Image forming device

Abstract

To guide a sheet guide part provided on a cover to an appropriate position even when a plurality of column parts in a main body frame are arranged at a relatively small interval.SOLUTION: A guide unit holding part 553 is formed at a position between two column parts 11 in a longitudinal direction of a fixing unit 5b. When a main cover part 6 rotates from an open position to a closed position, a part to be supported 71 of an oscillation guide unit 7 moves from a position separated from the guide unit holding part 553 to a position in contact with the guide unit holding part 553. The part to be supported 71 slides on the guide unit holding part 553. By the part to be supported 71 sliding on the guide unit holding part 553, the oscillation guide unit 7 oscillates upward, and subsequently the oscillation guide unit 7 is held at a target position by the guide unit holding part 553.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus provided with a cover having a guide portion for guiding a sheet. [Background technology]

[0002] In an image forming apparatus, a pair of sheet guide sections arranged opposite to each other form a sheet transport path.

[0003] In addition, one of the pair of sheet guide portions may be provided on a cover that can open and close a part of the main body (see, for example, Patent Document 1).

[0004] When the cover is opened, the pair of sheet guide portions are separated from each other, which makes it possible to easily clear a jam in the sheet transport path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-156476 Summary of the Invention [Problem to be solved by the invention]

[0006] When the cover is closed, it is necessary that one of the pair of sheet guide portions provided on the cover be properly positioned within the main body.

[0007] For example, a guide mechanism for guiding a member provided on the cover to an appropriate position may be provided on a plurality of support columns of the main body frame.

[0008] On the other hand, in order to reduce the size of the image forming apparatus, the support columns of the main body frame may be arranged at relatively small intervals, making it difficult to secure space for providing the guide mechanism on the support columns.

[0009] The object of the present invention is to provide an image forming device that can guide a sheet guide section provided on a cover to an appropriate position even when multiple support sections on the main frame are arranged at relatively small intervals. [Means for solving the problem]

[0010] According to one aspect of the present invention, an image forming apparatus includes a main frame, a fixing unit, and a main cover. The fixing unit includes a fixing member heated by a heater and a pressure member that presses a sheet against the fixing member, and is attached to the main frame. The main cover is rotatably supported. The main frame includes two support columns. The two support columns are arranged along a protective side surface that forms one end of the fixing unit in the short direction, extending vertically and spaced apart in the longitudinal direction of the fixing unit. The main cover is rotatably supported between a closed position that covers the protective side surface of the fixing unit and an open position that exposes the protective side surface of the fixing unit. The image forming apparatus further includes a swing guide unit. The swing guide unit includes a post-fixing guide member that guides the sheet that has passed between the fixing member and the pressure member, and is supported by the main cover to be swingable up and down. The fixing unit includes a guide unit holder. The guide unit holding portion is formed at a position between the two support pillars in the longitudinal direction of the fixing unit. The oscillating guide unit has a supported portion that can come into contact with the guide unit holding portion. When the main cover portion rotates from the open position to the closed position, the supported portion moves from a position away from the guide unit holding portion to a position in contact with the guide unit holding portion, and the supported portion then slides on the guide unit holding portion. As the supported portion slides on the guide unit holding portion, the oscillating guide unit oscillates upward due to the force it receives from the guide unit holding portion, and then the oscillating guide unit is held at the target position by the guide unit holding portion. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an image forming device that can guide a sheet guide section provided on a cover to an appropriate position even when multiple support sections on the main frame are arranged at relatively small intervals. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a configuration diagram of the fixing device in the image forming apparatus according to the embodiment. [Figure 3] FIG. 3 is a perspective view of a main body frame of the image forming apparatus according to the embodiment. [Figure 4] FIG. 4 is a side view of the fixing unit and the swing guide unit and their surroundings in the image forming apparatus according to the embodiment (with the main cover open). [Figure 5] FIG. 5 is a plan view of the fixing unit and the swing guide unit and their surroundings in the image forming apparatus according to the embodiment (with the main cover open). [Figure 6] FIG. 6 is a side view of the fixing unit and the swing guide unit and their surroundings in the image forming apparatus according to the embodiment (in a state where the main cover is being closed). [Figure 7] FIG. 7 is a side view of the fixing unit and the swing guide unit and their surroundings in the image forming apparatus according to the embodiment (with the main cover closed). [Figure 8] FIG. 8 is a plan view of the fixing unit and the swing guide unit and their surroundings in the image forming apparatus according to the embodiment (with the main cover closed). DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention.

