Image forming device

Abstract

To provide an image forming apparatus that, when an electrical substrate is disposed overlapping a driving device with screws, can prevent the generation of an image defect and an unusual sound due to attachment of foreign substances generated with fastening of the screws to a drive gear.SOLUTION: A driving device 90 and a substrate holding plate 203 are attached to each other with columns 205. The columns 205 are separate members provided independent of the driving device 90 and the substrate holding plate 203 and sandwiched between the driving device 90 and the substrate holding plate 203. The columns 205 are fixed to holding plate fastening parts 204a to 204c with screws at one ends and fixed to fixation parts 207a to 207c of the substrate holding plate 203 with screws at the other ends. The provision of the columns 205 eliminates the need of fastening with screws to projection pieces cut up from a main support body 20 toward the substrate holding plate 203 in a conventional art. This prevents formation of through holes near portions of the main support body 20 to which the substrate holding plate 203 is fastened and prevents metal powder from entering the inside of the driving device 90 and being attached to a drive gear.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus using electrophotographic technology, such as a printer, a copier, a facsimile, or a multifunction machine. [Background technology]

[0002] Image forming devices such as printers, copiers, facsimiles, and multifunction machines that combine them are provided with rotating bodies, such as a photosensitive drum, a developing sleeve, and a drive roller for rotating an intermediate transfer belt, in the device body. In order to drive these rotating bodies, a drive device that aggregates a motor and drive gears is attached to the rear side plate of the image forming device. In addition, in order to reduce the size of the image forming device, electrical boards, such as a power supply control board that supplies power and a main control board that performs various control processes related to the image forming operation, are arranged on top of the drive device (Patent Document 1).

[0003] Conventionally, as in the device described in Patent Document 1, the electrical board is fastened by a screw to a protruding piece cut out from a flat portion of a metal support plate that supports a drive transmission mechanism so that the electrical board is disposed over the drive unit. Therefore, a through hole is provided at the base of the protruding piece in the support plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-102885 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the above-mentioned protrusion has a fastening hole for fastening a screw, but metal powder formed when the fastening hole is formed in the protrusion may remain in the fastening hole as shavings. In the case of the device described in the above-mentioned Patent Document 1, when a screw is inserted into the fastening hole and fastened, metal powder pushed out from the fastening hole by the screw may enter the drive device through the through hole of the above-mentioned support plate and adhere to the drive gear, etc. If the metal powder adheres to the drive gear, a rotational fluctuation occurs in the rotating body driven by the drive device, and there is a risk that image defects such as periodic band-like unevenness in shade (called banding, etc.) may occur in the image formed on the recording material. In addition, foreign matter attached to the drive gear may be caught in the drive gear, causing abnormal noise.

[0006] In view of the above problems, the present invention aims to provide an image forming device that can suppress the occurrence of poor images and abnormal noise caused by foreign matter adhering to the drive gear when an electrical board is stacked on top of a drive device using screws. [Means for solving the problem]

[0007] An image forming apparatus according to an embodiment of the present invention forms an image on a recording material, and includes a support frame that supports a rotating body, a drive source, a drive gear that transmits a drive force of the drive source to the rotating body, and a drive unit that holds the drive source on a first surface and rotatably supports the drive gear on a second surface opposite to the first surface. first Support and a second support portion that, together with the first support portion, forms a space for allowing the drive gear to be inserted therein and supports the drive gear together with the first support portion; and a drive unit having the above-mentioned when viewed from the direction of the rotation axis of the drive gear. first a board holding member for holding an electrical board, the board holding member being arranged so as to overlap with the support portion; First support part and the substrate holding member, and supports the substrate holding member. third support In the department One end is the first The support portion is fixed to the first surface side by a first fastening member, and the other end is fixed to the board holding member by a second fastening member. third support Department and The present invention is characterized by comprising: Effect of the Invention

[0008] According to the present invention, when an electrical board is stacked on top of a drive device using fastening members, it is possible to achieve a simple configuration that suppresses the occurrence of poor images and abnormal noise caused by foreign matter adhering to the drive gear when the fastening members are fastened. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram showing the rear side of the image forming apparatus. [Diagram 3] FIG. [Figure 4] FIG. 4 is a view of the drive unit as seen from the main support side. [Diagram 5] FIG. [Figure 6] FIG. 4 is a view of the drive unit as seen from the sub-support side. [Figure 7] FIG. 2A is a perspective view of a drive control board provided in a drive device, as viewed from above; FIG. 2B is a perspective view of a drive control board provided in a drive device, as viewed from below. [Figure 8] 5A to 5D are diagrams for explaining procedures for arranging a drive control board, where (a) is a first procedure, (b) is a second procedure, (c) is a third procedure, and (d) is a fourth procedure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Image forming device> The image forming apparatus of this embodiment will be described with reference to FIGS. 1 and 2. The image forming apparatus 101 shown in FIG. 1 is a full-color printer of an intermediate transfer type. The image forming apparatus 101 has image forming units PY, PM, PC, and PK that form toner images of yellow, magenta, cyan, and black, respectively. The image forming apparatus 101 forms a toner image on a recording material S in response to an image signal from an original reading device 102 provided vertically above or an external device (not shown) such as a personal computer. Examples of the recording material S include sheet materials such as paper, plastic film, and cloth. In this specification, the side on which a user stands when operating an operation panel (not shown) to operate the image forming apparatus 101 is referred to as the "front" and the opposite side is referred to as the "rear".

