JP6809031B2 - Belt device, transfer device and image forming device - Google Patents

Description

The present invention relates to a belt device, a transfer device, and an image forming device.

In the belt device, tension is applied to a belt member wound around a plurality of rotating bodies by a tension roller serving as a tension applying member, and a plurality of cleaning units provided with cleaning members are spaced apart in the belt moving direction. (For example, Patent Document 1).

Since tension is applied to the belt member by the tension roller, when the force applied to the belt member changes, the position of the tension roller changes accordingly. When the position of the tension roller changes in this way, the trajectory of the belt changes, so that the contact state between the cleaning member and the belt member changes before and after the belt displacement, which causes poor cleaning of the belt member. Sometimes.
An object of the present invention is to prevent poor cleaning even when a plurality of cleaning members are used for the belt member.

To achieve the above object, a belt device according to the present invention includes a belt unit having a belt member that is wound around a plurality of rotating bodies including the tension roller, said tension roller abuts via the belt member the belt member has a first cleaning member for cleaning and a first cleaning unit supported on the belt unit, wherein the rotating body and the contact that is different from the tension roller via the belt member, the belt member The first side plate supporting the first cleaning unit and the tension roller are connected to each other and include a second cleaning unit having a second cleaning member for cleaning the belt unit and being supported by the belt unit . The cleaning unit can be displaced according to the displacement of the tension roller, the second cleaning unit is supported by a second side plate different from the first side plate, and the tension roller is displaced in the second cleaning unit. It is also characterized by not being displaced .

According to the present invention, even when a plurality of cleaning members are used for the belt member, the contact state between the plurality of cleaning members and the belt member is stable, and cleaning defects can be prevented.

The schematic block diagram which shows one Embodiment of the image forming apparatus which includes the transfer apparatus which is the belt apparatus which concerns on this invention. The external perspective view which shows the structure of the transfer apparatus which concerns on this invention. External view of the transfer device as viewed from the axial direction. The figure explaining the structure of the main part of a transfer apparatus. The figure explaining the relationship between a belt member and a tension applying member. The figure for explaining the problem. The positional relationship between the belt member and the cleaning member is shown, (a) is a diagram showing a change in the belt member and the locus due to displacement of the tension applying member, and (b) is an arrangement of the second cleaning member in the present embodiment. The figure to explain. The plan view which shows the structure of the 1st cleaning unit schematically. The perspective view explaining the structure of the 1st cleaning unit. The figure explaining the positional relationship between a tension applying member and a cleaning member. It is a figure explaining the structure of the fixed part of the shaft part of the tension applying member, and the 1st cleaning unit. The enlarged perspective view explaining the support structure of the shaft part of the tension applying member. The plan view which shows typically the whole structure of the 2nd cleaning unit. The perspective view explaining the structure of the main part of the 2nd cleaning unit. The perspective view which shows the whole structure of the 2nd cleaning unit. The external view explaining the mounting structure of the 2nd cleaning unit. A partially enlarged perspective view illustrating the mounting structure of the second cleaning unit. The figure explaining the positional relationship between the 2nd cleaning unit and the facing roller. The perspective view explaining the structure of the attachment / detachment means. The figure which looked at the structure of the attachment / detachment means from the axial direction. It is a figure explaining the operation of the contacting and separating means, (a) shows a separated state, and (b) shows a contact state. The perspective view explaining the whole structure of the nip pressure adjusting means. The figure explaining the structure of the main part of the nip pressure adjusting means. It is a figure explaining the operation of the nip pressure adjusting means, (a) shows the state at the time of low pressure, (b) shows the state at the time of increasing pressure.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the embodiment, the same functions and the same configurations are designated by the same reference numerals, and duplicate description will be omitted as appropriate. Drawings may be partially omitted to aid in understanding some configurations. In the figure, Y, M, C, and K are subscripts attached to the constituent members corresponding to yellow, magenta, cyan, and black, and are omitted as appropriate.

The electrophotographic color printer (hereinafter referred to as “printer”) 100 as the image forming apparatus according to the present invention forms a toner image of yellow (Y), magenta (M), cyan (C), and black (K). A transfer device 40 including four image forming units 1Y, 1M, 1C, 1K, an intermediate transfer unit 30 as an intermediate transfer device, a secondary transfer unit 41 as a belt unit, and a secondary transfer unit 41. It includes a plurality of cleaning units to be used, a cassette 60 for storing the recording material P, a fixing device 90, and the like.
The four image forming units 1Y, 1M, 1C, and 1K are powders and use toners of different colors Y, M, C, and K as the developing agent, but other than that, they have the same configuration. It will be replaced when it reaches the end of its life. That is, the four image forming units 1Y, 1M, 1C, and 1K are detachably provided with respect to the printer main body 100A as the image forming apparatus main body, and are interchangeable.

The image forming units 1Y, 1M, 1C, and 1K are drum-shaped photoconductors 2Y, 2M, 2C, 2K, drum cleaning devices 3Y, 3M, 3C, 3K, static eliminators, charging devices 6Y, 6M, 6C, which are image carriers. , 6K, developing devices 8Y, 8M, 8C, 8K and the like. The image forming units 1Y, 1M, 1C, and 1K form a process cartridge unit in which these plurality of devices are held by a common holder and can be integrally attached to and detached from the printer main body 100A, and can be replaced in units of units. It is possible.

The photoconductors 2Y, 2M, 2C, and 2K are rotationally driven in the counterclockwise direction in the drawing by a driving means such as a motor. In the charging devices 6Y, 6M, 6C, 6K, the charging roller and the photoconductor 2Y, 2M, 2C are brought into contact with or close to the photoconductors 2Y, 2M, 2C, and 2K while the charging roller, which is a charging member to which the charging bias is applied, is in contact with or close to the photoconductors 2Y, 2M, 2C, and 2K. By generating a discharge between 2K and 2K, the surfaces of the photoconductors 2Y, 2M, 2C and 2K are uniformly charged. A method using a charging charger may be adopted instead of the method in which a charging member such as a charging roller is brought into contact with or close to the photoconductors 2Y, 2M, 2C, and 2K.

The surfaces of the photoconductors 2Y, 2M, 2C, and 2K uniformly charged by the charging devices 6Y, 6M, 6C, and 6K are the optical writing units 101 arranged above the image forming units 1Y, 1M, 1C, and 1K. An electrostatic latent image for each color is formed by light scanning with exposure light such as laser light emitted from. This electrostatic latent image is developed by developing devices 8Y, 8M, 8C, and 8K having toners of each color to obtain a toner image T as an image of each color. A toner image is formed on the photoconductor 2. The toner image T of the photoconductors 2Y, 2M, 2C, and 2K is primarily transferred and supported on the front surface 31a of the intermediate transfer belt 31 made of an endless belt member.
The drum cleaning device 3Y, 3M, 3C, and 3K removes the transfer residual toner adhering to the surface of the photoconductors 2Y, 2M, 2C, and 2K after undergoing the primary transfer step (primary transfer nip described later). is there. The static eliminator is a well-known device that removes residual charges of the photoconductors 2Y , 2M, 2C, and 2K after being cleaned by the drum cleaning device 3Y , 3M, 3C, and 3K. The surfaces of the photoconductors 2Y, 2M, 2C, and 2K are initialized by this static elimination to prepare for the next image formation.

