Belt device and image forming device

Abstract

To make a restricting member that restricts movement of a roller member in width direction inclined by a correction mechanism and the roller member hardly wearable.SOLUTION: An intermediate transfer belt 8 (belt member) stretched and supported to a plurality of roller members, a correction mechanism 79 that inclines a correction roller 17 (one roller member) among the plurality of roller members in conjunction with the operation of the intermediate transfer belt 8 moving in the width direction, and a swinging side plate 75 (holding member) that rotatably holds a shank 17b of the correction roller 17 are provided. Furthermore, a screw member 87 (restricting member) that restricts the movement of the correction roller 17 in the width direction is located on the widthwise outside of the shank 17b to the swinging side plate 75 so as to be indirectly or directly contactable to the swinging side plate 75. Meanwhile, the screw member 87 is fixed to the shank 17b so as to be rotatable together with the correction roller 17.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a belt device having a belt member that travels in a predetermined direction, and an image forming apparatus including the belt device, such as a copying machine, a printer, a facsimile machine, or a combination machine thereof. [Background technology]

[0002] BACKGROUND ART Conventionally, in a belt device in an image forming apparatus, a correction mechanism that corrects belt deviation of a belt member such as an intermediate transfer belt is known (see, for example, Patent Document 1). The correction mechanism tilts one of the multiple roller members that support and stretch the belt member in conjunction with the movement of the belt member in the width direction (toward the belt), thereby moving the belt member in the opposite direction.

[0003] On the other hand, Patent Document 1 discloses a technology in which a regulating member such as an E-ring that regulates the widthwise movement of a roller member tilted by a correction mechanism is installed on the shaft portion of the roller member via an intermediate member, outside the widthwise direction of a support member that rotatably supports the roller member. Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional belt devices, the regulating member does not rotate as the roller member rotates, and the roller member comes into sliding contact with the regulating member, causing at least one of them to wear out, making it difficult to perform the function of correcting the belt member's belt misalignment.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a belt device and an image forming device in which the regulating member that regulates the widthwise movement of the roller member tilted by the correction mechanism and the roller member are less likely to wear out. [Means for solving the problem]

[0006] The belt device of this invention comprises a belt member stretched and supported by a plurality of roller members, a correction mechanism that tilts one of the plurality of roller members in conjunction with the movement of the belt member in the width direction, a holding member that rotatably holds the shaft portion of the one roller member, and a regulating member that is arranged on the shaft portion outside the width direction of the holding member so as to be able to indirectly or directly contact the holding member and regulates the width direction movement of the one roller member, and the regulating member is fixed to the shaft portion so as to be able to rotate integrally with the one roller member. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a belt device and an image forming apparatus in which the roller member and the regulating member that regulates the movement of the roller member in the width direction tilted by the correction mechanism are less likely to wear out. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 2 is an enlarged structural view showing a part of an image forming unit. [Figure 3] FIG. 2 is a schematic diagram showing an intermediate transfer belt device and its vicinity. [Figure 4] FIG. 2 is a cross-sectional view showing one end side in the width direction of the intermediate transfer belt and the correction roller. [Figure 5] FIG. 2 is a diagram illustrating a configuration of a part of an intermediate transfer belt device. [Figure 6] 10A and 10B are cross-sectional views showing an operation of correcting the belt deviation of the intermediate transfer belt. [Figure 7] 10A and 10B are diagrams for explaining a mechanism for correcting belt deviation of an intermediate transfer belt. [Figure 8] FIG. 2 is a top view showing a main part of the intermediate transfer belt device. [Figure 9] FIG. 2 is a cross-sectional view showing the intermediate transfer belt and the correction roller across the entire width direction. [Figure 10]FIG. 10 is a cross-sectional view showing one end side in the width direction of an intermediate transfer belt and a correction roller as a comparative example. [Figure 11] 10 is a cross-sectional view showing one end side in the width direction of an intermediate transfer belt and a correction roller according to a first modified example. FIG. [Figure 12] FIG. 10 is a cross-sectional view showing one end side in the width direction of an intermediate transfer belt and a correction roller according to a second modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus 100 will be described with reference to FIGS. FIG. 1 is a structural diagram showing a printer as an image forming apparatus, and FIG. 2 is an enlarged view showing a part of the image forming unit. 1, an intermediate transfer belt device 15 serving as a belt device is installed in the center of the image forming apparatus main body 100. Furthermore, imaging units 6Y, 6M, 6C, and 6K corresponding to each color (yellow, magenta, cyan, and black) are arranged side by side so as to face the intermediate transfer belt 8 of the intermediate transfer belt device 15. Furthermore, a secondary transfer belt device 69 is installed below the intermediate transfer belt device 15.

[0011] 2, the imaging unit 6Y corresponding to yellow is made up of a photosensitive drum 1Y, a charging unit 4Y arranged around the photosensitive drum 1Y (photosensitive member), a developing unit 5Y, a cleaning unit 2Y, a lubricant supplying device 3, and a discharging unit. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process, discharging process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

[0012] The other three image forming units 6M, 6C, and 6K are configured in a manner similar to that of the image forming unit 6Y corresponding to yellow, except that they use different toner colors, and form images corresponding to their respective toner colors. Below, we will omit the explanation of the other three image forming units 6M, 6C, and 6K as appropriate, and will only explain the image forming unit 6Y corresponding to yellow.

[0013] 2, the photosensitive drum 1Y is rotated counterclockwise by a main motor, and the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (charging step). Thereafter, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser light L emitted from the exposure unit 7, and an electrostatic latent image corresponding to yellow is formed by exposure scanning in the width direction (the direction perpendicular to the paper surface of Figures 1 and 2, which is the main scanning direction) at this position (this is the exposure process).

