JP2015043027A - Belt conveyance device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt conveyance device that can maintain cleaning performance of a scraper cleaning the rear surface of a belt for a longer period, and an image forming apparatus.SOLUTION: A belt conveyance device 30 includes a movable belt 31 that conveys, while carrying, a toner image directly or with a transfer material, a scraper 37 that is brought into contact with the surface on the opposite side of the surface of the belt 31 on which the toner image is carried, and a holding part 38 that holds the scraper 37 at the end on the opposite side of the end of the scraper 37 in contact with the belt 31, where the scraper 37 has the rigidity larger at the end in contact with the belt 31 than at the end held by the holding part 38.

Description

  The present invention relates to a belt conveyance device used in an image forming apparatus such as a copying machine or a printer using an electrophotographic system or an electrostatic recording system, and the image forming apparatus.

  2. Description of the Related Art Conventionally, as an image forming apparatus using an electrophotographic system or an electrostatic recording system, there is an apparatus having a belt conveyance device including a belt that carries and conveys a toner image on a surface directly or via a transfer material such as paper. In an intermediate transfer type image forming apparatus, a toner image formed in an image forming unit is primarily transferred to an intermediate transfer belt which is an endless belt as an intermediate transfer member, and then the toner image is secondarily transferred to a transfer material. As a result, a recorded image is formed. In the direct transfer type image forming apparatus, the toner image formed in the image forming unit is transferred to a transfer material carried and conveyed on a transfer material carrying belt which is an endless belt as a transfer material carrying member. As a result, a recorded image is formed. As a transfer means for the primary transfer of the toner image to the intermediate transfer belt and the transfer to the transfer material on the transfer material carrying belt, a transfer member that contacts the back surface of the belt opposite to the surface carrying the toner image is used. Widely used.

  For example, when a primary transfer roller, which is a roller-shaped transfer member, is used as the primary transfer unit in the intermediate transfer type image forming apparatus, foreign matters such as toner and paper dust adhered to the back surface of the intermediate transfer belt are transferred. May be affected. As a result, an image defect due to a transfer defect may be caused in the formed image. The same applies to the direct transfer type image forming apparatus.

  Therefore, as described in Patent Document 1, a cleaning unit that acts on the back side of the belt to clean the back side of the belt is provided.

JP-A-11-38774

  Examples of the cleaning means for cleaning the back surface of the belt include a scraper (a spatula-like member) made of a fur brush, a rubber blade, or a sheet-like resin material. Among these, from the viewpoint of cleaning ability, space saving, and cost reduction, a configuration in which foreign matter is physically scraped by a scraper is advantageous.

  However, when wear of the contact portion with respect to the belt advances due to repeated image formation, the scraper may cause chipping of the edge, thereby reducing the cleaning ability and making it impossible to remove foreign matter. Further, the inner peripheral surface of the belt may be damaged due to chipping of the scraper edge. These may affect the transfer efficiency and lead to the occurrence of image defects due to transfer defects (transfer efficiency unevenness).

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a belt conveying device and an image forming apparatus that can maintain the cleaning ability of a scraper for cleaning the back surface of a belt for a longer period of time.

  The above object is achieved by the belt conveyance device and the image forming apparatus according to the present invention. In summary, the first aspect of the present invention is a movable belt that carries and conveys a toner image directly or via a transfer material, and a scraper that contacts a surface of the belt opposite to the side carrying the toner image. And a holding portion that holds the scraper on an end side opposite to the end side that contacts the belt of the scraper, and the rigidity of the scraper is on the end side that contacts the belt. The belt conveying device is characterized in that it is larger than the end side held by the holding portion.

  According to the second aspect of the present invention, the toner image forming means for forming a toner image and the belt conveying device of the present invention are provided, and the toner image formed by the toner image forming means is directly or directly on the belt. An image forming apparatus is provided that is transferred via a transfer material.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to maintain the cleaning capability of the scraper which cleans the back surface of a belt over a long period of time.

