JP6287316B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that cleans the surface of a belt-shaped image carrier such as an intermediate transfer belt with a cleaning unit.

  2. Description of the Related Art An electrophotographic image forming apparatus that transfers a toner image formed on a photosensitive member to an intermediate transfer belt and transfers the toner image transferred to the intermediate transfer belt onto a transfer material such as paper has become widespread. Such an image forming apparatus includes a cleaning unit that cleans the surface of the intermediate transfer belt after the toner image is transferred from the intermediate transfer belt to the transfer material. The cleaning unit is provided with a blade for removing the toner remaining on the surface of the intermediate transfer belt, and the toner removed by the blade is upstream of the blade in the rotation direction of the intermediate transfer belt. A cleaning seal is provided to prevent scattering. This cleaning seal has a sheet-like member disposed along the width direction of the intermediate transfer belt, and abuts the sheet material against the intermediate transfer belt, and a moquette material that forms side seals at both ends of the sheet material. It is the arranged configuration.

  FIG. 8 shows a configuration of a cleaning seal of a conventional cleaning unit. In FIG. 8, the left side is a position near the end in the width direction of the intermediate transfer belt 604, the right side is a position near the center in the width direction of the intermediate transfer belt 604, and the lower side is a position upstream in the rotation direction of the intermediate transfer belt 604. It is. A sheet material 601 is arranged along the width direction of the intermediate transfer belt 604 (lateral direction in FIG. 8). In order to prevent the toner from scattering to the side of the intermediate transfer belt 604, side seals 602 are provided along the longitudinal direction of the intermediate transfer belt 604 (vertical direction in FIG. 8) on the sides of both ends of the sheet material 601. Is arranged. The side seal 602 is formed of a moquette material, and fine hairs protrude from the side seal 602 at a position facing the sheet material 601. The sheet material 601 is in contact with the protruding hair of the side seal 602, but does not overlap with the side seal 602. The sheet material 601 and the side seal 602 constitute a cleaning seal for preventing toner scattering to the upstream side in the rotation direction of the intermediate transfer belt 604.

  By the way, as a method of performing the meandering regulation of the intermediate transfer belt 604 with an inexpensive configuration, there is a method of regulating the meandering by attaching a rib to the back surface of the intermediate transfer belt 604. In this method, a reinforcing tape 605 for reinforcing the strength of the intermediate transfer belt 604 to prevent breakage is applied to both ends of the surface (image forming surface) of the intermediate transfer belt 604, and the reinforcing tape 605 is applied. Sometimes the start and end parts overlap. There is a step in the overlapping portion of the reinforcing tape 605. In recent years, as a result of meeting the needs for downsizing of the image forming apparatus, as shown in FIG. 8, the position of the reinforcing tape 605 and the cleaning seal of the cleaning unit are configured on the width direction of the intermediate transfer belt 604. The position of the sheet material 601 overlaps. For this reason, the reinforcing tape 605 is attached so that the step of the overlapping portion of the reinforcing tape 605 does not collide with the leading end of the sheet material 601 of the cleaning seal when the intermediate transfer belt 604 rotates in the forward direction. Yes. FIG. 9 shows the direction in which the reinforcing tape 605 is applied. As shown in FIG. 9A, the reinforcing tape 605 is attached so that the level difference of the overlapping portion is in a direction that does not collide with the front end of the sheet material 601 of the cleaning seal when the intermediate transfer belt 604 rotates in the forward direction. Yes.

  However, in the image forming apparatus, the intermediate transfer belt is slightly rotated in the reverse direction at the end of the job or periodically as a countermeasure when foreign matter is caught in the blade of the cleaning unit. Therefore, when rotating in the reverse direction, as shown in FIG. 9B, the leading end of the sheet material 601 collides with the step of the overlapping portion of the reinforcing tape 605. When such a collision occurs, as shown in FIG. 9B, the leading end of the sheet material 601 is bent, and then, when the leading end of the sheet material 601 returns to the original state, it rides on the protruding hair of the moquette material. . Therefore, there is a problem that a gap is formed between the intermediate transfer belt and the sheet material, and toner is scattered from the gap, so that the image is stained.

