Image forming apparatus

Abstract

Provided is an image forming apparatus capable of stably maintaining an open state and a closed state of a shutter both when the shutter is in an open state and when the shutter is in a closed state. An image forming apparatus (1) includes: a fixing device (6) that includes a heating unit (61) and a pressure roller (62) that forms a nip (NP) with the heating unit (61) and fixes a toner image to a sheet (S); a shutter (64) that can be displaced between a closed position covering a part of the heating unit (61) and an open position opening the part of the heating unit (61); and a biasing member (9) that biases the shutter (64) so as to hold the shutter (64) in the closed position when the shutter (64) is in the closed position, and biases the shutter (64) so as to hold the shutter (64) in the open position when the shutter (64) is in the open position.

Description

Technical Field

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

[0002] Conventionally, in an image forming apparatus including a detachable cartridge, a shutter is provided in front of the fixing device having a heating portion in order to prevent a user's hand from coming into contact with the fixing device.

[0003] For example, in the image forming apparatus disclosed in Patent Document 1, there is a link member connected to the shutter and capable of contacting the box, and the structure is such that when the box is assembled, the link member contacts the box and moves, and the shutter opens along with the movement of the link member. In this case, the shutter is urged toward the closing side by an urging spring.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6961471 Summary of the invention

[0007] Problems to be solved by the invention

[0008] As described above, the gate is urged only toward the closing side by the urging spring, and when the gate is in an open state, an urging force toward the closing side also acts on the gate, so the open state of the gate may become unstable.

[0009] Therefore, the present invention provides an image forming apparatus capable of stably maintaining the shutter in the open state and the closed state both when the shutter is in the open state and when the shutter is in the closed state.

[0010] Means for solving problems

[0011] An image forming apparatus that solves the above-mentioned problems has the following features.

[0012] That is, the image forming device comprises: a fixer having a heating portion and a pressurizing portion forming a clamping portion with the heating portion, so that the colorant image is fixed to a sheet; a gate capable of being displaced to a closed position covering a portion of the heating portion and an open position opening a portion of the heating portion; and a force applying member for applying force to keep the gate in the closed position when the gate is in the closed position, and for applying force to keep the gate in the open position when the gate is in the open position.

[0013] Thus, the shutter at the open position can be stably maintained in an open state, and the shutter at the closed position can be stably maintained in a closed state by one urging member.

[0014] Furthermore, a switching mechanism is provided for switching the urging direction of the urging member between a direction for urging so as to hold the shutter at the closed position and a direction for urging so as to hold the shutter at the open position.

[0015] Thus, the shutter in the open position can be stably maintained in an open state, and the shutter in the closed position can be stably maintained in a closed state by the switching mechanism and the urging member.

[0016] The switching mechanism further includes a link connected to the shutter and movable to a first position for displacing the shutter to a closed position and a second position for displacing the shutter to an open position, and the urging member urges the link.

[0017] Thus, the opening and closing operation of the shutter and the holding of the shutter in the closed position and the open position can be performed by a common member.

[0018] Furthermore, the urging member includes a spring for urging the link and a pressing portion connected to the spring and pressing the link.

[0019] Thus, the link can be pressed stably by the pressing portion connected to the spring.

[0020] In addition, the connecting rod has: a first part, which abuts against the pressing part when the connecting rod is in the first position and changes the direction of the force applied by the spring to the direction of the connecting rod going from the second position to the first position; and a second part, which abuts against the pressing part when the connecting rod is in the second position and changes the direction of the force applied by the spring to the direction of the connecting rod going from the first position to the second position.

[0021] Thus, the shutter at the closed position can be stably maintained in a closed state and the shutter at the open position can be stably maintained in an open state by the urging force of one spring.

[0022] In addition, the first portion of the connecting rod is a first inclined surface inclined relative to the moving direction of the connecting rod, and the second portion of the connecting rod is a second inclined surface inclined relative to the moving direction of the connecting rod, and the inclination direction of the first inclined surface is different from the inclination direction of the second inclined surface.

[0023] Thereby, the first portion and the second portion can be easily formed on the link.

[0024] In addition, the spring of the force-applying component applies force to the pressing portion downward, the first inclined surface of the connecting rod has an inclined shape that rises along the moving direction of the connecting rod from the second position to the first position, and the second inclined surface of the connecting rod has an inclined shape that rises along the moving direction of the connecting rod from the first position to the second position.

[0025] Thus, the biasing direction of the spring can be efficiently converted into a direction in which the link moves from the first position to the second position and a direction in which the link moves from the second position to the first position.

[0026] Furthermore, the pressing portion is an arm having a rotation center at one end and a contact portion that contacts the link at the other end.

[0027] Thereby, the link can be pressed smoothly by the pressing portion.

[0028] Furthermore, an operating member that can be operated by a user to displace the link is provided.

[0029] Thereby, the gate can be opened and closed in conjunction with the user's operation.

[0030] Furthermore, the operating member is a cartridge that is attachable to and detachable from the image forming apparatus, and the shutter moves to the open position when the cartridge is attached to the image forming apparatus and moves to the closed position when the cartridge is detached from the image forming apparatus.

[0031] Thus, the shutter can be moved to the open position and the closed position in accordance with the operation of attaching or detaching the cartridge to or from the image forming apparatus.

[0032] In addition, the box has a photosensitive drum that rotates around a drum shaft, and the connecting rod has a contact piece that contacts the drum shaft, a first connecting rod that contacts the force applying member, and a second connecting rod rotatably connected to the first connecting rod and rotatably connected to the contact piece.

[0033] Thus, the movement of the contact piece by the drum shaft is transmitted to the first link via the second link. Therefore, even if the installation position of the cartridge in the image forming apparatus is far from the shutter, the driving force can be efficiently transmitted from the contact piece to the shutter.

[0034] In addition, the drum shaft of the box detached from the image forming device abuts against the contact piece and presses the first connecting rod in the direction from the second position to the first position. Before the first connecting rod, which is moved from the second position to the first position by being pressed by the drum shaft, reaches the first position, the drum shaft and the contact piece are separated. After the drum shaft and the contact piece are separated, the first connecting rod is forced in the direction from the second position to the first position by the force of the force-applying member and reaches the first position.

[0035] Thus, when the first link reaches the first position and the shutter moves to the closed position, the contact piece of the link separates from the box, so the shutter can be stably maintained in the closed position regardless of the position of the box after separation from the contact piece.

[0036] Furthermore, a restriction surface is provided which abuts against the shutter in the closed position to restrict the position of the shutter.

[0037] Thus, when the shutter moves to the closed position, the shutter abuts against the restriction surface and further movement is restricted, so that the shutter can be held in the closed position.

[0038] Furthermore, the link is configured not to move from the first position toward the second position when a force to move the shutter in the closed position toward the open position is applied to the shutter.

[0039] Thus, even if the shutter in the closed position moves toward the open position, the link does not move, and thus it is possible to prevent the subsequent movement of the link from being hindered.

[0040] In addition, the connecting rod includes: a gate connecting rod connected to the gate to move the gate to the open position and the closed position; a connecting rod cam connected to the gate connecting rod and capable of moving to the first position and the second position; and a connecting rod spring that moves along the movement of the connecting rod cam to press the gate connecting rod, and when the connecting rod cam is in the first position, the connecting rod spring abuts against the gate connecting rod to press the gate connecting rod in the direction in which the gate moves to the closed position, and when the connecting rod cam is in the first position, if the gate moves from the closed position to the open position, the connecting rod spring abutting against the gate connecting rod is elastically deformed, and the connecting rod cam maintains a state of being in the first position.

[0041] Thus, when the link cam is in the first position, if the gate in the closed position moves toward the open position, the link spring abutting against the gate link elastically deforms, and the link cam does not move but maintains the state in the first position, thereby preventing the subsequent movement of the link from being hindered.

[0042] In addition, the image forming device has an opening and an opening and closing cover as the operating member that can move to a closed position for closing the opening and an open position for opening the opening, and when the opening and closing cover is in the closed position, the gate moves to the open position, and when the opening and closing cover is in the open position, the gate moves to the closed position.

[0043] Thereby, the shutter can be moved to the open position and the closed position in accordance with the operation of opening and closing the opening and closing cover.

[0044] Effects of the Invention

[0045] According to the present invention, the shutter at the open position can be stably maintained in an open state, and the shutter at the closed position can be stably maintained in a closed state by one urging member. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a central cross-sectional view showing the image forming apparatus.

[0047] Figure 2 It is a perspective view showing the image forming apparatus in a state where the front cover is in an open position.

[0048] Figure 3 is a side cross-sectional view showing the fixing device.

[0049] Figure 4 It is a perspective view showing a heating unit and a pressure roller of a fixing device.

[0050] Figure 5 (a) is a perspective view of the fixing device showing a state where the shutter is in a closed position, and (b) is a perspective view of the fixing device showing a state where the shutter is in an open position.

[0051] Figure 6 (a) is a side view of the fixing device showing a state where the shutter is in a closed position, and (b) is a side view of the fixing device showing a state where the shutter is in an open position.

[0052] Figure 7 (a) is a side sectional view of the fixing device showing a state where the shutter is in a closed position, and (b) is a side sectional view of the fixing device showing a state where the shutter is in an open position.

[0053] Figure 8 (a) is a front view of the right end portion of the fixing device showing a state where the shutter is in a closed position, and (b) is a front view of the right end portion of the fixing device showing a state where the shutter is in an open position.

[0054] Fig. 9 is a perspective view showing a process cartridge.

[0055] Fig.10is a side view showing the process cartridge.

[0056] Fig.11 It is a side view showing the left side surface of the first main body frame.

[0057] Fig.12 It is a side view showing the right side surface of the first main body frame.

[0058] Fig.13 1 is a side view of the link showing a state in which the first protrusion of the abutment piece is located in the middle of the abutment piece track and the second protrusion is located in the front of the abutment piece track.

[0059] Fig.14 1 is a side view of the first main body frame showing a state in which the process cartridge is located at the assembly start position, the first protrusion of the abutment piece is located at the middle of the abutment piece track, and the second protrusion is located at the front of the abutment piece track.

[0060] Fig.15 It is a figure which shows the contact piece.

[0061] Fig.16 It is an enlarged side view showing a state where the drum shaft entering the middle of the cassette rail abuts against the first protrusion of the abutment piece.

[0062] Fig.17 This is a side view of the link showing a state in which the drum shaft is in contact with the contact piece, a rear portion of the first protrusion of the contact piece is located at the rear of the contact piece track, and the second protrusion is located in the middle of the contact piece track.

[0063] Fig.18 It is a side view of the first main body frame showing a state in which the drum shaft is in contact with the contact piece, a rear portion of the first protrusion of the contact piece is located at the rear of the contact piece track, and the second protrusion is located in the middle of the contact piece track.

[0064] Fig.19 It is an enlarged side view showing a state in which the drum shaft is in contact with the contact piece, a rear portion of the first protrusion of the contact piece is located at the rear of the contact piece track, and the second protrusion is located in the middle of the contact piece track.

[0065] Fig. 20 1 is a side view of the link showing a state in which the drum shaft is in contact with the contact piece, the first protrusion of the contact piece is located at the rear of the contact piece track, and the second protrusion is located in the middle of the contact piece track.

[0066] Fig.21 1 is a side view of the first main body frame showing a state in which the drum shaft is in contact with the contact piece, the first protrusion of the contact piece is located at the rear of the contact piece track, and the second protrusion is located in the middle of the contact piece track.

[0067] Fig. 22It is an enlarged side view showing a state in which the drum shaft moves from the middle to the rear of the cartridge rail and the contact piece and the drum shaft are separated.

[0068] Fig.23 The figure shows that the direct-acting link is moved from Fig.19 The position shown is a side view of the state moved rearward.

[0069] Fig.24 The first protrusion of the contact piece is shown from Fig.21 An enlarged side view showing a state in which the position shown is moved rearward.

