Image forming apparatus

Abstract

The invention discloses an image forming apparatus. In the image forming apparatus, the engagement mechanism includes a first engagement portion, and the pressure release mechanism includes a first engaged portion engaged with the first engagement portion. In a process in which the first opening / closing member is opened from the closed state, a first engaging portion on a second opening side of the first engaged portion urges the first engaged portion from the second opening side to reduce or release an urging force applied to the fixing nip portion. In a state in which the first opening / closing member is closed, the first engaging portion and the first engaged portion are disengaged, and when the fixing unit is detached from the second opening, the first engaging portion retracts from a path of the first engaged portion.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, and to a configuration for releasing a pressing force of a fixing device in conjunction with opening of a door to perform jam recovery when a paper jam (hereinafter referred to as a paper jam) occurs. Background Art

[0002] An image forming apparatus such as a printer and a fax machine includes a fixing device that fixes a toner image formed on a sheet to a sheet by applying heat and pressure to the toner image. The fixing device is configured so that a pressure member and a heating unit form a nip portion, and is configured to apply heat and pressure when the sheet passes through the nip portion, thereby fixing the toner image.

[0003] Japanese Patent Laid-Open No. 2010-032833 discusses a configuration in which pressure in a nip portion of a fixing device is released in conjunction with opening / closing of a door through a gear train mechanism.

[0004] In the configuration discussed in Japanese Patent Laid-Open No. 2010-032833, a gear train is assembled between an arm member connected to a door and a fixing device, and the fixing device cannot be removed from the image forming apparatus unless the gear is removed. Therefore, during maintenance service operation of the image forming apparatus, there is a concern that the removal of the fixing device takes a lot of time and effort. Summary of the invention

[0005] According to one aspect of the present invention, an image forming device includes: a fixing unit configured to fix a colorant image formed on a sheet onto the sheet, the fixing unit including a heating unit configured to heat the sheet, a pressure component configured to be in pressure contact with the heating unit to form a fixing nip portion for fixing, a pressing component configured to apply a pushing force to make the pressure component and the heating unit in pressure contact with each other, and a pressure release mechanism configured to reduce or release the pushing force applied to the fixing nip portion; and a device body configured to detachably accommodate the fixing unit, the device body including a first opening / closing component configured to be openable / closable to a first opening of the device body, a coupling mechanism that is coupled to the pressure release mechanism and the first opening / closing component and operates in conjunction with the opening / closing of the first opening / closing component, and a second opening for attaching / detaching the fixing unit, wherein the pressure release mechanism is in contact with the first opening / closing component to form a fixing nip portion for fixing, and the fixing unit is formed by a plurality of pressure release mechanisms. When the closing member is in a closed state, the pushing member applies the pushing force to the fixing clamping part, and moves through the engaging mechanism in the process of opening the first opening / closing member from the closed state, and the pressure releasing mechanism reduces or releases the pushing force applied to the fixing clamping part, wherein the engaging mechanism includes a first engaging portion, and the pressure releasing mechanism includes a first engaged portion engaged with the first engaging portion, wherein, during the process of opening the first opening / closing member from the closed state, the first engaging portion located on the second opening side of the first engaged portion pushes the first engaged portion from the second opening side to reduce or release the pushing force applied to the fixing clamping part, and wherein, when the first opening / closing member is closed, the first engaging portion and the first engaged portion are disengaged, and when the fixing unit is removed from the second opening, the first engaging portion retreats from the path of the first engaged portion.

[0006] Further features of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a cross-sectional view schematically showing the configuration of the image forming apparatus.

[0008] Figure 2A and Figure 2B is a schematic diagram of a fixing device.

[0009] Figure 3 is a cross-sectional view of the heating unit.

[0010] Figure 4A and Figure 4B is a schematic diagram showing a pressure release mechanism of the fixing device.

[0011] Figure 5A and Figure 5B is a schematic diagram of the front cam, rear cam and shaft components.

[0012] Figure 6 This is a perspective view of the rear door.

[0013] Fig. 7A and Figure 7B is an explanatory diagram showing the operation of the pressure release mechanism of the fixing device caused by the opening / closing of the rear door.

[0014] Figure 8 It is a perspective view of an engaging mechanism that engages with a pressure release mechanism of a fixing device in conjunction with a front door.

[0015] Fig.9A , Fig. 9B and Fig. 9C It is an explanatory diagram showing the operation of the front door and the engaging mechanism on the front side of the image forming apparatus main body.

[0016] Fig.10 : is an explanatory diagram showing the operation of the cam engaging member and the pressure release mechanism (when the front door is in a closed state).

[0017] Fig.11 1 is an explanatory diagram showing the operation of the cam engagement member and the pressure release mechanism (in a state where the cam engagement member starts to engage with the front cam).

[0018] Fig.12 : is an explanatory diagram showing the operation of the cam engagement member and the pressure release mechanism (in the process of releasing pressure).

