Belt conveying device and image forming apparatus

Abstract

To provide a belt conveying device that facilitates replacement of a component and can suitably maintain a performance of stopping meandering of a belt.SOLUTION: A correction mechanism 50 of a belt conveying device 40 comprises a pair of inclined bearings 52 and a pair of body guides 54, and corrects meandering of an intermediate transfer belt 41. The pair of inclined bearings 52 have a pair of bearing parts 521, and a pair of inclined parts 522 that are inclined symmetrically with respect to an axial direction Dx of a tension roller 43. The pair of body guides 54 are in contact with the pair of inclined parts 522, and when the intermediate transfer belt 41 meanders, move one end side in the axial direction Dx of the tension roller 43 in a direction orthogonal to the axial direction Dx together with the pair of inclined bearings 52. The pair of inclined bearings 52 are removably attached to a shank 431 of the tension roller 43.SELECTED DRAWING: Figure 20

Description

[Technical field]

[0001] The present invention relates to a belt conveying device and an image forming apparatus. [Background technology]

[0002] A belt conveying device is known as a component of an image forming device such as a copying machine or a printer. The belt conveying device includes an endless belt such as an intermediate transfer belt that performs primary transfer of toner images of different colors formed on a plurality of photosensitive drums in a sequentially overlapping manner and then performs secondary transfer of the toner images onto a sheet of paper, or a conveying belt that attracts and conveys the sheet of paper.

[0003] In belt conveying devices, there is a problem in that the belt shifts in the axial direction of the rollers that rotatably support the belt, causing the belt to meander. To address this problem, a technology has been proposed that stops the belt from meandering by adjusting the alignment of the rollers.

[0004] For example, the conventional belt device disclosed in Patent Document 1 has a correction mechanism installed for one of the roller members that support the intermediate transfer belt. The correction mechanism tilts the roller member with respect to the rotation axis in conjunction with the movement of the intermediate transfer belt toward the belt, thereby correcting the belt shift of the intermediate transfer belt. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-70694 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned conventional technology, in order to correct the meandering of the belt, it was necessary to constantly maintain a contact state between the shaft tilting member (guided portion) supporting the roller shaft and its abutting member (guiding portion). For this reason, there was concern that these members would be easily worn out due to friction between the shaft tilting member and the abutting member. For example, there was a problem in that the conventional technology did not take into consideration the replacement of worn components. As a result, there was a risk that the performance of stopping the meandering of the belt could not be maintained.

[0007] The present invention has been made in consideration of the above points, and aims to provide a belt conveying device and an image forming apparatus that allow easy replacement of components and can optimally maintain the performance of stopping the belt from meandering. [Means for solving the problem]

[0008] In order to solve the above problems, the belt conveying device of the present invention includes an endless belt, a plurality of rollers, and a correction mechanism. The plurality of rollers rotatably support the belt. The correction mechanism corrects the meandering of the belt relative to the rollers. The correction mechanism includes a pair of inclined bearings and a pair of main body guides. The pair of inclined bearings has a pair of bearing parts that receive the shaft parts of the rollers, and a pair of inclined parts that are inclined symmetrically with respect to the axial direction of the rollers, and rotatably supports the shaft parts of any of the plurality of rollers and is movable in the axial direction. The pair of main body guides contact the pair of inclined parts, and move the end of the axial direction of the roller in a direction perpendicular to the axial direction together with the pair of inclined bearings that move in the axial direction as the belt meanders. The pair of inclined bearings are detachable from the shaft parts of the rollers. Effect of the Invention

[0009] According to the configuration of the present invention, if the pair of inclined bearings are detachable from the shaft portion of the roller, they can be easily replaced. That is, for example, when the pair of inclined portions are worn out, the pair of inclined bearings can be easily replaced. Therefore, it is possible to preferably maintain the performance of stopping the meandering of the belt. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic sectional front view of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] 2 is a schematic cross-sectional front view of the belt conveying device and its periphery of the image forming apparatus in FIG. 1. [Diagram 3] FIG. 3 is a perspective view of the belt conveying device of FIG. 2. [Figure 4] 4 is a perspective view of the belt conveying device of FIG. 3, showing a state in which the belt conveying device is removed from an intermediate frame. FIG. [Diagram 5] 4 is a perspective view of the belt transport device of FIG. 3 with the intermediate transfer belt removed. FIG. [Figure 6] FIG. 6 is an exploded perspective view of a portion around the tension roller in FIG. 5. [Figure 7] FIG. 6 is a partial perspective view of the periphery of a tension roller in FIG. 5. [Figure 8] FIG. 4 is a partial front view of the periphery of the tension roller in FIG. 3. [Figure 9] 4 is a cross-sectional side view of the belt conveying device of FIG. 3. [Figure 10] 10 is an enlarged cross-sectional side view of the belt conveying device of FIG. 9. [Figure 11] 4 is a perspective view of an inclined bearing and a connecting member of the correction mechanism of FIG. 3. [Figure 12] 4 is an exploded partial perspective view of the periphery of a main body guide of the correction mechanism of FIG. 3. [Figure 13] 10 is an enlarged cross-sectional side view of the belt transport device of FIG. 9, illustrating a state in which the intermediate transfer belt meanders. FIG. [Figure 14] 13 is a perspective view of an inclined bearing and a main body guide of the belt conveying device of the first modified example. FIG. [Figure 15]FIG. 15 is a perspective view of the tilt bearing of FIG. [Figure 16] 11 is a perspective view of an inclined bearing and a main body guide of a belt conveying device of a modified example 2. FIG. [Figure 17] FIG. 17 is an exploded perspective view of the tilt bearing and body guide of FIG. 16. [Figure 18] FIG. 4 is a partial cross-sectional front view of the tension roller periphery of FIG. 3. [Figure 19] FIG. 4 is a partial perspective view of the periphery of the tension roller in FIG. 3, showing a state in which the tension arm has been removed. [Figure 20] 4 is a partial perspective view of the periphery of the tension roller in FIG. 3, showing a state in which an inclined bearing and a connecting member of the correction mechanism have been removed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following.

