Image forming apparatus

Abstract

An image forming apparatus includes: an apparatus main body provided with an opening portion; an opening / closing member supported so as to be openable and closable between a closed position and an open position with respect to the apparatus main body; a fixing unit; and a moving unit provided in the apparatus main body and configured to move the fixing unit from the first position toward the second position. In a state in which the opening / closing member is positioned at the closed position, movement of the fixing unit from the first position to the second position is restricted, and in a state in which the opening / closing member is positioned at the open position, movement of the fixing unit from the first position to the second position is permitted. The moving unit includes: a support portion configured to support the fixing unit positioned at the second position; and a restricting portion configured to restrict falling of the fixing unit supported by the supporting portion from the supporting portion.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus for forming a toner image on a sheet. Background Art

[0002] Japanese Patent Application Laid-Open No. 2012-047806 discloses an image forming apparatus including a pair of arm members pivotally disposed relative to an apparatus main body, and a fixing unit held at distal ends of the arm members. The fixing unit is configured to be movable between an internal attachment position and a temporary holding position by pivoting the pair of arm members, the temporary holding position being closer to an opening portion of the apparatus main body than the internal attachment position.

[0003] However, when a strong external force is applied to the fixing unit described in Japanese Patent Application Laid-Open No. 2012-047806, the fixing unit may fall off the pair of arm members. For example, when removing a jammed sheet held in the fixing unit, the fixing unit may fall off the arm members due to the user pulling the sheet. Summary of the Invention

[0004] According to one aspect of the present invention, an image forming apparatus is configured to form a toner image on a sheet, the image forming apparatus comprising: an apparatus body provided with an opening portion; an opening and closing member supported so as to be openable and closable relative to the apparatus body between a closed position in which the opening portion is covered and an open position in which the opening portion is opened; a fixing unit supported so as to be attachable to and detachable from the apparatus body via the opening portion and configured to fix the toner image to the sheet by applying heat and pressure to the sheet; and a moving unit provided in the apparatus body and configured to move the fixing unit from a first position toward a second position different from the first position. When the opening and closing member is positioned in the closed position, movement of the fixing unit from the first position to the second position is restricted, while when the opening and closing member is positioned in the open position, movement of the fixing unit from the first position to the second position is permitted. The moving unit includes a supporting portion configured to support the fixing unit positioned at the second position, and a restricting portion configured to restrict the fixing unit supported by the supporting portion from falling from the supporting portion.

[0005] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a cross-sectional view of an imaging device.

[0007] Figure 2 is a perspective view showing a state in which the fixing unit has been detached from the moving unit.

[0008] Figure 3 is a sectional view of the imaging apparatus in a state where the door is opened.

[0009] Figure 4 is a sectional view of the image forming apparatus in a state in which the fixing unit has been lifted to the second position.

[0010] Figure 5 is a sectional view of the image forming apparatus in a state where the transfer unit and the tray unit have been pulled out through the opening portion.

[0011] Figure 6A is a perspective view of the imaging apparatus in a state where the door is opened.

[0012] Figure 6B is a perspective view of the fixing unit positioned at the second position.

[0013] Figure 7A It is an enlarged perspective view of the restricting member and the locking member located on the left side.

[0014] Figure 7B It is an enlarged perspective view of the restricting member, the locking member, and the cancel lever located on the right side.

[0015] Figure 8 is a perspective view showing a state in which the locking member has moved to the disassembly allowing position.

[0016] Figure 9 It is a cross-sectional view showing a state in which the pressing rib of the door presses the locking member.

[0017] Figure 10 is a sectional view showing a state in which the top surface of the door presses the restriction member.

[0018] Figure 11 is a perspective view showing how jam removal is performed on a sheet held in the fixing unit. DETAILED DESCRIPTION

[0019] Overall structure

[0020] The image forming apparatus 1 according to the present embodiment is a full-color laser beam printer of an electrophotographic system. Figure 1 is a cross-sectional view of the imaging apparatus 1 .

[0021] It should be noted that examples of imaging devices include printers, copiers, fax machines, and multifunction devices. These devices form images on sheets serving as recording media based on image information input from an external personal computer (PC) or read from a document. Furthermore, there are cases where a peripheral device such as an optional feeder, image reader, or sheet processing device is attached to a main body having imaging functionality, and the entire system including the peripheral device also functions as an imaging device. Examples of sheets include paper (such as paper and envelopes), plastic film (such as sheets for overhead projectors), and cloth.

[0022] like Figure 1 As shown, the imaging device 1 includes a device body 1A having an opening portion 9, and a door 20 serving as an opening and closing member. The door 20 is supported relative to the device body 1A so as to be openable and closable between a closed position, in which the door 20 covers the opening portion 9, and an open position, in which the door 20 opens the opening portion 9. The door 20 is configured to pivot about a pivot shaft 20b. It should be noted that the frame and exterior of the device body 1A and the door 20 may also be collectively referred to as the main frame 10.

[0023] The apparatus body 1A houses an imaging unit 70, a feeding unit 30, a fixing unit 80, a discharge unit 130, and a moving unit 140, which will be described below, for forming an image on a sheet S. The imaging unit 70 includes a transfer unit 40, a tray unit 50 disposed above the transfer unit 40, and a scanner 2 disposed above the tray unit 50.

[0024] The tray unit 50 includes a tray 51 that can be pulled out from the apparatus body 1A, and four process cartridges PY, PM, PC, and PK, which form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). The four process cartridges PY, PM, PC, and PK are placed on the tray 51. The tray 51 includes a tray handle 52 that can be grasped by the user.

