Sheet conveying device and image forming apparatus

Abstract

The present invention provides a sheet conveying device and an image forming apparatus. The sheet conveying device includes: a conveying unit configured to convey a sheet through a conveying path; a first moving member; a second moving member capable of moving relative to the first moving member; and a detection unit configured to detect the movement of the second moving member. The first moving member includes a first protrusion and is capable of moving between a first protruding position and a first retracted position. The second moving member includes a second protrusion and is capable of moving between a second protruding position and a second retracted position. When the second protrusion is pushed by the sheet, the second moving member is capable of moving from the second protruding position to the second retracted position in a state where the first moving member is located at the first retracted position.

Description

Technical Field

[0001] The present invention relates to a sheet conveying device configured to convey a sheet and an image forming apparatus including the sheet conveying device. Background Art

[0002] Image forming apparatuses such as printers, copiers, and multifunction peripherals include a sheet conveying device configured to convey a sheet as a recording material. In the sheet conveying device, there are times when a sheet gets stuck in the conveying path (i.e., paper jam).

[0003] Japanese Patent Application Laid-Open No. 2016-176986 discusses an image forming apparatus including a sheet discharge sensor for detecting paper jam of a recording material. When the sheet discharge sensor has detected the recording material and the trailing edge of the recording material has not been detected even though the timing at which the trailing edge of the recording material should have passed the sheet discharge sensor has elapsed, the image forming apparatus according to Japanese Patent Application Laid-Open No. 2016-176986 determines that paper jam of the recording material has occurred.

[0004] However, the image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2016-176986 has the following problem: It is impossible to detect paper jam of the recording material before the timing at which the trailing edge of the recording material should have passed the sheet discharge sensor after the sheet discharge sensor has detected the recording material. Summary of the Invention

[0005] An object of the present invention is to provide a sheet conveying device capable of detecting paper jam of a sheet as a recording material at an earlier time point.

[0006] According to one aspect of the present invention, a sheet conveying device includes: a conveying unit configured to convey a sheet through a conveying path; a first moving member including a first protrusion, the first moving member being movable between a first protruding position where the first protrusion protrudes into the conveying path and a first retracted position where the first protrusion retracts from the first protruding position, and the first moving member being configured to move from the first protruding position to the first retracted position when the first protrusion contacts the sheet; a second moving member including a second protrusion, the second moving member being configured to move relative to the first moving member, the second moving member being movable between a second protruding position where the second protrusion protrudes into the conveying path and a second retracted position where the second protrusion retracts from the second protruding position, and the second moving member being configured to move from the second retracted position to the second protruding position when the first moving member moves from the first protruding position to the first retracted position; and a detection unit configured to detect the movement of the second moving member, wherein, when the second protrusion is pushed by the sheet, the second moving member moves from the second protruding position to the second retracted position in a state where the first moving member is located at the first retracted position.

[0007] Other features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic cross-sectional view illustrating an image forming apparatus.

[0009] Figure 2 is a cross-sectional view illustrating a fixing device according to a first exemplary embodiment.

[0010] Figure 3 is an exploded perspective view illustrating a first indicator, a second indicator, and a sheet discharge sensor according to a first exemplary embodiment.

[0011] Figure 4 is a perspective view illustrating a state where a first indicator, a second indicator, and a sheet discharge sensor according to a first exemplary embodiment are assembled together.

[0012] Figure 5 is a cross-sectional view illustrating a fixing device according to a first exemplary embodiment.

[0013] Figure 6 is a cross-sectional view illustrating a fixing device according to a first exemplary embodiment.

[0014] Figure 7It is a diagram showing the detection timing of the sheet discharge sensor according to the first exemplary embodiment.

[0015] Figure 8 It is a cross-sectional view showing a fixing device according to the second exemplary embodiment.

[0016] Figure 9 It is an exploded perspective view showing a first indicator, a second indicator, and a sheet discharge sensor according to the second exemplary embodiment.

[0017] Figure 10 It is a perspective view showing a state in which a first indicator, a second indicator, and a sheet discharge sensor according to the second exemplary embodiment are assembled together.

[0018] Figure 11 It is a cross-sectional view showing a fixing device according to the second exemplary embodiment.

[0019] Figure 12 It is a cross-sectional view showing a fixing device according to the second exemplary embodiment.

[0020] Figure 13 It is a cross-sectional view showing a fixing device according to the second exemplary embodiment.

[0021] Figure 14 It is a diagram showing the detection timing of the sheet discharge sensor according to the second exemplary embodiment.

[0022] Figure 15 It is a schematic diagram showing a control unit. Detailed Description of the Embodiment

[0023] Hereinafter, preferred forms for implementing the present invention will be described in detail with reference to the drawings and exemplary embodiments as examples. Unless otherwise specified, the functions, materials, shapes, and relative positions of the components described in the exemplary embodiments are not intended to limit the scope of the present invention.

[0024] Hereinafter, a first exemplary embodiment of the present invention will be described with reference to the drawings.

[0025] Hereinafter, an image forming apparatus to which four processing cartridges can be attached and detached will be described as an example of the image forming apparatus according to this exemplary embodiment. The number of processing cartridges attached to the image forming apparatus is not limited to four, but is appropriately set according to need.

[0026] Hereinafter, a laser beam printer will be described as an example of the form of the image forming apparatus according to the exemplary embodiment described below.

[0027] (Overall Structure of the Image Forming Apparatus)

[0028] Hereinafter, with reference to Figure 1Describe the overall structure of the image forming apparatus 100. Figure 1 is a schematic cross-sectional view showing the image forming apparatus 100.

[0029] The image forming apparatus 100 includes a sheet feed tray 1, a sheet feed roller 3, a pair of conveyance rollers 4, a secondary transfer roller 6, a pressure roller 14, a heating unit 13, a discharge roller 15, and a driven roller 16. A sheet 2 as a recording material is placed on the sheet feed tray 1. The driven roller 16 is rotated by the discharge roller 15. The sheet 2 is, for example, paper.

[0030] The image forming apparatus 100 includes photosensitive drums (7Y, 7M, 7C, 7K) and developing devices (9Y, 9M, 9C, 9K). The photosensitive drums (7Y, 7M, 7C, 7K) are image bearing members that carry electrostatic latent images. Each of the developing devices (9Y, 9M, 9C, 9K) includes a developing roller that contacts the corresponding photosensitive drum (7Y, 7M, 7C, 7K) to develop the electrostatic latent image thereon.