[0070] Fig.25 It is a side view of the first main body frame showing a state in which the process cartridge reaches the mounting position after the drum shaft is separated from the abutment piece.

[0071] Fig.26 It is an enlarged side view of the first main body frame showing a state in which the drum shaft reaches the middle of the cartridge rail and abuts against the second protrusion of the abutment piece.

[0072] Fig. 27 It is an enlarged side view of the first main body frame showing a state in which the second protrusion of the contact piece that has come into contact with the drum shaft moves from the middle portion of the contact piece track toward the front portion.

[0073] Fig.28 It is a side view of the connecting rod showing a state in which the second protrusion of the contact piece that contacts the drum shaft moves from the middle of the contact piece track toward the front, and the direct-acting connecting rod moves forward, so that the pressing arm climbs from the second pressed surface of the direct-acting connecting rod to the first pressed surface.

[0074] Fig.29 : is an enlarged side view of the first main body frame showing a state in which the first protrusion of the abutment piece moved by the drum shaft is located in the middle of the abutment piece track and the second protrusion is located in the front of the abutment piece track.

[0075] Fig.30 This is a side view of the link showing a state in which the linear motion link moves forward and the pressing arm shifts from the first pressed surface to the third pressed surface of the linear motion link.

[0076] Fig.31 It is an enlarged side view of the first main body frame showing a state in which the contact piece moves until the second protrusion is located in front of the contact piece track and the contact piece and the drum shaft are separated.

[0077] Fig.32 This is a side view of the link showing a state in which the linear motion link moves forward due to the pressing force from the pressing arm until the shutter moves to the closed position.

[0078] Fig.33FIG. 1 shows that the linear link moves forward due to the pressing force from the pressing arm, so that the second protrusion of the contact piece moves from Fig.31 The illustrated position is an enlarged side view of the first main body frame in a state where the position is moved forward along the front portion of the contact piece rail.

[0079] Fig.34 This is a side view showing a state in which the arm of the coil spring elastically deforms and moves upward when the gate link moves toward the gate open position in a state in which the link is in the first position and the gate moves to the closed position.

[0080] Fig.35 It is a side view showing an operation member for moving a link according to a second embodiment. DETAILED DESCRIPTION

[0081] Next, a mode for carrying out the present invention will be described using the drawings.

[0082] [Image forming apparatus]

[0083] Figure 1 The image forming apparatus 1 shown is one embodiment of an image forming apparatus including a sheet conveying device according to the present invention, and is a laser printer that forms an image on a sheet S by an electrophotographic method.

[0084] In the following description, Figure 1 The right side in FIG. 1 is defined as the front side of the image forming device 1. Figure 1 The left side in the figure is defined as the rear side of the image forming device 1. Figure 1 The front side of the paper in FIG. 1 is defined as the left side of the image forming device 1. Figure 1 The back side of the paper in FIG. 1 is defined as the right side of the image forming device 1. Figure 1 The upper side and the lower side in numeral 1 are respectively defined as the upper side and the lower side of the image forming apparatus 1 .

[0085] The image forming apparatus 1 includes an apparatus main body 2 , a paper feeding unit 3 , an image forming unit 5 , a fixing device 6 , and a paper discharge unit 7 .

[0086] The device body 2 accommodates the paper feed unit 3, the image forming unit 5, the fixing device 6, and the paper discharge unit 7. An opening 2A is opened on the front surface of the device body 2, and the device body 2 has a front cover 21 that can open and close the opening 2A. The front cover 21 is configured to be rotatable around a rotation shaft 21a at the lower end, and can move between a closed position for closing the opening 2A and an open position for opening the opening 2A by rotating around the rotation shaft 21a. The opening 2A is an example of an opening, and the front cover 21 is an example of an operating member operated by a user.

[0087] The paper feed section 3 includes a paper feed tray 10 for supporting a sheet S, a sheet conveying section 30, a conveying roller pair 34, and a registration roller 35a. The paper feed section 3 is disposed at the lower portion of the apparatus body 2, and conveys the sheet S supported by the paper feed tray 10 to the image forming section 5. The image forming apparatus 1 has a conveying path P for the sheet S from the paper feed section 3 via the image forming section 5 to the paper discharge section 7.

[0088] The paper feed tray 10 has a pressure plate 12 and a pressing plate 13. The pressure plate 12 is a plate-shaped member that supports the sheet S from below. The pressure plate 12 is configured to be rotatable around a rotation fulcrum 12a at the rear end, and can be raised and lowered between a lowered position and an raised position by rotating around the rotation fulcrum 12a. The pressing plate 13 is located below the pressure plate 12, and can raise and lower the pressure plate 12 between a lowered position and an raised position.

[0089] The sheet conveying unit 30 is a conveying mechanism that separates and takes out the sheets S supported on the paper feed tray 10 one by one and conveys the sheets toward the image forming unit 5 , and includes a paper feed roller 31 , a separation roller 32 , and a separation pad 33 .

[0090] The paper feed roller 31 is a roller for feeding the sheet S supported by the paper feed tray 10 toward the separation roller 32. The separation roller 32 is disposed downstream of the paper feed roller 31 in the sheet conveying direction. The separation pad 33 is disposed opposite to the separation roller 32 and is urged toward the separation roller 32.

[0091] The sheet S fed by the paper feed roller 31 toward the separation roller 32 is separated into sheets between the separation roller 32 and the separation pad 33. The separated sheets S are fed into the transport path P one by one.

[0092] The sheet S fed to the transport path P is transported toward the image forming unit 5 by the transport roller pair 34, the registration roller 35a, and the pinch roller 35b disposed opposite to the registration roller 35a. The registration roller 35a restricts the movement of the leading end of the transported sheet S to temporarily stop it, and then transports the sheet S toward the image forming unit 5 at a predetermined timing.

[0093] The image forming section 5 is arranged on the downstream side of the sheet conveying direction of the paper feed section 3, and forms an image on the sheet S conveyed from the paper feed section 3. The image forming section 5 includes a process cartridge 50 for transferring an image on the surface of the sheet S conveyed from the paper feed section 3, a transfer roller 55 arranged opposite to the photosensitive drum 54 of the process cartridge 50, and an exposure unit 56 for exposing the surface of the photosensitive drum 54. The process cartridge 50 is an example of a cartridge that can be attached to and detached from the image forming apparatus, and the cartridge is an example of an operating member operated by a user.

[0094] The process cartridge 50 is disposed above the paper feed unit 3 in the apparatus main body 2, and includes a developer storage chamber 51, a supply roller 52, a developing roller 53, a photosensitive drum 54, etc. The process cartridge 50 supports the pinch roller 35b.

[0095] The process cartridge 50 includes a drum cartridge having a photosensitive drum 54 and a developer cartridge mounted on the drum cartridge and having a developer roller 53, and is detachably mounted on the apparatus main body 2. In this case, the process cartridge 50 is mounted to the apparatus main body 2 by inserting the drum cartridge and the developer cartridge mounted on the drum cartridge into the apparatus main body 2 as a whole, and is detached from the apparatus main body 2 by pulling the drum cartridge and the developer cartridge mounted on the drum cartridge out of the apparatus main body 2 as a whole.

[0096] The process cartridge 50 is an example of a cartridge, and can be configured to include at least one of a photosensitive drum, a developing roller, and a toner container. The process cartridge 50 is attachable to and detachable from the apparatus body 2 when the front cover 21 is in the open position.

[0097] The photosensitive drum 54 is disposed with the axis X along the left-right direction when the process cartridge 50 is mounted in the apparatus body 2. The photosensitive drum 54 has a metal drum shaft 54a extending along the axis X. The photosensitive drum 54 rotates around the drum shaft 54a.

[0098] In the present embodiment, the processing box 50 includes a drum box having a photosensitive drum 54 and a developer box mounted on the drum box and having a developing roller 53, but can also be formed into a structure including a box having the photosensitive drum 54 and the developing roller 53 and a toner box mounted on the box and storing colorant.

[0099] In addition, in the image forming apparatus, a drum cartridge having a photosensitive drum 54 and a developing cartridge having a developing roller 53 can be separately mounted to the apparatus main body 2. That is, the process cartridge 50 can be formed into a structure that includes at least one of a photosensitive drum, a developing roller, and a toner container and is detachably mounted to the apparatus main body.

[0100] The exposure unit 56 includes a laser diode, a polygon mirror, a lens, a reflection mirror, and the like, and irradiates the photosensitive drum 54 with laser light based on image data input to the image forming apparatus 1 , thereby exposing the surface of the photosensitive drum 54 .

[0101] The developer storage chamber 51 stores toner to be a developer. The toner stored in the developer storage chamber 51 is transported to the supply roller 52 while being stirred by a stirring member (not shown). The supply roller 52 further supplies the toner transported from the developer storage chamber 51 to the developing roller 53.

[0102] The developing roller 53 is arranged in close contact with the supply roller 52, and carries the toner supplied from the supply roller 52 and positively charged by a sliding contact member (not shown). A developing bias is applied to the developing roller 53 by a bias applying unit (not shown).

[0103] The photosensitive drum 54 is disposed adjacent to the developing roller 53. The surface of the photosensitive drum 54 is uniformly charged by a charger (not shown) and then exposed by the exposure unit 56. The exposed portion of the photosensitive drum 54 has a lower potential than other portions, and an electrostatic latent image based on image data is formed on the photosensitive drum 54. Then, by supplying positively charged toner from the developing roller 53 to the surface of the photosensitive drum 54 on which the electrostatic latent image is formed, the electrostatic latent image is visualized to become a toner image.

[0104] The transfer roller 55 is arranged opposite to the photosensitive drum 54, and a transfer bias is applied by a bias applying unit (not shown). The sheet S is conveyed while being sandwiched between the photosensitive drum 54 on which the toner image is formed and the transfer roller 55 in a state where the transfer bias is applied to the surface of the transfer roller 55, so that the toner image formed on the surface of the photosensitive drum 54 is transferred to the surface of the sheet S. The sheet S to which the toner image is transferred is conveyed to the fixing device 6.

[0105] The fixing device 6 includes a heating unit 61 and a pressure roller 62, and fixes the image transferred to the sheet S by the process cartridge 50. The heating unit 61 is heated by supplying power from a power source (not shown). The heating unit 61 is an example of a heating unit, and the pressure roller 62 is an example of a pressure unit. The pressure roller 62 is arranged opposite to the heating unit 61. One of the heating unit 61 and the pressure roller 62 is urged relative to the other by an urging mechanism (not shown), so that the heating unit 61 and the pressure roller 62 are in close contact with each other.

[0106] When the sheet S with the toner image transferred thereto is conveyed to the fixing device 6, the sheet S is conveyed while being sandwiched between the heating unit 61 and the pressure roller 62 to heat the sheet S and fix the toner image to the sheet S. Thus, the fixing device 6 fixes the toner image transferred to the conveyed sheet S.

[0107] The paper discharge section 7 is located on the downstream side of the image forming section 5 in the sheet conveying direction, and discharges the sheet S on which the image is formed by the image forming section 5 to the outside of the image forming apparatus 1. The paper discharge section 7 includes a paper discharge roller pair 71 and a paper discharge tray 72. The paper discharge roller pair 71 is configured to discharge the sheet S conveyed from the fixing device 6 along the conveying path P to the outside of the apparatus main body 2. The paper discharge tray 72 is formed on the upper surface of the apparatus main body 2, and supports the sheet S discharged to the outside of the apparatus main body 2 by the paper discharge roller pair 71.

[0108] like Figure 2As shown, the device body 2 includes a first main frame 24 and a second main frame 25 which are arranged to be separated from each other in the left-right direction. The first main frame 24 is located at the right end of the device body 2, and the second main frame 25 is located at the left end of the device body 2. The first main frame 24 extends in the front-to-back direction and the up-down direction, and is arranged with the board surface facing the left-to-right direction. The second main frame 25 extends in the front-to-back direction and the up-down direction, and is arranged with the board surface facing the left-to-right direction.

