JP2024079115A - Cleaning unit - Google Patents

Abstract

[Problem] To provide a cleaning unit capable of maintaining proper support of a bearing supporting a cleaning roller by a frame even when the cleaning roller moves in the axial direction. [Solution] The cleaning unit 7 includes a belt cleaning roller 71 extending along an axis X, a frame 70 supporting the belt cleaning roller 71 and including a first side wall 70A located on one end side in the axial direction X, a bearing 80 supporting one end 71A of the belt cleaning roller 71 on the first side wall 70A, the bearing 80 having a first rib 802 located on one side in the axial direction X of the first side wall 70A and a third rib 803 located on the other side in the axial direction X of the first side wall 70A, and a cover 90 covering the bearing 80 from one side in the axial direction X, the cover 90 including a second rib 902 located at a position overlapping the first rib 802 when projected in the axial direction X and capable of abutting against the first rib 802. [Selected Figure] Fig. 5

Description

The present invention relates to a cleaning unit.

Conventionally, electrophotographic image forming devices that form images by transferring a toner image carried by a photosensitive drum onto a sheet are equipped with a cleaning unit that collects residual developer on the photosensitive drum via a belt that contacts the photosensitive drum, as disclosed in, for example, Patent Document 1.

The cleaning unit includes a cleaning roller that removes developer adhering to the belt that contacts the photosensitive drum, a frame that supports the cleaning roller, a bearing that is interposed between the shaft of the cleaning roller and the frame, and a cover that covers the bearing. The bearing has a stopper that restricts axial movement of the bearing by contacting the frame in the axial direction of the shaft.

JP 2016-71213 A

In the above-mentioned cleaning unit, if the cleaning roller moves in the axial direction, for example when the packaged unit is dropped, the moving cleaning roller may place an excessive load on the bearing in the axial direction, damaging the bearing retainer, which may result in the bearing no longer being properly supported by the frame.

The present invention provides a cleaning unit that can maintain proper support from the bearing frame that supports the cleaning roller, even when the cleaning roller that removes developer adhering to the object to be cleaned moves in the axial direction.

The cleaning unit that solves the above problems has the following features:

That is, the cleaning unit includes a cleaning roller that removes developer adhering to an object to be cleaned, extends along an axis, and has one end and the other end in the axial direction; a frame that supports the cleaning roller and has one side wall located on the one end side in the axial direction; a bearing that rotatably supports the one end of the cleaning roller on the one side wall, the bearing having a first rib located on one side in the axial direction of the one side wall of the frame and a third rib located on the other side in the axial direction of the one side wall of the frame and capable of engaging with the one side wall; and a cover that covers the bearing from one side in the axial direction, the cover being located at a position that overlaps with the first rib when projected in the axial direction and having a second rib that can abut against the first rib.

As a result, when the cleaning roller moves in the axial direction due to, for example, the cleaning unit being dropped while packaged, the first rib comes into contact with the second rib, allowing the cover to support the axial load on the bearing. This prevents the third rib of the bearing from being damaged by an excessive load, and ensures that the bearing is properly supported by one side wall of the frame.

In addition, in the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first distance therebetween, and the one side wall of the frame and the third rib are positioned with a second distance therebetween, and the first distance is greater than the second distance.

As a result, when a load is applied to the cleaning unit in a direction that causes the cleaning roller to move to one side in the axial direction, the axial load acting on the third rib is reduced, preventing damage to the third rib and maintaining proper support of the bearing by one side wall of the frame.

The first distance is greater than or equal to 0.1 mm and less than or equal to 1.0 mm.

This prevents the bearing from moving too far to one side in the axial direction and damaging the third rib when an axial load is applied to the bearing, and ensures that the bearing is properly supported by one side wall of the frame.

Furthermore, the first distance is greater than or equal to 0.4 mm and less than or equal to 0.6 mm.

This prevents the bearing from moving too far to one side in the axial direction and damaging the third rib when an axial load is applied to the bearing, and ensures that the bearing is properly supported by one side wall of the frame.

In addition, in the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first distance therebetween, and the bearing has a protruding portion that protrudes from the one side wall of the frame to the other side in the axial direction when the one side wall of the frame and the first rib are in contact with each other, and the first distance is equal to or less than the length of the protruding portion in the axial direction.

As a result, when an axial load is applied to the bearing and the bearing moves axially to one side, even if the third rib abutting against the one side wall is damaged, the bearing can be prevented from coming out of the one side wall. This makes it possible to maintain proper support of the bearing by the one side wall of the frame.

The bearing is formed in a cylindrical shape extending in the axial direction, and includes a cylindrical rib with the first rib located at one end in the axial direction and the third rib located at the other end in the axial direction, and the protrusion is a part of the cylindrical rib.

This allows the bearing to be properly supported by one side wall of the frame even if the bearing moves in the axial direction.

In addition, in the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first distance therebetween, and the one side wall of the frame and the third rib are positioned with a second distance therebetween, and the second distance is greater than the first distance.

As a result, the second rib of the cover abuts against the first rib of the bearing before the third rib engages with the side wall of the frame, allowing the cover to support the axial load on the bearing. This prevents the third rib from being damaged by the axial load, and ensures that the side wall of the frame properly supports the bearing.

The cleaning roller also includes a conductive bearing attached to one side of the bearing in the axial direction, and the second rib has an arc shape that is arranged to surround the outer periphery of the conductive bearing.

As a result, the second rib is positioned on a portion of the conductive bearing's outer periphery rather than the entire circumference, allowing for greater freedom when placing components on the conductive bearing's outer periphery.

The cover also includes an electrode that is supported on the one side wall of the frame and is electrically connected to the cleaning unit, and the cover has a pressing rib that presses the electrode from one side in the axial direction, and the pressing rib and the second rib are formed continuously.

This improves the strength of the retaining rib and the second rib.

The cover also has an escape groove recessed toward one side in the axial direction at a position facing the conductive bearing in the axial direction.

As a result, when the conductive bearing attached to the cleaning roller moves to one side in the axial direction together with the cleaning roller, the conductive bearing can be accommodated in the escape groove, preventing interference between the conductive bearing and the cover.

