JP2021039195A - Belt conveying device and image forming apparatus including the same - Google Patents

Abstract

To provide a belt conveying device that can prevent deviation of an endless conveying belt with a simple configuration, and an image forming apparatus including the same.SOLUTION: A belt conveying device comprises: an endless conveying belt; a plurality of belt support rollers; a roller support frame; a brush roller; and a voltage application unit. The belt support rollers stretch the conveying belt. The roller support frame rotatably supports the belt support rollers. The brush roller rotates in a counter direction with respect to the direction of movement of the conveying belt while in contact with an outer peripheral surface of the conveying belt. The voltage application unit applies voltage to the brush roller. The brush roller includes a rotation shaft, and brush bristles that are provided uniformly at a predetermined density over the substantially entire area in the axial direction on an outer peripheral surface of the rotation shaft. The directions of mesh of the brush bristles are inclined in the opposite directions to each other toward both end sides in the axial direction with the center in the axial direction of the rotation shaft as a symmetry axis.SELECTED DRAWING: Figure 8

Description

The present invention is mounted on an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction device thereof, and conveys a recording medium such as paper or a toner image on a conveying belt in a state of being electrostatically adsorbed on the conveying belt. It relates to an image forming apparatus provided with.

Conventionally, an endless intermediate transfer belt that is rotated in a predetermined direction and a plurality of image forming portions provided along the intermediate transfer belt are provided, and each image forming portion puts a toner image of each color on the intermediate transfer belt. There is known an intermediate transfer type image forming apparatus that sequentially superimposes and transfers the primary transfer and then transfers the secondary transfer onto a recording medium. In such an intermediate transfer type image forming apparatus, a belt cleaning apparatus provided with a brush roller that mechanically and electrically recovers the toner remaining on the surface of the intermediate transfer belt is used.

In the belt cleaning device as described above, when performing a development calibration that detects the density of the patch image formed on the intermediate transfer belt and adjusts the development conditions, it is usual to reliably clean the patch image. The brush roller in a state where a cleaning voltage higher than that at the time of printing is applied is in contact with the intermediate transfer belt. Therefore, a large frictional force is generated between the intermediate transfer belt and the brush roller, and the deviation of the frictional force promotes the deviation (meandering) of the intermediate transfer belt, and the intermediate transfer unit including the intermediate transfer belt is damaged. There was a risk of problems.

Conventionally, as measures against deviation of the conveyor belt, a deviation control member has been attached to the inner peripheral surface of the belt, a belt deviation prevention ring has been installed at the end of the roller shaft, and an alignment control mechanism has been installed on the belt support roller. It has been broken. However, when a strong buckling force is generated, it is easy for the buckling control member to peel off and ride on the belt support roller when the measures are taken by attaching the buckling control member, and the belt side end is likely to occur when the belt stop ring is installed. Damage due to buckling is likely to occur. In addition, there are problems such as installation space and cost increase in the measures for installing the alignment control mechanism.

Therefore, as a method of suppressing the deviation of the transport belt with a simple configuration, Patent Document 1 describes the rotation direction of the rollers symmetrically with respect to the axial center on the outer peripheral surfaces of either one or both of the driving roller and the driven roller. A plurality of parallel grooves inclined from the center in the upstream direction toward the downstream end in the rotation direction are provided, and the rotation of the roller pulls the endless belt from the center side in the roller direction toward both ends in the width direction. A belt transfer device that generates a force that is opposite to each other and is symmetrical in the width direction is disclosed.

Further, in Patent Document 2, a dust-removing / width-out roll composed of a cylindrical roll core and brush bristles attached to the surface of the roll core is provided in the traveling path of the film, and the dust-removing / width-out roll is provided in the traveling direction of the film. A roll drive device for a thin film body having both dust removal processing and width adjustment functions by rotating the film in the same direction as the film and at a peripheral speed faster than the running speed of the film is disclosed.

Japanese Unexamined Patent Publication No. 2005-344750 Japanese Unexamined Patent Publication No. 10-29746

However, in the method of Patent Document 1, grooves or polishing marks are formed on the surface of the roller on which the transport belt is stretched, and it is necessary to form the grooves or polishing marks deeply in order to obtain a sufficient effect of suppressing bias. There is a problem that it takes time and cost to process the roller.