[0109] The process cartridge 50 and the fixing device 6 are arranged between the first main body frame 24 and the second main body frame 25. The first main body frame 24 is arranged on the right side of the process cartridge 50 and the fixing device 6, and the second main body frame 25 is arranged on the left side of the process cartridge 50 and the fixing device 6. The process cartridge 50 is supported by the first main body frame 24 and the second main body frame 25 in a detachable manner.

[0110] [Fuser]

[0111] like Figure 3 , Figure 4 As shown, the heating unit 61 of the fixing device 6 includes a heater 611, a bracket 612, a stay 613, and a belt 614. The heater 611 is a flat plate heater extending in the left-right direction. The heater 611 has a first surface 611A and a second surface 611B on the opposite side of the first surface 611A, and the first surface 611A is supported by the bracket 612.

[0112] The bracket 612 is made of, for example, a resin member, and has a guide surface 612a and a support wall 612b. The guide surface 612a contacts the inner peripheral surface 614a of the belt 614 to guide the belt 614. The support wall 612b has a support surface 612A that supports the heater 611. The support surface 612A of the support wall 612b abuts against the first surface 611A of the heater 611. The stay 613 is a member that supports the bracket 612, and is formed by bending a plate material, such as a steel plate, that is more rigid than the bracket 612 into a substantially U-shaped cross-sectional view.

[0113] The belt 614 is an endless belt having heat resistance and flexibility, and has a metal tube made of a metal such as stainless steel and a fluororesin layer covering the metal tube. The heater 611, the bracket 612 and the stay 613 are arranged inside the belt 614. The belt 614 is configured to rotate around the heater 611, the bracket 612 and the stay 613. The inner peripheral surface 614a of the belt 614 is in contact with the heater 611.

[0114] The pressure roller 62 has a metal shaft 62A and an elastic layer 62B covering the shaft 62A. The pressure roller 62 is pressed against the heater 611 via the belt 614. The pressure roller 62 forms a nip portion NP for heating and pressurizing the sheet S by sandwiching the belt 614 between the pressure roller 62 and the heater 611. In other words, the pressure roller 62 and the heating unit 61 form a nip portion NP, and the sheet S is heated and pressurized in the nip portion NP together with the heater 611.

[0115] The pressure roller 62 is configured to be rotationally driven by a driving force transmitted from a motor provided in the image forming apparatus 1. The pressure roller 62 is rotationally driven to cause the belt 614 to rotate by friction with the belt 614 or the sheet S held by the nip portion NP. Thus, the sheet S to which the toner image is transferred is transported between the pressure roller 62 and the heated belt 614, and the toner image is thermally fixed to the sheet S.

[0116] like Figure 1 , Figure 5~Figure 7 As shown, the fixing device 6 includes a fixing frame 63 covering the heating member 61 and the pressure roller 62, and a shutter 64 supported by the fixing frame 63. The fixing frame 63 holds the heating member 61 and the pressure roller 62. The fixing frame 63 covers the periphery of the heating member 61 and the pressure roller 62, and includes a first opening 63a formed on the upstream side of the heating member 61 and the pressure roller 62 in the sheet conveying direction, and a second opening 63b formed on the downstream side of the heating member 61 and the pressure roller 62 in the sheet conveying direction. The fixing frame 63 covers the heating unit 61 from above.

[0117] The gate 64 is located on the upstream side of the first opening 63a in the fixing frame 63 in the sheet conveying direction, and has a rotation shaft 641 extending in the left-right direction and a connecting shaft 642 protruding in a direction parallel to the rotation shaft 641. The rotation shaft 641 is rotatably supported by the fixing frame 63. The rotation shaft 641 is provided at the left and right ends of the gate 64, and the connecting shaft 642 protrudes to the right from the right end of the gate 64.

[0118] The shutter 64 is configured to be rotatable about a rotation shaft 641, and can be moved to a closed position (closed position) blocking the first opening 63a by rotating about the rotation shaft 641. Figure 5 (a) Figure 6 (a) Figure 7 The position shown in (a) of FIG. 1 and the open position ( Figure 5 (b) Figure 6 (b) Figure 7When the gate 64 is in the closed position, the clamping portion NP between the heating member 61 and the pressure roller 62 is covered by the gate 64, and when the gate 64 is in the open position, the clamping portion NP between the heating member 61 and the pressure roller 62 is exposed to the outside of the fixing frame 63 through the first opening 63a.

[0119] In addition, the shutter 64 covers a part of the heating member 61 when in the closed position, and opens a part of the heating member 61 when in the open position. In other words, the shutter 64 can be displaced to the closed position covering a part of the heating member 61 and the open position opening a part of the heating member 61.

[0120] like Figure 5 , Figure 7 , Figure 8 As shown, the gate 64 has an abutting end portion 64a located at the upper end when in the closed position. The fixing frame 63 has an abutting surface 631 for the gate 64 in the open position to abut. The abutting surface 631 faces the upstream side in the sheet conveying direction, and when the gate 64 is in the open position, the abutting end portion 64a of the gate 64 abuts against it. The abutting end portion 64a of the gate 64 abuts against the abutting surface 631, thereby restricting the gate 64 from further moving in the opening direction. In other words, the abutting surface 631 is a restricting surface on the open position side that abuts against the gate 64 in the open position to restrict the position of the gate 64.

[0121] like Figure 5 , Figure 6 , Figure 8 As shown, the shutter 64 has a contact portion 64b that contacts the fixing frame 63 when the shutter 64 is in the closed position. The contact portion 64b is located at the right end of the shutter 64. The fixing frame 63 has a contact surface 632 that contacts the shutter 64 in the closed position.

[0122] The abutting surface 632 faces the upstream side in the sheet conveying direction, and when the gate 64 is in the closed position, the abutting portion 64b of the gate 64 abuts against it. The abutting portion 64b of the gate 64 abuts against the abutting surface 632, thereby restricting the gate 64 from further moving in the closing direction. In other words, the abutting surface 632 is a restricting surface on the closed position side that abuts against the gate 64 in the closed position to restrict the position of the gate 64.

[0123] It should be noted that, in the present embodiment, the fixing device 6 includes a heating unit 61 having a heater 611 and a belt 614 and a pressure roller 62, but the fixing device 6 can also be formed into a structure including a heating roller with a built-in heater and a pressure roller pressed against the heating roller. In addition, the fixing device 6 can also be formed into a structure including a heating roller with a built-in heater and a pressure belt pressed against the heating roller by an elastic member.

[0124] [Drum shaft]

[0125] like Fig. 9 , Fig.10 As shown, the drum shaft 54a of the photosensitive drum 54 protrudes rightward from the right end of the process cartridge 50 along the axis X direction. That is, the drum shaft 54a protrudes toward the first main frame 24 side along the axis X direction.

[0126] [First main frame]

[0127] like Fig.11 , Fig.12 As shown, the first main body frame 24 has a front frame 24A located in the front and a rear frame 24B located behind the front frame 24A. The front frame 24A and the rear frame 24B are integrally formed continuously in the front-rear direction. The front frame 24A of the first main body frame 24 is an example of a frame.

[0128] The front frame 24A of the first main body frame 24 has a box rail 241 and an abutment piece rail 242. The box rail 241 is formed in a groove shape with the left side open. The box rail 241 extends in the front-rear direction and is inclined in a direction that descends as it goes from the front to the rear.

[0129] The drum shaft 54a of the photosensitive drum 54 can enter the cartridge rail 241, and the cartridge rail 241 guides the drum shaft 54a when the process cartridge 50 is assembled to the device body 2 and when the process cartridge 50 is detached from the device body 2. The drum shaft 54a guided by the cartridge rail 241 enters the cartridge rail 241 from the left side. It should be noted that the process cartridge 50 is assembled to the device body 2 from the front toward the rear, and detached from the device body 2 from the rear toward the front.

[0130] In this way, the cartridge rail 241 of the front frame 24A guides the drum shaft 54a when the process cartridge 50 is attached to the apparatus main body 2 and when the process cartridge 50 is detached from the apparatus main body 2. The cartridge rail 241 is an example of a first guide groove that guides the drum shaft.

[0131] The contact piece rail 242 is formed in a groove shape with the right side open. The contact piece rail 242 extends in the front-to-back direction and is inclined in a direction that decreases as it goes from the front to the rear. The contact piece rail 242 is located to the right of the box rail 241 in the left-right direction. In other words, the contact piece rail 242 is located outside the box rail 241 in the left-right direction.

[0132] The box rail 241 has a front portion 241a located in the front, a rear portion 241c located in the rear, and a middle portion 241b located between the front portion 241a and the rear portion 241c. The abutment piece rail 242 has a front portion 242a located in the front, a rear portion 242c located in the rear, and a middle portion 242b located between the front portion 242a and the rear portion 242c.

[0133] The middle portion 241b of the box rail 241 and the middle portion 242b of the contact piece rail 242 overlap and communicate with each other. The middle portion 241b and the middle portion 242b form a through hole 24C that penetrates the front frame 24A in the left-right direction.

[0134] That is, a portion of the box rail 241, namely the middle portion 241b, overlaps with a portion of the contact piece rail 242, namely the middle portion 242b, and the overlapping portion of the box rail 241 and the contact piece rail 242 is the through hole 24C. In this way, by partially overlapping the box rail 241 and the contact piece rail 242, the member forming the box rail 241 and the member forming the contact piece rail 242 can be common.

[0135] In the through hole 24C, the drum shaft 54 ​​a enters the cartridge rail 241 when the process cartridge 50 is assembled to the apparatus main body 2 or when the process cartridge 50 is detached from the apparatus main body 2 .

[0136] The front portion 242 a of the contact piece rail 242 is located above the front portion 241 a of the cassette rail 241 , and the rear portion 242 c of the contact piece rail 242 is located above the rear portion 241 c of the cassette rail 241 .

[0137] [link]

[0138] like Figure 6 , Fig.13 , Fig.14 As shown in FIG. 1 , the device body 2 includes a connecting rod 8 that can abut against the process cartridge 50 and move the shutter 64 to the open position and the closed position. The connecting rod 8 is connected to the shutter 64. When the process cartridge 50 is assembled to the device body 2, the connecting rod 8 abuts against the process cartridge 50 to move the shutter 64 from the closed position to the open position, and when the process cartridge 50 is detached from the device body 2, the connecting rod 8 abuts against the process cartridge 50 to move the shutter 64 from the open position to the closed position. In this way, the connecting rod 8 moves the shutter 64 to the closed position and the open position according to the movement of the process cartridge 50.

[0139] That is, the link 8 is a structure that opens and closes the shutter 64 according to the attachment and detachment of the process cartridge 50 to the apparatus main body 2. Specifically, the shutter 64 moves to the open position when the process cartridge 50 is mounted on the image forming apparatus 1, and moves to the closed position when the process cartridge 50 is detached from the image forming apparatus 1. The link 8 is located on the opposite side of the process cartridge 50 mounted on the apparatus main body 2 with respect to the front frame 24A of the first main body frame 24 in the left-right direction.

[0140] The connecting rod 8 can be moved in a manner such that it is located in the first position before the process cartridge 50 is mounted to the apparatus main body 2. When the connecting rod 8 is in the first position, the shutter 64 moves to the closed position. The connecting rod 8 can be moved in a manner such that it is located in the second position after the process cartridge 50 is mounted to the apparatus main body 2. When the connecting rod 8 is in the second position, the shutter 64 moves to the open position.

[0141] That is, the connecting rod 8 can be displaced to a first position for moving the gate 64 to a closed position and a second position for moving the gate 64 to an open position. When the connecting rod 8 moves the gate 64 from the closed position to the open position, the connecting rod 8 is displaced in a first direction from the first position toward the second position. In addition, when the connecting rod 8 moves the gate 64 from the open position to the closed position, the connecting rod 8 is displaced in a second direction from the second position toward the first position.