[0014] Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the developing unit 5Y, where the electrostatic latent image is developed to form a yellow toner image (developing step). Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the intermediate transfer belt 8 and the primary transfer roller 9Y, and at this position the toner image formed on the surface of the photosensitive drum 1Y is primarily transferred onto the surface of the intermediate transfer belt 8 (primary transfer step). At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.

[0015] Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and at this position, the untransferred toner remaining on the photosensitive drum 1Y is collected into the cleaning unit 2Y by the cleaning blade 2a (cleaning process). Here, a lubricant supply device 3 (photosensitive drum lubricant supply device) consisting of a lubricant supply roller 3a, a solid lubricant 3b, a compression spring 3c, etc. is installed inside the cleaning section 2Y. The lubricant supply roller 3a, which rotates clockwise in Fig. 2, scrapes off the lubricant little by little from the solid lubricant 3b, and the lubricant is supplied to the surface of the photosensitive drum 1Y by the lubricant supply roller 3a. Finally, the surface of the photosensitive drum 1Y reaches a position facing the charge removing unit, where the residual potential on the photosensitive drum 1Y is removed. Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

[0016] The above-described image formation process is performed in the other imaging units 6M, 6C, and 6K in the same manner as in the yellow imaging unit 6Y. That is, laser light L based on image information is irradiated from an exposure unit 7 disposed above the imaging units onto the photosensitive drums 1M, 1C, and 1K of the imaging units 6M, 6C, and 6K. More specifically, the exposure unit 7 emits laser light L from a light source, and while scanning the laser light L with a rotationally driven polygon mirror, irradiates the photosensitive drums via multiple optical elements. Note that the exposure unit 7 may be configured with multiple LEDs arranged in the width direction. Thereafter, the toner images of each color formed on the photosensitive drums 1M, 1C, and 1K through the development process by the developing units 5M, 5C, and 5K are primarily transferred onto the intermediate transfer belt 8 in a superimposed manner. In this way, a color image is formed on the intermediate transfer belt 8.

[0017] Here, the intermediate transfer belt 8 as a belt member is stretched and supported by a plurality of roller members 16 to 19, 40, and is moved endlessly in the direction of the arrow in FIG. 3 by the rotational drive of the drive roller 16 by the drive motor Mt1. The four primary transfer rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 between themselves and the photosensitive drums 1Y, 1M, 1C, and 1K, respectively, to form primary transfer nips. A transfer voltage (primary transfer bias) of a polarity opposite to that of the toner is applied to the primary transfer rollers 9Y, 9M, 9C, and 9K. Then, the intermediate transfer belt 8 travels in the direction of the arrow and passes through the primary transfer nips of the primary transfer rollers 9Y, 9M, 9C, and 9K in sequence. In this way, the toner images of each color on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred onto the surface of the intermediate transfer belt 8 in a superimposed manner (this is the primary transfer process).

[0018] Thereafter, the intermediate transfer belt 8 (belt member) onto which the toner images of each color have been primarily transferred in a superimposed state reaches a position facing the secondary transfer belt 72. At this position, the secondary transfer opposing roller 40 sandwiches the intermediate transfer belt 8 and the secondary transfer belt 72 between itself and the secondary transfer roller 70, forming a secondary transfer nip. The four-color toner images formed on the intermediate transfer belt 8 are then secondarily transferred onto a sheet P such as paper transported to the position of this secondary transfer nip (secondary transfer process). At this time, untransferred toner that has not been transferred to the sheet P remains on the intermediate transfer belt 8.

[0019] Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, any untransferred toner or other adhering matter adhering to the surface of the intermediate transfer belt 8 is removed. Thus, the series of transfer processes performed on the intermediate transfer belt 8 is completed.

[0020] Referring to FIG. 1, the sheet P transported to the secondary transfer nip position is transported from a paper feed section 26 disposed below the device main body 100 via a paper feed roller 27, a pair of registration rollers 28, etc. More specifically, a plurality of sheets P are stacked and stored in the paper feed unit 26. When the paper feed roller 27 is rotated counterclockwise in FIG. 1, the topmost sheet P is fed through the first transport path K1 toward between the rollers of the registration roller pair 28.

[0021] The sheet P conveyed to the registration roller pair 28 (timing roller pair) is temporarily stopped at the roller nip position of the registration roller pair 28, which has stopped rotating. Then, the registration roller pair 28 is rotated in synchronization with the color image on the intermediate transfer belt 8, and the sheet P is conveyed toward the secondary transfer nip. In this way, the desired color image is transferred onto the sheet P.

[0022] Thereafter, the sheet P onto which the color image has been transferred at the secondary transfer nip position is conveyed by the secondary transfer belt 72, and after being separated from the secondary transfer belt 72, is conveyed by the conveying belt 60 to the position of the fixing unit 50. Then, at this position, the color image transferred onto the surface is fixed onto the sheet P by the heat and pressure of the fixing belt and pressure roller (fixing process). Thereafter, the sheet P passes through the second transport path K2 and is discharged to the outside of the apparatus by the pair of discharge rollers. The sheets P discharged to the outside of the apparatus by the pair of discharge rollers are sequentially stacked on a stack unit as output images. In this way, a series of image forming operations (printing operations) in the image forming apparatus is completed.