Further, in the method of Patent Document 2, the tension in the width direction of the film is generated by the elastic deformation of the brush bristles to perform the width adjustment. Therefore, although it is possible to widen a thin film such as a film, it is difficult to widen a transport belt which is thicker and heavier than a film. Further, the dust removal / width-out roll of Patent Document 2 is applied to a brush roller for cleaning an intermediate transfer belt because a portion where brush bristles are present and a portion where brush bristles are not present are alternately formed in a strip shape in the axial direction of the roll core. In this case, it was difficult to reliably remove the toner remaining on the belt surface.

In view of the above problems, it is an object of the present invention to provide a belt transfer device capable of suppressing the deviation of an endless transfer belt with a simple configuration and an image forming device provided with the belt transfer device.

In order to achieve the above object, the first configuration of the present invention is a belt transfer device including an endless transfer belt, a plurality of belt support rollers, a roller support frame, a brush roller, and a voltage application unit. Is. The belt support roller stretches the transport belt. The roller support frame rotatably supports the belt support rollers. The brush roller rotates in the counter direction with respect to the rotation direction of the transfer belt in a state of being in contact with the outer peripheral surface of the transfer belt. The voltage application unit applies a voltage to the brush roller. The brush roller includes a rotating shaft and brush bristles uniformly attached to the outer peripheral surface of the rotating shaft at a predetermined density over substantially the entire axial direction. The eye direction of the brush bristles is inclined in opposite directions toward both end sides in the axial direction with the center of the axial direction of the rotation axis as the axis of symmetry.

According to the first configuration of the present invention, when the transport belt is rotationally driven, the brush bristles are elastically deformed symmetrically with the center of the brush roller in the axial direction as the axis of symmetry. As a result, the electric attraction force acting between the brush bristles and the transport belt causes a force acting from the brush bristles to the transport belt in opposite directions and in the width direction. As a result, if the transport belt is biased even a little, the symmetrical force balance is lost, and the force that tries to return to the state before the bias occurs acts, so that the bias of the transport belt is effectively suppressed. be able to. In addition, since it is not necessary to attach a leaning regulation member to the inner peripheral surface of the conveyor belt or to arrange a belt locking ring at the axial end of the belt support roller, installation of a leaning regulating member or a belt locking ring is installed. There is no need to consider space, and the number of members and assembly man-hours can be reduced.

Schematic diagram showing the configuration of the image forming apparatus 100 on which the intermediate transfer unit 30 of the present invention is mounted. Partially enlarged view of the image forming portion P in FIG. Side sectional view of the intermediate transfer unit 30 mounted on the image forming apparatus 100. External perspective view of the intermediate transfer unit 30 External perspective view of the belt cleaning unit 19 attached to the intermediate transfer unit 30. Side sectional view showing the internal configuration of the belt cleaning unit 19. The figure which shows typically the connection path of a belt cleaning unit 19 and a high voltage power source 60. Side view of the fur brush 41 of the belt cleaning unit 19 as viewed from the radial direction (right side in FIG. 6). An enlarged view showing a contact state between the brush bristles 41b and the intermediate transfer belt 8 on one side (right side in FIG. 8) of the fur brush 41 in the axial direction. An enlarged view showing a contact state between the brush bristles 41b and the intermediate transfer belt 8 on the other side (left side in FIG. 8) of the fur brush 41 in the axial direction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing the configuration of an image forming apparatus 100 on which the intermediate transfer unit 30 of the present invention is mounted, and FIG. 2 is an enlarged view of the vicinity of the image forming portion Pa in FIG.

The image forming apparatus 100 shown in FIG. 1 is a so-called tandem color printer, and has the following configuration. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc and Pd are arranged in order from the upstream side in the transport direction (right side in FIG. 1). These image forming units Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and are cyan, magenta, and yellow, respectively, depending on each step of charging, exposure, development, and transfer. And black images are formed sequentially.