[0011] In the image forming apparatus 101 shown in FIG. 1, the image forming units PY, PM, PC, and PK are arranged in line along the moving direction (arrow R2 direction) of the intermediate transfer belt 116. The intermediate transfer belt 116 is an endless belt member that carries and conveys the toner images primarily transferred from the photosensitive drums 112Y, 112M, 112C, and 112K of the image forming units PY, PM, PC, and PK. The intermediate transfer belt 116 is stretched around each of the rotating bodies of the secondary transfer inner roller 116a, the tension roller 116b, the secondary transfer pre-roller 116c, and the tension roller 116d. The intermediate transfer belt 116 is moved in the moving direction by the secondary transfer inner roller 116a (rotating body, secondary transfer roller) that is rotationally driven by the drive device 90 (see FIG. 3) described later. That is, in this embodiment, the secondary transfer inner roller 116a also serves as a drive roller that drives the intermediate transfer belt 116.

[0012] The image forming apparatus 101 has a support frame 101A that supports units such as the photosensitive drums 112Y to 112K, the secondary transfer inner roller 116a, the tension roller 116b, the secondary transfer front roller 116c, the tension roller 116d, etc. The support frame 101A is made up of a front plate provided on the front side of the image forming apparatus 101, a rear plate provided on the rear side and supporting each unit together with the front plate, stays connecting the front plate and the rear plate, and multiple sheet metals such as pillars supporting the front plate, and is covered by an exterior cover (not shown) that constitutes the exterior of the image forming apparatus 101.

[0013] A secondary transfer outer roller 117 is disposed so as to sandwich the secondary transfer inner roller 116a and the intermediate transfer belt 116, forming a secondary transfer nip portion T2 that transfers the toner image on the intermediate transfer belt 116 to the recording material S. In the secondary transfer nip portion T2, the secondary transfer inner roller 116a and the secondary transfer outer roller 117 rotate to sandwich and transport the recording material S.

[0014] One or more cassettes 131 containing recording materials S are disposed below the image forming apparatus 101. The recording materials S contained in the cassettes 131 are supplied one by one from the cassettes 131 to the conveying path 60 by a feeding roller 151 in accordance with the image formation timing. The recording materials S are conveyed to a registration roller 170 disposed on the conveying path 60, and the registration roller 170 performs skew correction and timing correction on the recording materials S before conveying them toward the secondary transfer nip portion T2. ​​The cassette 131 is supported so as to be slidable relative to the support frame 101A. A user can refill the cassette 131 with recording materials S by pulling out the cassette 131 to the front side of the image forming apparatus 101.

[0015] The four image forming units PY, PM, PC, and PK included in the image forming apparatus 101 have substantially the same configuration, except that the colors of toner used in the developing devices 114 that each unit has are different. Therefore, the yellow image forming unit PY will be described here as a representative, and descriptions of the other image forming units PM, PC, and PK will be omitted.

[0016] In the image forming section PY, a photosensitive drum 112Y is disposed as one of the rotating bodies. The photosensitive drum 112Y is rotationally driven by a driving device 90 (see FIG. 3), which will be described later. A charging device 113, a developing device 114, and a primary transfer roller 119 are disposed around the photosensitive drum 112Y.

[0017] When an image forming operation is started, first, the surface of the rotating photosensitive drum 112Y is uniformly charged by the charging device 113. Next, the photosensitive drum 112Y is scanned and exposed by a laser beam emitted from an exposure device 110 shared by the image forming units PY to PK. As a result, an electrostatic latent image corresponding to an image signal is formed on the photosensitive drum 112Y. The electrostatic latent image on the photosensitive drum 112Y is developed by toner (developer) in the developing device 114, and a toner image is formed on the photosensitive drum 112Y. The developing device 114 includes a conveying screw (not shown) that circulates and conveys the developer in a developing container, a developing sleeve 114a (rotating body) that carries the developer and rotates to supply the developer to the photosensitive drum 112Y, and the like. The developing sleeve 114a is driven by a driving device 90 (see FIG. 3) described later.

[0018] The toner image formed on the photosensitive drum 112Y is primarily transferred from the photosensitive drum 112Y to the intermediate transfer belt 116 at a primary transfer portion formed between the photosensitive drum 112Y and a primary transfer roller 119 disposed across the intermediate transfer belt 116. At this time, a primary transfer voltage is applied to the rotating primary transfer roller 119. In this manner, the intermediate transfer belt 116 rotates while carrying the toner image transferred from the photosensitive drum 112Y.