The cleaning roller also has a shaft extending along the axial direction, and the cover has an escape hole penetrating in the axial direction at a position opposite the shaft in the axial direction.

As a result, when the shaft moves to one side in the axial direction, the shaft can protrude to one side of the cover in the axial direction through the escape hole, preventing interference between the shaft and the cover.

The diameter of the escape groove is larger than the diameter of the conductive bearing, and the diameter of the escape hole is larger than the diameter of one end of the shaft in the axial direction and smaller than the diameter of the conductive bearing.

This prevents the conductive bearing housed in the relief groove from passing through the relief hole and protruding to one side in the axial direction of the cover.

The cover also has a contact surface that comes into contact with packaging material for packaging the cleaning unit.

This allows the packing material to support the load on the cover when it is applied to the cover via the contact surface.

The contact surface is located at a position where the second rib on the cover is projected in the axial direction.

This allows the packaging material to effectively support the load from the cleaning roller.

The conductive bearing also has multiple ribs formed on one side in the axial direction and extending radially.

This makes it easy to confirm that the conductive bearing is installed in the correct orientation when it is attached to the cleaning roller.

According to the present invention, even if the cleaning roller moves in the axial direction, the bearing frame that supports the cleaning roller can maintain proper support.

FIG. 2 is a central cross-sectional view showing the image forming apparatus. FIG. 2 is a perspective view showing a cleaning unit. FIG. 4 is a side cross-sectional view showing the cleaning unit. FIG. 4 is a side view showing the right end portion of the cleaning unit. FIG. 4 is a plan cross-sectional view showing the right end portion of the cleaning unit. FIG. FIG. 2 illustrates a conductive bearing. FIG. 5 is a plan cross-sectional view showing the vicinity of a support portion for a shaft of the belt cleaning roller by a first side wall of the frame. FIG.

Next, the embodiment of the present invention will be described with reference to the attached drawings.

[Image forming apparatus]
An image forming apparatus 1 shown in FIG. 1 is one embodiment of an image forming apparatus equipped with a cleaning unit according to the present invention, and is a color laser printer that forms a multi-color image on a sheet S by electrophotography.

In the following description, the right side in FIG. 1 is defined as the front side of the image forming apparatus 1, the left side in FIG. 1 is defined as the rear side of the image forming apparatus 1, the front side of the paper in FIG. 1 is defined as the left side of the image forming apparatus 1, and the back side of the paper in FIG. 1 is defined as the right side of the image forming apparatus 1. In addition, the top and bottom sides in FIG. 1 are defined as the top and bottom sides of the image forming apparatus 1, respectively.

The image forming device 1 includes a device main body 2, a paper feed section 3 having a paper feed tray 10 that supports sheets S and a sheet transport section 30 that transports the sheets S, and an image forming section 5 that forms an image on the sheets S transported by the paper feed section 3.

The device body 2 is formed in a substantially rectangular parallelepiped shape and houses the paper feed unit 3 and the image forming unit 5. An opening 2A is formed on the top surface of the device body 2, and the device body 2 has a top cover 23 that can open and close the opening 2A.

The top cover 23 is configured to be rotatable around a pivot 23a at the rear end, and by rotating around the pivot 23a, it can move between a closed position in which the opening 2A is closed and an open position in which the opening 2A is opened. The top cover 23 of the device body 2 is formed with a paper discharge tray 23b that slopes downward from the front to the rear.

The paper feed unit 3 is disposed at the bottom of the device body 2, and conveys the sheet S supported on the paper feed tray 10 to the image forming unit 5 by the sheet conveying unit 30. The paper feed tray 10 is configured to be slidable in the front-rear direction, and is configured to be movable between a storage position where it is stored in the device body 2, and a separation position where it is pulled forward from the storage position.

The sheet transport section 30 includes a paper feed roller 32, a separation roller 33, a separation pad 33a, a pair of transport rollers 34, and a pair of registration rollers 35. Within the device body 2, a transport path P for the sheet S is configured, which runs from the paper feed tray 10 through the image forming section 5 to the paper discharge tray 23b.

The sheets S supported by the paper feed tray 10 are separated one by one by the paper feed roller 32, separation roller 33, and separation pad 33a and sent to the transport path P. The paper feed roller 32 is a roller that transports the sheets S from the paper feed tray 10 toward the image forming unit 5. The separation roller 33 and separation pad 33a constitute a separation means that separates the sheets S supported by the paper feed tray 10 one by one.

The sheet S sent to the transport path P is transported toward the image forming unit 5 by a transport roller pair 34 and a registration roller pair 35. The registration roller pair 35 regulates the movement of the leading edge of the transported sheet S, temporarily stops the sheet S, and then transports the sheet S toward the image forming unit 5 at a predetermined timing.

The image forming unit 5 is disposed above the paper feed unit 3, and includes four process cartridges 50 arranged side by side in the front-to-rear direction. Each process cartridge 50 corresponds to one of the colors: black, yellow, magenta, and cyan. The process cartridges 50 are removably mounted in the device main body 2. Each process cartridge 50 includes a photosensitive drum 51, a developing roller 52, a supply roller 53, a charger 54, and a drum cleaning roller 55.

The photosensitive drum 51 is formed in a generally cylindrical shape with its axis in the left-right direction, and is rotatably supported by the process cartridge 50. The developing roller 52 extends in the left-right direction, and is rotatably supported by the process cartridge 50. The supply roller 53 supplies the toner contained in the process cartridge 50 to the developing roller 52. The toner is an example of a developer. The developing roller 52 supplies the toner to the photosensitive drum 51.

The device main body 2 has an exposure head 59 that exposes the surface of the photosensitive drum 51. The exposure head 59 is supported by the top cover 23. Four exposure heads 59 are provided corresponding to the respective photosensitive drums 51, and the exposure heads 59 are arranged side by side in the front-to-rear direction.

The exposure head 59 extends downward from the top cover 23 and has an exposure section 59a at its lower end. The exposure section 59a is disposed adjacent to and above the photosensitive drum 51 when the top cover 23 is closed. The exposure section 59a is composed of an LED array with multiple LED elements arranged in parallel in the left-right direction.

