Belt driving device and image forming apparatus including the same

Abstract

To provide a belt driving device that can reduce deterioration of an intermediate transfer belt while reducing manufacturing costs, and an image forming apparatus including the same.SOLUTION: A belt driving device comprises: an endless belt; a plurality of stretch rollers that rotatably stretch the belt; and a belt cleaning device. The belt cleaning device has a cleaning blade and an opposing roller. The cleaning blade is in contact with an outer peripheral surface of the belt to remove a foreign substance attached to the belt. The opposing roller is arranged opposite to the cleaning blade with the belt held in between and in contact with an inner peripheral surface of the belt. The opposing roller has a cover layer arranged on its outer peripheral surface, a surface resistance value of the cover layer when 100 V voltage is applied is the tenth power (Ω) of 10 or more, and the Asker A hardness of the cover layer is 60° or more and 90° or less.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a belt driving device and an image forming apparatus including the same. [Background technology]

[0002] A conventional belt driving device is equipped with a belt cleaning device that removes residual toner adhering to an intermediate transfer belt onto which a toner image formed on a photosensitive drum (image carrier) is transferred. The belt cleaning device has a cleaning blade that removes residual toner adhering to the belt (intermediate transfer belt), an opposing roller that faces the cleaning blade across the belt and is arranged so as to contact the inner circumferential surface of the belt, and an electrode member. The pressing force of the cleaning blade is received by the opposing roller. A voltage having a predetermined frequency is applied to the electrode member.

[0003] By applying a voltage to the electrode member, the opposing roller and the belt are vibrated, and the residual toner adhering to the belt is removed by the cleaning blade. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-107916 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the belt driving device disclosed in the above-mentioned patent document has a possibility of the belt being deteriorated due to the voltage of the electrode member, and the manufacturing cost may increase due to the provision of a vibration mechanism such as the electrode member.

[0006] In view of the above problems, an object of the present invention is to provide a belt driving device capable of reducing belt deterioration while suppressing manufacturing costs, and an image forming apparatus including the same. [Means for solving the problem]

[0007] An exemplary belt driving device of the present invention includes an endless belt, a plurality of tension rollers that rotatably tension the belt, and a belt cleaning device. The belt cleaning device includes a cleaning blade and an opposing roller. The cleaning blade contacts the outer peripheral surface of the belt to remove foreign matter attached to the belt. The opposing roller is disposed so as to face the cleaning blade across the belt and contact the inner peripheral surface of the belt. The opposing roller has a cover layer disposed on the outer peripheral surface, and when a voltage of 100 V is applied, the surface resistance of the cover layer is 10 to the power of 10 (Ω) or more, and the Asker A hardness of the cover layer is 60° or more and 90° or less. Effect of the Invention

[0008] According to an exemplary embodiment of the present invention, it is possible to provide a belt driving device capable of reducing belt deterioration while suppressing manufacturing costs, and an image forming apparatus including the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic structure of an image forming apparatus 100 including an intermediate transfer unit 25 according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a side cross-sectional view showing a structure around an intermediate transfer unit according to an embodiment of the present invention. [Diagram 3] FIG. 1 is a side cross-sectional view showing a structure around a belt cleaning device 30 constituting an intermediate transfer unit 25 according to an embodiment of the present invention. [Figure 4] A graph showing the relationship between the cumulative number of prints of the image adjustment pattern transferred to the intermediate transfer belt 8 according to one embodiment of the present invention and the density unevenness of the image adjustment pattern transferred to the intermediate transfer belt 8. [Diagram 5] Graph showing change in surface roughness in the longitudinal direction of intermediate transfer belt 8 according to one embodiment of the present invention. [Figure 6]FIG. 1 is an explanatory diagram for explaining a method for evaluating deterioration of an intermediate transfer belt 8 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing the internal structure of an image forming apparatus 100 according to one embodiment of the present invention. Within the main body of the image forming apparatus 100 (here, a color printer), four image forming sections Pa, Pb, Pc, and Pd are arranged in this order from the upstream side in the transport direction (the left side in Fig. 1). The image forming sections Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and sequentially form images of cyan, magenta, yellow, and black through the processes of charging, exposure, development, and transfer, respectively.