Photoreceptor drums 1a, 1b, 1c and 1d carrying visible images (toner images) of each color are arranged in these image forming portions Pa to Pd, and further by a belt drive motor (not shown). In FIG. 1, an intermediate transfer belt 8 that rotates in the clockwise direction is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photoconductor drums 1a to 1d are sequentially transferred onto the intermediate transfer belt 8 that moves while abutting on the photoconductor drums 1a to 1d, and then the recording medium is transferred by the secondary transfer roller 9. It is transferred at once on the transfer paper P as an example. Further, after being fixed on the transfer paper P in the fixing portion 13, the image forming apparatus 100 is discharged from the main body. The image forming process for each of the photoconductor drums 1a to 1d is executed while rotating the photoconductor drums 1a to 1d in the counterclockwise direction in FIG.

The transfer paper P on which the toner image is transferred is housed in the paper cassette 16 at the bottom of the image forming apparatus 100, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the resist roller pair 12b. .. A seamless (seamless) belt is mainly used for the intermediate transfer belt 8.

Next, the image forming units Pa to Pd will be described. Hereinafter, the image forming unit Pa will be described in detail, but since the image forming units Pb to Pd have basically the same configuration, the description thereof will be omitted. As shown in FIG. 2, a charging device 2a, a developing device 3a, and a cleaning device 7a are arranged around the photoconductor drum 1a along the drum rotation direction (counterclockwise direction in FIG. 1), and an intermediate transfer belt is provided. The primary transfer roller 6a is arranged with the 8 in between. Further, a belt cleaning unit 19 facing the tension roller 11 with the intermediate transfer belt 8 interposed therebetween is arranged on the upstream side of the photoconductor drum 1a in the rotation direction of the intermediate transfer belt 8.

Next, the image forming procedure in the image forming apparatus 100 will be described. When the start of image formation is input by the user, first, the surfaces of the photoconductor drums 1a to 1d are uniformly charged by the charging devices 2a to 2d. Next, the surfaces of the photoconductor drums 1a to 1d are irradiated with light by the beam light (laser light) emitted from the exposure apparatus 5, and an electrostatic latent image corresponding to the image signal is formed on the photoconductor drums 1a to 1d. The developing devices 3a to 3d are filled with a predetermined amount of toner of each color of cyan, magenta, yellow, and black, respectively. When the ratio of toner in the two-component developer filled in the developing devices 3a to 3d falls below the specified value due to the formation of the toner image described later, the toner containers 4a to 4d to the developing devices 3a to 3d are used. Toner is replenished. The toner in this developer is supplied onto the photoconductor drums 1a to 1d by the developing devices 3a to 3d, and is electrostatically adhered to the toners according to the electrostatic latent image formed by the exposure from the exposure device 5. A toner image is formed.

Then, an electric field is applied between the primary transfer rollers 6a to 6d and the photoconductor drums 1a to 1d at a predetermined transfer voltage by the primary transfer rollers 6a to 6d, and cyan, magenta, yellow, and cyan, magenta, yellow, and cyanide, magenta, and yellow on the photoconductor drums 1a to 1d are applied. The black toner image is primarily transferred onto the intermediate transfer belt 8. These four-color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. After that, the toner remaining on the surfaces of the photoconductor drums 1a to 1d is removed by the cleaning blade 32 and the rubbing roller 33 of the cleaning devices 7a to 7d in preparation for the subsequent formation of a new electrostatic latent image.

When the intermediate transfer belt 8 starts rotating clockwise with the rotation of the drive roller 10 by the belt drive motor (not shown), the transfer paper P is adjacent to the intermediate transfer belt 8 from the resist roller pair 12b at a predetermined timing. The full-color image is transferred to the secondary transfer roller 9 provided in the above. The transfer paper P on which the toner image is transferred is conveyed to the fixing portion 13. The toner remaining on the surface of the intermediate transfer belt 8 is removed by the belt cleaning unit 19.

The transfer paper P conveyed to the fixing portion 13 is heated and pressurized by the fixing roller pair 13a to fix the toner image on the surface of the transfer paper P, and a predetermined full-color image is formed. The transfer paper P on which the full-color image is formed is divided in the transport direction by the branching portions 14 branched in a plurality of directions. When an image is formed on only one side of the transfer paper P, the image is directly discharged to the discharge tray 17 by the discharge roller pair 15.

