Image forming apparatus

Abstract

To expand a space through which a user puts their hand during jam processing.SOLUTION: An image forming apparatus comprises: a transfer roller 53 that forms a transfer nip NP1 with a toner image carrier (photoconductor drum 51); a fixing device 6; a movable chute SH that guides a sheet S between the transfer roller 53 and the fixing device 6; a moving device TM that moves the movable chute SH; and a control unit. The fixing device 6 has a heating rotating body 61, and a pressure rotating body that forms a fixing nip NP2 with the heating rotating body 61. The movable chute SH is movable between a first position and a second position. When seen from an axial direction of the transfer roller 53, the second position is farther away than the first position from a straight line LN connecting a downstream end of the transfer nip NP1 and an upstream end of the fixing nip NP2. The control unit controls the moving device TM to move the movable chute SH only between the first position and the second position. The movable chute SH is movable to a third position farther away from the straight line LN than the second position.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus.

Background Art

[0002] Conventionally, as an image forming apparatus, one including a fixing device, a guide, a solenoid, and a control unit is known (see Patent Document 1). The guide is a guide that guides a sheet toward the fixing device. The guide is rotatable between a first position and a second position below the first position.

[0003] During printing control, the control unit turns on the solenoid before the sheet enters the fixing device to position the guide at the first position. When the vicinity of the center of the sheet passes the tip of the guide, the control unit turns off the solenoid to position the guide at the second position.

[0004] The rotation range of the guide is determined by two fixing plates. The guide is positioned at the first position by contacting the upper fixing plate. The guide is positioned at the second position by contacting the lower fixing plate.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the conventional technology, since the guide can only rotate within the range from the first position to the second position, when the sheet gets jammed near the guide, the space for the user to put their hand in is narrow, and the operation of taking out the sheet (hereinafter, also referred to as "jam processing") may become complicated.

[0007] Therefore, an object of the present disclosure is to provide an image forming apparatus capable of expanding the space for a user to insert their hand during jam processing.

Means for Solving the Problems

[0008] The image forming apparatus includes a toner image carrier, a transfer roller, a fixing device, a movable chute, a moving device, and a control unit. The toner image carrier carries a toner image. The transfer roller transfers the toner image on the toner image carrier to a sheet. The transfer roller forms a transfer nip with the toner image carrier. The fixing device fixes the toner image transferred to the sheet to the sheet. The fixing device has a heating rotator and a pressure rotator. The heating rotator heats the sheet. The pressure rotator presses the sheet. The pressure rotator forms a fixing nip with the heating rotator. The movable chute is disposed downstream of the transfer roller and upstream of the fixing device in the conveyance direction of the sheet. The movable chute guides the sheet. The movable chute is movable between a first position and a second position. The second position is farther from the first position with respect to a straight line connecting the downstream end of the transfer nip and the upstream end of the fixing nip as viewed in the axial direction of the transfer roller. The moving device is a device for moving the movable chute. The control unit moves the movable chute only between the first position and the second position by controlling the moving device. The movable chute is movable to a third position farther from the straight line than the second position.

[0009] Since the movable chute can move to a third position farther from the straight line than the second position, the movable chute can move in a range larger than the range in which it is moved by the control unit, so that the space for a user to insert their hand during jam processing can be expanded.

[0010] Further, the movable chute may be movable in a direction from the first position to the third position while the moving device is stopped.

[0011] Since the movable chute can be moved in a direction from the first position to the third position while the moving device is stopped, the moving device does not become a resistance when moving the movable chute to the third position, so the movable chute can be moved smoothly.

[0012] Further, the image forming apparatus may further include a spring that biases the movable chute toward the first position.

[0013] By configuring the spring to bias the movable chute toward the first position, when the user strongly pushes the movable chute from the first position to the third position, the spring can suppress the moving speed of the movable chute from becoming too large.

[0014] Further, when it is determined that the sheet is jammed during sheet conveyance, the control unit may control the moving device to position the movable chute at the first position.

[0015] When the sheet is jammed during sheet conveyance, by configuring the movable chute to be positioned at the first position, when the sheet is located between the transfer nip and the fixing nip, the sheet that contacts the movable chute is located near a straight line, so it is easy for the user to grasp the sheet.

[0016] Further, the moving device may have a solenoid actuator. In this case, the control unit moves the movable chute between the first position and the second position by controlling the solenoid actuator.

[0017] Further, the movable chute may have a guide surface for guiding the sheet. In this case, the moving device may have a pressing surface that presses the movable chute from the guide surface side.

[0018] By configuring the moving device to press the movable chute from the guide surface side, there is no need to arrange the moving device in the space on the third position side with respect to the movable chute located at the first position, so that the movable chute can be moved smoothly.

[0019] Further, the image forming apparatus may further include a link mechanism that moves by the driving force of the solenoid actuator. In this case, the link mechanism has a first link, a second link, and a third link. One end of the first link is connected to the solenoid actuator. The first link is movable in the axial direction. The second link is connected to the other end of the first link. The second link is rotatable about the first axis by the movement of the first link. The third link has a pressing surface. The third link is connected to the second link. The third link pushes the movable chute toward the second position as the second link rotates.

[0020] By configuring the link mechanism to push the movable chute, the amount of movement of the movable chute from the first position to the second position can be increased.

[0021] Further, the movable chute may be rotatable about the second axis and may extend downstream in the conveyance direction from the second axis. The second position may be a position lower than the first position. In this case, when the movable chute is located at the first position, the tip of the movable chute may be located above the transfer nip. Also, when the movable chute is located at the second position, the tip of the movable chute may be located below the transfer nip.

[0022] By configuring the tip of the movable chute located at the first position to be positioned above the transfer nip, when the sheet gets jammed while being located between the transfer nip and the fixing nip, the tip of the movable chute located at the first position supports the sheet, making it easier for the user to grasp the rear end of the sheet. Also, when the sheet is supported by the tip of the movable chute located at the first position, a space is likely to be formed between the movable chute and the sheet, making it easier for the user to insert a finger into the space and grasp the sheet.

[0023] Further, the downstream end of the movable chute in the conveyance direction of the sheet may be farther from a straight line when the movable chute is in the second position than when it is in the first position, and may be farther from a straight line when the movable chute is in the third position than when it is in the second position.

[0024] Also, the image forming apparatus of the present disclosure may have the following configuration. The image forming apparatus includes a transfer roller, a fixing device, a movable chute, a moving device, and a control unit. The transfer roller transfers the toner image onto the sheet. The fixing device fixes the toner image transferred onto the sheet to the sheet. The movable chute is disposed downstream of the transfer roller and upstream of the fixing device in the conveyance direction of the sheet. The movable chute guides the sheet. The movable chute is movable in order to the first position, the second position, and the third position in a direction intersecting the surface of the sheet. The moving device is a device for moving the movable chute. The control unit moves the movable chute only between the first position and the second position by controlling the moving device.

[0025] Since the movable chute can move from the second position to the third position, it can move in a range larger than the range in which the movable chute is moved by the control unit, so that the space for the user to insert their hand during jam processing can be expanded.

[0026] Further, the fixing device may include a fixing housing and a fixing shutter. In this case, the fixing housing has an opening through which the sheet conveyed toward the inside of the fixing device passes. The fixing shutter is movable between an open position where the opening is opened and a closed position where the opening is covered.

[0027] By configuring the fixing device to include the fixing shutter, when a jam occurs while the sheet is positioned between the transfer nip and the fixing nip, the fixing shutter can prevent the user's hand from entering the fixing housing.

[0028] Furthermore, the image forming apparatus may further include a main body housing and a cartridge detachably attached to the main body housing. In this case, the fixing shutter may move from the closed position to the open position during the process of attaching the cartridge to the main body housing. Also, the fixing shutter may move from the open position to the closed position during the process of removing the cartridge from the main body housing.

[0029] By configuring the fixing shutter to open and close in conjunction with the attachment and detachment of the cartridge, when a jam occurs while the sheet is positioned between the transfer nip and the fixing nip, if the user removes the cartridge from the main body housing, the fixing shutter closes, more reliably preventing the user's hand from entering the fixing housing.

Advantages of the Invention

[0030] During jam processing, the space for the user to insert their hand can be expanded.

