Image forming apparatus

Abstract

Provided is an image forming apparatus capable of stably conveying a sheet even in a case where the image forming apparatus is provided with a fixing shutter. The image forming apparatus includes an apparatus main body, a fuser, a fuser slide located upstream of the fuser in a sheet conveyance direction, and a fuser guide located upstream of a heating unit in the sheet conveyance direction and having a guide conveyance surface inclined in a direction closer to the fuser slide toward downstream in the sheet conveyance direction. And a fixing shutter capable of moving to a closed position covering the upstream side of the heating unit in the sheet conveying direction and an open position opening the heating unit, the fixing shutter having a shutter conveying surface. The shutter conveyance surface is inclined in a direction closer to the fixing slide toward the downstream in the sheet conveyance direction when the fixing shutter is in the open position, so that an end portion of the shutter conveyance surface on the downstream side in the sheet conveyance direction is located closer to the fixing slide than an end portion of the guide conveyance surface on the upstream side in the sheet conveyance direction.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus. Background Art

[0002] Conventionally, as disclosed in Patent Document 1, in an image forming apparatus, in order to prevent a user's hand from touching a fixing device having a heating unit, a fixing opener / closer is provided in front of the fixing device, and the fixing opener / closer is movable between a closed position covering the heating unit and an open position exposing the heating unit.

[0003] The fixing opener / closer is configured to be normally located at a position avoiding the sheet conveyance path when in the open position.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-101165

[0007] Problems to be Solved by the Invention

[0008] However, when the conveyed sheet is curled or when the movement of the conveyed sheet is unstable, the sheet may abut against the fixing opener / closer or the like, and may not be properly conveyed, resulting in paper jams. Summary of the Invention

[0009] Therefore, in the present invention, there is provided an image forming apparatus capable of stably conveying a sheet even when a fixing opener / closer is provided.

[0010] Technical Means for Solving the Problems

[0011] The image forming apparatus for solving the above technical problems has the following features.

[0012] That is, the image forming apparatus includes: a device main body; a fixing unit having a heating unit for fixing a toner image on a conveyed sheet; a fixing chute located upstream of the fixing unit in the sheet conveying direction and forming a sheet conveying path; a fixing guide member located upstream of the heating unit in the sheet conveying direction, the fixing guide member being located on the opposite side of the fixing chute across the sheet conveying path in the sheet thickness direction to guide the sheet, and the fixing guide member having a guide member conveying surface that is inclined in a direction closer to the fixing chute as it faces downstream in the sheet conveying direction; and a fixing opener / closer located on the opposite side of the fixing chute across the sheet conveying path in the sheet thickness direction and capable of moving to a closed position covering the upstream side of the heating unit in the sheet conveying direction and an open position opening the upstream side of the heating unit in the sheet conveying direction. The fixing opener / closer has an opener / closer conveying surface. In a state where the fixing opener / closer is in the open position, the opener / closer conveying surface can guide the sheet on the upstream side of the fixing guide member in the sheet conveying direction, and in a state where the fixing opener / closer is in the open position, the opener / closer conveying surface is inclined in a direction closer to the fixing chute as it faces downstream in the sheet conveying direction, so that the end portion of the opener / closer conveying surface on the downstream side in the sheet conveying direction is closer to the fixing chute than the end portion of the guide member conveying surface on the upstream side in the sheet conveying direction.

[0013] Accordingly, a step is formed between the opener / closer conveying surface and the guide member conveying surface, where the end portion of the opener / closer conveying surface on the downstream side in the sheet conveying direction is closer to the fixing chute than the end portion of the guide member conveying surface on the upstream side in the sheet conveying direction. Therefore, when the sheet guided by the opener / closer conveying surface is taken over by the guide member conveying surface, it is possible to prevent the leading end of the conveyed sheet from getting stuck on the fixing guide member, and the sheet can be stably conveyed even when a fixing opener / closer is provided.

[0014] Moreover, in a state where the fixing opener / closer is in the open position, the end portion of the opener / closer conveying surface on the downstream side in the sheet conveying direction overlaps with the guide member conveying surface in the sheet conveying direction.

[0015] Accordingly, the sheet guided by the opener / closer conveying surface can be smoothly transferred to the guide member conveying surface, and the situation where the sheet gets stuck on the fixing guide member can be suppressed.

[0016] Moreover, the inclination angle of the opener / closer conveying surface with respect to the sheet conveying direction is greater than the inclination angle of the guide member conveying surface with respect to the sheet conveying direction.

[0017] Accordingly, a large space can be ensured between the opener / closer conveying surface and the fixing chute, and the situation where the conveyed sheet jams can be suppressed.

[0018] Moreover, in a state where the fixing opening / closing device is in the closed position, the opening / closing device conveying surface of the fixing opening / closing device faces the fuser.

[0019] Thus, when the fixing opening / closing device is in the closed position, since the opening / closing device conveying surface faces the fuser side where it is difficult for a user's hand to touch, it is possible to prevent the user's hand from touching the opening / closing device conveying surface and getting dirt attached to the opening / closing device conveying surface, and then preventing the sheet being conveyed from getting dirty due to contact with the opening / closing device conveying surface.

[0020] Moreover, the fixing opening / closing device has a shielding surface that, in a state where the fixing opening / closing device is in the closed position, covers the upstream side in the sheet conveying direction with respect to the heating unit, and the shielding surface extends in a direction intersecting the direction in which the opening / closing device conveying surface extends.

[0021] Thus, when the fixing opening / closing device is in the closed position, since the heating unit is covered by the shielding surface, it is possible to prevent the user from touching the heating unit.

[0022] Furthermore, there are provided: a cartridge that can be attached to and detached from the device main body; and an opening / closing device link provided on the device main body, connected to the fixing opening / closing device, and the opening / closing device link moves the fixing opening / closing device to the open position and the closed position in conjunction with the attachment / detachment operation of the cartridge with respect to the device main body.

[0023] Thus, there is no need for a separate operation to open and close the fixing opening / closing device, and the fixing opening / closing device can be opened and closed by the attachment / detachment operation of the cartridge with respect to the device main body.

[0024] Moreover, there is an upstream guide that can guide the sheet upstream in the sheet conveying direction with respect to the opening / closing device conveying surface of the fixing opening / closing device, and an end portion on the downstream side in the sheet conveying direction of the upstream guide is closer to the fixing chute than an end portion on the upstream side in the sheet conveying direction of the opening / closing device conveying surface.

[0025] Thus, a step is formed between the upstream guide and the opening / closing device conveying surface such that an end portion on the downstream side in the sheet conveying direction of the upstream guide is closer to the fixing chute than an end portion on the upstream side in the sheet conveying direction of the opening / closing device conveying surface. Therefore, it is possible to prevent the sheet guided by the upstream guide from getting stuck in the fixing opening / closing device when transferring to the opening / closing device conveying surface, and the sheet can be conveyed stably.

[0026] Moreover, a movable slide is provided. The movable slide is located downstream of the transfer unit that transfers an image onto a sheet in the sheet conveyance direction and upstream of the fixing unit, and is capable of moving between a first position and a second position. The second position is a position where the end portion on the downstream side in the sheet conveyance direction of the movable slide is farther from the sheet conveyance path than the first position.

[0027] Thereby, the sheet conveyed from the transfer unit can be appropriately guided to the fixing unit through the movable slide.

[0028] Moreover, the movable slide has a sheet conveyance surface for guiding the sheet. In a state where the movable slide is located at the first position, an imaginary plane obtained by extending the sheet conveyance surface of the end portion on the downstream side in the sheet conveyance direction of the movable slide passes through the fixing guide.

[0029] When the sheet guided by the sheet conveyance surface of the movable slide is a flat sheet without curling or a curled sheet that curls on the side separated from the opening / closing unit conveyance surface, the top end of the sheet guided by the movable slide abuts against the guide conveyance surface located downstream of the opening / closing unit conveyance surface. Thereby, the sheet can be guided to the fixing unit more stably.

[0030] Moreover, a perpendicular line to the opening / closing unit conveyance surface in the fixing opening / closing unit passes through the movable slide.

[0031] Thereby, the sheet conveyed from the movable slide can be appropriately guided to the fixing unit through the opening / closing unit conveyance surface.

[0032] Moreover, a drive source for moving the movable slide and a control unit for controlling the operation of the drive source are provided. After the top end of the conveyed sheet passes through the fixing unit, the control unit controls the drive source to move the movable slide from the first position to the second position.

[0033] During the period when the top end of the sheet passes through the fixing unit and the sheet is conveyed by both the fixing unit and the transfer unit, the conveyance speed of the sheet conveyed by the transfer unit is greater than the conveyance speed of the sheet conveyed by the fixing unit, and the sheet between the fixing unit and the transfer unit is deflected. Therefore, by controlling the control unit to move the movable slide to the second position separated from the sheet conveyance path, the space between the fixing unit and the transfer unit can be ensured to be large, and the situation where the deflected sheet interferes with other parts of the apparatus main body can be suppressed.

[0034] Moreover, a slide link is provided, which is connected to the drive source and moves the movable slide from the first position to the second position. The drive source is a solenoid actuator that drives the slide link. The movable slide has a sheet conveying surface for guiding a sheet, and the slide link presses the movable slide from the side of the sheet conveying surface by being driven by the drive source, thereby moving the movable slide from the first position to the second position.

[0035] Accordingly, the movable slide can be moved quickly and stably from the first position to the second position.

[0036] Moreover, the fixing guide has a guide projection located at an end in a direction orthogonal to the sheet conveying direction of the guide conveying surface and protruding toward the fixing slide side compared to the guide conveying surface. The guide projection is inclined in a direction closer to the fixing slide as it goes downstream in the sheet conveying direction, and the inclination angle of the guide projection with respect to the sheet conveying direction is greater than the inclination angle of the opener conveying surface with respect to the sheet conveying direction.