  Conventionally, as a technique for solving the problem caused by the external force acting on the overlapping portion of the reinforcing tape affixed to the end of the intermediate transfer belt, a load that generates a load due to the external force acting on the overlapping portion of the reinforcing tape is known. A technique for stopping the intermediate transfer belt at a position other than the working area has been proposed (for example, see Patent Document 1).

JP 2009-122389 A

  However, in the technique proposed in Patent Document 1 described above, the rotation position of the intermediate transfer belt is detected by an optical sensor, and the drive motor of the intermediate transfer belt is controlled based on the detection result to determine the stop position of the intermediate transfer belt. Since it must be determined, complicated processing is required.

  In view of the above, the present invention provides a sheet material that cleans the surface of an image carrier and a reinforcing material that reinforces the image carrier when a belt-like image carrier such as an intermediate transfer belt rotates in the reverse direction. An object of the present invention is to reduce the bending of the sheet material caused by contact with the step of the mating portion with a simpler configuration.

In order to solve the above-described problems and achieve the object of the present invention, an image forming apparatus of the present invention includes a belt-shaped image carrier that carries toner on the surface, and the surface of the image carrier in the rotational direction of the image carrier. It provided so as to have a superimposed portion I along, a reinforcing member for reinforcing the image bearing member, provided in the width direction of the image carrier, a cleaning member for removing toner remaining on the surface of the image bearing member And a receiving member that is provided upstream of the cleaning member in the rotation direction of the image carrier and in the width direction of the image carrier and that receives the toner removed by the cleaning member. There is a protruding portion that collides with the overlapped portion of the reinforcing member on the side in the width direction of the image carrier, and the protruding portion of the receiving member collides with the overlapped portion of the reinforcing member by point contact. Is formed.

  According to the present invention, since the portion projecting toward the side seal material is provided at the end of the sheet material, even if the sheet material collides with the step of the overlapping portion of the reinforcing material at the end of the image carrier. The force applied to the sheet material by the collision is weakened by the weight of the protruding portion. Therefore, it is possible to reduce the bending of the sheet material caused by the contact between the sheet material and the step of the overlapping portion of the reinforcing material at the end of the image carrier when the image carrier is rotated in the reverse direction. As a result, it is possible to ensure the sealing performance when the image carrier is rotated in the reverse direction, and to prevent image smearing due to toner scattering.

FIG. 2 is a diagram illustrating the configuration of an image forming unit, an intermediate transfer belt, a secondary transfer unit, a fixing unit, and the like of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the meandering prevention mechanism in embodiment of this invention. FIG. 3 is a diagram illustrating a configuration of a cleaning unit for an intermediate transfer belt in an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a cleaning unit for an intermediate transfer belt in an embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a cleaning unit for an intermediate transfer belt in an embodiment of the present invention. It is a figure which shows the shape of the sheet | seat material of the cleaning seal in embodiment of this invention. It is a figure which shows the shape of the sheet | seat material of the cleaning seal | sticker which concerns on the modification of this invention. It is a figure which shows the structure of the cleaning seal | sticker of the conventional cleaning unit. It is a figure which shows the affixing direction of the reinforcement tape to an intermediate transfer belt.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Note that, in the following description and each drawing, the same elements or elements having the same functions are denoted by the same reference numerals, and redundant descriptions are omitted.

[Configuration example of image forming apparatus]
FIG. 1 is an overall configuration diagram showing an outline of a system configuration of an image forming apparatus according to an embodiment of the present invention. In this embodiment, a case where the present invention is applied to a copying machine is taken as an example.

  As shown in FIG. 1, the image forming apparatus 1 according to the present embodiment employs an electrophotographic system that forms an image using static electricity. Yellow (Y), magenta (M), cyan (C ) And black (K) four color toners. The image forming apparatus 1 includes a document conveying unit 10, a paper storage unit 20, an image reading unit 30, an image forming unit 40, an intermediate transfer belt 50, a secondary transfer unit 60, a fixing unit 70, and a control. And a substrate 80.