Brief Description of the Drawings

[0031]

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Embodiments for Carrying Out the Invention

[0032] Next, the embodiments will be described in detail with appropriate reference to the drawings. As shown in FIG. 1, the image forming apparatus 1 is a laser printer and forms an image on a sheet S. The image forming apparatus 1 includes a main body housing 2, a supply unit 3, a process unit 4, a fixing device 6, and a discharge unit 7. In the following description, the axial direction of the transfer roller 53 described later is also referred to as the "first direction". Also, the conveyance direction of the sheet S from the process unit 4 toward the fixing device 6 is also referred to as the "second direction". The vertical direction is also referred to as the "third direction".

[0033] The first direction intersects the second direction. The third direction intersects the first direction and the second direction. In this embodiment, the first direction is orthogonal to the second direction. The third direction is orthogonal to the first direction and the second direction. Also, the arrows indicating the respective directions in the drawings point to the "one side" in each direction.

[0034] The supply unit 3 includes a supply tray 31 and a sheet supply device 32. The supply tray 31 is a tray for accommodating the sheet S. The sheet supply device 32 conveys the sheet S in the supply tray 31 toward the process unit 4.

[0035] The process unit 4 forms a toner image on the supplied sheet S. The process unit 4 includes an exposure device 40 and a process cartridge 50 as an example of a cartridge.

[0036] The exposure device 40 is provided at the upper part inside the main body housing 2 and includes a laser light emitting part (not shown), a polygon mirror 41 that rotates, a lens 42, and a reflecting mirror 44. The laser light (refer to the dashed line) based on the image data emitted from the laser light emitting part is reflected or passes through the polygon mirror 41, the lens 42, and the reflecting mirror 44 in this order and is scanned at high speed on the surface of the photosensitive drum 51.

[0037] The process cartridge 50 is disposed below the exposure device 40. The process cartridge 50 is configured to be detachable from the main body housing 2 through an opening formed when the front cover 23 provided on the main body housing 2 is opened. The process cartridge 50 includes a photosensitive drum 51 as an example of a toner image carrier, a charger 52, a transfer roller 53, a developing roller 54, a supply roller 55, a toner storage part 56, and a toner memory 57.

[0038] The photosensitive drum 51 rotates about a rotation axis X1 extending in the first direction. The photosensitive drum 51 carries the toner image.

[0039] The transfer roller 53 rotates about a rotation axis X4 extending in the first direction. The transfer roller 53 transfers the toner image on the photosensitive drum 51 to the sheet S. The transfer roller 53 forms a transfer nip NP1 between the transfer roller 53 and the photosensitive drum 51. Here, the transfer nip NP1 refers to the portion where the transfer roller 53 contacts the photosensitive drum 51. The toner memory 57 is a memory in which the information of the process cartridge 50 is stored.

[0040] The fixing device 6 fixes the toner image transferred onto the sheet S onto the sheet S. The fixing device 6 is provided on the downstream side of the process unit 4 in the conveyance direction of the sheet S. In the following description, the "conveyance direction of the sheet S" is also simply referred to as the "conveyance direction". The fixing device 6 includes a heating rotator 61, a pressure rotator 62, and a fixing housing 63.

[0041] The heating rotator 61 is a member that heats the sheet S. The heating rotator 61 is an endless belt. The heating rotator 61 houses a heater inside and rotates while sandwiching the sheet S between itself and the pressure rotator 62 to heat the sheet S.

[0042] The pressure rotator 62 is a member that pressurizes the sheet S. The pressure rotator 62 forms a fixing nip NP2 between itself and the heating rotator 61. Here, the fixing nip NP2 refers to the portion where the heating rotator 61 contacts the pressure rotator 62. The pressure rotator 62 is a roller whose surface is made of a non-conductive elastic body. The heating rotator 61 and the pressure rotator 62 are pressed against each other by a pressing member (not shown).

[0043] The fixing housing 63 is a frame that covers the heating rotator 61 and the pressure rotator 62. The fixing housing 63 rotatably supports the heating rotator 61 and the pressure rotator 62.

[0044] In the process unit 4, after the surface of the photosensitive drum 51 is charged by the charger 52, it is exposed by the laser light from the exposure device 40, and thus an electrostatic latent image is formed on the photosensitive drum 51. Also, the toner in the toner container 56 is supplied to the developing roller 54 via the supply roller 55 and is carried on the developing roller 54.

[0045] Then, the toner carried on the developing roller 54 is supplied to the electrostatic latent image on the photosensitive drum 51, thereby visualizing the electrostatic latent image and forming a toner image on the photosensitive drum 51. Thereafter, the sheet S supplied from the supply unit 3 is conveyed between the photosensitive drum 51 and the transfer roller 53 (transfer nip NP1), and a transfer bias is applied to the transfer roller 53, whereby the toner image on the photosensitive drum 51 is transferred onto the sheet S. Next, the sheet S is conveyed between the heating rotator 61 and the pressure rotator 62 (fixing nip NP2), whereby the toner image transferred onto the sheet S is thermally fixed.

[0046] The discharging unit 7 conveys the sheet S on which the toner image has been thermally fixed toward the outside of the main body housing 2. The discharging unit 7 has a discharging roller 73. The discharging roller 73 discharges the sheet S to the discharge tray 22.

[0047] The image forming apparatus 1 has a re-conveying mechanism 9. The re-conveying mechanism 9 is a mechanism that re-conveys the sheet S to the process unit 4 in a state where the front and back of the sheet S are reversed in order to form an image on the second surface on the back side of the sheet S after the image is formed on the first surface of the sheet S. In FIG. 1, the re-conveyed sheet S is indicated by a two-dot chain line.

[0048] The re-conveying mechanism 9 includes a flapper 91 and a plurality of re-conveying rollers 92, 93, 94. The flapper 91 is rotatable between an initial position indicated by a solid line and a re-conveying position indicated by a two-dot chain line. When the flapper 91 is in the initial position, the sheet S discharged from the fixing device 6 is guided toward the discharge tray 22. When the flapper 91 is in the re-conveying position, the sheet S discharged from the fixing device 6 is guided toward the re-conveying path by the reverse rotation of the discharging roller 73 at a predetermined timing.

[0049] Furthermore, the image forming apparatus 1 includes a guide member 100. The guide member 100 is located below the process cartridge 50 and guides the sheet S from the transfer nip NP1 toward the fixing nip NP2. Also, the guide member 100 guides the sheet S in the re-feed path toward the transfer nip NP1. The re-feed path is formed below the guide member 100. As shown in FIG. 2, the guide member 100 includes a base portion 110, a movable chute SH, and a spring 130.

[0050] The base portion 110 has a first recess 111, a second recess 112, and a lower surface 113. The first recess 111 is located at an end on the other side in the second direction on the upper surface of the base portion 110. The first recess 111 is a portion into which a part of the transfer roller 53 enters. The second recess 112 is located at an end on one side in the second direction on the upper surface of the base portion 110. The second recess 112 is a portion that rotatably supports the movable chute SH. The lower surface 113 is the lower surface of the base portion 110 and is a guide surface for guiding the sheet S in the re-feed path.

[0051] The movable chute SH is located between the photosensitive drum 51 and the fixing device 6 in the conveyance direction of the sheet S. In other words, the movable chute SH is disposed downstream of the transfer roller 53 and upstream of the fixing device 6 in the conveyance direction of the sheet S. The movable chute SH guides the sheet S. The movable chute SH is movable to a first position shown in FIG. 2, a second position shown in FIG. 3, and a third position shown in FIG. 4. The movable chute SH is rotatable within a range from the first position to the third position.

[0052] The movable chute SH is movable in order to the first position, the second position, and the third position in a direction intersecting the surface of the sheet S. The second position is farther from the first position with respect to a straight line LN (see FIG. 3) connecting the downstream end of the transfer nip NP1 and the upstream end of the fixing nip NP2 as viewed from the axial direction of the transfer roller 53. Here, since the straight line LN connecting the downstream end of the transfer nip NP1 and the upstream end of the fixing nip NP2 overlaps the sheet S shown by a broken line in FIG. 2, the illustration is omitted. The third position is farther from the straight line LN than the second position.

[0053] In this embodiment, the second position is located below the first position. The third position is located below the second position. The movable chute SH is rotatable between the first position and the third position about the rotation axis X2 as an example of the second axis.