On the other hand, when forming an image on both sides of the transfer paper P, a part of the transfer paper P that has passed through the fixing portion 13 is once projected from the discharge roller pair 15 to the outside of the apparatus. After that, the transfer paper P is distributed to the reversing transfer path 18 at the branch portion 14 by rotating the discharge roller pair 15 in the reverse direction, and is re-conveyed to the secondary transfer roller 9 in a state where the image plane is inverted. Then, the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the surface on which the image of the transfer paper P is not formed, and is conveyed to the fixing portion 13 to fix the toner image. , Is discharged from the discharge roller pair 15 to the discharge tray 17.

FIG. 3 is a side sectional view of the intermediate transfer unit 30 mounted on the image forming apparatus 100. FIG. 4 is an external perspective view of the intermediate transfer unit 30. Note that FIG. 3 shows a state in which the intermediate transfer unit 30 is viewed from the back side of FIG. Further, FIG. 4 shows a state in which the inside can be seen by removing the cover of the belt cleaning unit 19.

As shown in FIGS. 3 and 4, the intermediate transfer unit 30 includes side frames 30a and 30b, primary transfer rollers 6a to 6d, an intermediate transfer belt 8, a drive roller 10, a tension roller 11, and a belt cleaning unit 19. And a pressing switching roller 34. The side frames 30a and 30b rotatably support the primary transfer rollers 6a to 6d, the drive roller 10, the tension roller 11, and the pressing switching roller 34. The intermediate transfer belt 8 is hung on the drive roller 10 on the downstream side and the tension roller 11 on the upstream side. The primary transfer rollers 6a to 6d come into contact with the photoconductor drums 1a to 1d via the intermediate transfer belt 8. The pressing switching roller 34 switches the pressing force of the primary transfer rollers 6a to 6d with respect to the photoconductor drums 1a to 1d. The belt cleaning unit 19 is arranged at a position facing the tension roller 11 and removes the toner remaining on the surface of the intermediate transfer belt 8.

FIG. 5 is an external perspective view of the belt cleaning unit 19 attached to the intermediate transfer unit 30. FIG. 6 is a side sectional view showing the internal configuration of the belt cleaning unit 19. FIG. 7 is a diagram schematically showing a connection path between the belt cleaning unit 19 and the high-voltage power supply 60. The belt cleaning unit 19 includes a fur brush 41, a recovery roller 43, a blade 45, and a transfer spiral 47 in the housing 40, and one end of the housing 40 is cleaned by the fur brush 41, the recovery roller 43, and the transfer spiral 47. A drive input gear train 48 for inputting a driving force from a drive motor (not shown) is arranged.

The fur brush 41 has a rotating shaft 41a and brush bristles 41b attached to the outer peripheral surface of the rotating shaft 41a. The brush bristles 41b are uniformly attached at a predetermined density over substantially the entire axial direction of the rotating shaft 41a. The fur brush 41 is arranged on the opening 40a side of the housing 40 so as to face the tension roller 11 via the intermediate transfer belt 8. The fur brush 41 rotates in the counter direction (counterclockwise direction in FIG. 6) with respect to the moving direction of the intermediate transfer belt 8, so that foreign matter such as toner and paper dust remaining on the intermediate transfer belt 8 (hereinafter, toner). Etc.) are scraped off. The brush bristles 41b of the fur brush 41 in contact with the recovery roller 43 are formed of conductive fibers having a resistance value of about 1 to 900 MΩ.

The recovery roller 43 collects the toner and the like adhering to the fur brush 41 by rotating in the direction opposite to that of the fur brush 41 (clockwise direction in FIG. 6) while contacting the surface of the fur brush 41. A high-voltage power supply 60 is connected to the rotating shaft 43a of the recovery roller 43, and a cleaning voltage having a polarity opposite to that of the toner (here, negative electrode) is applied when cleaning the intermediate transfer belt 8. Further, the tension roller 11 is grounded to the ground. As a result, the toner and the like remaining on the intermediate transfer belt 8 are electrically and mechanically recovered by the brush bristles 41b of the fur brush 41, and further electrically transferred to the recovery roller 43. Further, the back-charged (negatively charged) toner adhering to the brush bristles 41b of the fur brush 41 is discharged to the intermediate transfer belt 8.