[0025] It should be noted that the four process cartridges PY, PM, PC, and PK have the same configuration except for the color of the image formed thereby. Therefore, only the configuration and image forming process of the process cartridge PY will be described, and descriptions of the process cartridges PM, PC, and PK will be omitted.

[0026] The process cartridge PY includes a photosensitive drum 61, a charging roller 62, and a developing roller 71. The photosensitive drum 61 is formed by applying an organic photoconductive layer to the outer peripheral surface of an aluminum cylinder and is rotated by a drive motor (not shown). The directions of the rotation axes of the photosensitive drum 61, the developing roller 71, and the charging roller 62 are parallel to each other.

[0027] The transfer unit 40 includes a drive roller 46, a tension roller 47, and an intermediate transfer belt 41 looped around the drive roller 46 and the tension roller 47. Primary transfer rollers 42Y, 42M, 42C, and 42K are provided on the inner circumference of the intermediate transfer belt 41. Furthermore, a secondary transfer roller 45 is provided opposite the drive roller 46, with the intermediate transfer belt 41 positioned therebetween. The intermediate transfer belt 41 and the secondary transfer roller 45 form a transfer nip where an image is transferred to a sheet S conveyed thereto. It should be noted that an optical sensor 44 is provided in the imaging unit 70 to detect the toner image transferred to the intermediate transfer belt 41. The rotational axes of the primary transfer rollers 42Y, 42M, 42C, and 42K, the drive roller 46, the tension roller 47, and the secondary transfer roller 45 are parallel to one another.

[0028] The feeding unit 30 is provided in the lower portion of the image forming apparatus 1 and includes a cassette 31 that supports the sheet S and a pickup roller 32 that feeds the sheet S supported by the cassette 31. The cassette 31 is configured to be attachable to and detachable from the apparatus main body 1A on the same side as the opening portion 9. The discharge unit 130 includes a discharge roller pair 131 and a discharge tray 1f that supports the sheet S discharged by the discharge roller pair 131.

[0029] The fixing unit 80 includes a fixing portion 81 that fixes the toner image on the sheet to the sheet by applying heat and pressure to the sheet; a guide member 5; and a pair of reverse conveying rollers 132. The fixing portion 81 includes a heating roller 83 as a heating unit including a heater (not shown); and a pressure roller 84. The heating roller 83 and the pressure roller 84 form a fixing nip that clamps the sheet S. The guide member 5 is configured to be pivotable between a discharge position and a reverse conveying position. At the discharge position, the guide member 5 guides the sheet S toward the discharge path 1d, and at the reverse conveying position, the guide member 5 guides the sheet S toward the reverse conveying path 1e.

[0030] Next, the image forming operation of the image forming apparatus 1 configured in this manner will be described. The image forming apparatus 1 includes a controller 3 connected to an external host device 110. The controller 3 controls the scanner 2 based on an image signal received from the external host device 110 or a reading unit to irradiate a laser beam corresponding to the image signal onto the photosensitive drum 61 of the process cartridge PY. Examples of the external host device 110 include a personal computer, an image reader, and a facsimile machine.

[0031] At this time, the surface of the photosensitive drum 61 is uniformly charged to a predetermined polarity and potential by the charging roller 62, and the surface is irradiated with laser light from the scanner 2, thereby forming an electrostatic latent image thereon. The electrostatic latent image formed on the photosensitive drum 61 is developed by the developing roller 71, and a yellow (Y) toner image is formed on the photosensitive drum 61.

[0032] It should be noted that the developing roller 71 is configured to be able to contact and disconnect with the photosensitive drum 61. By separating the developing roller 71 from the photosensitive drum 61 when the image forming apparatus 1 is not performing an image forming operation, the service life of the photosensitive drum 61 and the developing roller 71 can be extended.

[0033] Similarly, laser light from scanner 2 irradiates the corresponding photosensitive drums of process cartridges PM, PC, and PK, forming magenta (M), cyan (C), and black (K) toner images on the corresponding photosensitive drums. The corresponding color toner images formed on the corresponding photosensitive drums are transferred to intermediate transfer belt 41 by primary transfer rollers 42Y, 42M, 42C, and 42K, and then conveyed to the transfer nip by intermediate transfer belt 41, which is rotated by drive roller 46. It should be noted that the image formation process for each color is performed at a timing such that each toner image formed by a process cartridge located further downstream is superimposed on the toner image already formed by a process cartridge located further upstream and transferred to intermediate transfer belt 41 through primary transfer. Furthermore, residual toner remaining on the photosensitive drum 61 is removed by a cleaning blade.

[0034] In parallel with this image forming process, the sheet S housed in the cassette 31 of the feed unit 30 is fed to the transport path 1c by the pickup roller 32. Then, the skew of the sheet S is corrected by the registration roller pair 4 provided in the transport path 1c, and the sheet S is transported at a predetermined transport timing that matches the transfer timing of the image at the transfer nip.

[0035] The full-color toner image on the intermediate transfer belt 41 is then transferred to the sheet S at the transfer nip by a secondary transfer bias applied to the secondary transfer roller 45. Residual toner remaining on the intermediate transfer belt 41 is also removed by a cleaning blade 43A provided in the cleaning section 43. The sheet S, to which the toner image has been transferred, is then subjected to predetermined heat and pressure applied by the heating roller 83 and pressure roller 84 of the fixing unit 80, causing the toner to melt and adhere (fix) to the sheet. The sheet S, having passed through the fixing unit 80, is guided by the guide member 5 to either the discharge path 1d or the reverse transport path 1e.

