Image-forming device

Abstract

To provide an image-forming device that has a configuration for changing a clamping pressure in a fixing nib in linking with a door and can be miniaturized.SOLUTION: An image-forming device includes: a casing having a first side plate and a second side plate disposed side by side in a predetermined direction; a fixing device for fixing a toner image transferred to a sheet to the sheet by applying heat and pressure in a fixing nip; a clamping pressure changing section for changing a clamping pressure for clamping the sheet in the fixing nip; a door; and a connection section for connecting the door and the clamping pressure changing section. The first side plate has an opening. The connection section includes a first part disposed in a side opposite to the second side plate relative to the first side plate in a predetermined direction and a second part disposed in the same side as the second side plate relative to the first side plate in a predetermined direction, and is disposed so as to penetrate the opening.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] According to Patent Document 1, an image forming apparatus is proposed that includes a photosensitive drum that carries a toner image, a transfer roller that transfers the toner image carried on the photosensitive drum to a sheet, and a fixing device that fixes the toner image transferred to the sheet by the transfer roller to the sheet. The fixing device includes a heating unit that includes a heater, and a pressure roller that forms a fixing nip together with the heating unit. The heating unit is biased against the pressure roller by a pressure spring.

[0003] The image forming apparatus is also provided with an openable door, a contact / separation mechanism that releases the pressure applied by the pressure spring at the fixing nip, and a link mechanism that operates the contact / separation mechanism in conjunction with the door opening operation, thereby making it possible to easily remove a sheet that has jammed at the fixing nip. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-243851 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the link mechanism described in Patent Document 1 is disposed outside the side plate of the image forming apparatus, which causes the image forming apparatus to become large in size.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an image forming apparatus that can be made compact while having a configuration in which the clamping pressure in the fixing nip is changed in conjunction with a door. [Means for solving the problem]

[0007] The present invention relates to an image forming apparatus, the image forming apparatus comprising: a housing having a first side plate and a second side plate arranged side by side in a predetermined direction; a cartridge having an image carrier carrying a toner image, the cartridge being attached to the housing between the first side plate and the second side plate and removable from the housing; a transfer section that transfers the toner image carried on the image carrier to a sheet; a heating unit having a heater; and a pressure roller that forms a fixing nip together with the heating unit, the fixing device fixing the toner image transferred to the sheet to the sheet by applying heat and pressure in the fixing nip; a nip pressure changing section that changes the nip pressure with which the fixing device nip the sheet in the fixing nip; the cartridge is provided with a door that is movable between a closed position where it is closed and an open position where it is open relative to the housing, and that is moved from the closed position to the open position when the cartridge is removed from the housing; and a connecting portion that connects the door to the clamping pressure change portion and operates the clamping pressure change portion to reduce the clamping pressure when the door is moved from the closed position to the open position, wherein the first side plate has an opening, and the connecting portion has a first portion that is positioned on the opposite side of the first side plate to the second side plate in the specified direction, and a second portion that is positioned on the same side of the first side plate as the second side plate in the specified direction, and is arranged to penetrate the opening. Effect of the Invention

[0008] According to the present invention, it is possible to reduce the size of the image forming apparatus while having a configuration in which the clamping pressure in the fixing nip is changed in conjunction with the door. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall schematic view showing a printer according to a first embodiment. [Diagram 2] FIG. [Diagram 3](a) is an oblique view showing the fixing device and the clamping pressure change section, (b) is a cross-sectional view showing the first clamping pressure change unit when the cam is positioned in the separated position, and (c) is a cross-sectional view showing the first clamping pressure change unit when the cam is positioned in the abutment position. [Figure 4] FIG. [Diagram 5] FIG. 2A is a diagram showing the arrangement of camshafts according to the first embodiment, and FIG. 2B is a diagram showing the arrangement of camshafts according to a comparative example. [Figure 6] 4A is a side view showing the peripheral configuration of the link member when the door is in the closed position, and FIG. 4B is a side view showing the peripheral configuration of the link member when the door is in the open position. [Figure 7] 7A is a perspective view showing the peripheral configuration of a link member, and FIG. 7B is a cross-sectional view showing the cross section taken along line 7B-7B of FIG. 7A. [Figure 8] 5A is a diagram for explaining jam removal, FIG. 5B is a cross-sectional view showing a movement trajectory of a cartridge, and FIG. 5C is a cross-sectional view showing the positional relationship between a link member and the movement trajectory. [Figure 9] 13A is a cross-sectional view showing a printer according to a modified example with the door closed, and FIG. 13B is a cross-sectional view showing the printer with the door open. [Figure 10] 10A is a perspective view showing the peripheral configuration of a link member according to a second embodiment, FIG. 10B is a cross-sectional view showing the cross section taken along line 10B-10B in FIG. 10A, and FIG. 10C is a perspective view showing the link member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <First embodiment> [Overall structure] First, a first embodiment of the present invention will be described. A printer 100 as an image forming apparatus according to the first embodiment is an electrophotographic laser beam printer. As shown in FIG. 1, the printer 100 has a feeding section 1 for feeding a sheet S, and an image forming section 3 for forming an image on the sheet S. The printer 100 also has a fixing device 9 for fixing the image on the sheet, a triple discharge roller set 50 for discharging the sheet to a discharge tray 51, and a double-sided conveying section 52 for forming images on both sides of the sheet.