[0019] Fig.13 : is an explanatory diagram showing the operation of the cam engaging member and the pressure release mechanism (when the front door is in an open state).

[0020] Fig.14A , Fig. 14B , Fig. 14C and Fig.14D It is an explanatory diagram showing a method of removing the rear door.

[0021] Fig.15A , Fig. 15B and Fig. 15C is an explanatory diagram illustrating an attachment / detachment locus of the fixing device according to the first exemplary embodiment.

[0022] Fig.16A , Fig. 16B and Fig. 16C is a perspective view showing the operation of the cam engagement member and the pressure release mechanism.

[0023] Fig.17A , Fig. 17Band Fig. 17C is a top view of the cam engagement components and pressure release mechanism operation.

[0024] Fig.18A , Fig.18B and Fig.18C is an explanatory diagram illustrating an attachment / detachment locus of the fixing device according to the second exemplary embodiment. DETAILED DESCRIPTION

[0025] The present invention is proposed in view of such circumstances and relates to an image forming apparatus capable of replacing a fixing device without impairing operability during removal of the fixing device in a structure in which a clamping portion of the fixing device is released in conjunction with opening of a door.

[0026] A first exemplary embodiment of the present invention is described below. Figure 1 2 is a cross-sectional view schematically showing the configuration of a monochrome laser printer as an example of an image forming apparatus. Note that the size, material, shape, relative arrangement, etc. of the components described in the following exemplary embodiments should be appropriately changed according to the configuration and various conditions of the apparatus to which the present invention is applied. Therefore, unless otherwise specified, the scope of the present invention is not limited to them. The entire configuration of the image forming apparatus is described, and then the configuration of the fixing device is described.

[0027] Figure 1 The image forming apparatus 101 shown mainly includes a sheet feeding unit, an image forming unit that forms an image on a sheet, a fixing unit, a sheet discharge / reversing unit, and a double-sided conveying unit. The image forming apparatus 101 includes a process cartridge 1 that is attachable to and detachable from a device body. The process cartridge 1 is a process unit for forming a toner image on a sheet by using an electrophotographic process, and includes a photosensitive drum 2 and a process unit (not shown) such as a developing unit and a charging roller.

[0028] The scanner unit 3 is disposed above the process cartridge 1 in the vertical direction, and performs exposure based on an image signal on the photosensitive drum 2. The photosensitive drum 2 is charged to a potential of a predetermined negative polarity by a charging roller (not shown). Then, the scanner unit 3 scans the photosensitive drum 2 with laser light. As a result, an electrostatic latent image is formed on the photosensitive drum 2. Then, a developing unit (not shown) in the process cartridge 1 causes toner to adhere to the electrostatic latent image on the photosensitive drum 2, thereby forming a toner image.

[0029] The sheet feeding unit includes a sheet feeding roller 4 inside the image forming device 101 and a sheet feeding cassette 5 that can be attached to and detached from the image forming device 101 and accommodates sheets. The sheets S accommodated in the sheet feeding cassette 5 are separated and fed one by one from the sheet feeding cassette 5 by the sheet feeding roller 4, which is rotated by the power of a sheet feeding driving unit (not shown). The fed sheet S is conveyed to the registration roller pair 7 by the conveying roller pair 6, skew-corrected by the registration roller pair 7, and then conveyed to the transfer unit. In the transfer unit, a bias of positive polarity is applied to the transfer roller 8 by a bias applying unit (not shown). As a result, the toner image on the photosensitive drum 2 is transferred to the sheet S conveyed to the transfer unit.

[0030] The sheet S to which the toner image has been transferred is conveyed to a fixing device (fixing unit) 9 provided on the downstream side of the transfer unit in the conveying direction. The fixing device 9 fixes the toner image transferred to the sheet S onto the sheet S. The fixing device 9 includes a heating unit 10 provided with a heater as a heating device (not shown), and a pressure roller 11 as a pressure member which is in pressure contact with the heating unit 10 and rotates around a rotation axis. The sheet S on which the toner image has been formed is clamped and conveyed by a fixing clamping portion N formed by the heating unit 10 and the pressure roller 11, and the toner image is fixed to the surface of the sheet S by receiving heat and pressure.

[0031] The sheet S to which the toner image has been fixed is conveyed from the fixing device 9 to the sheet discharge / reversal unit. The sheet discharge / reversal unit includes a triple roller and a double-sided flapper 12, and the triple roller includes a discharge roller 13, a discharge roller 14, and a reversal roller 15. In the case of single-sided image formation (single-sided printing), the double-sided flapper 12 stands by at a position to guide the sheet S toward a discharge nip portion formed by the discharge roller 13 and the discharge roller 14, and the sheet S is discharged onto a discharge tray 16 by the discharge roller 13 and the discharge roller 14.

