Intermediate transfer unit and image forming apparatus

Abstract

To provide an intermediate transfer unit and an image forming apparatus that allow the intermediate transfer unit to be easily pulled out from an apparatus body while suppressing deformation of the intermediate transfer unit, and that can prevent a user from inadvertently touching instruments or the like supported by a housing of the intermediate transfer unit.SOLUTION: An intermediate transfer unit includes an intermediate transfer belt and a housing that supports at least a tension roller that stretches the intermediate transfer belt and is provided in a manner of being pulled-out from the main body of the image forming apparatus. A handle 124 serving as a gripping section to be gripped by a worker when pulling out the intermediate transfer unit is provided on a downstream side face plate of the housing orthogonal to the pull-out direction on the downstream side in the pull-out direction of the intermediate transfer unit. Additionally, the downstream side face plate is covered by an inner cover 90 serving as a cover member. The inner cover 90 has a hole part 91a that allows the worker to access the handle 124.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an intermediate transfer unit and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known an intermediate transfer unit that includes an intermediate transfer belt and a housing that supports at least a tension roller around which the intermediate transfer belt is tensioned, and that is provided so as to be removable from a main body of an image forming apparatus.

[0003] Patent document 1 describes an intermediate transfer unit in which a handle, which serves as a gripping part that an operator grasps when pulling out the intermediate transfer unit, is provided on the front panel, which serves as a downstream side panel that is perpendicular to the pulling-out direction and downstream of the pulling-out direction of the frame that serves as the housing. Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, when a user accesses jammed paper through the opening in the image forming device body through which the intermediate transfer unit is pulled out to clear the jam, there was a risk that the user might inadvertently come into contact with equipment supported by the housing of the intermediate transfer unit. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides an intermediate transfer unit that includes an intermediate transfer belt and a housing that supports at least a tension roller that tensions the intermediate transfer belt, and is arranged to be able to be pulled out from the main body of an image forming device, wherein a gripping portion that an operator grasps when pulling out the intermediate transfer unit is provided on a downstream side panel of the housing, downstream in the pulling-out direction and perpendicular to the pulling-out direction, and has a cover member that covers the downstream side panel, and the cover member has a hole portion through which the operator can access the gripping portion. Effect of the Invention

[0006] According to the present invention, the intermediate transfer unit can be easily pulled out from the main body of the apparatus while preventing deformation of the intermediate transfer unit, and the user can be prevented from inadvertently touching equipment, etc. supported by the housing of the intermediate transfer unit. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a front view of the exterior of the printer with the pair of front doors open. [Figure 4] 1A is an enlarged front view of the area around the transfer door when the transfer door is closed, and FIG. 1B is an enlarged front view of the area around the transfer door when the transfer door is open. [Diagram 5] FIG. 4 is a perspective view of a tension applying mechanism attached to the intermediate transfer unit, as viewed from below. [Figure 6] FIG. 2 is a schematic perspective view of an intermediate transfer unit pulled out from the main body of the apparatus. [Figure 7] FIG. 4 is a schematic perspective view of the intermediate transfer unit with the inner cover removed. [Figure 8] FIG. 4A is a front view of the intermediate transfer unit with the inner cover attached, and FIG. 4B is a front view of the intermediate transfer unit with the inner cover removed. [Figure 9] FIG. 4 is a diagram illustrating a state in which the intermediate transfer belt is removed from the intermediate transfer unit. [Figure 10] Cross-sectional view taken along line B-B in Figure 8(a). [Figure 11] Cross-sectional view taken along line AA in Figure 8(a). [Figure 12] FIG. [Figure 13] 5A and 5B are diagrams illustrating a state of the intermediate transfer belt before and after the tension applying mechanism is removed. [Figure 14] FIG. 4 is a diagram showing a state in which an inner cover and a front panel are removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The best mode for carrying out the present invention will be described below with reference to the drawings. Note that a person skilled in the art can easily modify and alter the present invention within the scope of the claims to create other embodiments, and these modifications and alterations are included in the scope of the claims. The following description is an example of the best mode for carrying out the present invention, and does not limit the scope of the claims.

[0009] A so-called tandem type intermediate transfer printer (hereinafter simply referred to as printer) will be described below as an embodiment of an image forming apparatus to which the present invention is applied. First, the basic configuration of this printer will be described. FIG. 1 is a schematic diagram of a printer 60 according to this embodiment. This printer 60 has four process units 6Y, M, C, and K for generating toner images of yellow (Y), magenta (M), cyan (C), and black (K).

[0010] The four process units 6Y, M, C, K each have a drum-shaped photoconductor 1Y, M, C, K. Around the photoconductor 1Y, M, C, K are charging devices 2Y, M, C, K, developing devices 5Y, C, M, K, drum cleaning devices 4Y, M, C, K, and static eliminators. The process units 6Y, M, C, K each use a different color Y, M, C, K toner, but otherwise have the same configuration.