[0054] The movable chute SH extends downstream in the conveyance direction from the rotation axis X2. When the movable chute SH is in the first position, the tip of the movable chute SH, that is, the downstream end in the conveyance direction, is located above the transfer nip NP1. Also, when the movable chute SH is in the second position or the third position, the tip of the movable chute SH is located below the transfer nip NP1.

[0055] Also, the downstream end of the movable chute SH in the conveyance direction is farther from the straight line LN when the movable chute SH is in the second position than when it is in the first position. The downstream end of the movable chute SH in the conveyance direction is farther from the straight line LN when the movable chute SH is in the third position than when it is in the second position.

[0056] As shown in FIG. 5, the movable chute SH includes a chute body 120, a chute sheet metal 410, and a mounting member 420 shown in FIG. 21. The mounting member 420 is a member for attaching the chute sheet metal 410 to the chute body 120. Note that the structure and method for attaching the chute sheet metal 410 to the chute body 120 will be described in detail later.

[0057] The chute body 120 includes a base portion 121, a plurality of guide ribs 122, a cylindrical portion 123, a pressed portion 124, and a stopper 125.

[0058] The base portion 121 has a plate shape that is curved so as to be concave downward when viewed from the first direction. The base portion 121 extends in the first direction and the second direction.

[0059] The plurality of guide ribs 122 are ribs protruding upward from the base portion 121 and extending in the second direction along the curvature of the base portion 121. The upper surfaces of the plurality of guide ribs 122 serve as guide surfaces 122A for guiding the sheet S.

[0060] The cylindrical portion 123 is disposed at the other end of the base portion 121 in the second direction. The cylindrical portions 123 are respectively disposed at both ends of the movable chute SH in the first direction. The cylindrical portion 123 is formed in a cylindrical shape centered on the rotation axis X2. The cylindrical portion 123 is rotatably supported by the base portion 110.

[0061] The pressed portion 124 is disposed at one end of the movable chute SH in the first direction and at one end in the second direction. The pressed portion 124 protrudes upward from the base portion 121. The pressed portion 124 is a portion that is pressed by the link mechanism 200 described later when the movable chute SH moves from the first position to the second position.

[0062] The stopper 125 contacts the duct DU described later to restrict the upward movement of the movable chute SH. The stopper 125 is located between the cylindrical portion 123 and the pressed portion 124 in the second direction. The stoppers 125 are disposed at both ends of the movable chute SH in the first direction.

[0063] The spring 130 is a torsion spring. The spring 130 is disposed at both ends of the movable chute SH in the first direction, respectively. The spring 130 has a coil portion 131, a first arm 132, and a second arm 133. The coil portion 131 is engaged with the outside of the cylindrical portion 123. The first arm 132 extends from the coil portion 131 and is hooked on the base portion 110. The second arm 133 extends from the coil portion 131 and is hooked on the movable chute SH. The spring 130 always biases the movable chute SH upward. That is, the spring 130 biases the movable chute SH toward the first position. Thereby, when the movable chute SH is not pressed by the link mechanism 200, the movable chute SH is pushed upward by the spring 130, the stopper 125 contacts the duct DU, and the movable chute SH is positioned at the first position.

[0064] As shown in FIG. 2, the image forming apparatus 1 further includes an exhaust fan FA, a duct DU, and a moving device TM. The exhaust fan FA can discharge the air inside the main body housing 2 to the outside of the main body housing 2.

[0065] The duct DU is a member that guides the air inside the main body housing 2 to the exhaust fan FA in order to discharge the air inside the main body housing 2 to the outside of the main body housing 2. Specifically, the air inside the main body housing 2 is guided from one side to the other side in the first direction (see FIG. 7). The duct DU extends in the first direction. The duct DU overlaps the movable chute SH when viewed from the vertical direction.

[0066] The moving device TM is a device for moving the movable chute SH. As shown in FIG. 7, the moving device TM includes a solenoid actuator 150 and a link mechanism 200. The solenoid actuator 150 is disposed at one end of the duct DU in the first direction. The exhaust fan FA is disposed at the other end of the duct DU in the first direction. That is, the duct DU is positioned between the exhaust fan FA and the solenoid actuator 150.

[0067] As shown in FIG. 6, the solenoid actuator 150 includes a main body portion 151 and a movable portion 152. The image forming apparatus 1 further includes a control unit CU.

[0068] The main body portion 151 has a rectangular parallelepiped shape. The movable portion 152 is a pin that is movable with respect to the main body portion 151 and is slidable in the first direction. The movable portion 152 is movable between a forward position shown in FIG. 7 and a retracted position shown in FIG. 8. The movable portion 152 is located at the forward position when no ON signal is sent from the control unit CU. When an ON signal is sent from the control unit CU, the movable portion 152 is pulled by an electromagnetic force and moves from the forward position to a retracted position on one side in the first direction. When the ON signal from the control unit CU stops being sent, the movable portion 152 returns to the forward position by the biasing force of a coil spring 250 described later. When the movable portion 152 is located at the forward position, the movable chute SH is located at the first position. Also, when the movable portion 152 is located at the retracted position, the movable chute SH is located at the second position.

[0069] The link mechanism 200 is a mechanism that moves by the driving force of the solenoid actuator 150. The link mechanism 200 includes a first link 210, a second link 220, a third link 230, a holder 240, and a coil spring 250.

[0070] The holder 240 holds a part of the link mechanism 200. The holder 240 is supported by the duct DU while holding the link mechanism 200. The holder 240 includes a base portion 241, an extending portion 242, a first hook 243, a boss 244, and a contact portion 245.

[0071] The base portion 241 extends in the first direction. The extending portion 242 extends upward and to one side in the first direction from one end of the base portion 241 on one side in the first direction. The extending portion 242 covers a part of the upper side of the main body portion 151 of the solenoid actuator 150. As shown in FIG. 7, the extending portion 242 has an engaging claw 242A protruding downward from the extending portion 242. The engaging claw 242A is engaged with the upper surface of the main body portion 151 of the solenoid actuator 150. Thereby, the holder 240 is positioned in the first direction with respect to the solenoid actuator 150.

[0072] The first hook 243 is located at the other end of the base portion 241 in the first direction. One end of the coil spring 250 is engaged with the first hook 243.

[0073] The boss 244 is arranged at the other end of the base portion 241 in the first direction. The boss 244 is a cylindrical protrusion protruding from the base portion 241 to one side in the second direction. The boss 244 rotatably supports the second link 220.

[0074] The abutting portion 245 is arranged between the extending portion 242 and the boss 244 in the first direction. The abutting portion 245 is a protrusion protruding from the base portion 241 to one side in the second direction. The abutting portion 245 has a first abutting surface 241A and a second abutting surface 241B. Sponges are respectively attached to the surfaces of the first abutting surface 241A and the second abutting surface 241B. Each sponge is configured to be crushed to a predetermined thickness when pressed by the first link 210 or the second link 220.

[0075] The first abutting surface 241A faces the other side in the first direction. The first abutting surface 241A abuts against the first link 210 through the sponge when the movable portion 152 moves from the forward position to the retracted position.

[0076] The second abutting surface 241B faces downward. The second abutting surface 241B is a surface that abuts against the second link 220 through the sponge when the movable portion 152 moves from the retracted position to the forward position.

[0077] The first link 210 is connected to the movable part 152 of the solenoid actuator 150, and is a member that slides in the first direction together with the movable part 152 when the movable part 152 moves in the first direction. The first link 210 extends in the first direction. The first link 210 has a base part 211, a first hole 213, and a first protrusion 214.

[0078] The base part 211 has a rectangular bar shape extending in the first direction. One end of the base part 211 in the first direction is connected to the tip of the movable part 152 of the solenoid actuator 150. Thus, when the movable part 152 moves in the first direction, the first link 210 also moves in the first direction along with the movement.

[0079] The first hole 213 is arranged at the other end of the base part 211 in the first direction. The first hole 213 is a rectangular hole penetrating in the vertical direction.

[0080] The first protrusion 214 extends downward from one end of the base part 211 in the first direction. The first protrusion 214 is located on one side in the first direction rather than at the center of the base part 211 in the first direction. The first protrusion 214 is a part that comes into contact with the first contact surface 241A of the holder 240 via a sponge when the movable part 152 moves from the forward position to the retracted position.

[0081] The second link 220 is connected to the first link 210, and is a member that rotates about the first axis X3 when the first link 210 moves in the first direction. The second link 220 is located below the first link 210. The second link 220 has a base part 221, a cylindrical part 222, a second protrusion 223, a third protrusion 224, a second hook 225, and a third contact surface 226.