[0011] The image forming units Pa to Pd are provided with photosensitive drums (image carriers) 1a, 1b, 1c and 1d that carry visible images (toner images) of each color, and further provided adjacent to each image forming unit Pa to Pd is an intermediate transfer belt 8 that rotates counterclockwise in FIG. 1 by a belt drive motor (not shown).

[0012] The toner images formed on the photoconductor drums 1a to 1d are sequentially primarily transferred and superimposed on an intermediate transfer belt 8 that moves while contacting each of the photoconductor drums 1a to 1d. Thereafter, the toner images primarily transferred onto the intermediate transfer belt 8 are secondarily transferred by a secondary transfer roller 9 onto a sheet of paper P, which is an example of a recording medium. The sheet of paper P onto which the toner images have been secondarily transferred is discharged from the main body of the image forming apparatus 100 after the toner images have been fixed in a fixing unit 13. At this time, each of the photoconductor drums 1a to 1d rotates clockwise in FIG. 1, and an image forming process is performed for each of the photoconductor drums 1a to 1d.

[0013] The paper P onto which the toner image is secondarily transferred is stored in a paper cassette 16 arranged at the bottom of the main body of the image forming apparatus 100. The paper P is transported to a nip portion between the secondary transfer roller 9 and the drive roller 11 of the intermediate transfer belt 8 via a paper feed roller 12a and a pair of registration rollers 12b. A sheet made of a dielectric resin is used for the intermediate transfer belt 8, and a seamless belt is usually used.

[0014] In the image forming portion Pd, a belt cleaning device 30 for removing toner and the like remaining on the surface of the intermediate transfer belt 8 is disposed downstream of the secondary transfer roller 9.

[0015] Next, the image forming units Pa to Pd will be described. Around and below the rotatably arranged photoconductor drums 1a to 1d, there are provided charging devices 2a, 2b, 2c, and 2d that charge the photoconductor drums 1a to 1d, an exposure device 5 that exposes image information onto each of the photoconductor drums 1a to 1d, developing devices 3a, 3b, 3c, and 3d that form toner images on the photoconductor drums 1a to 1d, and cleaning devices 7a, 7b, 7c, and 7d that remove developer (toner) remaining on the photoconductor drums 1a to 1d.

[0016] When image data is input from a host device such as a personal computer, first, the surfaces of the photoconductor drums 1a-1d are uniformly charged by the charging devices 2a-2d. Next, the exposure device 5 irradiates light according to the image data, and an electrostatic latent image according to the image data is formed on each of the photoconductor drums 1a-1d. The developing devices 3a-3d are filled with a predetermined amount of two-component developer containing toner of each color, cyan, magenta, yellow, and black.

[0017] When the ratio of toner in the two-component developer filled in each of the developing devices 3a-3d falls below a specified value due to the formation of a toner image described later, toner is supplied from the toner containers 4a-4d to each of the developing devices 3a-3d. The toner in the developer is supplied onto the photoconductor drums 1a-1d by the developing devices 3a-3d and electrostatically adheres to the photoconductor drums 1a-1d. As a result, a toner image is formed according to the electrostatic latent image formed by exposure from the exposure device 5.

[0018] Then, an electric field is applied between the primary transfer rollers 6a-6d and the photoconductor drums 1a-1d by the primary transfer rollers 6a-6d at a predetermined transfer voltage, and the cyan, magenta, yellow, and black toner images on the photoconductor drums 1a-1d are primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship for forming a predetermined full-color image. After that, in preparation for the subsequent formation of a new electrostatic latent image, the toner and the like remaining on the surfaces of the photoconductor drums 1a-1d after the primary transfer are removed by the cleaning devices 7a-7d.