[0011] An optical writing unit 20 is disposed above the process units 6Y, M, C, and K for irradiating the surfaces of the photoconductors 1Y, M, C, and K with laser light L to write electrostatic latent images. An intermediate transfer unit 7 is disposed below the process units 6Y, M, C, and K as a pull-out unit having an endless intermediate transfer belt 8 as a belt member. In addition to the intermediate transfer belt 8, the intermediate transfer unit 7 has a plurality of tension rollers disposed inside the loop of the intermediate transfer belt, a tension roller 16, a belt cleaning device 100, a lubricant application device 200, and the like.

[0012] Arranged inside the loop of the intermediate transfer belt 8 are four primary transfer rollers 9Y, M, C, and K, a driven roller 10, a drive roller 11, a secondary transfer opposing roller 12, three cleaning opposing rollers 13, 14, and 15, and an application brush opposing roller 17. Each of these rollers functions as a tension roller that tensions the intermediate transfer belt 8 by wrapping the intermediate transfer belt 8 around a portion of its circumferential surface.

[0013] Incidentally, the cleaning facing rollers 13, 14, and 15 do not necessarily have to have a function of applying a constant tension, and may be ones that rotate following the rotation of the intermediate transfer belt 8. The intermediate transfer belt 8 is caused to move endlessly in the clockwise direction in the figure by the rotation of the drive roller 11 that is driven to rotate clockwise in the figure by a drive means.

[0014] Four primary transfer rollers 9Y, M, C, K arranged inside the belt loop sandwich the intermediate transfer belt 8 between them and the photoconductors 1Y, M, C, K. This forms primary transfer nips for Y, M, C, K where the front surface of the intermediate transfer belt 8 comes into contact with the photoconductors 1Y, M, C, K. A primary transfer bias of the opposite polarity to the toner is applied to each of the primary transfer rollers 9Y, M, C, K by a power source.

[0015] In addition, the secondary transfer opposing roller 12 disposed inside the belt loop sandwiches the intermediate transfer belt 8 between itself and the secondary transfer roller 18 disposed outside the belt loop. This forms a secondary transfer nip where the front surface of the intermediate transfer belt 8 and the secondary transfer roller 18 come into contact with each other.

[0016] A secondary transfer bias having a polarity opposite to that of the toner is applied by a power source to the secondary transfer roller 18. Alternatively, a paper transport belt may be stretched across the secondary transfer roller, several support rollers, and a drive roller, and the intermediate transfer belt 8 and the paper transport belt may be sandwiched between the secondary transfer roller 18 and the secondary transfer opposing roller 12.

[0017] The belt cleaning device 100 disposed outside the belt loop includes a pre-cleaning unit 100a for roughly removing untransferred toner images on the intermediate transfer belt 8. It also includes a normally charged toner cleaning unit 100b for removing toner charged to the normally charged polarity on the intermediate transfer belt 8. It also includes an oppositely charged toner cleaning unit 100c for removing toner charged to the opposite polarity (positive polarity) to the normally charged polarity (negative polarity) on the intermediate transfer belt 8. The arrangement order of the above cleaning units 100a, 100b, and 100c is merely an example, and they may be arranged in the order of the pre-cleaning unit, the oppositely charged toner cleaning unit, and the normally charged toner cleaning unit.

[0018] Each of the cleaning units 100a, 100b, and 100c has a cleaning brush roller 101, a collection roller 102, and a scraping blade 103. The collection roller 102 collects toner adhering to the cleaning brush roller 101, and the scraping blade 103 comes into contact with the collection roller 102 to scrape off the toner from the roller surface.

[0019] A voltage of the opposite polarity (positive polarity) to the toner normally charged polarity (negative polarity) is applied to the pre-cleaning unit 100a and the cleaning brush roller 101 of the normally charged toner cleaning unit 100b, and the toner of the normally charged polarity on the intermediate transfer belt 8 is electrostatically removed. A voltage of a positive polarity larger than that of the cleaning brush roller 101 is applied to the collection roller 102 of the pre-cleaning unit 100a and the normally charged toner cleaning unit 100b, and the toner of the normally charged polarity attached to the cleaning brush roller 101 is electrostatically collected.

[0020] A voltage of normal toner charge polarity (negative polarity) is applied to the cleaning brush roller 101 of the oppositely charged toner cleaning unit 100c, and the toner of opposite charge polarity on the intermediate transfer belt 8 is electrostatically removed. A voltage of negative polarity larger than that of the cleaning brush roller 101 is applied to the collection roller 102 of the oppositely charged toner cleaning unit 100c, and the toner of opposite charge polarity attached to the cleaning brush roller 101 is electrostatically collected.

[0021] Three cleaning opposing rollers 13, 14, and 15 arranged inside the belt loop sandwich the intermediate transfer belt 8 between themselves and the cleaning brush rollers 101 of each cleaning section. This forms a cleaning nip where the front surface of the intermediate transfer belt 8 comes into contact with the cleaning brush rollers 101 of each cleaning section.

