a clock, if secondary transfer position T2 is the 12 o'clock position on transfer cylinder 250, brush 72 is located, for example, between 8 o'clock and 10 o'clock.

[0091] Furthermore, when brush 72 is equally divided into a downstream portion and an upstream portion in the rotation direction based on contact position 72S of brush 72 with the outer circumferential surface of transfer cylinder 250, flicker 74 contacts the downstream portion. In other words, flicker 74 contacts the lower half of brush 72. Furthermore, when contact position 72S of brush 72 with transfer cylinder 250 and the position of flicker 74 are considered to correspond to the face of a clock, if contact position 72S is the 3 o'clock position on brush 72, flicker 74 is located, for example, between 4 o'clock and 6 o'clock.

[0092] Furthermore, the secondary transfer position T2 is disposed above the brush 72, whereas the flicker 74 is disposed below the brush 72. In other words, the flicker 74 is disposed on the opposite side of the brush 72 from the side where the secondary transfer position T2 is disposed.

[0093] (Relationship between each part of the cleaning device 15 and the recessed part 254 of the transfer cylinder 250) 8, one recess 254 is provided on the transfer cylinder 250 at a portion of the circumferential direction on the outer peripheral surface of the transfer cylinder 250. This recess 254 is elongated along the axial direction of the transfer cylinder 250 and has a depth along the radial direction of the transfer cylinder 250.

[0094] An opening width 254L of the recess 254 as viewed in the axial direction (see FIG. 8) is wider than a contact width SL (see FIG. 7) between the brush 72 and the outer peripheral surface of the transfer cylinder 250 as viewed in the axial direction. Furthermore, a depth 254D of the recess 254 (see FIG. 8) is deeper than a penetration depth KB of the brush 72 into the transfer cylinder 250 (see FIG. 7). Therefore, when the brush 72 faces the recess 254, the brush 72 is out of contact with the transfer cylinder 250, and the state of penetration into the transfer cylinder 250 is released. Furthermore, the opening width 254L of the recess 254 is wider than the outer diameter of the brush 72, wider than an opening width 80L of the opening 82 of the housing 80 as viewed in the axial direction, and wider than a width 60L between the tip of the inclined wall 63 and the tip of the inclined wall 66 of the duct frame 60 as viewed in the axial direction. The opening width 254L, the contact width SL, the opening width 80L, and the width 60L are widths along the circumferential direction of the transfer cylinder 250.

[0095] (Configuration of the detachable unit 70 and configuration for attaching and detaching the detachable unit 70) 11 and 12, the detachable unit 70 including the housing 80 can be attached and detached by swinging the lever 11A provided on the image forming apparatus main body 11 from the closed position shown in Fig. 11 to the open position shown in Fig. 12 and tilting the front cover 11B forward to open it. Specifically, the detachable unit 70 including the housing 80 can be attached and detached as follows.

[0096] In this embodiment, the pivot shaft of the lever 11A is integral with the pivot shaft 54A of the cam 54. By pivoting the lever 11A to the open position, the cam 54 pivots, and the minor axis of the cam 54 faces the side wall 42B of the housing 42. The elastic force of the tension spring 52 moves the cleaning device main body 40 to the separated position shown in FIG. 6. The front cover 11B is disposed in front of the detachable unit 70 in the separated position, and opening the front cover 11B makes the detachable unit 70 detachable. In this embodiment, the detachable unit 70, including the housing 80, can be removed from the cleaning device main body 40 while the duct frame 60 that forms the ducts 91 and 92 remains in the cleaning device main body 40.

[0097] 12 and 13, a handle 70A is provided on the front of the detachable unit 70, and by pulling the handle 70A, the detachable unit 70 can be pulled out from the image forming apparatus main body 11. A box-shaped structure 70E provided with the handle 70A is detachable from the housing 80 (see FIG. 14). Furthermore, as shown in FIG. 13, a handle 70B for carrying is provided on the top of the detachable unit 70. Note that the flicker 74 is not shown in FIG. 13.