[0014] [Configuration of image forming apparatus 10] The image forming apparatus 10 according to the embodiment includes a printing device 4 that performs a printing process to form an image on a sheet 9 .

[0015] The printing device 4 performs the printing process by electrophotography. The sheet 9 is an image forming medium such as paper or a sheet-like resin member.

[0016] As shown in FIG. 1, an image forming apparatus 10 includes a main body 1, a sheet conveying device 3, and a printing device 4 provided therein.

[0017] The main body 1 includes a main body frame 1x and an exterior member 100 (see FIGS. 3, 5, and 8). The exterior member 100 is attached to the main body frame 1x and covers the main body frame 1x.

[0018] The main body frame 1x is made up of a combination of multiple metal pipes (see FIG. 3). The exterior member 100 is attached to the main body frame 1x. The exterior member 100 forms the exterior of the image forming apparatus 10.

[0019] The printing device 4 includes one or more image forming units 4x, an optical scanning device 40, a transfer device 44, and a fixing device 5. The image forming unit 4x includes a drum-shaped photosensitive member 41, a charging device 42, a developing device 43, a drum cleaning device 45, and the like.

[0020] The sheet transport device 3 includes a feed-out device 31, multiple pairs of main transport rollers 32, and multiple pairs of sub-transport rollers 33. The sheet transport device 3 further includes a drive device (not shown). The drive device drives the feed-out device 31, multiple pairs of main transport rollers 32, and multiple pairs of sub-transport rollers 33.

[0021] The delivery device 31 delivers the sheets 9 stored in the sheet storage unit 2 to a main transport path 301 in the main body 1. The main transport path 301 and an auxiliary transport path 302 (described later) are paths for the sheets 9.

[0022] The main transport path 301 is a path that extends from an entrance facing the delivery device 31 to a discharge port 301a via a registration position P1, a transfer position P2, and a fixing position P3.

[0023] The plurality of main transport roller pairs 32 transport the sheet 9 along the main transport path 301. The plurality of main transport roller pairs 32 include a registration roller pair 32a, a pull-in roller pair 32b, and a discharge roller pair 32c.

[0024] In this embodiment, the transfer position P2 is located above the registration position P1, and the fixing position P3 is located above the transfer position P2. Also, the discharge port 301a is located above the fixing position P3.

[0025] The printing device 4 forms a toner image on the sheet 9 transported along the main transport path 301. The toner image is an image using toner as a developer. The toner is an example of the granular developer.

[0026] 1 is a tandem color image forming apparatus, and therefore the printing device 4 includes a plurality of image forming units 4x corresponding to the toners of a plurality of colors.

[0027] In this embodiment, the printing device 4 includes four image forming units 4x corresponding to four colors: yellow, cyan, magenta, and black.

[0028] In each image forming unit 4x, a photoconductor 41 rotates, and a charging device 42 charges the surface of the photoconductor 41. Furthermore, an optical scanning device 40 writes an electrostatic latent image on the surface of the photoconductor 41 by scanning with a light beam.

[0029] Furthermore, the developing device 43 develops the electrostatic latent image into the toner image by supplying the toner to the surface of the photoreceptor 41. The photoreceptor 41 is an example of an image carrier that rotates while carrying the toner image.

[0030] The transfer device 44 transfers the toner image onto the sheet 9 at a transfer position P2 on the main transport path 301. The transfer device 44 includes an intermediate transfer belt 441, four primary transfer devices 442 corresponding to the four image forming units 4x, a secondary transfer device 443, and a belt cleaning device 444.