[0082] The base portion 221 has a rectangular bar shape extending in the first direction. The cylindrical portion 222 is disposed at the other end of the base portion 221 in the first direction. The cylindrical portion 222 is formed in a cylindrical shape. Inside the cylindrical portion 222, the boss 244 of the holder 240 fits in. When the boss 244 fits into the cylindrical portion 222, the second link 220 becomes rotatable about the first axis X3.

[0083] The second protrusion 223 protrudes upward from the outer peripheral surface of the cylindrical portion 222. The second protrusion 223 fits into the first hole 213 of the first link 210. Thereby, the second link 220 is connected to the other end of the first link 210, and due to the movement of the first link 210, it becomes rotatable about the first axis X3. Specifically, when the first link 210 moves to one side in the first direction, since the first link 210 presses the second protrusion 223 to one side in the first direction, the second link 220 rotates clockwise in FIG. 6.

[0084] The third protrusion 224 protrudes to one side in the first direction from one end of the base portion 221 in the first direction. The third protrusion 224 is connected to the third link 230.

[0085] The second hook 225 protrudes upward from the outer peripheral surface of the cylindrical portion 222. The second hook 225 is located on the other side in the first direction than the second protrusion 223. The other end of the coil spring 250 engages with the second hook 225.

[0086] The third contact surface 226 is a surface located above one end portion of the base portion 221 in the first direction. When the second link 220 rotates counterclockwise and rises in FIG. 6, the third contact surface 226 contacts the second contact surface 241B via a sponge. When the third contact surface 226 contacts the second contact surface 241B, the second link 220 does not rotate any further.

[0087] The third link 230 is connected to the second link 220 and is a member that slides vertically in response to the vertical movement of the third protrusion 224 of the second link 220 when the second link 220 rotates. Specifically, the third link 230 is movable between a pressing position and a permitting position when the second link 220 rotates. The pressing position is the position where the third link 230 pushes down the movable chute SH to the second position. The permitting position is the position where the third link 230 does not push down the movable chute SH and permits the movable chute SH to be located at the first position. The third link 230 extends in the vertical direction and is located below the second link 220. The third link 230 has a base portion 231, a third hole 232, and a chute pressing portion 233.

[0088] The base portion 231 has a rectangular bar shape extending in the vertical direction. As shown in FIG. 9, the base portion 231 has a base hole 231H and a rail 231R. The base hole 231H is a rectangular hole formed inside the base portion 231. The base hole 231H extends in the vertical direction and is a hole penetrating in the first direction. The rail 231R extends in the vertical direction and is formed on the inner walls on both sides of the base hole 231H, respectively. The rail 231R engages with a groove DU32 formed on the convex portion DU31 of the duct DU. By the rail 231R engaging with the groove DU32, the third link 230 is slidable in the vertical direction.

[0089] The third hole 232 is a rectangular hole located at the upper end of the third link 230. As shown in FIG. 6, the third protrusion 224 of the second link 220 enters the third hole 232. Thereby, when the second link 220 rotates, the third link 230 slides vertically.

[0090] The shoot pressing part 233 has a pressing surface 233A that presses the movable shoot SH downward. The pressing surface 233A presses the movable shoot SH toward the guide surface 122A side, that is, from above. The shoot pressing part 233 is located at the lower end of the third link 230. When the third link 230 moves downward, the shoot pressing part 233 contacts the pressed part 124 of the movable shoot SH and presses the movable shoot SH downward.

[0091] The coil spring 250 is a tension spring and constantly pulls the second link 220 toward the other side in the first direction. Further, the coil spring 250 constantly pulls the first link 210 toward the other side in the first direction via the second link 220.

[0092] As shown in FIG. 7, when no ON signal is sent from the control unit CU, the movable part 152 is located at the forward position. When an ON signal is sent from the control unit CU, the movable part 152 is pulled from the forward position to the retracted position and moves. As shown in FIG. 8, when the movable part 152 moves from the forward position to the retracted position, the first link 210 slides and moves toward one side in the first direction together with the movable part 152. When the first link 210 slides and moves toward one side in the first direction, the second protruding part 223 of the second link 220 is pushed toward one side in the first direction by the first link 210. When the second protruding part 223 is pushed toward one side in the first direction, the second link 220 rotates clockwise in FIG. 8. When the second link 220 rotates clockwise, the third protruding part 224 pushes the third link 230 downward. When the third link 230 is pushed downward, the third link 230 pushes the pressed part 124 of the movable shoot SH downward. As a result, the movable shoot SH moves from the first position to the second position.

[0093] On the one hand, when the ON signal is no longer sent from the control unit CU, due to the biasing force of the coil spring 250, the second link 220 rotates counterclockwise from the state shown in FIG. 8. When the second link 220 rotates counterclockwise, as shown in FIG. 7, the third link 230 is pulled upward by the third protrusion 224 of the second link 220. When the third link 230 is pulled upward, the third link 230 moves from the pressing position to the allowable position, so that the shoot pressing portion 233 does not press the pressed portion 124 of the movable shoot SH. When the third link 230 moves to the allowable position, due to the biasing force of the spring 130, the movable shoot SH moves from the second position to the first position. Further, when the second link 220 rotates counterclockwise, the first link 210 is pulled to the other side in the first direction by the second protrusion 223 of the second link 220. When the first link 210 is pulled to the other side in the first direction, the movable part 152 is pulled to the other side in the first direction together with the first link 210 and returns to the forward position.

[0094] The control unit CU includes a CPU, a RAM, a ROM, an input / output circuit, etc., and executes control by performing various arithmetic processes based on programs and data stored in the ROM, etc. In the present embodiment, the control unit CU controls the solenoid actuator 150 to move the movable shoot SH only between the first position and the second position. Specifically, every time the control unit CU forms an image of one sheet of the sheet S, before the front end of the sheet S reaches the fixing device 6, the control unit CU turns off the solenoid actuator 150 to position the movable shoot SH at the first position. Then, every time the control unit CU forms an image of one sheet of the sheet S, after the front end of the sheet S reaches the fixing device 6, the control unit CU turns on the solenoid actuator 150 to move the movable shoot SH from the first position shown in FIG. 2 to the second position shown in FIG. 3.

[0095] Specifically, when the control unit CU is not performing printing control, it turns off the solenoid actuator 150 to position the movable chute SH at the first position. When the control unit CU receives a printing command and it reaches the timing after the front end of the sheet S reaches the fixing device 6, it turns on the solenoid actuator 150 to move the movable chute SH to the second position.

[0096] When the printing control is completed, the control unit CU turns off the solenoid actuator 150 to move the movable chute SH to the first position. When the control unit CU prints a plurality of sheets S, it repeats the above-described operation for each sheet S. Further, when the control unit CU determines that the sheet S is jammed during the conveyance of the sheet S, it turns off the solenoid actuator 150 to position the movable chute SH at the first position. The determination of whether the sheet S is jammed may be made based on, for example, a signal from a sheet sensor that detects the presence or absence of the sheet S.

[0097] Since the movable part 152 of the solenoid actuator 150 can only move between the forward position and the retracted position, the control unit CU cannot move the movable chute SH from the second position to the third position. However, the movable chute SH can be moved from the second position to the third position by human force.

[0098] Specifically, when the movable chute SH is in the first position, it cannot move upward by contacting the duct DU, but can move downward. Also, when the movable chute SH is in the second position, it cannot move upward by contacting the link mechanism 200, but can move downward. Further, when the movable chute SH is in the third position, it cannot move downward by contacting the base portion 110 of the guide member 100, but can move upward.

[0099] In this embodiment, when the control unit CU is not performing printing control, the movable chute SH is located at the first position. Therefore, when performing a jam process to remove the sheet S jammed in the image forming apparatus 1, the movable chute SH can be moved by a user operation in a direction from the first position toward the third position. Further, since the movable chute SH is not connected to the moving device TM and is simply configured such that its upper surface contacts the moving device TM, it can be moved in a direction from the first position toward the third position with the moving device TM stopped.

[0100] As shown in FIGS. 10 and 11, the fixing device 6 further includes a fixing shutter 500 that opens and closes the opening 63A of the fixing housing 63, and a shutter operating mechanism 900 for opening and closing the fixing shutter 500. The opening 63A of the fixing housing 63 is an opening through which the sheet S conveyed toward the fixing nip NP2 passes. The opening 63A is located upstream of the fixing nip NP2 in the conveyance direction.