[0036] When a single-sided print job for printing an image on only one surface is input, the guide member 5 is positioned at the discharge position and the sheet S is guided to the discharge path 1d. The sheet S guided to the discharge path 1d is discharged to the outside of the apparatus by the discharge roller pair 131 and supported by the discharge tray 1f.

[0037] When a duplex print job in which an image is formed on each surface of a sheet S is input, the sheet S, having an image formed on its first surface at the transfer nip, is guided to the reverse conveyance path 1e by the guide member 5 positioned at the reverse conveyance position. After the trailing end of the sheet S passes through the guide member 5, the reverse conveyance roller pair 132 provided in the reverse conveyance path 1e rotates in the reverse direction, thereby inverting the sheet S. Simultaneously, the guide member 5 moves to the discharge position, and the inverted sheet S is guided by the guide member 5 to the duplex conveyance path 20a.

[0038] The sheet S guided to the duplex transport path 20a is transported to the transport path 1c by a plurality of transport roller pairs, where an image is formed on the second surface of the sheet S at the transfer nip. The toner image is then fixed to the sheet S by the fixing unit 80 as described above, and the sheet S is then discharged onto the discharge tray 1f by the discharge roller pair 131.

[0039] Schematic structure of the mobile unit

[0040] Next, we will refer to Figure 2 The mobile unit 140 is described. Figure 2 is a perspective view showing a state in which the fixing unit 80 has been detached from the moving unit 140 .

[0041] The moving unit 140 is provided between the right side plate and the left side plate constituting a part of the main frame 10, and Figure 2 The figure includes a support portion 90 and a lifting portion 100. The lifting portion 100 includes an arm unit disposed on one side of the fixing unit 80 in the longitudinal direction LD, and an arm unit disposed on the other side of the fixing unit 80 in the longitudinal direction LD. The two arm units have substantially the same structure, so only the arm unit located on one side (the right side) of the fixing unit 80 in the longitudinal direction LD will be described. It should be noted that the longitudinal direction LD is a direction perpendicular to the vertical direction VD and parallel to the horizontal direction.

[0042] like Figure 2 and Figure 4 As shown in FIG. 1 , the arm unit includes arms 101aR, 101bR, and 101cR and pushing members 102aR and 102bR that push the arms 101aR, 101bR, and 101cR. The arms 101aR, 101bR, and 101cR constitute a link mechanism. It should be noted that, although the pushing members 102aR and 102bR are all composed of coil springs in the present embodiment, the construction is not limited thereto. For example, the pushing members 102aR and 102bR can each be composed of different springs such as leaf springs, and the pushing members 102aR and 102bR can be composed of multiple springs.

[0043] The support portion 90 includes a metal frame 91 and a shaft member 92 extending along the longitudinal direction LD. The metal frame 91 is formed into a generally C-shape in plan view and is coupled to the shaft member 92, giving the support portion 90 an overall rectangular shape. This improves the rigidity of the support portion 90. The support portion 90 is coupled to the elevating portion 100 and moves up and down together with the elevating portion 100. The support portion 90 supports the bottom surface of the fixing unit 80. In other words, the support portion 90 supports the fixing unit 80 from below, allowing the fixing unit 80 to be attached and detached.

[0044] In a state where the door 20 is positioned at the closed position, the fixing unit 80 is as shown in FIG. Figure 1 As shown, the fixing unit 80 is housed in the image forming apparatus 1 and is positioned at a first position where the fixing unit 80 can fix the toner image to the sheet S during the image forming operation. In a state where the fixing unit 80 is supported by the supporting portion 90, the moving unit 140 can move the fixing unit 80 to the position as shown. Figure 6B In the following description, the position of the moving unit 140 when the door 20 is positioned in the closed position will be referred to as the accommodated position, and the position of the moving unit 140 that can support the fixing unit 80 positioned in the second position will be referred to as the supporting position. That is, the moving unit 140 is configured to be able to move from the accommodated position ( Figure 1 shown) moves upward to the support position ( Figure 2 shown in the location).

[0045] Movement of the transfer unit and tray unit

[0046] Next, we will refer to Figures 3 to 5 The movements of the transfer unit 40 and the tray unit 50 are described. Figure 3 is a sectional view of the image forming apparatus 1 in a state where the door 20 is open. Figure 4 is a cross-sectional view of the image forming apparatus 1 in a state where the fixing unit 80 is moved upward to the second position. Figure 5 1 is a sectional view of the image forming apparatus 1 in a state where the transfer unit 40 and the tray unit 50 have been pulled out through the opening portion 9 .

[0047] like Figure 3 As shown in FIG. 1 , when the door 20 is opened, the opening portion 9 of the apparatus body 1A is opened. When the door 20 is moved to the open position, the fixing unit 80 is exposed to the outside of the image forming apparatus 1 via the opening portion 9. Specifically, as shown in FIG. Figures 1 to 3As shown, the door 20 includes a side surface 20c constituting one side surface of the imaging device 1 and a top surface 20d constituting a portion of the top surface of the imaging device 1, and is generally L-shaped. Specifically, when the door 20 is moved to the open position, the space above the fusing unit 80, which was previously covered by the top surface 20d of the door 20 when in the closed position, is opened. Thus, the fusing unit 80 can move upward from the first position toward the second position. In other words, when the door 20 is in the closed position, movement of the fusing unit 80 from the first position to the second position is restricted, while when the door 20 is in the open position, movement of the fusing unit 80 from the first position to the second position is permitted. It should be noted that in this embodiment, when viewed along the longitudinal direction LD, the fusing unit 80 in the first position does not overlap with the door 20 in the closed position, whereas when viewed along the longitudinal direction LD, the fusing unit 80 in the second position at least partially overlaps with the door 20 in the open position.

