Image forming device

Abstract

To prevent fall-off of compression springs that constitute a conduction path used in an image forming apparatus.SOLUTION: A compression spring that is in contact with a conduction path for establishing conduction between a first unit and a second unit and is held by a holding member is a compression spring that has a spring cylindrical part and an arm part extending from an end of the spring cylindrical part to the outside in a radial direction. The arm part has a first part that extends to the outside in the radial direction with respect to the spring cylindrical part, and a second part that is bent at a first bending part such that the angle formed with the first part becomes an acute angle, the second part extending such that an end on the opposite side of the first bending part approaches the spring cylindrical part.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] Conventionally, spring contacts such as compression springs have been used to electrically connect each unit having a photosensitive drum, developing member, etc. of an image forming apparatus to a high-voltage board. Patent Document 1 discloses a configuration in which process units such as a drum unit having a photosensitive drum and a developing unit having developing members are connected to a high-voltage board that supplies high voltage using spring contacts in which compression springs are integrally formed on both ends of a conductive wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-109781 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in order to connect the unit and the high-voltage board with an even simpler configuration than the connection configuration described in Patent Document 1, it is conceivable to configure the wire and the compression spring separately. In this case, by holding the compression spring in contact with the wire, electrical connection can be made with a simple configuration.

[0005] However, in the configuration in which the contact members are separated as described above, there was a risk that the compression spring would fall off if it was unintentionally touched during assembly or maintenance of the unit, making it difficult to work with during assembly or maintenance.

[0006] Therefore, an object of the present invention is to prevent deterioration of workability during assembly and maintenance even when a compression spring is used in the connection configuration between a unit used in an image forming apparatus and a high-voltage board. [Means for solving the problem]

[0007] The image forming apparatus includes a power supply unit that supplies power, a process unit that performs part of an image forming process using power supplied from the power supply unit, and a power supply path unit that provides a conductive path from the power supply unit to the process unit, the power supply path unit including a coil spring that constitutes a contact point with the power supply unit or the process unit as part of the conductive path, and a holding member that holds the coil spring, the coil spring having a coil portion and an arm portion that is integral with the coil portion and extends outward from one end of the coil portion along a radial direction of the coil portion, the holding member having a restricting portion that restricts movement of the coil spring in the radial direction, and the arm portion of the coil spring having a hook portion that engages with a part of the holding member. the holding member has a plate portion in contact with the one end of the coil portion and having a surface extending in the radial direction of the coil portion, the arm portion has a first portion extending outward from the one end of the coil portion in the radial direction relative to the coil portion, a second portion extending from an end of the first portion opposite the coil portion toward the coil portion in the radial direction via a first bent portion, and a third portion extending from an end of the second portion opposite the first portion via a second bent portion so as to move away outward from the coil portion in the radial direction, the first bent portion forming an acute angle, and the first portion and the second portion sandwiching the plate portion in the extension / contraction direction of the coil portion, so that the first portion and the second portion constitute the hook portion, and the third portion extends beyond the end of the plate portion in the radial direction. The present invention is characterized in that: Effect of the Invention

[0008] According to the present invention, even when a compression spring is used in the electrical contact path, it is possible to improve the workability during assembly and service replacement. [Brief description of the drawings]

[0009] [Figure 1] Schematic cross-sectional view of an image forming apparatus [Diagram 2] A perspective view of the rear side of the image forming apparatus [Diagram 3] Schematic perspective view of the vicinity of the high-voltage substrate [Figure 4] FIG. 1 is a perspective view showing a power supply path from a high-voltage board to a drum unit. [Diagram 5] Schematic diagram of high pressure path retaining member [Figure 6] Schematic diagram of the drum unit side contact of the high-pressure path retaining member [Figure 7]Schematic diagram showing a conventional compression spring holding configuration [Figure 8] 1 is a schematic diagram of a compression spring and a high pressure path retaining member according to a first embodiment; [Figure 9] FIG. 1 is a schematic diagram showing an assembled state of a compression spring according to a first embodiment; [Figure 10] FIG. 11 is a schematic diagram showing a configuration for supporting a compression spring according to a second embodiment; [Figure 11] FIG. 13 is a schematic diagram showing a compression spring according to a third embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <First embodiment> In the following, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described in the embodiments are not intended to limit the scope of the present invention.

[0011] 1 is a schematic cross-sectional view of an image forming apparatus 100 according to the present invention. An operation unit 200 having a touch panel that can be operated by a user is provided on the front side of the image forming apparatus 100. An image reading device 150 and a document transport device 300 are provided on the upper portion of the image forming apparatus 100.

[0012] The image reading device 150 can read an image of an original placed on a reading glass (not shown), and can also read an image of an original conveyed by the original conveying device 300 and passing over the flow reading glass. The image data read by the image reading device 150 is processed as image information by a controller board (not shown). Here, the user can give instructions to the image reading device 150 to execute reading, etc., via the operation unit 200.