[0012] Fig. 1 is a schematic sectional front view of an image forming apparatus 1 according to an embodiment. Fig. 2 is a schematic sectional front view of a belt conveying device and the periphery of the image forming apparatus 1 according to the embodiment. One example of the image forming apparatus 1 according to the embodiment is a tandem color printer that receives image data and a print command related to a print job from an external computer and transfers a toner image onto paper S using an intermediate transfer belt 41. The image forming apparatus 1 may be a so-called multifunction machine equipped with functions such as printing, scanning (image reading), and facsimile transmission.

[0013] As shown in Figures 1 and 2, the image forming apparatus 1 includes a paper supply unit 3, a paper transport unit 4, an exposure unit 5, an image forming unit 20, a transfer unit 30, a fixing unit 6, a paper discharge unit 7, and a control unit 8, which are provided in a main body 2.

[0014] The paper supply unit 3 is disposed at the bottom of the main body 2. The paper supply unit 3 stores multiple sheets of paper (recording medium) S before printing, and separates and sends out the sheets S one by one when printing. The paper transport unit 4 extends in the vertical direction along the side wall of the main body 2. The paper transport unit 4 transports the paper S sent out from the paper supply unit 3 to the secondary transfer unit 33 and the fixing unit 6, and further ejects the paper S after fixing from the paper ejection port 4a to the paper ejection unit 7. The exposure unit 5 is disposed at the top of the main body 2. The exposure unit 5 irradiates the image forming unit 20 with laser light controlled based on image data.

[0015] The image forming unit 20 is disposed below the exposure unit 5 and above the intermediate transfer belt 41. The image forming unit 20 includes an image forming unit 20Y for yellow, an image forming unit 20C for cyan, an image forming unit 20M for magenta, and an image forming unit 20B for black. These four image forming units 20 have the same basic configuration. Therefore, in the following description, the identification symbols "Y", "C", "M", and "B" representing each color may be omitted unless there is a particular need to limit it.

[0016] The image forming unit 20 includes a photoconductor drum 21 that is supported so as to be rotatable in a predetermined direction (counterclockwise in FIGS. 1 and 2). The image forming unit 20 further includes a charging unit 22, a developing unit 23, and a drum cleaning unit 24 that are arranged around the photoconductor drum 21 along the direction of rotation of the photoconductor drum 21. Note that a primary transfer unit 32 is arranged between the developing unit 23 and the drum cleaning unit 24.

[0017] The photosensitive drum 21 has a photosensitive layer formed on its outer circumferential surface. The charging section 22 charges the outer circumferential surface of the photosensitive drum 21 to a predetermined surface potential. The exposure section 5 exposes the outer circumferential surface of the photosensitive drum 21 charged by the charging section 22, and forms an electrostatic latent image of the document image, the charge of which has been attenuated, on the outer circumferential surface of the photosensitive drum 21. The developing section 23 supplies toner to the electrostatic latent image on the outer circumferential surface of the photosensitive drum 21 to develop it and form a toner image. Each of the four image forming sections 20 forms a toner image of a different color. The drum cleaning section 24 removes and collects any adhering matter, such as toner, remaining on the outer circumferential surface of the photosensitive drum 21 after the toner image is primarily transferred to the outer circumferential surface of the intermediate transfer belt 41. In this manner, the image forming section 20 forms an image (toner image) to be transferred to the paper S later.

[0018] The transfer unit 30 includes a belt conveying device 40, primary transfer units 32Y, 32C, 32M, and 32B, a secondary transfer unit 33, and a belt cleaning unit 34. The belt conveying device 40 is disposed below the four image forming units 20 and above the paper supply unit 3.

[0019] The belt conveying device 40 includes an intermediate transfer belt 41 supported so as to be rotatable in a predetermined direction (counterclockwise in Figs. 1 and 2). The intermediate transfer belt 41 is an endless intermediate transfer body onto which toner images formed on the outer circumferential surfaces of the photoconductor drums 21 in the four image forming units 20 are sequentially superimposed and primarily transferred. The four image forming units 20 are arranged in a line from the upstream side to the downstream side in the rotation direction of the intermediate transfer belt 41 in a so-called tandem system.

[0020] The primary transfer units 32Y, 32C, 32M, and 32B are disposed below the image forming units 20Y, 20C, 20M, and 20B of the respective colors, with the intermediate transfer belt 41 sandwiched therebetween. The secondary transfer unit 33 is disposed upstream of the fixing unit 6 in the paper conveying direction of the paper conveying unit 4, and downstream of the four image forming units 20Y, 20C, 20M, and 20B in the rotation direction of the intermediate transfer belt 41. The belt cleaning unit 34 is disposed downstream of the secondary transfer unit 33 in the rotation direction of the intermediate transfer belt 41.