[0019] The above-mentioned operations are sequentially performed in the image forming units PY to PK for yellow, magenta, cyan, and black, so that a toner image can be formed on the intermediate transfer belt 116. For example, a single-color toner image can be formed, or a toner image of a desired color can be formed by appropriately superimposing some of the four colors. In accordance with the timing of forming such a toner image, the recording material S supplied from the cassette 131 is conveyed to the secondary transfer nip portion T2 via the registration roller 170. Then, for example, a secondary transfer voltage is applied to the secondary transfer outer roller 117 by a high-voltage power source (not shown), so that the toner image on the intermediate transfer belt 116 is secondarily transferred to the recording material S when the recording material S passes through the secondary transfer nip portion T2.

[0020] The recording material S onto which the toner image has been transferred from the intermediate transfer belt 116 is conveyed to the fixing device 120. The fixing device 120 applies heat and pressure to the recording material S while nipping and conveying the recording material S, thereby fixing the toner image to the recording material S. In the case of a single-sided printing mode in which a toner image is formed only on one side of the recording material S, the recording material S onto which the toner image has been fixed by the fixing device 120 is discharged to a recording material discharge section 123. On the other hand, in the case of a double-sided printing mode in which a toner image is formed on both sides of the recording material S, after the toner image has been fixed on one side by the fixing device 120, the recording material S is inverted by switchback conveyance and conveyed toward the registration roller 170 through the double-sided conveyance path 61. Thereafter, the recording material S undergoes the same process as in the single-sided printing mode, a toner image is also formed on the other side by the fixing device 120, and then the recording material S is discharged to the recording material discharge section 123.

[0021] In this embodiment, the intermediate transfer belt 116 , the secondary transfer inner roller 116 a , the tension roller 116 b , the secondary transfer front roller 116 c , the tension roller 116 d , and the plurality of primary transfer rollers 119 form an intermediate transfer unit 300 .

[0022] The image forming apparatus 101 can not only form a multi-color image, but also form a monochrome black image using only the image forming unit PK. When forming a monochrome black image, the primary transfer rollers 119 other than the black one are separated from the intermediate transfer belt 116 by a primary transfer roller separating mechanism (not shown) driven by a drive device 90 (see FIG. 3) described later.

[0023] 2 is a schematic diagram showing the rear side of the image forming apparatus 101 of this embodiment. The image forming apparatus 101 has an operation panel (not shown) on the front side for easy operation by a user, and a drive device 90 on the rear side. In this embodiment, the drive device 90 can drive the photosensitive drum 112, the secondary transfer inner roller 116a, the primary transfer roller separation mechanism (not shown), and the developing device 114 (more specifically, the developing sleeve 114a) shown in FIG. 1 above. The drive device 90 is attached to the rear side panel 10.

[0024] Further, various electrical boards (electrical system units) are disposed on the rear side of the image forming apparatus 101. The electrical boards are boards on which, for example, a CPU, a memory, electronic components, electric components, connectors, etc. are mounted. The electrical boards include, for example, a drive control board 200 that drives a motor, etc., a main control board 210 that transmits and receives various control signals (electrical signals) in response to execution of a program such as an image forming job, and a power supply control board 220 that receives power supply from an external power source and performs voltage adjustment, etc. The main control board 210 is connected to the drive control board 200, the power supply control board 220, etc. by a wire harness 202 so as to be able to transmit and receive electrical signals. Note that the electrical boards are not limited to those described above.

[0025] In this embodiment, in order to reduce the size of the image forming apparatus 101, at least one of the electrical boards is arranged so as to overlap the drive device 90. In the example shown in Fig. 2, the drive control board 200 is arranged on the drive device 90 so as to overlap with the drive device 90. The arrangement of the electrical boards on the drive device 90 in this embodiment will be described later (see Figs. 7(a) to 8(d)).

[0026] <Outline of the drive unit> The above-mentioned drive device 90 will be described using Figures 3 to 6 with reference to Figure 1. In order to facilitate understanding of the description, some or all of the arrangement of electrical boards in the drive device 90 (see Figures 7(a) and 7(b)) described below are omitted from Figures 3 to 6.

[0027] The driving device 90 has a main support 20 as a driving support part formed of, for example, a thin metal plate, and a metallic sub-support 25 (see FIG. 5). In this embodiment, the driving device 90 is fixed to the outside of the support frame 101A of the image forming apparatus 101, not to the inside of the support frame 101A. Here, the outside of the support frame 101A refers to the side covered by the exterior cover described above. Therefore, the driving device 90 can be accessed by removing the exterior cover of the image forming apparatus 101, and is therefore easier to maintain than a configuration in which the driving device 90 is fixed to the inside of the support frame 101A.

