Cleaning device and image forming apparatus

A cleaning device includes a cleaning member that removes toner from a surface of an image holder by bringing an upper end portion into contact with the surface from a downstream side in a rotation direction of the image holder, a housing that supports the cleaning member and that stores the toner removed from the surface of the image holder by the cleaning member, and a transport member that is provided in the housing and that transports the toner stored in the housing to an outside of the housing at the same height as a contact portion of the cleaning member that comes into contact with the surface of the image holder or at a position above the contact portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2022-052253 filed Mar. 28, 2022.

BACKGROUND

(i) Technical Field

The present disclosure relates to a cleaning device and an image forming apparatus.

(ii) Related Art

Disclosed in JP2005-173351A is a cleaning device including a cleaning member that comes into contact with a surface of a cleaning target member and that relatively moves on the surface to remove an adhering substance, and a collection container that includes an opening facing the cleaning target member on a cleaning member upstream side so that the adhering substance removed by the cleaning member is collected in the vicinity of the cleaning member. In the collection container, a powder supply unit for supply of a powder onto the cleaning target member is provided.

SUMMARY

Meanwhile, in the case of a configuration in which toner different from toner removed from a surface of an image holder is supplied to, as a lubricant material, a contact portion of a cleaning member that comes into contact with the surface, the amount of toner to be used is increased.

Aspects of non-limiting embodiments of the present disclosure relate to a cleaning device and an image forming apparatus that reduce the amount of toner to be used and suppress poor cleaning of an image holder in comparison with a configuration in which toner different from toner removed from a surface of an image holder is supplied to, as a lubricant material, a contact portion of a cleaning member that comes into contact with the surface.

According to an aspect of the present disclosure, there is provided a cleaning device including a cleaning member that removes toner from a surface of an image holder by bringing an upper end portion into contact with the surface from a downstream side in a rotation direction of the image holder, a housing that supports the cleaning member and that stores the toner removed from the surface of the image holder by the cleaning member, and a transport member that is provided in the housing and that transports the toner stored in the housing to an outside of the housing at the same height as a contact portion of the cleaning member that comes into contact with the surface of the image holder or at a position above the contact portion.

DETAILED DESCRIPTION

Hereinafter, an image forming apparatus according to an exemplary embodiment will be described with reference to the drawings.

Overall Configuration of Image Forming Apparatus

FIG.1is a schematic configuration view showing an example of the configuration of the image forming apparatus according to the exemplary embodiment. As shown inFIG.1, an image forming apparatus40includes first to fourth electrophotographic image forming units10Y,10M,10C, and10K. The first to fourth image forming units10Y,10M,10C, and10K output images of respective colors, which are yellow (Y), magenta (M), cyan (C), and black (K), based on image data.

The plurality of image forming units10Y,10M,10C, and10K are arranged at predetermined intervals along an intermediate transfer belt20which will be described later. Each of the image forming units10Y,10M,10C, and10K is an example of an image forming unit.

InFIG.1, above the image forming units10Y,10M,10C, and10K, the intermediate transfer belt20that extends over the image forming units10Y,10M,10C, and10K and has an endless belt-like shape is disposed. The intermediate transfer belt20is wound around a drive roller22and a support roller24that are disposed to be separated from each other. In addition, the intermediate transfer belt20rotates in a direction from the first image forming unit10Y to the fourth image forming unit10K as shown by an arrow R.

A force is applied to the support roller24in a direction away from the drive roller22by a spring or the like (not shown), and a tension is applied to the intermediate transfer belt20supported by the drive roller22and the support roller24. In addition, a cleaning device60, which faces the drive roller22with the intermediate transfer belt20interposed therebetween, is provided outside the intermediate transfer belt20. The cleaning device60removes toner remaining on a surface20S (refer toFIG.2) of the intermediate transfer belt20. Note that the configuration of the cleaning device60will be described later.

Toner including toner of four colors (yellow, magenta, cyan, and black) contained in toner cartridges8Y,8M,8C, and8K is supplied to respective developing devices4Y,4M,4C, and4K of the image forming units10Y,10M,10C, and10K.

The first to fourth image forming units10Y,10M,10C, and10K have the same configuration as each other. Therefore, in the following description, the configuration of the first image forming unit10Y that is disposed on an upstream side in a rotation direction of the intermediate transfer belt20and that forms a yellow image will be described and the configurations of the second to fourth image forming units10M,10C, and10K will not be described.