[0021] The primary transfer unit 32 transfers the toner image formed on the outer peripheral surface of the photoconductor drum 21 onto the outer peripheral surface of the intermediate transfer belt 41. In other words, the toner image is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 41 at the primary transfer units 32Y, 32C, 32M, and 32B of each color. Then, the toner images of the four image forming units 20 are successively superimposed and transferred onto the intermediate transfer belt 41 at a predetermined timing as the intermediate transfer belt 41 rotates, so that a color toner image is formed on the outer peripheral surface of the intermediate transfer belt 41 in which the toner images of four colors, yellow, cyan, magenta, and black, are superimposed.

[0022] The color toner image on the outer peripheral surface of the intermediate transfer belt 41 is transferred to the paper S, which is synchronously fed by the paper transport unit 4, at a secondary transfer nip portion formed in the secondary transfer unit 33. The belt cleaning unit 34 removes and cleans the toner and other deposits remaining on the outer peripheral surface of the intermediate transfer belt 41 after the secondary transfer. In this way, the transfer unit 30 transfers (records) the toner image formed on the outer peripheral surface of the photoconductor drum 21 onto the paper S.

[0023] The fixing unit 6 is disposed above the secondary transfer unit 33. The fixing unit 6 fixes the toner image to the paper S by applying heat and pressure to the paper S onto which the toner image has been transferred.

[0024] The paper discharge section 7 is disposed above the transfer section 30. The paper S on which the toner image has been fixed and printing has been completed is transported to the paper discharge section 7. The paper discharge section 7 takes out the printed paper (printed matter) from the upper side.

[0025] The control unit 8 includes a CPU, an image processing unit, a storage unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operation of each component provided in the image forming apparatus 1 based on control programs and data stored in the storage unit to perform processing related to the functions of the image forming apparatus 1. The paper supply unit 3, the paper transport unit 4, the exposure unit 5, the image forming unit 20, the transfer unit 30, and the fixing unit 6 each receive individual commands from the control unit 8 and work together to print on the paper S. The storage unit is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) or a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

[0026] Next, the configuration of the belt conveying device 40 will be described with reference to FIG. 2, as well as FIG. 3 to FIG. 9. FIG. 3 is a perspective view of the belt conveying device 40 of FIG. 2. FIG. 4 is an exploded perspective view of the belt conveying device 40 of FIG. 3, showing a state in which the belt conveying device 40 is removed from the intermediate frame 2f. FIG. 5 is a perspective view of the belt conveying device 40 of FIG. 3, showing a state in which the intermediate transfer belt 41 is removed. FIGS. 6, 7, and 8 are an exploded partial perspective view, a partial perspective view, and a partial front view of the periphery of the tension roller 43 of the belt conveying device 40 of FIG. 5. FIG. 9 is a cross-sectional side view of the belt conveying device 40 of FIG. 3. Note that the axial direction Dx of the tension roller 43 is indicated by an arrow in FIG. 3 and subsequent figures. Also, in FIG. 6, each component is drawn exploded toward the side of the belt conveying device 40.

[0027] The belt conveying device 40 is disposed along and below the four image forming units 20Y, 20C, 20M, and 20B, as shown in Fig. 2. The belt conveying device 40 is also disposed above a plate-shaped intermediate frame 2f that is provided on the main body 2 and extends in a substantially horizontal direction, as shown in Figs. 2, 3, and 4.

[0028] The belt conveying device 40 is formed in a substantially rectangular parallelepiped shape extending substantially horizontally. Four hooks 40h are provided on the bottom of the belt conveying device 40. The intermediate frame 2f has four holes 2h that penetrate the intermediate frame 2f in the vertical direction and face the four hooks 40h of the belt conveying device 40. The hooks 40h are inserted into the holes 2h and hooked, so that the belt conveying device 40 is detachably attached to the intermediate frame 2f.

[0029] The belt conveying device 40 includes an intermediate transfer belt 41, a drive roller 42, a tension roller 43, a pair of tension arms 44, and a pair of tension springs (urging members) 45.

[0030] The intermediate transfer belt 41 is an endless belt rotatably mounted on a plurality of rollers. In this embodiment, the plurality of rollers includes a drive roller 42 and a tension roller 43. The rotation axes of the drive roller 42 and the tension roller 43 are parallel to the rotation axis of the photoconductor drum 21 and extend in the depth direction of the paper in FIG. 2.

[0031] A primary transfer roller 32r is disposed below each of the four image forming units 20Y, 20C, 20M, and 20B of the belt conveying device 40, with the intermediate transfer belt 41 between them. Each of the four primary transfer rollers 32r is disposed at a position facing the photoconductor drum 21 with the intermediate transfer belt 41 therebetween, and contacts the inner circumferential surface of the intermediate transfer belt 41. The drive roller 42, the tension roller 43, and each of the four primary transfer rollers 32r are rotatably supported by a side plate 461 of a housing 46 of the belt conveying device 40. In more detail, the tension roller 43 is held by a pair of tension arms 44 supported by the side plate 461 so as to be swingable.

[0032] The drive roller 42 is disposed upstream of the four image forming units 20Y, 20C, 20M, and 20B with respect to the rotation direction of the intermediate transfer belt 41. The drive roller 42 receives power from a drive motor (not shown) via a drive gear 42g attached on the same shaft, and rotates the intermediate transfer belt 41 in the clockwise direction in FIG.

[0033] The drive roller 42 is disposed adjacent to the secondary transfer unit 33. A secondary transfer roller 33r is disposed in the secondary transfer unit 33. The secondary transfer roller 33r is disposed at a position facing the drive roller 42 with the intermediate transfer belt 41 therebetween, and is in contact with the outer circumferential surface of the intermediate transfer belt 41.