[0022] To protect the surface of the intermediate transfer belt 8, a lubricant is applied to the surface of the intermediate transfer belt 8 by a lubricant application device 200. The lubricant application device 200 includes a solid lubricant 202 such as a lump of zinc stearate, and an application brush roller 201 as an application member that contacts the solid lubricant 202 and applies the lubricant powder obtained by scraping it off from the solid lubricant 202 by rotation to the surface of the intermediate transfer belt 8.

[0023] The printer 60 of this embodiment includes a paper feed section 30 having a paper feed cassette 31 that stores recording paper P as a recording material, and a paper feed roller 32 that feeds the recording paper P from the paper feed cassette 31 to a paper feed path. Also, a pair of registration rollers 33 that receives the recording paper P sent from the paper feed section 30 and sends it toward the secondary transfer nip at a predetermined timing is provided on the right side of the above-mentioned secondary transfer nip in the drawing.

[0024] In addition, a fixing device 40 having a heating roller 41 and a pressure roller 42 that receives the recording paper P sent out from the secondary transfer nip and fixes the toner image onto the recording paper P is provided to the left of the secondary transfer nip described above in the figure.

[0025] A bottle storage section 50 is disposed in the upper right corner of the optical writing unit 20 in the figure. The bottle storage section 50 stores toner bottles 51Y, 51M, 51C, and 51K that contain toner for replenishing the toner to the developing devices 5Y, 51M, 51C, and 51K as necessary.

[0026] When image information is sent from a personal computer or the like, this printer rotates the drive roller 11 to move the intermediate transfer belt 8. The tension rollers other than the drive roller 11 are rotated following the belt. At the same time, the photoconductors 1Y, M, C, K of the process units 6Y, M, C, K are rotated. In addition, the surfaces of the photoconductors 1Y, M, C, K are uniformly charged by the charging devices 2Y, M, C, K, and an electrostatic latent image is formed on the charged surfaces by irradiating them with laser light L by the optical writing unit 20.

[0027] Then, the electrostatic latent images formed on the surfaces of the photoconductors 1Y, M, C, K are developed by the developing devices 5Y, M, C, K toner images are obtained on the photoconductors 1Y, M, C, K. The Y, M, C, K toner images are primarily transferred and superimposed on the front surface of the intermediate transfer belt 8 at the primary transfer nips for Y, M, C, K described above. As a result, a four-color superimposed toner image is formed on the front surface of the intermediate transfer belt 8.

[0028] Meanwhile, in the paper feed section 30, a paper feed roller 32 feeds out recording paper P one sheet at a time from a paper feed cassette 31 and transports it to a pair of registration rollers 33. Then, at a timing that can be synchronized with the four-color superimposed toner image on the intermediate transfer belt 8, the pair of registration rollers 33 is driven to feed the recording paper P into the secondary transfer nip, and the four-color superimposed toner image on the belt is transferred collectively (secondarily) onto the recording paper P. In this way, a full-color image is formed on the surface of the recording paper P. After the full-color image has been formed on the recording paper P, it is transported from the secondary transfer nip to a fixing device 40, where the toner image is fixed.

[0029] After the Y, M, C, and K toner images have been primarily transferred to the intermediate transfer belt 8, the photoconductors 1Y, M, C, and K are cleaned of residual toner by drum cleaning devices 4Y, M, C, and K. After that, the photoconductors are neutralized by a neutralization lamp and then uniformly charged by charging devices 2Y, M, C, and K in preparation for the next image formation. In addition, after the intermediate transfer belt 8 has been primarily transferred to the recording paper P, the belt cleaning device 100 cleans the residual toner from the intermediate transfer belt 8.

[0030] FIG. 2 is a front view of the appearance of the printer 60. As shown in FIG. 2, a pair of front doors 61a, 61b are provided on the front of the printer 60 as opening / closing covers for opening / closing an opening 60a of the printer body (hereinafter referred to as the device body). The front door 61a on the right side in the figure is rotatably attached to the right end of the device body by a hinge, and the front door 61b on the left side in the figure is rotatably attached to the right end of the device body by a hinge, so that the opening 60a of the device body is opened and closed in a double door manner.

[0031] FIG. 3 is an external front view of the printer 60 with the pair of front doors 61a, 61b open. 3, opening the pair of front doors 61a, 61b exposes the process units 6Y, M, C, K, the intermediate transfer unit 7, the fixing device 40, the paper transport section 62, and the paper discharge section 63. The paper transport section 62 transports the recording paper P sent from the paper feed section 30 toward the secondary transfer roller 18, and the paper discharge section 63 transports the recording paper that has passed through the fixing device 40 and discharges it outside the printer 60.