  The document transport unit 10 includes a document feed table 11 on which a document is set, a plurality of rollers 12, a transport drum 13, a transport guide 14, a document discharge roller 15, and a document discharge tray 16. The documents G set on the document feeder 11 are conveyed one by one to the reading position of the image reading unit 30 by the plurality of rollers 12 and the conveying drum 13. The conveyance guide 14 and the document discharge roller 15 discharge the document G conveyed by the plurality of rollers 12 and the conveyance drum 13 to the document discharge tray 16.

  The image reading unit 30 reads an image of the document G transported by the document transport unit 10 or the document placed on the document table 31 and generates image data. Specifically, the image of the original G is irradiated by the lamp L. The reflected light from the document G based on the light emitted from the lamp L is guided in the order of the first mirror unit 32, the second mirror unit 33, and the lens unit 34, and forms an image on the light receiving surface of the image sensor 35. The image sensor 35 photoelectrically converts incident light and outputs a predetermined image signal. The output image signal is created as image data by A / D conversion.

  The image reading unit 30 has an image reading control unit 36. The image reading control unit 36 performs well-known image processing such as shading correction, dither processing, and compression on image data created by A / D conversion, and stores the image data in a RAM (not shown) mounted on the control board 80. To do. Note that the image data is not limited to data output from the image reading unit 30, and may be data received from an external device such as a personal computer connected to the image forming apparatus 1 or another image forming apparatus.

  The paper storage unit 20 is disposed in the lower part of the apparatus main body, and a plurality of paper storage units 20 are provided according to the size and type of the paper S. The sheet S is fed by the sheet feeding unit 21 and sent to the transport unit 23, and is transported by the transport unit 23 to the secondary transfer unit 60 that is a transfer position. Further, a manual feed portion 22 is provided in the vicinity of the paper storage portion 20. From the manual feed section 22, paper of a size not set in the paper storage section 20, tag paper having a tag, or special paper such as an OHP sheet set by the user is sent to the transfer position.

  An image forming unit 40 and an intermediate transfer belt 50 are disposed between the image reading unit 30 and the paper storage unit 20. The image forming unit 40 includes four image forming units 40Y, 40M, 40C, and 40K in order to form toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K). .

  The first image forming unit 40Y forms a yellow toner image, and the second image forming unit 40M forms a magenta toner image. The third image forming unit 40C forms a cyan toner image, and the fourth image forming unit 40K forms a black toner image. These four image forming units 40Y, 40M, 40C, and 40K have the same configuration. Therefore, here, the first image forming unit 40Y will be described.

  The first image forming unit 40Y includes a drum-shaped photoconductor 41, a charging unit 42 disposed around the photoconductor 41, an exposure unit 43, a developing unit 44, and a cleaning unit 45. . The photoconductor 41 rotates under driving by a drive motor (not shown). The charging unit 42 uniformly charges the surface of the photoconductor 41 by applying a charge to the photoconductor 41. The exposure unit 43 forms an electrostatic latent image on the photoconductor 41 by exposing the surface of the photoconductor 41 based on image data read from the document G or image data transmitted from an external device. To do.

  The developing unit 44 develops the electrostatic latent image formed on the photoconductor 41 using a two-component developer composed of toner and carrier. The toner is particles that form an image. The carrier has a function of imparting an appropriate charge to the toner by frictional charging in mixing with the toner in the developing unit 44, a function of transporting the toner to the developing area facing the photoconductor 41, and an electrostatic on the photoconductor 41. It has a function of forming a developing electric field so that the toner can be faithfully developed on the latent image. The developing unit 44 attaches yellow toner to the electrostatic latent image formed on the photoreceptor 41. As a result, a yellow toner image is formed on the surface of the photoreceptor 41.

  The developing unit 44 of the second image forming unit 40M attaches magenta toner to the photoconductor 41, and the developing unit 44 of the third image forming unit 40C attaches cyan toner to the photoconductor 41. Then, the developing unit 44 of the fourth image forming unit 40K adheres black toner to the photoconductor 41.