[0037] When the rear end of the conveyed sheet passes through the guide conveying surface, the rear end of the sheet sometimes jumps up. However, since the fixing guide has the guide projection, the conveyed sheet can be pressed by the guide projection, suppressing the jump-up generated at the rear end of the sheet. In this case, since the inclination angle of the guide projection is formed to be greater than the inclination angle of the opener conveying surface, even if the guide projection protrudes more than the guide conveying surface, the end of the guide projection on the upstream side in the sheet conveying direction can be positioned at a position farther from the fixing slide than the end of the opener conveying surface on the downstream side in the sheet conveying direction, suppressing the conveyed sheet from getting stuck on the guide projection.

[0038] Advantages of the Invention

[0039] According to the present invention, when a sheet is taken over from the opener conveying surface by the guide conveying surface, it is possible to suppress the top end of the conveyed sheet from getting stuck on the fixing guide and stably convey the sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic central cross-sectional view showing an image forming apparatus.

[0041] Figure 2 is a perspective view of the image forming apparatus showing a state where the front cover is in the open position.

[0042] Figure 3 is a left front perspective view showing a first main frame, a second main frame, an air duct, and a movable slide.

[0043] Figure 4It is a top view showing the first main frame, the second main frame, and the air duct.

[0044] Figure 5 It is a side cross-sectional view showing the fuser.

[0045] Figure 6 It is a perspective view showing the heating unit and the pressure roller of the fuser.

[0046] Figure 7 (a) of is a perspective view of the fuser showing the state where the shutter is in the closed position. Figure 7 (b) of is a perspective view of the fuser showing the state where the shutter is in the open position.

[0047] Figure 8 (a) of is a side view of the fuser showing the state where the shutter is in the closed position. Figure 8 (b) of is a side view of the fuser showing the state where the shutter is in the open position.

[0048] Figure 9 (a) of is a side cross-sectional view of the fuser showing the state where the shutter is in the closed position. Figure 9 (b) of is a side cross-sectional view of the fuser showing the state where the shutter is in the open position.

[0049] Figure 10 It is a perspective view showing the process cartridge.

[0050] Figure 11 It is a side view showing the process cartridge.

[0051] Figure 12 It is a side view showing the left side surface of the first main frame.

[0052] Figure 13 It is a side view showing the right side surface of the first main frame.

[0053] Figure 14 It is a side view of the link showing the state where the first boss of the abutting piece is located in the middle of the abutting piece track and the second boss is located in the front part of the abutting piece track.

[0054] Figure 15 It is a side view of the first main frame showing the state where the process cartridge is at the installation start position, the first boss of the abutting piece is located in the middle of the abutting piece track, and the second boss is located in the front part of the abutting piece track.

[0055] Figure 16 It is an enlarged side view showing the state where the drum shaft abuts against the abutting piece, a rear part of the first boss of the abutting piece is located in the rear part of the abutting piece track, and the second boss is located in the middle of the abutting piece track.

[0056] Figure 17It is an enlarged side view showing the state where the drum shaft moves from the middle part to the rear part of the cartridge track and the abutting piece is separated from the drum shaft.

[0057] Figure 18 It is a side view showing the state where the linear motion link moves backward by the pressing force from the pressing arm.

[0058] Figure 19 It is a side view of the first main frame showing the state where the processing cartridge reaches the installation position after the drum shaft is separated from the abutting piece.

[0059] Figure 20 It is a central cross-sectional view showing the image forming apparatus.

[0060] Figure 21 It is a side cross-sectional view of the area between the photosensitive drum and the fixing device in the apparatus main body, showing the state where the fixing opening / closing device is in the open position and the movable slide is in the first position.

[0061] Figure 22 It is a side cross-sectional view of the area between the photosensitive drum and the fixing device in the apparatus main body, showing the state where the fixing opening / closing device is in the closed position and the movable slide is in the second position.

[0062] Figure 23 It is a side cross-sectional view showing the positional relationship of the fixing slide, the fixing guide, and the fixing opening / closing device.

[0063] Figure 24 It is a perspective view showing the fixing guide.

[0064] Figure 25 It is a perspective view showing the fixing device, the fixing guide, the fixing opening / closing device, the air duct, and the movable slide.

[0065] Figure 26 It is a block diagram showing the drive mechanism of the movable slide.

[0066] Figure 27 It is a rear cross-sectional view of the slide link showing the state of being separated from the movable slide.

[0067] Figure 28 It is a rear cross-sectional view of the slide link showing the state of pressing the movable slide.

[0068] Symbol Explanation

[0069] 1 Image Forming Apparatus

[0070] 2 Apparatus Main Body

[0071] 6 Fixing Device

[0072] 8 Opening / Closing Link

[0073] 26 Air Duct

[0074] 28 Fixing Slide

[0075] 50 Processing Cartridge

[0076] 54 Photosensitive Drum

[0077] 54a Drum Shaft

[0078] 55 Transfer Roller

[0079] 61 Heating Unit

[0080] 64 Fixing Opener / Closer

[0081] 66 Fixing Guide

[0082] 71 Movable Slide

[0083] 71a End (on the downstream side in the sheet conveying direction of the movable slide)

[0084] 71A Sheet Conveying Surface

[0085] 71B Pressed Portion

[0086] 75 Slide Link

[0087] 95 Control Unit

[0088] 97 Solenoid

[0089] 261 Upstream Guide

[0090] 261a End (on the downstream side in the sheet conveying direction of the upstream guide)

[0091] 643 Opener / Closer Conveying Surface

[0092] 643a End (on the downstream side in the sheet conveying direction of the opener / closer conveying surface)

[0093] 643b End (on the upstream side in the sheet conveying direction of the opener / closer conveying surface)

[0094] 644 Shielding Surface

[0095] 661 Guide Conveying Surface

[0096] 661a End (on the upstream side in the sheet conveying direction of the guide conveying surface)

[0097] 662 Guide Projection

[0098] P Conveying Path

[0099] S Sheet

[0100] VL Perpendicular Line (of the opener / closer conveying surface in the fixing opener / closer)

[0101] Virtual plane (of the movable slide)

[0102] θ1 (Inclination angle of the opening / closing device conveying surface with respect to the sheet conveying direction)

[0103] θ2 (Inclination angle of the guide member conveying surface with respect to the sheet conveying direction)

[0104] θ5 (Inclination angle of the guide member protrusion with respect to the sheet conveying direction). Detailed implementation mode

[0105] Next, the implementation mode of the present invention will be described with reference to the drawings.

[0106] [Image forming device]

[0107] Figure 1 The illustrated image forming device 1 is an implementation mode of an image forming device equipped with the sheet conveying device related to the present invention, and is a laser printer that forms an image on a sheet S by an electrophotographic method.

[0108] In the following description, the Figure 1 right side in is defined as the front side of the image forming device 1, the Figure 1 left side in is defined as the rear side of the image forming device 1, the Figure 1 front side of the paper surface in is defined as the left side of the image forming device 1, the Figure 1 back side of the paper surface in is defined as the right side of the image forming device 1. Moreover, the Figure 1 upper side and lower side in are defined as the upper side and lower side of the image forming device 1 respectively.

[0109] The image forming device 1 includes a device main body 2, a paper feeding unit 3, an image forming unit 5, a fixing device 6, and a paper discharging unit 29.

[0110] The device main body 2 houses the paper feeding unit 3, the image forming unit 5, the fixing device 6, and the paper discharging unit 29. An opening 2A is opened on the front surface of the device main body 2, and the device main body 2 is provided with a front cover 21 that can open and close the opening 2A. The front cover 21 is configured to be rotatable about a rotation shaft 21a at the lower end, and by rotating about the rotation shaft 21a, it can move between a closed position for closing the opening 2A and an open position for opening the opening 2A.

[0111] The paper feeding unit 3 includes a paper feeding tray 10 for supporting the sheet S, a sheet conveying unit 30, a pair of conveying rollers 34, and a registration roller 35a. The paper feeding unit 3 is arranged at the lower part of the device main body 2 and conveys the sheet S supported by the paper feeding tray 10 to the image forming unit 5. The image forming device 1 has a conveying path P for the sheet S from the paper feeding unit 3 through the image forming unit 5 to the paper discharging unit 29. The conveying path P is an example of a sheet conveying path.

[0112] The paper supply tray 10 has a pressing plate 12 and a pressing board 13. The pressing plate 12 is a plate-like member that supports the sheet S from below. The pressing plate 12 can rotate around the rotation fulcrum 12a at the rear end, and by rotating around the rotation fulcrum 12a, it can move up and down between the lowered position and the raised position. The pressing board 13 is located below the pressing plate 12 and can cause the pressing plate 12 to move up and down between the lowered position and the raised position.

[0113] The sheet conveying unit 30 is a conveying mechanism that separates and removes the sheets S supported on the paper supply tray 10 one by one and conveys them to the image forming unit 5, and includes a paper feed roller 31, a separating roller 32, and a separating pad 33.

[0114] The paper feed roller 31 is a roller for feeding the sheet S supported on the paper supply tray 10 to the separating roller 32. The separating roller 32 is arranged on the downstream side in the sheet conveying direction compared with the paper feed roller 31, and the separating pad 33 is arranged opposite to the separating roller 32 and is biased toward the separating roller 32.

[0115] The sheet S fed from the paper feed roller 31 to the separating roller 32 is separated one by one between the separating roller 32 and the separating pad 33. The sheets S separated one by one are fed to the conveying path P.

[0116] The sheet S sent out to the conveying path P is conveyed to the image forming unit 5 through the conveying roller pair 34, the registration roller 35a, and the pressing roller 35b arranged opposite to the registration roller 35a. The registration roller 35a restricts the movement of the leading end of the conveyed sheet S and, after temporarily stopping it, conveys the sheet S to the image forming unit 5 at a specified timing.

[0117] The image forming apparatus 1 has a post-registration sensor 98 for detecting the sheet S conveyed along the conveying path P downstream of the registration roller 35a in the sheet conveying direction. The post-registration sensor 98 can be configured such that, for example, when the leading end of the sheet S passes through the post-registration sensor 98, it detects the leading end of the sheet S and conducts, and when the trailing end of the sheet S passes through the post-registration sensor 98, it detects the trailing end of the sheet S and disconnects.