Below the image forming units 1Y, 1M, 1C, and 1K, the intermediate transfer belt 31 is stretched to move endlessly (rotate) in the clockwise direction in the drawing, and the transfer unit 30 is a primary transfer device. Are arranged. The transfer unit 30 is also referred to as a primary transfer unit or an intermediate transfer unit. In the present embodiment, the rotational movement direction of the intermediate transfer belt 31 is the belt movement direction a.
The transfer unit 30 is detachable (replaceable) together with the printer body 100A. The transfer unit 30 includes a drive roller 32, a secondary transfer back surface roller 33, a cleaning backup roller 34, and four primary transfer rollers 35Y and 35M, in addition to the intermediate transfer belt 31 which is a belt-shaped image carrier and an intermediate transfer body. , 35C, 35K, pre-transfer roller 37 and the like.

The intermediate transfer belt 31 includes a drive roller 32, a secondary transfer back surface roller 33, a cleaning backup roller 34, a primary transfer roller 35Y, 35M, 35C, 35K and a pre-transfer roller 37 as rotating bodies arranged inside the loop. It is wrapped around and supported and stretched. Then, the drive roller 32, which is rotationally driven in the clockwise direction in the drawing by a drive means such as a drive motor, moves endlessly in the same direction and is conveyed. In the present embodiment, the intermediate transfer belt 31 is composed of an endless elastic belt having elasticity in which a plurality of layers are laminated, and the toner image on the photoconductors 2Y, 2M, 2C, and 2K is primarily transferred. It is an intermediate transcript.

The primary transfer rollers 35Y, 35M, 35C, and 35K sandwich the endlessly moved intermediate transfer belt 31 between the photoconductors 2Y, 2M, 2C, and 2K, and form a front surface forming an image-carrying surface of the intermediate transfer belt 31. The primary transfer nip N1 serving as the primary transfer portion for Y, M, C, and K in which 31a and the surfaces of the photoconductors 2Y, 2M, 2C, and 2K are in contact with each other is formed. A primary transfer bias is applied to each of the primary transfer rollers 35Y, 35M, 35C, and 35K from a well-known transfer bias power source. As a result, a transfer electric field is formed between the toner images of Y, M, C, and K on the photoconductors 2Y, 2M, 2C, and 2K and the primary transfer rollers 35Y, 35M, 35C, and 35K.

The Y toner image formed on the surface of the yellow photoconductor 2Y enters the yellow primary transfer nip N1 as the yellow photoconductor 2Y rotates. Then, by the action of the transfer electric field and the nip pressure, the primary transfer is performed from the yellow photoconductor 2Y onto the intermediate transfer belt 31. The intermediate transfer belt 31 on which the Y toner image is primarily transferred in this way then sequentially passes through the primary transfer nip N1 for M, C, and K. Then, the M, C, and K toner images on the photoconductors 2M, 2C, and 2K are sequentially superimposed on the Y toner image and primary transferred. By this superposition primary transfer, a four-color superposition toner image is formed on the intermediate transfer belt 31.
The image forming steps up to this point have been described on the premise that a four-color full-color image is formed. However, the printer 100 may form a single color toner image of any of yellow, magenta, cyan, and black, or a toner image using at least two colors of the toner, and transfer the toner image to the intermediate transfer belt 31. It is possible.

Below the outside of the loop of the intermediate transfer belt 31, a secondary transfer belt 406 made of a material harder than the resin intermediate transfer belt 31 which is a belt member and a transfer member (for example, a polyimide resin belt (PI belt)) is placed. A belt-type secondary transfer device 40 including the secondary transfer unit 41 provided is arranged. The secondary transfer unit 41 is a secondary transfer back surface roller 33 and a secondary transfer arranged inside the loop of the intermediate transfer belt 31. The intermediate transfer belt 31 is sandwiched between the transfer belts 406 to form a secondary transfer nip N2 which is a transfer portion where the front surface 31a of the intermediate transfer belt 31 and the secondary transfer belt 406 come into contact with each other. In the embodiment, a secondary transfer bias is applied to the secondary transfer back surface roller 33 by a power supply 39 as a transfer bias output means, whereby a minus is applied between the secondary transfer back surface roller 33 and the secondary transfer belt 406. A secondary transfer electric field is formed that electrostatically moves the polarly charged toner from the secondary transfer back surface roller 33 side toward the secondary transfer belt 406 side. In the present embodiment, the secondary transfer portion is the secondary transfer portion. At the transfer nip N2, the toner image on the intermediate transfer belt 31 is secondarily transferred to the recording material P. The intermediate transfer belt 31 forms the secondary transfer nip N2 with the secondary transfer belt 406 which is a transport belt. It is an image carrier, and is also an intermediate transfer body on which the toner image on the photoconductors 2Y, 2M, 2C, and 2K is primarily transferred. The toner image transferred to the secondary transfer belt 406 is used for image density measurement. It is a toner image to be used.

In the present embodiment, the secondary transfer back surface roller 33 is configured to apply the bias used for the secondary transfer (secondary transfer bias) from the power supply 39, but is arranged to face the secondary transfer back surface roller 33. A bias may be applied to the secondary transfer roller 405 from the power supply 39. When applying a secondary transfer bias to the secondary transfer roller 405, a secondary transfer bias having a polarity opposite to that of the toner is applied, and when applying a transfer bias to the secondary transfer back surface roller 33, it is the same as the toner. Apply a polar bias. The secondary transfer roller 405 is also referred to as a nip forming roller.

Below the transfer device 40, a cassette 60 that serves as an accommodating portion that can accommodate a plurality of recording materials P such as various types of paper and resin sheets in a bundle is arranged. In this cassette 60, the roller 60a is brought into contact with the recording material P at the top of the bundle, and the recording material P is moved from the cassette 60 to the secondary transfer nip N2 by rotationally driving the roller 60a at a predetermined timing. It is sent out toward the transport path 65. The recording material P sent out to the transport path 65 is sent out to the secondary transfer nip N2 at the timing synchronized with the toner image on the front surface 31a of the intermediate transfer belt 31 in the secondary transfer nip N2 by the resist roller pair 61. Is done. The recording material P is an object to be transported.

The toner image of the front surface 31a of the intermediate transfer belt 31 is collectively secondary transferred onto the recording material P by the secondary transfer nip N2 by the action of the secondary transfer electric field and the nip pressure, and is in full color in combination with the white color of the recording material P. It becomes a toner image. The transfer residual toner that has not been transferred to the recording material P is attached to the front surface 31a of the intermediate transfer belt 31 after passing through the secondary transfer nip N2. The transfer residual toner is cleaned from the belt surface by the intermediate belt cleaning device 38 that is in contact with the front surface 31a of the intermediate transfer belt 31.

A fixing device 90 is arranged on the downstream side of the recording material transport direction b with respect to the secondary transfer nip N2. The recording material P on which the toner image is transferred is sent to the fixing device 90. The fed recording material P is sandwiched between fixing nips in which the fixing roller 91 having a heat source inside and the pressure roller 92 come into contact with each other, and the toner in the full-color toner image is softened and fixed by heating and pressing. Toner. The recording material P after fixing is discharged from the inside of the fixing device 90 and discharged to the outside of the machine.