[0101] The fixing shutter 500 is rotatable between a closed position shown in FIG. 10 and an open position shown in FIG. 11. When the fixing shutter 500 is in the closed position, it closes the opening 63A. When the fixing shutter 500 is in the open position, it opens the opening 63A. Both end portions of the fixing shutter 500 in the first direction are rotatably supported by the fixing housing 63. The fixing shutter 500 has a protrusion 540 at the other end in the first direction. The protrusion 540 is located at a position different from the rotation center of the fixing shutter 500.

[0102] As shown in FIG. 12, the shutter operating mechanism 900 includes a shutter arm 910, an arm cam 920, and a spring 930. The shutter arm 910 and the arm cam 920 are made of resin or the like. The spring 930 is made of metal or the like.

[0103] The shutter arm 910 has a function of rotating the fixing shutter 500 between a closed position and an open position by rotating about the arm axis X6 (see FIGS. 10 and 11). The shutter arm 910 includes an arm main body 911, a first connecting portion 912, and a second connecting portion 913. The arm main body 911, the first connecting portion 912, and the second connecting portion 913 are integrally formed.

[0104] The first connecting portion 912 has a hole H3 into which the cylindrical portion 921 of the arm cam 920 fits. The first connecting portion 912 is rotatably supported by the shaft SF via the cylindrical portion 921. Note that the shaft SF is supported by the fixing housing 63.

[0105] The second connecting portion 913 has a long hole H4 into which the protrusion 540 of the fixing shutter 500 fits. The second connecting portion 913 is connected to the protrusion 540 of the fixing shutter 500 by the long hole H4.

[0106] The arm main body 911 connects the first connecting portion 912 and the second connecting portion 913. The arm main body 911 has a boss B1 that protrudes to the other side in the first direction.

[0107] The arm cam 920 is a cam that presses the shutter arm 910 at a position deviated from the arm axis X6 by rotating about the arm axis X6, and rotates the shutter arm 910 about the arm axis X6. Specifically, the arm cam 920 presses the boss B1 of the shutter arm 910 in the circumferential direction. Here, the circumferential direction is the direction along a circle centered on the arm axis X6. The arm cam 920 includes a cylindrical portion 921, a pressing portion 922, a boss B2, and a connecting portion 923. The cylindrical portion 921, the pressing portion 922, the boss B2, and the connecting portion 923 are integrally formed. The pressing portion 922 and the boss B2 are connected to the cylindrical portion 921 by the connecting portion 923.

[0108] The cylindrical portion 921 has a hole H5 into which the shaft SF enters. The cylindrical portion 921 is rotatably supported by the shaft SF. The cylindrical portion 921 enters the hole H3 of the shutter arm 910. The cylindrical portion 921 rotatably supports the shutter arm 910.

[0109] The boss B2 is a portion where a force is input from a connecting link 700 (see FIG. 17) described later. The boss B2 is located at a position different from the arm axis X6 in a direction orthogonal to the first direction. The boss B2 protrudes to the other side in the first direction.

[0110] The pressing portion 922 is located at a position displaced from the arm axis X6. The pressing portion 922 has a long hole H6 into which the boss B1 of the shutter arm 910 enters. The long hole H6 is in an arc shape centered on the arm axis X6. The long hole H6 allows displacement of the boss B1 of the shutter arm 910. The pressing portion 922 is in a cylindrical shape along the arc-shaped long hole H6. As shown in FIG. 10, one end portion of the pressing portion 922 in the first direction is a spring contact portion T that can contact the spring 930 in the rotation direction of the arm cam 920 due to a part of one end side of the long hole H6 being cut out.

[0111] As shown in FIG. 13(b), the spring 930 is a torsion spring and has a coil portion 931, a first arm portion 932, and a second arm portion 933. The cylindrical portion 921 of the arm cam 920 is inside the coil portion 931. The cylindrical portion 921 supports the coil portion 931. The angle formed by the first arm portion 932 and the second arm portion 933 is an acute angle.

[0112] The spring contact portion T is located between the first arm portion 932 and the second arm portion 933. The spring contact portion T has a first contact surface T1 and a concave portion T3. The first contact surface T1 is a surface that can contact the first arm portion 932 in the rotation direction of the arm cam 920.

[0113] The recess T3 has a shape obtained by cutting out a part of the long hole H6 shown in FIG. 13(a). The recess T3 opens toward the second arm portion 933. The boss B1 of the shutter arm 910 is movable within the recess T3. The bottom surface of the recess T3 serves as a second contact surface T2 that can contact the boss B1 of the shutter arm 910 in the rotational direction of the arm cam 920. In the rotational direction of the arm cam 920, the second contact surface T2 is located between the first contact surface T1 and the boss B1. Also, the boss B1 is located between the second contact surface T2 and the second arm portion 933 in the rotational direction of the arm cam 920.

[0114] As shown in FIG. 13(a), when the fixing shutter 500 is in the closed position, as shown in FIG. 13(b), the first contact surface T1 of the arm cam 920 contacts the first arm portion 932, and the second arm portion 933 contacts the boss B1 of the shutter arm 910. The position where the second arm portion 933 contacts the boss B1 of the shutter arm 910 is a position shifted from the arm axis X6. Thereby, the arm cam 920 presses the shutter arm 910 via the spring 930, positioning the fixing shutter 500 in the closed position.

[0115] As shown in FIG. 14(a), when the fixing shutter 500 is in the open position, as shown in FIG. 14(b), the second contact surface T2 of the arm cam 920 contacts the boss B1 of the shutter arm 910. The position where the second contact surface T2 contacts the boss B1 of the shutter arm 910 is a position shifted from the arm axis X6. Thereby, the arm cam 920 contacts the shutter arm 910, positioning the fixing shutter 500 in the open position.

[0116] As shown in FIGS. 15 and 17, the image forming apparatus 1 further includes a connecting link 700. In FIG. 15, the arm cam 920 of the fixing device 6 is illustrated representatively, and other parts of the fixing device 6 are omitted.

[0117] As shown in FIG. 16, the photosensitive drum 51 has a drum shaft 51A. The drum shaft 51A is located at the center of rotation of the photosensitive drum 51. As shown in FIG. 15, the main body housing 2 has a guide rail 2G that guides the drum shaft 51A in the process of attaching and detaching the process cartridge 50 to and from the main body housing 2.

[0118] As shown in FIG. 17, the connecting link 700 is a mechanism that rotates the fixing shutter 500 from the closed position to the open position in the process of mounting the process cartridge 50 to the main body housing 2, and rotates the fixing shutter 500 from the open position to the closed position in the process of removing the process cartridge 50 from the main body housing 2. The connecting link 700 includes a contact piece 710, a first rotating link 720, a linear motion link 730, and a second rotating link 740.

[0119] The contact piece 710 is in contact with the drum shaft 51A and is movable. The contact piece 710 is movably supported by a contact piece rail (not shown). The contact piece rail is provided on the main body housing 2 or the like.

[0120] The contact piece 710 has a main body portion 711, a first protrusion 712, and a second protrusion 713. The first protrusion 712 and the second protrusion 713 protrude from the main body portion 711 in the first direction.

[0121] The first protrusion 712 contacts the drum shaft 51A when the process cartridge 50 is mounted on the main body housing 2. The second protrusion 713 contacts the drum shaft 51A when the process cartridge 50 is detached from the main body housing 2.

[0122] In the present embodiment, the contact piece 710 is configured to move in contact with the drum shaft 51A. However, a guide protrusion different from the drum shaft 51A may be formed on the process cartridge 50, and the contact piece 710 may be configured to move in contact with the guide protrusion.

[0123] The first swing link 720 is a substantially linear member connected to the contact piece 710 and the linear motion link 730. One end of the first swing link 720 rotatably supports the main body portion 711 of the contact piece 710.

[0124] The linear motion link 730 is a substantially linear member connected to the first swing link 720 and the second swing link 740. The linear motion link 730 is movable in the front-rear direction with respect to the main body housing 2. One end of the linear motion link 730 rotatably supports the first swing link 720. The other end of the linear motion link 730 has a long hole H7 extending in the vertical direction.

