Image forming apparatus

Abstract

To provide a device that is less prone to sealing failures even when the thickness of the sealing member that fills the gap between the fixing unit and the heating unit is large. [Solution] The fixing unit 5b has an opposing surface 55c that faces a part of the heating unit 5a and is formed along a first direction. The heating unit 5a has an adhesive surface 54c and an elastic sealing member 57. The adhesive surface 54c faces the opposing surface 55c and is formed along the first direction. The sealing member 57 is arranged with the first direction as its longitudinal direction, is bonded to the adhesive surface 54c, and is sandwiched between the opposing surface 55c and the adhesive surface 54c when the heating unit 5a is in close proximity. The sealing member 57 has a laminated structure comprising a first foam member 571 bonded to the adhesive surface 54c, a resin sheet 572 bonded to the first foam member 571, and a second foam member 573 bonded to the resin sheet 572.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus including a fixing device divided into a fixing unit and a heating unit.

Background Art

[0002] An electrophotographic image forming apparatus transfers a toner image from an image carrier to a sheet and fixes the toner image to the sheet by a fixing device.

[0003] The fixing device may be divided into a heating unit having a heater and a fixing unit having a fixing member and a pressure roller. The heater heats the fixing member, and the pressure roller biases the sheet on which the toner image is transferred toward the fixing member.

[0004] Also, it is known that the fixing device includes a mechanism for moving the heating unit between a proximity position along the fixing unit and a retracted position farther from the fixing unit than the proximity position (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the image forming apparatus, there is a risk that scattered toner may enter between the fixing unit and the heating unit. The entry of the scattered toner between the fixing unit and the heating unit may cause noise images on the sheet.

[0007] Therefore, it is conceivable that a sealing member be provided to fill the gap between the fixing unit and the heating unit. However, there are cases where the gap between the fixing unit and the heating unit cannot be sufficiently narrowed. In this case, it is necessary to use a sealing member with a larger thickness.

[0008] If the thickness of the sealing member is large, the sealing member may bend when the heating unit is brought close to the fixing unit, potentially causing a sealing failure.

[0009] The object of the present invention is to provide an image forming apparatus that is less prone to sealing defects even when the thickness of the sealing member that fills the gap between the fixing unit and the heating unit is large. [Means for solving the problem]

[0010] An image forming apparatus according to one aspect of the present invention comprises a transfer apparatus, a fixing apparatus, and a unit moving mechanism for moving a part of the fixing apparatus. The transfer apparatus transfers a toner image formed on an image carrier to a sheet. The fixing apparatus fixes the toner image on the sheet by heating and pressurizing the toner image on the sheet. The fixing apparatus comprises a fixing unit and a heating unit. The fixing unit has a fixing member to be heated and a pressurizing member that biases the sheet on which the toner image is formed toward the fixing member, and is arranged with the first direction as the longitudinal direction. The heating unit has a heater for heating the fixing member and is arranged with the first direction as the longitudinal direction, adjacent to a second direction that intersects the first direction with respect to the fixing unit. The unit moving mechanism is a mechanism for moving the heating unit between a proximity position along the fixing unit and a retracted position further away from the fixing unit than the proximity position. The fixing unit has a facing surface that faces a part of the heating unit and is formed along the first direction. The heating unit has an adhesive surface and an elastic sealing member. The adhesive surface is formed facing the opposing surface and along the first direction. The sealing member is arranged with the first direction as its longitudinal direction, is bonded to the adhesive surface, and is sandwiched between the opposing surface and the adhesive surface when the heating unit is in the proximity position. The sealing member has a laminated structure comprising a first foamed member bonded to the adhesive surface, a resin sheet bonded to the first foamed member, and a second foamed member bonded to the resin sheet. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an image forming apparatus in which sealing defects are less likely to occur even when the thickness of the sealing member that fills the gap between the fixing unit and the heating unit is large. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a configuration diagram of an image forming apparatus according to an embodiment. [Figure 2]Figure 2 is a diagram showing a part of the configuration of the fixing device in the image forming apparatus according to the embodiment. [Figure 3] Figure 3 is a front view of the fixing device in close proximity in the image forming apparatus according to the embodiment. [Figure 4] Figure 4 is a front view of the fixing device in the separated state in the image forming apparatus according to the embodiment. [Figure 5] Figure 5 is a plan view of the fixing device and unit movement mechanism in close proximity in the image forming apparatus according to the embodiment. [Figure 6] Figure 6 is a plan view of the fixing device and unit movement mechanism in the separated state in the image forming apparatus according to the embodiment. [Figure 7] Figure 7 is a plan view of the connecting mechanism of the connecting member when the unit moving mechanism in the image forming apparatus according to the embodiment is in a biased state. [Figure 8] Figure 8 is a plan view of the unit connecting mechanism of the image forming apparatus according to the embodiment when the unit moving mechanism is in the pulled-back position. [Figure 9] Figure 9 is a plan cross-sectional view of the peripheral portion of the sealing member in the image forming apparatus according to the embodiment. [Figure 10] Figure 10 is a perspective view of a sealing member in an image forming apparatus according to an embodiment. [Figure 11] Figure 11 is a plan cross-sectional view of the peripheral portion of a modified sealing member applicable to an image forming apparatus according to the embodiment. [Figure 12] Figure 12 is a front view of a modified fixing device applicable to an image forming apparatus according to the embodiment. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0014] [Configuration of the image forming apparatus 10] The image forming apparatus 10 according to the embodiment executes print processing by an electrophotographic method. The print processing is a process of forming an image on a sheet 900.