[0023] When a "double-sided print mode" is selected in which printing is performed on both sides (front and back sides) of the sheet P, the sheet P after the fixing process on the front side is not discharged as is as when the above-mentioned "single-sided print mode" is selected, but is guided to the third transport path K3, its transport direction is reversed, and then it is transported again toward the position of the secondary transfer nip (secondary transfer belt device 69) via the fourth transport path K4. Then, at the position of the secondary transfer nip, an image is formed on the back side of the sheet P by the same image formation process (image forming operation) as described above, and then the sheet P undergoes a fixing process in the fixing unit 50 and is discharged from the image forming apparatus main body 100 via the second transport path K2.

[0024] Next, the configuration and operation of the developing unit 5Y (developing device) in the image forming unit will be described in more detail with reference to FIG. The developing unit 5Y is composed of a developing roller 51Y facing the photosensitive drum 1Y, a doctor blade 52Y facing the developing roller 51Y, two conveying screws 55Y disposed in the developer container, and a concentration detection sensor 56Y that detects the toner concentration in the developer. The developing roller 51Y is composed of a magnet fixed inside and a sleeve that rotates around the magnet. The developer container contains a two-component developer G consisting of carrier and toner.

[0025] The developing section 5Y configured in this manner operates as follows. The sleeve of the developing roller 51Y rotates in the direction of the arrow in FIG. 2. The developer G carried on the developing roller 51Y by the magnetic field generated by the magnet moves on the developing roller 51Y as the sleeve rotates. The developer G in the developing unit 51Y is adjusted so that the ratio of toner in the developer G (toner concentration) falls within a predetermined range. Specifically, when a toner concentration sensor installed in the developing unit 5Y detects that the toner concentration is low, new toner is replenished from the toner container 58 into the developing unit 5Y so that the toner concentration falls within the predetermined range. Thereafter, the toner supplied from the toner container 58 to the developer storage section circulates between the two separated developer storage sections (movement in the direction perpendicular to the plane of the paper in FIG. 2) while being mixed and stirred by the two transport screws 55Y together with the developer G. Then, the toner in the developer G is attracted to the carrier due to frictional charging with the carrier, and is carried on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

[0026] The developer G carried on the developing roller 51Y is transported in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. The developer G on the developing roller 51Y is then adjusted to an appropriate amount at this position, and then transported to a position facing the photosensitive drum 1Y (the developing area). The toner is then attracted to the latent image formed on the photosensitive drum 1Y by an electric field formed in the developing area. Thereafter, the developer G remaining on the developing roller 51Y reaches above the developer storage section as the sleeve rotates, and is separated from the developing roller 51Y at this position. The toner container 58 is detachably (replaceably) installed in the developing unit 5Y (image forming apparatus 100). When the new toner stored therein becomes empty, the toner container 58 is removed from the developing unit 5Y (image forming apparatus 100) and replaced with a new toner.

[0027] Next, the intermediate transfer belt device 15 as a belt device will be described in detail. Referring to Figure 3, the intermediate transfer belt device 15 (belt device) is composed of an intermediate transfer belt 8 as a belt member, four primary transfer rollers 9Y, 9M, 9C, and 9K, a drive roller 16, a correction roller 17 (driven roller), a pre-transfer roller 18, a tension roller 19, an intermediate transfer cleaning unit 10, a secondary transfer opposing roller 40, etc. Intermediate transfer belt 8, which serves as a belt member, contacts four photosensitive drums 1Y, 1M, 1C, and 1K, each carrying a toner image of each color, to form a primary transfer nip. Intermediate transfer belt 8 is stretched and supported mainly by five roller members (drive roller 16, correction roller 17, pre-transfer roller 18, tension roller 19, and secondary transfer opposing roller 40).

[0028] In this embodiment, the intermediate transfer belt 8 is made of a single layer or multiple layers of PVDF (vinyl fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC (polycarbonate), PAI (polyamide imide), TPE (thermoplastic elastomer), PEEK (polyether ether ketone), or the like, with a conductive material such as carbon black dispersed therein. The intermediate transfer belt 8 has a volume resistivity of 10 6 ~10 13 Ωcm, the surface resistivity of the back side of the belt is 10 7 ~10 13 The intermediate transfer belt 8 is adjusted to have a thickness in the range of 20 to 200 μm. In this embodiment, the thickness of the intermediate transfer belt 8 is set to about 60 μm, and the volume resistivity is set to 10 9 It is set to about Ωcm. If necessary, a release layer can be coated on the surface of the intermediate transfer belt 8. In this case, fluororesins such as ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PVDF (vinyldiene fluoride), PEA (perfluoroalkoxy fluororesin), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and PVF (vinyl fluoride) can be used as the material for the coating, but the material is not limited to these.

[0029] The primary transfer rollers 9Y, 9M, 9C, and 9K are in contact with the corresponding photosensitive drums 1Y, 1M, 1C, and 1K, respectively, via the intermediate transfer belt 8. More specifically, the yellow transfer roller 9Y is in contact with the yellow photosensitive drum 1Y via the intermediate transfer belt 8, the magenta transfer roller 9M is in contact with the magenta photosensitive drum 1M via the intermediate transfer belt 8, the cyan transfer roller 9C is in contact with the cyan photosensitive drum 1C via the intermediate transfer belt 8, and the black transfer roller 9K is in contact with the black photosensitive drum 1K via the intermediate transfer belt 8. The primary transfer rollers 9Y, 9M, 9C, and 9K are elastic rollers each having a conductive sponge layer formed on a core metal, and each having a volume resistance of 10 6 ~1012 Ω (preferably 10 7 ~10 9 It is adjusted to be in the range of Ω.