[0048] Furthermore, as the door 20 is opened from the closed position to the open position, the opening portion 9 is opened, thereby exposing the conveying path 1c and the duplex conveying path 20a. Therefore, sheets S jammed in the conveying path 1c or the duplex conveying path 20a can be removed. Furthermore, the door 20 pivotally supports the secondary transfer frame 25, which supports the secondary transfer roller 45. By pivoting the secondary transfer frame 25 while the door 20 is in the open position, the duplex conveying path 20a can be opened to a wide range.

[0049] In addition, if Figure 4 As shown, when the fixing unit 80 is moved to the second position due to the upward movement of the moving unit 140 from the accommodated portion to the supporting position, a space is generated below the fixing unit 80. Therefore, the transfer unit 40 and the tray unit 50, which are image forming sections for forming a toner image on a sheet, are attachable to and detachable from the apparatus main body 1A via the opening portion 9 and the space below the fixing unit 80.

[0050] When the moving unit 140 has been moved upward to the supporting position, the transfer unit 40 and the tray unit 50 can be attached to and detached from the apparatus main body 1A even when the fixing unit 80 is attached to the supporting portion 90. That is, when the fixing unit 80 is positioned at the second position, the transfer unit 40 and the tray unit 50 can be attached to and detached from the apparatus main body 1A via the opening portion 9. The transfer unit 40 and the tray unit 50 can be pulled out of the apparatus main body 1A or attached to the apparatus main body along a cross direction ID that intersects both the vertical direction VD and the longitudinal direction LD. The cross direction ID and the longitudinal direction LD are parallel to a horizontal plane.

[0051] like Figure 5As shown, in a state where the transfer unit 40 and the tray unit 50 have been pulled out to the outside of the apparatus body 1A, the process cartridges PY, PM, PC, and PK can be attached to and detached from the tray 51. Therefore, the process cartridges PY, PM, PC, and PK can be replaced. In addition, the transfer unit 40 can also be replaced.

[0052] As described above, the fixing unit 80, the transfer unit 40, and the tray unit 50 are all configured to be attachable to and detachable from the imaging apparatus 1 on the door 20 side. Therefore, when attaching or detaching the fixing unit 80, the transfer unit 40, and the tray unit 50, the imaging apparatus 1 can be accessed from one side, which improves usability and reduces the installation space for installing the imaging apparatus 1. Furthermore, since the cartridge 31 is also configured to be attachable to and detachable from the apparatus main body 1A on the same side as the opening portion 9, usability can be improved and the required space can be reduced.

[0053] At the same time, the fixing unit 80 positioned at the first position overlaps the movement path of the transfer unit 40 and the tray unit 50 for attaching to and detaching from the apparatus main body 1A. Therefore, the imaging apparatus 1 can be miniaturized. It should be noted that in this embodiment, the transfer unit 40 and the tray unit 50 are configured to be attachable to and detachable from the apparatus main body 1A independently of each other, but may also be configured to be attachable to and detachable from the apparatus main body 1A as a single unit.

[0054] Attaching / detaching operation of the fixing unit

[0055] Next, we will refer to Figure 2 and Figures 6A to 10 The attaching / detaching operation of the fixing unit 80 is described. Figure 6A is a sectional view of the image forming apparatus 1 in a state where the door 20 is opened. Figure 6B is a perspective view of the fixing unit 80 positioned at the second position. Figure 7A is an enlarged perspective view of the restriction member 111L and the locking member 112L provided on the left side, Figure 7B It is an enlarged perspective view of the restriction member 111R, the lock member 112R, and the release lever 113 provided on the right side. Figure 8 112L and 112R are perspective views showing a state in which the locking members 112L and 112R have moved to the disassembly allowing positions. Figure 9 112L and 112R are cross-sectional views showing a state in which the pressing rib 21 of the door 20 presses the locking members 112L and 112R. Figure 10 111 is a cross-sectional view showing a state in which the top surface 20 d of the door 20 presses the restriction members 111L and 111R.

[0056] First, a procedure for detaching the fixing unit 80 from the supporting portion 90 of the moving unit 140 will be described. Figure 6A As shown, the user first moves the door 20 from the closed position to the open position. Here, a fixing locking member not shown is provided on the fixing unit 80, and the fixing locking member is engaged with a locked portion not shown provided in the device body 1A, so that the fixing unit 80 is maintained in the first position. That is, in a state in which the fixing locking member of the fixing unit 80 is engaged with the locked portion of the device body 1A, the upward movement of the movable unit 140 from the accommodated position to the supporting position is restricted. For example, in the case of implementing a jam removal in the conveying path 1c or the duplex conveying path 20a, the user can Figure 6A Perform jam removal in the state of .

[0057] like Figure 6A 、 6B As shown in Figures 7A and 7B, the restricting member 111L and the locking member 112L are provided on one side (the left side) of the moving unit 140 in the longitudinal direction LD. The restricting member 111R, the locking member 112R, and the release lever 113 are provided on the other side (the right side) of the moving unit 140 in the longitudinal direction LD. The restricting members 111L and 111R, the locking members 112L and 112R, and the release lever 113 are supported so as to be pivotable relative to the shaft member 92. In other words, the restricting members 111L and 111R, the locking members 112L and 112R, and the release lever 113 are pivotable relative to each other about the shaft member 92 serving as the same axis.

[0058] Restricting members 111L and 111R each have a shape that covers a corresponding one of locking members 112L and 112R. Engaging claws 112La and 112Ra, which are elastically deformable under a predetermined force, are provided on the side surfaces of locking members 112L and 112R, respectively, which serve as disassembly restricting portions. Restricting members 111L and 111R are provided with protrusions 111La and 111Ra, respectively, over which engaging claws 112La and 112Ra can pass under a predetermined force. When engaging claws 112La and 112Ra engage with protrusions 111La and 111Ra, respectively, locking members 112L and 112R pivot integrally with restricting members 111L and 111R, respectively.