[0015] As shown in FIG. 1, the image forming apparatus 10 includes a sheet storage unit 2, a sheet conveyance device 3, and a print device 4. The sheet conveyance device 3 and the print device 4 are housed in a main body 1 which is a housing. The main body 1 includes a main body frame 1x forming the skeleton of the main body 1 and exterior members attached to the main body frame 1x.

[0016] The sheet conveyance device 3 includes a sheet feeding device 30 and a plurality of sets of conveyance roller pairs 31. The sheet feeding device 30 feeds the sheets 900 in the sheet storage unit 2 one by one into a conveyance path 300. The conveyance path 300 is a passage for the sheet 900.

[0017] The plurality of sets of conveyance roller pairs 31 convey the sheet 900 along the conveyance path 300. One set of the plurality of sets of conveyance roller pairs 31 discharges the sheet 900 with an image formed thereon from the conveyance path 300 onto a discharge tray 1a.

[0018] The print device 4 executes the print processing on the sheet 900 conveyed along the conveyance path 300. The image formed on the sheet 900 is a toner image.

[0019] The print device 4 includes an optical scanning unit 40, one or more image forming units 4x, a transfer device 45, and a fixing device 5. The image forming unit 4x includes a photoreceptor 41, a charging device 42, a developing device 43, and a drum cleaning device 44.

[0020] The charging device 42 charges the surface of the photoreceptor 41. The optical scanning unit 4 is a scanning beam light on the surface of the charged photoreceptor 41. Thereby, the optical scanning unit 40 forms an electrostatic latent image on the surface of the photoreceptor 41.

[0021] The developing device 43 develops the electrostatic latent image into a toner image by supplying toner to the surface of the photoreceptor 41. The transfer device 45 transfers the toner image formed on the surface of the photoreceptor 41 to the sheet 900.

[0022] The transfer device 45 transfers the toner image formed on the photoreceptor 41 to the sheet 900. The transfer device 45 transfers the toner image to the sheet 900 at the transfer position P1 in the transport path 300. The photoreceptor 41 is an example of an image carrier that carries and rotates the toner image.

[0023] In this embodiment, the printing apparatus 4 is a tandem-type color printing apparatus equipped with multiple image forming units 4x. The transfer apparatus 45 includes an intermediate transfer belt 450, multiple primary transfer devices 451, a secondary transfer device 452, and a belt cleaning device 453.

[0024] In the example shown in Figure 1, the printing device 4 comprises four image forming units 4x corresponding to four toner colors: yellow, magenta, cyan, and black. The transfer device 45 comprises four primary transfer units 451 corresponding to the four image forming units 4x.

[0025] The intermediate transfer belt 450 is rotatably supported by a plurality of support rollers 454. One of the support rollers 454 is rotated by a belt drive device (not shown), thereby causing the intermediate transfer belt 450 to rotate.

[0026] Each primary transfer device 451 transfers the toner image formed on the surface of the photoreceptor 41 in each image forming unit 4x to the surface of the intermediate transfer belt 450. As a result, a toner image formed by combining the four toner images is formed on the surface of the intermediate transfer belt 450.

[0027] The intermediate transfer belt 450 rotates while carrying the toner image. The secondary transfer device 452 transfers the toner image formed on the surface of the intermediate transfer belt 450 to the sheet 900 at the transfer position P1.

[0028] The drum cleaning device 44 removes primary waste toner from the surface of the photoreceptor 41. The primary waste toner is the toner remaining on the surface of the photoreceptor 41 that has passed through the primary transfer device 451.

[0029] The belt cleaning device 453 removes secondary waste toner from the surface of the intermediate transfer belt 450. The secondary waste toner is the toner remaining on the surface of the intermediate transfer belt 450 that has passed through the secondary transfer device 452.

[0030] The fixing device 5 heats and pressurizes the toner image on the sheet 900 at the fixing position P2 in the transport path 300. This fixes the toner image on the sheet 900. The fixing position P2 is located downstream of the transfer position P1 in the sheet transport direction.

[0031] As shown in Figure 2, the fixing device 5 includes a heater 51, a fixing belt 52, a fixing roller 520, a pressure roller 53, and a sheet separating member 5200.

[0032] The fixing belt 52 is a flexible cylindrical member that encloses the fixing roller 520. The fixing belt 52 is heated by the heater 51.

[0033] The fixing roller 520 is a cylindrical member that supports the fixing belt 52 from its inside. The fixing roller 520 is rotatably supported. The fixing belt 52 is rotatable together with the fixing roller 520.