[0031] A process cartridge that stores yellow toner and includes the photosensitive drum 7Y and the developing device 9Y forms a yellow image on the intermediate transfer belt 11 described below. A process cartridge that stores magenta toner and includes the photosensitive drum 7M and the developing device 9M forms a magenta image on the intermediate transfer belt 11. A process cartridge that stores cyan toner and includes the photosensitive drum 7C and the developing device 9C forms a cyan image on the intermediate transfer belt 11. A process cartridge that stores black toner and includes the photosensitive drum 7K and the developing device 9K forms a black image on the intermediate transfer belt 11. Each process cartridge is detachably attached to the image forming apparatus 100.

[0032] The image forming apparatus 100 includes an exposure device (laser scanner) 8 and an intermediate transfer belt 11. The exposure device (laser scanner) 8 is disposed above the photosensitive drums (7Y, 7M, 7C, 7K), and the intermediate transfer belt 11 is disposed below the photosensitive drums (7Y, 7M, 7C, 7K). Primary transfer units (10Y, 10M, 10C, 10K), a driving roller 5, and a tension roller 12 are disposed inside the intermediate transfer belt 11. The primary transfer units (10Y, 10M, 10C, 10K) are respectively pressed against the photosensitive drums (7Y, 7M, 7C, 7K). The intermediate transfer belt 11 is stretched around the driving roller 5, the tension roller 12, and the primary transfer units (10Y, 10M, 10C, 10K).

[0033] The sheet 2 stored in the sheet feed tray 1 is fed by Figure 1 the sheet feed roller 3 that rotates in the clockwise direction in, and is conveyed to the pair of conveyance rollers 4. The sheet 2 conveyed by the pair of conveyance rollers 4 is conveyed to a transfer nip formed between the driving roller 5 and the secondary transfer roller 6.

[0034] The photosensitive drums (7Y, 7M, 7C, 7K) each rotate counterclockwise along Figure 1 in the direction shown in Figure 1 . The charged photosensitive drums (7Y, 7M, 7C, 7K) are irradiated with laser light from the laser scanner 8, and an electrostatic latent image is formed on each photosensitive drum (7Y, 7M, 7C, 7K). The developing devices (9Y, 9M, 9C, 9K) develop the electrostatic latent image and form a toner image on each photosensitive drum (7Y, 7M, 7C, 7K).

[0035] A voltage is applied to the primary transfer units (10Y, 10M, 10C, 10K) to transfer the toner image formed on the photosensitive drums (7Y, 7M, 7C, 7K) to the intermediate transfer belt 11. The drive roller 5 is driven and rotated Figure 1 in the clockwise direction shown in Figure 1 to move the intermediate transfer belt 11 at a speed substantially the same as the speed at which the surface of the photosensitive drums (7Y, 7M, 7C, 7K) moves.

[0036] In the case of forming a color image, yellow, magenta, cyan, and black toner images are developed on the photosensitive drums (7Y, 7M, 7C, 7K), respectively. The toner images formed on the photosensitive drums (7Y, 7M, 7C, 7K) are sequentially transferred to the intermediate transfer belt 11 by the primary transfer units 10Y, 10M, 10C, and 10K.

[0037] The transferred toner image on the intermediate transfer belt 11 is transferred to the sheet 2 at the transfer nip formed between the drive roller 5 and the secondary transfer roller 6. The process cartridge and the intermediate transfer belt 11 function as an image forming unit for forming an image on the sheet 2. The transfer nip is a transfer portion for transferring the toner image from the image forming unit to the sheet 2.

[0038] The sheet 2 having the transferred toner image thereon is conveyed to the fixing nip formed between the heating unit 13 and the pressure roller 14. At the fixing nip, the sheet 2 and the toner image are heated and pressed to fix the toner image to the sheet 2. The sheet 2 having the toner image fixed thereon is discharged by the discharge roller 15 and the driven roller 16.

[0039] The portion of the image forming apparatus 100 related to the conveyance of the sheet 2 may be referred to as a sheet conveyance apparatus. The sheet feed roller 3, the conveyance roller pair 4, the secondary transfer roller 6, the intermediate transfer belt 11, the pressure roller 14, the heating unit 13, the discharge roller 15, and the driven roller 16 function as a conveyance unit for conveying the sheet 2.

[0040] (Structure of the fixing device)

[0041] The fixing device 200 according to the present exemplary embodiment will be described below. Figure 2 is a cross-sectional view showing the fixing device 200 according to the present exemplary embodiment.

[0042] The image forming apparatus 100 includes a fixing device 200. The fixing device 200 can be referred to as a part of the sheet conveying device that conveys the sheet 2. The fixing device 200 includes a heating unit (heating portion) 13, a pressure roller 14, a discharge roller 15, and a driven roller 16. The fixing device 200 further includes a first indicator 21, a second indicator 22, a sheet discharge sensor 23, and a conveying guide 26. The discharge roller 15 and the driven roller 16 have a function of being a discharge unit that discharges the sheet 2 to the outside of the image forming apparatus 100.

[0043] The heating unit 13 for heating the sheet 2 includes a fixing film 17, a heater 18, a holder 19, and a bracket 20. The fixing film 17 is cylindrical. The heater 18 is in contact with the inner side of the fixing film 17 and heats the fixing film 17. The holder 19 is heat resistant. The fixing film 17 is, for example, a thin-walled cylindrical plastic film with high heat resistance and high thermal conductivity. The heater 18 is a heating element formed by applying a conductor to a metal base material coated with an insulator. The heater 18 receives electric power supplied from a power source (not shown) and generates heat. In a state where the heater 18 is fitted in the groove portion of the holder 19 and fixed, the heater 18 is supported by the holder 19. The fixing film 17 is attached so as to cover the outer peripheries of the heater 18, the holder 19, and the bracket 20, and is capable of rotational movement.

[0044] When the heating unit 13 receives a force from a compression spring, the heating unit 13 contacts the pressure roller 14 with a predetermined pressure and forms a fixing nip. The pressure roller 14 includes a core metal 14a and a heat-resistant elastic layer 14b formed in a roller shape around the outer periphery of the core metal 14a. The heat-resistant elastic layer 14b of the pressure roller 14 has elasticity, so that a fixing nip having a predetermined width in the conveying direction of the sheet 2 is formed between the heating unit 13 and the pressure roller 14. The pressure roller 14 is driven and rotated at a predetermined speed by a drive system (not shown). The rotation of the pressure roller 14 generates frictional force between the fixing film 17 and the pressure roller 14, and the fixing film 17 is rotated by the pressure roller 14.