[0031] Each primary transfer device 442 transfers the toner image on the surface of each photoconductor 41 onto the surface of the intermediate transfer belt 441. As a result, a color toner image is formed on the surface of the intermediate transfer belt 441.

[0032] The secondary transfer device 443 transfers the toner image formed on the intermediate transfer belt 441 onto the sheet 9 at a transfer position P2 on the main transport path 301.

[0033] When the image forming apparatus 10 is a monochrome image forming apparatus, the secondary transfer device 443 transfers the toner image on the photosensitive member 41 onto the sheet 9 at the transfer position P2.

[0034] The drum cleaning device 45 removes the waste toner remaining on the surface of the photosensitive member 41. The belt cleaning device 444 removes the waste toner remaining on the intermediate transfer belt 441.

[0035] The fixing device 5 applies heat and pressure to the toner image on the sheet 9 at a fixing position P3 on the main transport path 301. In this way, the fixing device 5 fixes the toner image onto the sheet 9.

[0036] As shown in FIG. 2, the fixing device 5 includes a heater 51, a fixing belt 52, a fixing roller 520, another heater 51, a pressure roller 53, and a sheet separating member 5200.

[0037] The fixing belt 52 is a flexible cylindrical member that encloses a fixing roller 520. The fixing belt 52 is heated by a heater 51.

[0038] Fixing roller 520 is a cylindrical member that supports fixing belt 52 on its inside. Fixing roller 520 has cylindrical core metal portion 521 and elastic portion 522 formed on the outer periphery of core metal portion 521.

[0039] The fixing roller 520 is rotatably supported, and the fixing belt 52 is rotatable together with the fixing roller 520.

[0040] The fixing belt 52 has a conductive substrate, an elastic layer formed on the outer periphery of the substrate, and a release layer formed on the outer periphery of the elastic layer.

[0041] The heater 51 is disposed opposite the outer peripheral surface of 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.

[0042] Pressure roller 53 is rotatably supported. Similar to fixing roller 520, pressure roller 53 also has a cylindrical core metal portion 531 and an elastic portion 532 formed on the outer periphery of core metal portion 531.

[0043] The pressure roller 53 is driven to rotate by a drive unit (not shown). The fixing belt 52 and the fixing roller 520 rotate in conjunction with the pressure roller 53.

[0044] The fixing belt 52 heats the toner image formed on the sheet 9. The pressure roller 53 presses the toner image toward the sheet 9.

[0045] 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 presses the sheet 9 against the fixing belt 52.

[0046] When the sheet 9 adheres to the fixing belt 52, the sheet separating member 5200 separates the sheet 9 from the fixing belt 52.

[0047] The auxiliary transport path 302 branches off from the main transport path 301 at a portion between the fixing position P3 and the discharge port 301a. The auxiliary transport path 302 also merges with the main transport path 301 at a portion upstream of the registration position P1.

[0048] The pair of registration rollers 32a is disposed at a registration position P1. The pair of registration rollers 32a temporarily stops the sheet 9 at the registration position P1 and then sends it out to a transfer position P2.

[0049] The pair of pull-in rollers 32b pulls the sheet 9 that has passed through the fixing position P3 out of the fixing device 5, and further transports the sheet 9 toward the discharge opening 301a.

[0050] The sheet 9 that has passed between the fixing belt 52 and the pressure roller 53 is conveyed to the discharge roller pair 32c by the pull-in roller pair 32b.

[0051] The discharge roller pair 32c is disposed at the discharge opening 301a. The discharge roller pair 32c rotates in a first rotation direction to discharge the sheet 9 that has passed through the pull-in roller pair 32b from the discharge opening 301a onto the discharge tray 1a.

[0052] On the other hand, the discharge roller pair 32c rotates in the second rotation direction to invert and transport the sheet 9. The discharge roller pair 32c transports the inverted sheet 9 from the main transport path 301 to the sub transport path 302.