[0011] The image forming section 3 has a laser unit 6, a photosensitive drum 4 as an image carrier, a charging roller 5, a developing roller 7, and a transfer roller 8 as a transfer section. The photosensitive drum 4, the charging roller 5, the developing roller 7, etc. are assembled into a cartridge 34. The cartridge 34 is configured to be detachable from the printer main body 100A.

[0012] When an image formation command is output to the printer 100, an image formation process is started by the image forming section 3 based on image information input from an external computer or the like connected to the printer 100. A laser unit 6 as an exposure section irradiates a laser beam toward the photosensitive drum 4 based on the input image information. At this time, the photosensitive drum 4 is charged in advance by a charging roller 5, and an electrostatic latent image is formed on the photosensitive drum 4 by irradiating it with the laser beam. Thereafter, the electrostatic latent image is developed by a developing roller 7, and a toner image is formed on the photosensitive drum 4.

[0013] In parallel with the above-mentioned image forming operation, sheets S stacked under the printer 100 are fed by the feeding unit 1. For example, the sheets S are stacked in a cassette that can be pulled out and attached to the printer main body 100A. The sheets S include paper such as paper and envelopes, plastic films such as overhead projector sheets (OHP), cloth, etc.

[0014] The feeding section 1 has a feeding roller 1a that feeds the sheet S, and a separation roller pair 1b that separates the sheets S fed by the feeding roller 1a one by one. The sheet S fed by the feeding section 1 is transported to a registration roller pair 2. The registration roller pair 2 forms a loop in the sheet S to correct skew, and transports the sheet S toward a transfer nip N1 formed by a photosensitive drum 4 and a transfer roller 8 at a predetermined transport timing. A toner image formed on the photosensitive drum 4 is transferred to the sheet S at the transfer nip N1 by the application of a transfer bias from the transfer roller 8.

[0015] Furthermore, the sheet S that has passed through the transfer nip N1 is applied with heat and pressure by the fixing nip N2 of the fixing device 9, so that the toner image is fixed thereon, and the sheet S is transported toward the discharge triplet rollers 50. The discharge triplet rollers 50 have a discharge drive roller 50a, a discharge driven roller 50b, and a reverse driven roller 50c. The discharge drive roller 50a is driven by a motor (not shown), and the discharge driven roller 50b and the reverse driven roller 50c rotate following the discharge drive roller 50a. The discharge drive roller 50a and the discharge driven roller 50b form a discharge nip 12, and the discharge drive roller 50a and the reverse driven roller 50c form a reverse nip 13.

[0016] In the case of single-sided printing in which an image is formed on one side of the sheet S, the sheet S conveyed by the fixing device 9 is guided by a guide member 11 toward a discharge nip 12. The guide member 11 is configured to be movable by an actuator at any timing between a position indicated by a solid line in Fig. 1 and a position indicated by a dashed line. The sheet S is then discharged onto a discharge tray 51 by the discharge nip 12.

[0017] In the case of double-sided printing in which images are formed on both sides of the sheet S, the sheet S with an image formed on the first side is conveyed to the reversing nip 13 by the guide member 11. The discharge driving roller 50a rotates in the reverse direction after the rear end of the sheet S leaves the guide member 11. As a result, the sheet S is switched back by the reversing nip 13 and conveyed toward the double-sided conveying section 52. The sheet S conveyed to the double-sided conveying section 52 is guided by the reversing guide 14 to pass below the fixing device 9, and is conveyed again to the registration roller pair 2 by the conveying roller pair 15.

[0018] The conveying roller pair 15 can be switched between driving and stopping by a mechanism (not shown), and stops when there is another sheet at the registration roller pair 2, and is driven after the other sheet has passed through the registration roller pair 2. Then, an image is formed on the second side of the sheet S at the transfer nip N1, and the sheet S is discharged to the discharge tray 51 by the discharge nip 12.

[0019] [Fixing device] Next, the configuration of the fixing device 9 will be described in detail with reference to FIG. 2. As shown in FIG. 2, the fixing device 9 has a heating device 16 as a heating unit and a pressure roller 17. The heating device 16 has a film 18 that is flexible, rotatable, and cylindrically formed, a heater 19, a film guide member 20, a stay member 21, and flange members 22L and 22R. The film 18, the heater 19, the film guide member 20, the stay member 21, and the pressure roller 17 are long members in a width direction W (see FIG. 3(a)) perpendicular to the conveying direction of the sheet S. The width direction W is a direction along the rotation axis of the photosensitive drum 4 (see FIG. 1).