[0019] The intermediate transfer belt 8 is stretched over a driven roller 10 on the upstream side and a driving roller 11 on the downstream side. When the intermediate transfer belt 8 starts to rotate counterclockwise with the rotation of the driving roller 11 by a belt driving motor (not shown), the paper P is transported from the registration roller pair 12b to a nip portion (secondary transfer nip portion) between the driving roller 11 and a secondary transfer roller 9 provided adjacent thereto at a predetermined timing. When the paper P passes through the secondary transfer nip portion, the full-color image on the intermediate transfer belt 8 is secondarily transferred onto the paper P. The paper P to which the toner image has been secondarily transferred is transported to a fixing unit 13.

[0020] The paper P transported to the fixing unit 13 is heated and pressurized by the fixing roller pair 13a, so that the toner image is fixed to the surface of the paper P, and a predetermined full-color image is formed. The paper P on which the full-color image has been formed passes through the transport roller pair 15, has its transport direction diverted by a branching member 21 arranged at a branching portion of the paper transport path 18, and is discharged directly (or after being sent to the double-sided transport path 22 and printed on both sides) by the discharge roller pair 19 onto the discharge tray 20.

[0021] Next, the structure of the intermediate transfer unit 25 and its surroundings will be described. Fig. 2 is a side cross-sectional view showing the structure of the intermediate transfer unit 25. Fig. 3 is a side cross-sectional view showing the structure of the belt cleaning device 30 constituting the intermediate transfer unit 25 and its surroundings.

[0022] The intermediate transfer unit 25 includes primary transfer rollers 6a to 6d, an intermediate transfer belt (belt) 8, a driven roller 10, a drive roller 11, and a belt cleaning device 30. The intermediate transfer belt 8 is rotatably stretched around a plurality of tension rollers. The tension rollers include a drive roller 11 that is disposed at one end (right end) in the arrangement direction of the photosensitive drums 1a to 1d (left and right direction in FIG. 2) and drives the intermediate transfer belt 8 to rotate, a driven roller 10 that is disposed at the other end (left end) in the arrangement direction, and the primary transfer rollers 6a to 6d.

[0023] The belt cleaning device 30 is disposed downstream of the drive roller 11 in the rotation direction of the intermediate transfer belt 8 and upstream of the driven roller 10 in the rotation direction of the intermediate transfer belt 8. The belt cleaning device 30 has a housing 31, a cleaning blade 32, a collection screw 33, a blade holding member 34, a seal member 35, and an opposing roller 40 (see FIG. 3).

[0024] The housing 31 has an opening 31a facing the intermediate transfer belt 8, and a waste toner storage section 31b for storing waste toner scraped off from the surface of the intermediate transfer belt 8.

[0025] The cleaning blade 32 comes into contact with the outer peripheral surface of the intermediate transfer belt 8 and removes residual toner adhering to the intermediate transfer belt 8. For example, a blade made of polyurethane rubber is used as the cleaning blade 32. The blade holding member 34 is made of metal and is attached to the downstream side (left side in FIG. 3) of the opening 31a of the housing 31 in the moving direction (arrow A direction) of the intermediate transfer belt 8.

[0026] The cleaning blade 32 has a base end 32a fixed to a blade holding member 34, and is attached at a predetermined angle with the tip end 32a facing upstream (counter direction) in the moving direction of the intermediate transfer belt 8. The material, hardness, dimensions, amount of penetration and pressure force into the intermediate transfer belt 8, attachment angle, etc. of the cleaning blade 32 are appropriately set according to the specifications of the intermediate transfer belt 8.

[0027] An opposing roller 40 that receives the pressure of the cleaning blade 32 is disposed at a position facing the cleaning blade 32 across the intermediate transfer belt 8. The opposing roller 40 is composed of a core metal 40a, an elastic layer 40b disposed on the outer circumferential surface of the core metal 40a, and a cover layer 40c disposed on the outer circumferential surface of the elastic layer 40b. That is, the opposing roller 40 has the cover layer 40c disposed on the outer circumferential surface. The elastic layer 40b is made of, for example, EPDM (ethylene propylene diene rubber) or the like.