The rotation shafts 41a and 43a of the fur brush 41 and the recovery roller 43 are rotatably supported by the housing 40. Further, the rotating shaft 41a of the fur brush 41 is urged by the compression spring 49 in the upper right direction (tension roller 11 direction) of FIG.

The blade 45 contacts the recovery roller 43 from the downstream side with respect to the rotation direction of the recovery roller 43 (counter direction with respect to the movement direction of the surface of the recovery roller 43), scrapes off the toner and the like collected by the recovery roller 43, and collects the toner. Clean the roller 43. The transport spiral 47 is arranged in the toner accommodating portion 40b of the housing 40, and transports the toner or the like scraped off from the recovery roller 43 by the blade 45 to a waste toner recovery container (not shown) outside the housing 40. ..

In the housing 40, the sheet members 50 are arranged to face each other over the entire longitudinal direction of the recovery roller 43 (the direction perpendicular to the paper surface of FIG. 6). The sheet member 50 is a sheet-like member made of, for example, polyurethane or the like, and is in contact with the recovery roller 43 with a predetermined contact pressure. It is necessary to set the contact pressure of the sheet member 50 so that the toner adhering to the recovery roller 43 is not scraped off and the toner or the like scraped off by the blade 45 does not go toward the recovery roller 43 side again.

A sealing member 51 made of an elastic material such as urethane foam or urethane sponge is arranged between both ends of the recovery roller 43 and the housing 40. As shown in FIG. 6, the seal member 51 is placed on the outer peripheral surface of the recovery roller 43 in the range upstream of the blade 45 and downstream of the seal member 51 with respect to the rotation direction of the recovery roller 43 (clockwise direction in FIG. 6). It extends in a side view arc shape so as to come into contact with each other, and is further arranged so as to extend downward along the seal member 51. The sealing member 51 is sandwiched between the recovery roller 43 and the housing 40 and compressed to prevent toner from entering the gap between the recovery roller 43 and the housing 40 and prevent toner from leaking to the outside of the housing 40. doing.

By the way, the offset (meandering) of the intermediate transfer belt may occur due to the offset of the frictional force generated between the intermediate transfer belt 8 and the fur brush 41. Once the offset occurs, the intermediate transfer belt 8 is offset to one side in the axial direction of the drive roller 10 and the tension roller 11, the intermediate transfer belt 8 is detached from the drive roller 10 and the tension roller 11, or the intermediate transfer belt 8 is displaced. There is a problem that the side edge comes into contact with members such as the side frames 30a and 30b and is damaged.

Therefore, in the present embodiment, the eye direction of the brush bristles 41b of the fur brush 41 is symmetrical with the central portion in the longitudinal direction as the axis of symmetry, and the leaning force (friction force) of the brush bristles 41b is balanced on both ends in the longitudinal direction. The offset of the intermediate transfer belt 8 is suppressed. The eye direction of the brush bristles 41b referred to in the present specification means the alignment direction of the brush bristles 41b in the circumferential direction of the fur brush 41.

FIG. 8 is a side view of the fur brush 41 of the belt cleaning unit 19 as viewed from the radial direction (right side of FIG. 6). As shown in FIG. 8, in the fur brush 41, the brush portion 41d in which the brush bristles 41b are planted on the belt-shaped base material 41c is the central portion in the axial direction of the rotation axis 41a and is orthogonal to the axis of the rotation axis 41a. With the straight line O as the axis of symmetry, the left side of the rotation axis 41a is spirally wound to the left and the right side to the right at a predetermined inclination angle θ.

FIG. 9 is an enlarged view showing a contact state between the brush bristles 41b and the intermediate transfer belt 8 on one side (left side in FIG. 8) of the fur brush 41 in the axial direction. On the left side of the fur brush 41 shown in FIG. 8, the eye direction of the brush bristles 41b is inclined to the left (outside in the belt width direction), so that the brush bristles 41b pass through the intermediate transfer belt 8 as shown in FIG. It is pressed by the tension roller 11 and elastically deforms so as to fall outward in the belt width direction (in the direction of the white arrow in FIG. 9).

