JP2012203098A - Belt unit, reinforcement member sticking method, validation method for belt unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt unit capable of increasing a meandering regulation force of an endless belt without forming a rib on an inner peripheral surface of the endless belt.SOLUTION: An intermediate transfer unit 10 is configured comprising an intermediate transfer belt 10e which can be stretched and rotated, a plurality rollers (10f to 10h) capable of stretching and rotating the intermediate transfer belt 10e and reinforcement members 46a and 46b which are stuck along at least one end in the belt width direction M on a face of the intermediate transfer belt 10e to reinforce the intermediate transfer belt 10e in a state where an energizing force T2 weaker than an energizing force T1, which is given to the intermediate transfer belt 10e when forming an image in an apparatus body 100A, is given to the intermediate transfer belt 10e through a tension roller 10h.

Description

  The present invention relates to a belt unit used in an image forming apparatus, a reinforcing member attaching method for attaching a reinforcing member for reinforcing an endless belt included in the belt unit, a belt unit verification method, and an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic system such as a printer, a copying machine, a facsimile, or an electrostatic recording system, an endless belt for transferring a toner image on an image carrier onto a transfer material is used. There is an image forming apparatus adopted. The endless belt includes an intermediate transfer member (intermediate transfer belt) that carries a toner image transferred from the image carrier, and a transfer material carrier that carries and conveys a transfer material that transfers the toner image from the image carrier. There is a body (transfer material conveyance belt). In an image forming apparatus provided with such an endless belt, it is necessary to regulate the deviation of the belt that occurs when the belt is driven. The term “belt shift” as used herein refers to movement in the belt width direction orthogonal to the belt conveyance direction.

  In order to regulate the deviation of the belt, the invention described in Patent Document 1 is disclosed. The invention described in Patent Document 1 relates to a configuration including a rib provided at an end portion of an inner peripheral surface of an endless belt in the belt width direction, and a tension roller that can contact the endless belt that contacts the rib. . According to such a configuration, when the endless belt approaches the longitudinal direction, the inner surface of the rib provided on the inner peripheral surface of the endless belt abuts against the end surface of the tension roller, thereby restricting the endless belt from shifting in the belt width direction. Is done.

  Further, the invention described in Patent Document 2 is disclosed in order to regulate the belt deviation even when the belt deviation force is larger than the rib deviation regulating force. The invention described in Patent Document 2 relates to a configuration in which a region that is an outer peripheral surface opposite to an inner peripheral surface of an endless belt provided with a rib and covers the entire joint surface of the endless belt is reinforced with a reinforcing member. According to such a configuration, the reinforcing member covers all the portions of the surface of the endless belt corresponding to the joining surface of the rib and the endless belt, so that the rigidity of the joining surface and the vicinity thereof can be increased, and the belt width of the endless belt. Direction deviation is regulated.

Japanese Patent Laid-Open No. 11-20975 JP 2005-156581 A

  However, as in the invention described in Patent Document 1, if it is attempted to regulate the deviation of the endless belt using only the ribs, the endless belt is likely to cause fatigue failure due to repeated stress applied to the endless belt.

  Specifically, it is as follows. In a state where the rib hits the stretching roller of the endless belt, a large stress acts on the joint surface between the rib and the endless belt. When the endless belt rotates, the place where the rib and the tension roller are in contact changes. At this time, the stress changes repeatedly. Such repeated changes in stress cause the endless belt to fatigue. That is, the endless belt breaks in the vicinity of the joint surface between the rib and the endless belt. In particular, if the composition is a resin-based material such as a transfer belt, fatigue failure is likely to occur. When this happens, it becomes impossible to regulate the endless belt.

  Further, as in the invention described in Patent Document 2, even if reinforcement is performed with a reinforcing member corresponding to a portion where the rib is provided, fatigue failure of the rib and the endless belt is reduced, but the above-described fatigue caused by the rib is reduced. Destruction can occur. When this happens, it becomes impossible to regulate the endless belt.

  In view of the above circumstances, an object of the present invention is to provide a belt unit that can increase the deviation regulating force of an endless belt without providing a rib on the inner peripheral surface of the endless belt.

  In order to solve the above-described problems, the belt unit of the present invention includes a rotatable endless belt, a plurality of rollers that are rotatable by stretching the endless belt, and the endless when the image forming apparatus main body forms an image. At least one of the surfaces of the endless belt in the belt width direction under a condition in which a biasing force weaker than a biasing force applied to the belt is applied to the endless belt through at least one of the plurality of rollers. And a reinforcing member that is attached along the end of the belt to reinforce the endless belt.

  The reinforcing member sticking method of the present invention is a reinforcement in which a reinforcing member that reinforces the endless belt is attached to at least one end in the belt width direction of the surface of the endless belt that is stretched and rotated by a plurality of rollers. In the member sticking method, an urging force weaker than an urging force applied to the endless belt when the endless belt is attached to the image forming apparatus main body is transmitted via at least one of the plurality of rollers. The reinforcing member is attached to the endless belt in a state of being applied to the endless belt.