[0125] The second swing link 740 is connected to the linear motion link 730 and is rotatably supported by the main body housing 2 about the link axis X7. The second swing link 740 has a support portion 741 rotatably supported by the main body housing 2, a first arm 742 extending substantially downward from the support portion 741, and a second arm 743 extending substantially upward from the support portion 741.

[0126] The first arm 742 has a boss B3 that fits into the long hole H7 of the linear motion link 730. The second arm 743 has a long hole H8. The long hole H8 is arc-shaped about the link axis X7.

[0127] The boss B2 of the arm cam 920 fits into the long hole H8 of the second swing link 740. Thus, the force input to the contact piece 710 is transmitted to the arm cam 920 via the first swing link 720, the linear motion link 730, and the second swing link 740.

[0128] The image forming apparatus 1 further includes a lock 300 for holding the fixing shutter 500 in the open position or the closed position. Specifically, the lock 300 restricts the movement of the linear motion link 730 in the second direction by pressing the linear motion link 730. The lock 300 has a lock arm 310 that contacts the linear motion link 730 and a lock spring 320 that biases the lock arm 310 toward the linear motion link 730.

[0129] The lock arm 310 is rotatably supported by the main body housing 2 about the lock axis X5. The linear motion link 730 has a link projection 731 protruding toward the lock 300 side. The tip 311 of the lock arm 310 can overcome the link projection 731 against the biasing force of the lock spring 320 as the linear motion link 730 moves in the second direction.

[0130] When the tip 311 of the lock arm 310 is located on one side in the second direction with respect to the link projection 731, the movement of the linear motion link 730 in one side in the second direction is restricted. When the tip 311 of the lock arm 310 is located on the other side in the second direction with respect to the link projection 731, the movement of the linear motion link 730 in the other side in the second direction is restricted.

[0131] Next, the operations of the shutter operating mechanism 900 and the connecting link 700 will be described. First, the operations of the shutter operating mechanism 900 and the connecting link 700 when the process cartridge 50 is attached to the main body housing 2 will be described. In the following description, the position of the arm cam 920 when the fixing shutter 500 is in the closed position is also referred to as the "closed corresponding position", and the position of the arm cam 920 when the fixing shutter 500 is in the open position is also referred to as the "open corresponding position".

[0132] As shown in FIG. 17, when the drum shaft 51A of the process cartridge 50 is inserted into the guide rail 2G of the main body housing 2, the drum shaft 51A abuts against the first projection 712 of the contact piece 710 and pushes the contact piece 710 to one side in the second direction. As a result, as shown in FIG. 18, the force applied from the drum shaft 51A to the contact piece 710 is transmitted to the second rotating link 740 via the first rotating link 720 and the linear motion link 730, and the second rotating link 740 rotates clockwise in the drawing.

[0133] When the second rotating link 740 rotates clockwise in the drawing, the second rotating link 740 pushes the boss B2 of the arm cam 920, causing the arm cam 920 to rotate from the closed corresponding position to the open corresponding position.

[0134] In the process of the arm cam 920 rotating from the closed corresponding position to the open corresponding position, as shown in FIG. 14(b), the second contact surface T2 of the arm cam 920 pushes the boss B1 of the shutter arm 910, so that the shutter arm 910 rotates from the position shown in FIG. 13(a) to the position shown in FIG. 14(a). As a result, the fixing shutter 500 connected to the shutter arm 910 rotates from the closed position to the open position.

[0135] As shown in FIG. 19, when the process cartridge 50 mounted on the main body housing 2 is removed from the main body housing 2, the drum shaft 51A moves along the guide rail 2G and abuts against the second protrusion 713 of the contact piece 710, pushing the contact piece 710 to the other side in the second direction. As a result, the force applied from the drum shaft 51A to the contact piece 710 is transmitted to the second rotation link 740 via the first rotation link 720 and the linear motion link 730, and the second rotation link 740 rotates counterclockwise as shown in the figure.

[0136] When the second rotation link 740 rotates counterclockwise as shown in the figure, the second rotation link 740 pushes the boss B2 of the arm cam 920, so that the arm cam 920 rotates from the open corresponding position to the closed corresponding position.

[0137] In the process of the arm cam 920 rotating from the open corresponding position to the closed corresponding position, as shown in FIG. 13(b), the first contact surface T1 of the arm cam 920 pushes the boss B1 of the shutter arm 910 via the spring 930, so that the shutter arm 910 rotates from the position shown in FIG. 14(a) to the position shown in FIG. 13(a). As a result, the fixing shutter 500 connected to the shutter arm 910 rotates from the open position to the closed position.

[0138] Next, the function and effect of the movable chute SH when the user performs jam processing will be described. As shown in FIG. 1, when the sheet S jams during fixing by the fixing device 6, the control unit CU turns off the solenoid actuator 150 and rotates the movable chute SH from the second position to the first position. After that, when the user opens the front cover 23 and removes the process cartridge 50 from the main body housing 2, the fixing shutter 500 rotates from the open position to the closed position by the connecting link 700 shown in FIG. 19.

[0139] As shown in FIG. 20, when the rear end of the sheet S jammed in the fixing device 6 is located at the upstream position P1 on the upstream side in the conveyance direction with respect to the front surface FD of the duct DU, the rear end of the sheet S is lifted by the tip of the movable chute SH located at the first position, so that a gap is formed between the rear end of the sheet S and the upper surface of the movable chute SH. Therefore, it becomes easier for the user to grasp the rear end of the sheet S, and the jam processing can be easily performed. Here, the front surface FD of the duct DU is the surface facing the process cartridge 50 in the conveyance direction.

[0140] Also, when the rear end of the sheet S jammed in the fixing device 6 is located at the downstream position P2 on the downstream side in the conveyance direction with respect to the front surface FD of the duct DU, the user pushes down the movable chute SH from the first position to the third position. As a result, the sheet S supported by the tip of the movable chute SH comes down. Therefore, it becomes easier for the user to grasp the rear end of the sheet S, and the jam processing can be easily performed.

[0141] Next, the structure and method for attaching the chute sheet metal 410 of the movable chute SH to the chute main body 120 will be described in detail. As shown in FIG. 21, the movable chute SH includes a chute main body 120, a chute sheet metal 410, and a mounting member 420.

[0142] The chute main body 120 is made of a material containing polyethylene terephthalate (PET) and glass resin. The chute sheet metal 410 is made of metal. The mounting member 420 is made of ABS resin.

[0143] Here, the material of the chute body 120 described above is more likely to discharge electricity than the ABS resin. As a result, even when the charged sheet S comes into contact with the chute body 120, the chute body 120 is less likely to be charged, so the discharge between the chute body 120 and the sheet S is suppressed, and the image of the sheet S is prevented from being disturbed. However, the material of the chute body 120 has lower rigidity than the ABS resin. Therefore, by overlapping the chute sheet metal 410 on the chute body 120, the rigidity of the chute body 120 is increased.

[0144] The chute body 120 has the base portion 121, the guide ribs 122, etc. described above, and further has a plurality of ribs 126 for positioning the chute sheet metal 410 in the third direction. The rib 126 protrudes upward from the base portion 121. The plurality of ribs 126 are distributed and arranged at the upstream and downstream ends of the base portion 121 in the conveying direction. The plurality of ribs 126 are each located between two guide ribs 122.

[0145] The guide ribs 122 of the chute body 120 protrude from the base portion 121 to the downstream side and the upstream side in the conveying direction.

[0146] As shown in FIGS. 21 and 22, the chute sheet metal 410 has a base portion 411, an upstream flange 412, a downstream flange 413, and a plurality of slits 414. The base portion 411 is curved so as to follow the curved base portion 121 of the chute body 120. The base portion 411 has a front surface F3 and a back surface F4.

[0147] The front surface F3 is located at the upper end of the base portion 411. The front surface F3 faces the surface of the sheet S when the sheet S is being conveyed by the guide rib 122.

[0148] The back surface F4 is located at the lower end of the base portion 411. The back surface F4 contacts the rib 126 of the chute body 120 (see FIGS. 24 and 26).

[0149] The upstream flange 412 extends downward from the upstream end of the base portion 411 in the conveyance direction and then extends upstream in the conveyance direction. The downstream flange 413 extends downward from the downstream end of the base portion 411 in the conveyance direction (see also Fig. 26).