The transfer belt 41 is disposed below the photosensitive drum 51 across the transport path P. The transfer belt 41 is in contact with the photosensitive drum 51. The transfer belt 41 is stretched between a drive roller 42 and a driven roller 43 disposed in front of the drive roller 42. A transfer roller 44 is disposed at a position facing each photosensitive drum 51 across the transfer belt 41. In the image forming unit 5, the transfer belt 41, the drive roller 42, the driven roller 43, the transfer roller 44, etc. constitute a belt device 40.

In the image forming unit 5, the photosensitive drums 51, which are uniformly charged by the chargers 54, are selectively exposed to light by the exposure heads 59. This exposure selectively removes charge from the surfaces of the photosensitive drums 51, and an electrostatic latent image is formed on the surfaces of the photosensitive drums 51.

The toner contained in the process cartridge 50 is positively charged between the supply roller 53 and the developing roller 52, and is carried on the surface of the developing roller 52. A developing bias is applied to the developing roller 52, and when the electrostatic latent image formed on the photosensitive drum 51 faces the developing roller 52, the potential difference between the electrostatic latent image and the developing roller 52 causes toner to be supplied from the developing roller 52 to the electrostatic latent image. As a result, a toner image is formed on the surface of the photosensitive drum 51.

When the sheet S transported toward the image forming unit 5 reaches the transfer belt 41, it is transported by the transfer belt 41 and passes between the transfer belt 41 and each photosensitive drum 51 in sequence. Then, when the toner image carried on the surface of the photosensitive drum 51 faces the sheet S, it is transferred to the sheet S by the transfer bias applied to the transfer roller 44.

At this time, toner that has not been transferred to the sheet S may remain on the surface of the photosensitive drum 51. The waste toner remaining on the surface of the photosensitive drum 51 faces the drum cleaning roller 55 as the photosensitive drum 51 rotates. The waste toner facing the drum cleaning roller 55 is electrically held on the surface of the drum cleaning roller 55 by the drum cleaning bias.

In this embodiment, the transfer belt 41 is configured as a conveyor belt that conveys the sheet S onto which the toner image is transferred, but it can also be configured as an intermediate transfer belt in which the toner image is transferred onto the belt itself, and the toner image transferred onto the belt is then transferred onto the sheet S.

The sheet S onto which the toner image has been transferred is transported to the fixing device 60. The fixing device 60 is equipped with a heating roller 61 and a pressure roller 62 that is in pressure contact with the heating roller 61. The toner image on the sheet S transported to the fixing device 60 is thermally fixed while passing between the heating roller 61 and the pressure roller 62.

The sheet S with the thermally fixed toner image is transported downstream in the transport direction from the fixing device 60, and is further transported by the intermediate discharge roller pair 63 and the discharge roller pair 64 arranged downstream in the transport direction of the intermediate discharge roller pair 63, and is discharged onto the discharge tray 23b.

Below the transfer belt 41 in the device main body 2 and above the paper feed tray 10, a cleaning unit 7 is provided to collect and store toner adhering to the transfer belt 41. The cleaning unit 7 is removably attached to the device main body 2.

The cleaning unit 7 has a frame 70, a belt cleaning roller 71, a collection roller 72, and a scraping blade 73. The belt cleaning roller 71 and the collection roller 72 are each rotatably supported by the frame 70.

The belt cleaning roller 71 is disposed below the transfer belt 41 in a position facing the backup roller 45 disposed within the transfer belt 41. The backup roller 45 is disposed within the transfer belt 41 so as to contact the transfer belt 41 from above.

The recovery roller 72 contacts the belt cleaning roller 71 from behind. The scraping blade 73 is supported by the frame 70 and is positioned below and behind the recovery roller 72. The front end of the scraping blade 73 contacts the surface of the recovery roller 72. Inside the frame 70, a storage chamber 74 is formed to store the recovered waste toner.

[Waste Toner Cleaning Operation]
In the image forming apparatus 1, when image formation by the image forming section 5 is completed, a cleaning operation is performed in which the waste toner held by the drum cleaning roller 55 is collected by the cleaning unit 7 and stored in the storage chamber 74.

In the cleaning operation, first, the waste toner held by the drum cleaning roller 55 is discharged onto the surface of the photosensitive drum 51, and the photosensitive drum 51 is rotated. The waste toner discharged onto the surface of the photosensitive drum 51 faces the transfer belt 41 as the photosensitive drum 51 rotates.

The waste toner on the surface of the photosensitive drum 51 facing the transfer belt 41 is transferred to the surface of the transfer belt 41 by the transfer bias of the transfer roller 44. The waste toner transferred to the surface of the transfer belt 41 is then transported to a position facing the belt cleaning roller 71 as the transfer belt 41 rotates.

The waste toner facing the belt cleaning roller 71 is electrostatically held on the surface of the belt cleaning roller 71 by the belt cleaning bias applied to the belt cleaning roller 71. In other words, the belt cleaning roller 71 removes the toner adhering to the transfer belt 41.

The belt cleaning roller 71 is an example of a cleaning roller that removes developer adhering to an object to be cleaned. The belt cleaning roller 71, which is made up of a roller member, is capable of easily and continuously removing toner adhering to the transfer belt 41. The transfer belt 41 is an example of an object to be cleaned. The object to be cleaned from which developer is removed by the cleaning roller is not limited to the transfer belt 41, and the photosensitive drum 51, etc. can also be used as the object to be cleaned by the cleaning roller.

The toner held by the belt cleaning roller 71 is electrostatically transferred to the recovery roller 72. The waste toner transferred to the recovery roller 72 is scraped off by the scraping blade 73, falls, and is stored in the storage chamber 74.

[Cleaning unit]
2 and 3, the belt cleaning roller 71 of the cleaning unit 7 extends along an axis X. The belt cleaning roller 71 is a roller member that rotates about the axis X. The belt cleaning roller 71 is an example of a cleaning roller. The belt cleaning roller 71 has one end 71A and the other end 71B in the direction of the axis X. The axis X is an axis that extends in the left-right direction.

The frame 70 has a first side wall 70A facing left and right at its right end, which is one end on the axis X, and a second side wall 70B facing left and right at its left end, which is the other end on the axis X. The first side wall 70A is an example of a side wall located at one end in the axial direction of the frame. One end 71A of the belt cleaning roller 71 is supported by the first side wall 70A of the frame 70, and the other end 71B of the belt cleaning roller 71 is supported by the second side wall 70B of the frame 70.