  According to the present invention, it is possible to increase the deviation regulating force of the endless belt without providing a rib on the inner peripheral surface of the endless belt.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus including an intermediate transfer unit according to an embodiment of the present invention. FIG. 3 is a perspective view illustrating a configuration of an intermediate transfer unit. It is an expansion perspective view which shows the structure of the vicinity of a tension roller. FIG. 2 is a cross-sectional view showing a schematic configuration of an intermediate transfer unit. FIG. 6 is a cross-sectional view showing a state of the intermediate transfer belt while the reinforcing member attaching device is attaching the reinforcing member. FIG. 6 is a cross-sectional view showing a state of the intermediate transfer belt before the reinforcing member attaching device attaches the reinforcing member. FIG. 3 is a partially enlarged plan view showing a schematic configuration in the vicinity of a tension roller when an intermediate transfer belt to which a reinforcing member is attached is stretched around a reinforcing member attaching device. FIG. 2 is a partially enlarged plan view showing a schematic configuration in the vicinity of a tension roller when an intermediate transfer belt to which a reinforcing member is attached is stretched inside the apparatus main body. FIG. 2 is a cross-sectional view showing a schematic configuration of an intermediate transfer unit.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, there is no specific description. As long as the scope of the invention is not limited to these, it is not intended.

  FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus 100 including an intermediate transfer unit 10 according to Embodiment 1 of the present invention. Here, the image forming apparatus 100 is a color laser beam printer having a double-sided printing function using an electrophotographic image forming process. As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 100 </ b> A. 51d is provided.

  The image forming units 51a to 51d include photosensitive drums 1a to 1d that are “image carriers”, primary transfer rollers 10a to 10d that are “transfer devices”, and the like. At least the photosensitive drums 1a to 1d may be included in the cartridges 3a to 3d and may be incorporated into the apparatus main body 100A as the cartridges 3a to 3d. The image forming apparatus 100 has a configuration in which an optional feeding device (hereinafter referred to as a feeding option unit) 90 is added below the apparatus main body 100A.

  The image forming apparatus 100 includes four process cartridges (hereinafter referred to as “cartridges”) 3a to 3d that are detachable inside the apparatus main body 100A. Although the cartridges 3a to 3d have the same structure, different color toners are stored in the cartridges 3a to 3d, and images of different colors are formed. That is, the cartridge 3a forms a yellow (Y) toner image. The cartridge 3b forms a magenta (M) toner image. The cartridge 3c forms a cyan (c) toner image. The cartridge 3d forms a black (Bk) toner image.

  Each of the cartridges 3a, 3b, 3c, and 3d includes developing units 4a, 4b, 4c, and 4d, and cleaner units 5a, 5b, 5c, and 5d for developing each color toner image. The developing units 4a, 4b, 4c, and 4d include developing rollers 6a, 6b, 6c, and 6d, developer application rollers 7a, 7b, 7c, and 7d, and a toner container. The cleaner units 5a, 5b, 5c, and 5d are photosensitive drums 1a, 1b, 1c, and 1d as image carriers, charging rollers 2a, 2b, 2c, and 2d, drum cleaning blades 8a, 8b, 8c, and 8d, And a waste toner container.

  A scanner unit 9 is disposed below the cartridges 3a to 3d. The scanner unit 9 performs exposure based on the image signal to the photosensitive drums 1a, 1b, 1c, and 1d.

  The photosensitive drums 1a, 1b, 1c, and 1d are charged to a predetermined negative potential by the charging rollers 2a, 2b, 2c, and 2d, and then electrostatic images (electrostatic latent images) are formed by the scanner unit 9, respectively. Is done. This electrostatic image is reversed and developed by the developing units 4a, 4b, 4c, and 4d, and negative toner is attached to form toner images of Y, M, C, and Bk, respectively.

  An intermediate transfer belt unit (hereinafter referred to as “intermediate transfer unit 10”) is disposed above the cartridges 3a to 3d. The intermediate transfer unit 10 includes an intermediate transfer belt 10e, a driving roller 10f that stretches the intermediate transfer belt 10e, a counter roller 10g, and a tension roller 10h. A biasing force T indicated by an arrow in FIG. 1 is applied to the intermediate transfer belt 10e by a tension roller 10h. Further, primary transfer rollers 10a, 10b, 10c, and 10d are disposed inside the intermediate transfer belt 10e at positions facing the photosensitive drums 1a, 1b, 1c, and 1d, respectively. A transfer bias is applied to the primary transfer rollers 10a to 10d by a bias applying unit (not shown).