[0150] The slit 414 is a hole that allows the guide rib 122 of the chute body 120 to pass through. The slit 414 extends from the upstream flange 412 through the base portion 411 to the downstream flange 413. The end on the downstream side of the slit 414 gradually widens in width as it goes downstream in the conveyance direction.

[0151] Each end of the slit 414 in the conveyance direction is located below the guide rib 122 and can be engaged with the guide rib 122 from below. Thereby, the chute sheet metal 410 is prevented from moving upward with respect to the chute body 120.

[0152] As shown in Figs. 23(a) and (b), the chute body 120 has a first positioning surface F5 and a second positioning surface F6 for positioning the chute sheet metal 410 in the first direction. The first positioning surface F5 and the second positioning surface F6 are orthogonal to the first direction. The first positioning surface F5 faces one side in the first direction. The second positioning surface F6 faces the other side in the first direction.

[0153] The first positioning surface F5 is located on one side in the first direction with respect to the two middle guide ribs 122 among the plurality of guide ribs 122. The second positioning surface F6 is located on the other side in the first direction with respect to the two middle guide ribs 122 among the plurality of guide ribs 122.

[0154] In the following description, among the two middle guide ribs 122, the guide rib 122 on one side in the first direction is also referred to as the first guide rib L1, and the guide rib 122 on the other side in the first direction is also referred to as the second guide rib L2. Also, the slit 414 into which the first guide rib L1 enters is also referred to as the first slit S1, and the slit 414 into which the second guide rib L2 enters is also referred to as the second slit S2.

[0155] The first positioning surface F5 and the second positioning surface F6 are each in contact with the edge in the first direction of the slit 414 of the chute sheet metal 410. Specifically, the first positioning surface F5 is in contact with the edge on one side in the first direction of the first slit S1. The second positioning surface F6 is in contact with the edge on the other side in the first direction of the second slit S2.

[0156] As shown in FIGS. 21 and 25, the mounting member 420 is an elongated member whose dimension in the first direction is larger than the dimensions in the second and third directions. The dimension of the mounting member 420 in the first direction is smaller than the dimension of the chute body 120 in the first direction.

[0157] The mounting member 420 has a first portion 421, a second portion 422, and an arm portion 423. The first portion 421 is located at one end of the mounting member 420 in the first direction. The second portion 422 is located at the other end of the mounting member 420 in the first direction. The arm portion 423 is located between the first portion 421 and the second portion 422 in the first direction.

[0158] The arm portion 423 extends in the first direction. The arm portion 423 is elastically deformable in the third direction.

[0159] As shown in FIG. 25, the chute body 120 further has a first holding portion 127 that holds the first portion 421 of the mounting member 420, a second holding portion 128 that holds the second portion 422 of the mounting member 420, and an engagement hole H9 that engages with the tip of the arm portion 423.

[0160] The first holding portion 127 has a first wall W1 that protrudes downward from the base portion 121 and a second wall W2 that protrudes downstream in the conveyance direction from the lower end of the first wall W1. The second holding portion 128 has a structure substantially the same as that of the first holding portion 127 and has the first wall W1 and the second wall W2.

[0161] As shown in Fig. 26, the first part 421 of the mounting member 420 is sandwiched between the base part 411 of the chute sheet metal 410 and the second wall W2 of the first holding part 127. The first part 421 of the mounting member 420 is sandwiched between the downstream flange 413 of the chute sheet metal 410 and the first wall W1 of the chute body 120.

[0162] As shown in Fig. 27(a), the downstream flange 413 of the chute sheet metal 410 is in contact with the inclined surface F7 of the guide rib 122. Thereby, the movement of the chute sheet metal 410 toward the downstream side in the conveying direction is stopped.

[0163] As shown in Fig. 27(b), the second part 422 of the mounting member 420 is sandwiched between the base part 411 of the chute sheet metal 410 and the second wall W2 of the second holding part 128. As shown in Fig. 27(a), the second part 422 of the mounting member 420 is sandwiched between the downstream flange 413 of the chute sheet metal 410 and the first wall W1 of the chute body 120.

[0164] As shown in Fig. 27(a) and (b), the first holding part 127 and the second holding part 128 each further have a third wall W3. The third wall W3 is located at the other end of the first wall W1 in the first direction and connects the second wall W2 and the base part 121.

[0165] As shown in Fig. 27(b), the tip of the arm part 423 is movable between the first arm position shown by the two-dot chain line and the second arm position shown by the solid line. The first arm position is the position of the tip of the arm part 423 before the mounting member 420 is attached to the chute body 120 and the chute sheet metal 410. The second arm position is the position of the tip of the arm part 423 after the mounting member 420 is attached to the chute body 120 and the chute sheet metal 410.

[0166] When the tip of the arm portion 423 is located at the second arm position, it engages with the engagement hole H9. When the arm portion 423 is engaged with the engagement hole H9, the arm portion 423 is in a deflected state. Thereby, due to the elastic force by which the arm portion 423 tries to return to the first arm position, the mounting member 420 is biased toward the other side in the first direction, and the first portion 421 and the second portion 422 are respectively pressed against the corresponding third wall W3, and the mounting member 420 is positioned in the first direction.

[0167] Next, a method of attaching the chute sheet metal 410 to the chute body 120 using the mounting member 420 will be described. As shown in FIG. 21, the operator inserts the downstream ends of the plurality of guide ribs 122 of the chute body 120 into the downstream ends of the corresponding slits 414 of the chute sheet metal 410 respectively, so as to turn the downstream end of the slit 414 under the guide rib 122. Thereafter, the operator inserts the upstream ends of the plurality of guide ribs 122 into the upstream ends of the corresponding slits 414 respectively, so as to turn the upstream end of the slit 414 under the guide rib 122. In this way, when trying to move the chute sheet metal 410 upward by turning the downstream end and the upstream end of the slit 414 under the guide rib 122, the downstream end and the upstream end of the slit 414 engage with the guide rib 122, and it is suppressed that the chute sheet metal 410 comes off upward from the chute body 120.

[0168] Thereafter, the operator moves the chute sheet metal 410 downstream in the conveyance direction, so that the downstream end of the slit 414 contacts the inclined surface F7 of the guide rib 122. Thereby, the chute sheet metal 410 is temporarily positioned in the conveyance direction with respect to the chute body 120.

[0169] Also, in this state, since the back surface F4 of the chute sheet metal 410 is in contact with the rib 126 of the chute body 120 (see also Fig. 24 etc.), the chute sheet metal 410 is positioned in the third direction with respect to the chute body 120. Further, when passing each guide rib 122 through the corresponding slit 414, as shown in Figs. 23(a) and (b), the operator brings the edge on one side in the first direction of the first slit S1 into contact with the first positioning surface F5, and brings the edge on the other side in the first direction of the second slit S2 into contact with the second positioning surface F6. Thereby, the chute sheet metal 410 is positioned in the first direction with respect to the chute body 120.

[0170] Thereafter, as shown in Figs. 25 and 27(b), the operator arranges the first part 421 and the second part 422 at positions shifted to one side in the first direction of the second wall W2 respectively, and then moves the attachment member 420 to the other side in the first direction. Thereby, the first part 421 and the second part 422 enter between the first wall W1 and the downstream flange 413 of the chute sheet metal 410 and between the second wall W2 and the base portion 411 of the chute sheet metal 410 respectively.

[0171] When the first part 421 and the second part 422 enter between the first wall W1 and the downstream flange 413 respectively, as shown in Fig. 26, even if an attempt is made to move the chute sheet metal 410 upstream in the conveying direction, the downstream flange 413 engages with the first part 421 etc., thereby suppressing the chute sheet metal 410 from coming off upstream in the conveying direction from the chute body 120. Also, when the first part 421 and the second part 422 enter between the first wall W1 and the downstream flange 413 respectively, the movement of the attachment member 420 in the conveying direction is stopped.

[0172] When the first part 421 and the second part 422 enter between the second wall W2 and the base portion 411 of the chute sheet metal 410 respectively, the movement of the attachment member 420 in the third direction is stopped.

[0173] Thereafter, as shown in FIG. 27(b), the operator bends the arm portion 423 while engaging the tip of the arm portion 423 with the engagement hole H9. As a result, the attachment member 420 is biased toward the other side in the first direction by the elastic force of the arm portion 423, and the first portion 421 and the second portion 422 are pressed against the corresponding third wall W3, respectively, so that the attachment member 420 is positioned in the first direction.