[0034] The fixing belt 52 has a conductive base material, an elastic layer formed on the outer periphery of the base material, and a release layer formed on the outer periphery of the elastic layer.

[0035] The heater 51 is positioned opposite the outer circumferential surface of the fixing belt 52 and heats the fixing belt 52. In this embodiment, the heater 51 is an electromagnetic induction heating device. The heater 51 mainly heats the base material of the fixing belt 52 by electromagnetic induction. For example, a halogen heater may be used as the heater 51.

[0036] The pressure roller 53 is rotatably supported. The pressure roller 53 is driven and rotated by a drive device (not shown). The fixing belt 52 and fixing roller 520 rotate in conjunction with the pressure roller 53.

[0037] The fixing belt 52 heats the toner image formed on the sheet 900. The pressure roller 53 pressurizes the sheet 900 toward the sheet 900 by biasing the sheet 900 toward the fixing belt 52.

[0038] The fixing belt 52 is an example of a fixing member that is heated by the heater 51. The pressure roller 53 is an example of a pressure member that biases the sheet 900 onto the fixing belt 52.

[0039] The sheet separation member 5200 separates the sheet 900 from the fixing belt 52 when the sheet 900 adheres to the fixing belt 52.

[0040] In this embodiment, the fixing device 5 is divided into a heating unit 5a and a fixing unit 5b (see Figures 3 and 4). The heating unit 5a is arranged within the main body 1 along the first direction D1. The fixing unit 5b is also arranged within the main body 1 along the first direction D1.

[0041] In other words, the heating unit 5a and the fixing unit 5b are arranged with the first direction D1 as their longitudinal direction.

[0042] The heating unit 5a is positioned adjacent to the second direction D2 relative to the fixing unit 5b. That is, the second direction D2 is the alignment direction of the heating unit 5a and the fixing unit 5b. The second direction D2 is perpendicular to the first direction D1.

[0043] In the following description, one side of the second direction D2 will be referred to as the first side D21, and the other side of the second direction D2 will be referred to as the second side D22 (see Figures 3-10). The heating unit 5a is positioned on the first side D21 relative to the fixing unit 5b (see Figures 3-6).

[0044] The heating unit 5a includes a heater 51 and a first support 54. The fixing unit 5b includes a fixing belt 52, a fixing roller 520, a pressure roller 53, and a second support 55.

[0045] The first support member 54 is a member that supports the heater 51. The second support member 55 is a member that supports the fixing belt 52, the fixing roller 520, and the pressure roller 53. The fixing belt 52 is supported by the second support member 55 via the fixing roller 520.

[0046] The main frame 1x includes multiple metal pipes joined together, for example, by welding. The heating unit 5a and the fixing unit 5b are supported by the main frame 1x.

[0047] The multiple metal pipes in the main frame 1x include a restricting portion 11 and a lower support portion 12 (see Figures 3-6).

[0048] In this embodiment, the restricting section 11 is formed extending in the vertical direction D3 and consists of two support pipes spaced apart in the first direction D1 (see Figures 3 and 4). The vertical direction D3 is the up and down direction.

[0049] The lower support section 12 is formed below the heating unit 5a and the fixing unit 5b, extending in the second direction D2, and consists of two beam pipes spaced apart in the first direction D1 (see Figures 5 and 6).

[0050] The heating unit 5a and the fixing unit 5b are each placed on the lower support portion 12 with their longitudinal directions aligned with the first direction D1 (see Figures 3 and 4).

[0051] The heating unit 5a is movable along the second direction D2 on the lower support portion 12. Specifically, the heating unit 5a is movable between a close position along the fixing unit 5b and a retracted position further away from the fixing unit 5b towards the first side D21 than the close position. The fixing unit 5b is positioned between the heating unit 5a and the regulating portion 11 (see Figures 4 and 5).

[0052] When the heating unit 5a is in the retracted position, the fixing unit 5b can be pulled out from inside the main body 1 along the first direction D1 (see Figure 6).

[0053] The main body 1 has an exposed opening 101 that exposes the interior to the outside (see Figures 5 and 6). The fixing unit 5b is positioned inside the exposed opening 101 within the main body 1, along the first direction D1.

[0054] The exposed opening 101 is an opening that opens one end of the fixing unit 5b in the first direction D1 to the outside of the main body 1. The image forming apparatus 10 is equipped with a cover member 102 that can open and close the exposed opening 101 (see Figures 5 and 6).

[0055] The cover member 102 is rotatable around the first support shaft 102x between a closed position that closes the exposed opening 101 and an open position that opens the exposed opening 101. Figure 5 shows the cover member 102 and fixing device 5 in the closed position. Figure 6 shows the cover member 102 and fixing device 5 in the open position.

[0056] When the cover member 102 is in the closed position, it is held in that position by a locking mechanism (not shown). When the lock by the locking mechanism is released, the cover member 102 can rotate from the closed position to the open position.

[0057] When the heating unit 5a is in the retracted position and the cover member 102 is in the open position, the fixing unit 5b can be pulled out from the main body 1 through the exposed opening 101. In Figure 6, the pulling direction D11 is the direction in which the fixing unit 5b is pulled out from the main body 1.