[0013] The cassette 111 can accommodate paper, OHT, or the like as the sheet S on which an image is formed, and can be pulled out toward the front side of the image forming apparatus 100.

[0014] The above-mentioned controller board generates a signal to cause the laser scanner unit 142 to emit laser light, based on image information based on the result of reading by the image reading device 150 or image information input from an external device such as a PC.

[0015] Then, an electrostatic latent image is formed on the photosensitive drum 141 by laser light emitted from the laser scanner unit 142, and the electrostatic latent image on the photosensitive drum 141 is developed by a developing sleeve serving as a developing unit provided in the developing device 143, thereby forming a toner image on the photosensitive drum 141.

[0016] Here, the image forming unit 140 has four stations, Y, M, C, and Bk. The stations in the image forming unit 140 have the same configuration, except for the color of toner they use, cyan, magenta, yellow, and black. Therefore, the configuration of the image forming unit Y will be described here, and detailed descriptions of the configurations of the image forming units M, C, and K will be omitted.

[0017] A predetermined pressure and an electrostatic load bias are applied to the toner image formed on the photosensitive drum 141 by the primary transfer device 144 , and the toner image is transferred onto the intermediate transfer belt 145 .

[0018] Next, the intermediate transfer belt 145 will be described. The intermediate transfer belt 145 is driven to be transported in the direction of the arrow A in FIG. 1. Therefore, the above-mentioned Y, M, C, and Bk stations process the images in parallel. The image forming process of each station is performed at a timing to overlap the upstream toner image that has been primarily transferred onto the intermediate transfer belt 145. As a result, a full-color toner image is finally formed on the intermediate transfer belt 145, and is transported to the secondary transfer unit 130 as the intermediate transfer belt 145 rotates.

[0019] Meanwhile, sheets S, such as paper or OHT, stacked and stored in the above-mentioned cassette 111 are separated and fed one by one by a paper feed unit 110. The fed sheets S are delivered to a first conveying roller pair 120 and conveyed toward a sheet skew correction device 10 disposed downstream in the sheet conveying direction, where skew of the sheets S is corrected. Thereafter, the sheets S are conveyed to a secondary transfer unit 130 by a second conveying roller pair 30.

[0020] Then, the sheet S transported to the secondary transfer section 130 is sandwiched between the secondary transfer inner roller 131 and the secondary transfer outer roller 132 via the intermediate transfer belt 145, and a full-color toner image is secondarily transferred onto the sheet S at the secondary transfer section 130.

[0021] Thereafter, the sheet S is conveyed to a fixing device 155. The fixing device 155 applies a predetermined pressure by rollers or belts that are substantially opposed to each other, and generally applies a heating effect by a heat source such as a heater, thereby melting and fixing the toner on the sheet S.

[0022] The sheet S having the fixed image thus obtained passes through a post-fixing conveying section 160 and is discharged directly onto a paper discharge tray 170 by paper discharge rollers 161. When forming images on both sides of the sheet S, the paper discharge rollers 161 are rotated in the reverse direction, and the sheet S having the image formed on the first side is conveyed to a reversing conveying device 180, and is conveyed again by the first conveying roller pair 120 to a secondary transfer section 130, where an image is formed on the second side.

[0023] Moreover, each of the above units is held by a frame 500, which will be described later.

[0024] Next, a high-voltage power supply path to a drum unit 600 having a photosensitive drum 141 of the image forming apparatus of the present invention will be described with reference to Figures 2, 3 and 4. Figure 2 is a perspective view of the image forming apparatus 100 from the rear side with the exterior cover removed, where (a) is a perspective view of the high-voltage power supply path supported by a frame 500, and (b) is a perspective view of the high-voltage power supply path.

[0025] Here, the frame body 500 has a rear side plate 501 provided on the rear side of the image forming apparatus 100, a front side plate 502 provided on the front side of the image forming apparatus 100 and supporting each unit together with the rear side plate 501, and stays 503a-c connecting the rear side plate 501 and the front side plate 502.

[0026] High-voltage power supply path unit 410 is fixed to rear plate 501 of frame 500, and is covered by a rear cover (not shown) that constitutes the external appearance of image forming apparatus 100. High-voltage power supply path unit 410 has high-voltage path holding member 411 and duct 412 for exhausting air inside image forming apparatus 100 to the outside. High-voltage board unit 400 is fixed to high-voltage power supply path unit 410. Here, high-voltage board unit 400 is an example of a first unit.

[0027] The exhaust fan unit 450 includes a fan and a duct (not shown) that are connected to the duct 412 of the high-voltage power supply path unit 410 , and is fixed to the rear panel 501 .

[0028] The drum unit 600 includes a photosensitive drum 141, and is supported by a drum rail 510 provided on the frame 500. The drum unit 600 is guided along the drum rail 510 in the direction of the rotation axis of the photosensitive drum 141, and is detachable from the image forming apparatus 100.