[0028] The cover layer 40c is formed, for example, by covering the outer peripheral surface of the opposing roller 40 (elastic layer 40b) with a tubular high resistance rubber. This allows the cover layer 40c to be easily attached to an existing opposing roller 40, and the increase in the manufacturing cost of the opposing roller 40 can be suppressed. The cover layer 40c may be formed by coating the outer peripheral surface of the opposing roller 40 with a high resistance resin. This allows the cover layer 40c to be easily disposed in a predetermined region of the opposing roller 40 in the axial direction.

[0029] The cover layer 40c is disposed over the entire area of ​​the opposing roller 40 that faces the intermediate transfer belt 8 in the axial direction of the opposing roller 40.

[0030] 3 at the same linear speed as the intermediate transfer belt 8 by the driving force from the same driving source (belt driving motor) as the driving roller 11. The apex (top) of the opposing roller 40 is located slightly above the apex of the driving roller 11 and the apex of the driven roller 10.

[0031] Residual toner removed from the surface of the intermediate transfer belt 8 by the cleaning blade 32 is discharged to the outside of the belt cleaning device 30 as the recovery screw 33 rotates, and is transported to and stored in a toner recovery container (not shown).

[0032] The seal member 35 is a sheet-like member attached to the upstream side (right side in FIG. 3) of the opening 31a of the housing 31 in the rotation direction of the intermediate transfer belt 8. One end (right end in FIG. 3) of the seal member 35 is adhesively fixed to the housing 31, and the other end (left end in FIG. 3) forms a free end. The free end of the seal member 35 contacts the outer circumferential surface of the intermediate transfer belt 8 toward the downstream side in the rotation direction of the intermediate transfer belt 8. The seal member 35 prevents the waste toner in the housing 31 from leaking out from the gap between the housing 31 and the intermediate transfer belt 8. For example, a urethane sheet having a thickness of 100 μm is used as the seal member 35, but a thin plate-like sheet other than a urethane sheet may be used.

[0033] In this embodiment, an elastic layer 40b is provided on the outer circumferential surface of the opposing roller 40. With this configuration, the pressure at the contact portion of the cleaning blade 32 is dispersed, and the stress concentration on the intermediate transfer belt 8 due to foreign matter such as paper powder can be mitigated.

[0034] However, for example, when the image adjustment pattern is transferred to the intermediate transfer belt 8 during toner concentration correction (calibration), a large amount of highly charged toner may accumulate on the cleaning blade 32 at once. Also, when a paper jam occurs, the toner may be transferred to and adhere to the cleaning blade 32 instead of the paper P. At this time, the highly charged toner may cause discharge from the cleaning blade 32 to the opposing roller 40. As the number of discharges increases, leak marks are formed on the intermediate transfer belt 8, and the resistance value of the intermediate transfer belt 8 is likely to decrease. This may result in poor images.

[0035] In particular, in an image forming apparatus 1 that performs high-speed printing or high-quality printing, in order to ensure print quality without reducing productivity, calibration is frequently performed on the non-image forming area of ​​the intermediate transfer belt 8. At this time, the resistance value of the intermediate transfer belt 8 decreases, and the possibility of image defects occurring becomes particularly high.

[0036] In this embodiment, the surface resistance of the cover layer 40c when a voltage of 100 V is applied is 10 to the power of 10 (Ω) or more, and the Asker A hardness of the cover layer 40c is 60° or more and 90° or less. In this embodiment, the Asker A hardness of the cover layer 40c was measured using a rubber hardness meter (Asker Rubber Hardness Meter Type JA, manufactured by Kobunshi Keiki Co., Ltd.) in accordance with a method conforming to JIS K 6301.

[0037] By setting the surface resistance value of the cover layer 40c to 10 to the power of 10 (Ω) or more when a voltage of 100V is applied, discharge from the cleaning blade 32 to the opposing roller 40 can be reduced. In addition, by setting the Asker A hardness of the cover layer 40c to 60° or more and 90° or less, it is possible to prevent damage to the inner circumferential surface of the intermediate transfer belt 8 when foreign matter adheres to the surface of the cover layer 40c. This reduces the formation of leak marks on the intermediate transfer belt 8, thereby suppressing deterioration of the intermediate transfer belt 8. This prevents a decrease in the resistance value of the intermediate transfer belt 8. Therefore, it is possible to reduce deterioration of the intermediate transfer belt 8 while suppressing manufacturing costs without providing a new mechanism, and to prevent the occurrence of image defects.