[0058] The image forming apparatus 10 includes a unit movement mechanism 7 that moves the heating unit 5a between the proximity position and the retracted position (see Figures 5 and 6). The unit movement mechanism 7 is located on the first side D21 in the second direction D2 relative to the heating unit 5a.

[0059] Furthermore, the image forming apparatus 10 is equipped with one or more fans 6 that blow air toward the heating unit 5a (see Figures 1, 3 to 6). The fans 6 are located within the main body 1 on the first side D21 in the second direction D2 relative to the unit movement mechanism 7 (see Figures 3 to 6).

[0060] In this embodiment, the image forming apparatus 10 includes a pair of fans 6 arranged at intervals in the first direction D1 (see Figures 5 and 6).

[0061] The heating unit 5a includes a ventilation duct 540 that exchanges heat between the heater 51 and the cooling air by passing cooling air supplied from a pair of fans 6 through it (see Figures 3-6).

[0062] [Configuration of the unit movement mechanism 7 and ventilation duct 540] The cover member 102 is connected to the unit movement mechanism 7 and also serves as an operating member 103 that receives commands to operate the unit movement mechanism 7 (see Figures 5 and 6).

[0063] The cover member 102 is movable in a first or second operating direction by being operated. The cover member 102 is located at one end of the main body 1 in the first direction D1 (see Figures 7 and 8).

[0064] Hereinafter, the direction in which the cover member 102 moves from the open position to the closed position will be referred to as the first operating direction. Similarly, the direction in which the cover member 102 moves from the closed position to the open position will be referred to as the second operating direction.

[0065] The unit movement mechanism 7 moves the heating unit 5a along the second direction D2 in conjunction with the movement of the cover member 102.

[0066] The unit movement mechanism 7 moves the heating unit 5a from the retracted position to the close position in conjunction with the movement of the cover member 102 in the first operating direction (see Figure 5). On the other hand, the unit movement mechanism 7 also moves the heating unit 5a from the close position to the retracted position in conjunction with the movement of the cover member 102 in the second operating direction (see Figure 6).

[0067] The unit movement mechanism 7 comprises a unit connecting member 56 and a link mechanism 7x. The unit connecting member 56 is connected to the heating unit 5a. The link mechanism 7x transmits the movement of the cover member 102 to the unit connecting member 56.

[0068] The heating unit 5a further comprises a duct forming member 541 attached to the first side D21 surface of the first support 54 (see Figures 3-6). In this embodiment, the ventilation duct 540 is composed of the duct forming member 541 and the first support 54.

[0069] The ventilation duct 540 has a cavity 540a formed between the first support 54 and the duct forming member 541, a pair of inlet openings 540b communicating with the cavity 540a, and an outlet opening 540c communicating with the cavity 540a (see Figure 5). The pair of inlet openings 540b and outlet openings 540c are openings formed in the duct forming member 541.

[0070] The cavity 540a is formed along the first direction D1 (see Figure 5). That is, the cavity 540a is formed along the heater 51 with the first direction D1 as the longitudinal direction.

[0071] The pair of inlet openings 540b are positioned opposite the pair of fans 6. The pair of fans 6 and the pair of inlet openings 540b are each positioned on both sides of the first direction D1 relative to the unit connecting member 56.

[0072] The pair of fans 6 blow air toward the second side D22 in the second direction D2. The pair of inlet openings 540b open toward the first side D21 in the second direction D2 at positions corresponding to the pair of fans 6 in the first direction D1.

[0073] The outflow opening 540c is formed between a pair of inflow openings 540b in the first direction D1. In this embodiment, the outflow opening 540c opens to the first side D21 in the second direction D2.

[0074] The unit connecting member 56 is connected to the heating unit 5a at a position between a pair of inlet openings 540b in the first direction D1, with a gap 5600 between it and the outlet opening 540c (see Figure 7). The outlet opening 540c opens toward the gap 5600.

[0075] In this embodiment, the unit connecting member 56 is connected to the duct forming member 541 of the heating unit 5a by a connecting mechanism 560 (see Figures 5, 7, and 8).

[0076] The cooling air, delivered by the pair of fans 6, flows into the cavity 540a through the pair of inlet openings 540b. Furthermore, the cooling air efficiently cools the heating unit 5a as it flows through the cavity 540a from both ends in the first direction D1 towards the center of the first direction D1.

[0077] Furthermore, after cooling the heating unit 5a, the cooling air flows out from the cavity 540a through the outlet opening 540c into the gap 5600. The cooling air then flows out of the gap 5600 mainly along the vertical direction D3.

[0078] The link mechanism 7x comprises a guide member 70, a movable member 71, a first biasing member 72, and a first directional movement mechanism 73.

[0079] The first biasing member 72 biases the heating unit 5a toward the first side D21. Specifically, the first biasing member 72 is one or more elastic members that bias the heating unit 5a toward the first side D21. For example, the elastic member is a coil spring or a leaf spring.