Next, the configuration of the transfer device 40 will be described in detail.
FIG. 2 is an external perspective view showing the configuration of the transfer device 40, FIG. 3 is an external view of the transfer device 40 viewed from the axial direction, and FIG. 4 is a diagram illustrating a configuration of a main part of the transfer device 40. Sign W in FIG. 2 is a longitudinal transfer device 40, which is axially definitive to the present embodiment. The transfer device 40 includes a secondary transfer unit 41, one cleaning unit (hereinafter referred to as “first cleaning unit”) 410, another cleaning unit (hereinafter referred to as “second cleaning unit”) 420, and a cleaning unit. It has 42. In the transfer device 40, the secondary transfer unit 41 and the first cleaning unit 410 are integrated, and the cleaning unit 42 and the second cleaning unit 420 are integrated so as to be removable from the printer main body 100A. There is. The first cleaning unit 410 is arranged on the upstream side of the secondary transfer belt 406 in the rotational movement direction with respect to the second cleaning unit 420. An upstream transfer guide member 46 is provided above the second cleaning unit 420 so as to be located upstream of the secondary transfer belt 406 (secondary transfer nip N2) in the recording material transport direction. The transfer device 40 is provided so that the downstream transfer guide member 47 is located on the downstream side in the recording material transfer direction with respect to the secondary transfer belt 406 (secondary transfer nip N2).
As shown in FIG. 4, the secondary transfer unit 41 includes a secondary transfer belt 406 as a belt member wound around a plurality of rotating bodies. In the present embodiment, the plurality of rotating bodies are a separation roller 401, a driven roller 402, a tension roller 403 constituting a first blade facing roller and a tension applying member, a second blade facing roller 404, and a secondary transfer roller 405. It is configured. The secondary transfer belt 406 is wound around the outer peripheral surfaces of these rollers, and tension is applied from the inside to the outside of the belt by the tension roller 403. The secondary transfer belt 406 also functions as a drive roller. That is, as shown in FIGS. 2 and 3, the secondary transfer roller 405 is counterclockwise in the drawing by transmitting the driving force from the driving source to the gear G1 provided at the end of the shaft 405A. It is rotationally driven in the circumferential direction and rotationally transfers the secondary transfer belt 406 in the counterclockwise direction in the figure.

As shown in FIG. 4, the separation roller 401, the driven roller 402, the second blade opposed roller 404, and the secondary transfer roller 405 are rotatably supported by a pair of side plates 409A and 409B located in the axial direction of each roller. There is. The tension roller 403 has a shaft portion 403A, and both ends of the shaft portion 403A are supported by a pair of holders 408A and 408B. The holders 408A and 408B are slidably supported by the pressure side plates 451A and 451B fixed to the side plates 409A and 409B. The sliding direction of the holders 408A and 408B is a direction in which the secondary transfer belt 406 is moved from the inside to the outside of the belt. Between the pressure side plates 451A and 451B and the holders 408A and 408B, one end is fixed to the pressure side plates 451A and 451B, and the other end is mounted on the holders 408A and 408B to apply tension to the tension roller 403. Pressurizing springs 452A and 452B, which are pressurizing members, are interposed. Therefore, the tension roller 403 pressurizes the secondary transfer belt 406 from the inside to the outside, and when an external force exceeding the tension of the tension roller 403 acts on the secondary transfer belt 406 from the secondary transfer belt 406 side, the belt It is configured to move from the outside toward the inside of the belt. The second blade facing roller 404 is arranged between the tension roller 403 and the secondary transfer roller 405, and its outer peripheral surface is brought into contact with the back surface 406a of the secondary transfer belt 406. That is, the tension roller 403 is provided so as to be displaceable in the direction opposite to the tension applying direction indicated by the arrow C.

The secondary transfer unit 41 is located in each axial direction and is movably supported by the unit frame 422 that constitutes the housing of the cleaning unit 42 with respect to the cleaning unit 42. This moving direction is a direction of advancing and retreating with respect to the secondary transfer back surface roller 33, and when changing the nip width and nip pressure of the secondary transfer nip N2, or when the secondary transfer belt 406 is attached to the intermediate transfer belt 31. It is also the direction of movement when abutting and separating.
The first cleaning unit 410 includes a first cleaning blade 411 which is a cleaning member. The first cleaning blade 411 is in contact with one end 411a, which is a part thereof, so as to bite into the surface 406b of the secondary transfer belt 406 at a position facing the tension roller 403. The second cleaning unit 420 includes a second cleaning blade 421 which is a cleaning member. The second cleaning blade 421 is in contact with one end 421a, which is a part thereof, so as to bite into the surface 406b of the secondary transfer belt 406 at a position facing the second blade facing roller 404.

The cleaning unit 42 includes a paper dust removing brush 43 as a paper dust removing member, a lubricant applying unit 44, and a collecting unit 45. The paper dust removing brush 43 is configured by providing a brush on the outer peripheral surface of the tubular portion, and is in contact with the surface 406b of the secondary transfer belt 406. The paper dust removing brush 43 is arranged on the upstream side of the secondary transfer belt 406 in the moving direction with respect to the first cleaning unit 410, and removes paper dust which is one of the foreign substances adhering to the surface 406b of the secondary transfer belt 406. It is mainly removed. The paper dust removing brush 43 is configured to rotate in a driven manner as the secondary transfer belt 406 moves, but the paper dust removing brush 43 may be rotationally driven in the counter direction with respect to the moving direction of the secondary transfer belt 406.

The lubricant coating unit 44 is a well-known one that supplies the lubricant 442 to the surface 406b of the secondary transfer belt 406 by the lubrication brush 441, which is a lubrication coating member, between the first cleaning unit 410 and the second cleaning unit 420. is there.
The collection unit 45 is arranged below the contact portion between the first cleaning blade 411 and the secondary transfer belt 406, and is scraped with the paper dust collected by the paper dust removing brush 43 or the first cleaning blade 411. It is provided with a space portion 451 in which the removed transfer residual toner falls and accumulates. A waste toner transport screw 452 is provided as a collection member inside the space portion 451 to transport foreign matter (paper dust / toner) accumulated in the space portion 451 to a waste toner tank provided in the printer main body 100A. It is configured to do.
In this way, in the transfer device 40 that cleans the secondary transfer belt 406 tensioned by the tension roller 403 using a plurality of cleaning members such as the first cleaning blade 411 and the second cleaning blade 421. The toner that has passed through the first cleaning blade 411 arranged on the upstream side is scraped off by the second cleaning blade 421 arranged on the downstream side, so that the cleaning property is improved.

By the way, as shown in FIG. 5, the position of the tension roller 403 is determined by the inner circumference length of the secondary transfer belt 406, but there is a tolerance in the variation in the inner circumference length of the belt (in the present embodiment, ± 1 mm). However, the longer the inner circumference, the larger the tolerance. Due to such variation in the inner circumference of the belt, the contact state between the secondary transfer belt 406 and the cleaning blades 411 and 421 changes. That is, as shown in FIG. 6, when the position of the tension roller 403 changes, the trajectory of the secondary transfer belt 406 changes as shown in FIG. 7 (a). Therefore, as shown in FIG. 7 (b). The contact state with the cleaning blades 411 and 421 may change before and after the belt is displaced, which may cause cleaning failure.

In particular, when a plurality of cleaning blades 411 and 421 are used in the small transfer device 40 having the secondary transfer belt 406, it is difficult to provide dedicated opposing rollers for the cleaning blades 411 and 421, respectively, and in the present embodiment, the tension roller 403 is a first blade facing roller of the cleaning blade 411 , and the cleaning blade 421 is provided with a dedicated second blade facing roller 404. Of course, it is assumed that the positions of the opposing roller 404 and the tension roller 403 are interchanged. Thus, among the plurality of opposing rollers, one case is possible and the other is fixed arrangement moves and holds and supports the both, etc. In the same frame, with the change of the trajectory of the secondary transfer belt 406, a cleaning The positional relationship between the blade 421 and the opposing roller 404 is displaced, which causes poor cleaning.