[0028] 3 and 4, the driving device 90 is attached to the rear plate 10 of the support frame 101A (see FIG. 1). The driving device 90 is fixed to the rear plate 10 by screws 41 via a plurality of fixing parts 55a-55h formed on the outer periphery of the main support 20, with the sub-support 25 facing the rear plate 10. Mounting holes for mounting the screws 41 for fastening the main body are formed in the fixing parts 55a-55h.

[0029] As shown in Fig. 3, the main support 20 has an outer peripheral wall 15 standing upright toward the rear plate 10 so as to surround the outer periphery, in order to prevent foreign matter such as dust from entering from the outside into a drive device 90 in which a drive gear (see Fig. 5) is arranged. The fixing portions 55a to 55h described above are formed by bending the outer peripheral wall 15 into an L-shape with respect to the wall surface thereof so that the tip of the outer peripheral wall 15 can abut against the rear plate 10 and be fixed to the rear plate 10 by screws 41. Note that, in the case where it is difficult to form the outer peripheral wall 15 continuously due to the processing of the sheet metal, and an opening is formed, the opening may be blocked with a sheet material or the like.

[0030] 3 and 4, a plurality of motors (30CL, 30K, 30S, 30Ga to 30Gd) are held on the first surface side of the main support 20 as drive sources for driving the rotating bodies rotatably supported by the rear side plate 10. Here, one motor 30CL for driving the yellow, magenta and cyan photosensitive drums 112Y, 112M and 112C, and one motor 30K for driving the black photosensitive drum 112K and the secondary transfer inner roller 116a are held. In addition, one motor 30S for driving the above-mentioned primary transfer roller separation mechanism (not shown), and four motors 30Ga, 30Gb, 30Gc and 30Gd for individually driving the yellow, magenta, cyan and black developing devices 114 (more specifically, the developing sleeves 114a), respectively, are held.

[0031] On the other hand, on the second surface side of the main support 20 opposite to the first surface described above, as shown in Fig. 5, drive gears (35CLa-35CLc, 35Ka-35Ke, 35Sa-35Sc, 35Ga-35Gd) are provided to transmit the drive force of the motors (30CL, 30K, 30S, 30Ga-30Gd, see Fig. 4) to the rotating body of the support frame 101A. The drive gears 35CLa-35CLc transmit the drive force of the motor 30CL to the yellow, magenta, and cyan photosensitive drums 112Y, 112M, and 112C. The drive gears 35Ka-35Ke transmit the drive force of the motor 30K to the black photosensitive drum 112K and the inner secondary transfer roller 216a. Further, the driving gears 35Sa-35Sc transmit the driving force of the motor 30S to a primary transfer roller separation mechanism (not shown), and the driving gears 35Ga-35Gd transmit the driving forces of the four motors 30Ga-30Gd to the yellow, magenta, cyan, and black developing devices 114 (more specifically, developing sleeves 114a), respectively. Viscous grease is applied to the gear tooth surfaces of these driving gears (35CLa-35CLc, 35Ka-35Ke, 35Sa-35Sc, 35Ga-35Gd) to ensure lubrication and quiet operation during rotation.

[0032] The driving gears 35CLa to 35CLc have couplings for transmitting drive to the yellow, magenta, and cyan photosensitive drums 112Y to 112C. The driving gears 35Ka to 35Ke have couplings for transmitting drive to the black photosensitive drum 112K and the secondary transfer inner roller 216a. Each of these couplings is exposed from a through hole provided in the second support portion 25a of the sub-support 25, and is capable of transmitting a drive force to each unit. Meanwhile, the portions of the driving gears 35CLa to 35CLc and the driving gears 35Ka to 35Ke having tooth surfaces for transmitting drive are arranged in a space covered by the main support 29 and the sub-support 25. The drive gears 35Ga to 35Gd are disposed in a space covered by the main support 20 and the sub-support 25, and other gears to which the drive force is transmitted from the drive gears 35Ga to 35Gd and couplings to which the drive force is transmitted from these other gears are provided outside the sub-support 25, thereby transmitting the drive force to the four developing devices 114. These couplings protrude into the inside of the support frame 101A from through holes provided in the rear side plate 10 of the support frame 101A, thereby making it possible to transmit the drive force to each unit supported by the support frame 101A.

[0033] The main support 20 and the sub-support 25 are disposed at both ends of the drive gears (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd) in the direction of the rotation axis, and each of them rotatably supports the rotation shaft of the drive gear. The main support 20 has a first support portion 20a that supports one end of the rotation shaft of the drive gear, and the sub-support 25 has a second support portion 25a that supports the other end of the rotation shaft of the drive gear. In this embodiment, the surfaces of the first support portion 20a and the second support portion 25a that support the drive gears (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd) are flush with each other, but either or both of the first support portion 20a and the second support portion 25a may have irregularities or steps.