[0030] The drive roller 16 is disposed downstream of the four photosensitive drums in the running direction of the intermediate transfer belt, and is in contact with the inner circumferential surface of the intermediate transfer belt 8 with the intermediate transfer belt 8 wrapped around it at a wrap angle of approximately 120 degrees. The drive roller 16 is driven to rotate in the clockwise direction in FIG. 3 by a drive motor Mt1 controlled by the control unit 90. This causes the intermediate transfer belt 8 to run in a predetermined running direction (clockwise in FIG. 3).

[0031] The correction roller 17 is disposed upstream of the four photosensitive drums in the running direction of the intermediate transfer belt 8, and is disposed so as to abut against the inner circumferential surface of the intermediate transfer belt 8 with the intermediate transfer belt 8 wrapped around it at a wrapping angle of approximately 180 degrees. The portion of the intermediate transfer belt 8 from the correction roller 17 to the drive roller 16 is set to be a substantially horizontal plane. The correction roller 17 is rotated clockwise in FIG. 3 as the intermediate transfer belt 8 runs. The correction roller 17 is used to correct the belt deviation (belt movement in the width direction) of the intermediate transfer belt 8, which will be described in detail later.

[0032] An intermediate transfer cleaning unit 10 is installed at the position of the correction roller 17. A cleaning blade 85 is installed in the intermediate transfer cleaning unit 10 so as to contact the correction roller 17 via the intermediate transfer belt 8. The cleaning blade 85 contacts the intermediate transfer belt 8 at a predetermined contact angle and pressure. The tension roller 19 is in contact with the outer circumferential surface of the intermediate transfer belt 8. The pre-transfer roller 18 and the secondary transfer opposing roller 40 are in contact with the inner circumferential surface of the intermediate transfer belt 8. All of the roller members 17 to 19 and 40 except for the drive roller 16 are driven to rotate in the clockwise direction in FIG. 3 as the intermediate transfer belt 8 moves.

[0033] 3, the secondary transfer opposing roller 40 is in contact with the secondary transfer roller 70 via the intermediate transfer belt 8 and the secondary transfer belt 72. The secondary transfer opposing roller 40 is a cylindrical core metal made of stainless steel or the like, and has a volume resistance of 10 7 ~10 8 An elastic layer (thickness: about 5 mm) made of NBR rubber having a hardness (JIS-A hardness) of about 48 to 58 degrees is formed.

[0034] In the present embodiment, the secondary transfer opposing roller 40 is electrically connected to a power supply unit 91, and a secondary transfer bias of a high voltage of about −5 kV is applied from the power supply unit 91. The secondary transfer bias applied to the secondary transfer opposing roller 40 is for secondarily transferring the toner image that has been primarily transferred onto the surface of the intermediate transfer belt 8 onto the sheet P being conveyed to the secondary transfer nip, and is a secondary transfer bias (DC voltage) of the same polarity as that of the toner (negative polarity in the present embodiment). As a result, the toner carried on the toner carrying surface (outer peripheral surface) of the intermediate transfer belt 8 is electrostatically moved from the secondary transfer opposing roller 40 side toward the secondary transfer belt device 69 side by the secondary transfer electric field.

[0035] The secondary transfer belt device 69 is made up of a secondary transfer belt 72, a secondary transfer roller 70, a driven roller 71, a secondary transfer blade 73 (cleaning blade), and the like. The secondary transfer roller 70 is driven to rotate in the counterclockwise direction in Fig. 3 by a motor Mt2 controlled by the control unit 90, causing the secondary transfer belt 72 to rotate (run) in the counterclockwise direction in Fig. 3, and also causing the driven roller 71 to rotate counterclockwise in Fig. 3. In other words, the secondary transfer roller 70 functions as a drive roller that drives the secondary transfer belt 72 as a belt member. The driven roller 71 is disposed at a position downstream of the secondary transfer nip in the transport direction (downstream of the transport direction of the sheet P). The sheet P sent out from the secondary transfer nip is transported along the secondary transfer belt 72 traveling counterclockwise in FIG. 3, and then separated from the secondary transfer belt 72 at the position of the driven roller 71 by the secondary transfer belt 72, which has a curved surface formed along the outer periphery of the driven roller 71 (curvature separation). In this way, the driven roller 71 also functions as a separation roller. The secondary transfer blade 73 comes into contact with the surface of the secondary transfer belt 72 to remove foreign matter such as toner and paper dust adhering to the surface of the secondary transfer belt 72 .

[0036] The configuration and operation of intermediate transfer belt device 15 as a belt device in this embodiment will be described in detail below. Referring to Figures 4, 6, 8, etc., in the intermediate transfer belt device 15 (belt device) of this embodiment, the intermediate transfer belt 8 (belt member) is stretched and supported by a plurality of roller members 9Y, 9M, 9C, 9K, 16 to 19, and 40, and a correction mechanism 79 is provided that tilts one of the plurality of roller members (the correction roller 17) with respect to the width direction (the rotation axis direction). The correction mechanism 79 tilts the correction roller 17 in conjunction with the movement of the intermediate transfer belt 8 in the width direction, thereby correcting the belt deviation of the intermediate transfer belt 8.

[0037] 4, the correction roller 17 (one of the roller members) has a roller portion 17a that contacts the inner circumferential surface of the intermediate transfer belt 8, and a shaft portion 17b (roller shaft) that has a smaller outer diameter than the roller portion 17a and protrudes from both ends of the roller portion 17a. The shaft portion 17b can be formed by using two shaft portions 17b that protrude separately from both ends of the roller portion 17a, or one shaft portion 17b can be formed by passing through the roller portion 17a and protruding from both ends. In either case, the correction roller 17 in this embodiment has the roller portion 17a and the shaft portion 17b integrated with each other and rotate together. 4, the intermediate transfer belt device 15 is provided with bearings 76 that support the shaft portion 17b of the correction roller 17. The shaft portions 17b at both ends of the correction roller 17 are rotatably held by swinging side plates 75 (see FIG. 5) serving as holding members via the bearings 76, respectively. It is also possible to configure the correction roller 17 so that a ball bearing is press-fitted onto the shaft portion 17b thereof, and the swinging side plate 75 rotatably holds the ball bearing via a bearing (for example, a sliding bearing made of resin).