[0032] Each process unit 6Y, M, C, K is provided with a locking mechanism 21Y, M, C, K that locks the process unit to the apparatus body, and by releasing the lock with the locking mechanism, the process unit can be attached and detached from the front side of the apparatus. Each process unit 6Y, M, C, K may be configured to be removable from the apparatus body, and components of the process unit (photoconductor 1, charging device 2, developing device 5, drum cleaning device 4, etc.) may be replaced with the process unit removed.

[0033] The fixing device 40 also includes a locking mechanism 43 that locks the fixing device 40 to the device body, and can be attached and detached from the front side of the device by releasing the locking mechanism 43. The fixing device 40 may be configured to be placed on the paper discharge section 63, and the fixing device 40 may be attached and detached by pulling the paper discharge section 63 out of the device body and lifting the fixing device 40.

[0034] The paper transport section 62 and the paper discharge section 63 are provided so as to be removable from the device body. When a paper jam occurs, the jammed paper can be removed by releasing the locking mechanism 62a, 63b from the device body and removing the paper from the device body.

[0035] Further, the intermediate transfer unit 7 is provided with a small transfer door 70 which is an opening and closing member. Figure 4(a) is an enlarged front view of the area around the transfer door 70 when the transfer door 70 is closed, and Figure 4(b) is an enlarged front view of the area around the transfer door 70 when the transfer door 70 is open. The small transfer door 70 is provided with a locking member 75 that locks the small transfer door 70 in the closed position shown in Fig. 4(a). The locking member 75 is attached to the small transfer door 70 so as to be movable within a predetermined range in the vertical direction, and is biased vertically upward by a biasing member such as a spring. The locking member 75 has an operation portion 75b recessed inwardly to allow an operator to operate the locking member 75, and the operation portion 75b is exposed from the opening 70a of the small transfer door 70.

[0036] When opening the small transfer door 70, a finger is inserted into the operating portion 75b of the locking member 75 through the opening 70a of the small transfer door 70, and the locking member 75 is pushed downward against the biasing force of the spring. This causes the locking member 75 to move downward, releasing the lock, and the small transfer door 70 can be moved to the open position as shown in FIG. 4(b).

[0037] When the small transfer door 70 is opened, the upper part of the belt cleaning device 100, the lubricant application device 200, and the tension applying mechanism 160 that supports the tension roller 16, which were covered by the small transfer door 70, are exposed. Note that reference numeral 82 shown in Fig. 4 denotes a front frame 82 of the intermediate transfer unit 7, and reference numeral 90 denotes an inner cover as a cover member that covers the front frame 82 etc.

[0038] The intermediate transfer unit 7 has a cleaning lock lever 190 for locking the belt cleaning device 100 to the intermediate transfer unit 7. The lock is released by rotating the cleaning lock lever 190 counterclockwise by 90 degrees from the state shown in FIG. 4B. This allows the belt cleaning device 100 to be removed from the intermediate transfer unit 7. Furthermore, by rotating the lock lever 190 counterclockwise by 90 degrees from the state shown in FIG. 4B, the cleaning opposing rollers 13, 14, and 15 are separated from the corresponding cleaning brush rollers, and the intermediate transfer belt 8 is separated from the three cleaning brush rollers of the belt cleaning device 100. This allows the belt cleaning device 100 to be removed from the intermediate transfer unit 7 without damaging the surface of the intermediate transfer belt 8.

[0039] The lubricant application device 200 has a lubricant lock lever 203 for locking the lubricant application device 200 to the intermediate transfer unit 7. By rotating this lubricant lock lever 203 counterclockwise by 90° from the state shown in FIG. 4(b), the lock is released and the lubricant application device 200 can be removed from the intermediate transfer unit 7.

[0040] The tension applying mechanism 160 is positioned by positioning pins 82 a and 82 b provided on the front frame 82 of the intermediate transfer unit, and is screwed to the intermediate transfer unit 7 by screws 169 .

[0041] FIG. 5 is a perspective view of the tension applying mechanism 160 attached to the intermediate transfer unit 7, as viewed from below. The tension applying mechanism 160 mainly comprises a roller holder that rotatably supports the tension roller 16, a base member 161 that holds the roller holder so that it can swing or slide, and a pressure applying mechanism that applies pressure to the roller holder to press the tension roller 16 supported by the roller holder against the intermediate transfer belt.

[0042] The base member 161 is made of sheet metal, and its end on the front side of the device is bent 90° upward to form a positioning surface portion 162. This positioning surface portion 162 is provided with positioning holes 162a, 162b into which positioning pins 82a, 82b provided on the front frame 82 of the intermediate transfer unit 7 are inserted. The positioning surface portion 162 is also provided with a screw through hole 162c through which a screw 169 for screwing the tension applying mechanism 160 to the front frame 82 passes.

[0043] The base member 161 also has a guide portion 165 that guides movement (movement in the front-rear direction of the device) when the lubricant application device 200 is attached to the intermediate transfer unit 7. Also, a holder holding plate 163 that holds the front end of the roller holder is provided on the rear side of the device (inside the device) of the positioning surface portion 162. When the tension applying mechanism 160 is attached to the intermediate transfer unit 7, a predetermined gap is formed between the holder holding plate 163 and the front frame 82.