[0142] The link 8 includes a contact piece 80, a first rotating link 81, a direct-acting link 82, a second rotating link 83, a third rotating link 84, a gate link 85, and a coil spring 86. The direct-acting link 82 is an example of a first link, and the first rotating link 81 is an example of a second link.

[0143] The contact piece 80 moves by contacting the drum shaft 54a of the photosensitive drum 54. The contact piece 80 is slidably fitted in the contact piece rail 242, and the contact piece rail 242 guides the contact piece 80 that moves by contacting the drum shaft 54a. The contact piece rail 242 is an example of a second guide groove that guides the contact piece.

[0144] like Fig.15 As shown, the contact piece 80 has a main body 801, a connecting portion 802, a first protrusion 803 and a second protrusion 804. The main body 801 is formed of a plate-shaped member with a plate surface facing the left and right directions. The connecting portion 802 is a protrusion protruding from the right surface of the main body 801 toward the right.

[0145] The first protrusion 803 and the second protrusion 804 are protrusions protruding toward the left from the left surface of the main body 801. The first protrusion 803 and the second protrusion 804 enter the contact piece rail 242 of the first main body frame 24 from the right side and are guided by the contact piece rail 242.

[0146] When the first protrusion 803 and the second protrusion 804 enter the contact piece rail 242, the second protrusion 804 is located at the upstream side of the first protrusion 803 in the assembly direction of the process cartridge 50 relative to the device body 2. It should be noted that the assembly direction is the direction in which the process cartridge 50 inserted into the device body 2 moves toward the assembly position when the process cartridge 50 is assembled relative to the device body 2.

[0147] The contact piece 80 is located on the opposite side of the process cartridge 50 mounted on the apparatus body 2 relative to the front frame 24A of the first main frame 24. The first protrusion 803 and the second protrusion 804 are located at a position that does not protrude toward the process cartridge 50 side from the front frame 24A of the first main frame 24 when entering the contact piece rail 242.

[0148] The first protrusion 803 abuts against the drum shaft 54a when the process cartridge 50 is assembled to the apparatus main body 2, and the second protrusion 804 abuts against the drum shaft 54a when the process cartridge 50 is detached from the apparatus main body 2. In other words, the first protrusion 803 abuts against the drum shaft 54a of the process cartridge 50 assembled to the apparatus main body 2, and the second protrusion 804 abuts against the drum shaft 54a of the process cartridge 50 detached from the apparatus main body 2.

[0149] In this case, when the first protrusion 803 is located at the middle portion 242b (through hole 24C) of the contact piece rail 242, it contacts the drum shaft 54a of the process cartridge 50 mounted to the apparatus main body 2 via the through hole 24C. In addition, when the second protrusion 804 is located at the middle portion 242b (through hole 24C) of the contact piece rail 242, it contacts the drum shaft 54a of the process cartridge 50 detached from the apparatus main body 2 via the through hole 24C.

[0150] The drum shaft 54a that abuts against the first protrusion 803 and the second protrusion 804 via the through hole 24C may abut against the first protrusion 803 and the second protrusion 804 inside the through hole 24C, or may abut against the first protrusion 803 and the second protrusion 804 at a position extending to the right of the through hole 24C in the left-right direction.

[0151] It should be noted that in this embodiment, the contact piece 80 is configured to move by contacting the drum shaft 54a, but it is also possible to form a box protrusion protruding toward the first main frame 24 side independently of the processing box 50 and the drum shaft 54a, and configure the contact piece 80 to move by contacting the box protrusion.

[0152] The first rotating link 81 is a substantially linear member rotatably connected to the contact piece 80. The first rotating link 81 is located on the right side of the front frame 24A of the first main body frame 24 in the left-right direction. The first rotating link 81 has a fitting portion 811 located at the front end portion and rotatably fitted with the connecting portion 802 of the contact piece 80, and a protrusion 812 located at the rear end portion and protruding to the left. The first rotating link 81 is arranged in an inclined posture in which the fitting portion 811 is located above and in front of the protrusion 812. The first rotating link 81 is connected to the contact piece 80 by fitting the connecting portion 802 to the fitting portion 811, and rotates along the movement of the contact piece 80.

[0153] The direct-acting link 82 is a substantially linear member that is rotatably connected to the first rotating link 81 and extends in the front-to-back direction. The direct-acting link 82 is located to the right of the front frame 24A of the first main body frame 24 in the left-right direction. The direct-acting link 82 has a fitting portion 821 located at the front end portion and into which the protrusion 812 of the first rotating link 81 is rotatably fitted, and a connecting hole 822 located at the rear end portion. The direct-acting link 82 is connected to the first rotating link 81 by fitting the protrusion 812 to the fitting portion 821, and moves linearly in the front-to-back direction along with the rotation of the first rotating link 81.

[0154] The direct-acting link 82 moves from the front to the rear when the link 8 moves the gate 64 from the closed position to the open position, and moves from the rear to the front when the link 8 moves the gate 64 from the open position to the closed position. The position of the direct-acting link 82 that moves the gate 64 to the closed position is the first position, and the position of the direct-acting link 82 that moves the gate 64 to the open position is the second position. That is, in the present embodiment, the first direction from the first position of the direct-acting link 82 to the second position is the rear direction, and the second direction from the second position of the direct-acting link 82 to the first position is the front direction.

[0155] The second rotating link 83 is connected to the linear link 82 and supported by the first main frame 24. The second rotating link 83 includes a support portion 831 rotatably supported by the first main frame 24, a first arm 832 extending substantially downward from the support portion 831, and a second arm 833 extending substantially upward from the support portion 831. An engaging pin 832a protruding to the left is formed at the top end of the first arm 832, and a connecting hole 833a is formed at the top end of the second arm 833.

[0156] The engagement pin 832a of the first arm 832 enters the connection hole 822 of the linear link 82 from the right, and engages with the connection hole 822 along with the front-rear movement of the linear link 82. The second rotation link 83 is connected to the linear link 82 by the engagement pin 832a and the connection hole 822, and rotates around the support portion 831 along with the movement of the linear link 82.

[0157] The third rotating link 84 is connected to the second rotating link 83 and is rotatably supported by the supporting shaft 65 of the fixing device 6. The third rotating link 84 includes a supporting portion 841 rotatably supported by the supporting shaft 65, an engaging pin 842 protruding to the right from the supporting portion 841, an operating cam 843 formed in a circumferential direction of the supporting portion 841 and having a different phase from the engaging pin 842, and a connecting hole 844 formed in the operating cam 843. The connecting hole 844 penetrates the operating cam 843 in the left-right direction. The third rotating link 84 is an example of a link cam.

[0158] The engaging pin 842 of the third rotating link 84 enters the connecting hole 833a of the second rotating link 83 from the left, and is engaged with the connecting hole 833a along with the rotation of the second rotating link 83. The third rotating link 84 is connected to the second rotating link 83 by engaging the engaging pin 842 with the connecting hole 833a, and rotates around the support shaft 65 along with the rotation of the second rotating link 83.

[0159] like Figure 5 , Figure 6 As shown, the shutter link 85 is connected to the third rotating link 84 and is rotatably supported on the support shaft 65 of the fixing device 6. The shutter link 85 moves along with the movement of the third rotating link 84, so that the shutter 64 of the fixing device 6 moves between the closed position and the open position. The shutter link 85 is located at the right end of the fixing device 6 and has a support portion 851, an arm portion 852, an engaging portion 853 and an engaging pin 854.

[0160] The support portion 851 is rotatably supported by the support shaft 65 protruding to the right from the right end of the fixing frame 63. The arm portion 852 is an arm member extending forward from the support portion 851. The engaging portion 853 is located at the front end of the arm portion 852 and has an oblong engaging hole 853a that is long in the front-to-back direction. The connecting shaft 642 protruding to the right from the right end of the gate 64 engages with the engaging hole 853a. The gate link 85 is connected to the gate 64 by the engaging hole 853a and the connecting shaft 642.

[0161] The gate link 85 can rotate about the support portion 851 in the direction in which the engaging portion 853 moves up and down. When the gate link 85 rotates and the engaging portion 853 moves downward, the gate 64 moves to the closed position (see Figure 5 (a) Figure 6 (a)), when the gate link 85 rotates and the engaging portion 853 moves upward, the gate 64 moves to the open position (refer to Figure 5 (b) Figure 6 That is, the gate link 85 moves the gate 64 to the closed position by rotating downward, and moves the gate 64 to the open position by rotating upward.

[0162] The engagement pin 854 protrudes to the right from the end portion of the arm portion 852 on the side of the support portion 851. The engagement pin 854 of the gate link 85 enters the connection hole 844 of the third rotation link 84 from the left.

[0163] The coil spring 86 is supported by the support portion 841 of the third rotating link 84. The coil spring 86 is an example of a link spring. The coil spring 86 moves along with the movement of the third rotating link 84. The coil spring 86 has an arm portion 861. The arm portion 861 extends from the inner diameter side of the connecting hole 844 toward the outer diameter side and enters the connecting hole 844.

[0164] The wrist portion 861 is located above the engaging pin 854 in the connecting hole 844. The coil spring 86 can rotate along the rotation of the third rotating link 84. The edge of the lower end of the connecting hole 844 in the operating cam 843 of the third rotating link 84 forms an engaging surface 844a. The engaging surface 844a is located below the engaging pin 854. The connecting hole 844 has an inner peripheral surface 844b at the edge on the side opposite to the edge forming the engaging surface 844a in the circumferential direction. The inner peripheral surface 844b is located above the wrist portion 861, and there is a gap between the inner peripheral surface 844b and the wrist portion 861.

[0165] The engagement surface 844a of the connection hole 844 engages with the engagement pin 854 when the third rotation link 84 rotates toward the side where the operation cam 843 moves upward. The arm portion 861 of the coil spring 86 engages with the engagement pin 854 when the third rotation link 84 rotates toward the side where the operation cam 843 moves downward.

[0166] The shutter link 85 is connected to the third rotation link 84 by the engagement pin 854 and the arm portion 861 or the engagement surface 843 a , and moves along with the rotation of the third rotation link 84 to move the shutter 64 between the closed position and the open position.

[0167] Specifically, as the third rotating link 84 rotates toward the side where the operating cam 843 moves downward, the gate link 85 is pressed by the coil spring 86 and rotates downward, and the gate 64 moves toward the closed position. The position of the third rotating link 84 when the gate 64 moves to the closed position by the rotation of the third rotating link 84 is the first position.

[0168] In addition, as the third rotating link 84 rotates toward the side where the operating cam 843 moves upward, the gate link 85 is pressed by the engaging surface 844a of the connecting hole 844 and rotates upward, and the gate 64 moves toward the open position. The position of the third rotating link 84 when the gate 64 moves to the open position by the rotation of the third rotating link 84 is the second position.

[0169] In the image forming device 1, when the processing box 50 is assembled or detached relative to the device body 2, the abutment piece 80 of the connecting rod 8 abuts against the drum shaft 54a and moves along the abutment piece track 242, and the driving force is transmitted to the gate 64 through the connecting rod 8, and the gate 64 moves between the closed position and the open position.

[0170] In the present embodiment, the link 8 is a structure including the contact piece 80, the first rotating link 81, the direct-acting link 82, the second rotating link 83, the third rotating link 84, the gate link 85 and the coil spring 86, but it is not limited to this, and it can also be composed of a single link that is connected to the gate 64 and opens and closes the gate 64 by contacting with the process cartridge 50. In addition, the action of the link 8 is not limited to rotation or sliding, and it is sufficient as long as the gate 64 is opened and closed by an appropriate action according to the insertion and removal of the process cartridge 50.

[0171] [Force member]

[0172] like Fig.13 As shown, the device body 2 includes a biasing member 9. The biasing member 9 presses the link 8 toward the direction in which the gate 64 becomes the open position before the gate 64 moves to the open position during the process in which the link 8 moves the gate 64 from the closed position. When the gate 64 is in the open position, the biasing member 9 biases the link 8 in the first direction in which the link 8 moves from the first position to the second position.