  The cleaning unit 45 removes the toner remaining on the surface of the photoreceptor 41.

  The toner adhering to the photoreceptor 41 is transferred to the intermediate transfer belt 50 (an example of a belt-like image carrier). The intermediate transfer belt 50 is formed in an endless shape and is stretched around a plurality of rollers. The intermediate transfer belt 50 rotates (runs) in a direction opposite to the rotation (movement) direction of the photoconductor 41 under the drive of a drive motor (not shown).

  A primary transfer portion 51 is provided at a position on the intermediate transfer belt 50 that faces the photoreceptor 41 of each of the image forming units 40Y, 40M, 40C, and 40K. The primary transfer unit 51 transfers the toner attached on the photoreceptor 41 to the intermediate transfer belt 50 by applying a voltage having a polarity opposite to that of the toner to the intermediate transfer belt 50.

  As the intermediate transfer belt 50 rotates, the toner images formed by the four image forming units 40Y, 40M, 40C, and 40K are sequentially transferred onto the surface of the intermediate transfer belt 50. Thus, a color image is formed on the intermediate transfer belt 50 by overlapping toner images of yellow, magenta, cyan, and black.

  The cleaning unit 53 faces the intermediate transfer belt 50. The cleaning unit 53 cleans the surface of the intermediate transfer belt 50 that has finished transferring the toner image onto the paper S.

  A secondary transfer unit 60 is disposed in the vicinity of the intermediate transfer belt 50 and downstream of the transport unit 23 in the paper transport direction. The secondary transfer unit 60 transfers the toner image formed on the outer peripheral surface of the intermediate transfer belt 50 to the sheet S by bringing the sheet S conveyed by the conveyance unit 23 into contact with the intermediate transfer belt 50.

  The secondary transfer unit 60 has a secondary transfer roller 61. The secondary transfer roller 61 is pressed against the counter roller 52 via the intermediate transfer belt 50. A portion where the secondary transfer roller 61 and the intermediate transfer belt 50 come into contact becomes a secondary transfer nip portion 62. The position of the secondary transfer nip portion 62 is a transfer position at which the toner image formed on the outer peripheral surface of the intermediate transfer belt 50 is transferred to the paper S.

  A fixing unit 70 is provided on the discharge side of the sheet S in the secondary transfer unit 60. The fixing unit 70 pressurizes and heats the paper S to fix the transferred toner image on the paper S. The fixing unit 70 includes, for example, a fixing upper roller 71 and a fixing lower roller 72 that are a pair of fixing members. The upper fixing roller 71 and the lower fixing roller 72 are arranged in pressure contact with each other, and a fixing nip portion is formed at the pressure contact portion between the upper fixing roller 71 and the lower fixing roller 72.

  A heating unit is provided inside the fixing upper roller 71. The roller portion of the fixing upper roller 71 is warmed by the radiant heat from the heating portion. Then, the heat of the roller portion of the fixing upper roller 71 is transmitted to the paper S, whereby the toner image on the paper S is fixed.

  The sheet S is conveyed so that the surface (fixed target surface) onto which the toner image is transferred by the secondary transfer unit 60 faces the fixing upper roller 71 and passes through the fixing nip portion. Accordingly, the sheet S that passes through the fixing nip portion is pressed by the upper fixing roller 71 and the lower fixing roller 72 and heated by the heat of the roller portion of the upper fixing roller 71.

  A switching gate 24 is disposed downstream of the fixing unit 70 in the conveyance direction of the paper S. The switching gate 24 switches the transport path of the paper S that has passed through the fixing unit 70. That is, the switching gate 24 moves the paper S straight when performing face-up paper discharge in image formation on one side of the paper S. As a result, the paper S is discharged by the pair of paper discharge rollers 25. The switching gate 24 guides the paper S downward when performing face-down paper discharge in image formation on one side of the paper S and when performing image formation on both sides of the paper S.