[0032] In the case of double-sided image formation (double-sided printing), the double-sided flapper 12 stands by at a position where the sheet S is guided toward the reversing nip formed by the discharge roller 13 and the reversing roller 15, and the sheet S is conveyed to the reversing nip by the fixing device 9. At the timing when the trailing edge of the sheet S reaches the predetermined position, the discharge roller 13 is reversely rotated by the rotation direction switching unit (not shown). As a result, the sheet S passes through the double-sided conveying roller pair 17 and the re-feeding roller pair 18 with the trailing edge first, and is re-conveyed to the registration roller pair 7 in a state where the front and back sides of the sheet S are reversed. Then, the double-sided flapper 12 stands by at a position where the sheet S is guided toward the discharge nip formed by the discharge roller 13 and the discharge roller 14. In addition, in a manner similar to single-sided printing, the toner image on the photosensitive drum 2 is transferred to the second surface of the sheet S and fixed by the fixing device 9. Then, the sheet S is discharged onto the discharge tray 16 by the discharge roller 13 and the discharge roller 14, thereby completing the double-sided printing. In the event that the sheet S is jammed in the fixing device 9 during transport, jam recovery can be performed by opening the front door (first opening / closing member) 19 covering the first opening or the rear door (second opening / closing member) 20 covering the second opening, depending on the location where the jam occurs.

[0033] Next, refer to Figures 2A to 4B The fixing device 9 is described. Figure 2A is a schematic diagram of a fixing device 9 according to a first exemplary embodiment, Figure 2B 1 is a schematic diagram of a state in which the sheet conveying guide is removed from the fixing device 9. The fixing device 9 is detachably accommodated in the image forming apparatus 101. The fixing device 9 includes side plates 21 and 22, an upper support frame 23, and a lower support frame 24. A pressure roller 11 as a pressure member is rotatably supported relative to the side plates 21 and 22 via corresponding ball bearings 25 and bearings 26. The heating unit 10 is attached to the side plates 21 and 22 via corresponding flange members 28. The pressure roller 11 is arranged to face the heating unit 10 to form a fixing clamping portion N that clamps the sheet S.

[0034] Figure 3 2 is a cross-sectional view of the heating unit 10. The heating unit 10 mainly includes a heater 30, a pressure bracket 29, a fixing film 31, and a film guide 32. The fixing film 31 has a cylindrical shape (sleeve shape), is flexible, and is assembled to the film guide 32 from the outside. The heater 30 as a heating source is assembled and fixed to a groove provided in the longitudinal direction of the film guide 32. The pressure bracket 29 has a substantially U-shaped cross section, is provided inside the film guide 32, and presses the film guide and the heater 30 toward the pressure roller 11 when subjected to a pressing force.

[0035] Figure 4A and Figure 4B is from Figure 2BThe side view viewed from the direction A in FIG. 1 is a schematic diagram of the pressure mechanism and the pressure release mechanism in the fixing device 9. Figure 4A 1 is a diagram showing a contact state in which the heating unit 10 is pushed toward the pressure roller 11 and accordingly applies a predetermined pressing force thereto. Figure 4B 2 is a diagram showing a non-pressing state, in which the pressing force of the heating unit 10 toward the pressure roller 11 is reduced (or the pressing force is zero) compared to the contact state. The pressing plate 27 is pressed by the pressing spring 33, the pressing force is transmitted to the heating unit 10 via the flange member 28, and the heating unit 10 is urged toward the pressure roller 11, and a predetermined pressing force is applied to the fixing nip portion N.

[0036] The pressure release mechanism of the fixing device 9 includes a front cam (cam member) 34 that moves in conjunction with the opening / closing of the front door 19 and a rear cam 35 that pivots in conjunction with the opening / closing of the rear door 20. The pressure release mechanism of the fixing device 9 also includes a pressure release arm 36 that switches between a pressurized state and a non-pressurized state of the fixing nip portion N by raising the pressurizing plate 27, and a pressure release arm holder 40 that holds the pressure release arm 36. In the fixing device 9, the front cam 34 and the rear cam 35 are respectively pivoted in conjunction with the switching of the front door 19 and the rear door 20 from the closed state to the open state, and the state changes from the closed state to the open state. Figure 4A The contact status shown switches to Figure 4B Shown in non-pressurized state. Figure 4B The unpressurized state is shown, wherein both the front door 19 and the rear door 20 are open, and both the front cam 34 and the rear cam 35 have pivoted. Figure 5A and Figure 5B 3 is a diagram showing the relationship between the front cam 34, the rear cam 35 and the shaft member 37. Figure 5A and Figure 5B As shown, the front cam 34 and the rear cam 35 are held by the shaft member 37 so that the hole portion 35D of the rear cam 35 is engaged with the shaft portion 34D of the front cam 34 .