[0080] In the example shown in Figures 5 and 6, the first biasing member 72 consists of two tension springs that elastically bias the heating unit 5a toward the first side D21.

[0081] The unit connecting member 56 has an inclined surface 7a. The inclined surface 7a is provided on the heating unit 5a facing the first side D21. The inclined surface 7a is a surface that is inclined from the second side D22 to the first side D21 with respect to the first direction D1. In this embodiment, the inclined surface 7a is provided at two locations spaced apart in the first direction D1 (see Figures 5 and 6).

[0082] The movable member 71 is supported so as to be movable along a first direction D1. The guide member 70 guides the movable member 71 along the first direction D1. For example, the guide member 70 is supported by the main frame 1x.

[0083] The movable member 71 has one or more rotatably supported rollers 71a (see Figures 7-9). The rollers 71a are provided at locations on the movable member 71 corresponding to the inclined surface 7a. In this embodiment, the rollers 71a are provided at two locations spaced apart in the first direction D1 (see Figures 7-9). The rollers 71a roll in contact with the inclined surface 7a.

[0084] The first direction movement mechanism 73 moves the movable member 71 along the first direction D1 in conjunction with the movement of the cover member 102. In this embodiment, the first direction movement mechanism 73 is a mechanism that converts the rotation of the cover member 102 into linear motion along the first direction D1.

[0085] The first directional movement mechanism 73 comprises a first link member 731, a second link member 732, and a third link member 733 (see Figures 7 and 8).

[0086] One end of the first link member 731 is connected to the movable member 71, and the other end of the first link member 731 is connected to one end of the second link member 732 by a first connecting shaft 734. The other end of the second link member 732 is connected to one end of the third link member 733 by a second connecting shaft 735. The other end of the third link member 733 is connected to one end of the cover member 102 by a third connecting shaft 737.

[0087] The third link member 733 is rotatably supported by the second support shaft 736.

[0088] The first directional movement mechanism 73 moves the movable member 71 toward the rear along the first direction D1 in conjunction with the movement of the cover member 102 in the first operating direction. The first directional movement mechanism 73 also moves the movable member 71 toward the front along the first direction D1 in conjunction with the movement of the cover member 102 in the second operating direction.

[0089] When the movable member 71 moves in conjunction with the movement of the cover member 102 in the first operating direction, the roller 71a rolls along the inclined surface 7a and pushes the inclined surface 7a toward the second side D22. As a result, the unit moving mechanism 7 moves the heating unit 5a from the retracted position to the close position against the biasing force of the first biasing member 72.

[0090] The restricting section 11 restricts the range of movement of the fixing unit 5b toward the second side D22. As the roller 71a moves the heating unit 5a toward the second side D22, the fixing unit 5b and the heating unit 5a are sandwiched between the movable member 71 and the restricting section 11 (see Figures 3 and 5).

[0091] Figure 5 shows the unit movement mechanism 7 in a biased state in which the movable member 71 biases the heating unit 5a and the fixing unit 5b toward the regulating section 11. Figures 3 and 5 show the fixing device 5 in a proximity state in which the heating unit 5a is held in the proximity position by the unit movement mechanism 7.

[0092] The fixing unit 5b and the heating unit 5a are positioned in the second direction D2 by being sandwiched between the movable member 71 and the regulating part 11.

[0093] The first support 54 has a plurality of concave first fitting portions 54a that open to the second side D22 (see Figures 3 and 4). The second support 55 has a plurality of convex second fitting portions 55a that can each be fitted into the plurality of first fitting portions 54a (see Figures 3 and 4).

[0094] The unit movement mechanism 7 moves the heating unit 5a to the second side D22, causing the multiple first fitting portions 54a and the multiple second fitting portions 55a to engage (see Figure 3).

[0095] The engagement of the multiple first fitting portions 54a and the multiple second fitting portions 55a restricts the relative movement of the heating unit 5a and the fixing unit 5b in the vertical direction D3.

[0096] The second support 55 may be provided with a first fitting portion 54a, and the first support 54 may be provided with a second fitting portion 55a.

[0097] On the other hand, when the movable member 71 moves in conjunction with the movement of the cover member 102 in the second operating direction, the roller 71a rolls on the inclined surface 7a, and the first biasing member 72 moves the heating unit 5a to the first side D21.

[0098] Figure 6 shows the unit movement mechanism 7 in a pulling state, where the first biasing member 72 is pulling the heating unit 5a toward the first side D21. Figures 4 and 6 show the fixing device 5 in a separated state, where the heating unit 5a is pulled away from the fixing unit 5b toward the first side D21 by the unit movement mechanism 7. The separated state is the state in which the heating unit 5a is in the retracted position.

[0099] The coupling mechanism 560 comprises a shaft portion 561, an engaging portion 562, and a second biasing member 563 (see Figures 7 and 8).

[0100] The shaft portion 561 is formed to protrude from the heating unit 5a toward the first side D21 in the second direction D2. In this embodiment, the first end of the shaft portion 561 is fixed to the duct forming member 541.