[0034] The main support 20 and the sub-support 25 are arranged and connected to sandwich the drive gears (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd). In this embodiment, the main support 20 has a larger area than the sub-support 25 and is more rigid than the sub-support 25. Therefore, in this embodiment, in order to connect the main support 20 and the sub-support 25, the sub-support 25 is fastened to the main support 20 by a screw 40 (distinguished from the screw 41 for fastening to the main body, see FIG. 6). The sub-support 25 is arranged upstream of the fastening direction (insertion direction, arrow X direction in FIG. 5) in which the screw 40 is fastened to the main support 20.

[0035] In the main support 20, out-of-plane fastening holes 560 and in-plane fastening holes 570 for fastening the screws 40 are formed in the first support portion 20a. On the other hand, in the sub-support 25, out-of-plane mounting portions 260a to 260d and in-plane mounting portions 270a to 270c are formed for inserting and mounting the screws 40.

[0036] The fastening configuration of the main support 20 and the sub-support 25 in the drive device 90 using the screws 40 will be described. The first support portion 20a of the main support 20 is formed with an in-plane fastening hole 570 for fastening the screw 40, and the sub-support 25 is formed with in-plane mounting portions 270a-270c for inserting and mounting the screw 40. The in-plane fastening hole 570 of the main support 20 is formed in a projection plane obtained by projecting the second support portion 25a of the sub-support 25 in the rotation axis direction of the drive gears (35CLa-35CLc, 35Ka-35Ke, 35Sa-35Sc, 35Ga-35Gd, see FIG. 5) in the first support portion 20a. The projection surface of the second support portion 25a is a projection surface of the outer periphery represented by connecting the outermost edges of the surface supporting the drive gears (35CLa-35CLc, 35Ka-35Ke, 35Sa-35Sc, 35Ga-35Gd) of the second support portion 25a, and is the area indicated by dashed lines in Figures 5 and 6.

[0037] 5, the in-plane mounting portions 270a to 270c of the sub-support 25 extend from the second support 25a toward the downstream side (first support 20a side) in the fastening direction of the screw 40 so as to abut against the first support 20a in the projection plane. The in-plane mounting portions 270a to 270c have in-plane mounting holes 27 for inserting and mounting the screws 40 at positions that overlap with the in-plane fastening holes 570 of the main support 20 at the abutting portions that abut against the first support 20a. These in-plane mounting portions 270a to 270c are formed such that a part of the second support 25a is cut and bent toward the main support 20 side (first support side).

[0038] In this embodiment, the main support 20 is fixed to the rear plate 10 (support frame) of the support frame 101A (see FIG. 1) with the sub-support 25 facing the rear plate 10. When the main support 20 and the sub-support 25 are connected, the tip of the screw 40 (more specifically, the tip of the threaded portion) protrudes from the downstream side of the fastening direction of the in-plane fastening hole 570. However, in this embodiment, when the main support 20 and the sub-support 25 are connected, the downstream end of the fastening direction of the in-plane fastening hole 570 (the back side of the fastening portion) is located at a position that does not overlap the space sandwiched between the first support portion 20a and the second support portion 25a when viewed from the gravity direction. That is, it is located outside the drive device 90 and does not overlap with each drive gear (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd) arranged between the first support portion 20a and the second support portion 25a.

[0039] In this embodiment, the main support 20 has an out-of-plane fastening hole 560 for fastening the screw 40 outside the projection plane of the first support 20a, as shown in FIG. 6. On the other hand, the sub-support 25 has out-of-plane mounting parts 260a-260d extending from the second support 25a toward the downstream side (first support 20a side) in the fastening direction of the screw 40 so as to abut against the first support 20a outside the projection plane. The out-of-plane mounting parts 260a-260d have out-of-plane mounting holes 261 for inserting and mounting the screw 40. That is, in this embodiment, in order to more firmly fix the sub-support 25 to the main support 20, the out-of-plane mounting parts 260a-260d provided at positions other than the in-plane mounting parts 270a-270c can also be fixed. The out-plane mounting portions 260a to 260d and the in-plane mounting portions 270a to 270c are disposed inside the outer periphery of the first support portion 20a of the main support 20 so as to abut against the first support portion 20a.

[0040] <Configuration of control board for drive unit> In this embodiment, an electrical board (as an example, the drive control board 200) is disposed on top of the drive device 90 (see FIG. 2). The arrangement of the electrical board on the drive device 90 in this embodiment will be described using the drive control board 200 as an example with reference to FIGS. 4 and 5 and with reference to FIGS. 7(a) to 8(d).

[0041] As shown in FIG. 7(a) and FIG. 7(b), the drive control board 200 is disposed on the rear side of the drive device 90. The drive control board 200 given as an example is a board that controls the operation of, for example, the motors (30CL, 30K, 30S, 30Ga to 30Gd, see FIG. 4) of the drive device 90, a fan motor, a conveyor motor, and the like (not shown). The drive control board 200 has a plurality of connectors 201, and is connected to, for example, a main control board 210 (see FIG. 2) and each of the above-mentioned motors via wire harnesses 202 that can be inserted into and removed from the connectors 201, and controls the operation of each motor according to the control of the main control board 210. The connectors 201 are disposed as dispersed as possible within the mounting surface of the drive control board 200 from the viewpoint of ease of insertion and removal of the wire harnesses 202. This is preferable because it reduces overlapping between the wire harnesses 202 and improves ease of insertion and removal of the wire harnesses 202.