[0037] As a result, the front cam 34 and the rear cam 35 can pivot independently. When one of the front door 19 and the rear door 20 is in an open state, only the cam corresponding to the opened door pivots. The front cam 34, the rear cam 35, the pressure release arm 36 and the pressure release arm holder 40 are arranged at both ends of the fixing device 9 in the longitudinal direction, and the front cams 34 arranged at both ends are connected by a shaft member 37. The front cam 34 and the rear cam 35 each have a cam surface for lifting the pressure release arm 36, and pivot to place the fixing device 9 in a non-pressurized state. Since the front cam 34 and the rear cam 35 can pivot independently, when at least one of the front cam 34 and the rear cam 35 pivots, the fixing device 9 enters a non-pressurized state. In other words, when at least one of the front door 19 and the rear door 20 is in an open state, the fixing device 9 is in a non-pressurized state. Next, referring to Figure 6 The pressure release linked to the opening of the rear door 20 is described. Figure 6 is a perspective view showing the rear door 20 . Fig. 7A and Figure 7B 2 is an explanatory diagram showing the operation of the pressure release mechanism of the fixing device 9 when the rear door 20 is opened or closed, and is a cross-sectional view taken along the rear cam 35. Figure 6 As shown, the rear door 20 includes a first rear door engaging portion 20A and a second rear door engaging portion 20B at each end thereof for releasing the pressure of the fixing device 9. This is because, as described above, the rear cams 35 provided at both ends in the longitudinal direction of the fixing device 9 can pivot independently of each other. The first rear door engaging portion 20A and the second rear door engaging portion 20B can enable the rear cam 35 to pivot at both ends.

[0038] Then, refer to Fig. 7A and Figure 7B The operation of the pressure release mechanism of the fixing device 9 at the time of opening / closing of the rear door 20 is described. Fig. 7A When the rear door 20 is closed and the fixing nip N is in Figure 4A The diagram shows the pressurized state. Figure 7B When the rear door 20 is open and the fixing nip N is in Figure 4B 35F of the rear cam 35. As the rear door 20 begins to open, the first rear door engaging portion 20A of the rear door 20 contacts the surface 35G of the rear cam 35. As the rear door 20 opens further, the second rear door engaging portion 20B provided on the rear door 20 contacts the surface 35F of the rear cam 35. As a result, the rear cam 35 moves in conjunction with the pivoting of the rear door 20 in the opening direction. Fig. 7A and Figure 7B Finally, as Figure 7BAs shown, the rear cam 35 stops pivoting at a position where the arc portion 35B coaxial with the pivot center of the rear cam 35 contacts the pressure release arm 36. In this state, the second rear door engaging portion 20B and the surface 35F of the rear cam 35 contact each other. In the case where the rear door 20 moves from the open state to the closed state, the first rear door engaging portion 20A of the rear door 20 contacts the surface 35E of the rear cam 35 to pivot the rear cam 35 in the counterclockwise direction. Finally, the fixing device 9 is placed as shown in FIG. Figure 4A Contact status shown.

[0039] Next, refer to Figures 8 to 12 The pressure release linked to the opening of the front door 19 is described. Figure 8 1 is a perspective view showing a coupling mechanism that is coupled to the pressure release mechanism of the fixing device 9 in linkage with the front door 19. The coupling mechanism is a mechanism for performing pressurization and release of pressurization of the fixing clamping portion N in linkage with the opening / closing of the front door 19. The coupling mechanism includes a front door coupling member 38 that is coupled to the front door 19, a sliding member 50 that is movable in the horizontal direction, and a cam coupling member (swinging member) 51 that is coupled to the front cam 34 to pivot the front cam 34. In the present exemplary embodiment, the cam coupling member 51 is connected to the sliding member 50 so as to be pivotable around an axis parallel to the rotation axis of the pressure roller 11. However, the present exemplary embodiment is not limited to this configuration, and another member may be pivotably coupled between the cam coupling member 51 and the sliding member 50.

[0040] The front door engagement member 38 is pivotally held by the sliding member 50 and has a long hole 38A. A boss 19A extending from the front door 19 in the direction of the rotation axis of the front door 19 engages with the long hole 38A. The cam engagement member 51 is pivotally held by the shaft 50A of the sliding member 50 and includes a guide boss 51A, a first engagement portion 51B provided on the front end side of the U-shaped portion of the cam engagement member 51 for engaging with the front cam 34, and a second engagement portion 51C provided on the rear end side of the U-shaped portion. The front cam 34 includes a boss 34C for engaging with the first engagement portion 51B and the second engagement portion 51C. The guide boss 51A and the boss 34C of the front cam 34 are arranged parallel to each other, and the guide boss 51A engages with a guide groove 52 provided in the image forming device body. The sliding member 50 is held in the image forming device body by a portion (not shown) movable in the horizontal direction.