[0053] The sheet conveying device 3 further includes a first sheet guide member 35, a second sheet guide member 36, and a third sheet guide member 37 (see FIG. 1).

[0054] The first sheet guide member 35 and the second sheet guide member 36 are disposed opposite each other and form a part of the main transport path 301. The second sheet guide member 36 and the third sheet guide member 37 are disposed opposite each other and form a part of the sub-transport path 302.

[0055] The surface of the second sheet guide member 36 facing the first sheet guide member 35 is a first guide surface 36a (see FIGS. 1 and 4). The surface of the second sheet guide member 36 facing the third sheet guide member 37 is a second guide surface 36b (see FIGS. 1 and 4).

[0056] In the following description, the portion of the main transport path 301 extending from between the fixing belt 52 and the pressure roller 53 to the pair of discharge rollers 32c will be referred to as a subsequent transport path 3010. The subsequent transport path 3010 is an example of a first transport path. The sub-transport path 302 is an example of a second transport path branching off from the first transport path.

[0057] The first sheet guide member 35 and the first guide surface 36a form a part of the rear-stage conveying path 3010. The first guide surface 36a forms a partition wall of a part of the rear-stage conveying path 3010. The first guide surface 36a guides the sheet 9 that has passed through the pull-in roller pair 32b toward the discharge roller pair 32c.

[0058] The second sheet guide member 36 is an example of a post-fixing guide member that guides the sheet 9 that has passed between the fixing belt 52 and the pressure roller 53.

[0059] The discharge roller pair 32c can discharge the sheet 9 guided by the first guide surface 36a of the second sheet guide member 36 onto the discharge tray 1a.

[0060] The second guide surface 36b and the third sheet guide member 37 form a base end portion of the auxiliary transport path 302. The second guide surface 36b forms a partition wall of part of the auxiliary transport path 302. The second guide surface 36b guides the sheet 9 that has been turned over by the discharge roller pair 32c that rotates in the second rotation direction from the subsequent transport path 3010 to the auxiliary transport path 302.

[0061] For example, the discharge roller pair 32c, the first sheet guide member 35, and the third sheet guide member 37 are unitized as the discharge unit 34. That is, the discharge unit 34 includes the discharge roller pair 32c, the first sheet guide member 35, and the third sheet guide member 37.

[0062] The plurality of pairs of sub-transport rollers 33 transport the sheet 9 along the sub-transport path 302. One of the plurality of pairs of sub-transport rollers 33 sends the sheet 9 from the sub-transport path 302 to a registration position P1 on the main transport path 301.

[0063] When the sheet transport device 3 transports the sheet 9 twice along the main transport path 301 using the sub-transport path 302, the printing device 4 executes double-sided printing processing. The double-sided printing processing is processing for forming images on both sides of the sheet 9.

[0064] In this embodiment, the fixing device 5 is divided into a heating unit 5a and a fixing unit 5b (see FIGS. 4 and 5).

[0065] 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.

[0066] First support 54 is a member that supports heater 51. Second support 55 is a member that supports fixing belt 52, fixing roller 520, and pressure roller 53. Fixing belt 52 is supported by second support 55 via fixing roller 520.

[0067] The heating unit 5a, the fixing unit 5b, and the discharge unit 34 are attached to the main body frame 1x. The fixing unit 5b is disposed next to the heating unit 5a (see FIG. 4).

[0068] The plurality of metal pipes that make up the main body frame 1x have two support columns 11 and two beams 12 (see FIG. 3).

[0069] The two support columns 11 extend in a vertical direction D3 and are spaced apart in a first direction D1 (see FIG. 3). The vertical direction D3 is the up-down direction. The first direction D1 is the longitudinal direction of the fixing unit 5b attached to the main body frame 1x.

[0070] The two support pillars 11 are formed to the sides of the fixing unit 5b and extend in the vertical direction D3 (see FIGS. 4 and 9).