Further, since the cleaning voltage is applied to the brush bristles 41b via the recovery roller 43, an electric attraction force acts between the brush bristles 41b and the intermediate transfer belt 8. Therefore, a force (hatching arrow in FIG. 9) that pulls the intermediate transfer belt 8 outward in the belt width direction is generated by the elastic deformation of the brush bristles 41b toward the outside in the belt width direction.

FIG. 10 is an enlarged view showing a contact state between the brush bristles 41b and the intermediate transfer belt 8 on the other side (right side of FIG. 8) of the fur brush 41 in the axial direction. On the right side of the fur brush 41 shown in FIG. 10, the eye direction of the brush bristles 41b is inclined to the right (outside in the belt width direction), so that the brush bristles 41b pass through the intermediate transfer belt 8 as shown in FIG. It is pressed by the tension roller 11 and elastically deforms so as to fall outward in the belt width direction (in the direction of the white arrow in FIG. 10).

Further, an electric suction force acts between the brush bristles 41b and the intermediate transfer belt 8. Therefore, a force (hatching arrow in FIG. 10) that pulls the intermediate transfer belt 8 outward in the belt width direction is generated by the elastic deformation of the brush bristles 41b toward the outside in the belt width direction.

According to the above principle, when the fur brush 41 is rotationally driven in a state of being in contact with the intermediate transfer belt 8, the brush bristles 41b are elastically deformed symmetrically with the straight line O as the axis of symmetry. As a result, a force symmetrical in the width direction is generated in opposite directions, such as pulling the intermediate transfer belt 8 from the central portion in the width direction of the intermediate transfer belt 8 toward both ends.

As a result, the intermediate transfer belt 8 comes into contact with the fur brush 41 in a state where tension is applied toward both ends in the width direction. Therefore, if any deviation occurs, the balance of the symmetrical displacement force is lost, and a force that tries to return to the state before the deviation occurs acts, so that the deviation of the intermediate transfer belt 8 can be effectively suppressed. Can be done.

Further, since it is not necessary to attach a leaning restricting member to the inner peripheral surface of the intermediate transfer belt 8 or to arrange a belt leaning prevention ring at the axial end of the drive roller 10 and the tension roller 11, the leaning regulating member or It is not necessary to consider the installation space of the belt stopper ring, and the number of members and the assembly man-hours can be reduced.

Further, in the conventional configuration in which a groove (polished grain) is provided on the outer peripheral surface of the belt support roller, in order to increase the effect of suppressing deviation, the depth of the groove is increased so that the inner peripheral surface of the belt facing the belt support roller is formed. It is necessary to make it easy for deformation to occur, and it takes time and effort to process the surface of the roller. In the present embodiment, the brush portion 41d in which the brush bristles 41b are planted on the belt-shaped base material 41c is wound in opposite directions from the center in the axial direction of the rotating shaft 41a toward both ends, so that the brush bristles 41b are in the eye direction. Is easier to process than the conventional configuration.

The inclination angle θ with respect to the straight line O (axis of symmetry) in the eye direction of the brush bristles 41b is not particularly limited, but when the eye direction of the brush bristles 41b is parallel to the belt traveling direction and perpendicular to the belt traveling direction (belt width). If it is parallel to the direction), the offset suppression effect cannot be obtained. As described above, it is necessary to generate a pulling force symmetrical in the width direction in opposite directions to pull the intermediate transfer belt 8, and in order to increase the elastic deformation of the brush bristles 41b in the width direction outward. It is preferable that the inclination angle θ of the brush bristles 41b in the eye direction with respect to the belt traveling direction is 30 ° or more and 50 ° or less.