[0038] 8 and other drawings, the shafts of the other roller members such as the drive roller 16 are rotatably held by a housing 74 of the intermediate transfer belt device 15 via bearings at both ends. The swinging side plate 75, together with the correction roller 17, is held by the housing 74 so as to be rotatable in the direction of the arrow in FIG. 5 around a support shaft 75b. The swinging side plate 75 is configured to be biased in the clockwise direction in FIG. 5 by a tension spring 78 (biasing member) connected between the swinging side plate 75 and the housing. Furthermore, the shaft 17b of the correction roller 17 is rotatably held in the guide holes 75a of the swinging side plates 75 on both ends via bearings 76. The bearings 76 are slidably held in the guide holes 75a and are biased leftward in FIG. 5 by a compression spring 77. With this configuration, the correction roller 17 is pressed against the inner circumferential surface of the intermediate transfer belt 8 by the biasing force of the compression spring 77, thereby applying tension to the intermediate transfer belt 8.

[0039] As shown in FIGS. 4, 6, etc., the correction mechanism 79 is made up of a flange 80 (abutting member), a sliding member 81 (a guided portion), a contact member 82 (a guide portion), and the like. The sliding member 81 is supported slidably on the shaft portion 17b of the correction roller 17 (one roller member), and tilts the correction roller 17 (shaft portion 17b) in conjunction with the movement (toward the belt) of the intermediate transfer belt 8 in the width direction (left and right direction in Figures 4 and 6). A parallel surface 81a that is parallel to the rotation axis direction and an inclined surface 81b that is inclined relative to the parallel surface 81a are formed on the sliding member 81. The abutting member 82 abuts against the parallel surface 81a and the inclined surface 81b. Furthermore, the sliding member 81 is configured not to rotate in response to the movement of the intermediate transfer belt 8 or the rotation of the correction roller 17 (shaft 17b). Specifically, the sliding member 81 is locked to a rotation-stopping protrusion formed on the housing 74 of the device, thereby restricting its rotation. In addition, when a ball bearing is press-fitted onto the shaft portion 17b of the correction roller 17 and the swinging side plate 75 is configured to rotatably hold the ball bearing via a bearing (for example, a sliding bearing made of resin), a protrusion for preventing rotation can also be formed on the bearing.

[0040] The contact member 82 is formed so as to be able to come into contact with the parallel surface 81a and the inclined surface 81b of the sliding member 81. Then, as the intermediate transfer belt 8 moves in the width direction, the inclined surface 81b of the sliding member 81 and the contact member 82 slide against each other, thereby tilting the correction roller 17 (shaft portion 17b). The flange 80 is disposed so as to be able to abut against the end surface of the intermediate transfer belt 8, and is pushed and moved by the intermediate transfer belt 8 as the intermediate transfer belt 8 moves in the width direction. The flange 80 is configured so as to be rotatable (able to rotate together) as the intermediate transfer belt 8 runs and as the correction roller 17 (shaft portion 17b) rotates. The sliding member 81 is disposed so as to be able to abut against the flange 80 at a position opposite to the intermediate transfer belt 8.

[0041] Further, the correction mechanism 79 will be explained in more detail. The flange 80 is slidably and rotatably held on the shaft portion 17b of the correction roller 17. The flange 80 is formed with an abutment portion 80a against which the end face of the intermediate transfer belt 8 abuts when the intermediate transfer belt 8 deviates from the belt. The abutment portion 80a is formed with an outer diameter sufficiently larger than the outer diameter of the correction roller 17 (roller portion 17a) so that the intermediate transfer belt 8 does not ride up. The flange 80 rotates as the correction roller 17 rotates. The sliding member 81 is slidably and non-rotatably installed on the shaft portion 17b of the correction roller 17 at a position outside the flange 80 in the width direction. The sliding member 81 is formed with a parallel surface 81a and an inclined surface 81b. The sliding member 81 does not rotate even when the correction roller 17 rotates. The abutting member 82 is non-rotatably installed at a fixed position on the shaft portion 17b so as to face the sliding member 81.

[0042] The correction mechanism 79 configured in this manner corrects the belt deviation of the intermediate transfer belt 8 (the belt movement in the left and right directions in FIGS. 4 and 6). The basic mechanism will be explained below. As shown in Figure 7(A), it is assumed that the parallelism between the drive roller 16 and the correction roller 17 has shifted. In Figure 7(A), the right end of the correction roller 17 is tilted in the -X direction (toward the viewer in the direction perpendicular to the paper surface) relative to the drive roller 16. In this case, the intermediate transfer belt 8 is tilted to the right at an inclination angle θ when viewed from the correction roller 17 side, and when the intermediate transfer belt 8 advances a distance Y, the belt is shifted to the right by an amount Y tan θ. When the intermediate transfer belt 8 deviates to the right, as shown in Fig. 6(A), the end face of the intermediate transfer belt 8 abuts against the abutment portion 80a of the flange 80, causing the flange 80 to slide rightward and push the sliding member 81 rightward. When the sliding member 81 is pushed rightward, the abutment member 82, which has been abutting against the parallel surface 81a as shown in Fig. 6(A), abuts against the inclined surface 81b as shown in Fig. 6(B), causing the correction roller 17 to tilt along the inclination of the inclined surface 81b as shown in Figs. 6(B) and 7(B). 7(B) (and FIG. 6(B)), when the right end of the correction roller 17 is tilted in the +X direction (toward the rear in the direction perpendicular to the paper surface), the intermediate transfer belt 8 tilts leftward at an inclination angle θ' when viewed from the correction roller 17 side, and when the intermediate transfer belt 8 advances a distance Y, the belt shifts leftward by Ytan θ', thereby canceling out the belt shift to the right. In this way, the belt shift of the intermediate transfer belt 8 is corrected by the correction mechanism 79.