[0071] The first direction D1 is also a direction along the center line of rotation of the fixing belt 52 and the pressure roller 53. In this embodiment, the first direction D1 is the depth direction of the image forming apparatus 10.

[0072] The two support columns 11 include a first support column 11a disposed on the front side of the image forming apparatus 10 and a second support column 11b disposed on the rear side of the image forming apparatus 10 (see FIGS. 3 and 5).

[0073] The two beams 12 are formed below the heating unit 5a and the fixing unit 5b, extending in the horizontal direction, and are spaced apart in the first direction D1 (see FIGS. 3 and 5). The horizontal direction is the width direction of the image forming apparatus 10.

[0074] The two beams 12 are respectively connected to the two support columns 11 (see FIG. 3). For example, the two beams 12 are respectively connected to the two support columns 11 by welding.

[0075] The two beam portions 12 include a first beam portion 12a disposed on the front side of the image forming apparatus 10 and a second beam portion 12b disposed on the rear side of the image forming apparatus 10 (see FIGS. 3 and 5).

[0076] The fixing unit 5b is disposed between the heating unit 5a and the two support columns 11 (see FIG. 4).

[0077] The heating unit 5a is placed on two beams 12 in a state in which it is bridged across the two beams 12. Similarly, the fixing unit 5b is placed on two beams 12 in a state in which it is bridged across the two beams 12.

[0078] The heating unit 5a and the fixing unit 5b are placed on two beams 12 with their longitudinal directions aligned with the first direction D1 (see FIGS. 5 and 8).

[0079] The exterior member 100 has a first opening 101, a second opening 102, a main cover portion 6, and an auxiliary cover portion 103 (see FIGS. 1, 5, and 8).

[0080] The first opening 101 is a portion where an opening is formed that exposes the protection side surface 55a of the fixing unit 5b (see FIGS. 5 and 8). The protection side surface 55a is a side surface that forms one end of the fixing unit 5b in the second direction D2.

[0081] The second direction D2 is the widthwise direction of the fixing unit 5b. The heating unit 5a and the fixing unit 5b are arranged side by side in the second direction D2. The two support pillars 11 are arranged along the protective side surface 55a (see FIG. 4).

[0082] The second opening 102 is a portion where an opening that opens one end of the fixing unit 5b in the first direction D1 is formed (see FIGS. 5 and 8).

[0083] The main cover part 6 can open and close the first opening 101. For example, the main cover part 6 is supported by the main body frame 1x. Alternatively, the main cover part 6 may be supported by the edge of the first opening 101 in the exterior member 100.

[0084] The main cover part 6 is supported rotatably around a lower support shaft 6x (see FIG. 1) and is rotatable between a closed position where it covers the protective side surface 55a of the fixing unit 5b and an open position where it exposes the protective side surface 55a.

[0085] One of a pair of partition walls that form the auxiliary transport path 302 is formed on the inner surface of the main cover part 6. Furthermore, some of the multiple pairs of auxiliary transport rollers 33 are arranged on the inner surface of the main cover part 6.

[0086] When the main cover part 6 is opened, one of the pair of partition walls that form the sub-transport path 302 is separated from the other, which makes it possible to easily clear a jam in the sub-transport path 302.

[0087] The second sheet guide member 36 is also disposed on the inner surface of the main cover portion 6 (see FIGS. 1 and 4). When the main cover portion 6 is opened, the second sheet guide member 36 is separated from the first sheet guide member 35 and the third sheet guide member 37. This makes it possible to easily clear a jam in the subsequent conveying path 3010.

[0088] The auxiliary cover part 103 is supported so as to be able to open and close the second opening 102 (see FIG. 5). The auxiliary cover part 103 is supported on the edge of the second opening 102 in the exterior member 100. The auxiliary cover part 103 is supported so as to be able to rotate by a support shaft 103x.

[0089] By moving the heating unit 5a to a position away from the fixing unit 5b, the fixing unit 5b can be pulled out from the main body frame 1x along the first direction D1 (see FIG. 5).