[0044] When removing the tension applying mechanism 160 from the intermediate transfer unit 7, first, the belt cleaning device 100 and the lubricant application device 200 are removed, and the intermediate transfer unit 7 is pulled out from the device body. Next, the screw 169 is removed to release the fastening of the tension applying mechanism 160. Next, the tension applying mechanism 160 is moved forward to remove the positioning pins 82a, 82b from the positioning holes 162a, 162b. As described above, a predetermined gap is formed between the holder holding plate 163 and the front frame 82, so that the tension applying mechanism 160 can move forward by this gap. This allows the positioning pins 82a, 82b to be removed from the positioning holes 162a, 162b. Finally, the tension applying mechanism 160 can be removed from the intermediate transfer unit 7 by moving the tension applying mechanism 160 downward.

[0045] Fig. 6 is a schematic perspective view of the intermediate transfer unit 7 when it is pulled out from the main body of the apparatus, and Fig. 7 is a schematic perspective view of the intermediate transfer unit with the inner cover 90, which is a cover member, removed. Fig. 8 is a front view of the intermediate transfer unit 7, where (a) is a front view of the intermediate transfer unit 7 with the inner cover 90 attached, and (b) is a front view of the intermediate transfer unit with the inner cover 90 removed.

[0046] The intermediate transfer unit 7 has a frame housing 80 that supports a plurality of tension rollers disposed inside the loop of the intermediate transfer belt 8, a tension applying mechanism 160, a belt cleaning device 100, a lubricant application device 200, and the like. The frame housing 80 is supported on slide rails 81 provided on the main body of the apparatus so as to be slidable in the front-rear direction of the apparatus.

[0047] 7, frame housing 80 has a front frame 82 made of sheet metal and perpendicular to the front-rear direction of the device (which is also the direction in which intermediate transfer unit 7 is pulled out), and a rear frame 83 made of sheet metal and perpendicular to the front-rear direction of the device. Furthermore, horizontal frames 85 are disposed on both ends of frame housing 80 in the left-right direction of the device.

[0048] FIG. 9 shows a state in which the intermediate transfer belt is removed from the intermediate transfer unit 7. 9, the frame housing 80 has a plurality of stay members 84. One end of each of the stay members 84 is fixed to the front frame 82, and the other end is fixed to the rear frame 83.

[0049] The frame housing 80 also has a handle 124 as a gripping portion, and a pair of front plates 120a, 120b made of sheet metal. Of the two front plates 120a, 120b, one front plate 120a is screwed to the right end of the front frame 82 with a screw 129 (see FIG. 8), and the other front plate 120b is screwed to the left end of the front frame 82 with a screw 129. In this embodiment, the front frame 82 and the pair of front plates form the downstream side plate of the housing.

[0050] One of the front plates 120a is formed with a circular positioning hole 122 which serves as a primary reference for positioning the intermediate transfer unit 7 relative to the device body. The other front plate 120b is formed with a slotted positioning hole 123 which is elongated in the left-right direction of the device and serves as a secondary reference for positioning the intermediate transfer unit 7 relative to the device body.

[0051] As described below, screws 125 (see FIG. 14) are inserted into these positioning holes 122, 123, and the intermediate transfer unit 7 is positioned and fastened to the device body by screwing the screws 125 into screw holes 66a provided in the front side plate 66 of the device body shown in FIG. 6.

[0052] The intermediate transfer unit 7 is fixed to the main body of the apparatus with screws, so that the intermediate transfer unit 7 cannot be easily pulled out from the main body of the apparatus. This prevents the intermediate transfer unit 7 from being pulled out during maintenance or other work performed by a serviceman.

[0053] As described above, the frame housing 80 supports many functional devices of the intermediate transfer unit, such as the multiple tension rollers disposed inside the loop of the intermediate transfer belt 8, the tensioning mechanism 160, the belt cleaning device 100, and the lubricant application device 200. In this way, the frame housing 80 supports many functional devices, and thus the load on the frame housing 80 becomes large. However, due to the structure of the frame housing 80 and the pair of front panels 120a, 120b fastened to the front frame 82 being positioned and fastened to the device main body, the frame housing 80 can firmly support these functional devices without being deformed, even if the load on the frame housing 80 is large.

[0054] A drive motor 180a for driving a separation mechanism for moving the Y, M, and C primary transfer rollers 9Y, 9M, and 9C toward and away from the photoconductor is attached to the front frame 82. A drive motor 180b for driving a separation mechanism for moving the K primary transfer roller 9K toward and away from the photoconductor is also attached to the front frame 82. A cable 181 for supplying power and the like to the drive motors 180a and 180b is laid around the front frame 82.