[0173] In addition, the urging member 9 presses the connecting rod 8 in the direction in which the gate 64 becomes the closed position before the gate 64 moves to the closed position during the process in which the connecting rod 8 moves the gate 64 from the open position to the closed position. When the gate 64 is in the closed position, the urging member 9 urges the connecting rod 8 in the direction in which the connecting rod 8 moves from the second position to the first position, that is, the second direction.

[0174] Furthermore, the urging member 9 restricts the movement of the connecting rod 8 that moves the gate 64 to the open position or the closed position by pressing the connecting rod 8. That is, the urging member 9 applies force to keep the gate 64 in the closed position when the gate 64 is in the closed position, and applies force to keep the gate 64 in the open position when the gate 64 is in the open position.

[0175] In this way, since the force-applying component 9 applies force in a manner to keep the gate 64 in the closed position when the gate 64 is in the closed position, and applies force in a manner to keep the gate 64 in the open position when the gate 64 is in the open position, the gate 64 in the open position can be stably maintained in an open state and the gate 64 in the closed position can be stably maintained in a closed state by one force-applying component 9.

[0176] The force-applying member 9 includes a pressing spring 92 and a pressing arm 91 pressed by the pressing spring 92 and abutting against the upper surface 82A of the direct-acting connecting rod 82. The pressing spring 92 is an example of a spring that applies force to the connecting rod, and the pressing arm 91 is an example of a pressing portion that is connected to the spring and presses the connecting rod. The pressing spring 92 presses the top end of the pressing arm 91 toward the upper surface 82A side of the direct-acting connecting rod 82. The upper surface 82A of the direct-acting connecting rod 82 is an example of a pressed surface pressed by the pressing arm. The force-applying member 9 can stably press the direct-acting connecting rod 82 by using the pressing arm 91 connected to the pressing spring 92.

[0177] The pressing arm 91 includes a support portion 911 located at the base end of the pressing arm 91 and rotatably supported by the first main frame 24, a contact portion 912 located at the top end of the pressing arm 91 and abutting against the upper surface 82A of the linear link 82, and an engaging portion 913 for engaging the pressing spring 92. The pressing arm 91 extends in the front-to-back direction, with the support portion 911 located at the front end and the contact portion 912 located at the rear end. The engaging portion 913 is located above the contact portion 912. The contact portion 912 can rotate in the up-down direction with the support portion 911 as the center.

[0178] The support portion 911 is the rotation center of the pressing arm 91. The base end of the pressing arm 91 is an example of one end of the pressing portion in the force applying member, and the top end of the pressing arm 91 is an example of the other end of the pressing portion in the force applying member. Since the pressing arm 91 has the abutment portion 912 at the top end, the pressing arm 91 can smoothly press the linear link 82.

[0179] The pressing spring 92 is supported by the first main frame 24, and its lower end is fitted in the fitting portion 913 of the pressing arm 91. The pressing spring 92 urges the contact portion 912 of the pressing arm 91 toward the lower side, which is the upper surface 82A side of the linear link 82, and the contact portion 912 is pressed toward the upper surface 82A from above.

[0180] The upper surface 82A of the linear link 82 has a link protrusion 823 protruding upward toward the biasing member 9 between the fitting portion 821 and the connection hole 822. The link protrusion 823 is formed in a mountain shape having a first pressed surface 823a, a second pressed surface 823b, and a third pressed surface 823c.

[0181] The third pressed surface 823c is an example of a first portion of the connecting rod, and the second pressed surface 823b is an example of a second portion of the connecting rod. The third pressed surface 823c is a first inclined surface inclined relative to the moving direction of the linear connecting rod 82, and the second pressed surface 823b is a second inclined surface inclined relative to the moving direction of the linear connecting rod 82. The inclination direction of the third pressed surface 823c relative to the moving direction of the linear connecting rod 82 is different from the inclination direction of the second pressed surface 823b relative to the moving direction of the linear connecting rod 82.

[0182] The first pressed surface 823a is located at the vertex part of the mountain shape and extends in the horizontal direction. The second pressed surface 823b is located in front of the first pressed surface 823a and is formed as an inclined surface that rises as it goes to the rear. In other words, the second pressed surface 823b is inclined from the bottom to the top along the rearward direction. In this way, the second pressed surface 823b, which is a second inclined surface, has an inclined shape that rises along the moving direction of the direct-acting connecting rod 82 from the first position to the second position. The rear end of the second pressed surface 823b is connected to the front end of the first pressed surface 823a.

[0183] The third pressed surface 823c is located behind the first pressed surface 823a and is formed as an inclined surface that descends as it goes to the rear. In other words, the third pressed surface 823c is inclined from top to bottom along the rearward direction. In this way, the third pressed surface 823c, which is the first inclined surface, has an inclined shape that rises along the moving direction of the direct-acting connecting rod 82 from the second position to the first position. The front end of the third pressed surface 823c is connected to the rear end of the first pressed surface 823a. The third pressed surface 823c is located on the side opposite to the second pressed surface 823b, sandwiching the first pressed surface 823a in the front-to-back direction.

[0184] The direct-acting link 82 can be located at a position where the contact portion 912 of the pressing arm 91 presses the first pressed surface 823a, a position where the contact portion 912 of the pressing arm 91 presses the second pressed surface 823b, and a position where the contact portion 912 of the pressing arm 91 presses the third pressed surface 823c by moving in the front-rear direction. The third pressed surface 823c abuts against the pressing arm 91 when the direct-acting link 82 is in the first position, and the second pressed surface 823b abuts against the pressing arm 91 when the direct-acting link 82 is in the second position.

[0185] Since the first pressed surface 823a is a surface extending in the horizontal direction, when the pressing arm 91 presses the first pressed surface 823a from above, the pressing force of the pressing arm 91 does not act in either the rearward direction which is the direction for the direct-acting link 82 to move to the second position or the forward direction which is the direction for the direct-acting link 82 to move to the first position.

[0186] Since the second pressed surface 823b is a surface that is inclined from the bottom to the top along the rearward direction, when the pressing arm 91 presses the second pressed surface 823b from the top, the pressing force of the pressing arm 91 acts in the rearward direction that is the direction in which the direct-acting link 82 moves to the second position. When the pressing arm 91 abuts against the second pressed surface 823b, the downward direction, i.e., the force direction of the pressing spring 92, is changed from the second pressed surface 823b to the first direction in which the direct-acting link 82 moves from the first position to the second position. In addition, when the pressing arm 91 presses the second pressed surface 823b from the top, the abutting portion 912 of the pressing arm 91 is locked with the second pressed surface 823b, and the forward movement of the direct-acting link 82 is restricted.

[0187] Since the third pressed surface 823c is a surface that is inclined from the top to the bottom along the rearward direction, when the pressing arm 91 presses the third pressed surface 823c from the top, the pressing force of the pressing arm 91 acts in the forward direction that becomes the direction in which the direct-acting link 82 moves to the first position. When the pressing arm 91 abuts against the third pressed surface 823c, the downward direction, i.e., the force direction of the pressing spring 92, is changed from the third pressed surface 823c to the second direction in which the direct-acting link 82 moves from the second position to the first position. In addition, when the pressing arm 91 presses the third pressed surface 823c from the top, the abutting portion 912 of the pressing arm 91 is locked with the third pressed surface 823c, and the movement of the direct-acting link 82 in the rearward direction is restricted.

[0188] In this way, since the direct-acting link 82 has the second pressed surface 823b and the third pressed surface 823c, the gate 64 in the closed position can be stably maintained in a closed state and the gate 64 in the open position can be stably maintained in an open state by the force of a pressing spring 92.

[0189] Furthermore, since the second pressed surface 823 b and the third pressed surface 823 c are inclined surfaces inclined with respect to the moving direction of the linear motion link 82 , the second pressed surface 823 b and the third pressed surface 823 c can be easily formed on the linear motion link 82 .

[0190] In addition, since the second pressed surface 823b has an inclined shape that rises along the moving direction of the direct-acting link 82 from the first position to the second position, and the third pressed surface 823c has an inclined shape that rises along the moving direction of the direct-acting link 82 from the second position to the first position, the force direction of the pressing spring 92 can be efficiently converted into the direction of the direct-acting link 82 from the first position to the second position and the direction of the direct-acting link 82 from the second position to the first position.

[0191] In addition, since the pressing arm 91 of the force member 9 switches between the state of pressing the second pressed surface 823b and the state of pressing the third pressed surface 823c by the displacement of the direct-acting link 82 in the front-rear direction, the link 8 functions as a switching mechanism for switching the force direction of the force member 9 to the direction of applying force in a manner to keep the gate 64 in the closed position and the direction of applying force in a manner to keep the gate 64 in the open position. Thus, the gate 64 in the open position can be stably maintained in the open state and the gate 64 in the closed position can be stably maintained in the closed state by the link 8 and the force member 9 as the switching mechanism.

[0192] Furthermore, by using the link 8 as a switching mechanism for switching the urging direction of the urging member 9 and the urging member 9 urging the link 8 , the shutter 64 can be opened and closed and held in the closed position and the open position by a common member.

[0193] [Movement of connecting rod]

[0194] Next, the operation of the connecting rod 8 will be described.

[0195] (Actions during process cartridge assembly)

[0196] First, the operation of the link 8 when the process cartridge 50 is mounted in the apparatus main body 2 will be described.

[0197] like Fig.13 , Fig.14 As shown, when the process cartridge 50 is in a state before being assembled to the device main body 2 and the top end 50A of the process cartridge 50 in the insertion direction is inserted into the assembly start position of the device main body 2 ( Fig.14 , the drum shaft 54a is separated forward from the abutment plate 80, and the abutment plate 80 is located at a position spanning the front portion 242a and the middle portion 241b of the abutment plate rail 242.

[0198] Specifically, the contact piece 80 is fitted to the contact piece rail 242 with the first protrusion 803 located at the middle portion 242b (through hole 24C) and the second protrusion 804 located at the front portion 242a of the contact piece rail 242. It should be noted that the insertion direction of the process cartridge 50 is the same as the assembly direction.

[0199] When the contact piece 80 is in Fig.14 When the position shown is Figure 6 As shown in (a), the shutter 64 is in a state where it is moved to the closed position by the connecting rod 8. Thus, when the process cartridge 50 is in a state where it is separated from the apparatus body 2, even if the user inserts his hand into the apparatus body 2 through the opening 2A, the shutter 64 can prevent the user's hand from touching the heating unit 61 of the fixing device 6.

[0200] In addition, when the contact piece 80 is in Fig.14 When the position shown is Fig.13 As shown, the contact portion 912 of the pressing arm 91 contacts the third pressed surface 823c of the direct-acting link 82, and the movement of the direct-acting link 82 in the rearward direction is restricted. Thus, when the gate 64 is moved to the closed position by the connecting rod 8, the direct-acting link 82 is fixed by the force member 9, and the gate 64 will not accidentally move from the closed position to the open position, so that the closed position of the gate 64 can be stably maintained.

[0201] Furthermore, the contact piece rail 242 of the front frame 24A that guides the contact piece 80 is located outside the cartridge rail 241 in the left-right direction, and the first protrusion 803 and the second protrusion 804 of the contact piece 80 are located at positions that do not protrude toward the process cartridge 50 side from the front frame 24A. Therefore, when the process cartridge 50 is separated from the apparatus body 2, the user can be prevented from coming into contact with the contact piece 80, and the link 8 can be prevented from moving and accidentally opening the shutter 64.

[0202] If the process cartridge 50 at the assembly start position is further inserted toward the assembly position, the drum shaft 54a enters the front portion 241a of the cartridge track 241 and moves within the cartridge track 241. Fig.16 As shown, if the drum shaft 54 ​​a moving in the cassette rail 241 enters the middle portion 241 b (through hole 24C), the drum shaft 54 ​​a abuts against the first protrusion 803 of the abutment piece 80 .