Further, the fur brush 41 may be rotated in the direction opposite to that in FIG. 8, that is, in the direction in which the eye direction of the brush bristles 41b is inclined inward in the axial direction from the upstream side to the downstream side in the rotation direction. In this case, since the force from both ends in the width direction toward the center acts on the intermediate transfer belt 8 due to the elastic deformation of the brush bristles 41b, the effect of suppressing the bias is reduced. Therefore, it is preferable to rotate the fur brush 41 in a direction in which the eye direction of the brush bristles 41b is inclined outward in the axial direction from the upstream side to the downstream side in the rotation direction as in the present embodiment.

Others The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the material, thickness and length, density, etc. of the brush bristles 41b are required, in addition to the cleaning effect of the intermediate transfer belt 8, the thickness and material of the intermediate transfer belt 8 which is an object for restricting deviation. It can be changed as appropriate according to the offset prevention effect.

Further, the method of attaching the brush bristles 41b to the rotating shaft 41a is not limited to the method of winding the brush portion 41d in which the brush bristles 41b are transplanted on the belt-shaped base material 41c around the outer peripheral surface of the rotating shaft 41a, for example, the rotating shaft 41a. Brush bristles 41b may be planted on the outer peripheral surface. Even with this configuration, if there is an inclination angle θ in the eye direction of the brush bristles 41b, an offset prevention effect can be obtained.

Further, the image forming apparatus 100 of the present invention is not limited to the color printer as shown in FIG. 1, but is another image forming apparatus provided with an intermediate transfer belt such as a color copier, a digital multifunction device, and a facsimile. You may.

Further, in the above embodiment, as an example of the belt transfer device, the intermediate transfer unit 30 provided with the intermediate transfer belt 8 on which the toner image formed on the photoconductor drums 1a to 1d is primarily transferred is illustrated. The belt transfer device to which is applied is not limited to the intermediate transfer unit 30. For example, a transfer unit for transporting paper using a transport belt, a belt transport device for sucking and holding paper on a transport belt by a paper suction unit provided inside the transport belt, and the like may be used.

INDUSTRIAL APPLICABILITY The present invention can be used in a belt transport device for transporting a sheet such as paper or a toner image by using an endless transport belt. By utilizing the present invention, it is possible to provide a belt transfer device capable of suppressing deviation of the transfer belt with a simple configuration and an image forming device provided with the belt transfer device.

1 Photoreceptor drum (image carrier)
2 Charging device 3 Exposure device 4 Developing device 6a to 6d Primary transfer roller 8 Intermediate transfer belt (conveyor belt)
10 Drive roller 11 Tension roller 19 Belt cleaning unit 30 Intermediate transfer unit (belt transfer device)
30a, 30b Roller support frame 41 Fur brush (brush roller)
41a Rotating shaft 41b Brush bristles 41c Base material 41d Brush part 43 Recovery roller 60 High voltage power supply (voltage application part)
100 Image forming device P Image forming part N Nip part

Claims (5)

With an endless transport belt,
A plurality of belt support rollers for tensioning the transport belt, and
A roller support frame that rotatably supports the belt support roller, and
A brush roller that rotates in the counter direction with respect to the moving direction of the transport belt while in contact with the outer peripheral surface of the transport belt.
A voltage application unit that applies a voltage to the brush roller and
In the belt transfer device equipped with
The brush roller includes a rotation shaft and brush bristles uniformly attached to the outer peripheral surface of the rotation shaft at a predetermined density over substantially the entire axial direction, and the eye direction of the brush bristles is the axial direction. A belt transport device characterized in that the center of the shaft is a axis of symmetry and the two ends are inclined in opposite directions toward both ends in the axial direction. The belt transport device according to claim 1, wherein the eye direction of the brush bristles is inclined outward in the axial direction from the upstream side to the downstream side in the rotation direction of the brush roller. The belt transport device according to claim 1 or 2, wherein the brush bristles have an inclination angle of 30 ° or more and 50 ° or less with respect to the axis of symmetry. The brush roller is characterized in that a brush portion in which the brush bristles are planted on a belt-shaped base material is spirally wound in opposite directions from the center in the axial direction toward both ends. The belt transport device according to any one of claims 1 to 3. The belt transport device according to any one of claims 1 to 4.
An image forming unit that is arranged to face the transport belt and forms an image on the transport belt or on a recording medium that is held and transported by the transport belt.
An image forming apparatus equipped with.

Images