[0059] At the same time, while the engagement between the engagement claws 112La and 112Ra and the protrusions 111La and 111Ra is canceled, the locking members 112L and 112R can be relatively pivoted with respect to the restricting members 111L and 111R by the user's pivoting operation of the locking members 112L and 112R. The claw portions 115L and 115R are provided on the distal end portions of the restricting members 111L and 111R, respectively. Figure 7A 、 7B9. In addition, recesses 116L and 116R capable of engaging with the claw portions 115L and 115R are provided on the fixing unit 80, as shown in FIG. Figure 2 The claw portions 115L and 115R engage with the recesses 116L and 116R, thereby restricting upward movement of the fixing unit 80. That is, in a state where the claw portions 115L and 115R engage with the recesses 116L and 116R, the fixing unit 80 supported by the supporting portion 90 is restricted from being removed from the supporting portion 90.

[0060] The restricting members 111L and 111R are movable to a disassembly restricting position in which the claw portions 115L and 115R engage with the recessed portions 116L and 116R, and a disassembly allowing position in which the claw portions 115L and 115R are separated from the recessed portions 116L and 116R. That is, the restricting members 111L and 111R restrict disassembly of the fixing unit 80 from the supporting portion 90 at the disassembly restricting position, and allow disassembly of the fixing unit 80 from the supporting portion 90 at the disassembly allowing position.

[0061] In addition, if Figure 7A As shown, the restricting member 111L is held in an upright position by a restricting spring 114. For example, the restricting spring 114, which serves as an urging member, is composed of a torsion coil spring having a coil portion supported by the shaft member 92, one end engaged with the restricting member 111L, and the other end engaged with the metal frame 91.

[0062] The limiting member 111R is also similarly maintained in an upright position by a spring not shown. It should be noted that in the present embodiment, the limiting members 111L and 111R are configured to pivot independently of each other around the shaft member 92, but the construction is not limited to this. For example, the limiting members 111L and 111R can be configured to pivot integrally with each other, and in this case, only one limiting spring is required. The position in which no external force is applied to the limiting members 111L and 111R and the limiting members 111L and 111R are maintained in an upright position by the limiting spring 114 will be referred to as the original position. In the state in which the limiting members 111L and 111R are positioned in the original position and the engaging claws 112La and 112Ra are engaged with the protrusions 111La and 111Ra, the locking members 112L and 112R are positioned at the disassembly limiting position.

[0063] The restricting members 111L and 111R positioned at the home position are opposed to the fixing unit 80 placed on the supporting portion 90 in the cross direction ID, and restrict the fixing unit 80 from falling from the supporting portion 90. More specifically, the restricting members 111L and 111R as the restricting portions restrict the fixing unit 80 from falling from the supporting portion 90 toward the door 20 positioned at the open position.

[0064] like Figure 4 As shown, when the movable unit 140 is positioned at the supporting position, the restricting members 111L and 111R protrude higher than the upper surface 1g of the apparatus main body 1A. That is, when the movable unit 140 is positioned at the supporting position, at least a portion of the restricting members 111L and 111R is positioned above the upper surface 1g of the apparatus main body 1A. Furthermore, when the movable unit 140 is positioned at the supporting position, at least a portion of the restricting members 111L and 111R is positioned above the upper end 84a of the pressure roller 84. By configuring the restricting members 111L and 111R in this manner, even when a strong force is applied to the fixing unit 80, the fixing unit 80 can be restricted from falling off the supporting portion 90.

[0065] In addition, since the restricting members 111L and 111R protrude higher than the upper surface 1g of the apparatus body 1A, the user can intuitively recognize the position where the fixing unit 80 is attached when the fixing unit 80 is attached to the supporting portion 90, as described below. Therefore, the attachability and detachability of the fixing unit 80 and the usability can be improved.

[0066] like Figure 7B As shown, the release lever 113 is configured to be pivotable in the up-down direction by the user, and the user can move the above-mentioned fixing lock member (not shown) of the fixing unit 80 by operating the release lever 113. The fixing lock member is supported by a frame member of the fixing unit 80 so as to be movable between a restricting position and a allowing position and is urged toward the restricting position by an urging member (not shown).

[0067] In the restricting position, the fixing lock member can engage with the locked portion of the apparatus body 1A to restrict the movement of the fixing unit 80 from the first position to the second position, that is, the upward movement of the moving unit 140. In the allowing position, the engagement between the fixing lock member and the locked portion is canceled, thereby allowing the movement of the fixing unit 80 from the first position to the second position. When the user operates the release lever 113, the fixing lock member moves from the restricting position to the allowing position.

[0068] like Figure 6A and Figure 6B As shown, when the door 20 is opened from the closed position to the open position and the user operates the release lever 113, the fixing locking member of the fixing unit 80 moves from the restricting position to the allowing position, thereby starting the upward movement of the moving unit 140. As a result, the moving unit 140 moves upward from the accommodated position to the supporting position, and the fixing unit 80 moves upward from the first position to the second position.

[0069] Next, if Figure 8As shown, the user pivots the locking members 112L and 112R from the removal restricting position to the removal allowing position. As a result, the claw portions 115L and 115R of the locking members 112L and 112R engage with the recesses 116L and 116R of the fixing unit 80 (see FIG. Figure 2 ) is separated, so that the fixing unit 80 can be removed from the supporting portion 90.