  The toner images formed on the photosensitive drums 1a to 1d are sequentially primary transferred onto the intermediate transfer belt 10e. At this time, each of the photosensitive drums 1a to 1d rotates clockwise. Further, the intermediate transfer belt 10e rotates counterclockwise. Toner images are transferred onto the surface of the intermediate transfer belt 10e in order from the photosensitive drums 1a to 1d on the upstream side in the rotation direction. Transfer of the toner image from the photosensitive drums 1a to 1d to the intermediate transfer belt 10e is performed by applying a positive bias to the primary transfer rollers 10a to 10d. Thus, the toner image formed in a state where the four color toner images are superimposed on the intermediate transfer belt 10 e moves to the secondary transfer unit 13.

  On the other hand, after the toner image is transferred, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning blades 8a to 8d. Further, the toner remaining on the intermediate transfer belt 10 e after the secondary transfer onto the sheet S is removed by the transfer belt cleaning device 11. The removed toner passes through a waste toner conveyance path (not shown) and is collected in a waste toner collection container (not shown).

  The image forming apparatus 100 includes three sheet feeding devices (sheet feeding units). The first is a main body sheet feeding unit 20 disposed inside the apparatus main body 100A. The second is a multi-sheet feeding unit 30 disposed on the side surface of the apparatus main body 100A. The third is an optional feeding device 90 added below the apparatus main body 100A.

  The first main body sheet feeding unit 20 includes a feeding roller 22 that feeds the sheet S from the inside of the feeding cassette 21 that stores the sheet S, and a separation roller 23 that is a separation unit. The sheets S stored in the feeding cassette 21 are pressed against the feeding roller 22 and separated and conveyed one by one by the separation roller 23. The separated sheet S is conveyed to the registration roller pair 14 via the conveyance path 24.

  The second multi-sheet feeding unit 30 includes a middle plate 31 on which the sheets S are stacked, a multi-feed roller 32 that feeds the sheets S stacked on the middle plate 31, and a separation pad 33 that is a separation unit. Have. The intermediate plate 31 is lifted, and the sheets S stacked on the intermediate plate 31 are pressed against the multi-feed roller 32 and separated and conveyed one by one by the separation pad 33. The separated sheet S is conveyed to the refeed roller pair 35 via the multi-feed conveyance path 34.

  The sheet conveyed to the refeed roller pair 35 passes through the refeed conveyance path 36 and is conveyed to the registration roller pair 14. Note that the re-feed roller pair 35 and the re-feed conveyance path 36 become a common conveyance path during double-sided conveyance as will be described later.

  The third optional feeding device 90 includes a pickup roller 91, a feed roller 92, and a retard roller 93. By the cooperation of the pickup roller 91, the feed roller 92, and the retard roller 93, the sheets are fed one by one from the stacked sheet bundle, separated and conveyed. The conveyed sheet passes the relay conveying roller pair 94 and the optional discharge roller pair 95, and conveys the sheet S to the secondary transfer unit 13 of the apparatus main body 100A. The sheet S conveyed from the option feeding device 90 is conveyed to the registration roller pair 14 via the option feeding conveyance path 96.

  As described above, on the upstream side of the registration roller pair 14 of the apparatus main body 100A, the three conveying paths are joined.

  The secondary transfer unit 13 transfers the toner image formed on the intermediate transfer belt 10 e to the sheet S. The secondary transfer unit 13 includes a secondary transfer roller 13a to which a positive bias is applied. By applying a positive bias to the secondary transfer unit 13, the four color toner images on the intermediate transfer belt 10 e are secondarily transferred to the sheet S conveyed by the registration roller pair 14.

  Above the secondary transfer unit 13, a fixing device 15 having a fixing roller 15a and a pressure roller 15b is provided. The sheet S on which the toner image is transferred is conveyed to the nip between the fixing roller 15a and the pressure roller 15b, heated and pressed by the fixing roller 15a and the pressure roller 15b, and transferred to the surface of the sheet S. The toner image that has been stored is fixed.

  Above the fixing device 15, a switching member 16, a discharge roller pair 17 and a switchback roller pair 19 are provided. The transport path of the fixed sheet S is selectively switched depending on the position of the switching member 16 depending on whether the single-sided printing or the double-sided printing selected in advance.

  When single-sided printing is selected, the fixed sheet S is guided toward the discharge roller pair 17 by the switching member 16. The sheet guided by the discharge roller pair 17 is discharged onto the tray 18 which is the upper surface of the apparatus main body 100A.

  When duplex printing is selected, the switching member 16 guides the switchback roller pair 19. Here, the switchback roller pair 19 conveys the sheet S toward the tray 18, and then reversely rotates at the timing when the trailing end of the sheet S exits the fixing device 15, thereby conveying the sheet S to the double-sided reverse conveyance path 37. . At the same time as the switchback roller pair 19 rotates in the reverse direction, the switching member 16 moves to guide the sheet S to the double-side reverse conveyance path 37.

  The duplex conveying roller pair 38 conveys the sheet to the refeed roller pair 35. The sheet S re-fed by the re-feed roller pair 35 joins the re-feed conveyance path 36 in a state where the front and back sides are reversed and is conveyed to the registration roller pair 14 again. The conveyance of the sheet and the transfer of the toner image after the registration roller pair 14 are the same as in the above-described single-side printing.