[0034] The tension roller 43 is disposed downstream of the four image forming units 20Y, 20C, 20M, and 20B in the rotation direction of the intermediate transfer belt 41. The tension roller 43 rotates clockwise in FIG. 2 in accordance with the rotation of the intermediate transfer belt 41. A pair of bearing members 431 are disposed on both ends of the tension roller 43 in the axial direction Dx (the depth direction of the paper in FIG. 2). Both ends of the shaft portion 43x of the tension roller 43 in the axial direction Dx are inserted into the pair of bearing members 431, respectively.

[0035] The tension roller 43 is held by a pair of tension arms 44 that are swingably supported on a side plate 461 of the housing 46 via bearing members 431. The tension roller 43 is biased by a pair of tension springs 45 in a direction away from the drive roller 42. In other words, the tension roller 43 is biased by the pair of tension springs 45 in a direction that increases the tension of the intermediate transfer belt 41. As a result, a predetermined tension is applied to the intermediate transfer belt 41.

[0036] Each of the pair of tension arms 44 is disposed at both ends in the axial direction Dx of the tension roller 43. Each of the pair of tension arms 44 extends in a direction in which the drive roller 42 and the tension roller 43 approach and move away from each other.

[0037] A pair of arm support portions 462 are formed on the side plate 461 of the housing 46. The pair of arm support portions 462 are formed in a shaft shape extending along the axial direction Dx of the tension roller 43.

[0038] Each of the pair of tension arms 44 has a hole 441 that is disposed in a direction approaching the drive roller 42 with respect to the tension roller 43 and penetrates in the axial direction Dx of the tension roller 43. The pair of arm support parts 462 of the housing 46 are inserted into the hole parts 441 of the tension roller 43, so that the pair of tension arms 44 are supported by the housing 46 to be swingable around the axes of the pair of arm support parts 462.

[0039] Each of the pair of tension arms 44 has a housing portion 442. The housing portion 442 is disposed in a direction away from the drive roller 42 with respect to the hole portion 441. The housing portion 442 extends in a direction away from the hole portion 441, i.e., the arm support portion 462 of the housing 46, and perpendicular to the axial direction Dx of the tension roller 43.

[0040] The accommodation portion 442 accommodates the bearing member 431 and tension spring 45 of the tension roller 43. In the accommodation portion 442, the tension spring 45 and the bearing member 431 are arranged in this order with respect to the hole portion 441 (arm support portion 462). The bearing member 431 is movable in the accommodation portion 442 in the extension direction of the accommodation portion 442, that is, in the direction approaching or moving away from the hole portion 441.

[0041] The pair of tension springs (biasing members) 45 are housed in the respective housing portions 442 of the pair of tension arms 44. The pair of tension springs 45 are constituted, for example, by compression coil springs, and are disposed between the hole portions 441 of the pair of tension arms 44 and the bearing members 431 of the tension roller 43. The pair of tension springs 45 bias the tension roller 43 (specifically, the bearing members 431) in a direction away from the arm support portion 462. In other words, the pair of tension springs 45 bias the tension roller 43 in a direction that increases the tension of the intermediate transfer belt 41.

[0042] Next, the configuration of the periphery of the tension roller 43 of the belt conveying device 40 will be described with reference to Figs. 10 to 13. Fig. 10 is an enlarged cross-sectional side view of the belt conveying device 40 of Fig. 9. Fig. 11 is a perspective view of the inclined bearing and the connecting member of the correction mechanism 50 of the belt conveying device 40 of Fig. 3. Fig. 12 is an exploded partial perspective view of the periphery of the main body guide of the correction mechanism 50 of Fig. 3. Fig. 13 is an enlarged cross-sectional side view of the belt conveying device 40 of Fig. 9, showing a state in which the intermediate transfer belt 41 is meandering. Note that Figs. 10 and 13 omit the drawing of the central part of the tension roller 43 in the axial direction Dx. Also, in Fig. 12, each component is drawn exploded upward.

[0043] 10. The correction mechanisms 50 are disposed at both ends of the tension roller 43 in the axial direction Dx and below the tension roller 43. The correction mechanisms 50 correct meandering of the intermediate transfer belt 41 relative to the tension roller 43. The correction mechanism 50 includes a pair of inclined bearings 52, a connecting member 53, and a pair of main body guides 54.

[0044] The pair of inclined bearings 52 are disposed at both ends of the tension roller 43 in the axial direction Dx. Each of the pair of inclined bearings 52 is located more inward than the bearing member 431 of the tension roller 43 in the axial direction Dx. Also, each of the pair of inclined bearings 52 is located more outward than the intermediate transfer belt 41 in the axial direction Dx. The pair of inclined bearings 52 are attached to and support the shaft portion 43x of the tension roller 43 so as to be rotatable about the axis. The pair of inclined bearings 52 are movable in the axial direction Dx of the tension roller 43.

[0045] The connecting member 53 is disposed to the side of the tension roller 43, radially outward of the tension roller 43, and spaced apart from the tension roller 43. The connecting member 53 is a plate-shaped member extending in the up-down direction and along the axial direction Dx of the tension roller 43. The connecting member 53 connects to each of the pair of inclined bearings 52 at both ends of the tension roller 43 in the axial direction Dx. In other words, the connecting member 53 connects the pair of inclined bearings 52. As a result, the pair of inclined bearings 52 move in the same direction and at the same timing in the axial direction Dx of the tension roller 43.