[0041] Then, refer to FIG. 9A to FIG. 13 The operation of the engagement mechanism in conjunction with the opening / closing operation of the front door 19 is described. 9A to 9C 1 and 2 are explanatory diagrams showing the operation of the engaging mechanism between the front door 19 and the front side of the image forming apparatus main body. Fig.9A 1 is a diagram showing a situation in which the front door 19 is in a closed state. Fig. 9Bis a diagram showing a state in which the sliding member 50 begins to move horizontally. Fig. 9C 19 is a diagram when the front door 19 is in an open state. Fig.9A When the front door 19 is pivoted in the clockwise direction, the boss 19A slides and moves in the long hole 38A, and the front door engaging member 38 pivots in the clockwise direction about the rotation axis 38C. At this time, the sliding member 50 does not move horizontally. Then, the end surface 38B of the long hole 38A and the boss 19A of the front door 19 contact each other, which results in Fig. 9B When the front door 19 further pivots, the boss 19A and the end surface 38B of the long hole 38A move while contacting each other, and the sliding member 50 moves horizontally by a predetermined distance L1. Finally, the sliding member 50 moves to Fig. 9C Shown in the open position.

[0042] Fig.10 1 is an explanatory diagram showing the operation of the cam engagement member 51 and the pressure release mechanism. Fig.10 1 is a diagram showing a situation in which the front door 19 is in a closed state. Figures 11 to 13 The operation of the cam engaging member 51 and the pressure release mechanism during the process of opening the front door 19 is shown in sequence. Fig.10 As shown, when the front door 19 is in the closed state, the first engaging portion 51B of the cam engaging member 51 is in a position separated from the boss 34C of the front cam 34. When the front door 19 is opened, the sliding member 50 moves horizontally. Then, the guide boss 51A of the cam engaging member 51 moves along the inclined surface 52A of the guide groove 52, and accordingly, the cam engaging member 51A moves while pivoting around the shaft 50A which is the engaging portion with the sliding member 50. As a result, the first engaging portion 51B moves upward, and the first engaging portion 51B contacts the first engaged portion 34E1 which is the left surface of the boss 34C of the front cam 34 in the figure from the second opening side, which results in the following situation: Fig.11 When the sliding member 50 further moves horizontally, the guide boss 51A of the cam engaging member 51 moves along the horizontal portion of the guide groove 52, and the cam engaging member 51A moves horizontally integrally with the sliding member 50. At this time, the first engaging portion 51B of the cam engaging member 51 causes the front cam 34 to pivot, which results in the following Fig.12 Status shown.

[0043] Finally, the sliding member 50 completes the movement of the predetermined distance L1, which results in Fig.13 Shown in non-pressurized state.

[0044] In the case where the front door 19 moves from the open state to the closed state, the cam engaging member 51 performs a movement opposite to the movement described so far. On the second opening side of the second engaging portion 51C of the cam engaging member 51, there is arranged the second engaged portion 34E2 which is the right surface of the boss 34C of the front cam 34 in the figure. In the process of the front door 19 moving from the open state to the closed state, the second engaging portion 51C of the cam engaging member 51 pushes the second engaged portion 34E2 of the front cam 34 toward the second opening, which causes the front cam 34 to pivot, and the pushing force is applied to the fixing clamping portion N accordingly. Fig.10 As shown, when the front door 19 is in the closed state, the first engaging portion 51B of the cam engaging member 51 and the second engaged portion 34E2 of the front cam 34 do not contact each other. Note that when the front door 19 is in the closed state, the cam engaging member 51 can move so that the second engaging portion 51C and the boss 34C contact each other. An exemplary embodiment in which the boss 34C includes the first engaged portion 34E1 and the second engaged portion 34E2 is described; however, the first engaged portion 34E1 and the second engaged portion 34E2 may be provided on different boss portions.

[0045] Subsequently, a procedure for disassembling the fixing device 9 is described. Fig.14A is a perspective view of the image forming apparatus 101 viewed from the left rear surface, Fig. 14B is an explanatory diagram showing a method of removing the rear door 20, Fig. 14C is a perspective view of the image forming apparatus 101 in a state where the rear door 20 has been removed, Fig.14D 2 is an explanatory diagram showing a method of disassembling the fixing device 9. The rear door 20 is formed by Fig.14A The rear cover 70 shown is pivotally supported. After removing the fastening screws 80, the rear door 20 and the rear cover 70 are removed as a whole. Fig. 14B As a result, the user can access the fixing device 9 to attach and detach the fixing device 9.

[0046] As described above, in the closed state of the front door 19, Fig.10 , when the fixing device 9 is removed from the image forming apparatus 101, the first engaging portion 51B is in a position retreated from the path along which the first engaged portion 34E1 moves. FIG. 15A to FIG. 15C As shown, the fixing device 9 is detachable in the X direction. The path of movement of the first engaged portion 34E1 is FIG. 15A to FIG. 15C The first engaged portion 34E1 moves forward as viewed from the second opening side. The fixing device 9 is replaceable without the user having to disengage the engaging portion between the engaging mechanism and the fixing device 9, and usability is not impaired.