  FIG. 2 is a perspective view showing the configuration of the intermediate transfer unit 10. As shown in FIG. 2, the intermediate transfer unit 10 that is a “belt unit” includes a driving roller 10 f, a counter roller 10 g, and a tension roller 10 h that are a plurality of rollers arranged in parallel to each other. The intermediate transfer unit 10 is an intermediate transfer belt 10e that is an “endless belt” that is stretched around a plurality of rollers (10f to 10h) and is rotatable in the belt rotation direction b by the rotation of the plurality of rollers (10f to 10h). Have

  The base layer of the intermediate transfer belt 10e is made of a resin material having high tensile strength such as polyimide (PI), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), polyether ether ketone (PEEK). Due to requirements such as molding, strength, and ease of deformation, the base layer is often made between 50 μm and 100 μm in thickness. There is also an intermediate transfer belt 10e having a multilayer structure in which different layers such as a rubber layer are bonded to the entire outer peripheral surface of the base layer in order to increase the efficiency of toner transfer. The intermediate transfer belt 10e may have any of these compositions.

  Further, the intermediate transfer belt 10e includes reinforcing members 46a and 46b over the entire circumference of both ends of the outer peripheral surface (surface). Specifically, the reinforcing members 46a and 46b are attached along at least one end of the intermediate transfer belt 10e in the belt width direction M orthogonal to the belt rotation direction b to reinforce the intermediate transfer belt 10e. At this time, an urging force T2, which is weaker than the urging force T1 applied to the intermediate transfer belt 10e during image formation in the apparatus main body 100A, passes through the tension roller 10h, which is “at least one roller of a plurality of rollers”. It is in a state of being applied to the intermediate transfer belt 10e (described later). This reinforcing member attaching method will be described later.

  The reinforcing members 46a and 46b may have a width of 2 to 3 mm or more, and may be any number as long as space is allowed. The thickness is not limited as long as the thickness is 10 μm or more. Further, the reinforcing member 46a and the reinforcing member 46b may have different widths and thicknesses, or may be formed of different materials.

  For the reinforcing members 46a and 46b, a film adhesive tape made of a resin material such as polyester or polyimide is used. Alternatively, on the reinforcing members 46a and 46b, films such as polyimide (PI), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK) are used as in the base layer of the intermediate transfer belt 10e. Use adhesive tape. Basically, any material can be used as long as it has sufficient tensile strength. Further, as long as it can be molded integrally with the intermediate transfer belt 10e, it may be used.

  The higher the tensile strength of the reinforcing members 46a and 46b, the higher the effect of the belt shift restriction according to the present invention. However, if the intermediate transfer belt 10e is relatively hard, the effect of the present invention is reduced. Therefore, when the tensile strength of the reinforcing members 46a and 46b is low, or when the material of the intermediate transfer belt 10e is very hard, the reinforcing members 46a and 46b are made of a material having as high a tensile strength as possible with a certain width and height. You must prepare. Actually, it is practical to use a material having a Young's modulus comparable to that of the intermediate transfer belt 10e, a thickness of 20 to 50 μm, and a width of about several mm.

  The intermediate transfer belt 10e (the central portion is partially sectioned) is stretched around a driving roller 10f, a counter roller 10g, and a tension roller 10h, which are a plurality of stretching members for stretching the intermediate transfer belt 10e.

  The driving roller 10f, the opposing roller 10g, and the tension roller 10h are rotatably supported by bearings 40, 41, and 42 at both ends in the longitudinal direction, respectively. The main frame 43 (43a, 43b) of the intermediate transfer belt 10e supports the bearings 40, 41, and the support side plate 44 of the tension roller 10h supports the bearing 42. A spring fixing portion 52 is provided on a side plate 43a of the intermediate transfer belt main frame (hereinafter referred to as “main frame 43”). One end of a tension roller spring 45 is fixed to the spring fixing portion 52, and the tension roller spring 45 biases the support side plate 44 in a biasing direction (a direction in which the spring extends).

  The drive roller 10 f is a fixed roller supported by the main frame 43 via the bearing 40. Driving force is transmitted to the driving roller 10f from driving means (not shown) of the apparatus main body 100A. The driving roller 10f to which the driving force is transmitted rotates to drive and convey the intermediate transfer belt 10e. The surface of the driving roller 10f is formed of a rubber layer having a high friction coefficient in order to convey the intermediate transfer belt 10e without slipping.

  The facing roller 10 g is a fixed roller supported by the main frame 43 via a bearing 41. The opposing roller 10g forms a nip with the secondary transfer roller 13a, and transfers the toner image onto the sheet S while nipping and conveying the sheet S. The counter roller 10g is driven to rotate by driving and conveying the intermediate transfer belt 10e.

  The tension roller 10 h is supported by the main frame 43 through a bearing 42 so as to be slidable together with the support side plate 44.