[0046] The pair of inclined bearings 52 each includes a pair of bearing portions 521 and a pair of inclined portions 522 .

[0047] The pair of bearing portions 521 are located outside the roller portion of the tension roller 43 and inside the bearing member 431 in the axial direction Dx of the tension roller 43. The pair of bearing portions 521 are also located outside the intermediate transfer belt 41 in the axial direction Dx. The shaft portion 43x of the tension roller 43 penetrates the pair of bearing portions 521 in the axial direction Dx. The pair of bearing portions 521 receive the shaft portion 43x of the tension roller 43.

[0048] The pair of bearings 521 are formed in a plate shape extending in a direction perpendicular to the axial direction Dx of the tension roller 43 (the radial direction of the tension roller 43). The inner surfaces of the pair of bearings 521 in the axial direction Dx face both ends of the intermediate transfer belt 41 in the axial direction Dx in the axial direction Dx. When the intermediate transfer belt 41 meanders, the side edges of the intermediate transfer belt 41 in the axial direction Dx come into contact with the inner surfaces of the pair of bearings 521 in the axial direction Dx.

[0049] The pair of inclined portions 522 are disposed below the pair of inclined bearings 52, respectively. The pair of inclined portions 522 are connected to the lower ends of the pair of bearing portions 521, respectively. When viewed from a direction perpendicular to the axial direction Dx of the tension roller 43 (e.g., from the side), the pair of inclined portions 522 are disposed inside the pair of bearing portions 521 in the axial direction Dx. Furthermore, when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43, the pair of inclined portions 522 are located below the tension roller 43. Each of the pair of inclined portions 522 faces and comes into contact with each of the pair of main body guides 54, respectively.

[0050] Each of the pair of inclined portions 522 has an inclined surface 522s. The inclined surfaces 522s of the pair of inclined portions 522 are flat and inclined with respect to the axial direction Dx of the tension roller 43. In detail, the inclined surface 522s is configured as a flat surface that is inclined from the radial center side of the tension roller 43 to the outside (from the top to the bottom in FIG. 10) as it moves from the inside to the outside in the axial direction Dx of the tension roller 43 (from the center to both left and right outer sides in FIG. 10). The inclinations of the pair of inclined portions 522 are symmetrical with each other with respect to the center of the axial direction Dx of the tension roller 43.

[0051] The pair of main body guides 54 are disposed at positions facing the pair of inclined portions 522 in the up-down direction, and are fixed to the intermediate frame 2f of the main body 2. The pair of main body guides 54 are disposed on the inside in the axial direction Dx of the pair of bearing portions 521 when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43 (e.g., from the side).

[0052] 10 and 12, the intermediate frame 2f includes a pair of pedestal portions 2b. The pair of pedestal portions 2b are disposed at positions facing the pair of inclined portions 522 of the intermediate frame 2f in the up-down direction. Each of the pair of pedestal portions 2b supports a pair of main body guides 54, respectively.

[0053] Furthermore, the pair of main body guides 54 are formed, for example, by a pair of cylindrical members, and extend in a direction perpendicular to the axial direction Dx of the tension roller 43 (the depth direction of the paper in FIG. 10). In other words, the pair of main body guides 54 extend in a direction in which the drive roller 42 and the tension roller 43 approach and move away from each other. Each of the pair of main body guides 54 faces and comes into contact with the respective inclined surfaces 522s of the pair of inclined portions 522.

[0054] 13, when the intermediate transfer belt 41 meanders, the intermediate transfer belt 41 comes into contact with one of the pair of inclined bearings 52 and pushes the inclined bearing 52 toward the outside in the axial direction Dx (the right side in FIG. 13). The inclined bearing 52 moves toward the outside in the axial direction Dx.

[0055] As a result, one end side (right side in FIG. 13) of the tension roller 43 in the axial direction Dx moves downward as the inclined bearings 52 slide on the main body guide 54 via the inclined surfaces 522s of the inclined portions 522. In other words, the main body guide 54 moves the one end side of the tension roller 43 in the axial direction Dx in a direction perpendicular to the axial direction Dx (up and down direction) together with the pair of inclined bearings 52 that move in the axial direction Dx of the tension roller 43 as the intermediate transfer belt 41 meanders.

[0056] The entire tension roller 43 is tilted, thereby stopping the meandering of the intermediate transfer belt 41. As a result, the intermediate transfer belt 41 continues to rotate stably.

[0057] At the location of the tension roller 43, tension is applied to the intermediate transfer belt 41, which makes it easier for the intermediate transfer belt 41 to meander. Therefore, by providing a correction mechanism 50, which is an alignment adjustment mechanism, for the tension roller 43, it is possible to improve the performance of stopping the meandering of the intermediate transfer belt 41.

[0058] As described above, the pair of inclined portions 522 and the pair of main body guides 54 are disposed on the inside of the pair of bearing portions 521 in the axial direction Dx when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43. With this configuration, the pair of inclined portions 522 and the pair of main body guides 54 of the correction mechanism 50 that inclines the tension roller 43 are not positioned outside both ends of the tension roller 43 in the axial direction Dx. That is, the belt conveying device 40 can be made smaller in size in the axial direction Dx of the tension roller 43. Therefore, the belt conveying device 40 can stop the meandering of the intermediate transfer belt 41 with a configuration that has been made smaller in size.