Note that, regarding the second to fourth image forming units10M,10C, and10K, the same components as components of the first image forming unit10Y are given the same reference numerals as the components of the first image forming unit10Y. In addition, Y (yellow), M (magenta), C (cyan), or K (black) is added to the ends of reference numerals given to components of the first to fourth image forming units10Y,10M,10C, and10K.

The first image forming unit10Y has a photoreceptor1Y. In the vicinity of the photoreceptor1Y, in order from an upstream side in a rotation direction of the photoreceptor1Y, a charging roller2Y that charges a surface of the photoreceptor1Y to a predetermined potential, an exposure device3that causes the charged surface to be exposed to a laser beam3Y based on an image signal so as to form an electrostatic latent image, the developing device4Y that develops the electrostatic latent image with toner, a primary transfer roller5Y that transfers the developed toner image onto the intermediate transfer belt20, and a cleaning device6Y that removes toner remaining on the surface of the photoreceptor1Y after primary transfer are provided.

Note that the primary transfer roller5Y is disposed inside the intermediate transfer belt20and faces the photoreceptor1Y with the intermediate transfer belt20interposed therebetween. Further, a bias power supply (not shown) that applies a primary transfer bias is connected to the primary transfer roller5Y.

The image forming apparatus40is provided with an accommodation portion32that accommodates recording paper P which is an example of a recording medium. In addition, the image forming apparatus40is provided with a paper feeding roller34that feeds the recording paper P in the accommodation portion32and a plurality of transport rollers36that transport the recording paper P along a transport path38.

In addition, the image forming apparatus40is provided with a secondary transfer unit23. The secondary transfer unit23includes the intermediate transfer belt20, the support roller24that comes into contact with a rear surface of the intermediate transfer belt20, and a secondary transfer roller26disposed outside the intermediate transfer belt20. In the secondary transfer unit23, a toner image that is multilayer-transferred onto the surface20S of the intermediate transfer belt20is transferred onto the recording paper P in a case where a secondary transfer bias is applied to the support roller24.

The image forming apparatus40is provided with a fixation device28. The fixation device28includes a fixation member52and a pressing member54pressed against the fixation member52. In a case where the recording paper P passes through a nip portion where the fixation member52and the pressing member54come into pressure-contact with each other, a toner image that is multilayer-transferred onto the recording paper P is fixed to the recording paper P.

Action of Image Forming Apparatus

Next, an operation of forming a yellow image at the first image forming unit10Y will be described. A surface of the photoreceptor1Y is charged by the charging roller2Y. The surface of the photoreceptor1Y is irradiated with the laser beam3Y from the exposure device3. Accordingly, an electrostatic latent image is formed on the surface of the photoreceptor1Y.

The electrostatic latent image formed on the surface of the photoreceptor1Y is visualized as a toner image by the developing device4Y. The toner image developed on the photoreceptor1Y is transported to a predetermined primary transfer position. Then, a primary transfer bias is applied to the primary transfer roller5Y, so that the toner image formed on the surface of the photoreceptor1Y is transferred onto a surface of the intermediate transfer belt20. Thereafter, toner (residual toner) remaining on the surface of the photoreceptor1Y is removed and collected by the cleaning device6Y.

In addition, in the second to fourth image forming units10M,10C, and10K as well, toner images corresponding to respective colors are formed on surfaces of photoreceptors1M,1C, and1K through the same operation as in the first image forming unit10Y. The intermediate transfer belt20to which a yellow toner image has been transferred at the first image forming unit10Y is moved to the second to fourth image forming units10M,10C, and10K in order. Then, to the surface20S of the intermediate transfer belt20, the toner images of the respective colors that are formed on the surfaces of photoreceptors1M,1C, and1K are multilayer-transferred in a superimposing manner by primary transfer rollers5M,5C, and5K.

The intermediate transfer belt20with the surface onto which the four-color toner image has been multilayer-transferred moves to the secondary transfer unit23. Meanwhile, the recording paper P accommodated in the accommodation portion32is fed by the paper feeding roller34and is transported to a contact portion between the secondary transfer roller26and the surface20S of the intermediate transfer belt20at a predetermined time by the plurality of transport rollers36. Then, a secondary transfer bias is applied to the support roller24and thus the toner image on the surface20S of the intermediate transfer belt20is transferred onto the recording paper P.