  FIG. 3 is an enlarged perspective view showing a configuration in the vicinity of the tension roller 10h. The “sliding operation of the tension roller 10h” and the “configuration for stretching the intermediate transfer belt 10e” will be described below with reference to FIG. As shown in FIG. 3, an opening 44 c is formed in the support side plate 44. Boss portions 43c and 43d formed on the main frame 43 are inserted into the opening 44c. Thereby, the support side plate 44 is supported by the main frame 43.

  The opening width 44d of the opening 44c is configured to be wider than the outer diameter width 43e formed by the boss portions 43c and 43d. The support side plate 44 can be slid by the amount of play of the opening width 44d and the outer diameter width 43e. That is, the tension roller 10h can slide.

  Tension roller springs 45, which are compression springs, are provided on the front side and the back side of the intermediate transfer unit 10, respectively. The tension roller spring 45 urges the support side plate 44, that is, the tension roller 10h in the direction of arrow a to apply tension to the intermediate transfer belt 10e. When the urging force of the tension roller spring 45 and the tension of the intermediate transfer belt 10e are balanced, the tension roller 10h is locked.

  Next, a method for attaching the reinforcing members 46a and 46b to the intermediate transfer belt 10e will be described in detail with reference to FIGS.

  FIG. 4A is a cross-sectional view illustrating a schematic configuration of the intermediate transfer unit 10. As shown in FIG. 4A, the intermediate transfer belt 10e receives a biasing force T1 from the tension roller spring 45 when the intermediate transfer belt 10e is attached to the apparatus main body 100A. The urging force T1 is a tension applied to the intermediate transfer belt 10e when the apparatus main body 100A forms an image. This is because when the primary transfer rollers 10a to 10d primarily transfer the toner images on the photosensitive drums 1a to 1d to the intermediate transfer belt 10e, or the secondary transfer unit 13 transfers the toner images on the intermediate transfer belt 10e to a sheet. This is an urging force applied to the intermediate transfer belt 10e when secondary transfer is performed to S.

  FIG. 4B is a cross-sectional view showing the state of the intermediate transfer belt 10e before the reinforcing member attaching apparatus 101 attaches the reinforcing members 46a and 46b. The reinforcing member affixing device 101 includes three rollers (101a, 101b, 101c) shown in FIG. 4B and a spring 101d as an urging force applying means. It has the drive means etc. of illustration. The reinforcing member sticking device 101 is a device for sticking the reinforcing members 46a and 46b to the intermediate transfer belt 10e.

  The three rollers (101a, 101b, 101c) are made of the same material and outer diameter as the driving roller 10f, counter roller 10g, and tension roller 10h provided in the intermediate transfer unit 10. This is because the correlation between the apparatus main body 100A and the reinforcing member sticking apparatus 101 is improved when the apparatus is as close as possible to the conditions of the apparatus main body 100A.

  For example, if the conditions of the three rollers of the reinforcing member affixing device 101 and the conditions of the three rollers of the intermediate transfer unit are approximate, the following can be performed. That is, the reinforcing members 46a and 46b can be attached to the intermediate transfer belt 10e while considering what conveyance speed can be driven when the intermediate transfer belt 10e is incorporated in the apparatus main body 100A.

  The driving roller 101a drives and conveys the intermediate transfer belt 10e stretched around the reinforcing member sticking device 101. In other cases, the intermediate transfer belt 10e is stretched between a tension roller 101b and a tension roller 101c.

  The tension roller 101c is applied with a biasing force T2 from the spring 101d, and applies a biasing force T2 to the intermediate transfer belt 10e. The biasing force T2 applied by the spring 101d is set to a biasing force that is weaker than the biasing force T1 described above.

  Specifically, for example, the urging force T1 is equivalent to a total urging force of 10 kgf with two 5 kgf springs, and is applied to the intermediate transfer belt 10 e via the tension roller 10 h. On the other hand, for example, the urging force T2 is equivalent to a total urging force of 6 kgf with two 3 kgf springs, and is applied to the intermediate transfer belt 10e via the tension roller 101c.

  FIG. 5A is a cross-sectional view showing a state of the intermediate transfer belt 10e while the reinforcing member attaching device 101 is attaching the reinforcing members 46a and 46b. FIG. 5B is a cross-sectional view showing a state of the intermediate transfer belt 10e after the reinforcing member attaching apparatus 101 has attached the reinforcing members 46a and 46b. As shown in FIG. 5A, in order to attach the reinforcing members 46a and 46b to the intermediate transfer belt 10e, first, the intermediate transfer belt 10e is hung on three rollers (101a, 101b, and 101c). Then, the biasing force T2 is applied to the intermediate transfer belt 10e via the tension roller 101c by the spring 101d.