[0118] The image forming unit 5 is arranged on the downstream side in the sheet conveying direction compared with the paper supply unit 3, and forms an image on the sheet S conveyed from the paper supply unit 3. The image forming unit 5 includes a processing cartridge 50 for transferring an image to the surface of the sheet S conveyed from the paper supply unit 3, a transfer roller 55 arranged opposite to the photosensitive drum 54 of the processing cartridge 50, and an exposure unit 56 for exposing the surface of the photosensitive drum 54. The processing cartridge 50 is an example of a cartridge that can be attached to and detached from the apparatus main body.

[0119] The processing cartridge 50 is arranged above the paper supply unit 3 in the apparatus main body 2, and includes a developer storage chamber 51, a supply roller 52, a developing roller 53, a photosensitive drum 54, etc. The processing cartridge 50 supports the pressing roller 35b.

[0120] The processing cartridge 50 includes a drum cartridge having a photosensitive drum 54 and a developing cartridge mounted on the drum cartridge and having a developing roller 53, and is detachably mounted on the apparatus main body 2. In this case, the processing cartridge 50 is mounted on the apparatus main body 2 by integrally inserting the drum cartridge and the developing cartridge mounted on the drum cartridge into the apparatus main body 2, and is detached from the apparatus main body 2 by integrally pulling out the drum cartridge and the developing cartridge mounted on the drum cartridge from the apparatus main body 2.

[0121] The processing cartridge 50 is an example of a cartridge, and can have a structure including at least one of a photosensitive drum, a developing roller, and a toner container. When the front cover 21 is in the open position, the processing cartridge 50 can be attached to and detached from the apparatus main body 2.

[0122] The photosensitive drum 54 is arranged in a posture such that the axis X extends in the left-right direction in a state where the processing cartridge 50 is mounted on the apparatus main body 2. The photosensitive drum 54 has a metallic drum shaft 54a extending in the direction of the axis X. The photosensitive drum 54 rotates about the drum shaft 54a.

[0123] In the present embodiment, the processing cartridge 50 includes a drum cartridge having a photosensitive drum 54 and a developing cartridge mounted on the drum cartridge and having a developing roller 53, but may also have a structure including a cartridge having a photosensitive drum 54 and a developing roller 53 and a toner cartridge mounted on the cartridge and accommodating toner.

[0124] Moreover, in the image forming apparatus, it can be configured such that the drum cartridge having the photosensitive drum 54 and the developing cartridge having the developing roller 53 are respectively mounted on the apparatus main body 2. That is, the processing cartridge 50 can be configured to include at least one of a photosensitive drum, a developing roller, and a toner container, and to be detachably mounted on the apparatus main body.

[0125] The exposure unit 56 includes a laser diode, a polygon mirror, a lens, a mirror, etc., and exposes the surface of the photosensitive drum 54 by irradiating laser light onto the photosensitive drum 54 according to the image data input to the image forming apparatus 1.

[0126] Toner serving as a developer is accommodated in the developer accommodating chamber 51. The toner accommodated in the developer accommodating chamber 51 is sent to the supply roller 52 while being agitated by an agitation member (not shown). The supply roller 52 further supplies the toner sent from the developer accommodating chamber 51 to the developing roller 53.

[0127] The developing roller 53 is arranged in close contact with the supply roller 52, and holds the toner supplied from the supply roller 52 and positively charged through a sliding contact member (not shown). Moreover, a developing bias is applied to the developing roller 53 by a bias applying mechanism (not shown).

[0128] The photosensitive drum 54 is disposed adjacent to the developing roller 53. After the surface of the photosensitive drum 54 is uniformly charged by a charger (not shown), it is exposed by the exposure unit 56. The exposed portion of the photosensitive drum 54 has a lower potential than other portions, and an electrostatic latent image based on image data is formed on the photosensitive drum 54. Then, by supplying positively charged toner to the surface of the photosensitive drum 54 on which the electrostatic latent image is formed from the developing roller 53, the electrostatic latent image is developed into a toner image.

[0129] The transfer roller 55 is disposed opposite to the photosensitive drum 54 and is applied with a transfer bias by a bias application mechanism (not shown). In a state where the transfer bias is applied to the surface of the transfer roller 55, while sandwiching the sheet S between the photosensitive drum 54 on which the toner image is formed and the transfer roller 55 and conveying it, the toner image on the surface of the photosensitive drum 54 is transferred to the surface of the sheet S. The photosensitive drum 54 and the transfer roller 55 of the processing cartridge 50 constitute a transfer unit for transferring an image onto the sheet S. The sheet S onto which the toner image is transferred is conveyed to the fixing unit 6.

[0130] The fixing unit 6 includes a heating unit 61 and a pressure roller 62, and fixes the image transferred onto the sheet S by the processing cartridge 50. The heating unit 61 is heated by supplying power from a power source (not shown). The heating unit 61 is an example of a heating portion, and the pressure roller 62 is an example of a pressing portion. The pressure roller 62 is disposed opposite to the heating unit 61. One of the heating unit 61 and the pressure roller 62 is biased relative to the other by a biasing mechanism (not shown), and the heating unit 61 and the pressure roller 62 are in close contact with each other.

[0131] When the sheet S onto which the toner image is transferred is sent to the fixing unit 6, the sheet S is sandwiched between the heating unit 61 and the pressure roller 62 and conveyed while being heated, so that the toner image is fixed on the sheet S. In this way, the fixing unit 6 fixes the toner image transferred onto the conveyed sheet S.

[0132] The paper discharge unit 29 is located on the downstream side in the sheet conveying direction with respect to the image forming unit 5, and discharges the sheet S on which an image is formed by the image forming unit 5 to the outside of the image forming apparatus 1. The paper discharge unit 29 includes a pair of paper discharge rollers 291 and a paper discharge tray 292. The pair of paper discharge rollers 291 is configured to be able to discharge the sheet S conveyed along the conveying path P from the fixing unit 6 to the outside of the apparatus main body 2. The paper discharge tray 292 is formed on the upper surface of the apparatus main body 2 and supports the sheet S discharged to the outside of the apparatus main body 2 by the pair of paper discharge rollers 291.

[0133] As Figures 2 to 4As shown, the apparatus main body 2 includes a first main body frame 24 and a second main body frame 25 that are disposed separately from each other in the left-right direction. The first main body frame 24 is located at the right end portion of the apparatus main body 2, and the second main body frame 25 is located at the left end portion of the apparatus main body 2. The first main body frame 24 extends in the front-rear direction and the up-down direction, and is disposed in a posture where the plate surface faces the left-right direction. The second main body frame 25 extends in the front-rear direction and the up-down direction, and is disposed in a posture where the plate surface faces the left-right direction.

[0134] The processing cartridge 50 and the fixing device 6 are disposed between the first main body frame 24 and the second main body frame 25. The first main body frame 24 is disposed on the right side of the processing cartridge 50 and the fixing device 6, and the second main body frame 25 is disposed on the left side of the processing cartridge 50 and the fixing device 6. The processing cartridge 50 is supported by the first main body frame 24 and the second main body frame 25 in a detachable manner.

[0135] The first main body frame 24 supports a fan 27 that discharges the air inside the apparatus main body 2 to the outside of the apparatus main body 2. The second main body frame 25 supports a control board 951 on which electronic components such as a CPU 951a are mounted. The control board 951 constitutes a control unit 95 (refer to Figure 26 ).

[0136] An air duct 26 extending in the left-right direction is disposed between the first main body frame 24 and the second main body frame 25. The air duct 26 is provided across the first main body frame 24 and the second main body frame 25. The right end portion of the air duct 26 is supported by the first main body frame 24, and the left end portion of the air duct 26 is supported by the second main body frame 25. The air duct 26 is located between the processing cartridge 50 and the fixing device 6 in the front-rear direction.

[0137] The air duct 26 is disposed at a position overlapping with the fan 27 when viewed from the left-right direction. Air can flow through the air duct 26. The air duct 26 guides the air inside the apparatus main body 2 to the fan 27.

[0138] [Fixing device]

[0139] As Figure 5 , Figure 6 shown, the heating unit 61 of the fixing device 6 includes a heater 611, a holder 612, a retaining member 613, and a belt 614. The heater 611 is a flat heater extending in the left-right direction. The heater 611 has a first surface 611A and a second surface 611B opposite to the first surface 611A, and the first surface 611A is supported by the holder 612.

[0140] The cage 612 is made of, for example, a resin member, and has a guide surface 612a and a support wall 612b. The guide surface 612a guides the belt 614 in contact with the inner peripheral surface 614a of the belt 614. The support wall 612b has a support surface 612A for supporting the heater 611. The support surface 612A of the support wall 612b abuts against the first surface 611A of the heater 611. The holder 613 is a member that supports the cage 612, and is formed by bending a plate material having a higher rigidity than the cage 612, such as a steel plate, into a substantially U-shape when viewed in cross section.

[0141] The belt 614 is a seamless belt having heat resistance and flexibility, and has a metal base tube made of a metal such as stainless steel and a fluororesin layer covering the metal base tube. The heater 611, the cage 612, and the holder 613 are arranged inside the belt 614. The belt 614 is configured to rotate around the heater 611, the cage 612, and the holder 613. The inner peripheral surface 614a of the belt 614 is in contact with the heater 611.

[0142] The pressure roller 62 has a metal shaft 62A and an elastic layer 62B covering the shaft 62A. The pressure roller 62 presses against the heater 611 via the belt 614. The pressure roller 62 forms a clamping portion NP for heating and pressing the sheet S by sandwiching the belt 614 between the pressure roller 62 and the heater 611. That is, the pressure roller 62 forms the pressure roller 62 and the clamping portion NP, and in the clamping portion NP, the sheet S is heated and pressed together with the heater 611.

[0143] The pressure roller 62 is configured to be rotationally driven by being transmitted with the driving force from the motor provided in the image forming apparatus 1. The pressure roller 62 is rotationally driven, and thereby the belt 614 is driven to rotate idly by the frictional force with the belt 614 or the sheet S sandwiched by the clamping portion NP. As a result, the sheet S on which the toner image is transferred is conveyed between the pressure roller 62 and the heated belt 614, and the toner image is thermally fixed.