  When face-down paper discharge is performed, the paper S is guided downward by the switching gate 24, and then the front and back of the paper S is reversed and transported upward by the paper reversal transport unit 26. As a result, the paper S whose front and back are reversed is discharged by the pair of paper discharge rollers 25. When image formation is performed on both sides of the paper S, the paper S is guided downward by the switching gate 24, and then the front and back of the paper S are reversed by the paper reversing conveyance unit 26. Then, the sheet S with the front and back reversed is sent again to the transfer position by the refeed path 27.

  A post-processing device that folds the paper S or performs stapling processing or the like on the paper S may be disposed on the downstream side of the pair of paper discharge rollers 25.

[Drive device for intermediate transfer belt]
Next, a driving device for the intermediate transfer belt 50 in the image forming apparatus 1 having the above configuration will be described.

  As shown in FIG. 1, the endless intermediate transfer belt 50 is stretched (strung) in a state where tension is applied to a plurality of rollers. The intermediate transfer belt 50 may meander while traveling, or may travel near one side (one side) in the belt width direction. For this reason, the drive device that is the drive unit of the intermediate transfer belt 50 is provided with a mechanism that prevents the intermediate transfer belt 50 from meandering and shifting (hereinafter referred to as “meandering prevention mechanism”).

  This meandering prevention mechanism uses a both-side regulating system that regulates the position in the belt width direction at both end portions of the intermediate transfer belt 50 and a position in the belt width direction at one side end portion of the intermediate transfer belt 50. There is a one-side regulation type. Which regulation type meandering prevention mechanism is adopted is arbitrary. That is, it can be arbitrarily selected according to the scale and grade of the image forming apparatus 1.

  The outline of these two regulation type meandering prevention mechanisms will be described with reference to FIG. In FIG. 2, (A) shows a meandering prevention mechanism of a both-side regulation type, and (B) shows a meandering prevention mechanism of a one-side regulation type.

<Both sides regulation method>
As shown in FIG. 2A, the both-side regulation type meandering prevention mechanism is a rib member (hereinafter referred to as “regulation rib”) provided along the side edge of the belt main body at both side ends of the back surface of the intermediate transfer belt 50. 100A and 100B, and restriction members (hereinafter, referred to as “regulation collars”) 120A and 120B disposed at both ends of the driven roller 110.

  The regulation ribs 100A and 100B are made of a rib member formed in a rod shape having a certain width (for example, about 5 mm) by a deformable material such as urethane rubber, and one rib member is belted inside the intermediate transfer belt 50. It is comprised by affixing with an adhesive etc. along the side edge of a main body. The regulation ribs 100A and 100B are attached to the intermediate transfer belt 50 by using, for example, a dedicated jig.

  The driven roller 110 is one of a plurality of rollers that stretch the intermediate transfer belt 50. The driven roller 110 and the restriction collars 120A and 120B are rotatably supported by a shaft 150 (see FIG. 3). The regulation collars 120 </ b> A and 120 </ b> B are formed so that the outer diameter thereof is smaller than the outer diameter of the driven roller 110 so as not to directly contact the intermediate transfer belt 50.

  This both-side regulation type meandering prevention mechanism regulates the position of the intermediate transfer belt 50 in the belt width direction in cooperation with the regulation ribs 100A and 100B and the regulation collars 120A and 120B. Prevent meandering and offset travel. More specifically, in the regulation collars 120A and 120B, the surfaces that come into contact with the regulation ribs 100A and 100B are tapered surfaces whose outer diameter increases toward the driven roller 110 side. When the intermediate transfer belt 50 is running, the inner edge ends of the regulation ribs 100A and 100B come into contact with the tapered surfaces of the regulation collars 120A and 120B, so that the position of the intermediate transfer belt 50 in the belt width direction is regulated.

  Here, when regulating the position of the intermediate transfer belt 50 in the belt width direction, the inner edge of the regulation ribs 100A and 100B rides on the tapered surfaces of the regulation ribs 100A and 100B, so that the end of the intermediate transfer belt 50 is bent. There is. Therefore, for the purpose of reinforcing the end of the intermediate transfer belt 50, PET (polyethylene terephthalate) is provided on both sides of the surface of the intermediate transfer belt 50 on the side opposite to the positions where the regulation ribs 100A and 100B are provided. Reinforcing materials 130 </ b> A and 130 </ b> B such as seals are attached along the rotation direction of the intermediate transfer belt 50.