[0098] As shown in Fig. 13, the detachable unit 70 has side sealing members 71 that seal the opening 82 of the housing 80 on both axial ends of the brush 72. The side sealing members 71 are detachably provided on the housing 80. Specifically, as shown in Fig. 14, the side sealing members 71 are attached by being fastened to the housing 80 with screws 77, and can be removed from the housing 80 by removing the screws 77. The side sealing members 71 are an example of a sealing portion.

[0099] Bearings 73, which support both ends of shaft portion 72A of brush 72, are detachably provided in housing 80. Specifically, as shown in Fig. 14 , bearings 73 are attached by being fastened to housing 80 with screws 75, and by removing screws 75, bearings 73 can be removed in the direction of arrow Z from the opening 82 side of housing 80 in a state in which side sealing material 71 and structure 70E have been removed.

[0100] The side sealing material 71 and the brush 72 are detachable from the housing 80 when the detachable unit 70 is removed from the image forming apparatus main body 11.

[0101] Furthermore, a connecting portion 76S is provided at the front end of the shaft portion 76A (see FIG. 5) of the transport auger 76. As shown in FIG. 14, when the detachable unit 70 is detached from the image forming apparatus main body 11 and the structure 70E is detached, a handle 99 is connected to the connecting portion 76S of the shaft portion 76A from the front side. An operator operates the handle 99 to rotate the transport auger 76. As a result, a storage bag or the like is attached to the discharge pipe 76C (see FIG. 13) on the rear side of the housing 80, and toner is discharged into the storage bag through the discharge pipe 76C. The handle 99 is an example of an operating portion.

[0102] (Action of this embodiment) According to this embodiment, as described above, the toner adhering to the outer peripheral surface of the transfer cylinder 250 is removed by the brush 72 that contacts the outer peripheral surface of the transfer cylinder 250 (see FIG. 4).

[0103] Here, in a configuration (hereinafter referred to as configuration A) in which a blade is pressed against the outer peripheral surface of transfer cylinder 250 to remove toner adhering to the outer peripheral surface, recesses 254 are formed in the outer peripheral surface of transfer cylinder 250, and so the blade may collide with the edge of recesses 254, causing vibrations in the blade and transfer cylinder 250. When vibrations occur in the blade and transfer cylinder 250, toner adhering to the blade and transfer cylinder 250 may fly up and adhere to the non-transfer surface of recording medium P passing through secondary transfer position T2, possibly soiling the non-transfer surface.

[0104] Furthermore, in the above-described configuration A, recesses 254 formed on the outer peripheral surface of transfer cylinder 250 face the blade, which causes the blade's posture to change easily and the force of the blade pressing against the outer peripheral surface to fluctuate. As a result, in configuration A, toner may not be completely removed from the outer peripheral surface, and toner may remain on the outer peripheral surface. If toner remains on the outer peripheral surface of transfer cylinder 250, the toner on the outer peripheral surface may adhere to the non-transfer surface of recording medium P passing through secondary transfer position T2, causing the non-transfer surface to become dirty.

[0105] In contrast, in this embodiment, brush 72 is used to remove toner adhering to the outer peripheral surface of transfer cylinder 250, which reduces fluctuations in contact pressure with transfer cylinder 250 and vibrations at the edges of recessed portion 254, compared to configuration A. Therefore, in this embodiment, contamination of the non-transfer surface of the recording medium is reduced, compared to configuration A.

[0106] In this embodiment, the brush 72 rotates in the forward direction relative to the rotation direction of the transfer cylinder 250. In a configuration in which the brush 72 rotates in the reverse direction relative to the rotation direction of the transfer cylinder 250 (hereinafter referred to as configuration B), the brush 72 rotates against the rotation direction of the transfer cylinder 250, so the fibers of the brush 72 are repelled more than in the forward direction, and toner adhering to the brush 72 is more likely to fly up. When configuration B is adopted in this embodiment, the brush 72 moves upward at the contact portion with the transfer cylinder 250, and toner is particularly likely to fly up. In addition, when configuration B is adopted, because toner is more likely to fly up, it is possible to consider using the brush at a lower rotation speed. However, in this case, the number of times the brush 72 comes into contact with the flicker 74 decreases, and the ability to remove toner from the brush 72 decreases.