[0174] As described above, according to the present embodiment, the following effects can be obtained. Since the movable chute SH can move to a third position farther from the second position with respect to the straight line LN, the movable chute SH can move in a range larger than the range in which the movable chute SH is moved by the control unit CU. Therefore, the space for the user to put their hand during jam processing can be widened.

[0175] When the moving device TM is stopped, the movable chute SH can move in the direction from the first position toward the third position. Therefore, when moving the movable chute SH to the third position, the moving device TM does not become a resistance, so that the movable chute SH can be moved smoothly.

[0176] By configuring the spring 130 to bias the movable chute SH toward the first position, when the user strongly presses the movable chute SH from the first position toward the third position, the spring 130 can suppress the moving speed of the movable chute SH from becoming too high.

[0177] When the sheet S jams during conveyance of the sheet S, by configuring the movable chute SH to be located at the first position, when the sheet S is located between the transfer nip NP1 and the fixing nip NP2, the sheet S that contacts the movable chute SH is located near the straight line LN, so that it is easy for the user to grasp the sheet S.

[0178] By configuring the moving device TM to press the movable chute SH from the guide surface 122A side, it is not necessary to arrange the moving device TM in the space on the third position side with respect to the movable chute SH located at the first position. Therefore, the movable chute SH can be moved smoothly.

[0179] By configuring the link mechanism 200 to push the movable chute SH, the amount of movement of the movable chute SH from the first position to the second position can be increased.

[0180] By configuring the tip of the movable chute SH located at the first position to be above the transfer roller 53, when the sheet S is jammed while being located between the transfer nip NP1 and the fixing nip NP2, the tip of the movable chute SH located at the first position supports the sheet S, so that the user can easily grasp the rear end of the sheet S. Further, in a state where the sheet S is supported by the tip of the movable chute SH located at the first position, a space is likely to be formed between the movable chute SH and the sheet S, so that the user can easily insert a finger into the space and grasp the sheet S.

[0181] By configuring the fixing device 6 to include the fixing shutter 500, it is possible to suppress the user's hand from entering the fixing housing 63 during jam processing when the sheet S is jammed while being located between the transfer nip NP1 and the fixing nip NP2 by the fixing shutter 500.

[0182] By configuring the fixing shutter 500 to open and close in conjunction with the attachment and detachment of the process cartridge 50, when the user removes the process cartridge 50 from the main body housing 2 during jam processing when the sheet S is jammed while being located between the transfer nip NP1 and the fixing nip NP2, the fixing shutter 500 closes, so that it is possible to more reliably suppress the user's hand from entering the fixing housing 63.

[0183] Note that the present disclosure is not limited to the above-described embodiment, and can be used in various forms as exemplified below.

[0184] The toner image carrier is not limited to the photosensitive drum. The toner image carrier may be, for example, an intermediate transfer belt onto which the toner image is transferred from the photosensitive drum. In this case, the transfer roller transfers the toner image on the intermediate transfer belt to the sheet. The transfer roller forms a transfer nip with the intermediate transfer belt.

[0185] The cartridge is not limited to the process cartridge 50. The cartridge may not include, for example, a transfer roller.

[0186] The heating rotator may be a heating roller. The pressurizing rotator may be an endless belt sandwiched between a heating roller and a rubber pad.

[0187] The second position may be a position above the first position. The third position may be a position above the second position. In this case, the moving device may push the movable chute upward. Also, in this case, since the moving device supports the movable chute from below, a spring for biasing the movable chute to the first position may not be provided.

[0188] The moving device may be configured to include a motor and a rack and pinion mechanism. The moving device may be connected to the movable chute. In this case, when the user moves the movable chute, the moving device may move together.

[0189] The spring is not limited to a torsion spring, and may be a compression coil spring, a tension coil spring, a leaf spring, or the like.

[0190] When the control unit determines that the sheet is jammed during sheet conveyance, the control unit may control the moving device to position the movable chute at the second position. Also, when printing control is not being performed, the control unit may position the movable chute at the second position.

[0191] The movable chute may be linearly movable. The tip of the movable chute may face the upstream side in the conveyance direction. The fixing shutter may be linearly movable.

[0192] The image forming apparatus is not limited to a laser printer, and may be, for example, a copying machine, a multifunction machine, or the like.

[0193] Each element described in the above-described embodiments and modified examples may be implemented in any combination.

Explanation of Reference Numerals

[0194] 1 Image forming apparatus 6 Fixing device 51 Photosensitive drum 53 Transfer roller 61 Heating rotating body 62 Pressing rotating body CU Control unit LN Straight line NP1 Transfer nip NP2 Fixing nip S Sheet SH Movable chute TM Moving device

Claims

1. A toner image carrier that carries a toner image, A transfer roller that transfers the toner image on the toner image carrier to a sheet, the transfer roller forming a transfer nip with the toner image carrier, A fixing device for fixing the toner image transferred to the sheet to the sheet, A heating rotating body for heating the sheet, A pressure rotating body for pressing the sheet, the pressure rotating body forming a fixing nip with the heating rotating body, and a fixing device having the same, A movable chute that is disposed downstream of the transfer roller and upstream of the fixing device in the sheet conveyance direction and guides the sheet, and is movable between a first position and a second position that is farther from the first position with respect to a straight line connecting the downstream end of the transfer nip and the upstream end of the fixing nip as viewed from the axial direction of the transfer roller, A moving device for moving the movable chute, A control unit that moves the movable chute only between the first position and the second position by controlling the moving device, and is provided with the same, The movable chute is movable to a third position that is farther from the straight line than the second position, and an image forming apparatus characterized by the same.

2. The movable chute is movable in a direction from the first position toward the third position in a state where the moving device is stopped, and the image forming apparatus according to claim 1 is characterized by the same.

3. The image forming apparatus according to claim 2 further includes a spring that biases the movable chute toward the first position, and is characterized by the same.

4. When the control unit determines that a sheet is jammed during sheet conveyance, the control unit controls the moving device to position the movable chute at the first position, and the image forming apparatus according to claim 1 is characterized by the same.

5. The moving device has a solenoid actuator, The image forming apparatus according to claim 1, wherein the control unit moves the movable chute between the first position and the second position by controlling the solenoid actuator.

6. The movable chute has a guide surface for guiding a sheet, The image forming apparatus according to claim 5, wherein the moving device has a pressing surface for pressing the movable chute from the guide surface side.

7. Further comprising a link mechanism that moves by the driving force of the solenoid actuator, The link mechanism is, A first link having one end connected to the solenoid actuator and movable in the axial direction, A second link connected to the other end of the first link and rotatable about a first axis by the movement of the first link, A third link having the pressing surface, the third link being connected to the second link and pushing the movable chute toward the second position when the second link rotates, the image forming apparatus according to claim 6.

8. The movable chute is rotatable about a second axis and extends downstream in the conveyance direction from the second axis, The second position is a position lower than the first position, When the movable chute is in the first position, the tip of the movable chute is located above the transfer nip, The image forming apparatus according to claim 4, wherein when the movable chute is in the second position, the tip of the movable chute is located below the transfer nip.

9. The downstream end of the movable chute in the conveyance direction is farther from the straight line when the movable chute is in the second position than when it is in the first position, and farther from the straight line when the movable chute is in the third position than when it is in the second position, the image forming apparatus according to claim 1.

10. A transfer roller for transferring a toner image onto a sheet, A fixing device for fixing the toner image transferred onto the sheet to the sheet, A movable chute that is disposed downstream of the transfer roller and upstream of the fixing device in the sheet conveyance direction and guides the sheet, and is movable in order to a first position, a second position, and a third position in a direction intersecting the surface of the sheet, A moving device for moving the movable chute, A control unit that moves the movable chute only between the first position and the second position by controlling the moving device, and an image forming apparatus characterized by comprising the same.

11. The fixing device, A fixing housing having an opening through which a sheet conveyed toward the inside of the fixing device passes, A fixing shutter movable between an open position for opening the opening and a closed position for covering the opening, and the image forming apparatus according to any one of claims 1 to 10, characterized by comprising the same.

12. A main body housing, A cartridge detachably attached to the main body housing, and further comprising, In the process of the cartridge being attached to the main body housing, the fixing shutter moves from the closed position to the open position, In the process of the cartridge being removed from the main body housing, the fixing shutter moves from the open position to the closed position, and the image forming apparatus according to claim 11, characterized by comprising the same.

Images