[0101] The shaft portion 561 is inserted through a through hole 56a formed in the unit connecting member 56 along the second direction D2. The engaging portion 562 is formed at the second end of the shaft portion 561. The engaging portion 562 is larger than the inner diameter of the through hole 56a.

[0102] The engaging portion 562 engages with the edge of the through hole 56a in the unit connecting member 56 when the unit connecting member 56 moves toward the first side D21 in the second direction D2, preventing the shaft portion 561 from coming out of the through hole 56a.

[0103] The second biasing member 563 is positioned between the unit connecting member 56 and the heating unit 5a. As a result, the second biasing member 563 functions as a spacer that forms a gap 5600 between the unit connecting member 56 and the heating unit 5a.

[0104] In this embodiment, the second biasing member 563 is positioned between the unit connecting member 56 and the duct forming member 541, forming a gap 5600 between the unit connecting member 56 and the duct forming member 541.

[0105] When the unit movement mechanism 7 is in the biased state, the engagement of the engaging portion 562 with the unit connecting member 56 is released, and the second biasing member 563 elastically biases the duct forming member 541 toward the second side D22 while forming a gap 5600 (see Figure 7). As a result, the heating unit 5a moves from the retracted position to the close position and is positioned in the close position.

[0106] On the other hand, when the unit movement mechanism 7 is in the pulled position, the engaging portion 562 engages with the unit connecting member 56, and a force acting from the shaft portion 561 on the duct forming member 541 pulls the duct forming member 541 toward the first side D21 in the second direction D2 (see Figure 8). As a result, the heating unit 5a moves from the close position to the retracted position.

[0107] Furthermore, the image forming apparatus 10 is further equipped with a first directional biasing mechanism 8 attached to the inner surface of the cover member 102 (see Figures 5 and 6). In addition, the second support 55 of the fixing unit 5b has a projection 55b that protrudes from the lower surface of the second support 55 (see Figures 3 and 4).

[0108] The first directional biasing mechanism 8 comprises a spring 80, a spring case 81, and a cap portion 82 (see Figure 7).

[0109] The spring case 81 houses the spring 80. The cap portion 82 is movably attached to the spring case 81. The spring 80 is an example of an elastic member.

[0110] The spring 80 is sandwiched between the cover member 102 and the second support 55 of the fixing unit 5b when the cover member 102 is in the closed position. In this embodiment, the spring 80 and the cap portion 82 are sandwiched between the cover member 102 and the second support 55.

[0111] The spring 80 is sandwiched between the cover member 102 and the second support 55, thereby elastically biasing the second support 55 in the mounting direction D12 (see Figure 7). The mounting direction D12 is the opposite direction to the pulling direction D11 of the fixing unit 5b.

[0112] Furthermore, when the cover member 102 is in the closed position, the force received by the second support member 55 from the spring 80 causes the projection 55b to come into contact with the lower support member 12.

[0113] The fixing unit 5b is positioned in the first direction D1 by the action of the spring 80 and the projection 55b. The first direction biasing mechanism 8 may be attached to the second support 55 of the fixing unit 5b.

[0114] The first link member 731 moves along the first direction D1 in conjunction with the movement of the cover member 102. The first link member 731 is positioned along the first direction D1 from the end in the first direction D1 on the side where the cover member 102 is located within the main body 1 to the position facing the unit connecting member 56 (see Figures 5 and 6).

[0115] One or more ventilation openings 731a are formed in the first link member 731 in the portion located between one of the pair of fans 6 and one of the pair of inlet openings 540b (see Figure 5). Air sent out from one of the pair of fans 6 flows smoothly through the ventilation opening 731a to one of the pair of inlet openings 540b.

[0116] Incidentally, in the image forming apparatus 10, there is a risk that scattered toner may enter between the heating unit 5a and the fixing unit 5b. The entry of scattered toner between the heating unit 5a and the fixing unit 5b may cause noise in the image on the sheet 900.

[0117] Therefore, the fixing device 5 is equipped with a sealing member 57 that fills the gap between the heating unit 5a and the fixing unit 5b (see Figures 3 and 4). However, there are cases where the gap between the heating unit 5a and the fixing unit 5b cannot be sufficiently narrowed. In this case, it is necessary to use a sealing member 57 with a larger thickness.

[0118] If the thickness of the sealing member 57 is large, the sealing member 57 may bend when the heating unit 5a is brought close to the fixing unit 5b, which may result in a sealing failure.

[0119] In the fixing device 5, the sealing member 57 has a structure that makes it difficult for sealing defects to occur due to bending. The structure will be described below.

[0120] The fixing unit 5b has an opposing surface 55c that faces a portion of the heating unit 5a. The heating unit 5a has an adhesive surface 54c that faces the opposing surface 55c (see Figures 3, 4, and 9). The adhesive surface 54c is the surface to which the sealing member 57 is adhered.

[0121] In this embodiment, the adhesive surface 54c is formed on the first support 54 of the heating unit 5a, and the opposing surface 55c is formed on the second support 55 of the fixing unit 5b.