<One side regulation method>
As shown in FIG. 2 (B), the meandering prevention mechanism of the one-side regulation type includes a regulation rib 100 provided along the side edge of the belt main body on the inner side of one side of the intermediate transfer belt 50, and a driven roller. 110 is provided with a regulation collar 120 having a drum-like shape, which is disposed at one end of 110.

  This one-side regulation type meandering prevention mechanism regulates the position of the intermediate transfer belt 50 in the belt width direction in cooperation with the drum-like regulation collar 120 and the regulation rib 100, thereby meandering the intermediate transfer belt 50. And prevent sideways travel. More specifically, the restriction collar 120 has two tapered surfaces, a tapered surface whose outer diameter increases toward the driven roller 110 and a tapered surface whose outer diameter increases toward the opposite side of the driven roller 110. It has a drum shape. When the intermediate transfer belt 50 is running, the outer edge or inner edge of the restriction rib 100 abuts one of the two tapered surfaces of the restriction collar 120, thereby restricting the position of the intermediate transfer belt 50 in the belt width direction. Done.

  As in the case of the both-side regulation type meandering prevention mechanism, for the purpose of reinforcing the end of the intermediate transfer belt 50, the regulation rib 100 is provided at the side end of the intermediate transfer belt 50 on the regulation rib 100 side. A reinforcing material 130A such as a PET seal is affixed to the side opposite to the position, and a reinforcing material 140A is affixed on the reinforcing material 130A for the purpose of further reinforcement.

[Intermediary transfer belt cleaning unit]
Next, the cleaning unit 53 of the intermediate transfer belt 50 in the image forming apparatus 1 having the above configuration will be described.

  3 to 5 show the configuration of the cleaning unit 53. Among these, FIG. 3 is a diagram showing an external configuration of the cleaning unit 53. 4 and 5 are diagrams showing the internal configuration of the cleaning unit 53 together with the intermediate transfer belt 50. FIG.

  As shown in FIGS. 4 and 5, the cleaning unit 53 includes a sheet material 531, a blade 532 (an example of a cleaning member), and a storage roller 533. As shown in FIG. 5, the cleaning unit 53 includes a side seal 534.

  The blade 532 is in sliding contact with the surface of the intermediate transfer belt 50 and removes toner remaining on the surface of the intermediate transfer belt 50. The storage roller 533 is in sliding contact with the surface of the intermediate transfer belt 50 on the upstream side (lower side in FIGS. 4 and 5) in the rotational direction of the intermediate transfer belt 50 with respect to the blade 532, and the toner removed by the blade 532. A part is stored in cooperation with the intermediate transfer belt 50. The stored toner is carried to the blade 532 again as the intermediate transfer belt 50 rotates, and plays a role of smoothing the sliding contact between the blade 532 and the intermediate transfer belt 50.

  The sheet material 531 is in the entrance portion of the intermediate transfer belt 50 in the cleaning unit 53 on the upstream side of the storage roller 533 in the rotation direction of the intermediate transfer belt 50 and in the width direction of the intermediate transfer belt 50 (lateral direction in FIG. 5). And is in contact with the surface of the intermediate transfer belt 50. A synthetic resin such as PET is used as the material of the sheet material 531. The side seals 534 are arranged along the longitudinal direction (vertical direction in FIG. 5) of the intermediate transfer belt 50 on the sides of both end portions of the sheet material 601. Although not shown, fine hair similar to the moquette material 603 shown in FIG. 8 is planted at a position facing the sheet material 531 in the side seal 534, and the sheet material 531 is the moquette material. In contact with hair. The sheet material 531 and the side seal 534 constitute a cleaning seal for preventing scattering of toner to the upstream side in the rotation direction of the intermediate transfer belt 50. A moquette material is also used for the material of the side seal 534 itself. The side seal 534 plays a role of preventing toner from scattering to the side of the intermediate transfer belt 50.