[0107] In contrast, in this embodiment, as described above, the brush 72 rotates in the forward direction relative to the rotation direction of the transfer cylinder 250, so toner is less likely to fly up compared to configuration B, and toner clouds are suppressed.

[0108] In addition, in this embodiment, the peripheral speed ratio of the brush 72 to the transfer cylinder 250 exceeds 1, so the toner removal performance of the brush 72 is improved compared to a configuration in which the peripheral speed ratio of the brush 72 to the transfer cylinder 250 is 1 or less.

[0109] Furthermore, in this embodiment, as shown in FIG. 4, when the outer peripheral surface of the transfer cylinder 250 is equally divided into a downstream portion and an upstream portion in the rotation direction of the transfer cylinder 250 based on the secondary transfer position T2, the brush 72 is in contact with the downstream portion (the portion on the left half side in FIG. 5).

[0110] Therefore, compared to a configuration in which brush 72 contacts the upstream portion, the distance along the rotation direction of transfer cylinder 250 from secondary transfer position T2 to the position where brush 72 contacts the outer circumferential surface of transfer cylinder 250 is shorter. As a result, after toner adheres to transfer cylinder 250 at secondary transfer position T2, the toner is quickly removed by brush 72, thereby suppressing the generation of toner clouds from transfer cylinder 250.

[0111] In addition, in this embodiment, the flicker 74 comes into contact with the rotating brush 72, causing the toner adhering to the brush 72 to fall off. Therefore, compared to a configuration in which the brush 72 contacts only the transfer cylinder 250, the re-adhesion of toner from the brush 72 to the transfer cylinder 250 is suppressed.

[0112] 7, in this embodiment, when the amount of penetration of brush 72 into flicker 74 is KA and the amount of penetration of brush 72 into transfer cylinder 250 is KB, the relationship KA>KB is satisfied. Therefore, compared to a configuration where the relationship KA≦KB, toner that has moved from transfer cylinder 250 to brush 72 is more likely to fall from brush 72, and re-adhesion of toner from brush 72 to transfer cylinder 250 is suppressed.

[0113] In this embodiment, when the brush 72 is equally divided into a downstream portion and an upstream portion in the rotation direction based on the contact position of the brush 72 with the outer circumferential surface of the transfer cylinder 250, the flicker 74 comes into contact with the downstream portion. In other words, the flicker 74 comes into contact with the lower half of the brush 72.

[0114] Therefore, compared to a configuration in which the flicker 74 contacts the upstream portion, the distance along the rotation direction of the brush 72 from the contact position of the brush 72 with the outer circumferential surface of the transfer cylinder 250 to the contact position of the flicker 74 with the brush 72 is shorter. As a result, after toner adheres to the brush 72 at the contact position with the transfer cylinder 250, the toner falls off the brush 72 in a short time, thereby suppressing the generation of toner clouds from the brush 72.

[0115] In this embodiment, the secondary transfer position T2 is disposed above the brush 72, whereas the flicker 74 is disposed below the brush 72.

[0116] Therefore, compared to a configuration in which the flicker 74 is positioned above the brush 72, the toner cloud generated at the contact position between the flicker 74 and the brush 72 is prevented from contaminating the non-transfer surface of the recording medium P passing through the secondary transfer position T2.

[0117] In this embodiment, the brush 72 is provided in the housing 80 so as to be detachable from the housing 80 of the detachable unit 70 when it is removed from the image forming apparatus main body 11. Therefore, the brush 72 can be replaced independently, and the cost of replacing parts is reduced compared to a configuration in which the brush 72 is not detachable from the housing 80.