[0045] In a state where the pressure roller 14 and the fixing film 17 are rotating and the heater 18 is generating heat, the sheet 2 carrying the unfixed toner image is conveyed to the fixing nip between the fixing film 17 and the pressure roller 14. The sheet 2 that has reached the fixing nip is conveyed while the pressure roller 14 and the fixing film 17 sandwich the sheet 2. In this process, the heat from the heater 18 is applied to the sheet 2 through the fixing film 17, and the unfixed toner image is heated and pressed, whereby the heated and pressed toner image is fixed to the sheet 2.

[0046] The curvature of the pressure roller 14 and the fixing film 17 is set such that the sheet 2 separates from the pressure roller 14 and the fixing film 17 after passing through the fixing nip. The sheet 2 is conveyed by the pressure roller 14 and the fixing film 17 to the downstream of the fixing nip.

[0047] The conveyance path 42 is disposed downstream (downstream of the heating unit 13) of the fixing nip along the conveyance direction of the sheet 2. The conveyance path 42 guides the sheet 2 toward a discharge unit downstream (downstream of the fixing nip) of the heating unit 13. The sheet 2 is conveyed by the pressure roller 14 through the conveyance path 42. The sheet 2 passing through the conveyance path 42 contacts a first indicator 21 protruding across the conveyance path 42 and rotates the first indicator 21. Details of the operation of the first indicator 21 will be described below.

[0048] After rotating the first indicator 21, the sheet 2 reaches a sheet discharge nip formed by a discharge roller 15 and a follower roller 16. According to the present exemplary embodiment, a plurality of follower rollers 16 contact the discharge roller 15. The sheet 2 is discharged by the discharge roller 15 and the follower roller 16 to a sheet discharge tray. The sheet discharge tray is formed at the top of the image forming apparatus 100.

[0049] In addition, the fixing device 200 includes a re-conveyance path 43. The sheet 2 that has passed through the conveyance path 42 is guided to the upstream of the conveyance path 42 through the re-conveyance path 43. The sheet 2 after passing through the re-conveyance path 43 is conveyed again to the image forming unit and is conveyed through the fixing nip to the conveyance path 42.

[0050] In the case where an image is to be formed on both sides of the sheet 2, first, one side (front side) of the sheet 2 faces the intermediate transfer belt 11, and an image is formed on the front side of the sheet 2. The sheet 2 having the image formed on the front side is conveyed toward the re-conveyance path 43 through the conveyance path 42. According to the present exemplary embodiment, the sheet 2 is conveyed through the conveyance path 42, and a part of the sheet 2 protrudes from the image forming apparatus 100 toward the sheet discharge tray. In this state, the discharge roller 15 rotates in the reverse direction to convey the sheet 2 to the re-conveyance path 43, with the trailing edge of the sheet 2 on the downstream side.

[0051] The sheet 2 is conveyed through the re-conveyance path 43 and reaches the image forming unit again with the back side of the sheet 2 facing the intermediate transfer belt 11, and an image is formed on the back side of the sheet 2.

[0052] (Details of the sheet detection structure)

[0053] Details will be described below with reference to Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 15Describe a sheet detection structure for detecting a sheet 2.

[0054] Figure 3 is an exploded perspective view showing a first indicator (first moving member) 21, a second indicator (second moving member) 22, and a sheet discharge sensor (detection unit) 23. Figure 4 is a perspective view showing a state in which the first indicator 21, the second indicator 22, and the sheet discharge sensor 23 are assembled together.

[0055] The fixing device 200 of the image forming apparatus 100 includes a first indicator 21, a second indicator 22, and a sheet discharge sensor 23. The sheet discharge sensor 23 is a detection unit configured to detect the movement of the second indicator 22.

[0056] The second indicator 22 is movable relative to the first indicator 21. According to the present exemplary embodiment, the second indicator 22 is attached to the first indicator 21. The first indicator 21 can move between a first protruding position ( Figure 2 ) described below and a first retracted position ( Figure 5 ) where the first indicator 21 is retracted from the first protruding position. The second indicator 22 can move between a second protruding position ( Figure 5 ) described below and a second retracted position ( Figure 2 ) where the second indicator 22 is retracted from the second protruding position.

[0057] As Figure 3 and Figure 4 shown, the first indicator 21 includes a first protrusion 21a, a rotation stopper (support portion, restricting portion) 21b, and a shaft portion 21c. The second indicator 22 includes a second protrusion 22a, a portion to be adjusted (portion to be supported) 22b, a portion to be detected 22c, and a hole 22d. The second indicator 22 is attached to the first indicator 21 by inserting the shaft portion 21c into the hole 22d. The second protrusion 22a is disposed upstream of the first protrusion 21a in the conveyance direction of the sheet 2 in the conveyance path 42.

[0058] In other words, one of the first indicator 21 and the second indicator 22 includes an engaging portion (shaft portion), and the other of the first indicator 21 and the second indicator 22 includes an engaged portion (hole portion) to engage with the engaging portion. The first indicator 21 and the second indicator 22 may respectively include a hole portion and a shaft portion. The first indicator 21 and the second indicator 22 may both include hole portions (engaging portions) to engage with the shaft portion (engaging portion) supported by the conveyance guide 26.

[0059] The first indicator 21 and the second indicator 22 are attached to a conveyance guide (frame member) 26 of the fixing device 200. Specifically, a shaft portion 21c is rotatably supported by the conveyance guide 26, and the second indicator 22 is rotatably supported by the shaft portion 21c. Accordingly, the first indicator 21 and the second indicator 22 are rotatably (swingably) supported about a rotation axis (swing axis, center of rotation) RF. In other words, the first indicator 21 is rotatable about the rotation axis RF, and the second indicator 22 is rotatable about the rotation axis RF.

[0060] According to the present exemplary embodiment, a sheet discharge sensor 23 is attached to the conveyance guide 26. The positions of the first indicator 21, the second indicator 22, and the sheet discharge sensor 23 are determined by the conveyance guide 26 which is a single frame member. In this way, the accuracy of the positions relative to each other is improved.

[0061] Figure 15 is a schematic diagram of a control unit of the sheet conveyance device. The image forming apparatus 100 includes a control unit and a motor M. The control unit is connected to the sheet discharge sensor 23. The motor M is a drive source for driving the conveyance unit. The control unit controls the motor M. The motor M and the control unit may be referred to as part of the sheet conveyance device.