[0038] Since the cover layer 40c is disposed over the entire area of ​​the opposing roller 40 facing the intermediate transfer belt 8 in the axial direction thereof, discharge from the cleaning blade 32 to the opposing roller 40 can be reduced over the entire area facing the intermediate transfer belt 8.

[0039] In this embodiment, the cover layer 40c is disposed over the entire area facing the intermediate transfer belt 8 in the axial direction of the opposing roller 40, but the cover layer 40c may be disposed only in an area facing an image formable area of ​​the intermediate transfer belt 8 in the axial direction of the opposing roller 40. Furthermore, the cover layer 40c may be disposed only in an area facing an area where an image adjustment pattern for calibration is formed on the intermediate transfer belt 8 in the axial direction of the opposing roller 40. This makes it possible to reduce the formation area of ​​the cover layer 40c while suppressing a decrease in the resistance value of the intermediate transfer belt 8, thereby further suppressing an increase in the manufacturing cost of the opposing roller 40.

[0040] The cover layer 40c is preferably changed depending on the material of the intermediate transfer belt 8 in order to adjust the surface resistance value. In this embodiment, the cover layer 40c has the same triboelectric series as the inner circumferential surface of the intermediate transfer belt 8. As a result, the cover layer 40c is unlikely to be triboelectrically charged when it slides against the inner circumferential surface of the intermediate transfer belt 8, and charge is unlikely to accumulate. Therefore, discharge from the cleaning blade 32 to the opposing roller 40 can be further reduced.

[0041] For example, when the intermediate transfer belt 8 is made of polyimide, the cover layer 40c is preferably made of a material having a triboelectric series close to that of polyimide. Also, when the intermediate transfer belt 8 is made of polyamide, the cover layer 40c is preferably made of a material having a triboelectric series close to that of polyamide.

[0042] Next, the effects of the present invention will be specifically described using examples and comparative examples. In the following experiments, the relationship between the number of times calibration is performed and the occurrence of image defects was evaluated.

[0043] Specifically, the relationship between the cumulative number of times the image adjustment pattern (half density toner image) transferred to the intermediate transfer belt 8 is printed and the density unevenness (ΔID) of the image adjustment pattern transferred to the intermediate transfer belt 8 is measured, and the results are shown in Fig. 4. The density unevenness (ΔID) is calculated from the density difference between both ends of the half image in the axial direction by measuring the density of the image adjustment pattern transferred to the intermediate transfer belt 8 with an image density sensor (not shown).

[0044] In addition, when the cumulative number of printed sheets reached 50k, the surface roughness (μm) of the outer peripheral surface (surface that contacts the cleaning blade 32) and the inner peripheral surface (surface that contacts the opposing roller 40) of the intermediate transfer belt 8 in Comparative Example 1 was measured in the longitudinal direction (axial direction), and the results are shown in Figure 5.

[0045] The opposing roller 40 according to Example 1 is formed with a cover layer 40c, which is made of polyimide and is formed by covering the outer circumferential surface of the opposing roller 40 with a tubular high resistance rubber. The surface resistance value of the cover layer 40c is 10 to the power of 10 (Ω) or more and 10 to the power of 15 (Ω) or less, and the Asker A hardness of the cover layer 4cb is 80°. The intermediate transfer belt 8 according to Example 1 and Comparative Example 1 is made of polyimide. The opposing roller according to Comparative Example 1 is not formed with the cover layer 40c.