[0059] More specifically, as shown in FIG. 10, the pair of inclined portions 522 and the pair of main body guides 54 are positioned inside both ends of the intermediate transfer belt 41 in the axial direction Dx when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43.

[0060] According to the above configuration, the pair of inclined portions 522 and the pair of main body guides 54 are disposed closer to the center in the axial direction Dx of the tension roller 43 than the pair of bearing portions 521 with which the intermediate transfer belt 41 comes into contact as the intermediate transfer belt 41 meanders. This makes it possible to increase the amount of movement of one end side of the axial direction Dx of the tension roller 43 in a direction perpendicular to the axial direction Dx (up and down direction) relative to the amount of movement of the inclined bearings 52 outward in the axial direction Dx. Therefore, the belt conveying device 40 can more effectively stop the meandering of the intermediate transfer belt 41 with a compact configuration.

[0061] As described above, the pair of inclined portions 522 and the pair of main body guides 54 are disposed below the tension roller 43 supported by the pair of inclined bearings 52. The pair of main body guides 54 are disposed below the pair of inclined portions 522. Gravity acts on the tension roller 43, causing the pair of inclined bearings 52 to be pressed against the pair of main body guides 54. When the intermediate transfer belt 41 is rotating normally and not meandering, the shaft portion 43x of the tension roller 43 is approximately horizontal. While the intermediate transfer belt 41 is rotating normally, the state shown in FIG. 10 is maintained.

[0062] According to the above configuration, the action of gravity on the tension roller 43 can be utilized to easily bring the pair of inclined portions 522 and the pair of main body guides 54 into contact with each other and maintain the contact. This eliminates the need for a biasing member that generates a biasing force for bringing the pair of inclined portions 522 and the pair of main body guides 54 closer to each other and into contact with each other. This allows the correction mechanism 50 to have a simple configuration, and further enables the belt conveying device 40 to be made more compact.

[0063] 8, the tension roller 43 rotates in the direction in which the portion of the intermediate transfer belt 41 in contact with the tension roller 43 moves from the top to the bottom in accordance with the rotation of the intermediate transfer belt 41. That is, in FIG. 8, the tension roller 43 rotates clockwise. In addition, in terms of the periphery of the tension roller 43, the pair of inclined portions 522 and the pair of main body guides 54 are disposed downstream of the portion in contact with the tension roller 43 supported by the pair of inclined bearings 52 in the moving direction of the intermediate transfer belt 41.

[0064] According to the above configuration, a torque is generated around the axis of the tension roller 43 by the movement of the portion of the intermediate transfer belt 41 that contacts the tension roller 43. The torque is generated toward the downstream side with respect to the direction of movement of the portion of the intermediate transfer belt 41 that contacts the tension roller 43. In other words, the force generated around the axis of the tension roller 43 by the movement of the intermediate transfer belt 41 acts in a direction that presses the pair of inclined portions 522 toward the pair of main body guides 54. This eliminates the need for a biasing member that generates a biasing force for bringing the pair of inclined portions 522 and the pair of main body guides 54 closer to each other and into contact with each other.

[0065] 8, a pair of arm support parts 462 that support a pair of tension arms 44 for increasing the tension of the intermediate transfer belt 41 are disposed above the shaft part 43x of the tension roller 43. That is, the pair of tension springs 45 urge the tension roller 43 in a direction away from the arm support parts 462, thereby applying the urging force downward to the arm support parts 462.

[0066] According to the above configuration, the biasing force of the pair of tension springs 45 on the tension roller 43 acts in a direction pressing the pair of inclined portions 522 toward the pair of main body guides 54. This eliminates the need for a biasing member that generates a biasing force for bringing the pair of inclined portions 522 and the pair of main body guides 54 closer to each other and into contact with each other. This allows the correction mechanism 50 to have a simple configuration, and further enables the belt conveying device 40 to be made more compact.

[0067] The tension arm 44 has a housing portion 442 that houses the bearing member 431 of the tension roller 43 and the tension spring 45. With this configuration, the tension spring 45 can bias the tension roller 43 in a predetermined direction along the extension direction of the housing portion 442. This makes it possible to effectively increase the tension of the intermediate transfer belt 41. Therefore, the transfer performance can be improved in the primary transfer and secondary transfer of the toner image.

[0068] As described above, each of the pair of inclined portions 522 has an inclined surface 522s, and each of the pair of main body guides 54 is formed of a cylindrical member. In other words, the pair of main body guides 54 are formed of curved surfaces whose contact areas with the pair of inclined portions 522 are convex toward the pair of inclined portions 522 when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43 (sideways).

[0069] Fig. 14 is a perspective view of the inclined bearing 52 and the main body guide 54 of the belt conveying device 40 of the modified example 1. Fig. 15 is a perspective view of the inclined bearing 52 of Fig. 14. As shown in Figs. 14 and 15 as the modified example 1, each of the pair of inclined portions 522 has a curved surface 522c.

[0070] The ridgeline of the curved surface 522c, as viewed from a direction (side) perpendicular to the axial direction Dx of the tension roller 43, is configured as a straight line that inclines from the radial center side of the tension roller 43 to the outside (from top to bottom in FIGS. 14 and 15) as it moves from the inside (center) to the outside in the axial direction Dx of the tension roller 43. The pair of inclined portions 522 are configured as curved surfaces 522c whose contact areas with the pair of main body guides 54 are convex toward the pair of main body guides 54, as viewed from a direction (side) perpendicular to the axial direction Dx of the tension roller 43.