The belt cleaning roller 71 is equipped with a metal shaft 711 that extends along the axis X direction, and a roller body 712 that is formed into a cylindrical shape from a conductive resin member and covers the shaft 711. The roller body 712 comes into contact with the transfer belt 41 to remove toner that has adhered to the transfer belt 41.

The recovery roller 72 is formed of a generally cylindrical metal member extending in the left-right direction and is in pressure contact with the roller body 712 of the belt cleaning roller 71. The recovery roller 72 has one end 72A and the other end 72B in the direction of the axis X.

The scraping blade 73 is formed of a flat plate-shaped member with its longitudinal direction in the left-right direction, and is pressed against the recovery roller 72. The scraping blade 73 scrapes off and recovers the toner adhering to the recovery roller 72. In the cleaning unit 7, the toner adhering to the transfer belt 41 is removed by the belt cleaning roller 71, the recovery roller 72, and the scraping blade 73, and is stored in the storage chamber 74.

The upper side of the storage chamber 74 is closed by the upper surface 70D of the frame 70. The cleaning unit 7 is equipped with a transport member 75 located inside the storage chamber 74. The transport member 75 is a member that transports the toner contained in the storage chamber 74 rearward.

[Frame-based support structure for belt cleaning roller and collection roller]
4 and 5, the shaft 711 has a bearing portion 711a, a conductive support portion 711b, and an engagement portion 711c at one end portion 71A of the belt cleaning roller 71. The bearing portion 711a of the shaft 711 is supported by a first side wall 70A of the frame 70. The conductive support portion 711b of the shaft 711 is located to the right of the bearing portion 711a and protrudes rightward beyond the first side wall 70A of the frame 70.

The cleaning unit 7 includes a bearing 80 that rotatably supports the bearing portion 711a located at one end 71A of the belt cleaning roller 71 on the first side wall 70A of the frame 70. The first side wall 70A of the frame 70 has a support hole 701, and the bearing 80 is fitted into the support hole 701 so as to be movable in the left-right direction.

As shown in Figures 5 and 6, the bearing 80 has a cylindrical rib 801, a first rib 802, and a third rib 803.

The cylindrical rib 801 is formed in a cylindrical shape extending in the left-right direction and is fitted into the support hole 701 of the first side wall 70A. The cylindrical rib 801 rotatably supports the bearing portion 711a of the shaft 711. In other words, the shaft 711 is supported by the first side wall 70A of the frame 70 via the bearing 80.

The first rib 802 is located at the right end of the cylindrical rib 801. The first rib 802 is formed of a plate-like member extending from the right end of the cylindrical rib 801 toward the outer diameter side. The first rib 802 is located to the right of the first side wall 70A. The right side is an example of one side in the axial direction. The first rib 802 extends toward the outer diameter side beyond the periphery of the support hole 701, and can engage with the first side wall 70A from the right. By engaging the first rib 802 with the first side wall 70A, it is possible to prevent the bearing 80 from slipping out of the support hole 701 to the left.

The third rib 803 is located at the left end of the cylindrical rib 801. The third rib 803 is a protrusion extending from the left end of the cylindrical rib 801 toward the outer diameter side. The third rib 803 is located to the left of the first side wall 70A. The left side is an example of the other side in the axial direction. The third rib 803 extends toward the outer diameter side beyond the periphery of the support hole 701, and can engage with the first side wall 70A from the left. By engaging the third rib 803 with the first side wall 70A, it is possible to prevent the bearing 80 from slipping out of the support hole 701 to the right.

The cylindrical rib 801 of the bearing 80 has a protruding portion 801a that protrudes leftward from the first side wall 70A when the first rib 802 and the first side wall 70A are in contact with each other. The protruding portion 801a is a part of the cylindrical rib 801. The third rib 803 is fixed to the protruding portion 801a of the cylindrical rib 801.

The cleaning unit 7 includes a conductive bearing 81 attached to one end 71A of the belt cleaning roller 71. The conductive bearing 81 is attached to the conductive support portion 711b of the shaft 711 located at one end 71A of the belt cleaning roller 71. The conductive support portion 711b is located to the right of the bearing portion 711a, and the conductive bearing 81 is attached to the belt cleaning roller 71 to the right of the bearing 80 fitted into the bearing portion 711a.

As shown in Figures 5 and 7, the conductive bearing 81 is made of a conductive material such as a conductive resin, and is formed into a cylindrical shape extending in the left-right direction. The conductive bearing 81 has a plurality of ribs 811 extending in the radial direction on the right side surface. The ribs 811 are visible when the conductive bearing 81 is viewed from the right.

Therefore, when the conductive bearing 81 is attached to the conductive support portion 711b of the shaft 711, the rib 811 can be seen from the right, making it easy to confirm that the conductive bearing 81 is attached in the correct orientation.

The conductive bearing 81 has a protrusion 812 that protrudes radially inward from the left end of the inner circumferential surface. The protrusion 812 can engage with the engagement portion 711c of the shaft 711. As shown in FIG. 7(c), when the conductive bearing 81 is fitted to the conductive support portion 711b of the shaft 711, the protrusion 812 and the engagement portion 711c engage with each other. This makes it possible to prevent the conductive bearing 81 fitted to the conductive support portion 711b from coming off the shaft 711.

As shown in Figures 4 and 5, one end 72A of the recovery roller 72 in the axial direction X is supported by a first side wall 70A of the frame 70, and the other end 72B of the recovery roller 72 in the axial direction X is supported by a second side wall 70B of the frame 70. The recovery roller 72 has a bearing portion 72a located at the one end 72A, a conductive support portion 72b, and an engagement portion 72c.

The bearing portion 72a of the recovery roller 72 is supported by the first side wall 70A. The conductive support portion 72b of the recovery roller 72 protrudes to the right beyond the first side wall 70A of the frame 70.

The cleaning unit 7 includes a bearing 82 that rotatably supports the bearing portion 72a located at one end 72A of the collection roller 72 on the first side wall 70A of the frame 70. The first side wall 70A of the frame 70 has a support hole 702, and the bearing 82 is fitted into the support hole 702 so as to be movable in the left-right direction.