[0118] In addition, in this embodiment, the side seals 71 that seal the opening 82 of the housing 80 on both axial ends of the brush 72 are detachably provided on the housing 80. Therefore, the side seals 71 can be replaced independently, and the cost of replacing parts is reduced compared to a configuration in which the side seals 71 are not detachable from the housing 80.

[0119] In this embodiment, when the detachable unit 70 is removed from the image forming apparatus main body 11, the operator rotates the handle 99 connected to the connection part 76S of the conveying auger 76, thereby discharging the toner that has fallen inside the housing 80.

[0120] Therefore, the mechanism for recovering the toner is simplified compared to a configuration in which toner that has fallen into the housing 80 is discharged from the housing 80 when the detachable unit 70 is attached to the image forming apparatus main body 11. Specifically, the drive unit for the transport auger 76 and the storage unit for storing the toner are not required.

[0121] (Variation) In this embodiment, the transfer belt 213 is used as an intermediate transfer body as an example of the transfer unit, but is not limited to this. As an example of the transfer unit, a photosensitive body or a direct transfer type transfer unit may be used.

[0122] Furthermore, in this embodiment, the brush 72 rotates in the forward direction relative to the rotation direction of the transfer cylinder 250, but this is not limited to this. For example, the brush 72 may be configured to rotate in the reverse direction relative to the rotation direction of the transfer cylinder 250. Alternatively, the brush 72 may not rotate. In this case, for example, the flicker 74 is not necessary.

[0123] In addition, in this embodiment, the peripheral speed ratio of the brush 72 to the transfer cylinder 250 exceeds 1, but this is not limiting. The peripheral speed ratio of the brush 72 to the transfer cylinder 250 may be 1 or less.

[0124] 4, when the outer peripheral surface of transfer cylinder 250 is equally divided into a downstream portion and an upstream portion in the rotation direction of transfer cylinder 250 with secondary transfer position T2 as a reference, brush 72 contacts the downstream portion (the portion on the left half side in FIG. 4), but this is not limiting. For example, brush 72 may be configured to contact the upstream portion.

[0125] Furthermore, in this embodiment, the flicker 74 is provided, but the flicker 74 may not be provided.

[0126] 7, in this embodiment, when the amount of penetration of the brush 72 into the flicker 74 is KA and the amount of penetration of the brush 72 into the transfer cylinder 250 is KB, the relationship KA>KB is satisfied, but this is not limiting. For example, the relationship KA≦KB may be satisfied.

[0127] In this embodiment, when the brush 72 is equally divided into a downstream portion and an upstream portion in the rotation direction based on the contact position of the brush 72 with the outer circumferential surface of the transfer cylinder 250, the flicker 74 contacts the downstream portion, but this is not limiting. For example, the flicker 74 may be configured to contact the upstream portion.

[0128] In addition, in this embodiment, the secondary transfer position T2 is disposed above the brush 72, whereas the flicker 74 is disposed below the brush 72. However, this is not limiting. For example, the flicker 74 may be disposed above the brush 72.

[0129] In addition, in the present embodiment, the brush 72 is provided in the housing 80 so as to be detachable from the housing 80 of the detachable unit 70 in a state where the detachable unit 70 is removed from the image forming apparatus main body 11, but this is not limited to this. For example, the brush 72 may be configured to be non-detachable from the housing 80, and the entire detachable unit 70 may be a replaceable unit.

[0130] In addition, in the present embodiment, the side sealants 71 that seal the opening 82 of the housing 80 at both axial ends of the brush 72 are detachably provided on the housing 80, but this is not limiting. For example, the side sealants 71 may be configured to be non-detachable from the housing 80, and the entire detachable unit 70 may be replaced as a unit.

[0131] In addition, in the present embodiment, when the detachable unit 70 is detached from the image forming apparatus main body 11, the toner that has fallen into the housing 80 is discharged by the operator rotating the handle 99 connected to the connection portion 76S of the transport auger 76, but this is not limiting. For example, when the detachable unit 70 is attached to the image forming apparatus main body 11, the toner that has fallen into the housing 80 may be discharged from the housing 80.