[0203] like Figure 17~Figure 19 As shown, the contact piece 80 that comes into contact with the drum shaft 54a moving in the middle portion 241b (through hole 24C) of the cartridge rail 241 is pressed by the drum shaft 54a and moves to the downstream side in the mounting direction of the process cartridge 50.

[0204] A portion of the first protrusion 803 of the contact piece 80 that has moved by contacting the drum shaft 54a moving in the middle portion 241b (through hole 24C) is located at the rear portion 242c of the contact piece track 242, and the other portion is located at the middle portion 242b (through hole 24C) of the contact piece track 242. In addition, the second protrusion 804 is located at the middle portion 242b (through hole 24C) of the contact piece track 242.

[0205] When the contact piece 80 moves, the first rotating link 81 connected to the contact piece 80 moves backward while rotating in a direction with a smaller inclination angle relative to the horizontal direction. When the first rotating link 81 rotates and moves, the direct-acting link 82 connected to the first rotating link 81 moves linearly backward.

[0206] If the linear link 82 moves backward, the connection hole 822 of the linear link 82 engages with the engagement pin 832a of the second rotating link 83, and the second rotating link 83 rotates in the direction in which the engagement pin 832a moves backward. If the second rotating link 83 rotates, the connection hole 833a of the second rotating link 83 engages with the engagement pin 842 of the third rotating link 84, and the third rotating link 84 rotates in the direction in which the engagement pin 842 moves forward.

[0207] In this case, as the direct-acting connecting rod 82 moves backward, the contact portion 912 of the pressing arm 91 in the force member 9 gradually rises on the third pressed surface 823c of the direct-acting connecting rod 82 against the pressing force of the pressing spring 92, and climbs up the first pressed surface 823a from the third pressed surface 823c. That is, when the process cartridge 50 is assembled to the device body 2, the pressing arm 91 contacts the third pressed surface 823c and then contacts the first pressed surface 823a. In the state where the pressing arm 91 contacts the first pressed surface 823a, which is a surface extending in the horizontal direction, the restriction on the movement of the shutter 64 from the closed position to the open position side by the force member 9 is released.

[0208] Thus, when the process cartridge 50 is assembled to the apparatus body 2, the direct acting link 82 moves in the first direction, i.e., rearward, against the pressing force from the pressing arm 91, and the shutter 64 can be switched from being held in the closed position to being movable to the open position.

[0209] like Fig. 20 , Fig.21 As shown, if the processing box 50 is removed from Fig.18 If the position shown in the figure is further inserted toward the assembly position, the contact piece 80 is further moved to the downstream side of the assembly direction by the drum shaft 54a moving in the middle portion 241b (through hole 24C) of the cassette rail 241. Fig.21 In the embodiment, the first protrusion 803 of the contact piece 80 is located at the rear portion 242c of the contact piece rail 242, and the second protrusion 804 is located at the middle portion 242b (through hole 24C) of the contact piece rail 242.

[0210] like Fig. 22 As shown, the drum shaft 54a moves from the middle portion 241b of the box rail 241 to the rear portion 241c by moving the contact piece 80 until the first protrusion 803 is located at the rear portion 242c of the contact piece rail 242, and the contact piece 80 and the drum shaft 54a are separated.

[0211] If the contact piece 80 moves, the first rotating link 81 further rotates in a direction in which the inclination angle with respect to the horizontal direction becomes smaller while moving backward. If the first rotating link 81 rotates and moves, the direct-acting link 82 further moves linearly backward. If the direct-acting link 82 moves, the second rotating link 83 further rotates in a direction in which the engaging pin 832a moves backward. If the second rotating link 83 rotates, the third rotating link 84 further rotates in a direction in which the engaging pin 842 moves forward.

[0212] When the third rotating link 84 rotates, the engaging surface 844a of the connecting hole 844 in the operating cam 843 engages from below with the engaging pin 854 of the gate link 85. The engaging surface 844a of the connecting hole 844 engages with the engaging pin 854, and the gate link 85 rotates in the direction in which the engaging portion 853 moves upward, and the gate 64 moves from the closed position to the open position.

[0213] In this case, the movement of the abutment piece 80 achieved by the drum shaft 54a is transmitted to the direct-acting link 82 via the first rotating link 81. Therefore, even if the assembly position of the processing box 50 in the device body 2 is far away from the gate 64, the driving force can be efficiently transmitted from the abutment piece 80 to the gate 64.

[0214] If the abutment piece 80 is moved by the drum shaft 54a to the rear part 242c where the first protrusion 803 is located at the abutment piece rail 242 and the direct-acting link 82 moves rearward, the abutment part 912 of the pressing arm 91 in the force-applying member 9 is transferred from the first pressed surface 823a to the second pressed surface 823b of the direct-acting link 82 by the pressing force of the pressing spring 92.

[0215] When the abutment piece 80 moves through the drum shaft 54a to the point where the first protrusion 803 is located at the rear portion 242c of the abutment piece rail 242, the abutment position of the abutment portion 912 in the pressing arm 91 relative to the second pressed surface 823b changes due to the dimensional tolerances of the components constituting the connecting rod 8 and the tolerances of the connection positions of the components.

[0216] In this case, the positional relationship between the pressing arm 91 and the connecting rod 8 is set in such a manner that the contact portion 912 of the pressing arm 91 is necessarily in contact with the second pressed surface 823b when the contact piece 80 is moved by the drum shaft 54a to the point where the first protrusion 803 is located at the rear portion 242c of the contact piece rail 242. In addition, it is set so that, within the range of tolerance of the components constituting the connecting rod 8, even if the contact portion 912 of the pressing arm 91 is in contact with the lowermost side of the second pressed surface 823b, the contact portion 912 does not contact the upper surface 82A located forward of the second pressed surface 823b.

[0217] After the contact piece 80 moves to the point where the first protrusion 803 is located at the rear portion 242c of the contact piece track 242 and the contact portion 912 contacts the second pressed surface 823b, the first protrusion 803 and the drum shaft 54a are separated, so the drum shaft 54a does not move the contact piece 80. Fig.23 As shown, since the contact portion 912 of the pressing arm 91 contacts the second pressed surface 823 b , a pressing force in the direction of the second position is applied from the pressing arm 91 to the linear motion link 82 , and the linear motion link 82 moves rearward.

[0218] like Figure 6 As shown in (b) of FIG. 1 , when the linear motion link 82 moves rearward due to the pressing force from the pressing arm 91 , the gate link 85 rotates in the direction in which the engaging portion 853 moves upward, and the gate 64 moves to the open position.

[0219] In this case, it is set that when the direct-acting link 82 moves backward by the pressing force from the pressing arm 91 until the gate 64 moves to the open position, the contact portion 912 of the pressing arm 91 does not contact the upper surface 82A located forward of the second pressed surface 823b (see Fig.23 ). Thus, the shutter 64 can be held in the open position by the pressing force from the pressing arm 91.

[0220] In addition, if Fig.24 As shown in FIG. 1 , if the direct-acting link 82 is moved backward by the pressing force from the pressing arm 91, the contact piece 80 is pulled backward by the first rotating link 81, and the first protrusion 803 of the contact piece 80 is moved backward from Fig. 22 The position shown is moved rearwardly along the rear portion 241 c of the abutment plate track 242 .

[0221] When the shutter 64 moves to the open position, the contact end 64a contacts the contact surface 631 of the fixing frame 63, and further movement is restricted, and the movement of the connecting rod 8 also stops. Since the shutter 64 contacts the contact surface 631 to restrict further movement, the shutter 64 can be held in the open position. In addition, since the movement of the connecting rod 8 also stops, the movement range of the connecting rod 8 can be suppressed to be small.

[0222] In addition, when the pressing arm 91 is in contact with the second pressed surface 823b, the contact portion 912 of the pressing arm 91 is locked with the second pressed surface 823b, and the forward movement of the direct-acting link 82 is restricted. Thus, when the gate 64 moves to the open position, the position of the direct-acting link 82 is fixed by the force member 9, and the gate 64 can be prevented from accidentally moving from the open position to the closed position.

[0223] Thus, in the image forming apparatus 1, the structure is as follows: if the drum shaft 54a of the processing box 50 assembled to the apparatus main body 2 and the contact piece 80 of the connecting rod 8 abut against each other and the drum shaft 54a moves the contact piece 80, the gate 64 moves from the closed position toward the open position, and the contact piece 80 and the drum shaft 54a are separated before the gate 64 moves to the open position, and the contact piece 80 separated from the drum shaft 54a further moves toward the direction in which the gate 64 becomes the open position.

[0224] In such a structure, when the shutter 64 moves to the open position, the connecting rod 8 having the contact piece 80 and the processing box 50 having the drum shaft 54a are separated, so the user's operation of the processing box 50 does not affect the opening and closing state of the shutter 64. In addition, after the shutter 64 moves to the open position, there is no need to move the connecting rod 8 further, and the movement range of the connecting rod 8 can be suppressed to be small.

[0225] When the process cartridge 50 is mounted in the apparatus main body 2 , after the process cartridge 50 and the link 8 come into contact, if the link 8 and the process cartridge 50 separate, the pressing arm 91 of the urging member 9 presses the linear motion link 82 toward the second position.

[0226] Thus, even after the link 8 and the process cartridge 50 are separated, the link 8 is pressed toward the second position by the urging member 9 , and therefore the shutter 64 can be moved to the open position by the pressed link 8 .

[0227] In particular, by pressing the second pressed surface 823 b of the linear motion link 82 with the pressing arm 91 , the link 8 can be moved toward the second position and the shutter 64 can be moved toward the open position.

[0228] In addition, the connecting rod 8 is constructed to move toward the second position in the following manner: if the processing box 50 assembled to the device body 2 and the abutment piece 80 of the connecting rod 8 abut, the pressing arm 91 and the first pressed surface 823a of the connecting rod 8 abut, and before the connecting rod 8 and the processing box 50 are separated, the second pressed surface 823b of the connecting rod 8 abuts against the pressing arm 91.

[0229] Thus, when the link 8 and the process cartridge 50 are separated, the pressing arm 91 abuts against the second pressed surface 823 b , so that even after the link 8 and the process cartridge 50 are separated, the shutter 64 can be moved to the open position by the link 8 .

[0230] If the process box 50 is removed from Fig.21 As the position shown in FIG. 2 is further inserted toward the assembly position, the drum shaft 54a moves from the middle portion 241b of the cartridge rail 241 toward the rear portion 241c and moves in the assembly direction within the rear portion 241c. Fig.25 As shown in the figure, it reaches the mounting position and becomes a state of being mounted on the device main body 2.

[0231] (Action when the process cartridge is detached)

[0232] Next, the operation of the link 8 when the process cartridge 50 in the mounting position is detached from the apparatus main body 2 will be described. When the process cartridge 50 is detached, the link 8 operates in the opposite manner to the operation when the process cartridge 50 is mounted.

[0233] like Fig.25 As shown, when the processing box 50 is in the state of being assembled in the device body 2, the drum shaft 54a is separated from the contact piece 80 to the rear, and the contact piece 80 is located at a position spanning the rear portion 242c and the middle portion 242b of the contact piece track 242. Specifically, the first protrusion 803 of the contact piece 80 is located at the rear portion 242c of the contact piece track 242, and the second protrusion 804 is located at the middle portion 242b (through hole 24C) of the contact piece track 242. When the contact piece 80 is in Fig.25 When the position shown is Figure 6 As shown in (b), the gate 64 is in a state where it is moved to the open position by the connecting rod 8.

[0234] In addition, when the contact piece 80 is in Fig.25 When the position shown is Fig.23 As shown, the contact portion 912 of the pressing arm 91 contacts the second pressed surface 823b of the direct-acting link 82, and the forward movement of the direct-acting link 82 is restricted. Thus, when the gate 64 is moved to the open position by the connecting rod 8, the direct-acting link 82 is urged by the urging member 9, and the gate 64 does not accidentally move from the open position to the closed position, so that the open position of the gate 64 can be stably maintained.