1 is a schematic cross-sectional view of an example of an image forming apparatus. FIG. 6 is a schematic cross-sectional view of the vicinity of a belt inner peripheral surface cleaning device. It is a top view of an example of a scraper. It is a top view of other examples of a scraper. FIG. 6 is a schematic cross-sectional view in the vicinity of another example of the belt inner peripheral surface cleaning device. FIG. 6 is a schematic cross-sectional view of another example of an image forming apparatus.

  Hereinafter, the belt conveyance device and the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
1. FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 according to the present exemplary embodiment is a tandem type printer (a multifunction machine having both a copying machine and a printer function) that employs an intermediate transfer method.

  The image forming apparatus 100 includes first, second, third, and fourth image forming units 1Y that are arranged in series along an image transfer surface A that is arranged substantially horizontally on an intermediate transfer belt 31 described later. 1M, 1C, 1K. The image forming apparatus 100 can form a full-color image on the transfer material (sheet material) S by electrophotography in accordance with an image signal transmitted from an external device. The first, second, third, and fourth image forming units 1Y, 1M, 1C, and 1K form yellow (Y), magenta (M), cyan (C), and black (K) toner images, respectively. To do.

  In the present embodiment, the configurations and operations of the first, second, third, and fourth image forming units 1Y, 1M, 1C, and 1K are substantially the same except that the color of the toner used is different. . Therefore, in the following, unless there is a particular need to distinguish, the Y, M, C, and K at the end of the symbol indicating that the element is provided for any color will be omitted, and the element will be described comprehensively. To do.

  The image forming unit 1 includes a photosensitive drum 11 that is a drum-type (cylindrical) electrophotographic photosensitive member (photosensitive member) as an image carrier. The photosensitive drum 11 is rotationally driven by a drive motor (not shown) as drive means in the direction of arrow R1 in the figure. Around the photosensitive drum 11, the following units are arranged in order along the rotation direction of the photosensitive drum 11. First, a charger 12 as a charging unit is arranged. Next, an exposure device 13 as an exposure unit is arranged. Next, a developing device 14 as a developing unit is disposed. Next, a photoconductor cleaning device 15 as a photoconductor cleaning unit is disposed.

  Further, an intermediate transfer belt 31 that is an endless belt as an intermediate transfer member is disposed so as to face each photosensitive drum 11 of each image forming unit 1. The intermediate transfer belt 31 is an example of a movable belt that carries and conveys a toner image directly or via a transfer material. The intermediate transfer belt 31 is stretched with a predetermined tension by three support rollers including a drive roller 33, a tension roller 34, and a two-transfer counter roller 32. The intermediate transfer belt 31 rotates (circulates) in the direction of the arrow R2 in the figure when the driving roller 33 is rotationally driven by a driving motor (not shown) as a driving means. On the inner peripheral surface (back surface) side of the intermediate transfer belt 31, primary transfer rollers 35 </ b> Y and 35 </ b> M that are roller-shaped primary transfer members serving as primary transfer units are located at positions facing the photosensitive drums 11 </ b> Y, 11 </ b> M, 11 </ b> C, and 11 </ b> K. , 35C and 35K are arranged. Each primary transfer roller 35 is in contact with the inner peripheral surface of the intermediate transfer belt 31 and is biased (pressed) toward the photosensitive drum 11 via the intermediate transfer belt 31, and each of the photosensitive drums 11 and the intermediate transfer belt 31. Is formed as a primary transfer portion (primary transfer nip) N1. Further, on the outer peripheral surface (front surface) side of the intermediate transfer belt 31, a secondary transfer roller 41 that is a roller-like secondary transfer member as a secondary transfer unit is disposed at a position facing the secondary transfer counter roller 32. Has been. The secondary transfer roller 41 is in contact with the outer peripheral surface of the intermediate transfer belt 31 and is biased (pressed) toward the secondary transfer counter roller 32 via the intermediate transfer belt 31. A secondary transfer portion (secondary transfer nip) N2 in contact with the transfer belt 31 is formed. On the outer peripheral surface side of the intermediate transfer belt 31, an outer peripheral surface cleaning device 36 as an outer peripheral surface cleaning unit that cleans the outer peripheral surface of the intermediate transfer belt 31 is disposed at a position facing the driving roller 33. Further, as will be described in detail later, an inner peripheral surface cleaning device 39 as an inner peripheral surface cleaning unit for cleaning the inner peripheral surface of the intermediate transfer belt 31 is disposed on the inner peripheral surface side of the intermediate transfer belt 31. . In this embodiment, the inner peripheral surface cleaning device 39 includes the primary transfer unit N1 and the tension roller 34 in the image forming unit 1K that is the most downstream in the moving direction of the intermediate transfer belt 31 (hereinafter also simply referred to as “belt moving direction”). Is located between.