(First Embodiment)
Therefore, in the present embodiment, as shown in FIG. 4, the first cleaning unit 410, which is one of the plurality of cleaning units, can be integrally moved with the tension roller 403 to be another cleaning unit. The second cleaning unit 420 is provided on the side plates 409A and 409B on the belt unit side, which are separate housings from the first unit side plates 412A and 412B that support the first cleaning unit 410 and the tension roller 403.
With such a configuration, even when a plurality of cleaning members of the first cleaning blade 411 and the second cleaning blade 421 are used for the secondary transfer belt 406, the cleaning blade 411 facing the tension roller 403 is a tension roller 403. Move in one piece. Further, the second cleaning blade 421, which is different from the first cleaning blade 411 facing the tension roller 403, does not move even if the position of the tension roller 403 is displaced. Therefore, even when the first cleaning blade 411 and the second cleaning blade 421 are used for the secondary transfer belt 406, the contact state between the first cleaning blade 411 and the second cleaning blade 421 and the secondary transfer belt 406 remains. It is stable and can prevent poor cleaning.

That is, the belt device 40 according to the present embodiment is a belt unit (secondary transfer unit 41) having a belt member (secondary transfer belt 406) wound around a plurality of rotating bodies 401, 402, 404 including a tension roller 403. )When,
With the first cleaning unit 410 which has the first cleaning member 411 for cleaning the belt member (secondary transfer belt 406) and is supported by the belt unit (secondary transfer unit 41) so as to be integrally movable with the tension roller 403. ,
A second cleaning unit 420 which has a second cleaning member 421 for cleaning the belt member (secondary transfer belt 406) and is supported by the belt unit (secondary transfer unit 41) at a position different from that of the tension roller 403. Be prepared.

Therefore, since the first cleaning unit 410 can move integrally with the tension roller 403, even if the position of the tension roller 403 fluctuates, the first cleaning member 411 and the belt member (secondary transfer belt 406) come into contact with each other. The condition is stable. Further, since the second cleaning unit 420 is supported by the belt unit (secondary transfer unit 41) at a position different from that of the tension roller 403, even if the position of the tension roller 403 fluctuates, the second cleaning member 421 and the belt The contact state with the member (secondary transfer belt 406) is stable. As a result, poor cleaning can be prevented.

A configuration is also conceivable in which one cleaning unit includes both a first cleaning member and a second cleaning member, and this unit is supported by a belt unit so that it can move integrally with the tension roller. In this case, The cleaning unit becomes large.
Further, it is also conceivable that one cleaning unit includes both the first cleaning member 411 and the second cleaning member 421, and this unit is supported by the belt unit (secondary transfer unit 41) at a position different from that of the tension roller 403. However, in this case, a large space for accommodating the cleaning unit is required at a position different from that of the tension roller 403, and the entire belt device becomes large. According to the present invention, it is possible to prevent cleaning defects while reducing the size of the device.

Next, a specific structure of the first cleaning unit 410 and the second cleaning unit 420 will be described.
FIG. 8 is a plan view schematically showing the configuration of the first cleaning unit 410, FIG. 9 is a perspective view illustrating the configuration of the first cleaning unit, and FIG. 10 is a support on one end 403Aa side of the shaft portion 403A of the tension roller 403. An enlarged perspective view for explaining the structure, FIG. 11 is a view for explaining the configuration of a fixed portion between the shaft portion 403A of the tension roller 403 and the first cleaning unit 410, and FIG. 12 is a view showing the other end 403Ab side of the shaft portion 403A of the tension roller 403. It is an enlarged perspective view explaining the support structure of.
In the present embodiment, the first cleaning unit 410 is fixed to the shaft portion 403A of the tension roller 403, and the tension roller 403 and the first cleaning unit 410 can be integrally moved with the displacement of the shaft portion 403A .

As shown in FIGS. 8 and 9, the first cleaning unit 410 includes a first cleaning blade 411 and a pair of first unit side plates 412A and 412B which are frames located in the axial direction of the tension roller 403 indicated by reference numeral W. , A first blade holder 414 for mounting the first cleaning blade 411 on the side plates 412A and 412B of the first unit is provided. The first cleaning blade 411 is a plate-shaped member having elasticity extending in the axial direction W, and has a first portion so that one end 411a protrudes from an end portion of a metal first blade holder 414 extending in the axial direction W. 1 It is fixed to the blade holder 414 with a fastening member such as a screw. The first blade holder 414 is a side plate of the first unit so that the edge of one end 411a faces the tension roller 403 over the entire axial direction and abuts on the surface 406b of the secondary transfer belt 406, preferably in pressure contact. It is attached to 412A and 412B. In the present embodiment, the first blade holder 414 is swingably supported by the first unit side plates 412A and 412B made of sheet metal around the fulcrum portions 419A and 419B, and as shown in FIG. The contact angle (opposing angle) θ1 with respect to the belt 406 (tension roller 403) can be adjusted. Note that FIG. 10 shows only the configuration on the side plate 412A side of the first unit.

As shown in FIGS. 9, 10 and 11, the first unit side plates 412A and 412B are provided with mounting portions 412Ab and 412Bb bent in the axial direction W of the shaft portion 403A. As shown in FIG. 11 , the mounting portion 412Ab is formed on the first unit side plate 412A so as to polymerize on the first unit side plate 412A. The mounting portion 412Bb side has the same configuration. Holes for inserting bolts 460A and 460B, which are fastening members, are formed in the mounting portions 412Ab and 412Bb , respectively. Screw holes are formed in the ends 403Aa and 403Ab of the shaft portion 403A in the diameter direction orthogonal to the axial direction W, respectively. The first cleaning unit 410 is integrated with the tension roller 403 by screwing the bolts 460A and 460B, which are mounted and inserted into the mounting portions 412Ab and 412Bb, into the screw holes, respectively. Therefore, the positional accuracy between the tension roller 403 and the first cleaning blade 411 is improved. As shown in FIG. 11, when the washer 460Aa of the head portion of the bolt 460A is mounted on the mounting portion 412Ab and fastened to the shaft portion 403A , it overlaps (polymerizes) with the first unit side plate 412A on the mounting portion 412Ab. Therefore, the tightening torque at the time of fastening is positioned so as to be applied to the side plate 412A of the first unit. When the washer 460Ba of the head portion of the bolt 460B is also mounted on the mounting portion 412Bb and fastened to the shaft portion 403Ab, it overlaps (polymerizes) with the first unit side plate 412B on the mounting portion 412Bb and is tightened at the time of fastening. The torque is positioned so as to be applied to the side plate 412B of the first unit.

As shown in FIG. 8, notches 415A and 415B are formed on the end faces 412Aa and 412Ba of the first unit side plates 412A and 412B at positions facing each other. As shown in FIG. 12, an annular groove 417 is formed in the end portion 403Ab of the shaft portion 403A of the tension roller 403. The width t1 of the annular groove 417 in the axial direction is formed to be slightly larger than the plate thickness t2 of the first unit side plate 412B in the cut portion 415B, so that the groove 417 can be inserted into the cut portion 415B. In the tension roller 403, the ends 403Aa and 403Ab of the shaft portion 403A are inserted into the cut portions 415A and 415B as shown in FIG. 8, so that the cut portion 415B fits into the annular groove 417, so that the axial direction W Positioning is done.

That is, the first cleaning unit 410 supports the ends 403Aa and 403Ab of the shaft portion 403A of the tension roller 403 with the cut portions 415A and 415B of the side plates 412A and 412B of the first unit, so that the entire unit becomes a fulcrum portion 419A and 419B. It becomes swingable with respect to the tension roller 403 around the center. However, since the position of the first cleaning unit 410 cannot be determined by this, in the present embodiment, the ends of the first unit side plates 412A and 412B and the shaft portion 403A of the tension roller 403 are used by using bolts 460A and 460B as fastening members. The first cleaning unit 410 and the tension roller 403 are integrated by fastening and fixing the 403Aa and 403Ab.
The first cleaning unit 410 integrated with the tension roller 403 is mounted on the first unit side plates 412A and 412B of the secondary transfer unit 41, and the ends 403Aa and 403Ab of the shaft portion 403A are supported by the holders 408A and 408B, respectively. As a result, it is slidably supported with respect to the first unit side plates 412A and 412B.