[0020] The inner circumferential surface of film 18 is supported by film guide member 20, which supports heater 19. Stay member 21 holds and reinforces film guide member 20, and flange members 22L, 22R are attached to both ends of stay member 21 in width direction W, which is a predetermined direction. Film 18 rotates relative to pressure roller 17 as pressure roller 17 is driven by a drive source (not shown).

[0021] When the flange members 22L, 22R are pressed by a clamping pressure changing section, which will be described later, the pressing force acting on the flange members 22L, 22R is transmitted from the flange members 22L, 22R to the film 18 via the stay member 21, the film guide member 20, and the heater 19. As a result, a fixing nip N2 is formed between the heating device 16 including the film 18 and the pressure roller 17, and the sheet S is conveyed while being clamped in the fixing nip N2. At this time, a predetermined clamping pressure and heat are applied to the toner image on the sheet S, and the toner image can be fixed to the sheet S.

[0022] [Clamping pressure change section] Next, the nip pressure changing section 60 will be described with reference to Fig. 3(a) to Fig. 4. As shown in Fig. 3(a), the nip pressure changing section 60 has a first nip pressure changing unit 61L arranged on one side of the fixing device 9 in the width direction W, and a second nip pressure changing unit 61R arranged on the other side of the fixing device 9 in the width direction W.

[0023] The fixing device 9 has a pair of fixing side plates 23L, 23R arranged side by side in the width direction W. As shown in Figures 3(a) to 3(c), the first clamping pressure changing unit 61L has a pressure plate 24L, a tension spring 25L, and a cam 26L. The pressure plate 24L is supported by the fixing side plate 23L so as to be rotatable about a rotation fulcrum 24A, and the tension spring 25L is stretched between the fixing side plate 23L and the pressure plate 24L.

[0024] That is, the pressure plate 24L has a pivot point 24A at one end and a force point 24B at the other end where the force is received from the tension spring 25L. The pressure plate 24L presses the flange member 22L by the biasing force of the tension spring 25L at a point of action 24C between the pivot point 24A and the force point 24B. In other words, the biasing force of the tension spring 25L is transmitted to the flange member 22L via the pressure plate 24L by utilizing the principle of leverage. As a result, one side of the heating device 16 including the flange member 22L in the width direction W is biased toward the pressure roller 17.

[0025] The cam 26L is attached rotatably relative to the fixing side plate 23L. The cam 26L can stop at least in two phases: a separated position shown in FIG. 3(b) and a contact position shown in FIG. 3(c). At the separated position, the cam 26L is separated from the pressure plate 24L. Therefore, when the cam 26L is located at the separated position, the pressure roller 17 is pressed by the heating device 16 as described above.

[0026] Meanwhile, the cam 26L contacts the pressure plate 24L at the contact point 24D at the abutment position. At this time, the pressure plate 24L is pushed up by the cam 26L against the biasing force of the tension spring 25L from the position shown in FIG. 3(b). Also, the flange member 22L moves in the direction of arrow E shown in FIG. 3(c), that is, in the direction away from the pressure roller 17, until it contacts the pressure plate 24 due to the reaction force of the pressure roller 17. As a result, the pressure applied to the pressure roller 17 by the heating device 16 is reduced, and the clamping pressure in the fixing nip N2 is reduced.

[0027] Incidentally, the second nip pressure changing unit 61R has a pressure plate 24R, a tension spring 25R, and a cam 26R (see FIG. 4) similar to the first nip pressure changing unit 61L, and has the same action as the first nip pressure changing unit 61L. That is, when the cam 26R is located at the separated position, the other side in the width direction W of the heating device 16 including the flange member 22R is urged toward the pressure roller 17 by the tension spring 25R and the pressure plate 24R. Also, when the cam 26R is located at the abutting position, the pressure applied by the heating device 16 to the pressure roller 17 is reduced, and the nip pressure in the fixing nip N2 is reduced.

[0028] 4, the cam 26L as the first cam of the first clamping pressure change unit 61L and the cam 26R as the second cam of the second clamping pressure change unit 61R are connected by a cam shaft 27 so that their phases are the same. The cam shaft 27 extends parallel to the width direction W. Therefore, by rotating any one of the cams 26L, 26R and the cam shaft 27 by an actuator (not shown), the first clamping pressure change unit 61L and the second clamping pressure change unit 61R can be operated simultaneously.

[0029] [Camshaft arrangement] Next, the arrangement of the camshaft 27 will be described with reference to Figs. 5(a) and 5(b). Fig. 5(a) is a diagram showing the arrangement of the camshaft 27 according to the present embodiment, and Fig. 5(b) is a diagram showing the arrangement of the camshaft 127 according to a comparative example. As shown in Fig. 5(b), the camshaft 127 according to the comparative example is arranged below the fixing nip N2 of the fixing device 9 in the vertical direction VD. In other words, the camshaft 127 is arranged on the same side as the pressure roller 17 with respect to the conveying path through which the sheet S conveyed by the fixing nip N2 passes. The double-sided conveying path 140 formed by the reversing guide 14 is provided to avoid the camshaft 127, and is therefore arranged further below the camshaft 127. This results in an increase in the size of the printer body.