After that, the recording paper P is sent to the nip portion where the fixation member52and the pressing member54come into pressure-contact with each other. Accordingly, the toner image is fixed onto the recording paper P, and a color image is formed. The recording paper P on which fixation of the color image is finished is transported out to a discharge portion and a series of color image forming operations ends.

Cleaning Device

Next, the configuration of the cleaning device60will be described in detail.

As shown inFIGS.2and3, the cleaning device60removes toner remaining on the surface20S of the intermediate transfer belt20. The cleaning device60includes a housing70, a cleaning member90, a transport auger100, and a plurality of stirring augers110.

An arrow U appropriately shown in each drawing shows an upper side of the cleaning device60and an arrow F shows a front side of the cleaning device60. In addition, the transport auger100is an example of a transport member, and the stirring auger110is an example of a stirring member.

Housing

The housing70is formed of resin, for example. The housing70is formed in a straight body shape of which a longitudinal direction is parallel to an axial direction (direction along arrow W inFIG.4) of a rotary shaft24A of the intermediate transfer belt20. Inside the housing70, a storage chamber84for storage of waste toner T, which will be described later, is provided.

The intermediate transfer belt20is rotatably supported by the support roller24. Therefore, in the present exemplary embodiment, the rotary shaft24A of the support roller24is a rotary shaft of the intermediate transfer belt20.

The housing70includes a front wall portion72, a rear wall portion74, a bottom wall portion76, and a top wall portion78. The front wall portion72and the rear wall portion74face each other in a front-rear direction (direction along arrow F) of the cleaning device60. Upper end portions of the front wall portion72and the rear wall portion74are connected to each other by the top wall portion78. Meanwhile, lower end portions of the front wall portion72and the rear wall portion74are connected to each other by the bottom wall portion76. The bottom wall portion76faces the top wall portion78in a vertical direction (direction along arrow U).

An opening80is formed in a portion of the housing70that is on the intermediate transfer belt20side, that is, the front wall portion72of the housing70. The opening80penetrates the front wall portion72in a thickness direction. In addition, the opening80is formed in a rectangular shape, and is formed over a range from one end side to the other end side of the housing70in the longitudinal direction (direction along arrow W inFIG.4). A portion of the support roller24and a portion of the intermediate transfer belt20are disposed inside the housing70via the opening80.

Cleaning Member

The cleaning member (cleaning blade)90is formed of an elastic member such as rubber, is formed in a plate shape, and is disposed on a front end side in the housing70. The cleaning member90is disposed along the vertical direction of the housing70. In addition, a lower end portion of the cleaning member90is supported (fixed) by the bottom wall portion76of the housing70via a bracket92such as a metal plate. The cleaning member90can be elastically deformed (vibrated) in the thickness direction (front-rear direction of housing70).

The cleaning member90may be disposed along a direction inclined with respect to the vertical direction of the housing70instead of being disposed along the vertical direction of the housing70.

An upper end portion90U of the cleaning member90is a free end portion. In addition, a corner portion (edge portion) of the upper end portion90U of the cleaning member90that is on the intermediate transfer belt20side (front side) is a contact portion90U1that comes into contact with the surface20S of the intermediate transfer belt20. In the housing70, the contact portion90U1comes into contact with the surface20S of the intermediate transfer belt20from a downstream side in the rotation direction (direction along arrow R) of the intermediate transfer belt20.

In addition, the contact portion90U1of the cleaning member90comes into contact with the surface20S of the intermediate transfer belt20in a state where the cleaning member90is slightly bent toward a rear side of the housing70(in state where cleaning member90is elastically deformed). A height (length in vertical direction) of the cleaning member90is set to a predetermined value or more so that the amount of bending of the cleaning member90is secured.

As shown inFIG.4, the contact portion90U1of the cleaning member90comes into contact with the surface20S of the intermediate transfer belt20along the axial direction (direction along arrow W) of the rotary shaft24A. In addition, the contact portion90U1of the cleaning member90comes into contact with the surface20S of the intermediate transfer belt20over a range from one end20S1side to the other end20S2side in a width direction (direction along arrow W) of the surface20S. In addition, the intermediate transfer belt20and the cleaning member90are disposed over a range from one end side70E1and the other end side70E2in the longitudinal direction (direction along arrow W) of the housing70of the cleaning device60.