[0047] The pressure release mechanism according to the present exemplary embodiment operates in linkage with the front door 19 and the rear door 20 independently of each other. Therefore, regardless of whether the pressure release mechanism that operates in linkage with the rear door 20 is in a pressurized state or a non-pressurized state, the fixing device 9 can be attached or detached when the front door 19 is in a closed state. In addition, in the present exemplary embodiment, when the fixing device 9 is detached from the image forming device 101, the first engaging portion 51B is in a position completely retracted from the path of the first engaging portion 34E1. However, the first engaging portion 51B may not be in a position completely retracted from the path. By pushing the first engaging portion 51B by the first engaged portion 34E1, the first engaging portion 51B can move the amount of gap between the engaging portions that constitute the engaging mechanism. In other words, this construction can make it possible for the first engaged portion 34E1 to push the first engaging portion 51B when the fixing device 9 is detached from the image forming device 101, so that the first engaging portion 51B is retracted from the path of the first engaged portion 34E1.

[0048] In the present exemplary embodiment, a configuration including three parts (i.e., the front door engaging member 38, the sliding member 50, and the cam engaging member 51) has been described as an engaging mechanism that engages with the fixing device 9 and operates in conjunction with the front door 19. However, the number of parts constituting the engaging mechanism is not limited to three. Therefore, unless otherwise specified, the functions, materials, shapes, arrangements, etc. of the components described in the above exemplary embodiments do not limit the present invention and can be appropriately changed within the spirit of the present invention.

[0049] Reference FIG. 16A to FIG. 17C A second exemplary embodiment of the present invention is described. Parts identical or equivalent to those according to the first exemplary embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The engagement mechanism according to the present exemplary embodiment includes a front door engagement member 38 coupled to the front door 19, a sliding member 60 movable in the horizontal direction, and a cam engagement member 61 engaged with the front cam 34 to pivot the front cam 34.

[0050] In the present exemplary embodiment, the cam engagement member 61 is pivotally connected to the shaft 60A of the sliding member 60. More specifically, the cam engagement member 61 is connected to the sliding member 60 so as to be pivotable around an axis orthogonal to the rotation axis of the pressure roller 11. Another member may be pivotally connected between the cam engagement member 61 and the sliding member 60. In addition, the cam engagement member 61 includes a guide boss 61A and an engagement portion 61B for engaging with the front cam 34. The front cam 34 includes a boss 34C for engaging with the engagement portion 61B, and the boss 34C extends. The guide boss 61A and the boss 34C of the front cam 34 are arranged to be orthogonal to each other, and the guide boss 61A engages with a guide groove 62 provided in the image forming device body. The sliding member 60 is held in the image forming device body by a portion (not shown) that is movable in the horizontal direction.

[0051] FIG. 16A to FIG. 16C is a diagram illustrating the operation of the cam engagement member 61 and the pressure release mechanism. 17A to 17C It is a top view from above the subject. Fig.16A and Fig.17A It is a diagram when the front door 19 is in a closed state. Fig. 16B and Fig. 17B This is a diagram of a state in which the cam engagement member 61 and the front cam 34 begin to engage with each other. Fig. 16C and Fig. 17C 1 is a diagram showing the front door 19 in an open state. When the front door 19 is in a closed state, the engaging portion 61B of the cam engaging member 61 is in a position separated from the boss 34C of the front cam 34, as shown in FIG. Fig.16A As shown. When the sliding member 60 starts to move horizontally, the guide boss 61A moves along the inclined surface 62A of the guide groove 62, and accordingly, the cam engaging member 61 moves and pivots around the shaft 60A of the sliding member 60 while moving horizontally. As a result, the engaging portion 61B moves in a direction approaching the fixing device 9, and contacts the boss 34C of the front cam 34, which results in the following Fig. 16B When the sliding member 60 further moves horizontally, the guide boss 61A of the cam engaging member 61 moves along the vertical portion of the guide groove 62, and the cam engaging member 61 moves horizontally integrally with the sliding member 60. At this time, the engaging portion 61B of the cam engaging member 61 causes the front cam 34 to pivot. Finally, the sliding member 60 moves horizontally in the same manner as the first exemplary embodiment. Fig. 9C The movement of the predetermined distance L1 is completed in the same manner as in Fig. 16C The non-pressurized state is shown in .

[0052] In the case where the front door 19 is moved from the open state to the closed state, an operation opposite to the operation described so far is performed. Fig.16A and Fig.17AWhen the front door 19 is in the closed state shown in FIG. 1 , the engagement mechanism (cam engagement member 61) is in a position retracted from the attachment / detachment path of the fixing device 9. 18A to 18C As shown, the fixing device 9 is attachable or detachable in the X direction. The fixing device 9 is replaceable without the user having to disengage the engaging portion between the engaging mechanism and the fixing device 9, and usability is not impaired.