[0029] Fig. 3(a) is an exploded perspective view of drum unit 600, high-voltage board unit 400, and high-voltage power supply path unit 410. Fig. 3(b) is an exploded perspective view of high-voltage board unit 400 as viewed from the front side of image forming apparatus 100. Fig. 3(c) is an exploded perspective view of high-voltage board unit 400 and high-voltage power supply path unit 410. Note that, for convenience, Fig. 3(a) only shows black drum unit 600Bk, but in reality, similar drum units for yellow Y, magenta M, and cyan C are also arranged in parallel in the direction of arrow X.

[0030] The high-voltage board unit 400 has a charging high-voltage board 402 which is a board for supplying high voltage to the drum unit 600, a developing high-voltage board 403 which is a board for supplying high voltage to the developing device 143 (Figure 1) which serves as a developing unit, a case 401 which holds the charging high-voltage board 402 and the developing high-voltage board 403, and a stopper 404 which prevents the boards from coming off the case 401.

[0031] The high voltage power supply path unit 410 has a conductive path for supplying power from each high voltage board, and is provided with compression springs 420a-d as contacts for connection and conduction to the charging high voltage board 402, and compression springs 421a-d as contacts for connection and conduction to the drum units 600Bk, C, M, and Y. The compression springs 420a-d and 421a-d are connected to each other by solder-plated soft copper wire (hereinafter referred to as jumper wire), thereby enabling electrical conduction. The connection configuration between the compression springs 420a-d, 421a-d, and the jumper wires 413a-d will be described in detail later.

[0032] Furthermore, the high voltage power supply path unit 410 is provided with compression springs 422a-d as contacts electrically connected to the development high voltage board 403, and compression springs 423a-d as contacts electrically connected to the development devices 143Bk, C, M, and Y. The compression springs 422a-d and the compression springs 423a-d are connected (conductive) to each other by jumper wires 414a-d, respectively.

[0033] As shown in Figures 3(b) and (c), the high-voltage board unit 400 is provided with contact leaf springs 405a-d that contact contacts 402a-d (Figure 4) provided on the charging high-voltage board 402 and that contact compression springs 420a-d, which are contacts of the high-voltage power supply path unit 410, and contact leaf springs 406a-d that contact contacts (not shown) provided on the developing high-voltage board 403 and that contact compression springs 422a-d, which are contacts of the high-voltage power supply path unit 410.

[0034] The contact leaf springs 405a-d are connected to the drum units 600Bk, C, M, and Y, respectively, via the high-voltage power supply path unit 410, and the contact leaf springs 406a-d are connected to the paths to the developing devices 143Bk, C, M, and Y, respectively, via the high-voltage power supply path unit 410.

[0035] In this embodiment, contact leaf spring 405a is connected to the path of drum unit 600Bk, contact leaf spring 405b is connected to the path of drum unit 600C, contact leaf spring 405c is connected to the path of drum unit 600M, and contact leaf spring 405d is connected to the path of drum unit 600Y.

[0036] In addition, in this embodiment, contact leaf spring 406a is connected to the path of developing device 143Bk, contact leaf spring 406b is connected to the path of developing device 143C, contact leaf spring 406c is connected to the path of developing device 143M, and contact leaf spring 406d is connected to the path of developing device 143Y.

[0037] High voltage board unit 400 is fixed to high voltage power supply path unit 410 by fastening mounting surfaces 401a, 401b of case 401 with screws to tapped bosses 411a, 411b for screw fastening provided on high voltage power supply path unit 410. By fastening high voltage board unit 400 to high voltage power supply path unit 410 in this manner, contact leaf springs 405a-d and contact leaf springs 406a-d come into contact with compression springs 420a-d and compression springs 422a-d, respectively, and are in a connected state.

[0038] Next, a contact state between drum unit 600 and high-voltage power supply path unit 410 will be described. Note that the contact configuration between drum units 600Bk, C, M, and Y and high-voltage power supply path unit 410 is the same. Below, a contact state between black drum unit 600Bk and the contact point of high-voltage power supply path unit 410 will be described, and a description of drum units 600C, M, and Y will be omitted.

[0039] The drum unit 600 is detachable from the image forming apparatus 100 by being guided on the drum rail 510 along the front-rear direction of the image forming apparatus (Y direction in the figure), and when the drum unit 600 is located at the mounting position of the image forming apparatus 100, a contact 600a of the drum unit 600 comes into contact with a compression spring 421a which is a contact of the high-voltage power supply path unit 410. Here, the mounting position of the image forming apparatus 100 is a position where a coupling (not shown) provided in the drum unit 600 is connected to a coupling (not shown) provided in the image forming apparatus 100. The photosensitive drum 141 of the drum unit 600 rotates by receiving a driving force from a driving unit (not shown) of the image forming apparatus 100 via the coupling at the mounting position.

[0040] In this manner, when the drum unit 600 is in the mounting position, the contact 600a comes into contact with the compression spring 421a, supplying power to a charging roller (not shown) provided in the drum unit 600, and the photosensitive drum 141 is charged by this charging roller.