[0046] 4, even when the cumulative number of times the image adjustment pattern is printed exceeds 1000 times, the density unevenness (ΔID) of the image adjustment pattern transferred to the intermediate transfer belt 8 of Example 1 is suppressed compared to the density unevenness (ΔID) of the image adjustment pattern transferred to the intermediate transfer belt 8 of Comparative Example 1. It was found that by providing a cover layer 40c having a surface resistance value of 10 to the power of 10 (Ω) or more and an Asker A hardness of 60° to 90°, it is possible to reduce deterioration of the intermediate transfer belt 8 and prevent the occurrence of image defects.

[0047] 5, the surface roughness (μm) of the inner peripheral surface of the intermediate transfer belt 8 in Comparative Example 1 is greater than the surface roughness (μm) of the outer peripheral surface of the intermediate transfer belt 8 in Comparative Example 1. This indicates that it is necessary to place a cover layer 40c on the inner peripheral surface side of the intermediate transfer belt 8 to reduce deterioration of the intermediate transfer belt 8.

[0048] Next, an evaluation was performed as to whether or not deterioration of the intermediate transfer belt 8 can be reduced when a cover layer 40c having a surface resistance value of 10 to the power of 10 (Ω) or more is provided. Specifically, as shown in Fig. 6, a high resistance sheet 400 constituting the cover layer 40c was placed between a belt 800 constituting the intermediate transfer belt 8 and a conductive plate 500. In addition, a voltage was applied between a metal member 500 placed on the upper surface of the belt 800 and the conductive plate 500 while changing the voltage to 10 V, 100 V, and 250 V, and the surface resistance value of the belt 800 was measured.

[0049] In addition, without placing the high resistance sheet 400 between the belt 800 and the conductive plate 500, a voltage of 10 V, 100 V, or 250 V was applied between the metal member 500 and the conductive plate 500, and the surface resistance value of the belt 800 was measured and is summarized in Table 1.

[0050] [Table 1]

[0051] When a high resistance sheet 400 having a surface resistance of 10 to the power of 10 (Ω) or more and an Asker A hardness of 60° to 90° or less was provided, no leak marks were observed on the belt 800. This shows that by providing a cover layer 40c having a surface resistance of 10 to the power of 10 (Ω) or more and an Asker A hardness of 60° to 90° or less, it is possible to reduce deterioration of the intermediate transfer belt 8 and prevent the occurrence of image defects.

[0052] Next, an evaluation was performed as to whether or not the stress concentration on the intermediate transfer belt 8 due to foreign matter can be alleviated when a cover layer 40c with an Asker A hardness of 70° is provided. Specifically, a foreign matter with an outer diameter of 30 μm was placed at the contact portion between the outer circumferential surface of the intermediate transfer belt 8 and the cleaning blade 32, and the amount of deformation of the intermediate transfer belt 8 toward the opposing roller 40 (diametrically inward) at the contact portion was measured, and the results are shown in Table 2. Here, toner aggregated within a rotating unit was used as the foreign matter.

[0053] The opposing roller 40 according to Example 2 is formed with a cover layer 40c, which is made of polyimide and is formed by covering the outer circumferential surface of the opposing roller 40 with a tube-shaped high resistance rubber. The surface resistance value of the cover layer 40c is 10 to the power of 10 (Ω) or more and 10 to the power of 11 (Ω) or less, and the Asker A hardness of the cover layer 4cb is 80°. The intermediate transfer belt 8 according to Example 2 and Comparative Example 2 is made of polyimide. The opposing roller according to Comparative Example 2 is not provided with the cover layer 40c and the elastic layer 40b, and is made of a core metal 40a made of aluminum.

[0054] [Table 2]

[0055] As shown in Table 2, the amount of deformation of the intermediate transfer belt 8 according to Example 2 is smaller than the amount of deformation of the intermediate transfer belt 8 according to Comparative Example 2. This shows that by providing the cover layer 40c with an Asker A hardness of 70°, the pressure at the contact portion of the cleaning blade 32 is dispersed, and the stress concentration on the intermediate transfer belt 8 due to foreign matter such as paper powder can be mitigated. In addition, it was confirmed that the inner peripheral surface of the intermediate transfer belt 8 disposed opposite the opposing roller according to Comparative Example 2 had a plurality of minute holes formed thereon and was scratched.