[0062] According to the present exemplary embodiment, the sheet discharge sensor 23 is an optical sensor. When a detected portion 22c of the second indicator 22 is inserted into a slit of the sheet discharge sensor 23, the sheet discharge sensor 23 becomes a light-shielded state. When the detected portion 22c is withdrawn from the slit of the sheet discharge sensor 23, the sheet discharge sensor 23 becomes a light-transmitting state. When the sheet discharge sensor 23 changes between the light-transmitting state and the light-shielded state, a signal output from the sheet discharge sensor 23 changes. Based on the signal change, the control unit detects the movement of the second indicator 22. The control unit controls the motor M to drive the conveyance unit or stop the conveyance unit based on the signal output from the sheet discharge sensor 23.

[0063] An indicator pressing spring (pressing member, first pressing member) 24 is disposed between the first indicator 21 and the second indicator 22. The indicator pressing spring 24 is a torsion spiral spring. The shaft portion 21c is inserted into the indicator pressing spring 24. One end of the indicator pressing spring 24 presses the first indicator 21, and the other end of the indicator pressing spring 24 presses the second indicator 22. In other words, the indicator pressing spring 24 presses the first indicator 21 and the second indicator 22. Accordingly, the adjusted portion 22b of the second indicator 22 abuts against the rotation stopping portion 21b of the first indicator 21, and the rotation stopping portion 21b of the first indicator 21 and the adjusted portion 22b of the second indicator 22 are in contact with each other. When the rotation stopping portion 21b and the adjusted portion 22b are in contact with each other, the first indicator 21 moves from the first protruding position to the first retracted position, and the second indicator 22 integrally with the first indicator 21 moves from the second retracted position to the second protruding position.

[0064] An indicator holding spring (second pressing member, holding pressing member) 25 is attached to the first indicator 21. The indicator holding spring 25 is a torsion spiral spring. The shaft portion 21c is inserted into the indicator holding spring 25. One end of the indicator holding spring 25 presses the conveying guide 26, and the other end presses the first indicator 21. The indicator holding spring 25 generates a pressing force between the first indicator 21 and the conveying guide 26, thereby holding the orientation of the first indicator 21.

[0065] The first protruding portion 21a of the first indicator 21 is in direct contact with the sheet 2. The leading edge roller 29 is rotatably attached to the leading edge of the first protruding portion 21a. The leading edge roller 29 reduces the frictional force acting on the sheet 2.

[0066] The movement of the sheet 2 relative to the first indicator 21 will be described below with reference to Figure 2 and Figure 5 The movement of the sheet 2 relative to the first indicator 21 will be described below with reference to

[0067] Figure 5 FIG. is a cross-sectional view showing the fixing device 200 in a state where the first indicator 21 is moved by the sheet 2.

[0068] When the first indicator 21 is as shown in Figure 2In the state where it is not pushed by the sheet 2, the first indicator 21 is positioned at the first protruding position by the indicator holding spring 25, and the first protrusion 21a protrudes into the conveying path 42. At the same time, the regulating portion 22b of the second indicator 22 is pressed against the rotation stopper 21b of the first indicator 21, and the second indicator 22 is positioned at the second retracted position. In the state where the second indicator 22 is at the second retracted position, the second protrusion 22a retracts from the conveying path 42. The detected portion 22c of the second indicator 22 is located in the slit portion of the sheet discharge sensor 23, and the sheet discharge sensor 23 is in a light-shielded state.

[0069] As Figure 5 shown, when the sheet 2 is conveyed through the fixing nip and comes into contact with the first protrusion 21a of the first indicator 21, the first indicator 21 moves from the first protruding position to the first retracted position. Specifically, the first protrusion 21a is pushed by the sheet 2 conveyed by the pressure roller 14, and the first indicator 21 rotates counterclockwise (first direction) about the rotation axis RF in Figure 2 and Figure 5 .

[0070] The first indicator 21 moves from the first protruding position to the first retracted position.

[0071] As Figure 5 shown, when the first indicator 21 rotates and moves from the first protruding position to the first retracted position, the second indicator 22 moves from the second retracted position to the second protruding position where the second protrusion 22a protrudes into the conveying path 42. Specifically, when the first indicator 21 rotates and moves from the first protruding position to the first retracted position, the second indicator 22 rotates counterclockwise in Figure 2 and Figure 5 integrally with the first indicator 21. Therefore, the second indicator 22 is positioned at the second protruding position as Figure 5 shown.

[0072] In addition, when the first indicator 21 moves from the first protruding position to the first retracted position as Figure 5 shown, the second indicator 22 moves from the second retracted position to the second protruding position, and the detected portion 22c retracts from the slit portion of the sheet discharge sensor 23. Therefore, the sheet discharge sensor 23 changes from the light-shielded state to the light-transmitting state, and the output of the sheet discharge sensor 23 (the signal output from the sheet discharge sensor 23) changes. Based on the output change, the control unit detects the leading edge position of the sheet 2, and in the case where the leading edge position of the sheet 2 is not within the predetermined range, the control unit stops the conveying unit.

[0073] When the sheet 2 jams (paper jam, sheet jam), and the conveyance of the sheet 2 continues, it may be difficult to clear the paper jam. Promptly stopping the conveyance unit will reduce the difficulty for the user to clear the paper jam.

[0074] When the first indicator 21 is pushed by the sheet 2, the second protrusion 22a of the second indicator 22 protrudes into the conveyance path 42. At this time, it is desirable that the protruding amount of the second protrusion 22a is small enough not to contact the normally conveyed sheet 2. In other words, when the second indicator 22 is in the second protruding position, the second protrusion 22a is arranged to be separated from the sheet 2 normally conveyed in the conveyance path 42, and a space is formed between the sheet 2 and the second protrusion 22a.

[0075] In this way, when the sheet 2 is normally conveyed, the sheet 2 is prevented from rubbing against the second protrusion 22a. In addition, when images are printed on both sides of the sheet 2, the second protrusion 22a is prevented from contacting the sheet 2 and removing the printed images from the sheet 2.