[0055] 6, a resin inner cover 90 is attached to the frame housing 80 as a cover member that covers the front panels 120a, 120b and the front frame 82. As a result, the drive motors 180a, 180b and the cable 181 attached to the front frame 82 are covered by the inner cover 90.

[0056] As described above, when a paper jam occurs, the pair of front doors 61a, 61b are opened, and then the paper transport section 62 and the paper discharge section 63 are pulled out to clear the jam. If the inner cover 90 does not cover the electrical components such as the drive motors 180a, 180b and the cable 181, there is a risk of accidentally touching these electrical components. As a result, for example, the cable may come off the drive motor, or the electrical components attached to the front frame 82 may be damaged. In addition, the front panels 120a, 120b and the front frame 82 are made of sheet metal, and if the user accidentally touches these sharp parts, there is a risk of injury.

[0057] Meanwhile, as shown in this embodiment, by covering the front panels 120a, 120b and the front frame 82 with the inner cover 90, it is possible to prevent the user from accidentally touching the drive motor and cables held by the front frame 82. It is also possible to prevent the user from accidentally touching dangerous points such as sharp parts of the front panels 120a, 120b and the front frame 82. Furthermore, by covering the front panels 120a, 120b and the front frame 82 with the inner cover 90, it is possible to improve the appearance when the front doors 61a, 61b are opened.

[0058] As shown in FIGS. 6 and 8A, the inner cover 90 has screw guide holes 92 at both left and right ends thereof for guiding the screws 125 for screwing the intermediate transfer unit 7 to the apparatus body. FIG. 10 is a cross-sectional view taken along line BB of FIG. As shown in FIG. 10, the screw guide hole 92 is provided so as to communicate with the positioning hole 122 of the front plate 120. When the intermediate transfer unit 7 is pulled out from the apparatus body, a screwdriver is inserted into the screw guide hole 92 to access the screw 125 screwed into the screw hole 66a of the front side plate 66, and the screw 125 is removed from the screw hole 66a. At this time, the screw 125 may come off the screwdriver and fall. However, even if the screw 125 falls from the screwdriver, the screw guide hole 92 can catch the screw 125, and the screw 125 can be prevented from falling into the apparatus body. In other words, the screw guide hole 92 functions as a fall prevention portion.

[0059] The inner cover 90 is made of resin and has low rigidity. Therefore, if a handle for pulling out the intermediate transfer unit 7 is provided on the inner cover 90, the following problem occurs. That is, as described above, the intermediate transfer unit 7 is heavy because it includes many functional devices of the intermediate transfer unit, such as the tension applying mechanism 160, the belt cleaning device 100, and the lubricant application device 200. Therefore, when pulling out the heavy intermediate transfer unit 7 by gripping the handle provided on the inner cover 90, the inner cover 90 may be deformed.

[0060] On the other hand, by providing handles on the front panels 120a, 120b of the frame housing 80, which is made of sheet metal and has high rigidity, as in this embodiment, the intermediate transfer unit 7 can be pulled out without deforming the front panels 120a, 120b. Also, as described above, the frame housing 80 is reinforced in the front-rear direction of the device by a plurality of stay members 84 (see FIG. 9). Therefore, when the intermediate transfer unit 7 is pulled out, the frame housing 80 will not deform. Note that the handle may be provided on the front frame 82 of the frame housing 80.

[0061] Since the inner cover 90 covers the front frame 82 and the front plates 120a and 120b of the frame housing 80, the handles 124 of the front plates 120a and 120b are also covered. Therefore, in this embodiment, as shown in Fig. 6, the inner cover 90 is provided with recesses 91 for accessing the handles 124 provided on the front plates 120a and 120b.

[0062] 11 is a cross-sectional view taken along line AA in FIG. 8(a), and FIG. 12 is a cross-sectional perspective view of the inner cover 90. As shown in FIG. As shown in Figures 11 and 12, the recess 91 of the inner cover 90 is located directly below the handle 124, and a hole 91a is formed in the upper surface of the recess 91 to allow a service person to access the handle 124.

[0063] When pulling out the intermediate transfer unit 7 from the device body, a service person can access the handle 124 by inserting his / her finger into the hole 91a of the recess 91. This allows the intermediate transfer unit 7 to be pulled out from the device body by grasping the handles 124 provided on the front panels 120a, 120b without removing the inner cover 90. This simplifies the work of pulling out the intermediate transfer unit 7 compared to removing the inner cover 90 and pulling out the intermediate transfer unit 7.

[0064] By pulling out the intermediate transfer unit 7 and removing the tension applying mechanism 160, the intermediate transfer belt 8 slackens from the state shown by the solid line in Fig. 13 to the state shown by the two-dot chain line. By slackening the intermediate transfer belt 8, the primary transfer rollers 9Y, 9M, 9C, and 9K in the loop of the intermediate transfer belt 8 and the secondary transfer opposing roller 12 can be removed from the frame housing 80 and replaced with new rollers.