[0030] On the other hand, the cam shaft 27 according to the present embodiment is disposed above the fixing nip N2 of the fixing device 9 in the vertical direction VD, as shown in Fig. 5(a). In other words, the cam shaft 27 is disposed on the same side as the heating device 16 with respect to the conveying path through which the sheet S conveyed by the fixing nip N2 passes. For this reason, the double-sided conveying path 140 formed by the reversing guide 14 can be disposed closer to the fixing device 9 than in the comparative example described in Fig. 5(b).

[0031] Therefore, for example, when the curvature R of the double-sided conveying path 140 in Figures 5(a) and 5(b) is the same, the printer body 100A can be made smaller in the present embodiment shown in Figure 5(a) than in the comparative example shown in Figure 5(b). Also, when the size of the printer body 100A is not reduced, the curvature R of the double-sided conveying path 140 can be increased, the conveying resistance between the sheet S and the reversing guide 14 can be reduced, and the sheet S can be conveyed stably.

[0032] [Door and link member configuration] Next, the configuration of the door 28 provided in the printer main body 100A and the link member 30 as a connecting portion will be described with reference to Figures 6(a) to 7(b). Figure 6(a) is a side view showing the peripheral configuration of the link member 30 when the door 28 is in the closed position, and Figure 6(b) is a side view showing the peripheral configuration of the link member 30 when the door 28 is in the open position. Figure 7(a) is a perspective view showing the peripheral configuration of the link member 30, and Figure 7(b) is a cross-sectional view showing the 7B-7B cross section of Figure 7(a).

[0033] As shown in FIG. 7(a), the printer main body 100A has a housing 70 including a left side plate 32L and a right side plate 32R arranged side by side in the width direction W, a top cover 29, and the like, and a door 28 supported so as to be openable and closable relative to the top cover 29 of the housing 70. The left side plate 32L is an example of a first side plate, and the right side plate 32R is an example of a second side plate. The left side plate 32L and the right side plate 32R extend along a plane perpendicular to the width direction W. The door 28 is provided on the front side of the top cover 29. In the following description, the downstream side in the conveying direction of the sheet discharged by the discharge nip 12 is the front side of the printer 100, and the width direction W is parallel to the left-right direction of the printer 100. A space SP is provided between the left side plate 32L and the right side plate 32R of the housing 70, and a cartridge 34 (see FIG. 1) is attached to the space SP.

[0034] As shown in Fig. 6(a), the door 28 is supported on the top cover 29 so as to be openable and closable about the rotation shaft 28C, and can move between a closed position shown in Fig. 6(a) and an open position shown in Fig. 6(b). The door 28 is closed relative to the housing 70 in the closed position, and is open relative to the housing 70 in the open position. When the door 28 is in the closed position, the cam 26L is in the separated position, and when the door 28 is in the open position, the cam 26L is in the abutting position. The door 28 is moved from the closed position to the open position when the cartridge 34 (see Fig. 1) is removed from the housing 70 or when a jam is removed from the printer main body 100A.

[0035] 6(a) and 6(b), the door 28 is provided with a shaft portion 28A at a position different from the rotation shaft 28C when viewed in the width direction W, and the cam 26L is provided with a shaft portion 26A at a position different from the cam shaft 27. The shaft portion 28A of the door 28 and the shaft portion 26A of the cam 26L are connected by a link member 30. More specifically, the link member 30 has a hook portion 30A at one end and a hook portion 30B at the other end. The hook portion 30A is rotatably connected to the shaft portion 28A, and the hook portion 30B is rotatably connected to the shaft portion 26A.

[0036] When the door 28 moves from the closed position to the open position, the shaft portion 28A moves toward the front, and accordingly, the link member 30 connected to the shaft portion 28A by the hook portion 30A also moves toward the front by being guided by the guide member 31. The guide member 31 is fixed to the left side plate 32L. Then, as the link member 30 moves toward the front, the cam 26L connected to the hook portion 30B by the shaft portion 26A rotates about the cam shaft 27. As a result, the cam 26L moves from the separated position to the abutting position.

[0037] Conversely, when the door 28 moves from the open position to the closed position, the link member 30 moves backward, and the cam 26L moves from the abutting position to the separated position. Note that, since the cam 26L and the cam 26R are connected by the cam shaft 27, the cam 26R also moves integrally with the cam 26L between the abutting position and the separated position.

[0038] In this way, the cams 26L, 26R rotate via the link member 30 in conjunction with the opening and closing operation of the door 28. As a result, the clamping pressure in the fixing nip N2 changes due to the action of the clamping pressure changing unit 60 described above. Specifically, when the door 28 is opened relative to the housing 70, the clamping pressure in the fixing nip N2 decreases, and when the door 28 is closed relative to the housing 70, the clamping pressure in the fixing nip N2 increases.

[0039] [Jam Clearance] Next, a jam processing for removing the sheet S stuck in the fixing nip N2 will be described with reference to Fig. 8(a). First, as shown in Fig. 8(a), a user opens the door 28. At this time, the above-mentioned link member 30 and the clamping pressure changing unit 60 decrease the clamping pressure of the fixing nip N2 in conjunction with the opening operation of the door 28.