  In this embodiment, the intermediate transfer belt 31, the support rollers 32, 33, and 34, the primary transfer rollers 35, the outer peripheral surface cleaning device 36, the inner peripheral surface cleaning device 39, and the like constitute a belt conveyance device (belt unit) 30. ing. The belt conveyance device 30 may be integrated by a frame body (not shown) or the like, and may be integrally attached to and detached from the apparatus main body of the image forming apparatus 100.

  During image formation, the surface of the rotating photosensitive drum 11 is uniformly charged by the charger 12. Next, the surface of the charged photosensitive drum 11 is irradiated with light (image light) corresponding to image information from the exposure device 13, and an electrostatic image (electrostatic latent image) is formed on the surface of the photosensitive drum 11. . The electrostatic image formed on the photosensitive drum 11 is developed as a toner image after the toner is transferred by the developing device 14. The toner image formed on the photosensitive drum 11 is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 31 by the action of the primary transfer roller 35 in the primary transfer portion N1. At this time, the primary transfer roller 35 is supplied with a primary transfer bias, which is a DC voltage having a polarity opposite to the charging polarity (normal charging polarity) of the toner at the time of development, from a primary transfer power supply as a primary transfer bias applying unit (not shown). Applied. For example, when forming a full-color image, the toner images formed on the photosensitive drums 11Y, 11M, 11C, and 11K of the image forming units 1Y, 1M, 1C, and 1K are sequentially superimposed on the same image position on the intermediate transfer belt 31. Primary transfer is performed so as to match.

  On the other hand, the transfer material S stored in the paper feed cassettes 61, 62, 63, 64 is conveyed to the transfer material conveyance path 81 as one of the transfer material supply rollers 71, 72, 73, 74 rotates. . Further, the registration roller 75 feeds the transfer material S to the secondary transfer portion N2 in synchronization with the toner image on the intermediate transfer belt 31. In the secondary transfer portion N2, the toner image is secondarily transferred from the intermediate transfer belt 31 onto the transfer material S by the action of the secondary transfer roller 41. At this time, a secondary transfer bias having a DC voltage having a polarity opposite to the charging polarity of the toner at the time of development is applied to the secondary transfer roller 41 from a secondary transfer power source as a secondary transfer bias applying unit (not shown). The

  The transfer material S to which the toner image has been transferred is conveyed by a conveyance belt 42 to a thermal fixing device 5 as a fixing unit. Then, the toner image is fixed to the surface of the transfer material S by being heat-pressed by the heat fixing device 5, and a full color recording image is formed, for example. Thereafter, the transfer material S is sent to the discharge tray 65 through the discharge conveyance path 82.

  The toner remaining on the surface of the photosensitive drum 11 after the primary transfer (primary transfer residual toner) is removed from the surface of the photosensitive drum 11 by the photosensitive member cleaning device 15 and collected. The toner remaining on the outer peripheral surface of the intermediate transfer belt 31 after the secondary transfer (secondary transfer residual toner) is removed from the intermediate transfer belt 31 by the outer peripheral surface cleaning device 36 and collected.

  In this embodiment, the image forming units 1Y, 1M, 1C, and 1K constitute a toner image forming unit.

2. Inner peripheral surface cleaning device The inner peripheral surface of the intermediate transfer belt 31 includes toner, external additives, and paper powder that wrap around the inner peripheral surface of the intermediate transfer belt 31 from a space near both ends in a direction intersecting the belt moving direction. Foreign matter such as may adhere. For example, when the material of the primary transfer roller 35 and the secondary transfer counter roller 32 is a sponge, a material that exudes from the sponge may adhere to the inner peripheral surface of the intermediate transfer belt 31. In a place where such foreign matter adheres to the inner peripheral surface of the intermediate transfer belt 31, the transfer efficiency is lowered, and the toner image is not normally transferred to the transfer material S, resulting in an image defect. Therefore, it is necessary to remove foreign matters from the inner peripheral surface of the intermediate transfer belt 31.