As shown inFIG.2, the intermediate transfer belt20rotates as shown by the arrow R to pass through the contact portion90U1of the cleaning member90in a direction from an upper side to a lower side. Accordingly, toner (residual toner) remaining on the surface20S of the intermediate transfer belt20is scraped off by the contact portion90U1and removed from the surface20S.

The intermediate transfer belt20and the cleaning member90face the rear wall portion74of the housing70. The storage chamber84is formed between the intermediate transfer belt20, the cleaning member90, and the rear wall portion74of the housing70. In addition, toner (hereinafter, referred to as “waste toner T”) that is removed from the surface20S of the intermediate transfer belt20by the contact portion90U1of the cleaning member90falls into the storage chamber84from the upper end portion90U of the cleaning member90and is stored in the storage chamber84.

A seal member82is provided at an end portion of the top wall portion78of the housing70, the end portion being on the opening80side. The seal member82is formed by, for example, a film or the like. In addition, the seal member82extends from the end portion of the top wall portion78of the housing70and covers a gap between the end portion and the surface20S of the intermediate transfer belt20. The seal member82prevents the waste toner T stored in the storage chamber84from flowing out to the outside of the housing70.

Transport Auger

The transport auger100is provided at an upper portion in the housing70. The transport auger100transports the waste toner T to one side in an axial direction along an axis G1while rotating around the axis G1so as to transport the waste toner T stored in the storage chamber84to the outside of the housing70, the axis G1extending along the axial direction of the rotary shaft24A of the intermediate transfer belt20.

Specifically, the transport auger100is, for example, a screw conveyor with a shaft. In addition, the transport auger100is disposed on a side opposite to the intermediate transfer belt20with respect to the contact portion90U1of the cleaning member90. The transport auger100includes a rotary shaft102and a transport blade104.

The rotary shaft102is formed in a columnar shape, and is disposed along the axial direction of the rotary shaft24A of the intermediate transfer belt20. In addition, both end portions of the rotary shaft102are rotatably supported by bearings (not shown) provided in the housing70. The rotary shaft102rotates around the axis G1extending along the axial direction (direction along arrow W inFIG.4) of the rotary shaft24A of the intermediate transfer belt20.

The transport blade104is formed in a spiral shape centered on the axis G1and is attached to an outer peripheral surface of the rotary shaft102. In a case where the transport blade104rotates around the axis G1, the waste toner T lifted up by the transport blade104is transported to the one side in the axial direction along the axis G1.

As shown inFIG.4, the waste toner T transported by the transport auger100is collected into a waste toner collection box58. The waste toner collection box58is disposed on one side in the longitudinal direction of the housing70. In the waste toner collection box58, one end side of the transport auger100in the axial direction is disposed. Accordingly, the waste toner T transported by the transport auger100is collected into the waste toner collection box58.

Here, as shown inFIG.2, the transport auger100transports, to the waste toner collection box58(refer toFIG.4) outside the housing70, the waste toner T stored in the storage chamber84in the housing70at a position above the contact portion90U1of the cleaning member90.

Specifically, the transport blade104of the transport auger100is formed in a circular shape as seen in the axial direction of the rotary shaft102. The waste toner T stored above a lower end of a trajectory of rotation drawn by an outer peripheral edge104E of the transport blade104is transported by the transport blade104. That is, the waste toner T stored below the lower end of the trajectory of rotation drawn by an outer peripheral edge104E of the transport blade104is stored in the storage chamber84without being transported by the transport auger100.

In addition, in the present exemplary embodiment, the lower end of the trajectory of rotation drawn by the outer peripheral edge104E of the transport blade104is disposed above the contact portion90U1of the cleaning member90. That is, a height H2between the bottom wall portion76of the housing70and the lower end of the trajectory of rotation drawn by the outer peripheral edge104E of the transport blade104is larger than a height H1between the bottom wall portion76of the housing70and the contact portion90U1of the cleaning member90(H2>H1).

Accordingly, the waste toner T is stored in the storage chamber84until a position (height H2) higher than the height H1of the contact portion90U1of the cleaning member90is reached. In addition, in a case where a storage height h of the stored waste toner T reaches the height H1of the contact portion90U1of the cleaning member90, the contact portion90U1of the cleaning member90is buried in the waste toner T.

In addition, as shown by an arrow R1, the transport auger100rotates around the axis G1such that a lower end of the transport blade104moves toward the contact portion90U1of the cleaning member90with respect to an upper end of the transport blade104. Accordingly, the waste toner T lifted up by the transport blade104is likely to move toward the contact portion90U1of the cleaning member90.