[0090] The fixing unit 5b can be pulled out from the main body frame 1x with the auxiliary cover 103 open. The fixing unit 5b is pulled out from the main body frame 1x to the outside of the main body 1 through the second opening 102.

[0091] Incidentally, it is necessary that the second sheet guide member 36 provided on the main cover portion 6 be properly positioned within the main body 1 when the cover is closed.

[0092] For example, a guide mechanism for guiding the second sheet guide member 36 provided on the main cover portion 6 to an appropriate position may be provided on the two support pillars 11 of the main body frame 1x.

[0093] On the other hand, in order to reduce the size of the image forming apparatus 10, the two support pillars 11 in the main body frame 1x may be arranged with a relatively small gap between them. In this case, it is difficult to secure a space for providing the guide mechanism on the two support pillars 11.

[0094] The image forming apparatus 10 has a configuration for guiding the second sheet guide member 36 provided on the main cover 6 to an appropriate position even when the two support pillars 11 are arranged with a relatively small gap between them. The configuration will be described below.

[0095] The image forming apparatus 10 includes a swing guide unit 7 attached to the main cover portion 6 (see FIGS. 1, 4 to 8). The swing guide unit 7 includes a second sheet guide member 36 and a unit support member 70.

[0096] The unit support member 70 supports the second sheet guide member 36. The unit support member 70 is supported by the main cover portion 6. The unit support member 70 is supported so as to be rotatable up and down about a lower support shaft 7x (see FIGS. 4 and 6).

[0097] The fixing unit 5b has two pillar contact portions 552 and one or more guide unit holding portions 553 (see FIGS. 4 to 8). The two pillar contact portions 552 are formed on the side surfaces of the two support pillars 11 so as to face each other.

[0098] The two pillar contact portions 552 respectively come into contact with the side surfaces of the two support pillars 11. The fixing unit 5b is sandwiched between the heater unit 5a and the two support pillars 11, and is thereby positioned in the second direction D2.

[0099] The guide unit holding portion 553 is formed at a position between the two support pillars 11 in the first direction D1.

[0100] The guide unit holding portion 553 is a portion that extends from an upper corner of the fixing unit 5b on the protective side surface 55a side to the upper surface of the fixing unit 5b. The guide unit holding portion 553 is a part of the second support body 55 of the fixing unit 5b.

[0101] In this embodiment, two guide unit holding portions 553 are formed at two locations spaced apart in the first direction D1 (see FIGS. 5 and 8).

[0102] The guide unit holding portion 553 comes into contact with the swing guide unit 7 when the main cover portion 6 rotates from the open position to the closed position (see FIG. 6). As a result, the guide unit holding portion 553 holds the swing guide unit 7 at the target position. For convenience, in FIG. 6, the support portion 11 and the beam portion 12 are shown by virtual lines (two-dot chain lines).

[0103] FIG. 7 shows a state in which the main cover portion 6 is closed and the swing guide unit 7 is held at the target position by the guide unit holding portion 553.

[0104] The swing guide unit 7 has a supported portion 71 that can come into contact with the guide unit holding portion 553. The supported portion 71 is a part of the unit support member 70.

[0105] In this embodiment, the swing guide unit 7 has two supported portions 71 corresponding to the two guide unit holding portions 553 (see FIGS. 5 and 8).

[0106] The movement of the swing guide unit 7 when the main cover portion 6 rotates from the open position to the closed position will now be described.

[0107] When the main cover part 6 rotates to the closed position, the supported part 71 moves from a position away from the guide unit holding part 553 to a position in contact with the guide unit holding part 553 (see FIGS. 4 and 6). Furthermore, the supported part 71 slides on the guide unit holding part 553.

[0108] As the supported portion 71 slides on the guide unit holding portion 553, the swing guide unit 7 swings upward due to the force it receives from the guide unit holding portion 553. After swinging upward, the swing guide unit 7 is held at the target position by the guide unit holding portion 553 (see FIG. 7).