As described above, in the present embodiment, since the mounting portions 412Ab and 412Bb are formed so as to overlap with the first unit side plates 412A and 412B, the bending rigidity is increased. Further, when the bolts 460A and 460B attached to the attachment portions 412Ab and 412Bb are also fastened to the end portions 403Aa and 403Ab of the shaft portion 403A, the seat surfaces 412Aa and 412Ba are polymerized on the first unit side plates 412A and 412B. Therefore, when fixing the first cleaning unit 410 with the bolts 460A and 460B to the ends 403Aa and 403Ab of the shaft portion 403A of the tension roller 403, even if the bolts 460A and 460B are tightened too much, the mounting portion 412Ab, There is little deflection of 412Bb. As a result, the deflection of the shaft portion 403A of the tension roller 403 can be suppressed, the contact state between the first cleaning blade 411 and the second cleaning blade 421 and the secondary transfer belt 406 is stabilized, and cleaning defects are prevented. Can be done.

In the present embodiment, the first cleaning member 411 comes into contact with the tension roller 403 via the belt member (secondary transfer belt 406). Therefore, the contact state between the first cleaning member 411 and the belt member secondary transfer belt 406) is more stable, and cleaning defects can be prevented.

Next, the second cleaning unit 420 will be described. FIG. 13 is a plan view schematically showing the configuration of the second cleaning unit 420, FIG. 14 is a perspective view illustrating the configuration of the main part of the second cleaning unit 420, and FIG. 15 shows the overall configuration of the second cleaning unit 420. A perspective view, FIG. 16 is an external view explaining the mounting structure of the second cleaning unit 420, FIG. 17 is a partially enlarged perspective view explaining the mounting structure of the second cleaning unit 420, and FIG. 18 shows the second cleaning unit 420 and the second. It is a figure explaining the positional relationship of the blade facing roller 404.
In the present embodiment, as shown in FIGS. 13 and 14, the second cleaning unit 420 has a second cleaning blade 421, a unit frame 422, and a second cleaning blade 421 for mounting the second cleaning blade 421 on the unit frame 422. It includes a blade holder 423. The unit frame 422 extends in the axial direction W, and second unit side plates 422A and 422B are formed at both ends thereof. The second cleaning blade 421 is a plate-shaped member having elasticity extending in the axial direction W, and has a second cleaning blade so that one end 421a protrudes from the end of the metal second blade holder 423 extending in the axial direction W. 2 It is fixed to the blade holder 423 with a fastening member such as a screw. The second cleaning blade 421 is attached to the unit frame 422 at a constant angle via the second blade holder 423. The second cleaning unit 420 is configured as one unit by mounting the second cleaning blade 421 on the unit frame 422 via the second blade holder 423 .

The second cleaning unit 420 is attached to the side plates 409A and 409B. Positioning pins 424A and 425A are formed on the side plate 409A. Positioning pins 424B and 425B are formed on the side plate 409B. Positioning holes 426A and 427B for inserting positioning pins 424A and 425A are formed in the side plate 422A of the second unit. The second unit side plate 422B is formed with positioning holes 426B and 427B for inserting the positioning pins 424B and 425B.
As shown in FIG. 15, the second cleaning unit 420 inserts the positioning pins 424A and 425A of the side plate 409A into the positioning holes 426A and 427B formed in the side plate 422A of the second unit, and inserts the positioning pins 424B and 425B of the side plate 409BB. By inserting it into the positioning holes 426B and 427B of the side plate 422B of the second unit, it is fixed to the side plates 409A and 409B as shown in FIGS. 17 and 18. One end 421a of the second cleaning blade 421 has an abutting angle (opposing angle) with respect to the secondary transfer belt 406 (second blade facing roller 404) with the second cleaning unit 420 fixed to the side plates 409A and 409B. The contact is made with θ2.

As described above, the second blade facing roller 404 and the second cleaning blade 421 have the same housing, and the side plates 409A are located at different positions from the first unit side plates 412A and 412B that hold the tension roller 403 and the first cleaning blade 411. , 409B.
Even when a plurality of cleaning members of the first cleaning blade 411 and the second cleaning blade 421 are used for the secondary transfer belt 406, the cleaning blade 411 facing the tension roller 403 moves integrally with the tension roller 403. Further, the second cleaning blade 421, which is different from the first cleaning blade 411 facing the tension roller 403, does not move even if the position of the tension roller 403 is displaced. Therefore, even when the first cleaning blade 411 and the second cleaning blade 421 are used for the secondary transfer belt 406, the contact state between the first cleaning blade 411 and the second cleaning blade 421 and the secondary transfer belt 406 remains. It is stable and can prevent poor cleaning.

In the present embodiment, the second cleaning member 421 comes into contact with one of the plurality of rotating bodies (second blade facing roller 404) via the belt member (secondary transfer belt 406).
Therefore, the contact state between the second cleaning member 421 and the belt member (secondary transfer belt 406) is more stable, and cleaning defects can be prevented.

That is, since the first cleaning blade 411 and second cleaning blade 421 is supported individually transfer device 40, the relative positions of the displacement by the secondary transfer belt 406 of the tension roller 403 is changed, the first cleaning Since the blade 411 (first cleaning unit 410) side moves together with the tension roller 403, the positional relationship is maintained. Further, in the second cleaning blade 421 (second cleaning unit 420 ) , even if the first cleaning blade 411 moves together with the tension roller 403, the second blade is on the side plates 409A and 409B different from the first cleaning blade 411. have opposing roller 404 is fixed, the second blade facing roller 404 and the same frame in which the side plates 409A, because it is fixed to 409B, solid a constant of the second blade facing roller 404 positional relationship between the second cleaning blade 421 It is maintained regardless of movement of the tape down and Deployment roller 403.
Therefore, even when a plurality of blade-shaped cleaning members are brought into contact with the secondary transfer belt 406, which is a belt-shaped transfer member whose position is displaced, both cleaning members and the belt-shaped cleaning member are arranged. The contact state of the belt is stable, and cleaning defects can be eliminated (cleaning defects can be prevented).

Further, in the present embodiment, a space where the transfer residual toner and paper dust scraped off by the second cleaning blade 421 fall and accumulate below the contact portion between the second cleaning blade 421 and the secondary transfer belt 406. A unit 424 (see FIG. 6) is provided. In this embodiment, the space portion 424 is formed in the units frame 422, the inside as in the first cleaning unit 410, not the waste toner conveying screw 452 provided as a collection member. This is because the transfer residual toner and the paper dust are mainly removed by the first cleaning blade 411 and the paper dust removing brush 43, so that the amount of the transfer residual toner and the paper dust deposited in the space 424 is small. Therefore, the second cleaning unit 420 does not need to consider the connection with the waste toner transfer screw 452 and the waste toner tank, and the replaceability of the unit can be improved. Further, the absence of the waste toner transport screw 452 leads to securing an extra space, and the replaceability is good when the life of the second cleaning blade 421 is reached.

In the present embodiment, the upper part of the second cleaning unit 420 is covered with the upstream side transport guide member 46 as shown in FIG. That is, an upstream transport guide member 46 is mounted on the unit frame 422 so as to cover at least the space portion 424 on the upper portion of the unit frame 422. Therefore, the upstream transfer guide member 46 functions as a cover member for the space portion 424, and the toner and paper dust accumulated in the space portion 424 can be prevented from scattering.