[0043] By using the correction mechanism 79 configured in this way, the intermediate transfer belt 8 is less likely to become misaligned. In particular, in this embodiment, the correction roller 17 (shaft portion 17b) can be tilted by a simple and space-saving configuration in which the contact member 82 is simply slid relatively on the inclined surface 81b of the sliding member 81. Furthermore, in this embodiment, a flange 80 configured and operating as described above is provided between the intermediate transfer belt 8 and the sliding member 81, so that the force of the intermediate transfer belt 8 shifting in the width direction can be transmitted directly to the sliding member 81 by the flange 80, thereby enabling stable belt shift correction. Furthermore, in this embodiment, the flange 80 is configured to be co-rotatable, and the intermediate transfer belt 8 and the flange 80 do not rub against each other, thereby reducing the problem of wear on the end surface of the intermediate transfer belt 8. Furthermore, since the sliding member 81 does not rotate, it is not necessary to form the inclined surface 81b or the parallel surface 81a in the rotational direction, and this prevents the sliding member 81 from becoming too large. Although not shown in Figures 8 and 9, in this embodiment, the correction mechanism 79 is not only installed at one end side in the width direction (lower side in Figure 8), but also at the other end side in the width direction (upper side in Figure 8).

[0044] The following will describe in detail the more characteristic configuration and operation of the intermediate transfer belt device 15 as a belt device in this embodiment. As explained above using Figure 4 etc., the intermediate transfer belt device 15 (belt device) in this embodiment is provided with a correction mechanism 79 that tilts one roller member (correction roller 17) among multiple roller members that stretch and support the intermediate transfer belt 8 in conjunction with the movement of the intermediate transfer belt 8 (belt member) in the width direction (the left-right direction in Figure 4). The intermediate transfer belt device 15 is also provided with a swinging side plate 75 as a holding member that rotatably holds the shaft portion 17b of the correction roller 17 (one roller member).

[0045] Now, referring to Figure 4 etc., in the intermediate transfer belt device 15 in this embodiment, a screw member 87 as a regulating member for regulating the widthwise movement of the correction roller 17 (one roller member) is arranged on the shaft portion 17b of the correction roller 17 on the outer side in the widthwise direction (to the right in Figure 4) of the oscillating side plate 75 (holding member) so as to be able to indirectly (or directly) contact the oscillating side plate 75. The screw member 87 as a regulating member is fixed to the shaft portion 17b so as to be rotatable integrally with the correction roller 17 (one roller member).

[0046] 4, a substantially doughnut-shaped intermediate member 86, at least the surface of which is made of a low-friction material (such as a fluororesin material), is provided between the swinging side plate 75 (holding member) and the screw member 87 (regulating member) on the shaft portion 17b of the correction roller 17. That is, the screw member 87 as a regulating member is disposed so as to be able to indirectly come into contact with the swinging side plate 75 via the intermediate member 86. The screw member 87 serving as a restricting member is made of a metal material that is resistant to wear and deterioration, and its male thread is screwed into the screw hole 17b1 (formed inward from the end face of the shaft portion 17b).

[0047] The screw member 87 (screw head) serving as a restricting member is formed so that its outer diameter is larger than the shaft diameter of the shaft portion 17b (or the inner diameter of the bearing 76) and larger than the inner diameter of the intermediate member 86. As a result, even when the screw member 87 rotates together with the correction roller 17 (shaft portion 17b), the screw member 87 does not slide against the oscillating side plate 75, but slides against the intermediate member 86 made of a low-friction material, so that the screw member 87 is less likely to wear out. Furthermore, since the screw member 87 has a larger shaft diameter than the shaft portion 17b, even if the correction roller 17 (shaft portion 17b) moves to the left side of Figure 4, the screw member 87 comes into contact with the swinging side plate 75 via the intermediate member 86, thereby restricting the movement (the screw member 87 functions as a regulating member).