[0053] Furthermore, the pressure release mechanism according to the present exemplary embodiment operates in linkage with the front door 19 and the rear door 20 independently of each other. Therefore, regardless of whether the pressure release mechanism operating in linkage with the rear door 20 is in a pressurized state or a non-pressurized state, the fixing device 9 can be attached or detached when the front door 19 is in a closed state. Furthermore, in the present exemplary embodiment, the cam engaging member 61 is in a position completely retracted from the attachment / detachment path of the fixing device 9. However, the cam engaging member 61 may not be in a position completely retracted from the path. For example, during the disassembly process of the fixing device 9, the front cam 34 may push the cam engaging member 61 to pivot, thereby retracting the cam engaging member 61 from the attachment / detachment path.

[0054] In the present exemplary embodiment, a configuration including three parts (i.e., the front door engaging member 38, the sliding member 60, and the cam engaging member 61) has been described as an engaging mechanism that engages with the fixing device 9 and operates in conjunction with the front door 19. However, the number of parts constituting the engaging mechanism is not limited to three. Therefore, unless otherwise specified, the functions, materials, shapes, arrangements, etc. of the components described in the above exemplary embodiments do not limit the present invention and can be appropriately changed within the spirit of the present invention.

[0055]

Additional statement

[0056] The above exemplary embodiments discuss at least the image forming apparatus described below.

[0057] (Item 1)

[0058] 1. An image forming device, comprising:

[0059] a fixing unit configured to fix a toner image formed on a sheet onto the sheet, the fixing unit including a heating unit configured to heat the sheet, a pressure member configured to be in pressure contact with the heating unit to form a fixing nip portion for fixing, an urging member configured to apply an urging force to bring the pressure member and the heating unit into pressure contact with each other, and a pressure releasing mechanism configured to reduce or release the urging force applied to the fixing nip portion; and

[0060] an apparatus body configured to detachably accommodate the fixing unit, the apparatus body comprising a first opening / closing member configured to be openable / closable toward a first opening of the apparatus body, an engaging mechanism engaged with the pressure release mechanism and the first opening / closing member and operating in conjunction with the opening / closing of the first opening / closing member, and a second opening for attaching / detaching the fixing unit,

[0061] wherein the urging member applies the urging force to the fixing nip portion in a state where the first opening / closing member is closed, and the pressure release mechanism reduces or releases the urging force applied to the fixing nip portion by moving the first opening / closing member in a process of opening the first opening / closing member from a closed state through the engagement mechanism,

[0062] wherein the engagement mechanism comprises a first engagement portion, and the pressure release mechanism comprises a first engaged portion engaged with the first engagement portion,

[0063] wherein, in the process of the first opening / closing member opening from the closed state, the first engaging portion located on the second opening side of the first engaged portion pushes the first engaged portion from the second opening side to reduce or release the pushing force applied to the fixing nip portion, and

[0064] Here, in a state where the first opening / closing member is closed, the first engaging portion and the first engaged portion are disengaged, and when the fixing unit is removed from the second opening, the first engaging portion retreats from a path of the first engaged portion.

[0065] (Item 2)

[0066] 2. The image forming apparatus according to item 1, wherein the first engaging portion is engaged with the first engaged portion in a process of opening the first opening / closing member.

[0067] (Item 3)

[0068] 3. The image forming apparatus according to items 1 and 2,

[0069] Wherein, the engagement mechanism comprises a second engagement portion,

[0070] Wherein, the pressure release mechanism comprises a second engaged portion,

[0071] wherein the second engaged portion is located on the second opening side of the second engaging portion, and

[0072] Here, in the process of closing the first opening / closing member, the second engaging portion engages with the second engaged portion, and the second engaged portion pushes the second engaged portion, so that the urging force is applied to the fixing nip portion.

[0073] (Item 4)

[0074] 4. The image forming apparatus according to items 1 to 3, wherein the first engaging portion is located on the second opening side of the second engaging portion.

[0075] (Item 5)

[0076] 5. The image forming apparatus according to items 1 to 4, wherein the pressure release mechanism includes a pivotable cam member that adjusts the urging force by acting on the urging member, and the cam member includes the first engaged portion.

[0077] (Item 6)

[0078] 6. The image forming apparatus according to any one of items 1 to 5,

[0079] wherein the pressure member is a pressure roller having a rotating shaft,

[0080] wherein the engagement mechanism includes a sliding member held to be movable in a horizontal direction in response to opening / closing of the first opening / closing member, and a swinging member held by the sliding member to be pivotable about an axis parallel to the rotation axis of the pressure roller, and

[0081] Wherein, the swing component includes the first engaging portion.