Note that, the transport auger100may rotate around the axis G1such that the lower end of the transport blade104moves toward a side opposite to the contact portion90U1of the cleaning member90with respect to the upper end of the transport blade104. In addition, the transport auger100is not limited to a screw conveyor with a shaft and may be a shaftless screw conveyor (coil auger) or the like.

Stirring Auger

The plurality of (two in the present exemplary embodiment) stirring augers110are provided at a lower portion in the housing70. The plurality of stirring augers110stir the waste toner T stored in the storage chamber84below the transport auger100. In addition, each stirring auger110stirs the waste toner T stored in a lower portion of the storage chamber84while rotating around an axis G2extending along the axial direction (direction along arrow W inFIG.4) of the rotary shaft24A of the intermediate transfer belt20.

Specifically, the plurality of stirring augers110are disposed in the storage chamber84between the rear wall portion74of the housing70and the cleaning member90. In addition, the plurality of stirring augers110are disposed beside the cleaning member90at an interval in the vertical direction. Furthermore, the plurality of stirring augers110are disposed such that the stirring auger110on an upper side is positioned below the contact portion90U1of the cleaning member90entirely. Each stirring auger110includes a rotary shaft112and a plurality of stirring blades114.

The rotary shaft112is formed in a columnar shape, and is disposed along the axial direction of the rotary shaft24A of the intermediate transfer belt20. In addition, both end portions of the rotary shaft112are rotatably supported by bearings (not shown) provided in the housing70. The rotary shaft112rotates around the axis G2extending along the axial direction (direction along arrow W inFIG.4) of the rotary shaft24A of the intermediate transfer belt20.

Each of the plurality of (two in the present exemplary embodiment) stirring blades114are formed in a plate shape and is disposed along the axial direction along the axis G2. In addition, as seen in the axial direction along the axis G2, the plurality of stirring blades114extend radially outward from an outer peripheral surface of the rotary shaft112while being centered on the axis G2. In a case where the transport blades104rotate around the axis G2, the waste toner T is lifted up and stirred by the stirring blades114. Note that the stirring auger110stirs the waste toner T without transporting the waste toner T in the axial direction along the axis G2.

As shown by an arrow R2, the stirring augers110that are adjacent to each other in the vertical direction rotate in opposite directions around the respective axes G2. Accordingly, the waste toner T is stirred in one direction (direction opposite to direction along arrow F) between the stirring augers110that are adjacent to each other in the vertical direction.

In addition, the transport auger100and the stirring auger110that are adjacent to each other in the vertical direction rotate in opposite directions around the respective axes G1and G2. Accordingly, the waste toner T is stirred in one direction (direction along arrow F) between the transport auger100and the stirring auger110that are adjacent to each other in the vertical direction.

Note that the stirring augers110that are adjacent to each other in the vertical direction may rotate in the same direction around the respective axes G2. Similarly, the transport auger100and the stirring auger110that are adjacent to each other in the vertical direction may rotate in the same direction around the respective axes G1and G2.

Action

Next, the action of the cleaning device according to the present exemplary embodiment will be described.

As shown inFIG.2, the contact portion90U1of the cleaning member90comes into contact with the surface20S of the intermediate transfer belt20from the downstream side in the rotation direction of the intermediate transfer belt20. In a case where the intermediate transfer belt20rotates in a direction along the arrow R in such a state, toner remaining on the surface20S of the intermediate transfer belt20is scraped off by the contact portion90U1of the cleaning member90. Toner t scraped off by the contact portion90U1of the cleaning member90temporarily stays at the contact portion90U1and then is stored into the storage chamber84in the housing70over the upper end portion90U of the cleaning member90.

Here, the toner t temporarily staying at the contact portion90U1functions as a lubricant that reduces a frictional force generated between the surface20S of the intermediate transfer belt20and the contact portion90U1of the cleaning member90. Accordingly, the contact portion90U1of the cleaning member90being dragged by the surface20S of the intermediate transfer belt20in the rotation direction (direction along arrow R) of the intermediate transfer belt20is suppressed.