[0048] As described above, in the present embodiment, the screw member 87 as a regulating member is fixed to the shaft portion 17b so as to be rotatable integrally with the correction roller 17, and therefore, the screw member 87 (regulating member) does not rotate as the correction roller 17 rotates but slides against the correction roller 17, preventing a problem in which the screw member 87 and the correction roller 17 are worn out. Therefore, a problem in which the function of correcting the belt deviation of the intermediate transfer belt 8 is not easily achieved due to wear of the screw member 87 (regulating member) and the correction roller 17 is also prevented. 10 as a comparative example, if an E-ring 187 (retaining ring) is installed in a groove formed in the shaft portion 117b and the E-ring 187 is used to restrict the movement of the correction roller 117 in the width direction, when the bias of the intermediate transfer belt 8 becomes strong, the friction between the correction roller 117 (groove in the shaft portion 117b) and the E-ring 187 increases over time, regardless of whether the intermediate member 86 is present, and the E-ring 187 no longer rotates integrally with the correction roller 117, causing wear (abrasion) due to sliding between the E-ring 187 and the correction roller 117. When the wear (abrasion) of the E-ring 187 and the correction roller 117 progresses in this way, the correction roller 117 shifts unexpectedly in the width direction, so that the correction roller 117 pushes the flange 80 on the opposite side, and the flange 80 further pushes the sliding member 81, causing the sliding member on the opposite side to butt against the abutting member 82 and tilt the correction roller 117. If the correction roller 117 is tilted in this way, the correction roller 117 will be tilted in the direction that accelerates the belt shift, which will cause the balance of the belt shift control by the correction mechanism 79 to be lost, and a load will be placed on the intermediate transfer belt 8, causing problems such as damage. In contrast to this, in the present embodiment, the screw member 87 as a regulating member is fixed to the shaft portion 17b so as to be rotatable integrally with the correction roller 17, thereby suppressing wear (abrasion) between the correction roller 17 and the screw member 87 (regulating member), and therefore the belt deviation control by the correction mechanism 79 is maintained stably for a long period of time.

[0049] In this embodiment, an intermediate member 86 made of a low-friction material is installed between the swinging side plate 75 and the screw member 87 (regulating member), but it is also possible to form at least the surface (the surface that comes into contact with the swinging side plate 75) of the screw member 87 (regulating member) from a low-friction material without installing such an intermediate member 86. In this case, the screw member 87 as a regulating member is positioned so that it can come into direct contact with the swinging side plate 75, but since its surface is formed of a low-friction material, the screw member 87 is less likely to wear out.

[0050] In this embodiment, the screw member 87 (restriction member) is detachably installed on the shaft portion 17b. Specifically, by screwing and unscrewing the screw member 87 into and from the screw hole 17b1 of the shaft portion 17b, the screw member 87 can be easily attached to and detached from the shaft portion 17b. By configuring the screw member 87 (restriction member) to be detachable in this manner, maintenance and replacement of the screw member 87 (restriction member) can be easily performed.

[0051] <Variation 1> As shown in FIG. 11, in the intermediate transfer belt device 15 (belt device) in the first modification, the regulating member 88 is adhered or welded to the end (end surface W) of the shaft portion 17b of the correction roller 17. This regulating member 88 is a roughly disk-shaped member made of a metal material, and is formed so that its outer diameter is larger than the shaft diameter of the shaft portion 17b (or the inner diameter of the bearing 76) and larger than the inner diameter of the intermediate member 86. Even when such a regulating member 88 is used, the regulating member 88 that regulates the movement of the correction roller 17 (roller member) in the width direction, which is inclined by the correction mechanism 79, and the correction roller 17 are less likely to wear out. In the first modification, the restricting member 88 can also be fixed to the end of the shaft portion 17b by caulking.

[0052] <Variation 2> As shown in FIG. 12, in the intermediate transfer belt device 15 of the second modification, a cap member 89 as a regulating member is press-fitted onto the end of the shaft portion 17b of the correction roller 17. This cap member 89 is made of a metal material and has a recess formed therein that can be press-fitted (fixed) onto the shaft portion 17b, and is formed so that its outer diameter is larger than the shaft diameter of the shaft portion 17b (or the inner diameter of the bearing 76) and larger than the inner diameter of the intermediate member 86. Even when such a cap member 89 is used, the regulating member 88 that regulates the movement of the correction roller 17 (roller member) in the width direction, which is inclined by the correction mechanism 79, and the correction roller 17 are less likely to wear out.

[0053] As described above, the intermediate transfer belt device 15 (belt device) of this embodiment includes the intermediate transfer belt 8 (belt member) stretched and supported by a plurality of roller members, the correction mechanism 79 that tilts the correction roller 17 (one roller member) of the plurality of roller members in conjunction with the movement of the intermediate transfer belt 8 in the width direction, and the swinging side plate 75 (holding member) that rotatably holds the shaft portion 17b of the correction roller 17. Furthermore, the screw member 87 (regulating member) that regulates the movement of the correction roller 17 in the width direction is disposed on the shaft portion 17b on the outer side of the swinging side plate 75 in the width direction so as to be in indirect or direct contact with the swinging side plate 75. The screw member 87 is fixed to the shaft portion 17b so as to be rotatable integrally with the correction roller 17. This makes it possible to prevent wear of the screw member 87 (regulating member) that regulates the movement of the correction roller 17 (roller member) in the width direction when the correction roller 17 is tilted by the correction mechanism 79, and the correction roller 17.

[0054] In this embodiment, the present invention is applied to the intermediate transfer belt device 15 that corrects the belt shift of the intermediate transfer belt 8 as a belt member, but the application of the present invention is not limited to this. For example, the present invention can be applied not only to the secondary transfer belt device 69 in which the secondary transfer belt 72 is installed in this embodiment, but also to belt devices in which other belt members such as a photosensitive belt, a transfer conveying belt, and a fixing belt are installed. In the present embodiment, the present invention is applied to the image forming apparatus 100 that forms color images. However, the present invention can also be applied to an image forming apparatus that forms only monochrome images. Even in such cases, the same effects as those of this embodiment can be obtained.

[0055] It is to be noted that the present invention is not limited to the present embodiment, and it is clear that the present embodiment can be appropriately modified within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. of the components can be any number, position, shape, etc. that is suitable for implementing the present invention. [Explanation of symbols]

[0056] 8 intermediate transfer belt (belt member), 15 Intermediate transfer belt device (belt device), 17 correction roller (one roller member), 75 Swinging side plate (holding member), 79 Correction mechanism, 80 flange (butting member), 81 sliding member (guided portion), 81a parallel plane, 81b inclined plane, 82 contact member (guide portion), 86 intermediate members, 87 Screw member (regulating member), 88 Regulatory members, 89 Cap member, 100 Image forming apparatus (image forming apparatus main body).