[0041] Next, the high voltage power supply path from the charging high voltage board 402 to the drum unit 600 will be described in detail. Fig. 4 is a perspective view showing only the power supply path from the charging high voltage board 402 to the drum unit 600. For convenience, Fig. 4 shows only the black drum unit 600Bk, but in reality, similar ones for yellow Y, magenta M, and cyan C are also lined up in parallel. The developing unit (developing device 143) is also not shown, but it is provided with a power supply path from the developing high voltage board 403 in the same way as the power supply path to this drum unit 600. Here, the drum unit 600 or the developing unit (developing device 143) is an example of the second unit.

[0042] As shown in FIG. 4, the charging high voltage board 402 is provided with jumper wires 402a to d. The jumper wire 402a is a contact on the charging high voltage board 402 that contacts the contact leaf spring 405a to supply power to the drum unit 600Bk. The jumper wire 402b is a contact on the charging high voltage board 402 that contacts the contact leaf spring 405b to supply power to the drum unit 600C. The jumper wire 402c is a contact on the charging high voltage board 402 that contacts the contact leaf spring 405c to supply power to the drum unit 600M. The jumper wire 402d is a contact on the charging high voltage board 402 that contacts the contact leaf spring 405d to supply power to the drum unit 600Y. The power supply paths of the jumper wires 402a to d of the charging high voltage board 402 and the drum units 600Bk, C, M, and Y are configured in substantially the same manner. Therefore, in the following, only the high voltage power supply path from the charging high voltage substrate 402 to the drum unit 600Bk will be described, and the high voltage power supply paths of the other drum units 600C, 600M, and 600Y and the developing devices 143Bk, 143C, 143M, and 143Y will not be described.

[0043] The high voltage generated by the charged high voltage board 402 is sent to a jumper wire 402a, which is a contact point provided on the board. A contact leaf spring 405a provided on the high voltage board unit 400 is in contact with the jumper wire 402a.

[0044] Then, contact leaf spring 405a comes into contact with compression spring 420a provided in high-voltage power supply path unit 410. Compression spring 420a comes into contact with one end side of jumper wire 413a held by high-voltage path holding member 411. The other end side of jumper wire 413a comes into contact with compression spring 421a, which is a drum-side contact provided in high-voltage power supply path unit 410.

[0045] A high voltage is supplied from the charging high voltage board 402 to the drum unit 600 by contacting a compression spring 421 a provided in the high voltage power supply path unit 410 with a contact point 600 a of the drum unit 600 .

[0046] As described above, in this embodiment, the boundaries between each unit are each compression springs, and the contact configuration utilizes a biasing force, so that stable conductivity can be ensured even if the positional relationship between the units is misaligned due to tolerances, etc.

[0047] Next, a detailed description will be given of the high voltage path configuration within high voltage power supply path unit 410. Fig. 5(a) is a diagram of the state in which the jumper wire is routed around high voltage path holding member 411 as viewed from the high voltage board unit 400 side, and Fig. 5(b) is a diagram as viewed from the drum unit 600 side.

[0048] The high voltage path holding member 411 is provided with cylindrical guides 415a-d which hold compression springs 420a-d which contact the contact leaf springs 405a-d of the high voltage board unit 400, and cylindrical guides 416a-d which hold compression springs 422a-d which contact the contact leaf springs 406a-d.

[0049] Near the cylindrical guides 415a-d, there are provided receiving surfaces 417a-d on which the compression springs 420 are seated, hooking portions 425a-d on which the jumper wires 413a-d are hooked, and bosses 426a-d on which the jumper wires 413a-d are wound, and at positions adjacent to the cylindrical guides 415a-d, there are provided openings 427a-d necessary for forming the hooking portions 425a-d for processing purposes. Here, the cylindrical guides 415a-d are an example of a spring restricting portion that restricts the movement of the compression springs 420a-d in a direction perpendicular to the axial direction (expansion / contraction direction or free length direction) of the compression springs 420a-d.

[0050] Further, provided near the cylindrical guides 416a-d are receiving surfaces 432a-d on which the compression spring 422 is seated, hooks 435a-d on which the jumper wires 414a-d are hooked, bosses 436a-d around which the jumper wires 414a-d are wound, and openings 437a-d.

[0051] The jumper wires 413a-d and jumper wires 414a-d are held by the high pressure path holding member 411 through different paths, but since the basic configuration is substantially the same, the jumper wires 413a and 414a will be described in detail below as an example, and the other jumper wires 413b-d and 414b-d will not be described. Here, the cylindrical guides 415a-d and 416a-d are an example of a spring restricting portion that restricts the movement of the compression springs 420a-d in a direction perpendicular to the axial direction (expansion / contraction direction or free length direction) of the compression springs 420a-d and 422a-d.