[0082] (Item 7)

[0083] 7. The image forming apparatus according to any one of items 1 to 5,

[0084] wherein the pressure member is a pressure roller including a rotating shaft,

[0085] wherein the engagement mechanism includes a sliding member held to be movable in a horizontal direction in response to opening / closing of the first opening / closing member, and a swinging member held to the sliding member to be pivotable about an axis orthogonal to the rotation axis of the pressure roller, and

[0086] Wherein, the swing component includes the first engaging portion.

[0087] (Item 8)

[0088] 8. The image forming apparatus according to any one of items 1 to 7,

[0089] wherein the apparatus body includes a second opening / closing member for recovering a paper jam at the fixing nip portion at a position covering at least a portion of the second opening, and

[0090] The opening / closing operation of the second opening / closing member reduces or releases the urging force applied to the fixing nip portion by interlocking with the pressure release mechanism.

[0091] (Item 9)

[0092] 9. The image forming apparatus according to item 8, wherein the opening / closing operation of the second opening / closing member is not linked to the engaging mechanism.

[0093] According to the exemplary embodiment, in a structure in which the clamping of the fixing device is released in conjunction with the opening of the door, it is possible to provide an image forming apparatus capable of replacing the fixing device without impairing the workability when the fixing device is disassembled.

[0094] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming device, comprising: a fixing unit configured to fix a toner image formed on a sheet onto the sheet, the fixing unit including a heating unit configured to heat the sheet, a pressure member configured to be in pressure contact with the heating unit to form a fixing nip portion for fixing, an urging member configured to apply an urging force to bring the pressure member and the heating unit into pressure contact with each other, and a pressure releasing mechanism configured to reduce or release the urging force applied to the fixing nip portion; as well as an apparatus body configured to detachably accommodate the fixing unit, the apparatus body comprising a first opening / closing member configured to be openable / closable toward a first opening of the apparatus body, an engaging mechanism engaged with the pressure release mechanism and the first opening / closing member and operating in conjunction with the opening / closing of the first opening / closing member, and a second opening for attaching / detaching the fixing unit, wherein the urging member applies the urging force to the fixing nip portion in a state where the first opening / closing member is closed, and the pressure release mechanism reduces or releases the urging force applied to the fixing nip portion by moving the first opening / closing member in a process of opening the first opening / closing member from a closed state through the engagement mechanism, wherein the engagement mechanism comprises a first engagement portion, and the pressure release mechanism comprises a first engaged portion engaged with the first engagement portion, wherein, in the process of the first opening / closing member opening from the closed state, the first engaging portion located on the second opening side of the first engaged portion pushes the first engaged portion from the second opening side to reduce or release the pushing force applied to the fixing nip portion, and Here, in a state where the first opening / closing member is closed, the first engaging portion and the first engaged portion are disengaged, and when the fixing unit is removed from the second opening, the first engaging portion retreats from a path of the first engaged portion.

2. The image forming apparatus according to claim 1, wherein: In the process of opening the first opening / closing member, the first engaging portion is engaged with the first engaged portion.

3. The image forming apparatus according to claim 1, in, The engagement mechanism comprises a second engagement portion, Wherein, the pressure release mechanism comprises a second engaged portion, wherein the second engaged portion is located on the second opening side of the second engaging portion, and Here, in the process of closing the first opening / closing member, the second engaging portion engages with the second engaged portion, and the second engaged portion pushes the second engaged portion, so that the urging force is applied to the fixing nip portion.

4. The image forming apparatus according to claim 3, wherein: The first engaging portion is located on the second opening side of the second engaging portion.

5. The image forming apparatus according to claim 1, wherein: The pressure release mechanism includes a pivotable cam member that adjusts the urging force by acting on the urging member, and the cam member includes the first engaged portion.

6. The image forming apparatus according to claim 1, in, The pressure member is a pressure roller having a rotating shaft, wherein the engagement mechanism includes a sliding member held to be movable in a horizontal direction in response to opening / closing of the first opening / closing member, and a swinging member held by the sliding member to be pivotable about an axis parallel to the rotation axis of the pressure roller, and Wherein, the swing component includes the first engaging portion.

7. The image forming apparatus according to claim 1, in, The pressure member is a pressure roller including a rotating shaft, wherein the engagement mechanism includes a sliding member held to be movable in a horizontal direction in response to opening / closing of the first opening / closing member, and a swinging member held to the sliding member to be pivotable about an axis orthogonal to the rotation axis of the pressure roller, and Wherein, the swing component includes the first engaging portion.

8. The image forming apparatus according to claim 1, in, The apparatus body includes a second opening / closing member for jam recovery at the fixing nip portion at a position covering at least a portion of the second opening, and The opening / closing operation of the second opening / closing member reduces or releases the urging force applied to the fixing nip portion by interlocking with the pressure release mechanism.

9. The image forming apparatus according to claim 8, wherein: The opening / closing operation of the second opening / closing member is not linked to the engagement mechanism.

Images