[0076] After the sheet 2 is normally conveyed and the trailing edge of the sheet 2 passes the first protrusion 21a, the first indicator 21 pushed by the indicator holding spring 25 rotates clockwise about the rotation axis RF and moves from the first retracted position to the first protruding position. When the first indicator 21 moves from the first retracted position to the first protruding position, the second indicator 22 moves from the second protruding position to the second retracted position. As a result, the sheet discharge sensor 23 is shielded by the detected portion 22c, so that the sheet discharge sensor 23 changes from the light-transmitting state to the light-shielding state, and the output of the sheet discharge sensor 23 (the signal output from the sheet discharge sensor 23) changes. Based on the output change, the control unit detects the trailing edge position of the sheet 2, and when the detected trailing edge position of the sheet 2 is not within the predetermined range, the control unit stops the conveyance unit.

[0077] The following will refer to Figure 6 Describe the behavior in the case of a paper jam after the leading edge of the sheet 2 passes the first indicator 21. Figure 6 is a cross-sectional view showing the fixing device 200 in a state where the sheet 2 is jammed in the conveyance path 42.

[0078] In the case of a paper jam downstream of the first indicator 21, the control unit of the image forming apparatus 100 cannot immediately detect the abnormality. Therefore, the conveyance unit (in this case, the pressure roller 14 and the fixing film 17) continues to convey the sheet 2. Therefore, the sheet 2 is folded in a bellows shape as Figure 6 shown.

[0079] According to this exemplary embodiment, the second protrusion 22a contacts the sheet 2, thereby moving the second indicator 22 from the second protruding position to the second retracted position in a state where the first indicator 21 is in the first retracted position. When viewed along the rotation axis RF, the rotation direction of the first indicator 21 from the first protruding position to the first retracted position is opposite to the rotation direction of the second indicator 22 from the second protruding position to the second retracted position.

[0080] In the case of a paper jam occurring in the conveyance path 42, the accordion-shaped folded sheet 2 contacts the second protrusion 22a of the second indicator 22 at the second protruding position and causes the second indicator 22 to move against the pressing force of the indicator pressing spring 24. In the case where the sheet 2 contacts the second protrusion 22a in a state where the first indicator 21 is in the first retracted position and the second indicator 22 is in the second protruding position, the second indicator 22 moves relative to the first indicator 21 and moves from the second protruding position to the second retracted position. At this time, the second indicator 22 rotates in a direction opposite to the rotation direction of the second indicator 22 in the normal conveyance of the sheet 2, and the regulating portion 22b is separated from the rotation stopper portion 21b.

[0081] Since the first indicator 21 contacts the sheet 2, the movement of the first indicator 21 from the first retracted position to the first protruding position is restricted. However, the second indicator 22 can move from the second protruding position to the second retracted position relative to the first indicator 21. In view of this, in a state where the first indicator 21 is in the first retracted position, the second indicator 22 can move from the second protruding position to the second retracted position.

[0082] Specifically, in a state where the first indicator 21 is in the first retracted position and the second indicator 22 is in the second protruding position, the movement of the second indicator 22 in the direction from the second retracted position to the second protruding position ( Figure 5 the counterclockwise direction in ) is restricted by the rotation stopper portion 21b of the first indicator 21. On the other hand, in the case where the first indicator 21 is in the first retracted position and the second indicator 22 is in the second protruding position, the second indicator 22 is allowed to move in the direction from the second protruding position to the second retracted position ( Figure 5 the clockwise direction in ). In view of this, even in a state where the first indicator 21 is positioned at the first retracted position due to the sheet 2, the second indicator 22 can move from the second protruding position to the second retracted position when the second protrusion 22a is pushed by the sheet 2. Therefore, the second indicator 22 is positioned as Figure 6 shown, and thus the sheet discharge sensor 23 can detect the movement of the second indicator 22.

[0083] When the first indicator 21 moves from the first protruding position to the first retracted position, the pushing force of the indicator pressing spring 24 is large enough to cause the second indicator 22 to move integrally with the first indicator 21 from the second retracted position to the second protruding position. Desirably, the pushing force of the indicator pressing spring 24 is large enough so that the sheet 2 with the lowest stiffness among the sheets 2 used by the image forming apparatus 100 moves the second indicator 22 relative to the first indicator 21 against the pushing force of the indicator pressing spring 24.

[0084] As described above, when a paper jam occurs in the conveyance path 42, the second indicator 22 rotates about the rotation axis RF while the first indicator 21 is in the first protruding position, and the second indicator 22 rotates from the second protruding position to the second retracted position. Accordingly, the detection unit 22c shields the sheet discharge sensor 23, causing the sheet discharge sensor 23 to change from the light-transmitting state to the light-blocking state, and the output (signal output from the sheet discharge sensor 23) of the sheet discharge sensor 23 changes. Specifically, when the sheet 2 is being conveyed normally, the timing at which the sheet discharge sensor 23 changes from the light-transmitting state to the light-blocking state is earlier than the timing at which the trailing edge of the sheet 2 passes the first protruding portion 21a.

[0085] The control unit detects an abnormality occurring during the conveyance of the sheet 2 based on the response and output change of the sheet discharge sensor 23 at a timing different from the predetermined timing.

[0086] When an abnormality occurring during the conveyance of the sheet 2 is detected, the control unit stops the motor M and stops the conveyance unit.

[0087] The following will refer to Figure 7 the detection of conveyance abnormalities of the sheet 2. Figure 7 is a diagram illustrating the detection timing of the sheet discharge sensor 23. Figure 7 The vertical axis in represents the output of the sheet discharge sensor 23. When the sheet discharge sensor 23 is in the light-blocking state, the output is "off", and when the sheet discharge sensor 23 is in the light-transmitting state, the output is "on". Figure 7 The horizontal axis in represents time.

[0088] First, when the sheet 2 is not in the conveyance path 42, the signal from the sheet discharge sensor 23 is "off". When the sheet 2 comes into normal contact with the first indicator 21, the signal from the sheet discharge sensor 23 changes to "on".

[0089] When the sheet 2 is being normally conveyed, the signal from the sheet discharge sensor 23 remains in the "ON" state during the passage of the sheet 2 having a predetermined sheet length. After the trailing edge of the sheet 2 has passed the first indicator 21, the signal from the sheet discharge sensor 23 changes back to "OFF". The control unit determines whether the timing at which the output (signal) of the sheet discharge sensor 23 changes from "ON" to "OFF" is within a predetermined trailing edge detection area. When the timing at which the signal changes from "ON" to "OFF" is within the trailing edge detection area, the control unit determines that the sheet 2 is being normally conveyed. The conveyance of the sheet 2 continues. On the other hand, when the timing at which the signal changes from "ON" to "OFF" is outside the trailing edge detection area, the control unit determines that the sheet 2 is being abnormally conveyed, and the control unit stops the motor M and the conveyance unit to stop the conveyance of the sheet 2.