[0052] 5(a), jumper wire 413a, with its end wound around boss 426a and hooked on hook portion 425a, crosses inside cylindrical guide 415a and is wired to the surface of high-pressure path holding member 411 facing the drum unit 600a side. Jumper wire 414a, with its end wound around boss 436a and hooked on hook portion 435a, crosses inside cylindrical guide 416a and is wired to the surface of high-pressure path holding member 411 facing developing device 143.

[0053] 5(b), jumper wire 413a is wired so as to cross cylindrical portion 428a along the rib shape of high-pressure path holding member 411 on the surface of high-pressure path holding member 411 facing the drum unit. Jumper wire 414a is wired so as to cross cylindrical portion 429a along the rib shape of high-pressure path holding member 411 on the surface of high-pressure path holding member 411 facing the drum unit.

[0054] 6A and 6B are diagrams showing the compression springs 421a and 423a attached to the high pressure path holding member 411, in which (a) is an enlarged perspective view of the vicinity of the compression springs 421a and 423a, and (b) is an overall perspective view of the high pressure path holding member 411. FIG.

[0055] 6(a), the compression spring 421a is attached to the inside of the cylindrical portion 428a so as to contact the jumper wire 413a passing through the inside of the cylindrical portion 428a. Also, the compression spring 423a is attached to the inside of the cylindrical portion 429a so as to contact the jumper wire 414a passing through the inside of the cylindrical portion 429a.

[0056] The compression spring 421a has an arm 421aa protruding radially outward from the cylindrical portion of the spring. Similarly, the compression spring 423a has an arm 423aa protruding radially outward from the cylindrical portion of the spring. In addition, the compression springs 421a-d and 423a-d are respectively fitted with insulator caps 440a-d and 441a-d to prevent leakage to the frame 500 of the image forming apparatus 100. The cap 440a is attached so as to hold down the arm 421aa of the compression spring 421a shown in FIG. 6(a), and the cap 441a is attached so as to hold down the arm 423aa of the compression spring 423a shown in FIG. 6(a), thereby preventing the compression springs 421a and 423a from falling off the high pressure path holding member 411. The caps 440b-d and 441b-d are also attached so as to hold down the arms of the compression springs. The caps 423a and 424a have openings. The ends of the compression springs 421a and 423a opposite to the arm portions 421aa and 423aa in the extension / contraction direction (free length direction) are exposed from the openings of the caps 423a and 424a, respectively, and can come into contact with a contact 600a of the drum unit 600 or a contact of the developing device 143.

[0057] Next, the holding structure of the compression spring in the cylindrical guide 415 of the high pressure path holding member 411 will be described. First, as a comparative example, a holding structure for holding the compression spring 480 in the cylindrical guide 415 of the conventional high pressure path holding member 411x will be described. FIG. 7 shows a conventional holding structure for the compression spring as a comparative example, where (a) is a perspective view of the holding structure for the conventional compression spring 480, (b) is a cross-sectional view seen from the direction A in FIG. 7(a), and (c) is a diagram showing a state in which the compression spring 480 is pulled in a direction away from the receiving surface 417x. Note that the jumper wire 413 is omitted from FIG. 7(c) for convenience.

[0058] 7(a) and (b), the conventional compression spring 480 restricts movement in a direction parallel to the receiving surface 417x (radial direction of the compression spring 480) by the cylindrical guide 415x, and restricts vertical movement of the receiving surface 417x of the compression spring 480 (the direction of expansion and contraction of the compression spring 480, the direction of the free length of the compression spring 480) by an arm portion 480a provided to protrude radially outward from the cylindrical guide 415x entering under a hook portion 425x. In this way, the conventional configuration was such that the jumper wire 413x wired inside the cylindrical guide 415x and the compression spring 480 are brought into contact with each other by holding the arm portion 480a of the compression spring 480 by hooking it on the hook portion 425x.

[0059] However, as shown in FIG. 7(c), when the compression spring 480 is subjected to a force that pulls it in the vertical direction of the receiving surface 417x, the winding (480b) of the spring cylindrical part is elastically deformed as shown in FIG. 7(c), the arm part 480a becomes inclined with respect to the hook part 425x, and the restraining force is reduced, so that the compression spring 480 may fall off the cylindrical guide 415x. In addition, when the compression spring 480 rotates, the engagement between the arm part 480a and the hook part 425x is released, so that the compression spring 480 may fall off the cylindrical guide 415x. In the case where the compression spring 480 and the jumper wire 413x are configured as separate members as in this conventional example, if the compression spring 480 falls off the cylindrical guide 415x, there is a risk that the compression spring 480 and the jumper wire 413x will not come into contact with each other, and electrical connection (continuity) will not be established.

[0060] Therefore, in this embodiment, a compression spring 420 that can prevent the compression spring and the jumper wire from coming into contact with each other even when the compression spring and the jumper wire are configured as separate parts will be described.

[0061] FIG. 8 is a diagram showing a holding structure for a compression spring 420d in this embodiment, where (a) is a perspective view of the vicinity of the compression spring 420, and (b) is a cross-sectional view seen from direction A in (a).