[0070] In this state, the user can lift the gripping portions 117L and 117R provided on the upper surface of the fixing unit 80, thereby detaching the fixing unit 80 from the supporting portion 90. The fixing unit 80 is placed only on the metal frame 91 and the shaft member 92 of the supporting portion 90, and thus the fixing unit 80 can be easily detached from the supporting portion 90 by only lifting the fixing unit 80.

[0071] It should be noted that in a state where the moving unit 140 is moved upward to the supporting position, the grip portions 117L and 117R are positioned above the upper surface 1g of the apparatus body 1A. Therefore, the user can easily lift the fixing unit 80, thereby improving operability.

[0072] In a state where the fixing unit 80 is detached from the supporting portion 90, as shown in FIG. Figure 2 As shown, the support portion 90 can be visually recognized. In addition, the metal frame 91 and the shaft member 92 of the support portion 90 extend approximately the entire length of the fixing unit 80 in the longitudinal direction LD, and the user can intuitively recognize the position where the fixing unit 80 is placed. In addition, in a state where the fixing unit 80 is detached from the support portion 90, the moving unit 140 remains at the supporting position, so that the support portion 90 is positioned near the opening portion 9, and the visual recognition of the support portion 90 can be improved.

[0073] For example, when the consumable parts of the fixing unit 80 have expired, the fixing unit 80 is replaced. When attaching a brand new fixing unit 80 to the supporting portion 90, the user moves the fixing unit 80 toward the supporting portion 90 by hooking their fingers on the gripping portions 117L and 117R. At this time, if the locking members 112L and 112R are positioned at the detachment restricting portion, the lower surface of the fixing unit 80 contacts the locking members 112L and 112R.

[0074] In this embodiment, the locking members 112L and 112R each have Figure 9 The tapered surface 115a shown in FIG. 115a is pressed against the tapered surface 115a, and the locking members 112L and 112R are moved to the removal allowing position by the fixing unit 80. Therefore, the fixing unit 80 can be attached to the supporting portion 90 even in a state where the locking members 112L and 112R are positioned at the removal restricting position.

[0075] It should be noted that in the present embodiment, the engagement claws 112La and 112Ra and the protrusions 111La and 111Ra are engaged with each other, so the locking members 112L and 112R can be held at the disassembly restricting positions.

[0076] The user then pushes down on the fixing unit 80 or the moving unit 140, causing the fixing unit 80 to move downward until the movement of the fixing unit 80 is restricted by the locked portion. With the fixing locking member provided on the fixing unit 80 engaged with the locked portion of the apparatus body 1A, the fixing unit 80 is positioned at the first position. Thus, the user can intuitively determine the position at which the fixing unit 80 should be pushed down. The user then closes the door 20, completing the replacement of the fixing unit 80.

[0077] It should be noted that if Figure 9 As shown, the pressing rib 21 is provided on the surface of the door 20 that is opposite to the fixing unit 80. The pressing rib 21 is provided at each position corresponding to the locking member 112L or 112R provided on the right and left sides. For example, the case where the user closes the door 20 while the engagement between the engagement claws 112La and 112Ra and the protrusions 111La and 111Ra is canceled and the locking members 112L and 112R are still positioned at the removal restriction position will be considered.

[0078] At this time, the pressing ribs 21 provided on the left and right sides of the door 20 immediately before reaching the closed position press the locking members 112L and 112R. Then, when the door 20 reaches the closed position, the locking members 112L and 112R are pressed by the pressing ribs 21 and pivot to the removal restriction position, thereby locking the fixing unit 80 by the locking members 112L and 112R. Therefore, the fixing unit 80 is securely locked to the supporting portion 90, and the fixing unit 80 can be securely maintained in the first position in a state where the door 20 is closed.

[0079] In addition, if Figure 10 As shown, the following will consider a case where the door 20 is closed from the open position to the closed position while the movable unit 140 is positioned in the support position and the fixing unit 80 is removed from the support portion 90 of the movable unit 140. The restricting members 111L and 111R are supported so as to be pivotable about the shaft member 92, and are therefore pressed toward the discharge tray 1f by the door 20 as the door 20 moves from the open position to the closed position. Therefore, the restricting members 111L and 111R pivot about the shaft member 92. Therefore, breakage of the restricting members 111L and 111R can be suppressed. Furthermore, the door 20 can be moved to the closed position even when the fixing unit 80 is not placed on the support portion 90 of the movable unit 140.

[0080] Jam removal in the fixing unit

[0081] Next, we will refer to Figure 11 A method for removing the sheet S jammed in the fixing unit 80 is described. Figure 11 80 is a perspective view showing how jam removal of the sheet S held in the fixing unit 80 is performed.

[0082] like Figure 11 As shown, when removing the sheet S held in the fixing nip of the fixing unit 80, the fixing unit 80 is moved upward to the second position in the same manner as described above for removing the fixing unit 80. The sheet S held in the fixing nip can then be pulled out to the front, either downward or upward, as desired. To pull the sheet S downward, the user pulls the sheet S downward while the fixing unit 80 is still placed on the support portion 90.

[0083] In contrast, in the case of pulling the sheet S upward to the front side, the user first opens the cover 118, which is openable and closable and is provided on the fixing unit 80. Therefore, the user can access the vicinity of the fixing nip of the fixing unit 80. When the user pulls the sheet S upward to the front side, a force acts on the fixing unit 80 upward in the vertical direction VD and forward in the cross direction ID through the sheet S.