[0057] The present invention can also be embodied in a combination of Supplementary Notes 1 to 14, for example, as follows. (Appendix 1) a belt member stretched and supported by a plurality of roller members; a correction mechanism that tilts one of the plurality of roller members in conjunction with the movement of the belt member in the width direction; a holding member that rotatably holds a shaft portion of the one roller member; a regulating member that is disposed on the shaft portion on the outer side of the holding member in the width direction so as to be indirectly or directly in contact with the holding member and that regulates movement of the one roller member in the width direction; Equipped with The belt device is characterized in that the regulating member is fixed to the shaft portion so as to be rotatable integrally with the one roller member. (Appendix 2) 2. The belt device according to claim 1, wherein an intermediate member, at least the surface of which is made of a low-friction material, is provided between the holding member and the regulating member on the shaft portion. (Appendix 3) 3. The belt device according to claim 2, wherein the outer diameter of the regulating member is larger than the inner diameter of the intermediate member. (Appendix 4) 4. The belt device according to claim 1, wherein at least the surface of the regulating member is made of a low-friction material. (Appendix 5) 5. The belt device according to claim 1, wherein the regulating member is detachably attached to the shaft portion. (Appendix 6) 6. The belt device according to any one of claims 1 to 5, wherein the regulating member is a screw member that is screwed into a screw hole formed on the end surface of the shaft portion. (Appendix 7) 5. The belt device according to claim 1, wherein the regulating member is press-fitted onto an end of the shaft portion. (Appendix 8) 5. The belt device according to claim 1, wherein the regulating member is bonded or welded to the end of the shaft portion. (Appendix 9) 5. The belt device according to claim 1, wherein the regulating member is crimped to an end of the shaft portion. (Appendix 10) 10. The belt device according to any one of claims 1 to 9, wherein the regulating member is made of a metal material. (Appendix 11) The correction mechanism includes: a sliding member slidably supported on the roller shaft of the one roller member and having an inclined surface; a contact member formed to be able to contact the inclined surface of the sliding member; Equipped with The belt device according to any one of Supplementary Note 1 to Supplementary Note 10, characterized in that the inclined surface of the sliding member and the contact member slide in conjunction with the movement of the belt member in the width direction, thereby inclining the one roller member. (Appendix 12) a flange disposed so as to be able to come into contact with an end surface of the belt member, and which is pushed and moved by the belt member as the belt member moves in the width direction; 12. The belt device according to claim 11, wherein the sliding member is disposed so as to be able to abut against the flange at a position opposite to the belt member. (Appendix 13) The flange is configured to be rotatable as the belt member travels, 13. The belt device according to claim 12, wherein the sliding member is configured not to rotate as the belt member travels. (Appendix 14) An image forming apparatus comprising the belt device according to any one of Supplementary Notes 1 to 13. [Prior art documents] [Patent documents]

[0058] [Patent Document 1] Japanese Patent Application Publication No. 2023-107459

Claims

1. a belt member stretched and supported by a plurality of roller members; a correction mechanism that tilts one of the plurality of roller members in conjunction with the movement of the belt member in the width direction; a holding member that rotatably holds a shaft portion of the one roller member; a restricting member disposed on the shaft portion on the outer side of the holding member in the width direction so as to be indirectly or directly in contact with the holding member, and restricting movement of the one roller member in the width direction; Equipped with The belt device is characterized in that the regulating member is fixed to the shaft portion so as to be rotatable integrally with the one roller member.

2. 2. The belt device according to claim 1, wherein an intermediate member, at least the surface of which is made of a low-friction material, is provided between the holding member and the regulating member on the shaft portion.

3. 3. The belt device according to claim 2, wherein the outer diameter of the regulating member is larger than the inner diameter of the intermediate member.

4. 2. The belt device according to claim 1, wherein at least the surface of the regulating member is made of a low-friction material.

5. 3. The belt device according to claim 1, wherein the regulating member is detachably attached to the shaft portion.

6. 3. The belt device according to claim 1, wherein the regulating member is a screw member that is threaded into a screw hole formed in an end surface of the shaft portion.

7. 3. The belt device according to claim 1, wherein the regulating member is press-fitted onto an end of the shaft portion.

8. 3. The belt device according to claim 1, wherein the regulating member is adhered or welded to the end of the shaft portion.

9. 3. The belt device according to claim 1, wherein the regulating member is crimped to an end of the shaft portion.

10. 3. The belt device according to claim 1, wherein the regulating member is made of a metal material.

11. The correction mechanism includes: a sliding member slidably supported on the roller shaft of the one roller member and having an inclined surface; a contact member formed to be able to contact the inclined surface of the sliding member; Equipped with 3. The belt device according to claim 1, wherein the inclined surface of the sliding member and the contact member slide in conjunction with the movement of the belt member in the width direction, thereby inclining the one roller member.

12. a flange disposed so as to be able to come into contact with an end surface of the belt member, and which is pushed and moved by the belt member as the belt member moves in the width direction; 12. The belt device according to claim 11, wherein the sliding member is disposed so as to be able to abut against the flange at a position opposite to the belt member.

13. The flange is configured to be rotatable as the belt member travels, 13. The belt device according to claim 12, wherein the sliding member is configured not to rotate as the belt member travels.

14. 3. An image forming apparatus comprising the belt device according to claim 1.

Images