[0062] Here, this embodiment will be described using compression spring 420d as an example, but the above-mentioned compression springs 420a-c and compression springs 422a-d also have a similar shape to compression spring 420d, and engage with high pressure path holding member 411 with a similar configuration.

[0063] 8(a), the jumper wire 413d passes through the inside of the cylindrical guide 415d, is hooked on the hook portion 425, and is wound around the boss 426d. The compression spring 420d is attached to the inside of the cylindrical guide 415d, and thus the movement of the compression spring 420d in the planar direction of the receiving surface 417d (the radial direction of the compression spring 420d) is restricted by the cylindrical guide 415d.

[0064] 8, the compression spring 420d of this embodiment has an arm 420db that protrudes radially outward from a spring cylindrical portion 420da wound in a coil shape. The arm 420db has a first portion db1, a second portion db2, a third portion db3, a fourth portion db4, a first bent portion dbm1, a second bent portion dbm2, and a third bent portion dbm3.

[0065] The first portion db1 of the arm portion 420db is a portion extending from one end of the spring cylindrical portion 420da in the free length direction. The second portion db2 of the arm portion 420db is a portion bent at a first bent portion dbm1 in a direction approaching the spring cylindrical portion 420da with respect to the first portion db1 so that the angle between the first portion db1 and the arm portion 420db is an acute angle. The third portion db3 of the arm portion 420db is a portion bent at a second bent portion dbm2 in a direction away from the spring cylindrical portion 420da with respect to the second portion db2 so that the angle between the second portion db2 and the arm portion 420db is an approximately right angle. The fourth portion db4 of the arm portion 420db is a portion bent at a third bent portion dbm3 in the direction of the arrow Y with respect to the third portion db3 so that the angle between the fourth portion db4 and the third portion db3 is an approximately right angle. In this embodiment, a substantially right angle does not only indicate 90°, but also includes the range of tolerances during manufacturing of parts, and in this embodiment, a substantially right angle is defined as an angle between 85° and 95°.

[0066] The arm 420db configured in this manner sandwiches the receiving surface 417d between the first portion db1 and the second portion db2. This makes it possible to restrict the movement of the compression spring 420d in the direction of the arrow Y (the free length direction of the compression spring 420d, which is the direction of expansion and contraction) relative to the receiving surface 417d. Therefore, even if the compression spring 420d rotates radially relative to the cylindrical guide 415d or is pulled in the direction of the arrow Y, the arm 420db engages with the receiving surface 417, and thus it is possible to prevent the compression spring 420d from falling off the cylindrical portion of the high pressure path holding member 411.

[0067] Next, a method of attaching the compression spring 420 of this embodiment to the high pressure path holding member 411 will be described with reference to Fig. 9. Fig. 9(a) is a perspective view of the vicinity of the compression spring 420, Fig. 9(b) is a cross-sectional view taken along line AA in Fig. 9(a), and Fig. 9(c) is a view in which the compression spring 420 has been moved even closer to the attachment position from the state in Fig. 9(b). Note that the jumper wire 413 has been omitted from Figs. 9(b) and (c) for the sake of convenience.

[0068] The compression spring 420d is aligned so that the spring cylindrical portion 420da fits into the cylindrical guide 415d of the high pressure path holding member 411 with the jumper wire 413d wired thereto, and is pressed toward the receiving surface 417d in the direction opposite to the direction of the arrow Y. The movement of the compression spring 420d in a direction parallel to the receiving surface 417d is restricted by the cylindrical guide 415d.

[0069] When the compression spring 420d is further pressed in, the third portion db3 of the arm portion 420db of the compression spring 420d comes into contact with the ridgeline between the receiving surface 417d and the end surface 418d of the receiving surface 417d.

[0070] Here, since the third bent portion dbm3 is present between the third portion db3 and the fourth portion db4 of the arm portion 420db, the tip of the arm is prevented from directly hitting and getting caught on the receiving surface 417, thereby preventing a decrease in the ease of assembly.

[0071] Then, when compression spring 420d is further pressed toward receiving surface 417d from the state shown in FIG. 9(b), the second portion db2 of arm portion 420db opens due to elastic deformation so that the angle of first bent portion dbm1 relative to the first portion db1 becomes larger, and the second bent portion dbm2 climbs over the ridge between receiving surface 417d and end face 418d of receiving surface 417d and moves along end face 418 in the opposite direction to the arrow Y (FIG. 9c).

[0072] Here, because there is a second bent portion dbm2 at the end of the arm portion 420db that forms the third portion db3 extending in a direction away from the axis of the spring cylindrical portion 420da, the arm portion naturally spreads out along the slope of the third portion db3 when the spring is pressed in. This improves the ease of assembly when attaching the compression spring 420 to the cylindrical guide 415 of the high pressure path holding member 411.