  As shown in FIG. 2, reinforcing materials (reinforcing materials 130A, 130B or reinforcing materials 130A, 130B, 140A, 140B) such as PET seals are attached to both ends of the surface of the intermediate transfer belt 50. In FIG. 5, these reinforcing materials are collectively shown as a reinforcing material 200. The position of the reinforcing material 200 in the width direction of the intermediate transfer belt 50 and the position of the sheet material 531 of the cleaning unit 53 are at positions facing each other with the intermediate transfer belt 50 interposed therebetween, and overlap each other.

  The start portion and the end portion of the reinforcement material 200 are overlapped, and a step (not shown) is generated in the overlap portion. As in the case shown in FIG. 9A, the reinforcing material 200 is attached so that the level difference of the overlapping portion does not collide with the sheet material 531 of the cleaning unit 53 when the intermediate transfer belt 50 rotates in the forward direction. Has been done. However, as a countermeasure when foreign matter is caught in the blade 532 of the cleaning unit 53, the image forming apparatus 1 slightly reverses the intermediate transfer belt 50 (2 to 8 mm) in the reverse direction at the end of the job or periodically. Rotate to During the rotation in the reverse direction, the stepped portion of the overlapping portion of the reinforcing material 200 comes into contact with and collides with the sheet material 531 of the cleaning unit 53 from the counter direction.

  As shown in FIG. 5, protruding portions 531 a that are portions protruding toward the side seal 534 are provided at both ends of the sheet material 531. FIG. 6 shows an enlarged shape of the protruding portion 531 a of the sheet material 531. The protruding portion 531 a has a tapered shape that is inclined to the upstream side in the rotation direction of the intermediate transfer belt 50 with respect to the longitudinal direction of the sheet material 531.

  As is clear by comparing FIG. 6 with FIG. 8 shown as the prior art, in the prior art, the sheet material of the cleaning unit does not overlap the side seal. On the other hand, the sheet material 531 of the cleaning unit 53 overlaps the side seal 534 by having protrusions 531a at both ends.

  As described above, by providing the protruding portion 531a protruding to the side seal 534 side, the step of the overlapping portion of the sheet material 531 and the reinforcing material 200 collides when the intermediate transfer belt 50 rotates in the reverse direction. However, the force received by the sheet material 531 due to the collision is weakened by the weight of the protruding portion 531a. In addition, since the protruding portion 531a has the inclined taper shape as described above, when the intermediate transfer belt 50 rotates in the reverse direction, the step of the overlapping portion of the sheet material 531 and the reinforcing material 200 is in point contact. To do. Also in this respect, the force received by the sheet material 531 due to the collision with the step of the overlapping portion of the reinforcing material 200 is weakened. As a result, bending of the sheet material 531 caused by contact between the step of the overlapping portion of the sheet material 531 and the reinforcing material 200 is reduced.

  As described above, according to the present embodiment, when the intermediate transfer belt 50 rotates in the reverse direction, the sheet material is caused by the collision between the sheet material 531 of the cleaning unit 53 and the step of the overlapping portion of the reinforcing material 200. The bending of 531 can be reduced. Accordingly, the sealing performance of the cleaning unit 53 can be ensured even when the intermediate transfer belt 50 rotates in the reverse direction, and the image can be prevented from being stained due to toner scattering.

[Modification]
The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention described in the claims.

  For example, in the above-described embodiment, the example in which the inclined tapered protrusions 531 a are provided at both ends of the sheet material 531 of the cleaning unit 53 has been described. However, as another example, as shown in FIG. 7, protrusions 531 b having a shape curved toward the upstream side in the rotation direction of the intermediate transfer belt 50 with respect to the longitudinal direction of the sheet material 531 at both ends of the sheet material 531. May be provided. Alternatively, the protrusions that are in a shape other than the protrusions 531a of FIG. 6 and the protrusions 531b of FIG. May be provided. Also in these cases, when the intermediate transfer belt 50 is rotated in the reverse direction, the step of the overlapping portion of the sheet material 531 and the reinforcing member 200 makes point contact, so that the collision with the step of the overlapping portion of the reinforcing member 200 occurs. Thus, the force received by the sheet material 531 can be weakened. As another example, the both ends of the sheet material 531 may be simply provided with portions protruding toward the side seal 534. Even in that case, as described above, the force received by the sheet material 531 due to the collision between the step of the overlapping portion of the sheet material 531 and the reinforcing material 200 can be weakened by the weight of the protruding portion.