Meanwhile, for example, in a case where a low-resolution low-density image is continuously printed, the amount of toner remaining on the surface20S of the intermediate transfer belt20is reduced. As a result, the amount of the toner t staying at the contact portion90U1of the cleaning member90is reduced, and a frictional force generated between the surface20S of the intermediate transfer belt20and the contact portion90U1of the cleaning member90is increased.

Accordingly, the contact portion90U1of the cleaning member90may be dragged by the surface20S of the intermediate transfer belt20in the rotation direction (direction along arrow R) of the intermediate transfer belt20and the cleaning member90may be bent to be rolled up. In addition, in a case where the cleaning member90is bent to be rolled up, the removal efficiency of the cleaning member90which removes toner remaining on the surface20S of the intermediate transfer belt20may be decreased and the surface20S of the intermediate transfer belt20may be poorly cleaned.

On the other hand, in the present exemplary embodiment, the transport auger100is provided above the storage chamber84of the housing70. Here, as shown inFIG.2, the transport auger100transports, to the waste toner collection box58(refer toFIG.4) outside the housing70, the waste toner T stored in the storage chamber84in the housing70at a position above the contact portion90U1of the cleaning member90that comes into contact with the surface20S of the intermediate transfer belt20.

Accordingly, as shown inFIGS.2and3, the waste toner T is stored in the storage chamber84until a position (height H2) higher than the height H1of the contact portion90U1of the cleaning member90is reached. In addition, in a case where the storage height h of the stored waste toner T reaches the height H1of the contact portion90U1of the cleaning member90, the contact portion90U1of the cleaning member90is constantly buried in the waste toner T. That is, a state where the waste toner T as a lubricant is constantly supplied to the contact portion90U1of the cleaning member90is achieved.

Therefore, in the case of the present exemplary embodiment, an increase in frictional force generated between the surface20S of the intermediate transfer belt20and the contact portion90U1of the cleaning member90is suppressed even in a case where a low-resolution low-density image is continuously printed in comparison with a case where the storage height h of the waste toner T is smaller than the height H1of the contact portion90U1of the cleaning member90.

As a result, a probability that the contact portion90U1of the cleaning member90is dragged by the surface20S of the intermediate transfer belt20in the rotation direction (direction along arrow R) of the intermediate transfer belt20and the cleaning member90is bent to be rolled up is suppressed. Therefore, poor cleaning of the surface20S of the intermediate transfer belt20is suppressed.

In addition, in the present exemplary embodiment, the waste toner T removed from the surface20S of the intermediate transfer belt20is supplied, as a lubricant, to the contact portion90U1of the cleaning member90. Therefore, in the case of the present exemplary embodiment, the amount of toner to be used may be reduced and poor cleaning of the intermediate transfer belt20may be suppressed in comparison with a configuration in which toner different from toner removed from the surface20S of the intermediate transfer belt20is supplied to, as a lubricant material, the contact portion90U1of the cleaning member90.

Note that, until the storage height h of the waste toner T stored in the storage chamber84reaches the height H1of the contact portion90U1of the cleaning member90, an event as follows occurs, for example. That is, independently of the above-described color image forming operations of the image forming apparatus40, toner is supplied to a region (region from which no transfer to recording paper P occurs) other than a toner image forming region on the surface20S of the intermediate transfer belt20from at least one of the first to fourth image forming units10Y,10M,10C, or10K at a predetermined time. Accordingly, for example, an increase in frictional force generated between the surface20S of the intermediate transfer belt20and the contact portion90U1of the cleaning member90is suppressed even in a case where a low-resolution low-density image is continuously printed.

In addition, the transport auger100transports the waste toner T to the one side in the axial direction along the axis G1while rotating around the axis G1extending along the axial direction of the rotary shaft24A of the intermediate transfer belt20. Accordingly, in the case of the present exemplary embodiment, the size of the housing70may be reduced in comparison with a configuration in which the transport auger100transports the waste toner T in a direction different from the axial direction along the axis G1.

Furthermore, as shown by the arrow R1, the transport auger100rotates around the axis G1such that a lower end of the transport auger100moves toward the contact portion90U1with respect to an upper end of the transport auger100. Accordingly, in the case of the present exemplary embodiment, the waste toner T is easily supplied to the contact portion90U1of the cleaning member90in comparison with a configuration in which the transport auger100rotates around the axis G1such that the lower end of the transport auger100moves toward a side (side opposite to arrow R1) opposite to the contact portion90U1of the cleaning member90with respect to the upper end of the transport auger100.