[0065] When replacing the intermediate transfer belt 8, the tension applying mechanism 160 is removed, and then the inner cover 90 and the front panels 120a and 120b are removed.

[0066] FIG. 14 shows a state in which the inner cover 90 and the front panels 120a and 120b have been removed. 14, the front frame 82 is shorter than the distance from one horizontal frame to the other horizontal frame in the left-right direction of the device, and a predetermined gap S is formed between the front frame 82 of the frame housing 80 and the horizontal frame 85. By removing the inner cover 90 and the front plates 120a, 120b, a path for moving the intermediate transfer belt 8 to the front side is created. This allows the slack intermediate transfer belt 8 to pass through this gap S and be removed from the intermediate transfer unit 7.

[0067] Thus, in this embodiment, when replacing the intermediate transfer belt 8, it is necessary to remove the inner cover 90. However, when replacing the tension applying mechanism 160, the lubricant application device 200, the belt cleaning device 100, and tension rollers such as the primary transfer rollers 9Y, 9M, 9C, and 9K in the loop of the intermediate transfer belt 8 and the secondary transfer opposing roller 12, which are supported by the intermediate transfer unit 7 (frame housing 80), they can be replaced without removing the inner cover 90, as described above. This makes it possible to shorten the maintenance work time for the intermediate transfer unit.

[0068] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.

[0069] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In the intermediate transfer unit 7, which is provided with an intermediate transfer belt 8 and a housing such as a frame housing 80 that supports at least a tension roller that stretches the intermediate transfer belt 8, and is arranged to be removable from the main body of the image forming apparatus, a gripping portion such as a handle 124 that an operator such as a serviceman grasps when removing the intermediate transfer unit 7 is provided on the downstream side in the removal direction and on a downstream side panel of the housing (in this embodiment, composed of a front frame 82 and a pair of front panels 120) perpendicular to the removal direction, and has a cover member such as an inner cover 90 that covers the downstream side panel, and the cover member has a hole portion 91a through which the operator can access the gripping portion. Various mechanisms and members are supported on the housing of the intermediate transfer unit, such as a tension roller that stretches the intermediate transfer belt, a tension applying mechanism that applies tension to the intermediate transfer belt, a drive unit that rotates and drives the intermediate transfer belt, and a belt cleaning mechanism that cleans the surface of the intermediate transfer belt. The housing has high rigidity so that the housing does not deform even when supporting these mechanisms and members. As in Patent Document 1, by providing a gripping portion such as a handle that a serviceman or other worker grasps when pulling out the intermediate transfer unit from the main body of the image forming apparatus on the housing with high rigidity, it is possible to prevent the intermediate transfer unit from deforming when pulling out the intermediate transfer unit. A member such as a motor constituting a mechanism supported by the housing is attached to the surface where the grip part of the downstream side panel, such as the front panel of the housing, and a part of the mechanism or a part of the member penetrates the downstream side panel and protrudes from the surface where the grip part is provided. Therefore, for example, when a user removes jammed paper from the sheet transport path located below the intermediate transfer unit through the opening of the image forming device main body from which the intermediate transfer unit is pulled out for jam clearance, the user may inadvertently touch the member constituting the mechanism supported on the surface where the grip part of the intermediate transfer unit is provided in the attached state to the device main body or the mechanism or member protruding from the surface where the grip part is provided. In contrast, in the first aspect, by covering the downstream side plate of the housing with a cover member, it is possible to cover with the cover member the members constituting the mechanism supported by the housing attached to the surface on which the grip portion of the downstream side plate is provided, and a part of the mechanism or a part of the member that penetrates the downstream side plate and protrudes from the surface on which the grip portion is provided. This makes it possible to prevent a user from accidentally touching the members constituting the mechanism supported by the housing attached to the surface on which the grip portion of the downstream side plate is provided, and a part of the mechanism or a part of the member that penetrates the downstream side plate and protrudes from the surface on which the grip portion is provided. In addition, the cover member has a hole for allowing a serviceman or other worker to access the grip portion provided on the downstream side panel, so that the serviceman or other worker can access the grip portion and pull out the intermediate transfer unit from the main body of the image forming device without removing the cover member, thereby simplifying the operation of pulling out the intermediate transfer unit from the main body of the image forming device.

[0070] (Aspect 2) In aspect 1, both ends of the downstream side panel (in this embodiment, composed of a front frame 82 and a pair of front panels 120) are fastened to the main body of the image forming apparatus by fastening members such as screws 125, and a cover member such as an inner cover 90 has a fall prevention portion such as a screw guide hole 92 that prevents the fastening members from falling when the cover member is released from the main body of the image forming apparatus. This makes it possible to prevent fastening members such as the screws 125 from falling into the image forming apparatus main body, as described in the embodiment.