[0144] As Figure 1 , Figures 7 to 9 shown, the fixing device 6 has a fixing frame 63 covering the heating unit 61 and the pressure roller 62 and a fixing opener / closer 64 supported by the fixing frame 63. The fixing frame 63 holds the heating unit 61 and the pressure roller 62. The fixing frame 63 covers the periphery of the heating unit 61 and the pressure roller 62, and has a first opening 63a formed on the upstream side in the sheet conveying direction of the heating unit 61 and the pressure roller 62 and a second opening 63b formed on the downstream side in the sheet conveying direction of the heating unit 61 and the pressure roller 62.

[0145] The fixing frame 63 has an upper frame 63A and a lower frame 63B. The upper frame 63A is located above the lower frame 63B. The upper frame 63A covers the heating unit 61, and the lower frame 63B covers the pressure roller 62.

[0146] The fixing opener / closer 64 is located on the upstream side in the sheet conveying direction of the first opening 63a in the fixing frame 63, and has a rotating shaft 641 extending in the left-right direction and a connecting shaft 642 protruding toward a direction parallel to the rotating shaft 641. The rotating shaft 641 is rotatably supported by the fixing frame 63. The rotating shaft 641 is provided at the left and right end portions of the fixing opener / closer 64, and the connecting shaft 642 protrudes rightward from the right end portion of the fixing opener / closer 64.

[0147] The fixing opener / closer 64 is configured to be rotatable about the rotating shaft 641, and by rotating about the rotating shaft 641, it can be in a closed position ( Figure 7 in (a) of Figure 8 in (a) of Figure 9 (the position shown in (a)) that closes the first opening 63a and an open position ([[]] Figure 7 in (b) of Figure 8 in (b) of Figure 9 (the position shown in (b)) that opens the first opening 63a) and move between them. When the fixing opener / closer 64 is in the closed position, the clamping portion NP of the heating unit 61 and the pressure roller 62 is covered by the fixing opener / closer 64, and when the fixing opener / closer 64 is in the open position, the clamping portion NP of the heating unit 61 and the pressure roller 62 is exposed to the outside of the fixing frame 63 through the first opening 63a.

[0148] Moreover, when the fixing opener / closer 64 is in the closed position, it covers the upstream side in the sheet conveying direction of the heating unit 61, and when in the open position, it opens the upstream side in the sheet conveying direction of the heating unit 61. That is to say, the fixing opener / closer 64 can move to a closed position that covers the upstream side in the sheet conveying direction of the heating unit 61 and an open position that opens the upstream side in the sheet conveying direction of the heating unit 61.

[0149] In addition, in the present embodiment, the fixing device 6 includes a pressure roller 62 and a heating unit 61 having a heater 611 and a belt 614, but the fixing device 6 may also be configured to include a heating roller with a built-in heater and a pressure roller pressed against the heating roller. Moreover, the fixing device 6 may also be configured to include a heating roller with a built-in heater and a pressure belt pressed against the heating roller by an elastic member.

[0150] [Drum shaft]

[0151] As Figure 10 、 Figure 11As shown, the drum shaft 54a of the photosensitive drum 54 protrudes rightward from the right end portion of the processing cartridge 50 in the axial direction X. That is, the drum shaft 54a protrudes toward the first main body frame 24 side in the axial direction X.

[0152] [First main body frame]

[0153] As Figure 12 、 Figure 13 shown, the first main body frame 24 has a cartridge rail 241 and a contact piece rail 242. The cartridge rail 241 is formed in a groove shape open on the left side. The cartridge rail 241 extends in the front-rear direction and is inclined in a direction that descends as it goes from the front to the rear.

[0154] The drum shaft 54a of the photosensitive drum 54 can enter the cartridge rail 241, and when the processing cartridge 50 is installed in the apparatus main body 2 and when the processing cartridge 50 is detached from the apparatus main body 2, the cartridge rail 241 guides the drum shaft 54a. The drum shaft 54a guided by the cartridge rail 241 enters the cartridge rail 241 from the left side. In addition, the processing cartridge 50 is installed in the apparatus main body 2 from the front to the rear and is detached from the apparatus main body 2 from the rear to the front.

[0155] The contact piece rail 242 is formed in a groove shape open on the right side. The contact piece rail 242 extends in the front-rear direction and is inclined in a direction that descends as it goes from the front to the rear. The contact piece rail 242 is located on the right side in the left-right direction compared to the cartridge rail 241.

[0156] The cartridge rail 241 has a front portion 241a located in the front, a rear portion 241c located in the rear, and a middle portion 241b located between the front portion 241a and the rear portion 241c. The contact piece rail 242 has a front portion 242a located in the front, a rear portion 242c located in the rear, and a middle portion 242b located between the front portion 242a and the rear portion 242c.

[0157] The middle portion 241b of the cartridge rail 241 overlaps with the middle portion 242b of the contact piece rail 242 and communicates with each other. A through hole 24C that penetrates the front frame 24A in the left-right direction is formed by the middle portion 241b and the middle portion 242b. When the processing cartridge 50 is installed in the apparatus main body 2 and when the processing cartridge 50 is detached from the apparatus main body 2 by the cartridge rail 241, the drum shaft 54a enters the through hole 24C.

[0158] The front portion 242a of the contact piece rail 242 and the front portion 241a of the cartridge rail 241 are located above, and the rear portion 242c of the contact piece rail 242 is located above compared to the rear portion 241c of the cartridge rail 241.

[0159] [Linkage]

[0160] As Figure 8 、 Figure 14 、 Figure 15As shown, the apparatus main body 2 has an opening / closing link 8 that can abut against the processing cartridge 50 to move the fixing opening / closing device 64 between an open position and a closed position. The opening / closing link 8 is connected to the fixing opening / closing device 64.

[0161] When the processing cartridge 50 is installed in the apparatus main body 2, the opening / closing link 8 abuts against the processing cartridge 50, causing the fixing opening / closing device 64 to move from the closed position to the open position. When the processing cartridge 50 is removed from the apparatus main body 2, the opening / closing link 8 abuts against the processing cartridge 50, causing the fixing opening / closing device 64 to move from the open position to the closed position. That is, the opening / closing link 8 is structured to move the fixing opening / closing device 64 between the open position and the closed position in conjunction with the loading and unloading operation of the processing cartridge 50 relative to the apparatus main body 2.

[0162] The opening / closing link 8 has an abutting piece 80, a first rotating link 81, a linear motion link 82, a second rotating link 83, a third rotating link 84, an opening / closing link 85, and a spiral spring 86.

[0163] The abutting piece 80 moves while abutting against the drum shaft 54a of the photosensitive drum 54. The abutting piece 80 is slidably fitted in the abutting piece rail 242, and the abutting piece rail 242 guides the abutting piece 80 that moves while abutting against the drum shaft 54a.

[0164] The abutting piece 80 has a main body portion 801, a connecting portion 802, a first boss 803, and a second boss 804. The main body portion 801 is formed of a plate-like member with a plate surface facing the left and right directions. The connecting portion 802 is a protrusion that protrudes rightward from the right surface of the main body portion 801.

[0165] The first boss 803 and the second boss 804 are protrusions that protrude leftward from the left surface of the main body portion 801. The first boss 803 and the second boss 804 enter the abutting piece rail 242 of the first main frame 24 from the right side and are guided by the abutting piece rail 242.

[0166] The second boss 804 is located upstream in the installation direction of the processing cartridge 50 compared to the first boss 803. In addition, the installation direction refers to the direction in which the processing cartridge 50 moves toward the installation position when the processing cartridge 50 is installed in the apparatus main body 2.

[0167] When the processing cartridge 50 is installed in the apparatus main body 2, the first boss 803 abuts against the drum shaft 54a. When the processing cartridge 50 is removed from the apparatus main body 2, the second boss 804 abuts against the drum shaft 54a.

[0168] When the first boss 803 is located at the middle portion 242b (through hole 24C) of the abutting piece rail 242, it abuts against the drum shaft 54a of the processing cartridge 50 mounted on the apparatus main body 2. Further, when the second boss 804 is located at the middle portion 242b (through hole 24C) of the abutting piece rail 242, it abuts against the drum shaft 54a of the processing cartridge 50 detached from the apparatus main body 2.

[0169] The first rotating link 81 is a substantially linear member rotatably connected to the abutting piece 80. The first rotating link 81 has: a fitting portion 811 located at the front end for rotatably fitting the connecting portion 802 of the abutting piece 80; and a boss 812 located at the rear end and protruding leftward. The first rotating link 81 is arranged in an inclined posture where the fitting portion 811 is above and in front of the boss 812. By fitting the connecting portion 802 with the fitting portion 811, the first rotating link 81 is connected to the abutting piece 80, and the first rotating link 81 rotates following the movement of the abutting piece 80.

[0170] The linear motion link 82 is rotatably connected to the first rotating link 81 and is a substantially linear member extending in the front-rear direction. The linear motion link 82 has: a fitting portion 821 located at the front end for rotatably fitting the boss 812 of the first rotating link 81; and a connecting hole 822 located at the rear end. By fitting the boss 812 with the fitting portion 821, the linear motion link 82 is connected to the first rotating link 81, and the linear motion link 82 linearly moves in the front-rear direction following the rotation of the first rotating link 81.

[0171] The second rotating link 83 is connected to the linear motion link 82 and is supported by the first main frame 24. The second rotating link 83 has: a supporting portion 831 rotatably supported by the first main frame 24, a first arm 832 extending substantially downward from the supporting portion 831, and a second arm 833 extending substantially upward from the supporting portion 831. A engaging pin 832a protruding leftward is formed at the tip of the first arm 832, and a connecting hole 833a is formed at the tip of the second arm 833.

[0172] The engaging pin 832a of the first arm 832 enters the connecting hole 822 of the linear motion link 82 from the right and engages with the connecting hole 822 following the movement of the linear motion link 82 in the front-rear direction. By engaging the engaging pin 832a with the connecting hole 822, the second rotating link 83 is connected to the linear motion link 82, and the second rotating link 83 rotates about the supporting portion 831 following the movement of the linear motion link 82.