[0073] If the compression spring 420d continues to be pressed in this state, the second bent portion dbm2 between the second portion db2 and the third portion db3 will overcome the end face 418d, resulting in the state shown in Fig. 8(b). At this time, when the second bent portion dbm2 overcomes the end face 418d, the first bent portion dbm1 that had been elastically deformed returns to its original angle, and the positions of the first portion db1 and the second portion db2 return to their original positional relationship, so that the second bent portion dbm2 is located at a position closer to the axis of the spring cylindrical portion 420da than the end face 418 on the back surface 419d side of the receiving surface 417d (Fig. 8(b)).

[0074] In this way, the second part db2 of the arm 420db hooks onto the back surface 419d, and the first part db1 and the second part db2 of the arm 420db clamp the receiving surface 417d, thereby restricting the axial movement of the spring cylindrical part 420da of the compression spring 420d relative to the receiving surface 417d of the compression spring 420d (the expansion / contraction direction and free length direction of the spring cylindrical part 420da).

[0075] With the configuration described above, even when the spring cylindrical portion 420da of the compression spring 420d is pulled, the first portion db1 and the second portion db2 of the arm portion 420db sandwich the receiving surface 417d, and the second bent portion dbm2 catches on the back surface 419d of the receiving surface 417d at a position closer to the axis of the spring cylindrical portion 420da than the end face 418d. This makes it possible to prevent the compression spring 420d from falling off the high pressure path retaining member 411 more effectively than in the conventional example shown in Figure 7.

[0076] In addition, when the compression spring 420d is attached, the jumper wire 413d located on the receiving surface 417d is pressed down by the spring cylindrical portion 420da of the compression spring 420d, and the arm portion 420db further clamps the receiving surface 417d to fix the compression spring 420d.In addition, when the high-voltage board unit 400 is attached to the high-voltage path holding member 411, the compression spring 420d is biased toward the jumper wire 413d, thereby ensuring contact between the compression spring 420d and the jumper wire 413d and ensuring conductivity.

[0077] Here, compression spring 420d has been described as an example of this embodiment, but compression springs 420a-c and compression springs 422a-d described above also have the same shape. Therefore, similar to the above description, compression springs 420a-c and compression springs 422a-d are also configured to be prevented from falling off cylindrical guides 415b-d or cylindrical portions 416a-d of high pressure path holding member 411.

[0078] As described above, by configuring the jumper wires 413a-d and the compression springs 420a-d as separate parts, it is possible to improve the ease of assembly when attaching the contact member to the high pressure path holding member 411. Furthermore, by making the shape of the compression springs 420a-d as shown in Figs. 8 and 9 described above, it is possible to prevent the compression springs 420a-d from falling off the cylindrical guides 415a-d of the high pressure path holding member 411 even if the compression springs 420a-d are unintentionally touched during the assembly or maintenance of each unit. This improves the ease of assembly or maintenance of each unit.

[0079] <Second embodiment> In the first embodiment described above, a configuration was described in which the outer diameter of the spring is supported by cylindrical guide 415 to regulate the direction parallel to the receiving surface of compression spring 420 (the direction perpendicular to the direction of expansion and contraction of the compression spring, i.e., the radial direction of the compression spring). However, the compression spring may be supported by another configuration.

[0080] 10A and 10B are perspective views showing another support structure for supporting the compression spring 420, in which (a) shows the state in which the compression spring 420 has been removed, and (b) shows the state in which the compression spring 420 has been attached.

[0081] 10(a) and 10(b), in this embodiment, a cross-shaped boss 490 is provided on the receiving surface 417 of the high pressure path holding member 411. The compression spring 420 of this embodiment has a similar configuration to the compression spring 420d described in Fig. 8. Here, regarding the configuration of the compression spring 420, the spring cylindrical portion is denoted as 420ga, and the arm portion extending radially outward from the spring cylindrical portion 420ga ​​is denoted as 420gb.

[0082] In FIG. 10, by fitting the cylindrical portion 420ga ​​of the compression spring 420 into the boss 490, it is possible to restrict the movement of the compression spring 420 in a direction perpendicular to the expansion / contraction direction (and free length direction) of the compression spring 420. Furthermore, by providing an arm portion 420gb having the same shape as the arm portion of the first embodiment, it is possible to restrict the movement of the compression spring 420 in the expansion / contraction direction (and free length direction). This makes it possible to prevent the compression spring 420 from falling off the high pressure path holding member 411. This makes it possible to improve the workability during assembly and maintenance of each unit.

[0083] <Third embodiment> In addition, in the first embodiment, the first bent portion dbm1 is formed so that the angle between the first portion db1 and the second portion db2 of the arm portion 420db of the compression spring 420 is an acute angle, but other shapes may be used.

[0084] Fig. 11 shows a cross-sectional view of a compression spring 420f in another embodiment. The compression spring 420f shown in Fig. 11 has a spring cylindrical portion 420fa and an arm portion 420fb extending from the spring cylindrical portion 420fa. The shape of the arm portion 420fb here is different from that of the compression spring 420d of the first embodiment described in Fig. 8, and has one more bent portion than the arm portion 420db shown in Fig. 8.