[0122] The opposing surface 55c and the adhesive surface 54c are each formed along the first direction D1 (see Figure 9). That is, the longitudinal direction of the opposing surface 55c and the adhesive surface 54c is the first direction D1.

[0123] The sealing member 57 is positioned with the first direction D1 as its longitudinal direction and is bonded to the adhesive surface 54c (see Figures 9 and 10). The sealing member 57 is an elastic member that is sandwiched between the opposing surface 55c and the adhesive surface 54c when the heating unit 5a is in the aforementioned proximity position (see Figure 3).

[0124] The sealing member 57 elastically contracts when sandwiched between the opposing surface 55c and the adhesive surface 54c.

[0125] The sealing member 57 has a structure in which a first foam member 571, a resin sheet 572, and a second foam member 573 are laminated (see Figures 9 and 10). The first foam member 571 is bonded to the adhesive surface 54c of the heating unit 5a. The resin sheet 572 is bonded to the first foam member 571. The second foam member 573 is bonded to the resin sheet 572.

[0126] In this embodiment, the adhesive surface 54c, the first foam member 571, the resin sheet 572, and the second foam member 573 are bonded to each other by a plurality of double-sided tapes. Alternatively, the adhesive surface 54c, the first foam member 571, the resin sheet 572, and the second foam member 573 may be bonded together with an adhesive.

[0127] For example, the first foam member 571 and the second foam member 573 are each made of ethylene propylene rubber foam or urethane rubber foam, etc. The resin sheet 572 is made of polycarbonate sheet material, etc. Alternatively, an acrylic sheet may be used as the resin sheet 572.

[0128] In the example shown in Figure 10, a notch 57x is formed at one end of the first foam member 571, the resin sheet 572, and the second foam member 573 in the first direction D1 (see Figure 10). The notch 57x is formed to avoid interference between the sheet metal member 1b, which forms part of the main frame 1x, and the sealing member 57.

[0129] In this embodiment, a relatively thick sealing member 57 is constructed from a first foam member 571 and a second foam member 573, which are relatively thin. The resin sheet 572 contributes to preventing the sealing member 57 from bending without hindering its stretchability in the thickness direction.

[0130] By employing the sealing member 57, even when the gap between the opposing surface 55c and the adhesive surface 54c cannot be sufficiently narrowed, sealing defects caused by bending of the sealing member 57 are less likely to occur.

[0131] In the example shown in Figures 3 and 4, the adhesive surface 54c is the second side D22 in the second direction D2 at the lower edge of the first support 54, and the opposing surface 55c is the first side D21 in the second direction D2 at the lower edge of the second support 55.

[0132] Between the heating unit 5a and the fixing unit 5b, an upward airflow is generated when the air is heated by the heater 51. Therefore, the scattered toner is less likely to enter the gap between the upper edge of the heating unit 5a and the upper edge of the fixing unit 5b, but is more likely to enter the gap between the lower edge of the heating unit 5a and the lower edge of the fixing unit 5b.

[0133] In this embodiment, the sealing member 57 is positioned in the gap between the lower edge of the heating unit 5a and the lower edge of the fixing unit 5b, where the scattered toner is likely to enter.

[0134] Furthermore, since the fan 6 blows air toward the heating unit 5a, the scattered toner is easily carried by the airflow from the fan 6 into the gap between the heating unit 5a and the fuser unit 5b. The sealing member 57 is particularly effective in the fuser device 5, which is cooled by the fan 6.

[0135] [First variation] Next, a modified example of the sealing member 57, the sealing member 57A, will be described with reference to Figure 11.

[0136] The sealing member 57A, like the sealing member 57, has a structure in which a first foam member 571, a resin sheet 572, and a second foam member 573 are laminated together.

[0137] In the sealing member 57A, the first foam member 571 consists of a plurality of unit foam members 571a arranged at intervals in the first direction D1. Each of the plurality of unit foam members 571a is arranged with the first direction D1 as its longitudinal direction and is bonded to the adhesive surface 54c.

[0138] The heating unit 5a, which has a sealing member 57A, has one or more protrusions 58 that protrude from the adhesive surface 54c. The protrusions 58 are arranged between a plurality of unit foam members 571a on the adhesive surface 54c.

[0139] In other words, the first foamed member 571 of the sealing member 57A is divided into a plurality of unit foamed members 571a to avoid interference with the protruding portion 58.

[0140] In the example shown in Figure 11, the first foam member 571 consists of four unit foam members 571a, and the heating unit 5a has three protrusions 58. Each of the protrusions 58 is the head of a screw that is screwed into the adhesive surface 54c of the first support 54.

[0141] In the sealing member 57A, the resin sheet 572 serves to connect and reinforce multiple unit foam members 571a. When the sealing member 57A is used, the same effects as when the sealing member 57 is used can be obtained.

[0142] [Second variation] Next, a modified example of the fixing device 5, namely fixing device 5A, will be described with reference to Figure 12.