[0109] In this embodiment, the discharge unit 34 has a first recessed fitting portion 340 that opens laterally (see FIGS. 4 to 8), while the unit support 70 has a second protruding fitting portion 72 (see FIGS. 4 to 8).

[0110] The first fitting portion 340 and the second fitting portion 72 are formed at a position between the two support columns 11 in the first direction D1 (see FIGS. 5 and 8).

[0111] In this embodiment, the first fitting portions 340 are formed at two locations spaced apart in the first direction D1 (see FIGS. 5 and 8). The swing guide unit 7 has two second fitting portions 72 corresponding to the two first fitting portions 340.

[0112] The first fitting portion 340 has a recess 341 that opens in the lateral direction, and a tapered surface 342 that continues to the edge of the recess 341 (see FIG. 4).

[0113] When the main cover part 6 rotates from the open position to the closed position, the second fitting part 72 fits into the recess 341 of the first fitting part 340 (see FIGS. 7 and 8). The tapered surface 342 guides the first fitting part 340 into the recess 341.

[0114] The second fitting portion 72 fits into the first fitting portion 340, thereby restricting movement of the swing guide unit 7 in the vertical direction D3 and the closing direction. The closing direction is the direction from the main cover portion 6 toward the discharge unit 34. As a result, the swing guide unit 7 is held at the target position also in the second direction D2.

[0115] In this embodiment, the image forming apparatus 10 includes a spring 60 supported by the swing guide unit 7 or the main cover part 6 (see FIGS. 4 and 7). The spring 60 biases the swing guide unit 7 toward the discharge unit 34 when the main cover part 6 is in the closed position (see FIG. 7).

[0116] The spring 60 biases the swing guide unit 7 toward the discharge unit 34, thereby maintaining the fitted state of the first fitting portion 340 and the second fitting portion 72.

[0117] The swing guide unit 7 may include the first fitting portion 340, and the discharge unit 34 may include the second fitting portion 72.

[0118] By adopting the image forming device 10, it is possible to realize a mechanism for guiding the second sheet guide member 36 to the appropriate target position even when the two support pillars 11 are arranged at a relatively small distance from each other. [Explanation of symbols]

[0119] 1: Main unit 1a: Output tray 1x: Main frame 3: Sheet transport device 4: Printing device 4x: Image forming section 5: Fixing device 5a: Heating unit 5b: Fixing unit 6: Main cover part 7: Swing guide unit 10: Image forming device 11: Support section 12:Beam part 32b: Pull-in roller pair 32c: Discharge roller pair 33: Sub-transport roller pair 34: Discharge unit 35: First sheet guide member 36: Second sheet guide member 36a: First guide surface 36b: Second guide surface 37: Third sheet guide member 40: Optical scanning device 41: Photoreceptor 42: Charging device 43: Developing device 44: Transcription device 51: Heater 52: Fixing belt 53: Pressure roller 54: 1st support 55:Second support 55a: Protective side 71: Supported part 72: Second fitting part 100: Exterior material 101: First opening 102: Second opening 103: Auxiliary cover part 301: Main transport route 302: Sub-transport route 340: First fitting part 341: Recess 342: Tapered surface 520: Fuser roller 553: Guide unit holder 3010: Rear transport path