[0173] The third rotating link 84 is connected to the second rotating link 83 and is supported by a support shaft 65 of the fixing device 6 in a rotatable manner. The third rotating link 84 has: a support portion 841 supported by the support shaft 65 in a rotatable manner, an engagement pin 842 protruding rightward from the support portion 841, an operation cam 843 formed at a phase different from that of the engagement pin 842 in the circumferential direction of the support portion 841, and a connection hole 844 formed in the operation cam 843. The connection hole 844 penetrates the operation cam 843 in the left-right direction.

[0174] The engagement pin 842 of the third rotating link 84 enters the connection hole 833a of the second rotating link 83 from the left and engages with the connection hole 833a following the rotation of the second rotating link 83. By the engagement of the engagement pin 842 with the connection hole 833a, the third rotating link 84 is connected to the second rotating link 83, and the third rotating link 84 rotates about the support shaft 65 following the rotation of the second rotating link 83.

[0175] As Figure 7 , Figure 8 shown, the opening / closing link 85 is connected to the third rotating link 84 and is supported by a support shaft 65 of the fixing device 6 in a rotatable manner. The opening / closing link 85 moves following the movement of the third rotating link 84, causing the fixing opening / closing device 64 of the fixing device 6 to move between a closed position and an open position. The opening / closing link 85 is located at the right end of the fixing device 6 and has a support portion 851, an arm portion 852, an engagement portion 853, and an engagement pin 854.

[0176] The support portion 851 is supported by a support shaft 65 protruding rightward from the right end of the fixing frame 63 in a rotatable manner. The arm portion 852 is an arm member extending forward from the support portion 851. The engagement portion 853 is located at the front end of the arm portion 852 and has an engagement hole 853a having an oval shape that is long in the front-rear direction. A connection shaft 642 protruding rightward from the right end of the fixing opening / closing device 64 engages with the engagement hole 853a.

[0177] The opening / closing link 85 can rotate about the support portion 851 in the direction of the up-and-down movement of the engagement portion 853. In a state where the opening / closing link 85 rotates and the engagement portion 853 moves downward, the fixing opening / closing device 64 moves to the closed position (refer to Figure 7 (a) of Figure 8 ), and in a state where the opening / closing link 85 rotates and the engagement portion 853 moves upward, the fixing opening / closing device 64 moves to the open position (refer to Figure 7 (b) of Figure 8 ).

[0178] The engagement pin 854 protrudes rightward from the end of the arm portion 852 on the side of the support portion 851. The engagement pin 854 of the opening / closing link 85 enters the connection hole 844 of the third rotating link 84 from the left.

[0179] The coil spring 86 is supported on the support portion 841 of the third rotating link 84. The coil spring 86 has a shank portion 861. The shank portion 861 extends from the inner diameter side to the outer diameter side of the connection hole 844 and enters the connection hole 844.

[0180] The shank portion 861 is located above the engagement pin 854 within the connection hole 844. The coil spring 86 can rotate along with the rotation of the third rotating link 84. An edge portion at the lower end of the connection hole 844 in the operation cam 843 of the third rotating link 84 forms an engagement surface 844a. The engagement surface 844a is located below the engagement pin 854.

[0181] By rotating the third rotating link 84 toward the side moving upward with respect to the operation cam 843, the engagement surface 844a of the connection hole 844 engages with the engagement pin 854. By rotating the third rotating link 84 toward the side moving downward with respect to the operation cam 843, the shank portion 861 of the coil spring 86 engages with the engagement pin 854.

[0182] By the engagement pin 854 engaging with the shank portion 861 or the engagement surface 843a, the opening / closing link 85 is connected to the third rotating link 84 and moves along with the rotation of the third rotating link 84, causing the fixing opening / closing device 64 to move between the closed position and the open position.

[0183] In the image forming apparatus 1, when the processing cartridge 50 is mounted to or detached from the apparatus main body 2, the driving force is transmitted to the fixing opening / closing device 64 via the opening / closing device link 8 by the abutting piece 80 of the opening / closing device link 8 abutting against the drum shaft 54a and moving along the abutting piece track 242, and the fixing opening / closing device 64 moves between the closed position and the open position.

[0184] In the present embodiment, the opening / closing device link 8 is configured to include the abutting piece 80, the first rotating link 81, the linear motion link 82, the second rotating link 83, the third rotating link 84, the opening / closing link 85, and the coil spring 86, but is not limited thereto, and may also be constituted by a single link that opens and closes the fixing opening / closing device 64 by being connected to the fixing opening / closing device 64 and abutting against the processing cartridge 50. Moreover, the operating state of the opening / closing device link 8 is not limited to rotation or sliding, and the fixing opening / closing device 64 may be opened and closed with an appropriate action corresponding to the insertion and removal of the processing cartridge 50.

[0185] [Pressing portion]

[0186] As Figure 14As shown, the apparatus main body 2 is provided with a pressing portion 9. During the process in which the fuser opening / closing link 8 moves the fuser opening / closing unit 64 from the closed position to the open position, before the fuser opening / closing unit 64 moves to the open position, the pressing portion 9 presses the fuser opening / closing link 8 in the direction in which the fuser opening / closing unit 64 becomes the open position. Moreover, by pressing the fuser opening / closing link 8, the pressing portion 9 restricts the movement of the fuser opening / closing link 8 that moves the fuser opening / closing unit 64 to the open position or the closed position.

[0187] The pressing portion 9 includes a pressing spring 92 and a pressing arm 91 that is pressed by the pressing spring 92 and abuts against the upper surface 82A of the linear motion link 82. The pressing spring 92 presses the tip of the pressing arm 91 toward the upper surface 82A side of the linear motion link 82.

[0188] The upper surface 82A of the linear motion link 82 has a link protrusion 823 that protrudes upward. The link protrusion 823 is formed in a mountain shape having a first pressed surface 823a, a second pressed surface 823b, and a third pressed surface 823c.

[0189] The first pressed surface 823a is located at the apex portion of the mountain shape and extends in the horizontal direction. The second pressed surface 823b is located in front of the first pressed surface 823a and is formed as an inclined surface that rises as it faces the rear. The third pressed surface 823c is located behind the first pressed surface 823a and is formed as an inclined surface that descends as it faces the rear.

[0190] The linear motion link 82 can be located at a position where the pressing arm 91 presses the first pressed surface 823a, a position where the pressing arm 91 presses the second pressed surface 823b, and a position where the pressing arm 91 presses the third pressed surface 823c by moving in the front-rear direction.

[0191] Since the first pressed surface 823a is a surface that extends in the horizontal direction, when the pressing arm 91 presses the first pressed surface 823a from above, the pressing force of the pressing arm 91 does not act in both the rearward direction and the forward direction.

[0192] Since the second pressed surface 823b is a surface that slopes upward from the bottom in the rearward direction, when the pressing arm 91 presses the second pressed surface 823b from above, the pressing force of the pressing arm 91 acts in the rearward direction. Moreover, in a state where the pressing arm 91 presses the second pressed surface 823b from above, the forward movement of the linear motion link 82 is restricted.

[0193] The third pressed surface 823c is a surface that slopes downward from above in the rearward direction. Therefore, when the pressing arm 91 presses the third pressed surface 823c from above, the pressing force of the pressing arm 91 acts in the forward direction. Moreover, in a state where the pressing arm 91 presses the third pressed surface 823c from above, the rearward movement of the linear motion link 82 is restricted.

[0194] In the present embodiment, the pressing portion 9 has a pressing spring 92 and a pressing arm 91 that is pressed by the pressing spring 92 and abuts against the upper surface 82A of the linear motion link 82. However, it is not limited thereto, and as long as it is a structure of the pressing and closing link 8, it may not be in the shape of a spring or an arm.

[0195] [Operation of the link]

[0196] Next, the operation of the opening and closing link 8 will be described.

[0197] (Operation when the processing cartridge is installed)

[0198] When the processing cartridge 50 is installed on the apparatus main body 2, after the drum shaft 54a enters the front portion 241a of the cartridge rail 241 (see Figure 15 ), it enters the middle portion 241b (through hole 24C) and abuts against the first boss 803 of the abutting piece 80. As Figure 16 shown, the abutting piece 80 that abuts against the drum shaft 54a is pressed by the drum shaft 54a and moves downstream in the installation direction of the processing cartridge 50.

[0199] When the abutting piece 80 moves, the first rotating link 81 moves rearward while rotating in a direction in which the inclination angle relative to the horizontal direction becomes smaller. When the first rotating link 81 rotates and moves, the linear motion link 82 connected to the first rotating link 81 moves linearly rearward.

[0200] When the linear motion link 82 moves rearward, the engagement hole 822 of the linear motion link 82 engages with the engagement pin 832a of the second rotating link 83, and the second rotating link 83 rotates in the direction in which the engagement pin 832a moves rearward. When the second rotating link 83 rotates, the engagement hole 833a of the second rotating link 83 engages with the engagement pin 842 of the third rotating link 84, and the third rotating link 84 rotates in the direction in which the engagement pin 842 moves forward.

[0201] When the third rotating link 84 rotates, the engagement surface 844a of the engagement hole 844 in the operation cam 843 engages with the engagement pin 854 of the opening and closing link 85 from below. By the engagement of the engagement surface 844a of the engagement hole 844 with the engagement pin 854, the opening and closing link 85 rotates in the direction in which the engaging portion 853 moves upward, and the fixing opening and closing device 64 moves from the closed position to the open position.

[0202] As shown Figure 17 in FIG. 2, the drum shaft 54a that moves the contact piece 80 rearward at the middle portion 241b (through hole 24C) of the cartridge rail 241 moves from the middle portion 241b to the rear portion 241c of the cartridge rail 241 and separates from the contact piece 80.

[0203] As shown Figure 18 in FIG. 3, after the drum shaft 54a contacts the contact piece 80 and the linear motion link 82 moves rearward, in a state where the drum shaft 54a is separated from the contact piece 80, the pressing arm 91 contacts the second pressed surface 823b of the linear motion link 82.