[0084] However, the fixing unit 80 is positioned in the cross direction ID by the restricting members 111L and 111R, and is positioned in the vertical direction VD by the supporting portion 90 and the claw portions 115L and 115R of the locking members 112L and 112R. Therefore, even in the case of performing jam removal of the sheet S clamped in the fixing unit 80, the restricting members 111L and 111R and the locking members 112L and 112R restrict the fixing unit 80 from falling from the supporting portion 90 toward the door 20 positioned in the open position.

[0085] It should be noted that, as referenced Figure 9 As described above, the fixing unit 80 is locked by the restricting members 111L and 111R by closing the door 20. Therefore, it is possible to suppress the situation where the restricting members 111L and 111R are separated from the fixing unit 80 during the jam removal of the sheet S held in the fixing unit 80. Furthermore, the jam removal described above can be performed not only when the fixing unit 80 is positioned in the second position, but also when the fixing unit 80 is positioned in the first position. In this case as well, the fixing unit 80 is restricted from falling from the support portion 90 toward the door 20 positioned in the open position by the restricting members 111L and 111R and the locking members 112L and 112R.

[0086] In addition, in this embodiment, the fixing unit 80 is moved upward by the moving unit 140 and is thus exposed to the upper side through the opening portion 9. Since the upward movement of the fixing unit 80 is carried out in a substantially vertical direction toward the upper side, the movement distance is shorter than, for example, the case where the fixing unit 80 is moved upward by pivoting. Therefore, the time required to replace the fixing unit 80 or remove a jam can be shortened, thereby improving the attachability and detachability of the fixing unit 80 and the jam removal performance.

[0087] Furthermore, the restricting members 111L and 111R are positioned further outward in the longitudinal direction LD than the cover 118 of the fixing unit 80. Therefore, the restricting members 111L and 111R can be designed without regard for restrictions on the transport path of the sheet S, thereby improving design flexibility. For example, since the restricting members 111L and 111R can be brought closer to the fixing unit 80, displacement of the fixing unit 80 can be restricted. Furthermore, the opening angle of the cover 118 can be increased when the fixing unit 80 is placed on the support portion 90, thereby improving the operability of removing a sheet S stuck in the fixing nip.

[0088] Furthermore, the restricting member 111R, serving as the second restricting member, is positioned at a different position in the longitudinal direction LD than the restricting member 111L, serving as the first restricting member. More specifically, the distance D1 between the restricting members 111L and 111R is greater than the width of the largest sheet that can be used in the imaging apparatus 1. In other words, in the longitudinal direction LD, the restricting members 111L and 111R are positioned outside the area through which sheets can pass. Consequently, the restricting members 111L and 111R do not interfere with a sheet S pulled by a user, thereby improving jam removability.

[0089] As described above, the restricting members 111L and 111R and the locking members 112L and 112R can suppress the fixing unit 80 positioned at the second position from falling off the supporting portion 90. Therefore, it is possible to reduce breakage of the fixing unit 80. In addition, since the fixing unit 80 can be suppressed from falling off the supporting portion 90 even when the jammed sheet S held in the fixing unit 80 is pulled, the jam removability can be improved.

[0090] Other embodiments

[0091] It should be noted that although the moving unit 140 is provided with a pair of restricting members 111L and 111R in the above embodiment, the configuration is not limited thereto. For example, the moving unit 140 may be provided with one restricting member or three or more restricting members.

[0092] In addition, although the moving unit 140 is provided with a pair of locking members 112L and 112R in the above embodiment, the configuration is not limited thereto. For example, the moving unit 140 may be provided with one locking member or three or more locking members.

[0093] In addition, although the fixing unit 80 is restrained from falling off the supporting portion 90 by the restraining members 111L and 111R and the locking members 112L and 112R in the above embodiment, the configuration is not limited thereto. For example, the locking members 112L and 112R may be omitted, and the fixing unit 80 may be restrained from falling off the supporting portion 90 by the restraining members 111L and 111R. Alternatively, the restraining members 111L and 111R may be omitted, and the fixing unit 80 may be restrained from falling off the supporting portion 90 by the locking members 112L and 112R.

[0094] In addition, although the restricting members 111L and 111R and the locking members 112L and 112R are pivotally supported by the same shaft member 92 in the above embodiment, the configuration is not limited thereto. For example, the locking members 112L and 112R may be pivotally supported by the restricting members 111L and 111R, respectively.

[0095] In addition, although the second position of the fixing unit 80 is located above the first position in the above embodiment, the configuration is not limited thereto. For example, the fixing unit 80 may be moved horizontally from the first position to the second position, or may be moved diagonally downward from the first position to the second position.

[0096] Furthermore, while the lifting portion 100 includes a linkage mechanism comprised of multiple arms in the above-described embodiment, the configuration is not limited thereto. For example, the lifting portion 100 may include a rack portion, and the support portion 90 or 190 may be configured to be raised and lowered via engagement between the rack portion and a pinion portion provided on the support portion 90 or 190. Alternatively, the support portion 90 or 190 may be provided with a pinion, and the lifting portion 100 may be provided with a rack member. As described above, the configuration of the lifting portion 100 is not limited.

[0097] In addition, although the fixing unit 80 includes the heating roller 83 and the pressure roller 84 in the above embodiment, the configuration is not limited thereto. For example, a heating unit including a heater (e.g., a ceramic heater) and a fixing film heated by the heater may be used in place of the heating roller 83. Alternatively, a fixing belt including a heat-generating layer that generates heat by induction heating may be used in place of the heating roller 83.

[0098] In addition, although the photosensitive drum 61, charging roller 62, and developing roller 71 are provided in each of the process cartridges (PY to PK) in the above embodiment, the configuration is not limited thereto. That is, the photosensitive drum 61, charging roller 62, and developing roller 71 may be provided in the process cartridge or the tray 51.