[0235] If in Fig.25 When the process cartridge 50 in the assembly position shown in the figure is disengaged from the device body 2 toward the front, the drum shaft 54a moves toward the downstream side of the disengagement direction in the rear portion 241c of the cartridge rail 241. It should be noted that the disengagement direction is the direction in which the process cartridge 50 pulled out of the assembly body 2 moves toward the outside of the assembly body 2 when the process cartridge 50 is disengaged from the device body 2. Fig.26 As shown, when the drum shaft 54 ​​a moving in the cassette rail 241 reaches the middle portion 241 b (through hole 24C), the drum shaft 54 ​​a comes into contact with the second protrusion 804 of the contact piece 80 .

[0236] like Fig. 27As shown in FIG. 1 , the contact piece 80 that is in contact with the drum shaft 54a is pressed by the drum shaft 54a and moves to the downstream side in the direction of separation of the process cartridge 50. That is, the contact piece 80 moves from the position where the first protrusion 803 is located at the rear portion 242c of the contact piece rail 242 to the position where the first protrusion 803 is located at the middle portion 242b (through hole 24C). In this case, the second protrusion 804 pressed by the drum shaft 54a moves from the middle portion 242b (through hole 24C) of the contact piece rail 242 toward the front portion 242a.

[0237] like Fig.28 As shown in FIG. 1 , if the contact piece 80 moves, the first rotating link 81 moves forward while rotating in a direction with a larger inclination angle relative to the horizontal direction, and the direct-acting link 82 moves forward linearly. In other words, the drum shaft 54a of the process cartridge 50 separated from the image forming apparatus 1 contacts the contact piece 80 and presses the direct-acting link 82 in the direction from the second position to the first position, that is, forward.

[0238] In this case, as the direct-acting connecting rod 82 moves forward, the contact portion 912 of the pressing arm 91 in the force member 9 gradually rises on the second pressed surface 823b of the direct-acting connecting rod 82 against the pressing force of the pressing spring 92, and climbs up the first pressed surface 823a from the second pressed surface 823b. That is, when the processing box 50 is separated from the device body 2, the pressing arm 91 contacts the second pressed surface 823b and then contacts the first pressed surface 823a. In the state where the pressing arm 91 contacts the first pressed surface 823a, which is a surface extending in the horizontal direction, the restriction on the movement of the shutter 64 from the open position to the closed position side by the force member 9 is released.

[0239] In addition, if the linear link 82 moves forward, the connection hole 822 of the linear link 82 engages with the engagement pin 832a of the second rotating link 83, and the second rotating link 83 rotates in the direction in which the engagement pin 832a moves forward. If the second rotating link 83 rotates, the connection hole 833a of the second rotating link 83 engages with the engagement pin 842 of the third rotating link 84, and the third rotating link 84 rotates in the direction in which the engagement pin 842 moves backward.

[0240] like Fig.29 As shown in FIG. 2 , if the process cartridge 50 is further separated from the apparatus body 2 , the contact piece 80 is further moved to the downstream side in the separation direction by the drum shaft 54a moving in the middle portion 241b (through hole 24C) of the cartridge rail 241 . Fig.29 In the embodiment, the first protrusion 803 of the contact piece 80 is located at the middle portion 242 b (through hole 24C) of the contact piece rail 242 , and the second protrusion 804 is located at the front portion 242 a of the contact piece rail 242 .

[0241] If the contact piece 80 moves, the first rotating link 81 further rotates in a direction in which the inclination angle relative to the horizontal direction increases while moving forward. If the first rotating link 81 rotates and moves, the direct-acting link 82 further moves linearly forward. If the direct-acting link 82 moves, the second rotating link 83 further rotates in a direction in which the engaging pin 832a moves forward. If the second rotating link 83 rotates, the third rotating link 84 further rotates in a direction in which the engaging pin 842 moves backward.

[0242] When the third rotating link 84 rotates, the coil spring 86 rotates along with the rotation of the third rotating link 84, and the arm 861 of the coil spring 86 engages from above with the engaging pin 854 of the gate link 85. As the arm 861 engages with the engaging pin 854, the gate link 85 rotates in the direction in which the engaging portion 853 moves downward. As a result, the gate 64 moves from the open position to the closed position side.

[0243] In this case, the movement of the abutment piece 80 achieved by the drum shaft 54a is transmitted to the direct-acting link 82 via the first rotating link 81. Therefore, even if the assembly position of the processing box 50 in the device body 2 is far away from the gate 64, the driving force can be efficiently transmitted from the abutment piece 80 to the gate 64.

[0244] like Fig.29 As shown in FIG. 1 , if the contact piece 80 is moved by the drum shaft 54a until the second protrusion 804 is located at the front portion 242a of the contact piece rail 242 and the direct-acting link 82 moves forward, then Fig.30 As shown, the contact portion 912 of the pressing arm 91 in the urging member 9 is transferred from the first pressed surface 823 a to the third pressed surface 823 c of the linear motion link 82 by the pressing force of the pressing spring 92 .

[0245] In this case, the positional relationship between the pressing arm 91 and the connecting rod 8 is set in such a manner that the contact portion 912 of the pressing arm 91 is necessarily in contact with the third pressed surface 823c when the contact piece 80 is moved by the drum shaft 54a to the point where the second protrusion 804 is located at the front portion 242a of the contact piece rail 242. In addition, it is set so that, within the range of tolerance of the components constituting the connecting rod 8, even if the contact portion 912 of the pressing arm 91 is in contact with the lowermost side of the third pressed surface 823c, the contact portion 912 does not contact the upper surface 82A located further back than the third pressed surface 823c.

[0246] like Fig.31As shown, after the abutment piece 80 moves to the point where the second protrusion 804 is located at the front portion 242a of the abutment piece rail 242 and the abutment portion 912 abuts against the third pressed surface 823c, the drum shaft 54a that makes the abutment piece 80 move to the point where the second protrusion 804 is located at the front portion 242a of the abutment piece rail 242 moves from the middle portion 241b of the box rail 241 toward the front portion 241a, and the abutment piece 80 and the drum shaft 54a are separated.

[0247] In addition, when the contact piece 80 and the drum shaft 54a separate, the shutter 64 has not yet reached the closed position. In other words, the drum shaft 54a and the contact piece 80 separate before the direct-acting link 82, which is pressed by the drum shaft 54a and moves from the second position to the first position, reaches the first position.

[0248] After the contact piece 80 moves to the point where the second protrusion 804 is located at the front portion 242a of the contact piece rail 242 and the contact portion 912 contacts the third pressed surface 823c, the second protrusion 804 and the drum shaft 54a separate, so the drum shaft 54a does not move the contact piece 80.

[0249] However, if Fig.30 As shown in FIG. 1 , since the contact portion 912 of the pressing arm 91 contacts the third pressed surface 823c, a pressing force in the direction of the first position is applied from the pressing arm 91 to the direct-acting link 82, and the direct-acting link 82 moves forward. In other words, after the drum shaft 54a and the contact piece 80 are separated, the direct-acting link 82 is urged in the direction of the first position from the second position by the urging force of the urging member 9, thereby reaching the first position.

[0250] like Figure 6 As shown in (a) of FIG. 8 , when the linear link 82 moves forward by the pressing force from the pressing arm 91 and reaches the first position, the shutter link 85 rotates in the direction in which the engaging portion 853 moves downward, and the shutter 64 moves to the closed position.

[0251] In this way, when the direct-acting connecting rod 82 reaches the first position and the gate 64 moves to the closed position, the abutment piece 80 of the connecting rod 8 is separated from the processing box 50. Therefore, no matter what the position of the processing box 50 is after separation from the abutment piece 80, the gate 64 can be stably maintained in the closed position.

[0252] In addition, if Fig.32 As shown, it is set so that: when the direct-acting link 82 moves forward by the pressing force from the pressing arm 91 until the gate 64 moves to the closed position, the abutment portion 912 of the pressing arm 91 does not contact the upper surface 82A located behind the third pressed surface 823c. Thus, the gate 64 can be kept in the closed position by the pressing force from the pressing arm 91.

[0253] In addition, if Fig.33As shown in FIG. 1 , if the direct-acting link 82 is moved forward by the pressing force from the pressing arm 91, the contact piece 80 is pushed forward by the first rotating link 81, and the second protrusion 804 of the contact piece 80 is moved from Fig.31 The position shown is moved forward along the front portion 242 a of the abutment piece rail 242 .

[0254] When the shutter 64 moves to the closed position, the contact portion 64 b contacts the contact surface 632 of the fixing frame 63 , and further movement is restricted, so that the shutter 64 can be held in the closed position.

[0255] In this way, when the process cartridge 50 mounted on the apparatus main body 2 is separated from the apparatus main body 2, the contact piece 80 of the connecting rod 8 contacts the drum shaft 54a of the process cartridge 50, and the connecting rod 8 moves in the direction that the shutter 64 in the open position moves to the closed position. Therefore, the shutter 64 can be moved to the closed position along with the action of separating the process cartridge 50 from the apparatus main body 2.

[0256] As described above, in the image forming device 1, when the processing box 50 is assembled to the device body 2, the drum shaft 54a abuts against the first protrusion 803 of the abutment piece 80, causing the connecting rod 8 to move in the direction of the gate 64 from the closed position to the open position. When the processing box 50 is detached from the device body 2, the drum shaft 54a abuts against the second protrusion 804 of the abutment piece 80, causing the connecting rod 8 to move in the direction of the gate 64 from the open position to the closed position.

[0257] That is, in the image forming apparatus 1, the shutter 64 moves to the open position when the process cartridge 50 is mounted on the image forming apparatus 1, and moves to the closed position when the process cartridge 50 is detached from the image forming apparatus 1. With such a structure, the shutter 64 can be moved to the open position and the closed position in accordance with the operation of attaching and detaching the process cartridge 50 to and from the image forming apparatus 1. In addition, the connecting rod 8 can be operated with a simple structure both when the process cartridge 50 is mounted and detached.

[0258] In addition, in the image forming apparatus 1 , since the link 8 is displaced by the process cartridge 50 , which is an operation member operated by the user, the shutter 64 can be opened and closed in conjunction with the user's operation.

[0259] [Operation when a force is applied to the gate in the closed position to move it to the open position]

[0260] like Figure 6 As shown in (a), when the link 8 is in the first position and the shutter 64 is moved to the closed position, the engagement pin 854 of the shutter link 85 is pressed by the arm 861 of the coil spring 86 in the direction in which the shutter 64 moves to the closed position.

[0261] That is, when the third rotating link 84 is in the first position, the coil spring 86 contacts the gate link 85 and presses the gate link 85 in the direction in which the gate 64 moves to the closed position. In this state, there is a gap between the arm 861 of the coil spring 86 and the inner peripheral surface 844b of the connecting hole 844 in the operating cam 843.

[0262] In addition, when the link 8 is in the first position and the shutter 64 is moved to the closed position, the linear motion link 82 of the link 8 is pressed by the urging member 9 in the direction in which the shutter 64 moves to the closed position.

[0263] In this case, the pressing force of the urging member 9 pressing the linear link 82 toward the closed position is set to be greater than the pressing force of the coil spring 86 pressing the engagement pin 854 of the gate link 85 toward the closed position.

[0264] When a force toward the open position is applied to the gate 64 while the connecting rod 8 is in the first position and the gate 64 is moved to the closed position, if the force applied to the gate 64 is greater than the pressing force of the coil spring 86 on the gate connecting rod 85, the gate connecting rod 85 resists the pressing force of the coil spring 86 and moves toward the open position of the gate 64.