[0090] When the sheet 2 is being normally conveyed, the trailing edge detection area is determined based on the timing at which the trailing edge of the sheet 2 separates from the first protrusion 21a of the first indicator 21, the timing at which the first indicator 21 moves to the first protrusion position, and the timing at which the second indicator 22 moves to the second retracted position. The determination of the trailing edge detection area takes into account variations in the sheet length of the sheet 2 and variations during the conveyance of the sheet 2. The control unit obtains the sheet length of the sheet 2 based on information input by the user and based on the output of a sensor that detects the size of the sheet 2, and the control unit sets the trailing edge detection area based on the sheet length of the sheet 2. The control unit calculates the trailing edge detection area based on the sheet length of the sheet 2. The control unit may set the trailing edge detection area by referring to trailing edge detection area information stored in the storage device of the image forming apparatus 100. When the timing at which the signal changes from "ON" to "OFF" is after the trailing edge detection area, the control unit also stops the conveyance of the sheet 2.

[0091] The case where the sheet 2 is not being normally conveyed will be described below. Specifically, the case where the sheet 2 gets stuck downstream of the first indicator 21 after the sheet 2 has come into contact with the first indicator 21 and the signal from the sheet discharge sensor 23 has changed to "ON" will be described below.

[0092] As described above, when the sheet 2 gets stuck downstream of the first indicator 21, the sheet 2 is folded in a bellows shape. The second protrusion 22a of the second indicator 22 is pushed by the folded sheet 2, and with the first indicator 21 in the first retracted position, the second indicator 22 moves from the second protrusion position to the second retracted position (see Figure 6 ).

[0093] Accordingly, the detection unit 22c shields the sheet discharge sensor 23, and the signal from the sheet discharge sensor 23 changes from "on" to "off". In the case where the second indicator 22 is moved to the second retracted position due to a paper jam of the sheet 2 as described above, the signal from the sheet discharge sensor 23 changes to "off" at a timing earlier than the trailing edge detection area. When the signal from the sheet discharge sensor 23 changes to "off" at a timing earlier than the trailing edge detection area, the control unit determines that the sheet 2 is jammed, and the control unit stops the motor M and stops the conveying unit.

[0094] The foregoing operations are summarized as follows. When the sheet discharge sensor 23 detects the movement of the second indicator 22 before a predetermined time has elapsed after the sheet 2 contacts the first indicator 21 and the sheet discharge sensor 23 detects the movement of the second indicator 22, the control unit stops the conveyance of the sheet 2. The predetermined time refers to the time required for the trailing edge of the sheet 2 to leave the first indicator 21 after the leading edge of the sheet 2 pushes the first indicator 21 when the sheet 2 is normally conveyed in the conveyance path 42. According to the present exemplary embodiment, the end of the predetermined time substantially corresponds to the earlier end in terms of time in the trailing edge detection area.

[0095] As described above, the first indicator 21 and the second indicator 22 are formed as separate components, so that in the case where the sheet 2 is folded in an accordion shape, an abnormal conveyance of the sheet 2 can be detected before the time required for the trailing edge of the sheet 2 to pass the position of the first indicator 21. This enables the image forming apparatus 100 to be stopped promptly. Accordingly, the continuation of the paper jam is prevented, and the difficulty for the user to clear the paper jam is reduced.

[0096] A second exemplary embodiment of the present invention will be described below. Each part similar to the corresponding part according to the first exemplary embodiment is given the same reference numeral as in the first exemplary embodiment, and redundant description thereof will be omitted. The sheet conveying device according to the second exemplary embodiment includes a second indicator 32 having a shape different from that of the second indicator 22 according to the first exemplary embodiment. (Details of the sheet discharge sensor detection structure)

[0097] The following will refer to Figures 8 to 14 describe the structure for detecting the sheet 2.

[0098] Figure 8 is a cross-sectional view illustrating a fixing device 300 according to the present exemplary embodiment. Figure 9 is an exploded perspective view illustrating the first indicator 21, the second indicator (second moving member) 32, and the sheet discharge sensor 23. Figure 10 is a perspective view illustrating a state in which the first indicator 21, the second indicator 32, and the sheet discharge sensor 23 are assembled together.

[0099] In addition to the second indicator 22 according to the first exemplary embodiment, the second indicator 32 according to the present exemplary embodiment further includes a third protrusion 32e. Specifically, the second indicator 32 includes a second protrusion 32a, an adjustable portion 32b, a detected portion 32c, a hole 32d, and a third protrusion 32e. The functions and structures of the second protrusion 32a, the adjustable portion 32b, the detected portion 32c, and the hole 32d of the second indicator 32 are similar to those of the second protrusion 22a, the adjustable portion 22b, the detected portion 22c, and the hole 22d of the second indicator 22 according to the first exemplary embodiment.

[0100] Similar to the second indicator 22 according to the first exemplary embodiment, the second indicator 32 is attached to the first indicator 21.

[0101] The second indicator 32 includes a third protrusion 32e. The third protrusion 32e protrudes into the re-feed path 43 and contacts the sheet 2 conveyed through the re-feed path 43. As Figure 8 shown, in a state where the first indicator 21 and the second indicator 32 are not in contact with the sheet 2, the first indicator 21 is in a first protruding position and the second indicator 32 is in a second retracted position. In this state, the third protrusion 32e is in a third protruding position protruding into the re-feed path 43.

[0102] The movement of the sheet 2 with respect to the first indicator 21 and the second indicator 32 will be described below with reference to Figure 11 The movement of the sheet 2 with respect to the first indicator 21 and the second indicator 32 will be described below with reference to Figure 11 FIG. is a cross-sectional view of the fixing device 300 in a state where the first indicator 21 is moved by the sheet 2.

[0103] As in the first exemplary embodiment, the sheet 2 contacts the first protrusion 21a of the first indicator 21, moves the first indicator 21 from the first protruding position to the first retracted position, and moves the second indicator 32 from the second retracted position to the second protruding position. Accordingly, the detected portion 32c that shields the sheet discharge sensor 23 is moved. In this way, the sheet discharge sensor 23 becomes a light-transmitting state, and the output of the sheet discharge sensor 23 becomes "ON". At the same time, the third protrusion 32e retracts from the third protruding position.