[0040] The user then removes the cartridge 34 from the space SP in the housing 70 and removes the jammed sheet S. When the printer 100 is in operation, the cams 26L and 26R are in the separated position, so the clamping pressure in the fixing nip N2 is high. This is because a certain clamping pressure is necessary to fix the toner image to the sheet S. However, if the clamping pressure in the fixing nip N2 is high, the user must pull the sheet S with a large force when removing the jammed sheet S from the fixing nip N2, which reduces usability. Furthermore, in some cases, the sheet S may be torn.

[0041] However, in this embodiment, the clamping pressure of the fixing nip N2 is reduced in conjunction with the door 28 being opened when clearing the jam, so that the user can remove the sheet S from the fixing nip N2 with less force, and the jam can be cleared easily. After removing the sheet S from the housing 70, the user installs the cartridge 34 in the housing 70 and closes the door 28. This returns the clamping pressure of the fixing nip N2 to its original state, and the fixing device 9 becomes ready for printing.

[0042] [Link member placement] Next, the arrangement of the link member 30 will be described in detail with reference to Figures 7(a)(b) and 8(b)(c). As shown in Figures 7(a)(b), Figure 8(b) is a cross-sectional view showing the movement trajectory T of the cartridge 34, and Figure 8(c) is a cross-sectional view showing the positional relationship between the link member 30 and the movement trajectory T. Note that Figure 8(c) is a cross-sectional view showing the 7B-7B cross section of Figure 7(a). Note that Figures 7(a) and (b) show the housing 70 with the exterior cover on the side removed.

[0043] As shown in FIG. 7(a) and FIG. 7(b), the left side plate 32L is provided with a through hole 32A as an opening penetrating in the width direction W. The through hole 32A is disposed above the photosensitive drum 4 (see FIG. 1) in the vertical direction VD. The link member 30 is disposed so as to penetrate the through hole 32A. Therefore, the link member 30 has a first portion P1 disposed on the opposite side of the left side plate 32L from the right side plate 32R in the width direction W, and a second portion P2 disposed on the same side of the left side plate 32L as the right side plate 32R in the width direction W. The first portion P1 includes a hook portion 30A as a first engagement portion that engages with the shaft portion 28A of the door 28, and the second portion P2 includes a hook portion 30B as a second engagement portion that engages with the shaft portion 26A of the cam 26L. The link member 30 moves in the front-rear direction as the door 28 is opened and closed, but the through hole 32A has a play so that the link member 30 can move in the front-rear direction.

[0044] As shown in FIG. 7(a) and FIG. 8(b), the laser unit 6 is disposed inside the through hole 32A in the housing 70A. Here, the laser unit 6 is narrower in width in the width direction W than the cartridge 34. The cartridge 34 is positioned at the mounting position by, for example, engaging with the left side plate 32L and the right side plate 32R. That is, the cartridge 34 has a width substantially equal to the distance between the left side plate 32L and the right side plate 32R. Then, there is a space between the laser unit 6 and the left side plate 32L in the width direction W, and the second part P2 of the link member 30 is disposed in the space. In other words, at least a part of the second part P2 is disposed so as to overlap the laser unit 6 when viewed in the width direction W, and is disposed between the left side plate 32L and the laser unit 6 in the width direction W.

[0045] The link member 30 is configured to pass through the through hole 32A at approximately the center in the front-rear direction, but is not limited to this. For example, the link member 30 may pass through the through hole 32A at a position closer to the hook portion 30A, or may pass through the through hole 32A at a position closer to the hook portion 30B.

[0046] 8(c), the second portion P2 is disposed so as not to interfere with the movement trajectory T of the cartridge 34 when the cartridge 34 is attached to or detached from the housing 70. The first portion P1 is disposed outside the left side plate 32L and does not interfere with the cartridge 34. By disposing the laser unit 6, the second portion P2 of the link member 30, and the movement trajectory T in this manner, each member can be disposed compactly, and the printer 100 can be made smaller.

[0047] In addition, since the second portion P2 of the link member 30 is disposed inside the housing 70 relative to the left side plate 32L in the width direction W, there is ample space on the outer side of the left side plate 32L in the width direction W (opposite the right side plate 32R). As shown in FIG. 7(a), an electric board 33 is disposed on the outer side of the left side plate 32L in the width direction W, and the electric board 33 as a board extends to a position overlapping with the second portion P2 as seen in the width direction W. This allows a large area to be secured for the electric board 33. In addition, the electric board 33 is disposed so as not to interfere with the first portion P1 of the link member 30. The electric board 33 has, for example, a CPU that controls the image forming unit 3.

[0048] As described above, in this embodiment, the link member 30 is disposed so as to pass through the through hole 32A provided in the left side plate 32L. This allows the printer 100 to be made compact while still having a configuration in which the clamping pressure in the fixing nip N2 is changed in conjunction with the door 28.