[0204] After the contact piece 80 is separated from the drum shaft 54a, the drum shaft 54a does not move the contact piece 80. However, since the pressing arm 91 contacts the second pressed surface 823b, a pressing force in the direction toward the second position is applied to the linear motion link 82 from the pressing arm 91, and the linear motion link 82 moves rearward.

[0205] As shown Figure 8 in FIG. 4(b), when the linear motion link 82 is moved rearward by the pressing force from the pressing arm 91, the opening and closing link 85 rotates in the direction of moving upward toward the engaging portion 853, and the fixing opening and closing device 64 moves to the open position. As shown Figure 19 in FIG. 5, when the processing cartridge 50 is in the state of being mounted on the apparatus main body 2, the drum shaft 54a separated from the contact piece 80 moves to the mounting position at the rear end of the rear portion 241c of the cartridge rail 241.

[0206] (Operation when the processing cartridge is removed)

[0207] The opening and closing link 8 operates in the reverse direction to the operation when the processing cartridge 50 is mounted when removing the processing cartridge 50.

[0208] When the processing cartridge 50 in the mounting position shown Figure 19 in FIG. 6 is removed forward from the apparatus main body 2, the drum shaft 54a moves to the downstream side in the removal direction in the rear portion 241c of the cartridge rail 241. In addition, the removal direction is the direction in which the processing cartridge 50 moves outside the apparatus main body 2 when the processing cartridge 50 is pulled out from the apparatus main body 2 when removing the processing cartridge 50 from the apparatus main body 2. As shown Figure 16 in FIG. 7, when the drum shaft 54a moving in the cartridge rail 241 reaches the middle portion 241b (through hole 24C), the drum shaft 54a contacts the second boss 804 of the contact piece 80.

[0209] The abutting piece 80 that abuts against the drum shaft 54a moves to the downstream side in the separating direction of the processing cartridge 50 in the middle part 242b (through hole 24C). When the abutting piece 80 moves, the first rotating link 81 rotates in a direction in which the inclination angle with respect to the horizontal direction increases and moves forward, and the linear motion link 82 moves linearly forward.

[0210] When the linear motion link 82 moves, the engaging hole 822 of the linear motion link 82 engages with the engaging pin 832a of the second rotating link 83, and the second rotating link 83 rotates in the direction in which the engaging pin 832a moves forward. When the second rotating link 83 rotates, the engaging hole 833a of the second rotating link 83 engages with the engaging pin 842 of the third rotating link 84, and the third rotating link 84 rotates in the direction in which the engaging pin 842 moves backward.

[0211] When the third rotating link 84 rotates, the spiral spring 86 rotates along with the rotation of the third rotating link 84, and the handle portion 861 of the spiral spring 86 engages with the engaging pin 854 of the opening / closing link 85 from above. By the engagement of the handle portion 861 with the engaging pin 854, the opening / closing link 85 rotates in the direction in which the engaging portion 853 moves downward. Thereby, the fixing open / close device 64 moves from the open position to the closed position side. In a state where the processing cartridge 50 is separated from the apparatus main body 2, the fixing open / close device 64 is located at the closed position.

[0212] In this way, the open / close device link 8 connected to the fixing open / close device 64 is configured to move the fixing open / close device 64 to the open position and the closed position in conjunction with the loading and unloading operation of the processing cartridge 50 with respect to the apparatus main body 2. Thereby, without performing a separate operation for opening and closing the fixing open / close device 64, the fixing open / close device 64 can be opened and closed by the loading and unloading operation of the processing cartridge 50 with respect to the apparatus main body 2.

[0213] In addition, in the present embodiment, the fixing open / close device 64 is opened and closed by the abutment of the drum shaft 54a of the processing cartridge 50 against the open / close device link 8, but it is not limited thereto, and a structure in which other parts of the processing cartridge 50 abut against the open / close device link 8 may also be used.

[0214] [Position relationship of fixing slide, fixing guide, and fixing open / close device]

[0215] As Figures 20 to 22 shown, the apparatus main body 2 has a fixing slide 28 and a fixing guide 66.

[0216] The fixing chute 28 is located upstream of the fixing unit 6 in the sheet conveying direction and forms the lower side of the conveying path P of the sheet S. The fixing chute 28 is supported by the lower frame 63B of the fixing frame 63. The fixing chute 28 is located below the conveying path P. The fixing chute 28 has a sheet conveying surface 28A facing upward, and the sheet conveying surface 28A guides the lower side of the sheet S conveyed along the conveying path P.

[0217] At a position upstream of the heating unit 61 of the fixing unit 6 in the sheet conveying direction, the fixing guide 66 is located on the opposite side of the fixing chute 28 across the conveying path P in the thickness direction of the sheet S conveyed along the conveying path P. The fixing guide 66 is located above the conveying path P and guides the upper side of the sheet S conveyed along the conveying path P. The fixing guide 66 is supported by the upper frame 63A of the fixing frame 63.

[0218] The fixing guide 66 has a guide conveying surface 661 facing downward. The guide conveying surface 661 is an inclined surface that is inclined in a direction closer to the fixing chute 28 as it goes downstream in the sheet conveying direction. When the sheet S conveyed downstream in the sheet conveying direction from the photosensitive drum 54 abuts against the guide conveying surface 661, the sheet S is guided by the guide conveying surface 661 to the first opening 63a of the fixing frame 63.

[0219] At a position upstream of the fixing guide 66 in the sheet conveying direction, the fixing opener / closer 64 is located on the opposite side of the fixing chute 28 across the conveying path P in the thickness direction of the sheet S conveyed along the conveying path P.

[0220] The fixing opener / closer 64 has an opener / closer conveying surface 643 that can convey the sheet S on the upstream side in the sheet conveying direction of the fixing guide 66 when the fixing opener / closer 64 is in the open position. The opener / closer conveying surface 643 is a surface facing downward when the fixing opener / closer 64 is in the open position.

[0221] The opener / closer conveying surface 643 is an inclined surface that is inclined in a direction closer to the fixing chute 28 as it goes downstream in the sheet conveying direction when the fixing opener / closer 64 is in the open position. When the sheet S conveyed downstream in the sheet conveying direction from the photosensitive drum 54 abuts against the opener / closer conveying surface 643, the sheet S is guided by the opener / closer conveying surface 643 and then taken over by the guide conveying surface 661.

[0222] As Figure 23As shown, in a state where the fixing opening / closing device 64 is in the open position, the end portion 643a on the downstream side in the sheet conveying direction of the opening / closing device conveying surface 643 is located near the fixing slide 28 as compared with the end portion 661a on the upstream side in the sheet conveying direction of the guide member conveying surface 661. That is to say, the distance D1 between the end portion 643a on the downstream side in the sheet conveying direction of the opening / closing device conveying surface 643 and the sheet conveying surface 28A in the fixing slide 28 is smaller than the distance D2 between the end portion 661a on the upstream side in the sheet conveying direction of the guide member conveying surface 661 and the sheet conveying surface 28A in the fixing slide 28.

[0223] Since the distance D1 is smaller than the distance D2, a step is formed between the opening / closing device conveying surface 643 and the guide member conveying surface 661, where the end portion 643a is located nearer to the fixing slide 28 than the end portion 661a. Therefore, the situation where the top end of the sheet S conveyed downstream in the sheet conveying direction from the photosensitive drum 54 and guided by the opening / closing device conveying surface 643 gets stuck on the fixing guide 66 when the sheet S is transferred from the opening / closing device conveying surface 643 to the guide member conveying surface 661 is suppressed, so that the sheet S can be stably conveyed even when the fixing opening / closing device 64 is provided.

[0224] Moreover, in a state where the fixing opening / closing device 64 is in the open position, the end portion 643a on the downstream side in the sheet conveying direction of the opening / closing device conveying surface 643 overlaps with the guide member conveying surface 661 in the sheet conveying direction. That is to say, the end portion 643a on the downstream side in the sheet conveying direction of the opening / closing device conveying surface 643 is located on the downstream side in the sheet conveying direction as compared with the end portion 661a on the upstream side in the sheet conveying direction of the guide member conveying surface 661. Thereby, the sheet S guided by the opening / closing device conveying surface 643 can be smoothly transferred to the guide member conveying surface 661, so that the situation where the sheet S gets stuck on the fixing guide 66 can be suppressed.

[0225] Moreover, the inclination angle θ1 of the opening / closing device conveying surface 643 with respect to the direction along the conveying path P which becomes the sheet conveying direction is formed to be larger than the inclination angle θ2 of the guide member conveying surface 661 with respect to the direction along the conveying path P. Thereby, the space between the opening / closing device conveying surface 643 and the fixing slide 28 can be ensured to be large, and the situation where the conveyed sheet S gets jammed can be suppressed.

[0226] As Figure 22As shown, in a state where the fixing opening / closing device 64 is in the closed position, the opening / closing device conveying surface 643 faces the fixing device 6 and is in a position hidden from view and not visually confirmable from the front. When the processing cartridge 50 is detached from the apparatus main body 2, although the user's hand can be inserted into the apparatus main body 2 from the front, the fixing opening / closing device 64 is in the closed position and the opening / closing device conveying surface 643 faces the fixing device 6 side where it is difficult for the user's hand to contact. Therefore, it is possible to prevent the user's hand from contacting the opening / closing device conveying surface 643 and attaching dirt to the opening / closing device conveying surface 643, and to prevent the sheet S conveyed later from being soiled when it contacts the opening / closing device conveying surface 643.

[0227] [Shielding surface of the fixing opening / closing device]

[0228] Moreover, as Figure 22 shown, the fixing opening / closing device 64 has a shielding surface 644 that covers the upstream side in the sheet conveying direction with respect to the heating unit 61 in a state where the fixing opening / closing device 64 is in the closed position. The shielding surface 644 extends in a direction intersecting the direction in which the opening / closing device conveying surface 643 extends. For example, the angle θ3 formed by the opening / closing device conveying surface 643 and the sheet conveying surface 28A in the fixing chute 28 is smaller than the angle θ4 formed by the shielding surface 644 and the sheet conveying surface 28A in the fixing chute 28, and the angle θ3 is different from the angle θ4.