[0099] In addition, although the door 20 is provided so as to be pivotable about the pivot shaft 20b in the above embodiment, the configuration is not limited thereto. For example, a cover that can slide or be detached relative to the apparatus body 1A may be provided instead of the door 20.

[0100] 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 following claims are to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming apparatus configured to form a toner image on a sheet, the image forming apparatus comprising: A device body, wherein the device body is provided with an opening portion; an opening and closing member supported so as to be openable and closable relative to the device main body between a closed position in which the opening member covers the opening portion and an open position in which the opening member opens the opening portion; a fixing unit supported so as to be attachable to and detachable from the apparatus main body via the opening portion and configured to fix the toner image to the sheet by applying heat and pressure to the sheet; and a moving unit provided in the apparatus main body and configured to move the fixing unit from a first position toward a second position different from the first position, wherein, when the opening and closing member is positioned at the closed position, movement of the fixing unit from the first position to the second position is restricted, and when the opening and closing member is positioned at the open position, movement of the fixing unit from the first position to the second position is permitted, and Wherein, the mobile unit includes: a supporting portion configured to support the fixing unit positioned at the second position; and a restricting portion configured to restrict the fixing unit supported by the supporting portion from falling off the supporting portion.

2. The imaging device according to claim 1, wherein The supporting portion extends in a longitudinal direction of the fixing unit and supports the fixing unit from below.

3. The imaging device according to claim 1, wherein When viewed along the longitudinal direction of the fixing unit, the fixing unit positioned at the first position does not overlap with the opening and closing member positioned at the closed position, and wherein, when viewed along the longitudinal direction of the fixing unit, at least a portion of the second position of the fixing unit overlaps with the opening and closing member positioned at the closed position.

4. The imaging device according to claim 1, wherein The second position is located above the first position.

5. The imaging device according to claim 1, wherein The restricting portion restricts the fixing unit from falling from the supporting portion toward the opening and closing member positioned at the open position.

6. The imaging device according to claim 1, wherein The restrictions include: a first restricting member opposed to the fixing unit in a crossing direction intersecting both the longitudinal direction and the vertical direction of the fixing unit; and A second restricting member is provided at a position different from that of the first restricting member in the longitudinal direction, the second restricting member being opposed to the fixing unit in the intersecting direction.

7. The imaging device according to claim 6, wherein A distance between the first and second restricting members in the longitudinal direction is greater than a width of a sheet of a maximum size usable in the image forming apparatus.

8. The imaging device according to claim 1, wherein The fixing unit includes a cover that can be opened and closed, and The restricting portion is provided at an outer side than the cover in a longitudinal direction of the fixing unit.

9. The imaging device according to claim 1, wherein The restricting portion is pivotally supported by the supporting portion.

10. The imaging device according to claim 9, wherein The movable unit is movable between an accommodated position at which the movable unit is positioned when the opening and closing member is positioned at the closed position and a supporting position at which the movable unit can support the fixing unit positioned at the second position, and wherein, when the opening and closing member moves from the open position to the closed position in a state in which the moving unit is positioned at the supporting position and the fixing unit is detached from the supporting portion of the moving unit, the restricting portion pivots by being pressed by the opening and closing member.

11. An imaging device according to claim 9, further comprising a pushing member configured to push the limiting portion to a position opposite to the fixing unit positioned at the second position and at which the limiting portion limits the fixing unit supported by the supporting portion from falling from the supporting portion.

12. The imaging device according to claim 1, wherein The movable unit is movable between an accommodated position at which the movable unit is positioned when the opening and closing member is positioned at the closed position and a supporting position at which the movable unit can support the fixing unit positioned at the second position, and Wherein, when the moving unit is positioned at the supporting position, at least a portion of the restricting portion is positioned above an upper surface of the device body.

13. The imaging device according to claim 1, wherein The movable unit is movable between an accommodated position, where the movable unit is positioned when the opening and closing member is positioned at the closed position, and a supporting position, where the movable unit can support the fixing unit positioned at the second position. Wherein, the fixing unit comprises: a heating unit configured to heat the toner image on the sheet; and a pressure roller configured to nip the sheet together with the heating unit, and Here, at least a portion of the restriction portion is positioned above an upper end of the pressing roller in a state where the moving unit is positioned at the supporting position.

14. The imaging device according to claim 1, wherein The moving unit includes a detachment restricting portion configured to restrict detachment of the fixing unit from the supporting portion by engaging with the fixing unit supported by the supporting portion.

15. The imaging device according to claim 14, wherein The disassembly limiting portion is capable of moving between a disassembly limiting position and a disassembly allowing position, wherein at the disassembly limiting position, the disassembly limiting portion limits the disassembly of the fixing unit from the supporting portion by engaging with the fixing unit, and at the disassembly allowing position, the disassembly limiting portion is separated from the fixing unit to allow the fixing unit to be disassembled from the supporting portion.

16. The imaging device according to claim 15, wherein In a case where the opening and closing member moves from the open position to the closed position, the disassembly restricting portion moves to the disassembly restricting position by being pressed by the opening and closing member.

17. The imaging device according to claim 14, wherein The disassembly restricting portion is pivotally supported by the supporting portion.

18. The imaging device according to claim 14, wherein The restricting portion and the disassembly restricting portion are supported so as to be pivotable about the same shaft member.

19. The image forming apparatus according to any one of claims 1 to 18, further comprising an image forming portion configured to form a toner image on a sheet, in, The image forming portion is configured to be attachable to and detachable from the apparatus main body via the opening portion in a state in which the fixing unit has been moved to the second position by the moving unit.

Images