  FIG. 2 is a schematic cross-sectional view of the inner peripheral surface cleaning device 39 in the present embodiment. FIG. 2 also shows other elements in the vicinity of the inner peripheral surface cleaning device 39.

  The inner peripheral surface cleaning device 39 is a scraper (a spatula-like member, a blade-like member, or a plate-like member) that comes into contact with the surface (that is, the inner peripheral surface or the back surface) opposite to the side on which the toner image is carried on the intermediate transfer belt 31. Member) 37. Further, the inner peripheral surface cleaning device 39 includes a holding portion 38 that holds the scraper 37 on the end portion side opposite to the end portion side that contacts the intermediate transfer belt 31 of the scraper 37. The inner peripheral surface cleaning device 39 brings the edge of the scraper 37 into contact with the inner peripheral surface of the intermediate transfer belt 31, and rubs the inner peripheral surface of the moving intermediate transfer belt 31 with the scraper 37. Scrape off the foreign material from the inner peripheral surface. In the present exemplary embodiment, the holding unit 38 also functions as a storage unit that stores foreign matter removed from the inner peripheral surface of the intermediate transfer belt 31 by the scraper 37 on the upper surface in the drawing.

  More specifically, in this embodiment, the scraper 37 is a flat plate-like member having a substantially rectangular shape in plan view (see FIG. 3). Of the two sides that are substantially orthogonal, one side in the longitudinal direction is arranged in a direction that intersects the belt moving direction (substantially orthogonal in this embodiment). Further, the edge of one end portion 37 b on one side in the short direction is brought into contact with the inner peripheral surface of the intermediate transfer belt 31, and the other end portion 37 a is held by the holding portion 38. The scraper 37 is arranged (counter contact) so that the end 37b on the side in contact with the intermediate transfer belt 31 faces the upstream side with respect to the belt moving direction.

  Here, as described above, as a configuration for cleaning the inner peripheral surface of the intermediate transfer belt 31, there is a configuration using a fur brush or a rubber blade. On the other hand, as in this embodiment, a flat scraper 37 composed of a resin sheet or a thin metal plate is held by a holding portion 38, and the edge of the scraper 37 is brought into contact with the inner peripheral surface of the intermediate transfer belt 31. There is a configuration (hereinafter also referred to as “scraper configuration”) for scraping off foreign matter. In addition to being excellent in the ability to scrape off the adhered foreign matter, the scraper configuration is low in cost, and therefore has a high advantage as a configuration for cleaning the inner peripheral surface of the intermediate transfer belt 31.

  In the scraper configuration, the scraper 37 applies (presses) pressure to the intermediate transfer belt 31 with a repulsive force generated by forced displacement. For this reason, the scraping of the edge of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31 due to the progress (durability) of the image formation due to repeated (endurance), scratches on the inner peripheral surface of the intermediate transfer belt 31. There is a possibility that a phenomenon such as sticking will occur.

  Therefore, in order to extend the life of the scraper 37 and the intermediate transfer belt 31, it is desirable to reduce the contact pressure as much as possible while giving the contact pressure necessary for cleaning. However, on the other hand, when the contact pressure distribution becomes non-uniform due to, for example, undulation of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31, the scraper 37 is unevenly worn, so that the cleaning ability can be uneven. End up. For this reason, the edge of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31 is required to have a large rigidity that does not cause undulation or the like.

  Therefore, in this embodiment, as described in detail below, (A) the contact pressure of the scraper 37 with respect to the intermediate transfer belt 31 can be reduced, while (B) the rigidity of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31 can be increased. Like that. Accordingly, it is possible to achieve the long life of parts such as the scraper 37 and the intermediate transfer belt 31 while maintaining the cleaning ability.

3. Next, the scraper 37 of this embodiment will be described in detail. FIG. 3 is a plan view of the scraper 37 of the present embodiment.