Bearing 82 is formed similarly to bearing 80 and has a cylindrical rib 821, a first rib 822, and a third rib 823.

The cylindrical rib 821 is formed in a cylindrical shape extending in the left-right direction and is fitted into the support hole 701 of the first side wall 70A. The cylindrical rib 821 rotatably supports the bearing portion 72a of the collection roller 72. In other words, the collection roller 72 is supported by the first side wall 70A of the frame 70 via the bearing 82.

The first rib 822 is located at the right end of the cylindrical rib 821 and extends from the right end of the cylindrical rib 821 toward the outer diameter side. The first rib 822 is located to the right of the first side wall 70A. The first rib 822 can engage with the first side wall 70A from the right. The engagement of the first rib 822 with the first side wall 70A can prevent the bearing 82 from slipping out of the support hole 702 to the left.

The third rib 823 is located at the left end of the cylindrical rib 821 and extends from the left end of the cylindrical rib 821 toward the outer diameter side. The third rib 823 is located to the left of the first side wall 70A. The third rib 823 can engage with the first side wall 70A from the left. By engaging the third rib 823 with the first side wall 70A, it is possible to prevent the bearing 82 from slipping out of the support hole 702 to the right.

The cylindrical rib 821 of the bearing 82 has a protrusion 821a that protrudes leftward from the first side wall 70A when the first rib 822 and the first side wall 70A are in contact with each other. The protrusion 821a is a part of the cylindrical rib 821. The third rib 823 is fixed to the protrusion 821a of the cylindrical rib 821.

The cleaning unit 7 includes a conductive bearing 83 attached to one end 72A of the collection roller 72. The conductive bearing 83 is attached to a conductive support portion 72b located at one end 72A of the collection roller 72. The conductive support portion 72b is located to the right of the bearing portion 72a, and the conductive bearing 83 is attached to the collection roller 72 to the right of the bearing 82 fitted into the bearing portion 72a.

The conductive bearing 83 is configured similarly to the conductive bearing 81, and has multiple ribs 831 extending radially on the right side surface. The ribs 831 can be seen when the conductive bearing 83 is viewed from the right.

The conductive bearing 83 has a protruding portion 832 that protrudes radially inward from the left end of the inner circumferential surface. The protruding portion 832 can engage with the engaging portion 72c of the recovery roller 72. When the conductive bearing 83 is fitted to the conductive support portion 72b of the recovery roller 72, the protruding portion 832 engages with the engaging portion 72c. This makes it possible to prevent the conductive bearing 83 fitted to the conductive support portion 72b from coming out of the recovery roller 72.

[electrode]
4, the cleaning unit 7 includes an electrode 85 supported by a first side wall 70A of the frame 70. The electrode 85 includes a first electrode 851, a second electrode 852, and a third electrode 853.

The first electrode 851 is made of a bent metal plate and has a main body 851a and an external contact 851b. The main body 851a is supported on the right side of the first side wall 70A. The external contact 851b is formed continuously below the main body 851a on the right side of the first side wall 70A. The first electrode 851 is electrically connected to a detector that detects when the cleaning unit 7 is full of waste toner. The first electrode 851 is supported on one side wall of the frame and is an example of an electrode that is electrically connected to the cleaning unit.

The second electrode 852 is made of a bent metal plate and has a main body portion 852a, an external contact portion 852b, and a contact portion 852c. The main body portion 852a is supported on the right side surface of the first side wall 70A. The external contact portion 852b is formed continuously below the main body portion 852a on the right side surface of the first side wall 70A. The main body portion 852a is located behind the main body portion 851a of the first electrode 851, and the external contact portion 852b is located behind the external contact portion 851b of the first electrode 851.

The contact portion 852c extends obliquely upward from the main body portion 852a and contacts the outer circumferential surface of the conductive bearing 81. Since the conductive bearing 81 is made of a conductive material, the contact portion 852c contacts the conductive bearing 81, electrically connecting the second electrode 852 and the shaft 711 of the belt cleaning roller 71.

The third electrode 853 is made of a bent metal plate and has a main body portion 853a, an external contact portion 853b, and a contact portion 853c. The main body portion 853a is supported on the right side surface of the first side wall 70A. The external contact portion 853b is formed continuously below the main body portion 853a on the right side surface of the first side wall 70A. The main body portion 853a is located behind the main body portion 852a of the second electrode 852, and the external contact portion 853b is located behind the external contact portion 852b of the second electrode 852.

The contact portion 853c extends obliquely upward from the main body portion 853a and contacts the outer peripheral surface of the conductive bearing 83. Since the conductive bearing 83 is made of a conductive material, the contact portion 853c contacts the conductive bearing 83, electrically connecting the third electrode 853 and the collection roller 72.

The first electrode 851 is configured to be grounded when the cleaning unit 7 is attached to the device body 2. In addition, when the cleaning unit 7 is attached to the device body 2, a belt cleaning bias is applied to the second electrode 852, and a power supply voltage is applied to the third electrode 853.

[cover]
4 and 5, the cleaning unit 7 includes a cover 90 that covers the right side of the first side wall 70A of the frame 70. The cover 90 is attached to the right side surface of the first side wall 70A, and the cover 90 covers the bearing 80, the conductive bearing 81, the bearing 82, the conductive bearing 83, the main body 851a of the first electrode 851, the main body 852a and the contact portion 852c of the second electrode 852, and the main body 853a and the contact portion 853c of the third electrode 853, etc., from the right side.

As shown in Figures 4, 5, and 8, the cover 90 has a cover plate 901, a second rib 902, a fourth rib 903, a first pressing rib 904, a second pressing rib 906, and a third pressing rib 906.

The cover plate 901 is a plate-shaped member that faces in the left-right direction, and covers the bearing 80, the conductive bearing 81, the bearing 82, the conductive bearing 83, the main body 851a of the first electrode 851, the main body 852a and the contact portion 852c of the second electrode 852, and the main body 853a and the contact portion 853c of the third electrode 853 from the right side.