[0265] like Fig.34 As shown, if the gate link 85 moves toward the gate 64 to the open position, the third rotation link 84 connected to the linear link 82 does not rotate because the pressing force of the urging member 9 is set to be greater than the pressing force of the coil spring 86, and the arm 861 of the coil spring 86 is elastically deformed and moves upward. In this case, since there is a gap between the arm 861 and the inner peripheral surface 844b of the connecting hole 844, the arm 861 that has moved upward does not interfere with the inner peripheral surface 844b.

[0266] That is, when the third rotating link 84 is in the first position, if the gate 64 moves from the closed position to the open position, the coil spring 86 abutting against the gate link 85 is elastically deformed, and the third rotating link 84 is maintained in the first position. In this way, the third rotating link 84 of the link 8 is configured not to move from the first position to the second position when a force is applied to the gate 64 in the closed position to move to the open position.

[0267] If it is assumed that the third rotating link 84 moves from the first position to the second position when the gate 64 moves from the closed position to the open position when the third rotating link 84 is in the first position, then along with the movement of the third rotating link 84, the abutment piece 80 connected to the third rotating link 84 via the direct-acting link 82 etc. moves.

[0268] If the contact piece 80 moves, the second protrusion 804 of the contact piece 80 located at the front portion 242a of the contact piece rail 242 comes to the middle portion 242b (through hole 24C) of the contact piece rail 242. When the processing box 50 is subsequently assembled to the device body 2, the drum shaft 54a interferes with the second protrusion 804 and cannot abut against the first protrusion 803, and the normal movement of the connecting rod 8 may be hindered.

[0269] However, in the image forming device 1, when the third rotating link 84 is in the first position, if the gate 64 in the closed position moves toward the open position, the coil spring 86 abutting against the gate link 85 is elastically deformed, and the third rotating link 84 does not move but maintains the state of the first position, thereby preventing the subsequent movement of the link 8 from being obstructed.

[0270] In the present embodiment, the link 8 includes a contact piece 80, a first rotating link 81, a direct-acting link 82, a second rotating link 83, a third rotating link 84, a gate link 85, and a coil spring 86, but is not limited thereto. For example, a structure in which one link connected to the gate 64 contacts the process cartridge 50 may be adopted. In addition, the actions of the links of the link 8 are not limited to those of the present embodiment, and actions other than rotation and direct motion may be adopted.

[0271] In the present embodiment, the shutter 64 is opened and closed by the drum shaft 54 ​​a of the process cartridge 50 abutting against the abutting piece 80 of the link 8 , but the present invention is not limited thereto, and another part of the process cartridge 50 may abut against the link 8 .

[0272] In the present embodiment, the urging member 9 includes a pressing spring 92 and a pressing arm 91 pressed by the pressing spring 92 and in contact with the upper surface 82A of the linear link 82, but the present invention is not limited thereto, and may not be in the shape of a spring or an arm as long as it is a structure that presses the link 8. In addition, the pressing direction of the pressing spring 92 may be a structure that presses in other directions such as the left-right direction, the up-down direction, the front-back direction, etc., in addition to pressing downward as in the present embodiment.

[0273] In the present embodiment, when the shutter 64 moves to the open position, the contact end portion 64a contacts the contact surface 631 of the fixing frame 63, and the shutter 64 is positioned in the open position. However, the present embodiment is not limited to this, and the shutter 64 may be positioned in the open position by contacting a part of the connecting rod 8. For example, the apparatus body 2 may have a contact surface that contacts the direct-acting connecting rod 82 and the gate connecting rod 85 when the direct-acting connecting rod 83 and the gate connecting rod 85 open the shutter 64 to the maximum extent. Similarly, when the shutter 64 moves to the closed position, the contact portion 64b contacts the contact surface 632 of the fixing frame 63, and the shutter 64 is positioned in the closed position. However, the present embodiment is not limited to this, and the shutter 64 may be positioned in the closed position by contacting a part of the connecting rod 8 when the shutter 64 moves to the maximum closed position.

[0274] [Second Embodiment of the Operating Member for Moving the Link]

[0275] like Fig.35 As shown, the front cover 21 can also be used as an operating member for moving the link movable to a first position for moving the shutter to a closed position and a second position for moving the shutter to an open position. The front cover 21 is an example of an opening and closing cover as an operating member operated by a user.

[0276] exist Fig.35 In the image forming apparatus 1A shown, the link 8A can move between the first position and the second position according to the operation of the front cover 21. The link 8A is different from the link 8 in that it does not include the contact piece 80 and the first rotation link 81 and includes a linear link 182 instead of the linear link 82.

[0277] The front cover 21 is movable between an open position and a closed position by rotating about a rotating shaft 21 a .

[0278] The direct-acting link 182 is a substantially linear member that is rotatably connected to the front cover 21 and extends in the front-rear direction. The direct-acting link 182 has a fitting portion 1821 at the front end portion into which the protrusion 21b of the front cover 21 is rotatably fitted, and a connecting hole 1822 at the rear end portion. The direct-acting link 182 is connected to the front cover 21 by fitting the protrusion 21b to the fitting portion 1821, and moves linearly in the front-rear direction along with the rotation of the front cover 21.

[0279] The direct-acting link 182 moves from the front to the rear as the front cover 21 rotates from the open position to the closed position. As a result, the link 8A moves the shutter 64 from the closed position to the open position. Conversely, the direct-acting link 182 moves from the rear to the front as the front cover 21 rotates from the closed position to the open position. As a result, the link 8A moves the shutter 64 from the open position to the closed position.

[0280] That is, the shutter 64 moves to the open position when the front cover 21 is in the closed position, and moves to the closed position when the front cover 21 is in the open position. The position of the direct-acting link 182 that moves the shutter 64 to the closed position is the first position, and the position of the direct-acting link 182 that moves the shutter 64 to the open position is the second position.

[0281] The engagement pin 832a of the second rotating link 83 enters the connection hole 1822 of the linear link 182 from the right, and the engagement pin 832a and the connection hole 1822 are engaged with each other along the front-rear movement of the linear link 182. The linear link 182 is connected to the second rotating link 83 by the engagement pin 832a and the connection hole 1822.

[0282] Thus, the link 8A can move the shutter 64 from the closed position to the open position as the front cover 21 rotates from the open position to the closed position, and the link 8A can move the shutter 64 from the open position to the closed position as the front cover 21 rotates from the closed position to the open position.

[0283] In this way, by using the front cover 21 as an operating member for moving the link 8A, the shutter 64 can be moved to the open position and the closed position in accordance with the operation of opening and closing the front cover 21 .

[0284] Description of Reference Numerals

[0285] 1.1A Image forming device

[0286] 2 Device body

[0287] 6 Fuser

[0288] 8.8A Connecting rod

[0289] 9 Force-applying member

[0290] 21 Front cover

[0291] 24 First main frame

[0292] 24A front frame

[0293] 50 Processing Box

[0294] 54 Photosensitive drum

[0295] 54a Drum shaft

[0296] 61 Heating unit

[0297] 62 Pressure roller

[0298] 63 Fixing frame

[0299] 64 Gate

[0300] 80 Abutment sheet

[0301] 81 First rotating link

[0302] 82, 182 direct acting connecting rod

[0303] 82A Upper surface

[0304] 84 Third rotating link

[0305] 85 Gate connecting rod

[0306] 86 Coil spring

[0307] 91 Press Arm

[0308] 92 Compression spring

[0309] 241 Box Track

[0310] 242 Abutment track

[0311] 631 abutment surface

[0312] 632 abutment surface

[0313] 803 First Bump

[0314] 804 Second Bump

[0315] 823 Connecting rod protrusion

[0316] 823a First pressed surface

[0317] 823b Second pressed surface

[0318] 823c The third pressed surface

[0319] 911 Support

[0320] 912 Contact Department

[0321] NP clamping part

[0322] S sheet.

Claims

1. An image forming device, characterized in that: have: A fixing device having a heating portion and a pressurizing portion forming a nip with the heating portion, so as to fix the toner image to the sheet; a shutter capable of being displaced to a closed position covering a portion of the heating unit and an open position opening a portion of the heating unit; and The urging member urges the gate so as to maintain it at the closed position when the gate is in the closed position, and urges the gate so as to maintain it at the open position when the gate is in the open position.

2. The image forming apparatus according to claim 1, A switching mechanism is further provided for switching the urging direction of the urging member between a direction for urging so as to hold the shutter at the closed position and a direction for urging so as to hold the shutter at the open position.

3. The image forming apparatus according to claim 2, The switching mechanism further includes a link connected to the shutter and capable of being displaced to a first position for displacing the shutter to a closed position and a second position for displacing the shutter to an open position, wherein the urging member urges the link.

4. The image forming apparatus according to claim 3, The urging member includes a spring for urging the link and a pressing portion connected to the spring and pressing the link.

5. The image forming apparatus according to claim 4, The connecting rod has: a first portion that contacts the pressing portion when the link is at the first position to change the urging direction of the spring to a direction in which the link moves from the second position to the first position; and The second portion contacts the pressing portion when the link is at the second position to change the biasing direction of the spring to a direction in which the link moves from the first position to the second position.

6. The image forming apparatus according to claim 5, The first portion of the connecting rod is a first inclined surface inclined relative to the moving direction of the connecting rod. The second portion of the connecting rod is a second inclined surface inclined relative to the moving direction of the connecting rod, The inclination direction of the first inclined surface is different from the inclination direction of the second inclined surface.

7. The image forming apparatus according to claim 6, The spring of the urging member urges the pressing portion downward. The first inclined surface of the connecting rod has an inclined shape that rises along a moving direction of the connecting rod from the second position to the first position, The second inclined surface of the link has an inclined shape that rises along a moving direction of the link from the first position to the second position.

8. The image forming apparatus according to claim 4, The pressing portion is an arm having a rotation center at one end and a contact portion that contacts the link at the other end.

9. The image forming apparatus according to claim 3, An operating member that can be operated by a user to displace the link is also provided.

10. The image forming apparatus according to claim 9, The operating member is a cartridge that is attachable to and detachable from the image forming apparatus, and the shutter moves to the open position when the cartridge is attached to the image forming apparatus, and moves to the closed position when the cartridge is detached from the image forming apparatus.

11. The image forming apparatus according to claim 10, The cartridge has a photosensitive drum that rotates around a drum shaft. The link includes a contact piece that contacts the drum shaft, a first link that contacts the urging member, and a second link that is rotatably connected to the first link and rotatably connected to the contact piece.

12. The image forming apparatus according to claim 11, The drum shaft of the cartridge detached from the image forming apparatus abuts against the abutment piece to press the first link in a direction from the second position to the first position. Before the first link, which is pressed by the drum shaft and moves from the second position to the first position, reaches the first position, the drum shaft and the contact piece are separated. After the drum shaft and the contact piece are separated, the first link is urged in the direction from the second position to the first position by the urging force of the urging member and reaches the first position.

13. The image forming apparatus according to claim 1, The device further includes a restriction surface that abuts against the shutter in the closed position to restrict the position of the shutter.

14. The image forming apparatus according to claim 1, The link is configured not to move from the first position toward the second position when a force to move the shutter in the closed position toward the open position is applied.

15. The image forming apparatus according to claim 14, The connecting rod has: A gate connecting rod connected to the gate to move the gate to the open position and the closed position; a connecting rod cam connected to the gate connecting rod and capable of moving to the first position and the second position; and A link spring moves along the movement of the link cam to press the gate link, When the link cam is in the first position, the link spring contacts the gate link to press the gate link in a direction in which the gate moves to the closed position. When the link cam is at the first position, if the shutter moves from the closed position to the open position, the link spring abutting against the shutter link is elastically deformed, and the link cam maintains the state of being at the first position.

16. The image forming apparatus according to claim 9, The image forming apparatus includes an opening and an opening / closing cover as the operation member, the opening being movable to a closing position for closing the opening and an opening position for opening the opening. When the opening and closing cover is in the closed position, the gate moves to the open position, The shutter moves to the closed position when the opening and closing cover is in the open position.

Images