  In this embodiment, the scraper 37 is made of a PET (polyethylene terephthalate) sheet having a thickness of 250 μm, which has such a rigidity that the above-described undulation of the edge does not occur. The scraper 37 has a predetermined range (adhesion region) 37c from one end (fixed end) 37a in the short direction to the other end (free end) 37b by a double-sided tape (not shown) as fixing means. Affixed to the holding unit 38 and held. In the scraper 37, the edge on the inner peripheral surface side of the intermediate transfer belt 31 at the free end 37b is brought into contact with the inner peripheral surface of the intermediate transfer belt 31 as a contact portion 37d.

  The scraper 37 is provided with a plurality of slit-shaped opening portions 37e extending substantially parallel to the longitudinal direction in the vicinity of the adhesion region 37c. In particular, in the present embodiment, the apertures 37e are arranged in two rows and in a staggered manner.

  That is, the rigidity of the scraper 37 is greater on the end 37 b side in contact with the intermediate transfer belt 31 than on the end 37 a held by the holding unit 38. Therefore, in this embodiment, the scraper 37 has a plurality of opening portions 37e arranged in a direction intersecting with the belt moving direction (substantially orthogonal in this embodiment) on the end portion 37a side held by the holding portion 38. Have In particular, in the present embodiment, the plurality of apertures 37e are arranged in at least two rows, and the apertures 37 in adjacent rows are alternately displaced in the direction intersecting the belt moving direction (alternately). Has been placed.

  By providing the opening 37e, the cross-sectional secondary moment in the region near the opening 37e is reduced, that is, the rigidity is reduced. Therefore, when the contact portion 37d of the scraper 37 with respect to the intermediate transfer belt 31 is forcibly displaced by the intermediate transfer belt 31, the region in the vicinity of the opening portion 37e is more easily deformed.

  In the image forming apparatus 100 of this embodiment, the contact linear pressure of the scraper 37 necessary for cleaning the foreign matter attached to the inner peripheral surface of the intermediate transfer belt 31 is 0.6 gf / mm. On the other hand, the contact linear pressure of the scraper 37 of the present embodiment is 0.8 gf / mm, which satisfies the cleaning condition. On the other hand, the contact line pressure of the scraper 37, which is made of a PET sheet of the same material and thickness and does not have the opening 37e, is 3.5 gf / mm, and although the cleaning condition is satisfied, the intermediate transfer is caused by excessive frictional force. There is a possibility that an adverse effect such as a scratch on the inner peripheral surface of the belt 31 may occur.

  Here, in this embodiment, as shown in FIG. 3, the opening portions 37e of the scraper 37 are arranged in a staggered manner, and the end portions of the opening portions 37e adjacent in the longitudinal direction of the scraper 37 are slightly It overlaps. That is, in the present embodiment, among the opening portions 37e in the adjacent rows, a part of the end portions of the opening portions 37e adjacent in the direction intersecting the belt moving direction is partially in the direction intersecting the belt moving direction. It overlaps. In this embodiment, the overlap amount X is 1 mm. Accordingly, when the cross section is cut substantially perpendicularly to the longitudinal direction of the scraper 37, the opening 37e appears at any position in the substantially entire region of the scraper 37 in the longitudinal direction. Therefore, the contact pressure distribution can be made more uniform.

  However, in this embodiment, as shown in FIG. 3, the opening 37e is provided in the predetermined ranges (longitudinal region) 37g, 37g inside the longitudinal ends 37f, 37f of the scraper 37. Absent. That is, the scraper 37 has regions 37g and 37g in which the opening portion 37e is not provided at both ends in the direction intersecting the belt moving direction. Thus, the rigidity of the longitudinal end regions 37g and 37g of the scraper 37 is increased as a region without the opening 37e. This is because the end portion in the direction intersecting the moving direction of the intermediate transfer belt 31 is released and thus easily displaced, and the contact pressure tends to be smaller at the end portion than at the longitudinal center portion of the scraper 37. It is. By providing an area without the opening 37e in the vicinity of the longitudinal ends 37f and 37f of the scraper 37 and appropriately increasing the rigidity of the longitudinal end areas 37g and 37g of the scraper 37, the longitudinal direction of the scraper 37 The contact pressure between the central portion and the end portion can be made more uniform.