  Next, the reinforcing members 46a and 46b are attached to both ends of the intermediate transfer belt 10e in the belt width direction M by a reinforcing member attaching means (not shown). The driving roller 101a is rotated in the belt rotation direction b by a driving unit (not shown), and the intermediate transfer belt 10e is driven and conveyed in the same direction. The intermediate transfer belt 10e being driven and conveyed winds up the reinforcing members 46a and 46b from a reinforcing member attaching means (not shown). When the intermediate transfer belt 10e is driven and conveyed for more than one round, the driving means (not shown) stops driving. Then, sticking of the reinforcing members 46a and 46b to the intermediate transfer belt 10e is completed (see FIG. 5B).

  FIG. 6A is a cross-sectional view showing a state of the intermediate transfer belt 10e before the reinforcing member attaching apparatus 101 ′ attaches the reinforcing members 46a and 46b. The reinforcing member affixing device 101 ′ does not necessarily have the same configuration as the actual machine. That is, it is not necessary to be configured under the same conditions as those for the apparatus main body 100A that is actually incorporated. A reinforcing member sticking device 101 ′ having a shape different from that of the reinforcing member sticking device 101 will be described with reference to FIGS. 6 (a) to 6 (c).

  A reinforcing member sticking device 101 ′ shown in FIG. 6A is a device for sticking the reinforcing members 46a and 46b to the intermediate transfer belt 10e. The reinforcing member sticking apparatus 101 ′ includes two rollers (101a ′, 101c ′), a spring 101d ′, a reinforcing member sticking means (not shown), a driving means (not shown), and the like.

  The driving roller 101a ′ drives and conveys the intermediate transfer belt 10e stretched around the reinforcing member sticking device 101 ′. The tension roller 101c ′ is applied with a biasing force T2 from the spring 101d ′, and applies a biasing force to the intermediate transfer belt 10e. The biasing force T2 applied by the spring 101d ′ is set to a biasing force that is weaker than the biasing force T1 described with reference to FIG.

  Specifically, for example, the urging force T1 is equivalent to a total urging force of 10 kgf with two 5 kgf springs, and is applied to the intermediate transfer belt 10 e via the tension roller 10 h. On the other hand, for example, the urging force T2 is equivalent to a total urging force of 6 kgf with two 3 kgf springs, and is applied to the intermediate transfer belt 10e via the tension roller 101c '.

  FIG. 6B is a cross-sectional view showing a state in which the reinforcing member attaching device 101 ′ is attaching the reinforcing members 46a and 46b to the intermediate transfer belt. FIG. 6C is a cross-sectional view showing a state where the reinforcing member attaching apparatus 101 ′ has attached the reinforcing members 46a and 46b to the intermediate transfer belt 10e. As shown in FIG. 6B, the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e as follows. First, the intermediate transfer belt 10e is hung on the two rollers (101a 'and 101c'), and the biasing force T2 is applied by the spring 101d 'to stretch the intermediate transfer belt 10e.

  Next, reinforcing members 46a and 46b are attached to both ends in the longitudinal direction of the intermediate transfer belt 10e by means of a reinforcing member attaching means (not shown). The driving roller 101a ′ is rotated in the belt rotation direction c by a driving unit (not shown), and the intermediate transfer belt 10e is driven and conveyed in the same direction. The intermediate transfer belt 10e being driven and conveyed winds up the reinforcing members 46a and 46b from a reinforcing member attaching means (not shown). When the intermediate transfer belt 10e is driven and conveyed for more than one round, the driving means (not shown) stops driving. The intermediate transfer belt 10e winds around the reinforcing members 46a and 46b that are slightly more than one turn of the intermediate transfer belt 10e, and the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e (see FIG. 6C).

  Next, referring to FIGS. 7A, 7B, 8A, and 8B, a mechanism for increasing the rigidity of the portion where the reinforcing members 46a and 46b are attached will be described below. .

  7A is a partially enlarged plan view showing a schematic configuration in the vicinity of the tension roller 101c when the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are attached is stretched around the reinforcing member attaching apparatus 101. FIG. It is. FIG. 7B shows the tension at each location in the belt width direction M of the intermediate transfer belt 10e when the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are attached is stretched around the reinforcing member attaching device 101. It is a graph showing distribution.

  7A and 7B, positions A, B, C, D, and E are positions where a load sensor or a pressure sensor for measuring the tension of the intermediate transfer belt 10e is provided. Specifically, with reference to the belt width direction M, the position A and the position E are in the vicinity of the middle of the reinforcing members 46a and 46b provided at both ends of the intermediate transfer belt 10e, and the position C is the position A and the position A. In the middle of E, position B is in the middle of positions A and C, and position D is in the middle of positions C and E.

  As shown in FIG. 7A, reinforcing members 46a and 46b are affixed to the intermediate transfer belt 10e, and an urging force T2 × 2 is applied via a tension roller 101c by a spring 101d. The tension distribution is as shown in FIG.

  The reason why the tension distribution of the intermediate transfer belt 10e is as shown in FIG. 7B will be described below. While the urging force T2 × 2 is applied to the intermediate transfer belt 10e and is stretched around the reinforcing member affixing device 101, the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e without applying tension. Yes. Therefore, even after the reinforcing members 46a and 46b are attached, the tension of the intermediate transfer belt 10e is substantially the same in each of the positions A to E.