The second rib 902 protrudes leftward from the cover plate 901 and is formed in an arc shape. The second rib 902 is disposed so as to surround the outer periphery of the conductive bearing 81, and is positioned so as to overlap the first rib 802 of the bearing 80 when projected in the direction of the axis X, and is configured to be able to abut against the first rib 802.

The second rib 902 is arranged to avoid the location on the outer periphery of the conductive bearing 81 where the contact portion 852c of the second electrode 852 contacts the conductive bearing 81, and therefore does not interfere with the second electrode 852. In addition, the second rib 902, which is formed in an arc shape, is arranged on a portion of the outer periphery of the conductive bearing 81, rather than the entire circumference, which allows for greater freedom when placing components on the outer periphery of the conductive bearing 81.

The second rib 902 is positioned with a gap between it and the first rib 802 of the bearing 80 in the direction of the axis X. As shown in FIG. 9, when the first side wall 70A of the frame 70 and the first rib 802 of the bearing 80 are in contact with each other in the direction of the axis X, the first rib 802 and the second rib 902 are positioned with a first gap G1 between them.

In addition, in the direction of axis X, when the first side wall 70A of the frame 70 and the first rib 802 of the bearing 80 are in contact with each other, the third rib 803 of the bearing 80 and the first side wall 70A of the frame 70 are positioned with a second gap G2 between them. The first gap G1 is set to be larger than the second gap G2.

Here, the bearing 80 is fitted in the support hole 701 in the first side wall 70A so as to be movable in the left-right direction, and when the belt cleaning roller 71 moves in the left-right direction, the bearing 80 may also move in the left-right direction in conjunction with the movement of the belt cleaning roller 71.

For example, when the bearing 80 moves to the right from a state in which the first side wall 70A and the first rib 802 are in contact, the third rib 803 of the bearing 80 comes into contact with the first side wall 70A. If a load to the right acts on the bearing 80 after the third rib 803 comes into contact with the first side wall 70A, the bearing 80 moves further to the right as the third rib 803 elastically deforms.

When the bearing 80 moves further to the right after the third rib 803 abuts against the first side wall 70A, the first rib 802 abuts against the second rib 902, restricting the rightward movement of the bearing 80. In other words, the abutment between the first rib 802 and the second rib 902 makes it possible for the cover 90 to support the rightward load applied to the bearing 80.

Therefore, when the cleaning unit 7 is dropped while packaged and the belt cleaning roller 71 moves in the direction of the axis X, the first rib 802 and the second rib 902 come into contact with each other, and the load on the bearing 80 in the direction of the axis X can be supported by the cover 90. This prevents the third rib 803 of the bearing 80 from being damaged by an excessive load, and makes it possible to maintain proper support of the bearing 80 by the first side wall 70A of the frame 70.

In particular, because the first gap G1 is set larger than the second gap G2, the first rib 802 and the second rib 902 do not come into contact with each other during normal use of the cleaning unit 7, and the smooth rotation of the belt cleaning roller 71 is not impeded. On the other hand, when a load is applied to the cleaning unit 7 in a direction that moves the belt cleaning roller 71 to the right, the load acting on the third rib 803 in the direction of the axis X is reduced, preventing the third rib 803 from being damaged, and the first side wall 70A of the frame 70 can maintain proper support of the bearing 80.

In this embodiment, the first gap G1 is set to 0.1 mm or more and 1.0 mm or less. By setting the first gap G1 in this manner, when a load in the direction of the axis X is applied to the bearing 80, it is possible to prevent the bearing 80 from moving significantly to the right and damaging the third rib 803, and to maintain proper support of the bearing 80 by the first side wall 70A of the frame 70.

The first gap G1 is preferably set to 0.4 mm or more and 0.6 mm or less. By setting the first gap G1 in this manner, when a load is applied to the bearing 80 in the direction of the axis X, the bearing 80 is prevented from moving significantly to the right and damaging the third rib 803, and the first side wall 70A of the frame 70 can maintain proper support for the bearing 80.

As shown in FIG. 9, the protrusion 801a of the cylindrical rib 801 of the bearing 80 protrudes to the left from the first side wall 70A by a length L when the first rib 802 and the first side wall 70A are in contact with each other. The first distance G1 between the first rib 802 and the second rib 902 is set to be equal to or less than the length L of the protrusion 801a.

In this way, by making the first interval G1 equal to or less than the length L of the protrusion 801a, when a load in the axial direction is applied to the bearing 80 and the bearing 80 moves to the right, even if the third rib 803 abutting the first side wall 70A is damaged, the cylindrical rib 801 of the bearing 80 can be prevented from slipping out of the support hole 701 of the first side wall 70A. This makes it possible to maintain proper support of the bearing 80 by the first side wall 70A of the frame 70.

In addition, since the protrusion 801a is a positional portion of the cylindrical rib 801, even if the bearing 80 moves in the direction of the axis X, it is possible to maintain proper support of the bearing 80 by the first side wall 70A of the frame 70.

The fourth rib 903 protrudes leftward from the cover plate 901 and is formed in an arc shape. The fourth rib 903 is disposed so as to surround the outer periphery of the conductive bearing 83, and is positioned so as to overlap the first rib 822 of the bearing 82 when projected in the direction of the axis X, and is configured to be able to abut against the first rib 822.

The fourth rib 903 is arranged to avoid the location on the outer periphery of the conductive bearing 83 where the contact portion 853c of the third electrode 853 contacts the conductive bearing 83, and therefore does not interfere with the third electrode 853. In addition, the fourth rib 903, which is formed in an arc shape, is arranged on a portion of the outer periphery of the conductive bearing 83, rather than the entire circumference, which allows for greater freedom when placing components on the outer periphery of the conductive bearing 83.

The fourth rib 903 is positioned with a gap between it and the first rib 822 in the axial direction when the first side wall 70A of the frame 70 is in contact with the first rib 822 of the bearing 82. In addition, in the axial direction when the first side wall 70A is in contact with the first rib 802, the third rib 823 of the bearing 82 is positioned with a gap between it and the first side wall 70A. The gap between the fourth rib 903 and the first rib 822 is set larger than the gap between the third rib 823 and the first side wall 70A.