  As described above, according to the present embodiment, it is possible to suppress the occurrence of undulation or the like in the vicinity of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31, thereby reducing uneven wear of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31. At the same time, since the contact pressure of the scraper 37 can be suppressed to the minimum contact pressure necessary for cleaning foreign matter, the life of the scraper 37 and the intermediate transfer belt 31 can be extended without damaging the intermediate transfer belt 31. realizable. Therefore, according to the present embodiment, the cleaning ability of the scraper 37 that cleans the back surface of the intermediate transfer belt 31 can be maintained for a longer period.

  In this example, in order to make the contact pressure distribution of the scraper 37 more uniform, the opening portions 37e are arranged in a staggered manner. However, the present invention is not limited to this. For example, there are cases where the life of the parts can be extended even if the uniformity of the contact pressure distribution of the scraper 37 is relatively low. In such a case, for example, holes having various shapes such as round holes (FIG. 4A) and square holes (FIG. 4B) may be arranged in a line in the longitudinal direction of the scraper 37. Needless to say, a configuration in which the contact pressure distribution of the scraper 37 can be made more uniform by arranging a plurality of holes having various shapes such as round holes and square holes in place of the slit holes in the present embodiment.

  The material of the scraper 37 is not limited to the resin sheet as in this embodiment, and a metal such as a SUS (stainless steel) thin plate having a thickness of about 100 μm to 300 μm may be used.

Example 2
Next, another embodiment of the present invention will be described. The basic configuration and operation of the belt conveyance device and the image forming apparatus of the present embodiment are the same as those of the first embodiment. Therefore, elements having the same functions or configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 5 is a schematic cross-sectional view of the inner peripheral surface cleaning device 39 in the present embodiment.

  In the present embodiment, the scraper 37 is configured by bonding and bonding a first plate-like portion 37h having a lower rigidity and a second plate-like portion 37i having a higher rigidity. The side fixed to the holding portion 38 is a first plate-shaped portion 37h, and the side contacting the inner peripheral surface of the intermediate transfer belt 31 is a second plate-shaped portion 37i. More specifically, in the present embodiment, the first plate-like portion 37h is a flat plate member (first flat plate) having a substantially rectangular shape in plan view. The second plate-like portion 37i is a flat plate-like member (second flat plate) that is shorter in the short direction than the first plate-like portion 37h and has a substantially rectangular shape in plan view. Then, the first plate-like portion 37 h overlaps with a predetermined range on one end (free end) side in the short side direction, and a part of the first plate-like portion 37 h projects to the inner peripheral surface side of the intermediate transfer belt 31. Then, the second plate-like portion 37i is attached. In this embodiment, the first plate-like portion 37h and the second plate-like portion 37i are fixed by a double-sided tape (not shown) as a fixing means.

  In other words, in the present embodiment, the scraper 37 has a first plate-like portion 37h and a second plate-like portion 37i having different rigidity, and the first plate-like portion 37h having lower rigidity is the holding portion 38. The second plate-like portion 38 i having higher rigidity is in contact with the intermediate transfer belt 31.

  The rigidity of the plate-like portion (a flat plate in the present embodiment) is determined by the cross-sectional second moment that depends on the Young's modulus of the material and the shape such as its thickness. In this example, the first plate-shaped portion 37h was a PET sheet having a thickness of 125 μm, and the second plate-shaped portion 37i was a PET sheet having a thickness of 250 μm. Thus, even for the same material, the rigidity is changed by changing the thickness. However, the present invention is not limited to this. For example, the rigidity may be increased by increasing the Young's modulus by using, for example, SUS as the material of the second plate-shaped portion 37i.

  Also in the configuration of the present embodiment, as in the first embodiment, the occurrence of undulation in the vicinity of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31 is suppressed, and the uneven wear of the contact portion of the scraper 37 with respect to the intermediate transfer belt 31 is suppressed. Can be reduced. At the same time, since the contact pressure of the scraper 37 can be suppressed to the minimum contact pressure necessary for cleaning foreign matter, the life of the scraper 37 and the intermediate transfer belt 31 can be extended without damaging the intermediate transfer belt 31. it can.