[0071] (Aspect 3) In the first or second embodiment, a tension applying mechanism 160 that applies tension to the intermediate transfer belt 8 is provided, and the tension applying mechanism 160 is configured to be removable from a housing such as the frame housing 80 without removing a cover member such as the inner cover 90. According to this, as described in the embodiment, the tension roller and the like can be replaced without removing the cover members such as the inner cover 90, and the maintenance work of the intermediate transfer unit can be simplified.

[0072] (Aspect 4) In any of aspects 1 to 4, a detachable unit (in this embodiment, this corresponds to the lubricant application device 200 and the belt cleaning device 100) is provided that is detachable from the intermediate transfer unit 7, and an opening / closing member such as a transfer small door 70 is provided that is rotatable between a path closing position that closes the attachment / detachment path of the detachable unit and a path opening position that opens the attachment / detachment path. Detachable units (which correspond to the lubricant application device 200 and the belt cleaning device 100 in this embodiment) that are detachable from the intermediate transfer unit 7 can be attached and detached without removing cover members such as the inner cover 90.

[0073] (Aspect 5) In the fourth embodiment, a tension applying mechanism 160 that applies tension to the intermediate transfer belt 8 is provided, and the tension applying mechanism 160 has a guide portion 165 that guides the attachment and detachment of a detachable unit such as the lubricant application device 200. According to this, as described in the embodiment, a detachable unit such as the lubricant application device 200 can be easily attached and detached.

[0074] (Aspect 6) In an image forming apparatus equipped with an intermediate transfer unit 7, the intermediate transfer unit according to any one of the embodiments 1 to 5 was used as the intermediate transfer unit 7. This makes it possible to simplify the maintenance work for the intermediate transfer unit. [Explanation of symbols]

[0075] 7: Intermediate transfer unit 8: Intermediate transfer belt 9C: Primary transfer roller 9K: Primary transfer roller 9M: Primary transfer roller 9Y: Primary transfer roller 10: Driven roller 11: Drive roller 12: Secondary transfer facing roller 13: Cleaning facing roller 14: Cleaning facing roller 15: Cleaning facing roller 16: Tension roller 17: Application brush facing roller 18: Secondary transfer roller 60: Printer 60a: Opening 61a: Front door 61b: Front door 66: Front side plate 66a: Screw hole 70: Small door with transcription 70a: opening 75: Locking member 75b: Operation section 80: Frame housing 81: Slide rail 82: Previous frame 82a: Locating pin 82b: Locating pin 83: Rear frame 84: Stay member 85: Horizontal frame 90: Inner cover 91: Recess 91a: Hole 92: Screw guide hole 100: Belt cleaning device 120a: Front plate 120b: Front plate 122: Positioning hole 123: Positioning hole 124: Handle 125: Screw 160: Tensioning mechanism 161: Base member 162: Positioning surface 162a: Positioning hole 162b: Positioning hole 162c: Screw through hole 163: Holder holding plate 165: Guide section 169: Screw 180a: Drive motor 180b: Drive motor 181: Cable 190: Cleaning lock lever 200: Lubricant application device 203: Lubricated lock lever L: Laser light P: Recording paper S: Gap [Prior art documents] [Patent documents]

[0076] [Patent Document 1] Patent No. 5553213

Claims

1. An intermediate transfer unit includes an intermediate transfer belt and a housing that supports at least a tension roller that tensions the intermediate transfer belt, and is provided in a removable manner relative to a main body of an image forming apparatus, a gripping portion that an operator grips when pulling out the intermediate transfer unit is provided on a downstream side panel of the housing that is perpendicular to a pull-out direction and downstream of a pull-out direction of the intermediate transfer unit, A cover member for covering the downstream side panel is provided. The intermediate transfer unit according to claim 1, wherein the cover member has a hole through which the operator can access the grip portion.

2. 2. The intermediate transfer unit according to claim 1, Both ends of the downstream side plate are fastened to the main body of the image forming apparatus by fastening members, The intermediate transfer unit according to claim 1, wherein the cover member has a fall prevention portion that prevents the fastening member from falling when the fastening member is released from the main body of the image forming apparatus.

3. 2. The intermediate transfer unit according to claim 1, A tension applying mechanism is provided to apply tension to the intermediate transfer belt, The intermediate transfer unit is characterized in that the tension applying mechanism is removable from the housing without removing the cover member.

4. 2. The intermediate transfer unit according to claim 1, a detachable unit that is detachable from the intermediate transfer unit; An intermediate transfer unit comprising: an opening / closing member configured to be rotatable between a path closing position that closes an attachment / detachment path of the attachment / detachment unit and a path opening position that opens the attachment / detachment path.

5. 5. The intermediate transfer unit according to claim 4, A tension applying mechanism is provided to apply tension to the intermediate transfer belt, The intermediate transfer unit, wherein the tension applying mechanism includes a guide portion that guides the attachment and detachment of the detachable unit.

6. In an image forming apparatus equipped with an intermediate transfer unit, 2. An image forming apparatus comprising the intermediate transfer unit according to claim 1 as the intermediate transfer unit.

Images