Therefore, when the cleaning unit 7 is dropped while packaged and the collection roller 72 moves in the direction of the axis X, the first rib 822 and the fourth rib 903 come into contact with each other, allowing the load on the bearing 82 in the direction of the axis X to be supported by the cover 90. This prevents the third rib 823 of the bearing 82 from being damaged by an excessive load, and allows the first side wall 70A of the frame 70 to properly support the bearing 82.

In this embodiment, the gap between the fourth rib 903 and the first rib 822 is set to 0.1 mm or more and 1.0 mm or less. It is also preferable that the gap between the fourth rib 903 and the first rib 822 is set to 0.4 mm or more and 0.6 mm or less. Furthermore, the gap between the fourth rib 903 and the first rib 822 is set to be equal to or less than the length in the axial direction X of the protruding portion 821a of the cylindrical rib 821 of the bearing 82.

Furthermore, in the cleaning unit 7, the first gap G1 and the second gap G2 can be set so that the second gap G2 is larger than the first gap G1.

In this case, when the collection roller 72 moves to the right, the second rib 902 of the cover 90 abuts against the first rib 822 of the bearing 80 before the third rib 823 engages with the first side wall 70A of the frame 70, and the load in the axial direction of the X axis applied to the bearing 80 can be supported by the cover 90. This prevents the load in the axial direction of the X axis from acting on the third rib 823 and causing damage, and ensures that the first side wall 70A of the frame 70 properly supports the bearing 80.

As shown in Figures 4 and 8, the first pressing rib 904 protrudes leftward from the cover plate 901. When projected in the direction of axis X, the first pressing rib 904 is located at a position overlapping the main body portion 851a of the first electrode 851, and abuts against the main body portion 851a of the first electrode 851 to press the first electrode 851 from the right side. By the first pressing rib 904 pressing the first electrode 851, it is possible to prevent the first electrode 851 supported by the first side wall 70A from falling off the first side wall 70A.

The first pressing rib 904 is located below the second rib 902 and is connected to the lower end of the second rib 902. In other words, the first pressing rib 904 is formed continuously with the second rib 902. By forming the first pressing rib 904 and the second rib 902 continuously, it is possible to improve the strength of the first pressing rib 904 and the second rib 902. The first pressing rib 904 is an example of a pressing rib formed continuously with the second rib.

The second pressing rib 905 protrudes to the left from the cover plate 901. When projected in the direction of the axis X, the second pressing rib 905 is located at a position overlapping with the main body portion 852a of the second electrode 852, and abuts against the main body portion 852a of the second electrode 852 to press the second electrode 852 from the right side. By the second pressing rib 905 pressing the second electrode 852, it is possible to prevent the second electrode 852 supported by the first side wall 70A from falling off the first side wall 70A.

The second pressing rib 905 is located below the fourth rib 903 and is connected to the lower end of the fourth rib 903. In other words, the second pressing rib 905 is formed continuously with the fourth rib 903. By forming the second pressing rib 905 and the fourth rib 903 continuously, it is possible to improve the strength of the second pressing rib 905 and the fourth rib 903.

The third pressing rib 906 protrudes to the left from the cover plate 901. When projected in the direction of the axis X, the third pressing rib 906 is located at a position overlapping with the main body portion 853a of the third electrode 853, and abuts against the main body portion 853a of the third electrode 853 to press the third electrode 853 from the right side. By the third pressing rib 906 pressing the third electrode 853, it is possible to prevent the third electrode 853 supported by the first side wall 70A from falling off the first side wall 70A.

As shown in Figures 5, 8, and 9, the cover plate 901 of the cover 90 has a circular escape groove 911 recessed to the right at a position facing the conductive bearing 81 in the axial X direction. The cover plate 901 of the cover 90 also has a circular escape hole 912 penetrating in the axial X direction at a position facing the shaft 711 of the belt cleaning roller 71 in the axial X direction. The escape hole 912 is located at the bottom of the escape groove 911, and the escape hole 912 and the escape groove 911 are arranged concentrically.

The diameter D1 of the escape groove 911 is larger than the diameter D3 of the conductive bearing 81, and the diameter D2 of the escape hole 912 is larger than the diameter D4 of the conductive support part 711b located at the right end of the shaft 711 and smaller than the diameter D3 of the conductive bearing 81.

In this way, the escape groove 911 is formed at a position of the cover 90 facing the conductive bearing 81. Therefore, when the conductive bearing 81 attached to the conductive support portion 711b of the shaft 711 moves to the right together with the shaft 711, the conductive bearing 81 can be accommodated in the escape groove 911, and interference between the conductive bearing 81 and the cover 90 can be prevented.

In addition, a relief hole 912 is formed in the position of the cover 90 facing the shaft 711. When the shaft 711 moves to the right, the conductive support portion 711b of the shaft 711 can protrude to the right side of the cover 90 through the relief hole 912, preventing interference between the shaft 711 and the cover 90.

In this case, the diameter D2 of the escape hole 912 is smaller than the diameter D3 of the conductive bearing 81, so that the conductive bearing 81 housed in the escape groove 911 can be prevented from passing through the escape hole 912 and popping out to the right side of the cover 90.

As shown in Figures 5 and 8, the cover plate 901 of the cover 90 has a circular escape groove 921 recessed to the right at a position facing the conductive bearing 83 in the axial X direction. The cover plate 901 of the cover 90 also has a circular escape hole 922 penetrating in the axial X direction at a position facing the recovery roller 72. The escape hole 922 is located at the bottom of the escape groove 921, and the escape hole 922 and the escape groove 921 are arranged concentrically.

The diameter of the escape groove 921 is larger than the diameter of the conductive bearing 83, and the diameter of the escape hole 922 is larger than the diameter of the conductive support portion 72b of the recovery roller 72 and smaller than the diameter of the conductive bearing 83.

As a result, when the conductive bearing 83 moves to the right together with the collection roller 72, the conductive bearing 83 can be accommodated in the escape groove 921, and interference between the conductive bearing 83 and the cover 90 can be suppressed. Also, when the collection roller 72 moves to the right, the conductive support portion 72b of the collection roller 72 can protrude to the right side of the cover 90 through the escape hole 922, and interference between the collection roller 72 and the cover 90 can be suppressed. Furthermore, it is possible to suppress the conductive bearing 83 accommodated in the escape groove 921 from passing through the escape hole 922 and protruding to the right side of the cover 90.