[0049] <Modification> Next, a modified example of the first embodiment will be described with reference to Figures 9(a) and 9(b). Figure 9(a) is a cross-sectional view showing the printer 100B with the door 35 closed, and Figure 9(b) is a cross-sectional view showing the printer 100B with the door 35 open.

[0050] In the first embodiment described above, the door 28 constitutes a part of the top surface of the housing 70 when in the closed position. On the other hand, the door 35 according to the modified example constitutes a part of the side surface of the housing 70 when in the closed position. Also, the door 35 is configured to be rotatable in the front-rear direction around the rotation shaft 35A.

[0051] The door 35 is rotatably connected to a connection link 37 via a link shaft 37A. The connection link 37 is rotatably connected to a rotating link 38 via a link shaft 37B. The rotating link 38 has a groove 38B that engages with a shaft 36A provided on a link member 36 serving as a connecting portion, and is rotatable about a rotating shaft 38A. That is, the portion between the rotating shaft 35A and the link shaft 37A of the door 35, the connection link 37, and the portion between the link shaft 37B and the rotating shaft 38A of the rotating link 38 constitute a four-joint link mechanism.

[0052] With such a four-bar link mechanism, when the door 35 is opened or closed, the rotating link 38 rotates about the rotating shaft 38A, and the link member 36 engaged with the rotating link 38 moves in the front-rear direction. The link member 36 has the same function as the link member 30 in the first embodiment, and the clamping pressure in the fixing nip N2 changes as the link member 36 moves in the front-rear direction.

[0053] In this modified example, the four-bar link mechanism is used, but the present invention is not limited to this. For example, the link member 36 may be operated in conjunction with the door 35 using other mechanisms such as gears and pulleys. Of course, such link mechanisms and interlocking mechanisms are also applicable to the first embodiment.

[0054] <Second embodiment> Next, a second embodiment of the present invention will be described, which is the same as the first embodiment except that a fan 40 is added and the configuration of the link member is changed. Therefore, the same configuration as the first embodiment will be omitted from the illustrations or will be described with the same reference numerals in the drawings.

[0055] Fig. 10(a) is a perspective view showing the peripheral configuration of the link member 39, and Fig. 10(b) is a cross-sectional view showing the 10B-10B cross section of Fig. 10(a). Fig. 10(c) is a perspective view showing the link member 39. Note that Figs. 10(a) and 10(b) show the printer 100C with the exterior cover on the side of the housing 70 removed.

[0056] As shown in FIGS. 10(a) and 10(b), the printer 100C according to the second embodiment has a fan 40 and a duct 41. The fan 40 and the duct 41 are fixed to the left side plate 32L and are disposed on the opposite side of the left side plate 32L to the right side plate 32R in the width direction W. In the present embodiment, a link member 39 is disposed so as to penetrate the through hole 32A provided in the left side plate 32L, and the link member 39 as a connecting part has the same function as the link member 30 in the first embodiment. That is, the link member 39 connects the door 28 to the clamping pressure changing part 60 (see FIG. 3(a)) so that the clamping pressure in the fixing nip N2 changes in conjunction with the opening and closing of the door 28. As in the first embodiment, the link member 39 has a first part P11 disposed on the opposite side of the left side plate 32L to the right side plate 32R in the width direction W, and a second part P12 disposed on the same side of the left side plate 32L as the right side plate 32R in the width direction W.

[0057] Rotation of the fan 40 generates an airflow. The air sent from the fan 40 is guided toward the rear of the device by the duct 41 and discharged to the link member 39. As shown in FIG. 10(c), the link member 39 has a guide portion 39A that guides a portion of the air sent from the fan 40 toward the space SP inside the housing 70 via the through hole 32A. The guide portion 39A is provided at a position where the link member 39 passes through the through hole 32A, and has a groove shape in this embodiment. In other words, the guide portion 39A is formed to have a substantially U-shaped cross section.

[0058] As a result, a portion of the air discharged from the duct 41 is sent to the electric board 33 along the link member 39 and the left side plate 32L. Also, a portion of the air discharged from the duct 41 is guided by the guide portion 39A of the link member 39 through the through hole 32A into the space SP, i.e., the inside of the housing 70, as shown by the dashed arrow in FIG. 10(b). Therefore, both the electric board 33 and the inside of the housing 70 can be efficiently cooled by the single fan 40. Also, by providing the guide portion 39A to the link member 39, the link member 39 functions as an air guide member, so that the number of parts can be reduced, leading to cost reduction. In the second embodiment, the guide portion 39A is formed in a groove shape, but is not limited to this. For example, the guide portion 39A may be formed in a cylindrical shape or an L-shape.

[0059] <Other embodiments> In any of the above-described embodiments, the heater 19 is in direct contact with the film 18, but this is not limiting. For example, a sheet material having high thermal conductivity, such as an iron alloy or aluminum, may be provided between the heater 19 and the film 18.