[0104] The behavior of the first indicator 21 and the second indicator 32 in double-sided printing in which images are printed on both sides of the sheet 2 will be described below with reference to Figure 12 The behavior of the first indicator 21 and the second indicator 32 in double-sided printing in which images are printed on both sides of the sheet 2 will be described below with reference to Figure 12 FIG. is a cross-sectional view of the fixing device 300 in a state where the second indicator 32 is moved by the sheet 2 passing through the re-feed path 43.

[0105] As in the first exemplary embodiment, when the sheet 2 is being normally conveyed in the conveyance path 42, the trailing edge of the sheet 2 moves downstream of the first indicator 21 and away from the first indicator 21. Thus, as Figure 8 shown, the first indicator 21 is moved to the first protruding position by the pressing force of the indicator holding spring 25. When the first indicator 21 moves to the first protruding position, the second indicator 32 moves from the second protruding position to the second retracted position. The third protrusion 32e moves to the third protruding position.

[0106] When the second indicator 32 moves to the second retracted position, the detected portion 32c shields the sheet discharge sensor 23. In this way, the sheet discharge sensor 23 becomes in a light-shielded state, and the output of the sheet discharge sensor 23 becomes "off".

[0107] The re-conveyance path 43 is disposed above the conveyance path 42. After the trailing edge of the sheet 2 has left the first indicator 21, the trailing edge of the sheet 2 is lifted from the conveyance path 42 toward the re-conveyance path 43 due to the stiffness of the sheet 2.

[0108] From the point when the output of the sheet discharge sensor 23 becomes "off", the control unit reverses the discharge roller 15. The reversed discharge roller 15 conveys the sheet 2 to the re-conveyance path 43 and brings the sheet into contact with the third protrusion 32e. The sheet 2 pushes the third protrusion 32e, and the second indicator 32 moves from the second retracted position to the second protruding position. At this time, the regulating portion 32b of the second indicator 32 pushes the rotation stopper 21b, and the first indicator 21 moves integrally with the second indicator 32. When the second indicator 32 moves, the detected portion 32c retracts from the sheet discharge sensor 23. In this way, the sheet discharge sensor 23 becomes in a light-transmissive state, and the output of the sheet discharge sensor 23 becomes "on".

[0109] The control unit determines whether the sheet 2 has been normally conveyed to the re-conveyance path 43 based on the timing when the output of the sheet discharge sensor 23 becomes "on".

[0110] The behavior in the case of paper jam occurring after the leading edge of the sheet 2 has passed through the first indicator 21 will be described below with reference to Figure 13 FIG. which shows a cross-sectional view of the fixing device 200 in a state where the sheet 2 is jammed in the conveyance path 42. Figure 13 FIG. is a cross-sectional view showing the fixing device 200 in a state where the sheet 2 is jammed in the conveyance path 42.

[0111] According to this exemplary embodiment, as in the first exemplary embodiment, the folded sheet 2 pushes the second protrusion 32a of the second indicator 32. Since the first indicator 21 is in contact with the sheet 2, the movement from the first retracted position to the first protruding position is restricted. However, since the second indicator 32 is movable relative to the first indicator 21, the second indicator 32 can move from the second protruding position to the second retracted position while the first indicator 21 is in the first retracted position. Thus, the detected portion 32c of the second indicator 32 shields the sheet discharge sensor 23. In this way, the sheet discharge sensor 23 becomes in a light-shielded state, and the output of the sheet discharge sensor 23 becomes "off".

[0112] The detection of conveyance abnormality of the sheet 2 will be described below with reference to Figure 14 FIG. Figure 14 is a diagram illustrating the detection timing of the sheet discharge sensor 23. Figure 14 In FIG., the vertical axis represents the output of the sheet discharge sensor 23. When the sheet discharge sensor 23 is in the light-shielded state, the output is "off", while when the sheet discharge sensor 23 is in the light-transmitting state, the output is "on". Figure 14 In FIG., the horizontal axis represents time.

[0113] As in the first exemplary embodiment, when the sheet 2 is not in the conveyance path 42, the signal from the sheet discharge sensor 23 is "off". When the sheet 2 is in normal contact with the first indicator 21, the signal from the sheet discharge sensor 23 becomes "on".

[0114] When the sheet 2 is being conveyed normally, the state where the signal from the sheet discharge sensor 23 is "on" continues during the passage of the sheet 2 having a predetermined sheet length. After the trailing edge of the sheet 2 passes the first indicator 21, the signal from the sheet discharge sensor 23 changes back to "off". As in the first exemplary embodiment, the control unit determines whether to stop the conveyance of the sheet 2 (the drive of the conveyance unit by the motor M) based on whether the timing at which the signal from the sheet discharge sensor 23 changes from "on" to "off" is a predetermined timing.

[0115] The output of the sheet discharge sensor 23 in single-sided printing in which an image is printed on one side of the sheet 2 is similar to the description according to the first exemplary embodiment, and thus redundant description thereof will be omitted.

[0116] In double-sided printing in which images are printed on both sides of the sheet 2, after the trailing edge of the sheet 2 has left the first indicator 21, the output of the sheet discharge sensor 23 becomes "off". Then, the sheet 2 is conveyed to the re-conveying path 43 by the reversed discharge roller 15. Accordingly, the sheet 2 comes into contact with the third protruding portion 32e of the second indicator 32, and the second indicator 32 moves from the second retracted position to the second protruding position. The output of the sheet discharge sensor 23 becomes "on" again.

[0117] When the timing at which the output of the sheet discharge sensor 23 becomes "on" again is within the predetermined leading edge detection area (reversal), the control unit determines that the sheet 2 is being conveyed normally, and the control unit continues to convey the sheet 2. On the other hand, when the timing at which the output of the sheet discharge sensor 23 becomes "on" again is not within the predetermined leading edge detection area (reversal), the control unit stops the motor M and stops the conveying unit.

[0118] When the sheet 2 is conveyed through the re-conveying path 43, the sheet 2 leaves the third protruding portion 32e. Then, the first indicator 21 moves to the first protruding position, and the second indicator 32 moves to the second retracted position. Accordingly, the detection portion 32c shields the sheet discharge sensor 23. In this way, the sheet discharge sensor 23 becomes a light-shielded state, and the output of the sheet discharge sensor 23 becomes "off".

[0119] When the timing at which the output of the sheet discharge sensor 23 becomes "off" is within the predetermined trailing edge detection area (reversal), the control unit determines that the sheet 2 is being conveyed normally, and the control unit continues to convey the sheet 2. On the other hand, when the timing at which the output of the sheet discharge sensor 23 becomes "off" is not within the predetermined trailing edge detection area (reversal), the control unit stops the motor M and stops the conveying unit. The trailing edge detection area (reversal) is set based on the sheet length of the sheet 2.