[0229] In this way, since the fixing opening / closing device 64 has the shielding surface 644, when the fixing opening / closing device 64 is in the closed position, the heating unit 61 is covered by the shielding surface 644, so it is possible to prevent the user from contacting the heating unit 61.

[0230] [Guide projection of the fixing guide]

[0231] Moreover, as Figure 23 、 Figure 24 shown, the fixing guide 66 provided on the upper frame 63A of the fixing frame 63 has guide projections 662 located at the left and right ends in the lateral direction of the guide conveying surface 661. The guide projections 662 project toward the fixing chute 28 side compared to the guide conveying surface 661. The lateral direction is an example of a direction orthogonal to the sheet conveying direction. The guide projections 662 can press the left and right ends of the conveyed sheet S from above.

[0232] The guide projections 662 are inclined in a direction closer to the fixing chute 28 as they go toward the downstream in the sheet conveying direction, and the inclination angle θ5 of the guide projections 662 with respect to the direction along the conveying path P is formed to be greater than the inclination angle θ2 of the guide conveying surface 661 with respect to the direction along the conveying path P.

[0233] When the rear end of the conveyed sheet S passes through the conveying surface 661 of the guide member, sometimes the rear end portion of the sheet S jumps up. However, since the fixing guide member 66 has the guide projection 662, the conveyed sheet S can be pressed by the guide projection 662, suppressing the jumping up generated at the rear end portion of the sheet S.

[0234] In this case, since the inclination angle θ5 of the guide projection 662 is formed to be larger than the inclination angle θ2 of the guide conveying surface 661, even if the guide projection 662 protrudes compared to the guide conveying surface 661, the end portion on the upstream side in the sheet conveying direction of the guide projection 662 can be positioned farther from the fixing slide 28 than the end portion on the downstream side in the sheet conveying direction of the guide conveying surface 661, suppressing the situation where the conveyed sheet S gets stuck on the guide projection.

[0235] [Upstream guide member]

[0236] As Figure 21 、 Figure 23 、 Figure 25 shown, the air duct 26 has an upstream guide member 261. The upstream guide member 261 is located on the opposite side of the fixing slide 28 across the conveying path P in the thickness direction of the sheet S conveyed along the conveying path P.

[0237] The upstream guide member 261 is formed in a rib shape extending in the front-rear direction, and a plurality of upstream guide members 261 are arranged at intervals in the left-right direction. An air vent 262 through which air can flow is formed between the upstream guide members 261 in the left-right direction, and the air in the apparatus main body 2 can flow into the air duct 26 through the air vent 262.

[0238] The upstream guide member 261 can guide the sheet S upstream in the sheet conveying direction from the opening / closing conveying surface 643 of the fixing opening / closing member 64. When the sheet S guided by the upstream guide member 261 is conveyed downstream in the sheet conveying direction from the upstream guide member 261, it transfers from the upstream guide member 261 to the opening / closing conveying surface 643.

[0239] The lower end of the upstream guide member 261 inclines in a direction closer to the fixing slide 28 as it goes downstream in the sheet conveying direction. The end portion 261a on the downstream side in the sheet conveying direction of the upstream guide member 261 is located nearer to the fixing slide 28 than the end portion 643b on the upstream side in the sheet conveying direction of the opening / closing conveying surface 643. That is, the distance D3 between the end portion 261a on the downstream side in the sheet conveying direction of the upstream guide member 261 and the sheet conveying surface 28A in the fixing slide 28 is smaller than the distance D4 between the end portion 643b on the upstream side in the sheet conveying direction of the opening / closing conveying surface 643 and the sheet conveying surface 28A in the fixing slide 28.

[0240] In addition, the "fixing chute" in "near the fixing chute 28" and "in the vicinity of the fixing chute 28" in this description includes a hypothetical plane obtained by extending the sheet conveyance surface 28A in the fixing chute.

[0241] Thus, since the distance D3 is smaller than the distance D4, a step is formed between the upstream guide 261 and the opening / closing device conveyance surface 643 such that the end 261a is closer to the fixing chute 28 than the end 643b. Therefore, when the sheet S guided by the upstream guide 261 is transferred to the opening / closing device conveyance surface 643, the situation where the sheet S gets stuck in the fixing opening / closing device 64 is suppressed, and the sheet S can be stably conveyed.

[0242] [Movable chute]

[0243] As Figures 21 to 23 、 Figure 25 shown, the image forming apparatus 1 has a movable chute 71. The movable chute 71 is located between the process cartridge 50 and the fixing device 6 in the front-rear direction. That is, the movable chute 71 is located downstream of the photosensitive drum 54 and the transfer roller 55 constituting the transfer portion and upstream of the fixing device 6 in the sheet conveyance direction.

[0244] The movable chute 71 is located on the opposite side of the upstream guide 261 across the conveyance path P in the thickness direction of the sheet S conveyed along the conveyance path P, and can guide the conveyed sheet S from below.

[0245] The movable chute 71 can rotate about a rotation shaft 711 located at the front end portion. The movable chute 71 rotates about the rotation shaft 711, so that it can move between a first position ( Figure 21 the position shown by the solid line in Figure 22 ) and a second position ( Figure 21 the position shown by the two-dot chain line in

[0246] ) where the end portion 71a on the downstream side in the sheet conveyance direction is farther from the conveyance path P than the first position.

[0247] In this way, the sheet S is guided by the movable slide 71 at the first position closer to the conveyance path P than the second position. Thus, the sheet conveyed from the transfer unit composed of the photosensitive drum 54 and the transfer roller 55 can be appropriately guided to the fixing unit 6 through the movable slide 71.

[0248] As Figure 21 shown, the movable slide 71 is configured such that in the state of being at the first position, the imaginary plane VS obtained by extending the sheet conveyance surface 71A of the end portion 71a on the downstream side in the sheet conveyance direction of the movable slide 71 passes through the fixing guide 66.

[0249] The tip of the sheet S guided by the sheet conveyance surface 71A of the movable slide 71 may sometimes move to a position downstream of the opener conveyance surface 643 without contacting the opener conveyance surface 643. Such a situation is likely to occur in the case of a curled sheet that curls toward the side separated from the opener conveyance surface 643 or a flat sheet that does not curl particularly.

[0250] In such a case, since the imaginary plane VS of the sheet conveyance surface 71A is configured to pass through the fixing guide 66, the tip of the sheet S guided by the movable slide 71 contacts the guide conveyance surface 661 located at a position downstream of the opener conveyance surface 643, and the sheet S can be more stably guided to the fixing unit 6.

[0251] Moreover, as Figure 21 shown, the perpendicular line VL of the opener conveyance surface 643 in the fixing opener 64 is configured to pass through the sheet conveyance surface 71A of the movable slide 71. In the present embodiment, the perpendicular line VL of the opener conveyance surface 643 is configured to pass through both the sheet conveyance surface 71A of the movable slide 71 at the first position and the sheet conveyance surface 71A of the movable slide 71 at the second position.

[0252] Thereby, the contact angle of the sheet S guided by the movable slide 71 with respect to the opener conveyance surface 643 exceeds 90 degrees, and the situation where the sheet S is guided upstream in the sheet conveyance direction by the opener conveyance surface 643 can be suppressed. Therefore, the sheet S conveyed from the movable slide 71 can be appropriately guided to the fixing unit 6 through the opener conveyance surface 643.

[0253] [Operation of the Movable Slide]

[0254] As Figure 23 shown, the image forming apparatus 1 has a slide spring 72 that applies a force to the movable slide 71. The slide spring 72 applies a force to the movable slide 71 toward the first position side.

[0255] Moreover, as Figure 26As shown, the image forming apparatus 1 has a solenoid 97 as a drive source for moving the movable slide 71. The solenoid 97 is a solenoid actuator for moving the movable slide 71 from the first position to the second position. The solenoid 97 is connected to the control unit 95, and the control unit 95 controls the operation of the solenoid 97.

[0256] After the top end of the conveyed sheet S passes through the fixing device 6, the control unit 95 controls the solenoid 97 to move the movable slide 71 from the first position to the second position. The solenoid 97 is configured to move the movable slide 71 via, for example, a slide link 75.

[0257] In this case, the control unit 95 can, for example, determine that the top end of the sheet S has passed through the fixing device 6 when a predetermined time has elapsed since the alignment post-sensor 98 detects the top end of the sheet S, and control the solenoid 97 to move the movable slide 71 from the first position to the second position.

[0258] Moreover, the control unit 95 can, for example, determine that the rear end of the sheet S has passed through the fixing device 6 when a predetermined time has elapsed since the alignment post-sensor 98 detects the rear end of the sheet S, and control the solenoid 97 to move the movable slide 71 from the second position to the first position.

[0259] [Slide link]

[0260] As Figures 26 to 28 shown, the slide link 75 is connected to the solenoid 97, and the movable slide 71 is pressed by driving the solenoid 97, thereby moving the movable slide 71 from the first position to the second position.

[0261] The solenoid 97 has a main body 921 supported by the second main body frame 25 and a plunger 922 that can move in the left-right direction relative to the main body 921. The plunger 922 is biased to the right from the main body 921 by a biasing member, and in a state where the solenoid 97 is not driven by the control unit 95, it is in a state where the plunger 922 moves to the right and enters from the main body 921. On the other hand, in a state where the solenoid 97 is driven by the control unit 95, it is in a state where the plunger 922 is pulled into the main body 921 and moves to the left.

[0262] The slide link 75 has a first link 751, a second link 752, and a third link 753. The first link 751 and the second link 752 are located inside the air duct 26, and the third link 753 protrudes downward from the inside of the air duct 26. A cage 77 for supporting the slide link 75 is installed inside the air duct 26.

[0263] The first link 751 is a long-sized member extending in the left-right direction and is supported by the cage 77 so as to be movable in the left-right direction. The first link 751 has a first end 751a as the left end and a second end 751b as the right end. The first end 751a is connected to the plunger 922 of the solenoid 97. The second end 751b abuts against the second link 752.