Claims

1. The body frame and a fixing unit attached to the main body frame, the fixing unit having a fixing member heated by a heater and a pressure member for urging a sheet against the fixing member; an image forming apparatus including a main cover portion supported in a pivotable manner, the main body frame is disposed along a protective side surface that is a side surface that forms one end of the fixing unit in a short direction, and is formed to extend in a vertical direction, and has two support pillars that are disposed at an interval in the longitudinal direction of the fixing unit; the main cover portion is supported rotatably between a closed position that covers the protective side surface of the fixing unit and an open position that exposes the protective side surface of the fixing unit, the image forming apparatus, a swing guide unit having a post-fixing guide member that guides the sheet that has passed between the fixing member and the pressure member, the swing guide unit being supported by the main cover portion so as to be swingable up and down; a discharge unit attached to the main body frame, the discharge unit having a pair of discharge rollers capable of discharging the sheet that has passed between the fixing member and the pressure member onto a discharge tray, the fixing unit has a guide unit holding portion formed at a position between the two support pillars in the longitudinal direction of the fixing unit, the swing guide unit has a supported portion that can come into contact with the guide unit holding portion, When the main cover portion rotates from the open position to the closed position, the supported portion moves from a position separated from the guide unit holding portion to a position in contact with the guide unit holding portion, and further the supported portion slides on the guide unit holding portion, the supported portion slides on the guide unit holding portion, and the swing guide unit swings upward due to the force received from the guide unit holding portion, and then the swing guide unit is held at a target position by the guide unit holding portion, One of the ejection unit and the swing guide unit has a first fitting portion having a concave shape that opens in a lateral direction, the other of the ejection unit and the swing guide unit has a convex second fitting portion that fits into the first fitting portion when the main cover portion rotates from the open position to the closed position, the first fitting portion and the second fitting portion are formed at positions between the two support pillars in the longitudinal direction of the fixing unit, In the image forming apparatus, the second fitting portion fits into the first fitting portion, thereby restricting movement of the swing guide unit in the vertical direction and in the direction from the main cover portion toward the discharge unit.

2. a first conveyance path that is a conveyance path for the sheet from between the fixing member and the pressure member to the pair of discharge rollers; a second conveying path branched from the first conveying path, The post-fixing guide member is a first guide surface forming a partition wall of a part of the first conveying path; 2. The image forming apparatus according to claim 1, further comprising: a second guide surface formed on a rear side of the first guide surface and forming a partition wall of a part of the second transport path.

3. The body frame and a heating unit having a heater and attached to the main body frame; a fixing unit attached to the main body frame, the fixing unit including a fixing member heated by the heater and a pressure member for urging a sheet against the fixing member; an image forming apparatus including a main cover portion supported in a pivotable manner, The main body frame is two support pillars arranged along a protection side surface that is a side surface that forms one end of the fixing unit in a short side direction, extending in a vertical direction, and spaced apart in a longitudinal direction of the fixing unit; two beam portions connected to the two support columns, extending laterally, and spaced apart in the longitudinal direction of the fixing unit; the heating unit and the fixing unit are arranged side by side in a short direction of the fixing unit, the heating unit and the fixing unit are placed on the two beam portions in a state of being bridged across the two beam portions, the fixing unit is positioned in a widthwise direction of the fixing unit by being sandwiched between the heating unit and the two support pillars, the main cover portion is supported rotatably between a closed position that covers the protective side surface of the fixing unit and an open position that exposes the protective side surface of the fixing unit, the image forming apparatus, a swing guide unit having a post-fixing guide member that guides the sheet that has passed between the fixing member and the pressure member and that is supported by the main cover portion so as to be swingable up and down; the fixing unit has a guide unit holding portion formed at a position between the two support pillars in the longitudinal direction of the fixing unit, the swing guide unit has a supported portion that can come into contact with the guide unit holding portion, When the main cover portion rotates from the open position to the closed position, the supported portion moves from a position separated from the guide unit holding portion to a position in contact with the guide unit holding portion, and further the supported portion slides on the guide unit holding portion, An image forming apparatus in which the supported portion slides on the guide unit holding portion, causing the oscillating guide unit to oscillate upward due to the force it receives from the guide unit holding portion, and then the oscillating guide unit is held at a target position by the guide unit holding portion.

4. An image forming apparatus as described in Claim 3, wherein the fixing unit is formed opposite the sides of the two support pillars and has two abutment portions that abut against the sides of the two support pillars.

5. further comprising an exterior member covering the main body frame, The exterior member is an opening that opens one end of the fixing unit in the longitudinal direction; an auxiliary cover portion that can open and close the opening, The image forming apparatus according to claim 1 , wherein the fixing unit can be pulled out from the main body frame through the opening along the longitudinal direction of the fixing unit.

Images