Image forming apparatus

Abstract

To provide an image forming apparatus capable of easily switching a pressure member from a pressure release state to a pressure state and from the pressure state to the pressure release state with respect to a fixing member without complicating the configuration of a fixing device.SOLUTION: The image forming apparatus 100 includes the first opening and closing member 110 that covers the fixing device 9 in the closed state and exposes the fixing device 9 in the open state, the fixing device 9 includes the second opening and closing member 120 that covers the component (92) in the fixing device body 901 in the closed state and exposes the component (92) in the open state, and when the first opening and closing member 110 is closed from the open state, the switching member 240 is operated to switch the pressing member 92 from the pressing release state to the pressing state. When the second opening and closing member 120 is opened from the closed state, the switching member 240 is operated to switch the pressing member 92 from the pressed state to the pressure released state.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to image forming apparatuses such as copiers, multifunction peripherals, printers, and facsimile machines. [Background technology]

[0002] 2. Description of the Related Art Image forming apparatuses that include a fixing device configured to be able to switch between a pressure-applied state and a pressure-release state of a pressure member against a rotatable fixing member using a switching member have been known (see, for example, Patent Document 1).

[0003] In more detail, Patent Document 1 describes a configuration in which an image forming apparatus has an opening / closing member (exterior cover unit) that covers the fixing device when closed and exposes the fixing device when open, and in which opening and closing the opening / closing member activates a switching member (pressure release arm) to place the pressure member in a pressure release state or a pressure release state, and in which switching from the pressure release state to the pressure release state and switching from the pressure release state are performed using a single opening / closing member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-19927 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional image forming devices, when performing each switch, an opening / closing member is engaged with a switching member, which makes the configuration of the opening / closing member and switching member for performing each switch complex, and ultimately makes the configuration of the fixing device complex.

[0006] Therefore, the present disclosure aims to provide an image forming apparatus that can easily switch the pressure member of a fixing member from a pressure-released state to a pressure-applied state and from a pressure-applied state to a pressure-released state without complicating the configuration of the fixing device. [Means for solving the problem]

[0007] In order to solve the above problem, the image forming apparatus of the present disclosure is an image forming apparatus including a fixing device configured to be able to switch between a pressurized state and a depressurized state of a pressure member against a rotatable fixing member using a switching member, and is characterized in that the image forming apparatus includes a first opening / closing member that covers the fixing device in a closed state and exposes the fixing device in an open state, and the fixing device includes a second opening / closing member that covers components inside the fixing device main body in a closed state and exposes the components in an open state, and when the first opening / closing member is closed from an open state, it activates the switching member to change the pressure member from the depressurized state to the pressurized state, and when the second opening / closing member is opened from a closed state, it activates the switching member to change the pressure member from the pressurized state to the depressurized state. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to easily switch the pressure member applied to the fixing member from a pressure-released state to a pressure-applied state and from a pressure-applied state to a pressure-released state without complicating the configuration of the fixing device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment of the present invention. [Figure 2] 2 is a perspective view of a fixing device in the image forming apparatus shown in FIG. [Figure 3] 3 is a cross-sectional view of the fixing device shown in FIG. 2 taken along line AA. [Figure 4] 3 is a cross-sectional view of the fixing device shown in FIG. 2 taken along line BB. [Figure 5] 2 is a perspective view showing a first opening / closing member in a closed state together with an open first opening / closing member in the image forming apparatus shown in FIG. 1. FIG. [Figure 6] 2 is a perspective view showing a state in which a first opening / closing member is removed from the image forming apparatus shown in FIG. 1. FIG. [Figure 7] 2 is a perspective view showing a switching mechanism in the fixing device shown in FIG. 1. FIG. [Figure 8] 2 is an exploded perspective view showing a right-side switching mechanism in the fixing device shown in FIG. 1. FIG. [Figure 9] 2 is an exploded perspective view showing a left-side switching mechanism in the fixing device shown in FIG. 1. FIG. [Figure 10] 1. FIG. 4 is a perspective view showing a state in which the second opening / closing member is opened and the pressure member is in a pressure-released state due to the action of the switching member in the fixing device shown in FIG. [Figure 11] 7 is an enlarged perspective view showing a sliding contact portion of the first opening / closing member shown in FIG. 6. FIG. [Figure 12] 10 is a cross-sectional view showing a first closing step in which the first opening / closing member is closed. FIG. [Figure 13] 10 is a cross-sectional view showing a second closing process in which the first opening / closing member is closed. FIG. [Figure 14] FIG. 10 is a cross-sectional view showing a third closing process in which the first opening / closing member is closed. [Figure 15] FIG. 10 is a cross-sectional view showing a fourth closing step in which the first opening / closing member is closed. [Figure 16] FIG. 10 is a cross-sectional view showing a fifth closing step in which the first opening / closing member is closed. [Figure 17] FIG. 10 is a cross-sectional view showing the unlocked state of the locking mechanism. [Figure 18] FIG. 4 is a cross-sectional view showing a locked state of the locking mechanism. [Figure 19] 10 is a cross-sectional view showing a first opening process in which the second opening / closing member is opened. FIG. [Figure 20] 10 is a cross-sectional view showing a second opening process in which the second opening / closing member is opened. FIG. [Figure 21] 10 is a cross-sectional view showing a third opening process in which the second opening / closing member is opened. FIG. [Figure 22] 10 is a cross-sectional view showing a second opening process in which the second opening / closing member is opened. FIG. [Figure 23] FIG. 10 is a cross-sectional view showing a fifth opening process in which the second opening / closing member is opened. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0011] (Image forming device) 1 is a cross-sectional view showing an image forming apparatus 100 according to the present embodiment. In the figure, the width direction is designated as X, the right side as X1, the left side as X2, the direction perpendicular to the width direction X as the depth direction Y, the front side as Y1, the back side as Y2, and the up-down direction perpendicular to the width direction X and the depth direction Y as Z, in the following description.