As shown in FIG. 4, the second cleaning unit 420 is arranged on the downstream side, here, above the lubricating brush 441. More specifically, the lower surface 424D , which is a part of the unit frame 422, is formed so as to follow the shape of the upper surface 42a on the cleaning portion 42 side. That is, among the plurality of cleaning units, the second cleaning unit 420, which is one cleaning unit, constitutes a cover portion that covers the first cleaning unit 410, which is another cleaning unit.
Therefore, the unit frame 422 functions as a cover member, and the leakage of toner and paper dust from the joint 428 between the second cleaning unit 420 and the cleaning unit 42 is suppressed to prevent the toner and paper dust from scattering. Can be prevented. A part of the first cleaning unit 410 may form a cover portion that covers the second cleaning unit 420.

(Second Embodiment)
A second embodiment will be described with reference to FIGS. 19 to 24.
In this embodiment, the configuration of the first embodiment includes a contact / detachment means 470 for moving the secondary transfer unit 41 in a direction in which the secondary transfer unit 41 is brought close to and separated from the intermediate transfer belt 31 which is an intermediate transfer body, and a secondary transfer nip N2. The nip pressure adjusting means 480 for adjusting the nip pressure is added.
As shown in FIGS. 19 and 20, the transfer device 40 includes a frame 49 that is swingably mounted on the printer body 100A in a direction that is swingably separated from the intermediate transfer belt 31 around the swing center axis 48. There is. The secondary transfer unit 41 described above is mounted on the frame 49, and an urging force F from the nip pressure adjusting means 480 toward the intermediate transfer belt 31 acts on the frame 49. The description of the intermediate transfer belt 31 is omitted in FIGS. 19 and 20 .
The contact / detachment means 470 is a rotation provided on the shafts 33A of the secondary transfer back surface roller 33 and the contact / detachment cams 471A and 471B and the contact / detachment cams 471A and 471B provided on the shaft 405A of the secondary transfer roller 405. The rollers 472A and 472B and the contact / detachment motor 473 as a drive source for rotationally driving the contact / detachment cams 471A and 471B are provided.

The contact / detachment cams 471A and 471B are composed of eccentric cams fixed to both ends of the shaft 33A. The contact / detachment cams 471A and 471B are formed in the same cam profile and are fixed to the shaft 33A at the same angle (phase). In the contact / detachment cams 471A and 471B, the position where the distance between the peripheral surface of each cam 471A and 471B and the shaft 33A is the longest is set as the top dead center 471A1, 471B1 , and the distance between the peripheral surface of each cam 471A and 471B and the shaft 33A. The position where is closest to is the top dead center 471A2, 471B2.
A pulley 474 is fixed to the end of the shaft 33A located outside the contact / detachment cam 471A in the axial direction. A drive belt 476 is wound around the pulley 474 with a drive pulley 475 provided on the drive shaft 473a of the contact / detachment motor. A cam position sensor 477 as a cam position detecting means for detecting the positions of the contact / detachment cams 471A and 471B by detecting the rotation angle of the pulley 474 is arranged around the pulley 474.

In such a configuration of the contact / detachment means 470, when the contact / detachment motor 473 is operated, the rotational driving force of the contact / detachment motor 473 is transmitted from the pulley 474 to the shaft 33A via the drive pulley 475 and the drive belt 476. , The contact / detachment cams 471A and 471B rotate. The rotation angles (rotation positions) of the contact / detachment cams 471A and 471B are detected by the cam position sensor 477.
FIG. 21 shows the contact / detachment operation of the secondary transfer unit 41 by the operation of the attachment / detachment means 470. FIG. 21 (a) shows a separated state in which the intermediate transfer belt 31 and the secondary transfer belt 406 are separated from each other, and FIG. 21 (b) shows a contact state in which the intermediate transfer belt 31 and the secondary transfer belt 406 are in contact with each other. Indicates the state. The contact state here is a pressurized state in which a nip pressure at which a toner image can be transferred is generated on the recording material P.
In the separated state between the intermediate transfer belt 31 and the secondary transfer belt 406 shown in FIG. 21A, the contact / detachment cams 471A and 471B rotate, and the rotary rollers 472A at the top dead centers 471A1 and 471B1 of the contact / detachment cams 471A and 471B. , 472B is reached, pushed downward in the figure against the urging force from the nip pressure adjusting means 480, and the frame 49 moves clockwise around the swing center axis 48.
In the contact state (pressure contact state) between the intermediate transfer belt 31 and the secondary transfer belt 406 shown in FIG. 21 (b), the contact / detachment cams 471A and 471B rotate, and the bottom dead center 471A2 of the contact / detachment cams 471A and 471B, This is achieved by the 471B2 reaching a position facing the rotating rollers 472A and 472B, and the frame 49 moving counterclockwise by the urging force from the nip pressure adjusting means 480 around the swing center axis 48. ..
The contact / disengagement operation by the contact / disengagement means 470 is executed within a short time between the first recording material P and the next recording material P. That is, at the time of printing in which the toner image is transferred to the recording material P, the contact / separation motor 473 is operated so as to press the rotary rollers 472A and 472B at the top dead centers 471A1 and 47B1 of the contact / separation cams 471A and 471B, and the first The contact / detachment motor 473 is operated so that the bottom dead centers 471A2 and 47B2 of the contact / detachment cams 471A and 471B come into contact with the rotary rollers 472A and 472B between the recording material P and the next recording material P, so-called paper. Therefore, it is preferable to use a stepping motor, which is a responsive motor, as the contact / separation motor 473 for connecting / detaching the secondary transfer unit 41.

As mainly shown in FIGS. 22 and 23, the nip pressure adjusting means 480 includes pressure arms 481A and 481B that can swing around the shaft 484, and pressure cams 482A and 482B provided on the cam shaft 485. The pressurizing arms 481A and 481B are provided with rotary rollers 483A and 483B that come into contact with the pressurizing cams 482A and 482B, and a pressurizing motor 486 as a drive source for rotationally driving the pressurizing cams 482A and 482B. ..

One end of the pressurizing arms 481A and 481B is fixed to the shaft 484 on the side of 481Aa and 481Ba, and the other ends 481Ab and 481Bb, which are swing ends, are arranged so as to abut from below on the frame 49. The pressure cams 482A and 482B are composed of eccentric cams fixed to both ends of the cam shaft 485. The pressure cams 482A and 482B are formed in the same cam profile and are fixed to the cam shaft 485 at the same angle (phase). The outer peripheral surfaces of the pressurized cams 482A and 482B are cam surfaces 482Aa and 482Ba. The cam surfaces 482Aa and 482Ba are curved in a direction that is temporarily separated from the cam shaft 485. The pressure arms of the pressurizing cams 482A and 482B are such that the pressing force increases as the distance between the cam surfaces 482Aa and 482Ba and the cam shaft 485 increases, and the pressing force decreases as the distance from the cam shaft 485 decreases. The 481A and 481B are swung. The cam shaft 485 is configured so that the driving force of the pressurizing motor 486 is transmitted by a driving force transmitting unit composed of a belt, a pulley, and the like.
Rotating rollers 483A and 483B are arranged between one ends 481Aa and 481Ba and the other ends 481Ab and 481Bb of the pressurizing arms 481A and 481B. The rotating rollers 483A and 483B are always in contact with the cam surfaces 482Aa and 482Ba of the pressure cams 482A and 482B.
In such a configuration of the nip pressure adjusting means 480, when the pressurizing motor 486 is operated, the rotational driving force is transmitted to the cam shaft 485, and the pressurizing cams 482A and 482B are rotated to swing the pressurizing arms 481A and 481B. Move to adjust the nip pressure.