[0071] In this way, the contact area of ​​one of the pair of inclined portions 522 and the pair of main body guides 54 with the other is configured as a curved surface that is convex toward the other that contacts the other when viewed from a direction perpendicular to the axial direction Dx of the tension roller 43. With this configuration, it is possible to reduce the contact area between the pair of inclined portions 522 and the pair of main body guides 54. In other words, it is possible to reduce the frictional force generated between the pair of inclined portions 522 and the pair of main body guides 54. Therefore, it is possible to suppress wear of the pair of inclined portions 522 and the pair of main body guides 54, and it is possible to preferably maintain the performance of stopping the meandering of the intermediate transfer belt 41.

[0072] Moreover, by configuring the pair of main body guides 54 in a cylindrical shape, it is possible to easily form the pair of main body guides 54 that reduce the contact area with the pair of inclined portions 522. Therefore, the correction mechanism 50 can be simply configured, and the belt conveying device 40 can be made more compact.

[0073] The contact areas of the pair of inclined portions 522 with the pair of main body guides 54 may be cylindrical. Also, the contact areas of the pair of main body guides 54 with the pair of inclined portions 522 may be configured as inclined portions having curved surfaces.

[0074] Furthermore, the pair of main body guides 54 formed of cylindrical members may be rotating bodies that rotate about an axis extending in a direction perpendicular to the axial direction Dx of the tension roller 43.

[0075] Fig. 16 is a perspective view of the inclined bearing 52 and the main body guide 55 of the belt conveyor 40 of the modified example 2. Fig. 17 is an exploded perspective view of the periphery of the main body guide 55 of Fig. 16. Note that Fig. 17 depicts the main body guide 55 and the base portion 2b exploded upward. As shown in Figs. 16 and 17 as modified example 2, each of the pair of main body guides 55 is formed of a sphere.

[0076] Each of the pair of body guides 55 formed of a sphere is a rotating body that rotates with respect to the pair of base portions 2b about an axis extending in a direction perpendicular to at least the axial direction Dx of the tension roller 43. Each of the pair of body guides 55 faces and comes into contact with each of the inclined surfaces 522s of the pair of inclined portions 522.

[0077] A rotor that rotates about an axis extending in a direction perpendicular to the axial direction Dx may be configured in the contact area between the pair of inclined portions 522 and the pair of main body guides. In this manner, the contact area between the pair of inclined portions 522 and one of the pair of main body guides 54, 55 and the other is configured as a rotor that rotates about an axis extending in a direction perpendicular to the axial direction Dx of the tension roller 43.

[0078] According to the above configuration, the contact area between the pair of inclined portions 522 and the pair of main body guides 54, 55 can be made to have rolling friction. Since the frictional force of rolling friction is much smaller than that of sliding friction, it is possible to reduce the frictional load. By reducing the frictional load, it is possible to suppress wear of the pair of inclined portions 522 and the pair of main body guides 54, 55, and it is possible to preferably maintain the performance of stopping the meandering of the intermediate transfer belt 41.

[0079] Fig. 18 is a partial cross-sectional front view of the periphery of tension roller 43 in Fig. 3. Fig. 19 is a partial perspective view of the periphery of tension roller 43 in Fig. 3, showing a state in which tension arm 44 has been removed. Fig. 20 is a partial perspective view of the periphery of tension roller 43 in Fig. 3, showing a state in which inclined bearing 52 and connecting member 53 of correction mechanism 50 have been removed.

[0080] Each of the pair of inclined bearings 52 further includes a through portion 523 and a groove portion 524. The through portion 523 and the groove portion 524 are formed in each of the pair of bearing portions 521.

[0081] The through portion 523 is disposed at a position facing the shaft portion 43x of the tension roller 43 when viewed from the axial direction Dx of the tension roller 43. The through portion 523 is formed as a hole portion that penetrates the bearing portion 521 in the axial direction Dx. The shaft portion 43x of the tension roller 43 is inserted into the through portion 523.

[0082] The groove 524 extends from the through-hole 523 in a direction perpendicular to the axial direction Dx. More specifically, the groove 524 extends from the through-hole 523 toward the arm support portion 462 side of the housing 46 (the drive roller 42 side with respect to the tension roller 43) and upward. The groove 524 opens at an edge of the bearing portion 521.

[0083] According to the configuration of the through-hole 523 and the groove 524, the shaft 43x of the tension roller 43 can be inserted and removed through the groove 524 between the outside of the bearing part 521 and the through-hole 523. That is, the pair of inclined bearings 52 are detachable from the shaft 43x of the tension roller 43, as shown in FIG.

[0084] If the pair of inclined bearings 52 are detachable from the shaft portion 43x of the tension roller 43, the pair of inclined bearings 52 can be easily replaced. That is, for example, when the pair of inclined portions 522 are worn out, the pair of inclined bearings 52 can be easily replaced. Therefore, it is possible to preferably maintain the performance of stopping the meandering of the intermediate transfer belt 41.

[0085] The pair of inclined bearings 52 are connected by a connecting member 53, and can be attached and detached as a unit to the shaft portion 43x of the tension roller 43. That is, the pair of inclined bearings 52 arranged at both ends of the tension roller 43 in the axial direction Dx can be attached and detached to the shaft portion 43x at the same time. This improves the ease of replacement of the pair of inclined bearings 52.

[0086] The connecting member 53 further includes a density sensor 56. The density sensor 56 is attached to a side surface of the connecting member 53, which is a plate-shaped member extending along the axial direction Dx. The density sensor 56 is disposed to face the outer circumferential surface of the intermediate transfer belt 41.