[0264] The second link 752 is a long-sized member extending in the left-right direction and is located below the first link 751. The second link 752 has a rotation shaft portion 752a at the right end, an abutting portion 752b extending upward from the rotation shaft portion 752a, a tip portion 752c as the left end, and an engaging portion 752d extending obliquely upward and to the right from the rotation shaft portion 752a. The second link 752 is supported by the cage 77 so as to be rotatable about the rotation shaft portion 752a.

[0265] The image forming apparatus 1 has a link spring 76 that applies a force to the second link 752. The link spring 76 is attached to the cage 77. One end of the link spring 76 is engaged with the hook 771 of the cage 77, and the other end of the link spring 76 is engaged with the engaging portion 752d of the second link 752. The second link 752 is urged by the link spring 76 and thus rotates in the direction of moving upward toward the tip portion 752c. The abutting portion 752b abuts against the second end 751b of the first link 751, and when the first link 751 moves to the left, the abutting portion 752b is pressed to the left by the second end 751b, and the second link 752 rotates in the direction of moving downward toward the tip portion 752c.

[0266] The third link 753 is a long-sized member extending in the up-down direction and is configured to be movable in the up-down direction. The third link 753 has a connection portion 753a at the upper end and a pressing portion 753b at the lower end. The connection portion 753a is connected to the tip portion 752c of the second link 752, and the pressing portion 753b can press the pressed portion 71B of the movable slide 71.

[0267] The pressed portion 71B of the movable slide 71 is formed on the sheet conveyance surface 71A side and faces upward. The sheet conveyance surface 71A of the movable slide 71 is formed in the region through which the sheet S passes in the left-right direction, and the pressed portion 71B is located outside the left-right direction compared to the region where the sheet conveyance surface 71A is formed. In the present embodiment, the pressed portion 71B is located on the left side of the region where the sheet conveyance surface 71A is formed.

[0268] The pressing portion 753b of the third link 753 and the pressed portion 71B of the movable slide 71 are opposed to each other in the up-down direction, and by moving the third link 753 downward, the pressing portion 753b presses the pressed portion 71B.

[0269] In the slide link 75 configured in this way, in the disconnected state where the solenoid 97 is not driven by the control unit 95, the first link 751 connected to the plunger 922 is in a state of moving to the right, and the second link 752 rotates in the direction of moving upward toward the tip 752c by the action of the link spring 76.

[0270] The third link 753 is in a state of moving upward by the second link 752, and the pressing portion 753b of the third link 753 is separated from the pressed portion 71B of the movable slide 71. The movable slide 71 moves to the first position by the action of the slide spring 72.

[0271] On the other hand, in the conductive state where the solenoid 97 is driven by the control unit 95, the first link 751 moves to the left by the plunger 922 attracted by the main body 921. When the first link 751 moves to the left, the abutting portion 752b of the second link 752 is pressed by the second end portion 751b of the first link 751, and the second link 752 rotates in the direction of moving downward toward the tip 752c against the action of the link spring 76.

[0272] The third link 753 moves downward following the rotation of the second link 752, and presses the pressed portion 71B of the movable slide 71 downward by the pressing portion 753b of the third link 753, so that the movable slide 71 moves from the first position to the second position against the action of the slide spring 72.

[0273] In this way, the slide link 75 is configured to press the movable slide 71 from the sheet conveyance surface 71A side by driving the solenoid 97, thereby moving the movable slide 71 from the first position to the second position. Thus, the movable slide 71 can be quickly and stably moved from the first position to the second position.

[0274] Moreover, with such a configuration, after the tip of the conveyed sheet S passes through the fixing unit 6, the control unit 95 can turn on the solenoid 97 and press the movable slide 71 from the sheet conveyance surface 71A side by the slide link 75, thereby moving the movable slide 71 from the first position to the second position.

[0275] Furthermore, after the rear end of the conveyed sheet S passes through the transfer portion composed of the photosensitive drum 54 and the transfer roller 55, the control unit 95 can turn off the solenoid 97, separate the slide link 75 from the movable slide 71, and move the movable slide 71 from the second position to the first position by the action of the slide spring 72.

[0276] In the image forming apparatus 1, there is a period during which the sheet S is conveyed by both the fixing unit 6 and the transfer portion composed of the photosensitive drum 54 and the transfer roller 55 after the tip of the sheet S passes through the fixing unit 6.

[0277] During this period, the conveyance speed at which the photosensitive drum 54 and the transfer roller 55 constituting the transfer unit convey the sheet S is greater than the conveyance speed at which the fixing device 6 conveys the sheet S, and thus the sheet S between the fixing device 6 and the transfer unit is deflected. Therefore, the movable slide 71 is moved to the second position separated from the conveyance path P by the control of the control unit 95, whereby the space between the fixing device 6 and the transfer unit can be ensured to be large, and the interference of the deflected sheet S with other parts of the apparatus main body 2 can be suppressed.

[0278] Moreover, after the rear end of the sheet S passes through the transfer unit constituted by the photosensitive drum 54 and the transfer roller 55, there is no sheet S conveyed by both the fixing device 6 and the transfer unit. Therefore, by the control of the control unit 95, the solenoid 97 is turned off and the movable slide 71 is moved to the first position, thereby enabling power saving of the image forming apparatus 1. Moreover, the sheet S subsequently conveyed from the transfer unit can be appropriately guided by the movable slide 71 located at the first position.

Claims

1. An image forming device, characterized in that: have: Device body; a fuser having a heating portion for fixing the toner image on the conveyed sheet; a fixing slide, which is located upstream of the fixing device in the sheet conveying direction and forms a sheet conveying path; a fixing guide, located upstream of the heating portion in the sheet conveying direction, the fixing guide being located on the opposite side of the fixing slideway across the sheet conveying path in the sheet thickness direction, guiding the sheet, and the fixing guide having a guide conveying surface, the guide conveying surface being inclined in a direction closer to the fixing slideway as it moves downstream in the sheet conveying direction; as well as a fixing shutter, the fixing shutter being located on the opposite side of the fixing slideway across the sheet conveying path in the sheet thickness direction and being movable to a closed position covering the upstream side of the heating section in the sheet conveying direction and an open position opening the upstream side of the heating section in the sheet conveying direction, The fixing shutter has a shutter conveying surface, and when the fixing shutter is located in the open position, the shutter conveying surface can guide the sheet on the upstream side of the fixing guide in the sheet conveying direction, and when the fixing shutter is located in the open position, the shutter conveying surface is inclined in a direction closer to the fixing slide as it moves toward the downstream in the sheet conveying direction, so that the end of the shutter conveying surface on the downstream side in the sheet conveying direction is located closer to the fixing slide than the end of the guide conveying surface on the upstream side in the sheet conveying direction.

2. The image forming apparatus according to claim 1, wherein: When the fixing shutter is located at the open position, an end portion of the shutter conveying surface on the downstream side in the sheet conveying direction overlaps with the guide conveying surface in the sheet conveying direction.

3. The image forming apparatus according to claim 1 or 2, wherein: The inclination angle of the shutter conveying surface with respect to the sheet conveying direction is greater than the inclination angle of the guide conveying surface with respect to the sheet conveying direction.

4. The image forming apparatus according to claim 1 or 2, wherein: In a state where the fixing shutter is located at the closed position, the shutter conveying surface of the fixing shutter faces the fixing device.

5. The image forming apparatus according to claim 1 or 2, wherein: The fixing shutter has a shielding surface that covers the upstream side of the heating portion in the sheet conveying direction when the fixing shutter is in the closed position and extends in a direction intersecting the direction in which the shutter conveying surface extends.

6. The image forming apparatus according to claim 5, wherein: have: a box that can be attached to and detached from the device body; and A shutter link is provided in the device body and is connected to the fixing shutter. The shutter link moves the fixing shutter to the open position and the closed position in conjunction with the attachment and detachment of the cartridge relative to the device body.

7. The image forming apparatus according to claim 6, wherein: An upstream guide member is provided, the upstream guide member being capable of guiding the sheet upstream of the shutter conveying surface of the fixing shutter in the sheet conveying direction, An end portion of the upstream guide on the downstream side in the sheet conveying direction is located closer to the fixing chute than an end portion of the shutter conveying surface on the upstream side in the sheet conveying direction.

8. The image forming apparatus according to claim 1 or 2, wherein: A movable slide is provided, which is located downstream of a transfer section that transfers an image to a sheet and upstream of the fixer in the sheet conveying direction, and is capable of moving between a first position and a second position, wherein the second position is a position where the end of the movable slide on the downstream side of the sheet conveying direction is farther away from the sheet conveying path than the first position.

9. The image forming apparatus according to claim 8, wherein: The movable slide has a sheet conveying surface for guiding the sheet. When the movable chute is located at the first position, a virtual plane obtained by extending a sheet conveying surface at an end portion on the downstream side in the sheet conveying direction of the movable chute passes through the fixing guide.

10. The image forming apparatus according to claim 8, wherein: A perpendicular line of the shutter conveying surface in the fixing shutter passes through the movable slide.

11. The image forming apparatus according to claim 8, wherein: have: a driving source for moving the movable slide; and a control unit that controls the operation of the driving source, After the leading end of the conveyed sheet passes through the fixing device, the control unit controls the driving source to move the movable slide from the first position to the second position.

12. The image forming apparatus according to claim 11, wherein: A slide link is provided, the slide link is connected to the driving source, and moves the movable slide from the first position to the second position, The driving source is a solenoid actuator that drives the slide link, The movable slide has a sheet conveying surface for guiding the sheet. The chute link is driven by the driving source to press the movable chute from the sheet conveying surface side, thereby moving the movable chute from the first position to the second position.

13. The image forming apparatus according to claim 1 or 2, wherein: The fixing guide has a guide protrusion which is located at an end of the guide conveying surface in a direction perpendicular to the sheet conveying direction and protrudes toward the fixing chute side relative to the guide conveying surface. The guide protrusion is inclined in a direction closer to the fixing slideway as it moves downstream in the sheet conveying direction. The guide protrusion has an inclination angle relative to the sheet conveying direction that is greater than an inclination angle of the shutter conveying surface relative to the sheet conveying direction.

Images