FIG. 24 shows a nip pressure adjusting operation by the operation of the nip pressure adjusting means 480. FIG. 24 (a) shows a reduced pressure state in which the secondary transfer unit 41 is retracted in the direction away from the intermediate transfer belt 31 to reduce the nip pressure at the secondary transfer nip N2, and FIG. 24 (b) shows the second. It shows an increased pressure state in which the nip pressure at the secondary transfer nip N2 is increased by moving the secondary transfer unit 41 in a direction closer to the intermediate transfer belt 31.
That is, when the pressure motor 486 is operated in the direction in which the distance between the cam surfaces 482Aa and 482Ba of the pressure cams 482A and 482B and the cam shaft 485 is shortened to rotate the pressure cams 482A and 482B, FIG. 24A shows. As shown in the above, the pressurizing arms 481A and 481B swing counterclockwise in the drawing via the rotating rollers 483A and 483B to move the frame 49 downward, and the nip pressure at the secondary transfer nip N2 is increased. Reduce the pressure. As shown in FIG. 24B, the pressure motor 486 is operated in the direction in which the distance between the cam surfaces 482Aa, 482Ba and the cam shaft 485 of the pressure cams 482A and 482B becomes longer to rotate the pressure cams 482A and 482B. Then, the pressurizing arms 481A and 481B swing clockwise in the drawing via the rotating rollers 483A and 483B to push up the frame 49 from below, and the nip pressure at the secondary transfer nip N2 is increased.

The nip pressure adjusting operation by the nip pressure adjusting means 480 can be performed, for example, depending on the type of recording material P. For example, when the recording paper P is a recording paper having abundant irregularities or a thin paper having a small basis weight, when these recording materials P are selected or detected, the pressurizing motor 486 is operated to operate the pressurizing arm 481A. , 481B can be swung to increase the nip pressure. When the recording paper P is a thick paper having a large basis weight, when the recording material P is selected or detected, the pressurizing motor 486 is operated to swing the pressurizing arms 481A and 481B to nip pressure. Can be depressurized. By adjusting the increase / decrease of the nip pressure by the nip pressure adjusting means 480 in this way, it is possible to correspond to various types of recording materials P.

By the way, the displacement of the tension roller 403 also changes due to a change in the external force on the secondary transfer belt 406. For example, if the secondary transfer unit 41 is provided with the contact / detachment means 470 and the nip pressure adjusting means 480 that displace the secondary transfer unit 41 in the direction of being close to and separated from the intermediate transfer belt 31, the secondary transfer unit 41 is provided. Since the force applied to the secondary transfer belt 406 is changed with the movement of the tension roller 403, the tension roller 403 also follows the movement, which causes poor cleaning.
However, as described in the first embodiment, when the nip pressure related to the secondary transfer nip N2 fluctuates by connecting and integrating the first cleaning blade 411 and the shaft portion 403A of the tension roller 403. However, since the first cleaning blade 411 moves integrally with the tension roller 403, the positional relationship between the two is maintained. Further, since the second cleaning blade 421 is supported by a frame different from that of the first cleaning blade 411, even if the positions of the tension roller 403 and the secondary transfer belt 406 are displaced, the second blade facing roller 404 and the second are second. The positional relationship with the cleaning blade 421 can be secured. Therefore, even when a plurality of cleaning members are used for the belt-shaped transfer member as the cleaning target, a stable contact (pressure contact) state between both cleaning members and the secondary transfer belt 406 can be ensured. Cleaning defects can be suppressed, preferably prevented.

In the transfer device 40, a part of the first cleaning unit 410 is used to form a space 451 so that foreign matter such as toner and paper dust that has been cleaned can be deposited. Further, in the first cleaning unit 410, since the amount to be cleaned is large and a large amount of foreign matter is deposited in the space 45, the waste toner transport screw 452 is arranged to transport the deposits in the space 45 to the outside.
On the other hand, in the second cleaning unit 420, the space portion 424 is formed by using the unit frame 422 which is a part thereof, but the waste toner transfer screw 452 is not arranged because the cleaning amount is small. Therefore, since it is not necessary to consider the connection with the waste toner tank, the box constituting the space portion 424 serving as the collection portion may be detachably arranged with respect to the second cleaning unit 420. With such a configuration, the space portion 424 can be removed separately from the transfer device 40, which is preferable because it is easy to use.

In the configuration including variable nip pressure + a plurality of cleaning members as described in the second embodiment , a speed difference is provided between the secondary transfer belt 406 and the elastic intermediate transfer belt 31 in consideration of image transferability. I have it. In general, the secondary transfer belt 406 is made slower than the intermediate transfer belt 31 and rubbed during transfer with the secondary transfer nip N2 to stabilize the image. Therefore, when the recording material P is paper, paper dust is likely to be generated, and a gap is created by the paper dust being caught between the first cleaning blade 411 and the secondary transfer belt 406, and the toner escapes through the gap. It may end up. However, even in such a configuration, not only the contact state between the first cleaning blade 411 and the secondary transfer belt 406 but also the contact state between the second cleaning blade 421 and the secondary transfer belt 406 is stabilized. It is possible to prevent poor cleaning.

In the above embodiment, since the second cleaning blade 421 is arranged on the downstream side of the lubrication brush 441, which is a lubrication coating member, the state of the foreign matter that has passed through the first cleaning blade 411 is in contact with the lubrication brush 441. By passing through the portion, the state becomes different from that when passing through the first cleaning blade 411. Therefore, the cleaning performance of the second cleaning blade 421 can be improved.
When paper dust or toner adheres to the lubricant 442, the amount of the lubricant 442 scraped by the lubricant brush 441 may vary, depending on the configuration of the device, the type of toner used, and the amount of paper dust generated. It is preferable that the first cleaning blade 411 and the second cleaning blade 421 are arranged side by side in the moving direction of the secondary transfer belt 406, and the lubricant application portion 44 is arranged on the downstream side of the second cleaning blade 421. That is, the order in which the first cleaning blade 411 and the second cleaning blade 421, which are the plurality of cleaning members, are arranged is not limited to the configurations of the first and second embodiments.

When the trajectory of the secondary transfer belt 406 moves as shown in FIGS. 7 (a) and 7 (b) due to the external force (nip pressure, nip width, etc.) applied to the secondary transfer belt 406 and the displacement of the tension roller 403, Not only is the crushing method of the seal member indicated by reference numeral S1 in FIG. 4 changed, but also the positional relationship between the second cleaning blade 421 and the secondary transfer belt 406 may be displaced.
Therefore, one end 421a of the second cleaning blade 421 faces the second blade facing roller 404 even when the tension roller 403 is displaced from the minimum value to the maximum value, and the contact state with the secondary transfer belt 406 is maintained. It is supported by the unit frame 422 so as to abut (press contact) with the secondary transfer belt 406 at an angle and position. That is, the second cleaning blade 421 is arranged so as to be in contact with the secondary transfer belt 406 within the trajectory fluctuation range of the secondary transfer belt 406 due to the displacement of the tension roller 403. That is, even if the tension roller 403 is displaced in the tension applying direction C, the second cleaning blade 421 has one end 421a of the second cleaning blade 421 within the winding range of the secondary transfer belt 406 and the second blade facing roller 404. Are arranged so that they are in contact with each other. By locating one end 421a of the second cleaning blade 421 in this way, more stable cleaning performance can be obtained and cleaning defects can be prevented.