Others While the present invention has been described with reference to specific embodiments, the present invention is not limited to this.

  For example, in the above-described embodiments, the image forming apparatus has been described as adopting the intermediate transfer method, but the present invention can be equally applied to a direct transfer type image forming apparatus. In other words, the present invention includes a toner image forming unit that forms a toner image and a belt conveying device, and the toner image formed by the toner image forming unit is directly or via a transfer material on the belt of the belt conveying device. The present invention can be applied to an image forming apparatus of any mode that is transferred. FIG. 6 is a schematic cross-sectional view showing a schematic configuration of a main part of a tandem type image forming apparatus adopting a direct transfer method. In the image forming apparatus of FIG. 6, elements having the same or corresponding functions and configurations as those of the image forming apparatus of FIG. The image forming apparatus 100 of FIG. 6 includes a transfer material carrying belt 310 that is an endless belt as a transfer material carrying body that carries and conveys the transfer material S. The transfer material carrying belt 310 is an example of a movable belt that carries and conveys a toner image directly or via a transfer material. The toner images formed by the image forming units 1 of the respective colors are transferred in each transfer unit N so as to be sequentially superimposed on the transfer material S that is carried and conveyed by the transfer material carrying belt 310. Thereafter, the toner image is fixed on the transfer material S. As an inner peripheral surface cleaning means for cleaning the inner peripheral surface of the transfer material carrying belt 310, an inner peripheral surface cleaning device 39 provided with a scraper 37 substantially the same as that in the above-described embodiment can be used. Thereby, the effect similar to the above-mentioned Example can be acquired.

DESCRIPTION OF SYMBOLS 11 Photosensitive drum 30 Belt conveying apparatus 31 Intermediate transfer belt 35 Primary transfer roller 37 Scraper 37e Opening part 37h First plate-like part 37i Second plate-like part 38 Holding part 39 Inner peripheral surface cleaning apparatus 100 Image forming apparatus

Claims (9)

A movable belt that carries and conveys a toner image directly or via a transfer material;
A scraper that contacts a surface of the belt opposite to a side on which a toner image is carried;
A holding portion for holding the scraper on an end side opposite to an end side contacting the belt of the scraper;
Have
The belt conveying apparatus according to claim 1, wherein the scraper has a rigidity higher on an end side in contact with the belt than on an end side held by the holding unit.   The belt conveying device according to claim 1, wherein the scraper has a plurality of apertures arranged in a direction intersecting a moving direction of the belt on an end side held by the holding unit. .   The plurality of apertures are arranged in at least two rows, and the apertures in adjacent rows are arranged at positions that are alternately shifted in a direction intersecting the moving direction of the belt. Item 3. The belt conveyance device according to Item 2.   Among the apertures in the adjacent rows, the ends of the apertures adjacent in the direction intersecting the moving direction of the belt partially overlap in the direction intersecting the moving direction of the belt. The belt conveyance device according to claim 3.   5. The belt conveyance device according to claim 4, wherein the scraper has regions where the opening portions are not provided at both end portions in a direction intersecting a moving direction of the belt.   The scraper has a first plate-like portion and a second plate-like portion having different rigidity, and a first plate-like portion having a lower rigidity is held by the holding portion, and a second higher-rigidity second The belt conveying device according to claim 1, wherein the plate-like portion contacts the belt.   The belt according to any one of claims 1 to 6, wherein the scraper is arranged so that an end portion on a side in contact with the belt faces an upstream side with respect to a moving direction of the belt. Conveying device.   A toner image forming unit that forms a toner image and the belt conveyance device according to claim 1, wherein the toner image formed by the toner image forming unit is directly applied to the belt. Alternatively, the image forming apparatus is transferred via a transfer material.   A transfer member that contacts a surface of the belt opposite to the side on which the toner image is carried and that transfers the toner image formed by the toner image forming unit to the belt directly or via a transfer material; The image forming apparatus according to claim 8.

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