  FIG. 8A is a partially enlarged plan view showing a schematic configuration in the vicinity of the tension roller 10h when the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are attached is stretched inside the apparatus main body 100A. It is. FIG. 8B shows a tension distribution at each location in the belt width direction M of the intermediate transfer belt 10e when the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are attached is stretched in the apparatus main body 100A. It is the graph showing.

  Here, the reinforcing member affixing device 101 affixes the reinforcing members 46a and 46b to the intermediate transfer belt 10e, and this intermediate transfer belt 10e is attached to the apparatus main body 100A. The intermediate transfer belt 10e is provided with a roller (10h) by a spring (45). ), The biasing force T1 × 2 is applied. Since the force relationship between the urging force T1 and the urging force T2 is a relationship of T1> T2, the intermediate transfer belt 10e receives the urging force more than when the reinforcing members 46a and 46b are pasted. If it does so, the tension | tensile_strength of the intermediate transfer belt 10e of the edge part which stuck the reinforcement members 46a and 46b and became rigid will become strong.

  In other words, a force that causes the intermediate transfer belt 10e to be stepped on with respect to a shifting force in the belt width direction M that is orthogonal to the belt conveyance direction L is generated, so that the intermediate transfer belt 10e can be stably driven. It becomes. Further, since the end portion of the intermediate transfer belt 10e can be reinforced by the reinforcing members 46a and 46b, it is also effective for tearing cracks from the end portions.

  In other words, whether or not it has been created using the present invention can be understood by performing a verification reverse to the order described above (belt unit verification method). For example, an urging force T1 attached to the apparatus main body 100A and applied during image formation is applied to the intermediate transfer belt 10e. Then, the tension of the intermediate transfer belt 10e is measured. As a result, the tension at the five positions A to E shown in FIG. 8A is higher at the end than at the center as shown in FIG. 8B. In other words, this state is as follows. When the urging force applied to the intermediate transfer belt 10e is the urging force T1 applied during image formation, the tension X1 in the region where the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e is reinforced to the intermediate transfer belt 10e. It is stronger than the tension x1 in the region where the members 46a and 46b are not attached.

  Next, when the urging force applied to the intermediate transfer belt 10e is weakened, the tension of the intermediate transfer belt 10e is changed to the center at the end as shown in FIG. The parts are also the same. A configuration that follows such a change in tension uses the present invention. If the situation in FIG. 7B is expressed in another way, the situation is as follows. That is, the urging force applied to the intermediate transfer belt 10e is made weaker than the urging force T1 applied during image formation (the urging force T2 is set). Then, the tension X2 in the region where the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e becomes substantially the same as the tension x2 in the region where the reinforcing members 46a and 46b are not attached to the intermediate transfer belt 10e.

  Further, another method for verifying whether or not the present invention is used will be described in detail with reference to FIGS. 9A and 9B. FIG. 9A is a cross-sectional view illustrating a schematic configuration of the intermediate transfer unit 10. FIG. 9B is a cross-sectional view illustrating a schematic configuration in which the reinforcing members 46 a and 46 b are removed from the intermediate transfer unit 10.

  9 (a) and 9 (b), when the urging force T2 applied during image formation is applied to the intermediate transfer unit 10 illustrated in FIGS. 9 (a) and 9 (b), the tension roller 10h There is a shift (Δ) in position between the two. This is because the intermediate transfer unit 10 illustrated in FIG. 9B is less rigid than the intermediate transfer unit 10 illustrated in FIG. 9A because the reinforcing members 46a and 46b are not provided. It is.

  If the urging force applied to the intermediate transfer belt 10e during image formation is the same as the urging force when the reinforcing members 46a and 46b are attached to the intermediate transfer belt 10e, the reinforcing members 46a and 46b may be attached. Even if it peels off, the position of the tension roller 10h hardly changes.

  Such a configuration that follows the change in the pitch between the rollers uses the present invention. In other words, the change in pitch is verified by the following belt unit verification method. For example, one roller (tension roller 10h) that stretches the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are attached under the conditions of the present invention when an urging force that is applied during image formation is applied. Let Z1 be the distance to move in the direction of the urging force. On the other hand, the distance that one roller (tension roller 101c) that stretches the intermediate transfer belt 10e to which the reinforcing members 46a and 46b are not attached under the conditions of the present invention moves in the urging force direction is Z2. In this case, the intermediate transfer belt 10e is verified using the property that Z1 is shorter than Z2.

  According to the above-described embodiment, the intermediate transfer belt 10e is in a state in which the urging force T2 that is weaker than the urging force T1 applied to the intermediate transfer belt 10e during image formation in the apparatus main body 100A is applied to the intermediate transfer belt 10e. Then, the reinforcing members 46a and 46b are affixed to have a portion having high rigidity. Further, the intermediate transfer belt 10e has a portion where the reinforcing members 46a and 46b are not attached. Thus, a rigidity difference is set for the intermediate transfer belt 10e. As a result, it is possible to increase the deviation regulating force of the intermediate transfer belt 10e without providing ribs on the inner peripheral surface of the intermediate transfer belt 10e.