[0143] In the fixing device 5A, the heating unit 5a has a pair of adhesive surfaces 54c at two locations on the lower and upper edges of the first support 54, and the fixing unit 5b has a pair of opposing surfaces 55c at two locations on the lower and upper edges of the second support 55.

[0144] Furthermore, the fixing device 5A has a pair of sealing members 57 bonded to a pair of adhesive surfaces 54c. When the fixing device 5A is used, the same effects as when the fixing device 5 is used can be obtained.

[0145] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0146] <Note 1> A transfer device that transfers a toner image formed on an image carrier to a sheet, A fixing device that fixes the toner image on the sheet by heating and pressurizing the toner image on the sheet, The device includes a unit moving mechanism for moving a part of the fixing device, The fixing device is A fixing unit having a heating fixing member and a pressurizing member that biases the sheet on which the toner image is formed toward the fixing member, and arranged with the first direction as the longitudinal direction, The heating unit comprises a heater for heating the fixing member, and is positioned adjacent to the fixing unit in a second direction intersecting the first direction, with the first direction being the longitudinal direction. The unit movement mechanism is a mechanism that moves the heating unit between a position close to the fixing unit and a retracted position further away from the fixing unit than the close position. The fixing unit has a facing surface that is opposite to a part of the heating unit and is formed along the first direction, The aforementioned heating unit is An adhesive surface formed facing the opposing surface and along the first direction, The device comprises an elastic sealing member which is arranged with the first direction as the longitudinal direction, is bonded to the adhesive surface, and is sandwiched between the opposing surface and the adhesive surface when the heating unit is in the proximity position, The sealing member has a structure in which a first foam member bonded to the adhesive surface, a resin sheet bonded to the first foam member, and a second foam member bonded to the resin sheet are laminated together, in an image forming apparatus.

[0147] <Note 2> The first foam member consists of a plurality of unit foam members, each arranged with the first direction as its longitudinal direction and spaced apart in the first direction. The image forming apparatus according to Appendix 1, wherein the heating unit has one or more protrusions positioned to protrude between the plurality of unit foam members on the bonding surface.

[0148] <Note 3> The image forming apparatus according to Appendix 1 or Appendix 2, wherein the resin sheet is a polycarbonate sheet member.

[0149] <Note 4> The image forming apparatus according to any one of the appendices 1 to 3, wherein the heating unit comprises a ventilation duct having an inlet opening positioned opposite the fan, a cavity communicating with the inlet opening, and an outlet opening communicating with the cavity. [Explanation of symbols]

[0150] 4: Printing device 5,5A: Fixing device 5a: Heating unit 5b: Fixing unit 6: Fan 7: Unit movement mechanism 10: Image forming apparatus 41: Photoreceptor (image carrier) 43: Developing equipment 45: Transfer device 51: Heater 52: Fixing belt (fixing member) 53: Pressure roller (pressure component) 54: 1st support 54c: Adhesive surface 55:Second support 55c: Opposing surface 57, 57A: Sealing material 58: Protrusion 70: Guide member 71: Movable member 72: First biasing member 73: First direction movement mechanism 454: Support roller 520: Fixing roller 540: Ventilation duct 563: Second biasing member 571: First foamed member 571a: Unit foamed material 572: Resin sheet 573: Second foamed material

Claims

1. A transfer device that transfers a toner image formed on an image carrier to a sheet, A fixing device that fixes the toner image on the sheet by heating and pressurizing the toner image on the sheet, The device includes a unit moving mechanism for moving a part of the fixing device, The fixing device is A fixing unit having a heating fixing member and a pressurizing member that biases the sheet on which the toner image is formed toward the fixing member, with the first direction being the longitudinal direction, The heating unit comprises a heater for heating the fixing member, and is positioned adjacent to the fixing unit in a second direction intersecting the first direction, with the first direction being the longitudinal direction. The unit movement mechanism is a mechanism that moves the heating unit between a position close to the fixing unit and a retracted position further away from the fixing unit than the close position. The fixing unit has a facing surface that is opposite to a part of the heating unit and is formed along the first direction, The aforementioned heating unit is An adhesive surface formed facing the opposing surface and along the first direction, The device comprises an elastic sealing member which is arranged with the first direction as the longitudinal direction, is bonded to the adhesive surface, and is sandwiched between the opposing surface and the adhesive surface when the heating unit is in the proximity position, The sealing member has a structure in which a first foam member bonded to the adhesive surface, a resin sheet bonded to the first foam member, and a second foam member bonded to the resin sheet are laminated together, in an image forming apparatus.

2. The first foam member consists of a plurality of unit foam members, each arranged with its longitudinal direction as the first direction and spaced apart in the first direction. The image forming apparatus according to claim 1, wherein the heating unit has one or more protrusions positioned to protrude between the plurality of unit foam members on the bonding surface.

3. The image forming apparatus according to claim 1 or claim 2, wherein the resin sheet is a polycarbonate sheet member.

4. The image forming apparatus according to claim 1 or 2, wherein the heating unit comprises a ventilation duct having an inlet opening positioned opposite the fan, a cavity communicating with the inlet opening, and an outlet opening communicating with the cavity.

Images