[0087] The density sensor 56 is composed of a reflective optical sensor having a light-emitting section including a light-emitting element such as an LED (Light Emitting Diode) and a light-receiving section including a light-receiving element such as a photodiode. The light-emitting section irradiates detection light at a predetermined angle toward the toner image primarily transferred onto the outer circumferential surface of the intermediate transfer belt 41. The light-receiving section receives the detection light that is irradiated by the light-emitting section toward the toner image and reflected by the toner image.

[0088] The concentration sensor 56 outputs the level of the detection light received by the light receiving section as a detection value (voltage value) related to the toner concentration, thereby deriving the toner amount of the toner image primarily transferred onto the outer peripheral surface of the intermediate transfer belt 41, and can detect the toner concentration of the toner image. For example, when there is no toner on the outer peripheral surface of the intermediate transfer belt 41, the detection light irradiated from the light emitting section is specularly reflected without being diffusely reflected by the toner, and is incident on the light receiving section in large amounts. This increases the detection value (voltage value) related to the toner concentration. And, as the amount of toner on the outer peripheral surface of the intermediate transfer belt 41 increases, more light is diffusely reflected by the toner, and the amount of light incident on the light receiving section gradually decreases. This gradually decreases the detection value (voltage value) related to the toner concentration.

[0089] According to the above configuration, the concentration sensor 56 tilts following the overall tilt of the tension roller 43 caused by the correction mechanism 50. That is, even if the intermediate transfer belt 41 meanders and the entire tension roller 43 tilts, the relative position of the concentration sensor 56 with respect to the outer circumferential surface of the intermediate transfer belt 41 does not change. Therefore, the detection accuracy of the toner concentration by the concentration sensor 56 can be stabilized and further preferably maintained. In addition, since the connecting member 53 is detachable from the shaft portion 43x of the tension roller 43, the concentration sensor 56 can be easily replaced, for example, when a malfunction occurs.

[0090] Although an embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

[0091] For example, in the above embodiment, the belt conveying device 40 is configured to include the intermediate transfer belt 41 onto which the toner images formed by the four image forming units 20 are transferred in a superimposed manner, but the present invention is not limited to such a device. The present invention is also applicable to a belt conveying device including a conveying belt that conveys a recording medium on which an image is recorded by the image forming unit, for example. This makes it possible for the belt conveying device to stop meandering of the conveying belt that conveys the recording medium with a compact configuration.

[0092] In the above embodiment, the image forming apparatus 1 is a so-called tandem type image forming apparatus for color printing, but is not limited to this type of apparatus. The image forming apparatus may be a type of image forming apparatus for color printing other than the tandem type, as long as it is equipped with an intermediate transfer belt. [Industrial Applicability]

[0093] The present invention can be used in a belt conveying device and an image forming apparatus. [Explanation of symbols]

[0094] 1. Image forming device 2 Main unit 2b Pedestal 2f Intermediate frame 20 Image forming section 21 Photoconductor drum 30 Transcription section 40 Belt conveyor 41 Intermediate transfer belt (belt) 43 Tension roller 43x shaft 44 Tension Arm 45 Tension spring (biasing member) 46 Case 50 Correction mechanism 52 Inclined bearing 53 Connecting members 54, 55 Main body guide 56 Concentration Sensor 431 Bearing parts 442 Storage unit 461 Side Panel 462 Arm support 521 Bearing section 522 Slope 522c Curved Surface 522s slope 523 Penetration 524 Groove Dx axial direction S Paper (recording medium)

Claims

1. An endless belt; A plurality of rollers on which the belt is rotatably supported; a correction mechanism for correcting meandering of the belt relative to the roller; Equipped with The correction mechanism includes: a pair of inclined bearings each having a pair of bearing portions for receiving the shaft portion of the roller and a pair of inclined portions inclined symmetrically with respect to the axial direction of the roller, the pair of inclined bearings rotatably supporting the shaft portion of any one of the plurality of rollers and movable in the axial direction; A pair of main body guides that contact the pair of inclined portions and move the axial end portions of the rollers in a direction perpendicular to the axial direction together with the pair of inclined bearings that move in the axial direction as the belt meanders; Equipped with A belt conveying device according to claim 1, wherein the pair of inclined bearings are detachable from the shaft portions of the rollers.

2. The inclined bearing is a through-hole into which the shaft portion of the roller is inserted; A groove portion extending from the through portion in a direction perpendicular to the axial direction and opening at an edge of the inclined bearing; 2. The belt conveying device according to claim 1, further comprising:

3. 2. The belt conveying device according to claim 1, wherein the correction mechanism includes a connecting member extending in the axial direction of the roller and connecting each of the pair of inclined bearings.

4. 4. The belt conveying device according to claim 3, wherein the connecting member is provided with a density sensor disposed opposite to the outer circumferential surface of the belt and configured to detect a toner density of a toner image on the outer circumferential surface of the belt.

5. A plurality of image forming units; a belt conveying device according to claim 1 , the belt conveying device being disposed adjacent to the image forming unit and conveying a recording medium on which an image is recorded by the image forming unit; An image forming apparatus comprising:

6. A plurality of image forming units; a belt conveying device according to claim 1, which is disposed adjacent to the image forming unit, and the belt is an intermediate transfer belt onto which toner images formed in the image forming unit are transferred in a superimposed manner; An image forming apparatus comprising:

Images