As shown in Figures 2, 5, and 9, the cover plate 901 of the cover 90 has a contact surface 901a facing to the right. The contact surface 901a is the surface that comes into contact with the packaging material PM when the cleaning unit 7 is packed, and is located at a position where the second rib 902 and the fourth rib 903 of the cover 90 are projected in the direction of the axis X.

In this way, the cover 90 has a contact surface 901a that comes into contact with the packaging material PM for packaging the cleaning unit 7, so that when a load is applied to the cover 90, the load applied to the cover 90 can be supported by the packaging material FM via the contact surface 901a.

In particular, since the contact surface 901a is located at a position where the second rib 902 is projected in the direction of the axis X, when the belt cleaning roller 71 moves in the direction of the axis X, the load from the belt cleaning roller 71 can be effectively supported by the packaging material PM via the bearing 80, the second rib 902 of the cover 90, and the contact surface 901a of the cover 90.

In this case, the rotating belt cleaning roller 71 does not come into direct contact with the cover 90, so the rotation of the belt cleaning roller 71 is not impeded. In addition, the second rib 902 is arranged to surround the outer periphery of the conductive bearing 81, so it can come into contact with a position close to the center of the bearing 80, making it possible to effectively support the load from the belt cleaning roller 71.

In addition, since the contact surface 901a is located at a position where the fourth rib 903 is projected in the direction of the axis X, when the recovery roller 72 moves in the direction of the axis X, the load from the recovery roller 72 can be effectively supported by the packaging material PM via the bearing 82, the fourth rib 903 of the cover 90, and the contact surface 901a of the cover 90.

In this case, the rotating collection roller 72 does not come into direct contact with the cover 90, so the rotation of the collection roller 72 is not impeded. In addition, the fourth rib 903 is arranged to surround the outer periphery of the conductive bearing 83, so it can come into contact with a position close to the center of the bearing 82, making it possible to effectively support the load from the collection roller 72.

1 Image forming apparatus 7 Cleaning unit 41 Transfer belt 70 Frame 70A First side wall 71 Belt cleaning roller 71A One end 71B Other end 80 Bearing 81 Conductive bearing 85 Electrode 90 Cover 711 Shaft 711a Bearing portion 711b Conductive support portion 801 Cylindrical rib 801a Protrusion 802 First rib 803 Third rib 811 Rib 851 First electrode 901 Cover plate 901a Contact surface 902 Second rib 904 First pressing rib 911 Relief groove 912 Relief hole D1 Diameter (of relief groove) D2 Diameter (of relief hole) D3 Diameter (of conductive bearing) D4 Diameter (of conductive support portion on shaft) G1 First interval G2 Second interval L Length (of protrusion) PM Packaging material X axis

Claims (15)

a cleaning roller that removes developer adhering to a cleaning target, extends along an axis, and has one end and another end in the axial direction;
a frame supporting the cleaning roller and including a side wall located at one end side in the axial direction;
a bearing that rotatably supports the one end of the cleaning roller on the one side wall, the bearing having a first rib located on one side of the one side wall of the frame in the axial direction, and a third rib located on the other side of the one side wall of the frame in the axial direction and engageable with the one side wall;
a cover that covers the bearing from one side in the axial direction,
The cleaning unit includes a cover that is positioned so as to overlap the first rib when projected in the axial direction and that includes a second rib that is capable of abutting against the first rib. In the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first interval therebetween, and the one side wall of the frame and the third rib are positioned with a second interval therebetween,
The cleaning unit of claim 1 , wherein the first spacing is greater than the second spacing. The cleaning unit according to claim 2, wherein the first gap is 0.1 mm or more and 1.0 mm or less. The cleaning unit according to claim 3, wherein the first gap is 0.4 mm or more and 0.6 mm or less. In the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first interval therebetween,
the bearing has a protruding portion that protrudes from the one side wall of the frame to the other side in the axial direction when the one side wall of the frame and the first rib are in contact with each other,
The cleaning unit according to claim 1 , wherein the first interval is equal to or less than a length of the protrusion in the axial direction. the bearing is formed in a cylindrical shape extending in the axial direction, and includes a cylindrical rib having one end in the axial direction on which the first rib is located and the other end in the axial direction on which the third rib is located,
The cleaning unit according to claim 5 , wherein the protrusion is a part of the cylindrical rib. In the axial direction, when the one side wall of the frame and the first rib are in contact with each other, the first rib and the second rib are positioned with a first interval therebetween, and the one side wall of the frame and the third rib are positioned with a second interval therebetween,
The cleaning unit according to claim 1 , wherein the second spacing is greater than the first spacing. a conductive bearing attached to the cleaning roller on one side of the bearing in the axial direction,
8. The cleaning unit according to claim 1, wherein the second rib has an arc shape and is disposed so as to surround an outer periphery of the conductive bearing. an electrode supported on the one side wall of the frame and electrically connected to the cleaning unit;
the cover has a pressing rib that presses the electrode from one side in the axial direction,
The cleaning unit according to any one of claims 1 to 7, wherein the pressing rib and the second rib are formed continuously. The cleaning unit according to claim 8, wherein the cover has an escape groove recessed to one side in the axial direction at a position facing the conductive bearing in the axial direction. The cleaning roller has a shaft extending along the axial direction,
The cleaning unit according to claim 10 , wherein the cover is provided with an escape hole penetrating in the axial direction at a position facing the shaft in the axial direction. The diameter of the relief groove is larger than the diameter of the conductive bearing,
12. The cleaning unit according to claim 11, wherein a diameter of the escape hole is larger than a diameter of one end of the shaft in the axial direction and smaller than a diameter of the conductive bearing. The cleaning unit according to any one of claims 1 to 7, wherein the cover has a contact surface that comes into contact with a packaging material for packaging the cleaning unit. The cleaning unit according to claim 13, wherein the contact surface is located at a position where the second rib on the cover is projected in the axial direction. The cleaning unit according to claim 8, wherein the conductive bearing has a plurality of ribs formed on one side in the axial direction and extending radially.

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