[0042] However, if a dedicated installation space is provided for each of all the electrical boards (main control board 210, power supply control board 220) including the drive control board 200, the image forming apparatus 101 will have to be enlarged, which goes against the recent demand for miniaturization. Therefore, as shown in Fig. 7(a) and Fig. 7(b), by arranging at least one of the multiple electrical boards (here, the drive control board 200) so as to overlap the drive device 90, it is possible to realize the arrangement of the electrical boards taking into consideration the current space without enlarging the image forming apparatus 101. In this embodiment, the drive control board 200 is arranged so as to overlap the drive device 90 when viewed from the direction of the rotation axis (arrow Y direction) of the drive gears (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd, see Fig. 5).

[0043] Note that the drive device 90 may be provided with electrical boards other than the drive control board 200 (main control board 210, power supply control board 220), and if the drive device 90 has space for providing multiple electrical boards, multiple electrical boards may be provided in the drive device 90. In this case, the electrical boards may be appropriately combined and provided in the drive device 90, taking into consideration the area of ​​the drive device 90 and the area of ​​each of the multiple electrical boards.

[0044] However, it is preferable that the drive control board 200, which controls the motors (30CL, 30K, 30S, 30Ga to 30Gd, see FIG. 4) and the like provided in the drive device 90, is disposed in the drive device 90. That is, since the drive control board 200 is connected to a larger number of wire harnesses 202 than other electrical boards in order to control a plurality of motors and the like, it is preferable that the drive control board 200 is disposed in the drive device 90 (see FIG. 2) disposed in the middle position of the support frame 101A. In this way, the length of the many wire harnesses 202 can be shortened, and the wiring process of the wire harnesses 202 can be simplified. If the wire harnesses 202 can be shortened, the influence of external noise on the signals transmitted and received through the wire harnesses 202 can be suppressed, and costs can be reduced.

[0045] In the present embodiment, the drive control board 200 is disposed in the drive device 90 in a state where it is preassembled and held by the board holding plate 203 as a board holding member. In this manner, the drive control board 200 is attached to and detached from the drive device 90 while being held by the board holding plate 203, which has higher rigidity than the electrical board, and therefore can be easily attached and detached by an operator. In addition, since a tool used for attachment and detachment is unlikely to hit the drive control board 200, damage to the drive control board 200 caused by hitting the tool during attachment and detachment can be suppressed. Note that, when a plurality of electrical boards are disposed in the drive device 90, it is preferable to hold the plurality of electrical boards on one board holding plate 203, but each of the plurality of electrical boards may be held on a different board holding plate 203. In addition, the electrical boards such as the drive control board 200 may be detachably held on the board holding plate 203.

[0046] In this embodiment, in order to attach the substrate holding plate 203 to the driving device 90 with screws, a plurality of holding plate fastening parts 204a, 204b, 204c, 204d, and 204e are formed on the main support 20 (see FIGS. 4, 7(a), and 7(b)). In order to make it easy for an operator to attach and detach the substrate holding plate 203, the holding plate fastening parts 204a to 204e are formed on the outside of the substrate holding plate 203 so as not to overlap with the substrate holding plate 203 (see FIG. 8(d)).

[0047] Incidentally, when the drive control board 200 is disposed on top of the drive device 90, it is necessary to provide a gap so as not to contact the motors (30CL, 30K, 30S, 30Ga to 30Gd, see FIG. 4) and the like. Conventionally, as already described, a part of the first support portion 20a is cut and bent toward the substrate holding plate 203 to form a protruding piece protruding from the first support portion 20a toward the substrate holding plate 203. In this case, a through hole is formed at the base of the protruding piece in the first support portion 20a. Therefore, when a screw is inserted into a fastening hole formed in the protruding piece to fasten the substrate holding plate 203, metal powder pushed out from the fastening hole by the screw may enter the drive device 90 through the through hole and adhere to the drive gears (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd, see FIG. 5) and the like. Metal powder adhering to the drive gear is undesirable because it can cause image defects such as uneven density in the image formed on the recording material and abnormal noises.