[0120] As in the first exemplary embodiment, in the case where the sheet 2 is not conveyed normally, the signal from the sheet discharge sensor 23 becoming "off" at a timing earlier than the trailing edge detection area of the sheet 2 causes paper jamming. When the signal from the sheet discharge sensor 23 becomes "off" at a timing earlier than the trailing edge detection area, the control unit determines that the sheet 2 is jammed, and the control unit stops the motor M and stops the conveying unit.

[0121] Since the first indicator 21 and the second indicator 32 are separate components, in the case where the sheet 2 is accordion-folded, the sheet conveying device according to the present exemplary embodiment detects an abnormal conveyance of the sheet 2 before the time required for the trailing edge of the sheet 2 to pass the position of the first indicator 21. The sheet conveying device according to the present exemplary embodiment detects an abnormal conveyance of the sheet 2 in the re-conveying path 43. Accordingly, the image forming apparatus 100 quickly stops. This prevents continuous paper jams and reduces the difficulty for the user to clear the paper jam. Since the case where the sheet 2 is jammed in the conveying path 42 or the re-conveying path 43 can be detected by a single second indicator 32, compared with the case where indicators and sensors are separately provided, the space and cost for arranging parts are reduced.

[0122] The sheet discharge sensor 23 and the second indicator 22 or 32 may be arranged such that the sheet discharge sensor 23 is in a light-transmitting state when the second indicator 22 or 32 is in the second retracted position and the sheet discharge sensor 23 is in a light-blocking state when the second indicator 22 or 32 is in the second protruding position.

[0123] Although an image is formed on the sheet 2 via the intermediate transfer belt 11 according to the present exemplary embodiment, the present invention is also applicable to a configuration in which the sheet 2 contacts the photosensitive drum 7 to form an image on the sheet 2.

[0124] Although, as an example of the image forming apparatus according to the present exemplary embodiment, an image forming apparatus capable of attaching and detaching four process cartridges has been described, the present invention is also applicable to an image forming apparatus capable of attaching and detaching a single process cartridge. The present invention is also applicable to a configuration in which a portion corresponding to the process cartridge according to the present exemplary embodiment is fixed to the image forming apparatus. Even in such a case, the present invention is applicable to a configuration in which the sheet 2 contacts the photosensitive drum 7 to form an image on the sheet 2.

[0125] The present invention provides a sheet conveying device capable of detecting a paper jam of a sheet as a recording material at an earlier time point.

[0126] Although the present invention has been described with reference to the exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications as well as equivalent structures and functions.

Claims

1. A sheet conveying device, the sheet conveying device comprising: A conveying unit configured to convey a sheet through a conveying path; A first moving member including a first protrusion, the first moving member being movable between a first protruding position where the first protrusion protrudes into the conveying path and a first retracted position where the first protrusion retracts from the first protruding position, and the first moving member being configured to move from the first protruding position to the first retracted position when the first protrusion contacts the sheet; A second moving member including a second protrusion, the second moving member being configured to move relative to the first moving member, the second moving member being movable between a second protruding position where the second protrusion protrudes into the conveying path and a second retracted position where the second protrusion retracts from the second protruding position, and the second moving member being configured to move from the second retracted position to the second protruding position when the first moving member moves from the first protruding position to the first retracted position; And A detection unit configured to detect the movement of the second moving member, wherein, when the second protrusion is pushed by the sheet, the second moving member moves from the second protruding position to the second retracted position while the first moving member is in the first retracted position.

2. The sheet conveying device according to claim 1, wherein, The first moving member is rotatable about a rotation axis, and the second moving member is rotatable about the rotation axis, and wherein, when viewed from the rotation axis, the rotation direction in which the first moving member moves from the first protruding position to the first retracted position and the rotation direction in which the second moving member moves from the second protruding position to the second retracted position are opposite to each other.

3. The sheet conveying device according to claim 1, wherein, The second protruding position is disposed upstream of the first protrusion along the conveying direction of the sheet in the conveying path.

4. The sheet conveying device according to claim 1, the sheet conveying device further comprising a pressing member configured to press the first moving member and the second moving member, wherein, The first moving member includes a support portion, the second moving member includes a supported portion, and a pressing member presses the first moving member and the second moving member so that the supported portion abuts against the support portion.

5. The sheet conveying device according to claim 4, wherein, The pressing member presses the first moving member and the second moving member such that the first moving member moves from the first protruding position to the first retracted position while the support portion and the supported portion are in contact with each other.

6. The sheet conveying device according to claim 4, wherein, When the second moving member moves from the second protruding position to the second retracted position while the first moving member is in the first retracted position, the supported portion separates from the support portion.

7. The sheet conveying device according to claim 1, wherein, When the first moving member moves between the first protruding position and the first retracted position, the output of the detection unit changes, and when the second moving member moves from the second protruding position to the second retracted position while the first moving member is in the first retracted position, the output of the detection unit changes.

8. The sheet conveying device according to claim 1, the sheet conveying device further comprising a re-conveying path configured to guide the sheet upstream of the conveying path after the sheet passes through the conveying path, wherein, The second moving member includes a third protruding portion that protrudes toward the re-conveying path, and the third protruding portion is configured to contact the sheet passing through the re-conveying path.

9. The sheet conveying device according to claim 1, wherein, The second protruding portion is configured to contact the sheet when the sheet is stuck in the conveying path while the second moving member is in the second protruding position.

10. The sheet conveying device according to claim 1, wherein, The second protruding portion is located at a position away from the sheet being normally conveyed in the conveying path while the second moving member is in the second protruding position.

11. The sheet conveying device according to claim 1, the sheet conveying device further comprising a control unit configured to stop the conveyance of the sheet when the detection unit detects the movement of the second moving member after the detection unit detects the contact between the sheet and the first moving member and before a predetermined time has elapsed.

12. The sheet conveying device according to claim 1, wherein, The conveying path is located downstream of the heating unit in the conveying direction of the sheet, and the heating unit is configured to heat the sheet.

13. The sheet conveying device according to claim 1, wherein,The second moving member is attached to the first moving member.

14. An image forming apparatus, the image forming apparatus comprising: The sheet conveying device according to any one of claims 1 to 13; and an image forming unit configured to form an image on a sheet.

Images