[0056] In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications are possible within the scope of the present invention. In the above-mentioned embodiments, the belt cleaning device 30 for cleaning the intermediate transfer belt 8 used in the intermediate transfer type image forming apparatus 100 has been described, but the belt cleaning device can also be used as a belt cleaning device for cleaning the transfer transport belt in a direct transfer type image forming apparatus equipped with a transfer transport belt for sequentially transporting the paper P to each image forming unit Pa to Pb instead of the intermediate transfer belt 8.

[0057] Furthermore, the present invention is not limited to the color printer as shown in FIG. 1, but can be applied to various image forming apparatuses equipped with a belt cleaning device, such as digital multifunction machines, color copiers, and facsimiles.

[0058] In the present embodiment, the opposing roller 40 is composed of the core metal 40a, the elastic layer 40b, and the cover layer 40c, but the present invention is not limited to this. For example, the cover layer 40c may be composed of the same material as the elastic layer 40b, and the cover layer 40c and the elastic layer 40b may be integrated together. [Industrial Applicability]

[0059] The present invention can be used in a belt driving device equipped with a belt cleaning device having a cleaning blade that removes residual toner adhering to an endless belt and an opposing roller that is arranged opposite the cleaning blade, and an image forming apparatus equipped with the same. [Explanation of symbols]

[0060] 1. Image forming device 1a~1d Photoconductor drum 2a~2d Charging device 3a~3d developing device 4a~4d Toner container 4cb cover layer 5 Exposure equipment 6a~6d Primary transfer roller 7a~7d Cleaning device 8 Intermediate transfer belt (belt) 9 Secondary transfer roller 10 Driven roller 11 Drive roller 12a Paper feed roller 12b Registration roller pair 13 Fixing section 13a Fixing roller pair 15 Transport roller pair 16 Paper Cassette 18 Paper transport path 19 Discharge Roller Pair 20 Output Tray 21 Branching member 22-sided conveyor 25 Intermediate transfer unit 30 Belt cleaning device 31 Housing 31a opening 31b Waste toner storage section 32 Cleaning blade 32a Tip 32a Proximal end 33 Recovery screw 34 Blade holding member 35 Sealing material 40 Cover Layer 40 Opposing Roller 40a core wire 40b Elastic layer 40c cover layer 100 Image forming device 400 High resistance sheet 500 Metallic parts 500 Conductive plate 800 Belt A Arrow P paper Pa~Pd Image forming section

Claims

1. An endless belt; A plurality of tension rollers that rotatably tension the belt; a belt cleaning device including a cleaning blade that contacts an outer circumferential surface of the belt to remove foreign matter adhering to the belt, and an opposing roller that is disposed opposite the cleaning blade across the belt and contacts an inner circumferential surface of the belt; In a belt drive device comprising: the opposing roller has a cover layer disposed on an outer peripheral surface thereof, the cover layer having a surface resistance of 10 to the power of 10 (Ω) or more when a voltage of 100 V is applied thereto, and an Asker A hardness of the cover layer is 60° or more and 90° or less.

2. 2. The belt drive device according to claim 1, wherein the cover layer is disposed over the entire area of ​​the opposing roller facing the belt in the axial direction.

3. 3. The belt driving device according to claim 1, wherein the cover layer is formed by covering an outer circumferential surface of the opposing roller with a tubular high resistance rubber.

4. 3. The belt driving device according to claim 1, wherein the cover layer is formed by covering the outer circumferential surface of the opposing roller with a highly resistive resin.

5. 3. The belt driving device according to claim 1, wherein the cover layer has a triboelectric series identical to that of the inner peripheral surface of the belt.

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

7. 6. The image forming apparatus according to claim 5, wherein the cover layer is disposed only in an area of ​​the belt facing an image forming area in an axial direction of the facing roller.

8. 6. The image forming apparatus according to claim 5, wherein the cover layer is disposed only in an area facing an area in the axial direction of the opposing roller, the area facing an image adjustment pattern for calibration formed on the belt.

Images