[0132] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit of the present invention. For example, the above-described modified examples may be appropriately combined to form a configuration. [Explanation of symbols]

[0133] 10 Image forming device 71 Side sealing material (example of sealing part) 72 Brushes 74 Flicker (an example of a contact element) 76 Conveying auger (an example of a conveying member) 80 cabinets 99 Handle (an example of an operating part) 213 Transfer belt (an example of a transfer unit) 250 Transfer cylinder (an example of a rotating body) 254 recess P Recording medium

Claims

1. a rotor having a recess formed on its outer circumferential surface; a transfer unit that is disposed above the rotating body and faces the rotating body, the transfer unit having an outer peripheral surface that contacts the outer peripheral surface of the rotating body, conveying the recording medium while sandwiching the recording medium between the rotating body and the transfer unit, and transferring the toner held on the outer peripheral surface of the transfer unit onto the recording medium; a housing having an upper wall whose gap with the outer circumferential surface of the rotating body is sealed by a sealing portion, and a bottom wall having a gap between it and the outer circumferential surface of the rotating body; a brush that comes into contact with the outer peripheral surface of the rotating body to remove toner adhering to the outer peripheral surface, and that is accommodated inside the housing, with a contact portion with the rotating body exposed from an opening of the housing, the brush being located closer to the sealing portion than a gap between the outer peripheral surface of the rotating body and the bottom wall; Equipped with The depth of the recess is greater than the amount of penetration of the brush into the rotating body. Image forming device.

2. The opening width of the recess as viewed in the rotation axis direction of the rotor is wider than the contact width between the brush and the rotor as viewed in the rotation axis direction. The image forming apparatus according to claim 1 .

3. The brush rotates in the forward direction relative to the rotation direction of the rotor.

3. The image forming apparatus according to claim 1 or 2.

4. The peripheral speed ratio of the brush to the rotating body is greater than 1. The image forming apparatus according to claim 3 .

5. When the outer peripheral surface of the rotating body is divided equally into a downstream portion and an upstream portion in the rotation direction of the rotating body based on the contact position of the transfer portion with respect to the outer peripheral surface of the rotating body, the brush contacts the downstream portion. The image forming apparatus according to any one of claims 1 to 4.

6. The brush rotates, A contact member is provided to contact the rotating brush and cause the toner adhering to the brush to fall off. The image forming apparatus according to any one of claims 1 to 5.

7. When the amount of penetration of the brush into the contact member is KA and the amount of penetration of the brush into the rotating body is KB, the relationship KA>KB holds. The image forming apparatus according to claim 6 .

8. When the brush is equally divided into a downstream portion and an upstream portion in the rotation direction based on the contact position of the brush with respect to the outer circumferential surface of the rotating body, the contact member contacts the downstream portion.

8. The image forming apparatus according to claim 6 or 7.

9. a contact position of the transfer unit with the outer circumferential surface of the rotating body is disposed above the brush, The contact member is disposed below the brush. The image forming apparatus according to any one of claims 6 to 8.

10. The housing is detachably provided on the main body of the image forming apparatus, The brush is detachably attached to the housing when the housing is removed from the device main body. The image forming apparatus according to any one of claims 1 to 9.

11. The housing is detachably provided on the main body of the image forming apparatus, The housing is provided with other removably sealing portions that seal the openings on both axial end sides of the brush. The image forming apparatus according to any one of claims 1 to 10.

12. The housing is detachably provided on the main body of the image forming apparatus, a conveying member that conveys the toner that has fallen from the brush into the housing along the axial direction of the brush by rotation and discharges the toner from one end side of the housing in the axial direction; an operating unit that is connected to the conveying member from the other end side of the housing in the axial direction when the housing is detached from the device main body, and that is operated by an operator to rotate the conveying member; Equipped with The image forming apparatus according to any one of claims 1 to 11.

Images