  In the prior art, in order to reduce the offset force of the endless belt, the product cost and the manufacturing cost are increased by increasing the component accuracy, providing a special mechanism, and using a special tool. In order to reduce these, an inexpensive and easy attachment method for attaching the reinforcing member to the endless belt with an appropriate setting is required. Then, when the endless belt is stretched around the roller, a method has been considered in which the length of the endless belt and the reinforcing member in the flat portion is the same.

  In the case of this method, the location where the reinforcing member is attached to the endless belt is limited to the location that is flat when the endless belt is stretched. For this reason, there is a manufacturing restriction at the location where the reinforcing member is pasted. In addition, since the endless belt and the length of the reinforcing member are the same at the planar portion, there is a possibility that the rigidity of the endless belt cannot be sufficiently increased with respect to the allowable belt shifting force. In consideration of this, it can be said that the life of the intermediate transfer belt 10e can be increased, and the deviation regulating force of the intermediate transfer belt 10e can be increased without requiring a complicated manufacturing process at a low cost and in a small space. .

  In the embodiment, the intermediate transfer unit 10 is exemplified as the configuration of the belt unit described above, but the configuration is not limited thereto. That is, the configuration of the belt unit can be applied to a secondary transfer belt, a transfer material carrier, and the like, and can also be applied to other mechanisms for conveying a transfer material.

10 Intermediate transfer unit (belt unit)
10e Intermediate transfer belt (endless belt)
10f Drive roller (roller)
10g Opposing roller (roller)
10h Tension roller (roller)
46a, 46b Reinforcing member 100A apparatus main body (image forming apparatus main body)
b Belt rotation direction T1 biasing force T2 biasing force

Claims (7)

A rotatable endless belt,
A plurality of rollers capable of rotating by stretching the endless belt;
A condition in which an urging force weaker than an urging force applied to the endless belt when an image is formed by the tension image forming apparatus main body is applied to the endless belt through at least one of the plurality of rollers. And a reinforcing member that is affixed along at least one end of the surface of the endless belt in the belt width direction and reinforces the endless belt,
A belt unit comprising: When the urging force applied to the endless belt is the urging force applied during image formation, the tension in the region where the reinforcing member is applied to the endless belt is not applied to the endless belt. Stronger than the tension of the area,
When the urging force applied to the endless belt is made weaker than the urging force applied at the time of image formation, the tension in the region where the reinforcing member is attached to the endless belt is such that the reinforcing member is applied to the endless belt. The belt unit according to claim 1, wherein the belt unit becomes substantially the same as the tension of the non-attached region. When the urging force applied during image formation is applied,
The distance that one of the rollers that stretch the endless belt to which the reinforcing member is attached under the above conditions moves in the direction of the urging force is:
3. The belt unit according to claim 1, wherein one of the rollers that stretch the endless belt to which the reinforcing member is not attached under the condition is shorter than a distance in which the roller moves in a biasing force direction. . A reinforcing member affixing method for affixing a reinforcing member that reinforces the endless belt to at least one end in a belt width direction of a surface of an endless belt that is stretched and rotated by a plurality of rollers,
A biasing force that is weaker than a biasing force applied to the endless belt when the endless belt is attached to the image forming apparatus main body is applied to the endless belt through at least one of the plurality of rollers. A reinforcing member attaching method, wherein the reinforcing member is attached to the endless belt in a state. A belt unit verification method for a belt unit according to any one of claims 1 to 3, or a belt unit created by the reinforcing member affixing method according to claim 4,
When the urging force applied to the endless belt is the urging force applied during image formation, the tension in the region where the reinforcing member is applied to the endless belt is not applied to the endless belt. Stronger than the tension of the area,
When the urging force applied to the endless belt is made weaker than the urging force applied at the time of image formation, the tension in the region where the reinforcing member is attached to the endless belt is such that the reinforcing member is applied to the endless belt. A belt unit verification method that verifies the configuration of the belt unit by utilizing the property that it becomes substantially the same as the tension of the unattached region. A belt unit verification method for a belt unit according to any one of claims 1 to 3, or a belt unit created by the reinforcing member affixing method according to claim 4,
When the urging force applied during image formation is applied,
The distance that one of the rollers that stretch the endless belt to which the reinforcing member is attached under the above conditions moves in the direction of the urging force is:
A belt unit verification method that verifies the configuration of the belt unit by utilizing the property that one of the rollers that stretch the endless belt to which the reinforcing member is not attached is shorter than the distance that it moves in the urging force direction under the above conditions. . An image forming unit for forming an image;
A belt unit according to any one of claims 1 to 3, or a belt unit created by the reinforcing member attaching method according to claim 4,
An image forming apparatus comprising:

Images