The tension roller 403 described in the above embodiment is functionally movable in the diameter direction intersecting the axial direction W. Further, when the contact / detachment means 470 and the nip pressure adjusting means 480 are provided, the position of the tension roller 403 changes because the external force related to the secondary transfer belt 406 changes due to these operations. That is, the tension roller 403 is provided so as to be displaceable in the direction opposite to the tension applying direction C depending on the conditions.
Conditions (factors) for displacement of the tension roller 403 include a change in the peripheral length (expansion and contraction length) of the secondary transfer belt 406 due to the nip pressure, the material of the secondary transfer belt 403, and the environment such as temperature and humidity.
Therefore, the movable range of the tension roller 403 described in the above embodiment in the diameter direction (tension applying direction C) is defined.
The fluctuation range of the nip pressure by the nip pressure adjusting means 480 is a minimum pressure of 70 N and a maximum pressure of 300 N.
The material of the secondary transfer belt 406 is made of polyimide.
The temperature and humidity conditions are 10 ° C. and 15% RH to 30 ° C. and 80% RH.
Under these conditions, the displacement amount of the tension roller 403 when the inner peripheral length of the secondary transfer belt 406 changes is in the range of 2 to 3 mm.
With this amount of displacement of the tension roller 403, good contact between the second cleaning blade 421 and the secondary transfer belt 406 can be maintained.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and the present invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.
For example, as an image forming apparatus, a transfer unit (secondary transfer nip N) for transporting the recording material P in the horizontal direction has been described, but the transfer unit moves the recording material P upward, downward, diagonally upward or diagonally. The present invention can also be applied to an image forming apparatus having a configuration in which the image is conveyed downward.
The image forming apparatus may be not a printer but a copying machine, a facsimile alone, or a multifunction device having at least two functions of a copying machine, a printer, a facsimile, and a scanner.
As a belt device which is one of the present inventions, a transfer device 40 provided with a secondary transfer belt 406 abutting on the intermediate transfer belt 31 has been exemplified, but as a form of the belt device, a transfer device 40 provided with a secondary transfer belt 40 has been exemplified. It is not limited. For example, it is a transfer unit in which an intermediate transfer belt 31 which is a transfer member composed of a belt member contacts photoconductors 2Y, 2M, 2C, and 2K which are image carriers to form a transfer nip (primary transfer nip) N1. The configuration of the above-described embodiment may be applied to the intermediate transfer unit 30.
The scope of application of the belt device according to the present invention is not limited to the image forming device using toner, and in terms of cleaning paper dust, ink capable of transporting the recording material P using the belt member is used. It can be applied to the field of image formation by using it.
Focusing on the point of cleaning the belt device, the scope of application of the belt device according to the present invention is not limited to the field of image formation, and a plurality of cleanings are applied to the belt member to which tension is applied by the tension roller. It can be applied to the field of using a belt device with which members come into contact.
In the above embodiment, the first cleaning blade 411 and the second cleaning blade 421 are shown as the plurality of cleaning members, but the cleaning members are not limited to the blades, and at least one is a blade and the other is a cleaning roller. It may be in the form of.
Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and the present invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.

2Y, 2M, 2C, 2K image carrier 31 Transfer member (intermediate transfer member)
30 Transfer unit 40 Belt device 41 Belt unit (secondary transfer unit)
401, 402, 405 Multiple rotating bodies 403 Tension roller (rotating body)
403A Shaft 404 Rotating body 406 Belt member, secondary transfer member 411 First cleaning member (cleaning blade)
412A, 412B Frame 421 2nd cleaning member (cleaning blade)
410 1st cleaning unit 420 2nd cleaning unit 452 Recovery member 412Ab, 412Bb Mounting part 460A, 460B Fastening member W Axial direction N1 Transfer nip N2 Secondary transfer nip 470 Contact / detachment means 480 Nip pressure adjusting means

JP-A-2010-164820

Claims (15)

A belt unit having a plurality of belt wound around member to the rotating member comprising a tension roller,
The tension roller and the contact via the belt member has a first cleaning member for cleaning said belt member, a first cleaning unit supported before Symbol belt unit,
Through said belt member and the rotary member abuts different from the tension roller, a second cleaning member for cleaning said belt member, and a second cleaning unit supported before Symbol belt unit,
The first side plate supporting the first cleaning unit and the tension roller are connected, and the first cleaning unit can be displaced according to the displacement of the tension roller.
A belt device in which the second cleaning unit is supported by a second side plate different from the first side plate, and the second cleaning unit is not displaced even if the tension roller is displaced . In the belt device according to claim 1,
A belt device having a fastening member that connects the first side plate and the shaft portion of the tension roller and fastens the first side plate and the tension roller . In the belt device according to claim 2,
A belt device characterized in that a mounting portion bent in the axial direction of the shaft portion is provided on the first side plate, and the fastening member is mounted on the mounting portion . In the belt device according to any one of claims 1 to 3.
Belt device wherein the first cleaning unit which includes a collecting member for collecting the foreign matter cleaned before Symbol first cleaning member. In the belt device according to claim 4,
Belt and wherein the second cleaning unit is not provided with the pre-Symbol recovery member. In the belt device according to any one of claims 1 to 5,
Belt apparatus, wherein at least one of the first cleaning member or the second cleaning member is constituted by a click leaning blade. In the belt device according to any one of claims 1 to 6.
Belt and wherein the part constituting the cover portion for covering the front Stories second cleaning unit of the first cleaning unit. In the belt device according to any one of claims 1 to 7.
The tension roller be supported by the shaft portion to the frame of the prior SL first cleaning unit, and a mounting portion provided on said frame so as to overlap extend in the axial direction and the previous SL frame of the shaft portion, belt device and having a fastening member for fastening the Kijiku portion before being mounted to the mounting portion so as to overlap with the frame in the direction intersecting with the axial direction. In the belt device according to any one of claims 1 to 8.
The tension roller is provided displaceably in the tensioning direction in response to conditions, the second cleaning member is equivalent to the prior Symbol belt member in an orbital fluctuation range of the belt member due to the displacement of the front Symbol tension roller A belt device characterized by being arranged in contact with each other. In the belt device according to claim 9,
The belt device is characterized in that the condition is the expansion and contraction length of the belt member due to temperature and humidity. And transferring member comprising a belt member is a transfer apparatus having a transfer unit to form a transfer nip in contact with the image bearing member, the transfer unit according to any one of請Motomeko 1 to 10 A transfer device characterized by being a belt device. A transfer apparatus having a secondary transfer unit that secondary transfer member comprising a belt member forms a contact with the secondary transfer nip to an intermediate transfer member, to the secondary transfer unit請Motomeko 1 to 10 A transfer device according to any one of the above. A transfer apparatus having a secondary transfer unit that the secondary transfer member which is composed of the belt member is in contact with the intermediate transfer member to form a secondary transfer nip, the secondary transfer unit is described in請Motomeko 9 The belt device is provided with a contact / detachment means for moving the secondary transfer unit in a direction in which the secondary transfer unit is brought close to and separated from the intermediate transfer body. A transfer device characterized by a stretchable length of . The transfer device including a secondary transfer unit in which a secondary transfer member composed of a belt member contacts an intermediate transfer body to form a secondary transfer nip, wherein the secondary transfer unit is described in claim 9. It is a belt device, has a nip pressure adjusting means for adjusting the nip pressure applied to the secondary transfer nip, and the condition is the expansion and contraction length of the secondary transfer member by the nip pressure adjusting operation of the nip pressure adjusting means. A transfer device characterized by . An image forming apparatus including the transfer apparatus according to any one of claims 11 to 14.

Images