[0060] In addition, in any of the above-described embodiments, the heating device 16 is biased toward the pressure roller 17, but this is not limiting. For example, the pressure roller 17 may be configured to be biased toward the heating device 16, and even in this case, the clamping pressure in the fixing nip N2 may be changed by the clamping pressure changing unit 60.

[0061] Furthermore, although the heating device 16 is configured to heat the film 18, the present invention is not limited to this. For example, the heating device 16 may be configured as a heating roller incorporating the heater 19. Furthermore, various types of heaters such as a ceramic heater, a carbon heater, or a halogen heater can be used as the heater 19. Furthermore, the heating device 16 may be configured to heat the heat generating layer of the belt by electromagnetic induction heating.

[0062] In addition, in all of the above-described embodiments, the link members 30, 36, 39 are provided on the left side plate 32L, but this is not limiting. For example, the link members 30, 36, 39 may be provided on the right side plate 32R. In this case, a through hole through which the link members 30, 36, 39 pass is provided in the right side plate 32R. Also, the link members 30, 36, 39 may be provided on both the left side plate 32L and the right side plate 32R.

[0063] In addition, in any of the above-described embodiments, the link member 30, 36, 39 is configured from one member, but this is not limiting. For example, the link member 30, 36, 39 may be configured from a plurality of members.

[0064] In addition, in any of the embodiments described above, the through hole 32A has a hole shape, but is not limited to this. For example, instead of the through hole 32A, a notch may be provided in the left side plate 32L.

[0065] In addition, in any of the above-described embodiments, the nip pressure changing unit 60 changes the nip pressure in a state where the heating device 16 and the pressure roller 17 are in contact with each other, but the present invention is not limited to this. For example, the nip pressure changing unit 60 may be configured so that the heating device 16 and the pressure roller 17 are separated from each other when the door 28 is opened. Note that, in a state where the heating device 16 and the pressure roller 17 are separated from each other, the nip pressure in the fixing nip N2 is set to 0.

[0066] The disclosure of the present embodiment also includes the following configuration examples and method examples. (Configuration 1) a housing having a first side plate and a second side plate arranged side by side in a predetermined direction; a cartridge having an image carrier that carries a toner image, the cartridge being attached to the housing between the first side plate and the second side plate and being removable from the housing; a transfer section for transferring the toner image carried on the image carrier onto a sheet; a fixing device including a heating unit having a heater and a pressure roller forming a fixing nip together with the heating unit, and fixing a toner image transferred onto a sheet onto the sheet by applying heat and pressure in the fixing nip; a nip pressure changing section that changes a nip pressure with which the fixing device nip a sheet in the fixing nip; a door that is movable between a closed position in which the door is closed relative to the housing and an open position in which the door is open relative to the housing, and that is moved from the closed position to the open position when the cartridge is removed from the housing; a connecting portion that connects the door and the clamping pressure change portion and operates the clamping pressure change portion so as to reduce the clamping pressure when the door is moved from the closed position to the open position, The first side plate has an opening, the connecting portion has a first portion disposed on an opposite side of the first side plate from the second side plate in the predetermined direction, and a second portion disposed on the same side as the second side plate with respect to the first side plate in the predetermined direction, and is disposed so as to penetrate the opening. 1. An image forming apparatus comprising: (Configuration 2) the second portion of the coupling portion is disposed so as not to interfere with a movement trajectory of the cartridge when the cartridge is attached to or detached from the housing. 2. The image forming apparatus according to claim 1, (Configuration 3) an exposure unit disposed between the first side plate and the second side plate and configured to expose the image carrier to light to form an electrostatic latent image on the image carrier; At least a part of the second portion is disposed so as to overlap the exposed portion when viewed in the predetermined direction, and is disposed between the first side plate and the exposed portion in the predetermined direction. 3. The image forming apparatus according to claim 1, wherein the first and second components are arranged in a same plane. (Configuration 4) the exposure unit has a width in the predetermined direction that is narrower than that of the cartridge; 4. The image forming apparatus according to claim 3, (Configuration 5) a substrate disposed on the opposite side of the first side plate from the second side plate in the predetermined direction and disposed so as not to interfere with the first portion of the connecting portion, 5. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction and a second direction. (Configuration 6) The substrate is disposed so as to overlap the second portion of the connecting portion when viewed in the predetermined direction. 6. The image forming apparatus according to configuration 5. (Configuration 7) The opening of the first side plate is disposed above the image carrier in the vertical direction. 7. The image forming apparatus according to any one of configurations 1 to 6. (Configuration 8) the clamping pressure change unit has a first cam arranged on one side of the fixing device in the predetermined direction, a second cam arranged on the other side of the fixing device in the predetermined direction, and a cam shaft connecting the first cam and the second cam, The cam shaft is disposed above the fixing nip in the vertical direction. 8. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction and a second direction. (Configuration 9) the first portion includes a first engagement portion that engages with the door, The second portion includes a second engagement portion that engages with the clamping pressure change portion. 9. The image forming apparatus according to any one of configurations 1 to 8. (Configuration 10) The door constitutes a part of the top surface of the housing in the closed position. 10. The image forming apparatus according to any one of configurations 1 to 9. (Configuration 11) The door constitutes a part of a side surface of the housing in the closed position. 10. The image forming apparatus according to any one of configurations 1 to 9. (Configuration 12) a fan that is disposed on an opposite side of the first side plate from the second side plate in the predetermined direction and that generates an airflow; The connecting portion has a guide portion that guides a portion of the air sent from the fan into the inside of the housing through the opening. 12. The image forming apparatus according to any one of configurations 1 to 11. (Configuration 13) The guide portion passes through the opening. 13. The image forming apparatus according to claim 12, (Configuration 14) The first side plate and the second side plate extend along a plane perpendicular to the predetermined direction. 14. The image forming apparatus according to any one of configurations 1 to 13. (Configuration 15) the predetermined direction is a direction along a rotation axis of the image carrier; 15. The image forming apparatus according to any one of configurations 1 to 14. [Explanation of symbols]