[0048] In consideration of this point, in this embodiment, as shown in FIG. 7(a), in the holding plate fastening parts 204a to 204c located above the driving gear in the gravity direction, the driving device 90 and the substrate holding plate 203 are attached via a plurality of (three in this embodiment) supports 205. The supports 205 as supporting members are separate members provided independently of the driving device 90 and the substrate holding plate 203, and are sandwiched between the driving device 90 (specifically, the first support part 20a) and the substrate holding plate 203 at the positions of the holding plate fastening parts 204a to 204c. One end of each of the supports 205 is fixed to the holding plate fastening parts 204a to 204c by a screw 45 as a first fastening member (see FIG. 7(a)). The other end of each of the supports 205 is fixed to the fixing parts 207a to 207c of the substrate holding plate 203 by a screw 46 as a second fastening member (see FIG. 8(d)). By providing such separate support posts 205, in the upper holding plate fastening portions 204a to 204c, the substrate holding plate 203 can be fixed to the main support 20 without forming through holes as in the conventional art in the first support portion 20a.

[0049] On the other hand, as shown in Fig. 7(b), the holding plate fastening parts 204d, 204e below the drive gear in the direction of gravity are formed by cutting a part of the lower surface 111c of the main support 20 (in other words, the outer peripheral wall 15 on the lower surface side of the main support 20) and bending it toward the substrate holding plate 203. The substrate holding plate 203 is provided with fixing parts 207d, 207e that protrude toward the holding plate fastening parts 204d, 204e and are fixed with screws. When the holding plate fastening parts 204d, 204e are formed, the through hole 111d is formed in the lower surface 111c, but even if the through hole 111d is formed from the lower surface 111c, the holding plate fastening parts 204d, 204e are located below the drive gear (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd, see Fig. 5) in the direction of gravity. Therefore, there is no risk of foreign matter (metal powder) entering the driving device 90 through the through hole 111d. Therefore, in the holding plate fastening parts 204d and 204e, the substrate holding plate 203 can be fixed to the main support 20 with screws without using the above-mentioned support pillars 205.

[0050] Incidentally, the substrate holding plate 203 and the main support 20 may be fixed to each other at all fixing points using the support columns 205, without drilling through holes in the main support 20 as described above. However, if there is no risk of foreign matter entering the drive device 90 through the through holes as described above, forming the holding plate fastening parts 204d, 204e as described above and enabling fixing without using the support columns 205 has the advantage of being able to reduce costs by reducing the number of parts.

[0051] 7(a) and 7(b), the substrate holding plate 203 may be provided with a locking portion 240 for hooking the substrate holding plate 203 on the support 205 to temporarily hold the substrate holding plate 203 on the support 205. Alternatively, the support 205 may be provided with the locking portion 240. This allows the substrate holding plate 203 to be temporarily held when the worker fastens the substrate holding plate 203 to the support 205 during maintenance or other work, improving workability. In addition, in a state in which the substrate holding plate 203 is fixed to the support 205 with the screw 46, the substrate holding plate 203 is fixed to the main support 20 with the screw 45 in an area overlapping the substrate holding plate 203. In other words, the worker cannot remove the support 205 from the main support 20 unless the worker first removes the substrate holding plate 203 from the support 205. In this way, workers will not mistakenly remove the support pillars 205 from the main support body 20 during maintenance or other work, so no metal powder will be generated when the screws are fastened, and no metal powder will enter the drive mechanism 90.

[0052] <Installation Procedure> Next, the procedure for installing the drive control board 200 (specifically, the board holding plate 203) on the drive device 90 will be described step by step with reference to Fig. 8(a) to Fig. 8(d). Note that in Fig. 8(a) to Fig. 8(d), in order to make the description easier to understand, some parts such as the screws and the motor 30S are omitted from the illustration.

[0053] First, as shown in FIG. 8(a), in the first step, the motors (30CL, 30K, 30Ga-30Gd) and the support pillars 205 are fixed to the first support portion 20a of the main support 20 before the sub-support 25 is attached. At this time, one end of the support pillars 205 is fastened to the above-mentioned holding plate fastening portions 204a-204c by screws. Then, as shown in FIG. 8(b), in the second step, the drive gears (35CLa-35CLc, 35Ka-35Ke, 35Ga-35Gd) are attached to the second surface side of the first support portion 20a opposite to the one surface side where the motor and the support pillars 205 are fastened. In this way, the motor and the support pillars 205 are fastened to each other by screws before the drive gears are attached, so that even if metal powder is generated at that time, it does not adhere to the drive gears.

[0054] 8(c), in the third step, the sub-support 25 is fastened to the main support 20 by using a screw. Here, as described above, in the case of this embodiment, when the main support 20 and the sub-support 25 are connected, the tip of the screw protrudes from the downstream side of the fastening direction of the in-plane fastening hole 570. Therefore, even if metal powder is generated by fastening with the screw, the metal powder is pushed out to the outside of the drive device 90 and does not adhere to the drive gear.

[0055] 8(d), in a fourth step, the drive control board 200 is attached to the drive device 90 while being held by the board holding plate 203. The board holding plate 203 is fastened to the other end of the support 205 by screws via fixing parts 207a to 207c, and is also fastened to holding plate fastening parts 204d, 204e by screws via fixing parts 207d, 207e. In this way, the board holding plate 203 is fastened on the upper side by a separate support 205 prepared separately from the main support 20, and is fastened on the lower side to holding plate fastening parts 204d, 204e formed by cutting out the main support 20.