In addition, the cleaning member90is disposed along the vertical direction as seen in the axial direction of the rotary shaft24A of the intermediate transfer belt20. Accordingly, in the case of the present exemplary embodiment, the size of the housing70may be reduced in comparison with a configuration in which the cleaning member90is disposed along a direction inclined with respect to the vertical direction as seen in the axial direction of the rotary shaft24A of the intermediate transfer belt20.

In addition, the plurality of stirring augers110are provided in the storage chamber84of the housing70. Below the transport auger100, the plurality of stirring augers110stir the waste toner T stored in the storage chamber84while rotating around the respective axes G2. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T is suppressed in comparison with a configuration in which the waste toner T is simply stored in the storage chamber84of the housing70.

Furthermore, as shown by the arrow R2, the stirring augers110that are adjacent to each other in the vertical direction rotate in opposite directions around the respective axes G2. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T is suppressed between the stirring augers110adjacent to each other in comparison with a configuration in which the stirring augers110adjacent to each other rotate in the same direction.

Furthermore, as shown by the arrow R1and the arrow R2, the transport auger100and the stirring auger110that are adjacent to each other in the vertical direction rotate in opposite directions. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T is suppressed between the transport auger100and the stirring auger110in comparison with a configuration in which the transport auger100and the stirring auger110rotate in the same direction.

Here, in a case where the intermediate transfer belt20rotates in a state where the contact portion90U1of the cleaning member90is in contact with the surface20S of the intermediate transfer belt20, the cleaning member90vibrates (is elastically deformed) in the front-rear direction (direction along arrow F) of the housing70. Accordingly, in the case of the present exemplary embodiment, the removal efficiency of the cleaning member90which removes toner remaining on the surface20S of the intermediate transfer belt20is improved in comparison with a configuration in which the cleaning member90does not vibrate in the front-rear direction of the housing70.

Meanwhile, in a case where adhesion of the waste toner T stored in the storage chamber84beside the cleaning member90occurs, it becomes difficult for the cleaning member90to vibrate in the front-rear direction of the housing70. As a result, the removal efficiency of the cleaning member90which removes toner on the surface20S of the intermediate transfer belt20may be decreased.

With regard to this, in the present exemplary embodiment, the stirring augers110are disposed in the storage chamber84between the cleaning member90and the rear wall portion74of the housing70. That is, the stirring augers110are disposed beside the cleaning member90. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T beside the cleaning member90is suppressed in comparison with a configuration in which the stirring augers110are disposed above the cleaning member90. Therefore, a decrease in removal efficiency of the cleaning member90which removes toner on the surface20S of the intermediate transfer belt20is suppressed.

In addition, the plurality of stirring augers110are disposed beside the cleaning member90in the vertical direction. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T beside the cleaning member90is suppressed in comparison with a configuration in which one stirring auger110is disposed beside the cleaning member90.

Furthermore, beside the cleaning member90, the plurality of stirring augers110are disposed such that the stirring auger110on the upper side is positioned below the contact portion90U1of the cleaning member90entirely. Accordingly, in the case of the present exemplary embodiment, adhesion of the waste toner T beside the cleaning member90is suppressed in comparison with a configuration in which the stirring auger110on the upper side is disposed above the contact portion90U1of the cleaning member90entirely or partially.

Modification Example

Next, a modification example of the above-described exemplary embodiment will be described.

FIG.5shows stirring augers120that are adjacent to each other in the vertical direction. Each stirring auger120includes a rotary shaft122and comb-shaped stirring blades124extending in an axial direction of the rotary shaft122. The stirring augers120adjacent to each other are disposed such that trajectories of rotation of the respective comb-shaped stirring blades124overlap with each other as seen in an axial direction along the axis G2as shown by two-dot chain lines. The stirring auger120is an example of a stirring member.

As shown inFIG.6, the comb-shaped stirring blade124includes a plurality of recess portions124A and protrusion portions124B alternately arranged in the axial direction of the rotary shaft122. Regarding the stirring augers120adjacent to each other, the protrusion portions124B of the respective comb-shaped stirring blades124are disposed so as to be offset from each other in the axial direction along the axis G2so that interference therebetween is prevented. Accordingly, in a case where the stirring augers120adjacent to each other rotate around the respective axes G2, the protrusion portions124B of one stirring auger120pass through the recess portions124A of the other stirring auger120.