  Further, in the above-described embodiment, the meandering of the intermediate transfer belt 50 is regulated by bringing the regulating members 120A, 120B into contact with the rib members 100A, 100B attached to the back surface of the intermediate transfer belt 50, and the intermediate transfer belt 50 The example in which the reinforcing members 130A, 130B, 140A, and 140B (the reinforcing member 200 in FIG. 5) are provided at the end portions of the surface has been described. However, the present invention is not limited to this, and a rib is not attached to the back surface of the intermediate transfer belt, but a regulating member is brought into contact with the side surface of the intermediate transfer belt to regulate meandering of the intermediate transfer belt, and at the end of the surface of the intermediate transfer belt. The present invention may be applied to an image forming apparatus provided with a reinforcing material.

  In the above-described embodiment, the example in which the surface of the intermediate transfer belt 50 is cleaned has been described. However, the present invention is not limited to this, and the present invention may be applied to an image forming apparatus that cleans the surface of a belt-like image carrier other than the intermediate transfer belt.

  For example, in the above-described embodiment, the example in which the image forming unit 40 is provided with the four image forming units 40Y, 40M, 40C, and 40K to form a color image has been described. However, a single color in which only one image forming unit is provided. The present invention may be applied to an image forming apparatus that forms an image.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Document conveying part, 20 ... Paper storage part, 21 ... Paper feeding part, 23 ... Conveying part, 30 ... Image reading part, 40 ... Image forming part, 40Y, 40M, 40C, 40K ... Image Forming unit 41 ... Photoconductor 50 ... Intermediate transfer belt 53 ... Cleaning unit 60 ... Secondary transfer part 70 ... Fixing part 100A, 100B ... Regulating rib 130A, 130B, 140A, 140B, 200 ... Reinforcing material 531 ... Sheet material, 531a, 531b ... Projection of sheet material, 532 ... Blade, 533 ... Storage roller, 534 ... Side seal

Claims (8)

A belt-like image carrier carrying toner on the surface;
Provided so as to have a portion superimposed me along the rotational direction of the image bearing member to the surface of the image bearing member, and a reinforcing member for reinforcing the image bearing member,
A cleaning member that is provided in the width direction of the image carrier and removes toner remaining on the surface of the image carrier;
A receiving member that is provided upstream of the cleaning member in the rotational direction of the image carrier and in the width direction of the image carrier, and that receives the toner removed by the cleaning member;
The receiving member has a protruding portion that collides with a portion where the reinforcing member is overlapped on a side in the width direction of the image carrier,
The protruding portion of the receiving member is an image forming apparatus formed so as to collide with a portion where the reinforcing member is overlapped by point contact . The image forming apparatus according to claim 1 , wherein the protruding portion of the receiving member has a tapered shape that is inclined upstream in the rotation direction of the image carrier. The image forming apparatus according to claim 2 , wherein the protruding portion of the receiving member has a curved shape that bends upstream in the rotation direction of the image carrier. 4. The image forming apparatus according to claim 1, wherein the reinforcing member has a tape shape and is attached to a surface of the image carrier so that a start portion and an end portion thereof overlap each other. The image forming apparatus according to claim 1, further comprising a side seal material provided adjacent to both end portions of the receiving member in the width direction of the image carrier. The image forming apparatus according to claim 5, wherein the side seal material overlaps the receiving member in a direction perpendicular to the surface of the image carrier. The image forming apparatus according to claim 5, wherein the side seal material is formed of a moquette material. The image forming apparatus according to claim 1, wherein a rib for preventing the image carrier from meandering is provided on a back surface of the image carrier.

Images