[0056] As described above, when the electric board is arranged on the driving device 90, the board holding plate 203 holding the electric board is fastened by screws to the separate support 205 prepared separately from the main support 20. In this embodiment, the separate support 205 is used and the board holding plate 203 is fastened to it by screws, so that the support 205 can be attached before attaching the driving gear (35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd). As a result, when fastening the board holding plate 203 to the driving device 90, it is not necessary to fasten the board directly to the first support part 20a supporting the driving gear. Also, it is not necessary to fasten the board to a protruding piece cut and raised from the main support 20 toward the board holding plate 203 side by screws as in the conventional case. Therefore, even if metal powder is generated when the substrate holding plate 203 is fastened with the screws, the metal powder does not enter the inside of the drive device 90 because there is no through hole in the main support 20 near the portion where the substrate holding plate 203 is fastened. Therefore, the metal powder generated when the substrate holding plate 203 is fastened with the screws cannot adhere to the drive gear, and image defects such as uneven shading and abnormal noises do not occur in the image formed on the recording material.

[0057] <Other embodiments> In the above-described embodiment, the support pillars 205 are fastened to the substrate holding plate 203 by screws, but the present invention is not limited to this. For example, if the support pillars 205 are separate from the substrate holding plate 203, the support pillars 205 may be fixed to the substrate holding plate 203 by welding. Even with this configuration, since the support pillars 205 are separate from the substrate holding plate 203, metal powder does not enter the inside of the drive device 90. Therefore, metal powder generated by fastening with screws cannot adhere to the drive gear, and image defects such as uneven shading and abnormal noises do not occur in the image formed on the recording material.

[0058] In the above-described embodiment, the image forming apparatus 101 is described as an intermediate transfer type in which the toner image is primarily transferred from the photosensitive drums 112Y-112K of each color to the intermediate transfer belt 116, and then the toner image is secondarily transferred from the intermediate transfer belt 116 to the recording material S, but the present invention is not limited to this. The above-described embodiment is also applicable to a direct transfer type image forming apparatus in which the toner image is directly transferred to the recording material S from the photosensitive drums 112Y-112K of each color that rotate while carrying the toner image. [Explanation of symbols]

[0059] 10...support frame (rear side plate), 20...drive support portion (main support), 30CL, 30K, 30S, 30Ga to 30Gd...drive source (motor), 35CLa to 35CLc, 35Ka to 35Ke, 35Sa to 35Sc, 35Ga to 35Gd...drive gear, 45...first fastening member (screw), 46...second fastening member (screw), 90...drive device, 101...image forming device, 112...rotating body (photosensitive drum), 114a...rotating body (developing sleeve), 116a...rotating body (secondary transfer roller, secondary transfer inner roller), 200...electrical board (drive control board), 203...board holding member (board holding plate), 205...support member (pillar), 240...locking portion, S...recording material

Claims

1. In an image forming apparatus for forming an image on a recording material, A support frame that supports the rotating body; a drive device including a drive source, a drive gear that transmits a drive force of the drive source to the rotating body, a first support portion that holds the drive source on a first surface and rotatably supports the drive gear on a second surface opposite to the first surface, and a second support portion that forms a space for accommodating the drive gear together with the first support portion and supports the drive gear together with the first support portion; a board holding member that holds an electrical board and is arranged so as to overlap with the first support portion when viewed from the rotation axis direction of the drive gear; a third support portion that is disposed between the first support portion and the substrate holding member in the direction of the rotation axis and supports the substrate holding member, the third support portion having one end fixed to the first surface side of the first support portion by a first fastening member and the other end fixed to the substrate holding member by a second fastening member; 1. An image forming apparatus comprising:

2. the third support portion is fixed by the first fastening member in a region overlapping with the substrate holding member of the first support portion such that the first fastening member is inaccessible in a state in which the substrate holding member is fixed by the second fastening member, as viewed from the direction of the rotation axis; 2. The image forming apparatus according to claim 1,

3. The third support portion is fixed by the first fastening member at a position above the drive gear in a gravitational direction in the first support portion.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

4. At least one of the substrate holding member and the third support portion has a locking portion that locks the substrate holding member to the third support portion temporarily when the substrate holding member is not fixed by the second fastening member.

4. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. The drive device is fixed to the support frame such that the second surface faces the support frame.

5. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

6. The electrical board is a board that controls the driving source.

6. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

7. The rotating body is a photosensitive drum that rotates while carrying a toner image.

7. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

8. the rotating body is a developing sleeve which carries toner and rotates to develop a toner image on the photosensitive drum; 7. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

9. The rotating body is a secondary transfer roller that forms a nip portion for secondary transfer of a toner image formed on a photosensitive drum from an intermediate transfer belt to a recording material.

7. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

Images