As described above, in the present modification example, the trajectories of rotation of the comb-shaped stirring blades124of the stirring augers120adjacent to each other are disposed to overlap with each other as seen in the axial direction along the axes G2of the stirring augers120. Accordingly, in the case of the present exemplary embodiment, the size of a region where the waste toner T is not stirred is reduced in comparison with a configuration in which the trajectories of rotation of the comb-shaped stirring blades124of the stirring augers120adjacent to each other are separated from each other in the vertical direction as seen in the axial direction along the axes G2of the stirring augers120.

Note that, in a case where the trajectories of rotation of the comb-shaped stirring blades124of the stirring augers120adjacent to each other overlap with each other as seen in the axial direction along the axes G2of the stirring augers120as in the present modification example, three stirring augers120can be disposed in the vertical direction in the housing70shown inFIG.2, for example. Therefore, adhesion of the waste toner T stored in the storage chamber84of the housing70is further suppressed.

In addition, in the above-described exemplary embodiment, stirring forces of the stirring augers110adjacent to each other are the same as each other. However, for example, it is preferable that a stirring force of one of the plurality of stirring augers110that is positioned at a lowermost position is larger than stirring forces of the other stirring augers110.

Here, a stirring force of the stirring auger110means an external force that acts on the waste toner T from the stirring blade114of the stirring auger110as the stirring auger110rotates and the larger the stirring force of the stirring auger110is, the larger a stirring range of the stirring auger110is. The stirring force of the stirring auger110increases as a circumferential speed of an outer peripheral edge114E of the stirring blade114increases.

Therefore, for example, in a case where two stirring augers110are disposed in the vertical direction as shown inFIG.2, a rotation speed of the stirring auger110on a lower side is made higher than a rotation speed of the stirring auger110on an upper side. Alternatively, a radial length of the stirring blade114of the stirring auger110on the lower side is made larger than a radial length of the stirring blade114of the stirring auger110on the upper side in a state where the rotation speeds of the stirring augers110on the upper and lower sides are the same as each other. Alternatively, the rotation speed of the stirring auger110on the lower side is made higher than the rotation speed of the stirring auger110on the upper side and the radial length of the stirring blade114of the stirring auger110on the lower side is made larger than the radial length of the stirring blade114of the stirring auger110on the upper side.

Accordingly, a circumferential speed of the outer peripheral edge114E of the stirring blade114of the stirring auger110on the lower side is made higher than a circumferential speed of the outer peripheral edge114E of the stirring blade114of the stirring auger110on the upper side. As a result, a stirring force of the stirring auger110on the lower side is made larger than a stirring force of the stirring auger110on the upper side, and a stirring range of the stirring auger110on the lower side is made larger than a stirring range of the stirring auger110on the upper side.

Therefore, in the case of the present modification example, adhesion of the waste toner T stored in the lower portion of the storage chamber84is suppressed in comparison with a configuration in which the stirring forces of the stirring augers110adjacent to each other are the same as each other.

In addition, in the above-described exemplary embodiment, the transport auger100transports the waste toner T stored in the storage chamber84in the housing70to the outside of the housing70at a position above the contact portion90U1of the cleaning member90. However, the transport auger100may transport the waste toner T stored in the storage chamber84in the housing70to the outside of the housing70at the same height as the contact portion90U1of the cleaning member90. That is, the height H2of the lower end of the trajectory of rotation drawn by the outer peripheral edge104E of the transport blade104may be the same as the height H1of the contact portion90U1of the cleaning member90(H2=H1).

In addition, in the above-described exemplary embodiment, the housing70is provided with the plurality of stirring augers110. However, the housing70may be provided with at least one stirring auger110. In addition, for example, it is desirable that at least a portion of the stirring auger110is positioned below the contact portion90U1of the cleaning member90for suppression of adhesion of the waste toner T beside the cleaning member90. Note that, the stirring auger110only has to be provided as needed and may be omitted as appropriate.

In addition, in the above-described exemplary embodiment, an image holder is the intermediate transfer belt20. However, the image holder is not limited to the intermediate transfer belt20, and may be a direct transfer belt or a photoreceptor.

Although one exemplary embodiment of the present disclosure has been described above, the present disclosure is not limited to such an exemplary embodiment, the one exemplary embodiment and various modification examples may be used in combination as appropriate, and it is a matter of course that various exemplary embodiments can be implemented without departing from the gist of the present disclosure.