[0067] 4: Image carrier (photosensitive drum) / 6: Exposure section (laser unit) / 8: Transfer section (transfer roller) / 9: Fixing device / 16: Heating device (heating unit) / 17: Pressure roller / 19: Heater / 26L: First cam (cam) / 26R: Second cam (cam) / 27: Cam shaft / 28: Door / 30, 36, 39: Connection section (link member) / 30A: First engagement section (hook section) / 30 B: second engagement portion (hook portion) / 32A: opening (through hole) / 32L: first side plate (left side plate) / 32R: second side plate (right side plate) / 33: board (electrical board) / 34: cartridge / 39A: guide portion / 40: fan / 60: clamping pressure change portion / 70: housing / N2: fixing nip / P1, P11: first portion / P2, P12: second portion / T: movement trajectory / W: specified direction (width direction)

Claims

1. a housing having a first side plate and a second side plate arranged side by side in a predetermined direction; a cartridge having an image carrier that carries a toner image, the cartridge being attached to the housing between the first side plate and the second side plate and being removable from the housing; an exposure unit disposed between the first side plate and the second side plate, the exposure unit exposing the image carrier to light to form an electrostatic latent image on the image carrier; a transfer unit that transfers the toner image carried on the image carrier onto a sheet; a fixing device including a heating unit having a heater and a pressure roller that forms a fixing nip together with the heating unit, and that fixes the toner image transferred onto the sheet onto the sheet by applying heat and pressure at the fixing nip; a nip pressure changing unit that changes a nip pressure with which the fixing device nip-holds the sheet in the fixing nip; a door that is movable between a closed position where it is closed relative to the housing and an open position where it is open relative to the housing, and that is moved from the closed position to the open position when the cartridge is removed from the housing; a connecting unit that connects the door and the clamping pressure changing unit and operates the clamping pressure changing unit so as to reduce the clamping pressure when the door is moved from the closed position to the open position, the first side plate has an opening, the connecting portion has a first portion disposed on the opposite side of the first side plate from the second side plate in the predetermined direction, and a second portion disposed on the same side of the first side plate as the second side plate in the predetermined direction, and is disposed so as to pass through the opening; At least a part of the second portion is disposed so as to overlap the exposed portion when viewed in the predetermined direction, and is disposed between the first side plate and the exposed portion in the predetermined direction. An image forming apparatus characterized by:

2. the second portion of the coupling portion is positioned so as not to interfere with a movement trajectory of the cartridge when the cartridge is attached to or detached from the housing.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the exposure unit has a width in the predetermined direction that is narrower than that of the cartridge; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

4. a substrate disposed on the opposite side of the first side plate from the second side plate in the predetermined direction and disposed so as not to interfere with the first portion of the connecting portion; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. the substrate is disposed so as to overlap the second portion of the connecting portion when viewed in the predetermined direction.

5. The image forming apparatus according to claim 4.

6. the opening of the first side plate is disposed above the image carrier in the vertical direction; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. the clamping pressure changing unit includes a first cam disposed on one side of the fixing device in the predetermined direction, a second cam disposed on the other side of the fixing device in the predetermined direction, and a cam shaft connecting the first cam and the second cam, The cam shaft is disposed above the fixing nip in the vertical direction.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. the first portion includes a first engagement portion that engages with the door, The second portion includes a second engaging portion that engages with the clamping pressure changing portion.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. The door has an engaged portion that engages with the first engaging portion, The engaged portion moves along a horizontal direction when the door moves between the closed position and the open position.

9. The image forming apparatus according to claim 8,

10. The door forms a part of the top surface of the housing in the closed position.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

11. The door forms a part of a side surface of the housing in the closed position.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

12. a fan that is disposed on the opposite side of the first side plate from the second side plate in the predetermined direction and that generates an airflow; the connecting portion has a guide portion that guides a portion of the air sent from the fan into the inside of the housing through the opening.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

13. The guide portion passes through the opening.

13. The image forming apparatus according to claim 12.

14. The first side plate and the second side plate extend along a plane perpendicular to the predetermined direction.

13. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

15. the predetermined direction is a direction along the rotation axis of the image carrier; 13. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images