[0085] As shown in FIG. 11, the arm portion 420fb of the compression spring 420f in this embodiment has a first portion fb1, a second portion fb2, a third portion fb3, a fourth portion fb4, a fifth portion fb5, a first bent portion fbm1, a second bent portion fbm2, a third bent portion fbm3, and a fourth bent portion fbm4.

[0086] The first portion fb1 of the arm portion 420fb is a portion extending from one end of the spring cylindrical portion 420fa in the free length direction. The second portion fb2 of the arm portion 420fb is a portion bent at a first bent portion fbm1 with respect to the first portion fb1 so that the angle between the arm portion 420fb and the first portion fb1 is approximately a right angle. The third portion fb3 of the arm portion 420fb is a portion bent at a second bent portion fbm2 with respect to the second portion fb2 in a direction approaching the spring cylindrical portion 420fa so that the angle between the arm portion 420fb and the second portion fb2 is an obtuse angle. The fourth portion fb4 of the arm portion 420fb is a portion bent at a third bent portion fbm2 with respect to the third portion fb3 in a direction away from the spring cylindrical portion 420fa so that the angle between the arm portion 420fb and the third portion fb3 is approximately a right angle. The fifth portion fb5 of the arm portion 420fb is bent in the direction of the arrow Y at a fourth bent portion dbm4 relative to the fourth portion fb4 so that the angle between the fifth portion fb5 and the fourth portion fb4 is approximately a right angle.

[0087] The arm 420fb thus configured sandwiches the receiving surface 417 between the first portion fb1 and the third portion fb3. This makes it possible to restrict movement of the compression spring 420f in a direction perpendicular to the horizontal direction (the free length direction of the compression spring 420f, which is the expansion / contraction direction) relative to the receiving surface 417. Therefore, even if the compression spring 420f rotates radially relative to the boss 490 or is pulled in the release direction, the arm 420fb engages with the receiving surface 417, and therefore it is possible to prevent the compression spring 420f from falling off the high pressure path holding member 411.

[0088] <Other embodiments> In the above-described embodiment, the compression spring 420 that serves as a contact point between the high-voltage board unit 400 and the high-voltage power supply path unit 410 has been described as an example, but a configuration in which the compression springs 421 and 423 that serve as contact points between the high-voltage power supply path unit 410 and a removable unit such as the drum unit 600 or the developing device 143 have arms of a similar shape may also be used. Also, in the above-described embodiment, the high-voltage power supply path has been described as an example, but the present invention is not limited to the above, and the above-described compression spring may also be used as a contact point for earthing. [Explanation of symbols]

[0089] 100 Image forming device 400 High voltage board unit 410 High voltage power supply line unit 411 High pressure path retaining member 413 Jumper Wire 417 Receiving surface 415 Cylinder Guide 420 Compression Spring 600 Drum Unit

Claims

1. A power supply unit that supplies power; a process unit that performs a part of an image forming process using the power supplied from the power supply unit; a power supply path unit that provides a conductive path from the power supply unit to the process unit, The power supply path unit includes: a coil spring that constitutes a contact point with the power supply unit or the process unit as a part of the conductive path; a holding member for holding the coil spring, The coil spring is A coil portion; an arm portion provided integrally with the coil portion and extending outward from one end of the coil portion along a radial direction of the coil portion, the holding member has a restricting portion that restricts movement of the coil spring in the radial direction, The arm portion of the coil spring has a hook portion that engages with a part of the holding member. the holding member includes a plate portion in contact with the one end of the coil portion and having a surface extending in the radial direction of the coil portion, The arm portion is a first portion extending from the one end of the coil portion outward relative to the coil portion in the radial direction; a second portion extending from an end of the first portion opposite the coil portion toward the coil portion in the radial direction via a first bent portion; a third portion extending from an end of the second portion opposite to the first portion via a second bent portion so as to move away from the coil portion toward the outside in the radial direction, the first bent portion forms an acute angle, and the first portion and the second portion sandwich the plate portion in the extension / contraction direction of the coil portion, so that the first portion and the second portion form the hook portion, The third portion extends beyond an end of the plate portion in the radial direction.

1. An image forming apparatus comprising:

2. The end of the coil portion opposite to the end where the arm portion is provided is the contact point.

2. The image forming apparatus according to claim 1,

3. the power supply path unit further includes a conductive member that constitutes another part of the conductive path together with the coil spring, The one end of the coil portion of the coil spring is in contact with the conductive member.

2. The image forming apparatus according to claim 1,

4. The conductive path includes a solder-plated soft copper wire.

4. The image forming apparatus according to claim 3.

5. The process unit includes a charging unit that charges a photosensitive drum.

2. The image forming apparatus according to claim 1,

6. The process unit includes a developing unit that develops an electrostatic latent image formed on the photosensitive drum with toner.

2. The image forming apparatus according to claim 1,

Images