[0012] Image data handled by the image forming apparatus main body 101 of the image forming apparatus 100 corresponds to a color image using each of the colors black (K), cyan (C), magenta (M), and yellow (Y), or a monochrome image using a single color (e.g., black). For this reason, four photosensitive drums 1 (scanned body, image carrier), chargers 2, print heads 3, developing devices 4, primary transfer devices 5, and drum cleaning devices 6 are provided to form four types of toner images corresponding to each color, and four image stations Pa, Pb, Pc, and Pd are configured, each corresponding to black, cyan, magenta, and yellow. Note that the image forming apparatus 100 may also be a monochrome image forming apparatus.

[0013] In each of the image stations Pa, Pb, Pc, and Pd, the chargers 2-2 uniformly charge the surfaces 1a of the photosensitive drums 1-1, which are driven to rotate in a predetermined rotation direction R, to a predetermined potential. The print heads 3-3 expose the surfaces 1a of the photosensitive drums 1-1 to light, forming electrostatic latent images on the surfaces 1a of the photosensitive drums 1-1. The developing devices 4 develop the electrostatic latent images on the surfaces 1a of the photosensitive drums 1-1 to form toner images on the surfaces 1a of the photosensitive drums 1-1. This results in toner images of each color being formed on the surfaces 1a of the photosensitive drums 1-1. The drum cleaning devices 6-6 remove and collect residual toner from the surfaces 1a of the photosensitive drums 1-1. The primary transfer devices 5-5 sequentially transfer the toner images of each color on the surfaces 1a of the photosensitive drums 1-1, superimposed on one another, to an intermediate transfer belt 23, which is rotated by a drive roller 21 and a driven roller 22 of a belt drive device 20, forming color toner images on the intermediate transfer belt 23. The belt cleaning device 7 removes and collects residual toner from the intermediate transfer belt 23 .

[0014] A transfer nip portion TN is formed between the intermediate transfer belt 23 and a transfer roller 81 of the secondary transfer device 8. The transfer roller 81 of the secondary transfer device 8 sandwiches a sheet P, such as a recording paper, transported through the sheet transport path 11 in the transfer nip portion TN and transports it together with the intermediate transfer belt 23, while transferring the color toner image on the surface of the intermediate transfer belt 23 onto the sheet P. The fixing device 9 sandwiches the sheet P between a fixing member 91 (a fixing belt in this example) and a pressure member 92 (a pressure roller in this example) and applies heat and pressure to fix the color toner image on the sheet P.

[0015] In the image forming apparatus 100, a sheet P is pulled out from a paper feed unit 13 (paper feed cassette) by a pickup roller 12 and conveyed to a sheet conveying path 11, and then conveyed toward a discharge roller 14 via a secondary transfer device 8 and a fixing device 9. In the image forming apparatus 100, the sheet P conveyed to the discharge roller 14 is discharged to a discharge tray 15 by the discharge roller 14. Registration rollers 16 and the like are arranged on the sheet conveying path 11. The registration rollers 16 temporarily stop the sheet P and align the leading edge of the sheet P, and then start conveying the sheet P in accordance with the timing of the transfer of the toner image at a transfer nip portion TN between the intermediate transfer belt 23 and a transfer roller 81.

[0016] In FIG. 1, the paper feed unit 13 has two stages, but is not limited to this and may have one stage or three or more stages.

[0017] Furthermore, when forming an image on the back side of the sheet P in addition to the front side, the image forming apparatus 100 conveys the sheet P in the reverse direction from the discharge rollers 14 to the sheet inversion conveying path 17. The image forming apparatus 100 conveys the sheet P conveyed in the reverse direction toward the sheet inversion conveying path 17, inverts the sheet P by the sheet inversion conveying path 17, and guides the sheet P again to the registration rollers 16. The image forming apparatus 100 forms an image on the back side of the sheet P guided to the registration rollers 16 in the same manner as on the front side, and then conveys the sheet P to the discharge tray 15.

[0018] [Fixing device] Fig. 2 is a perspective view of the fixing device 9 in the image forming apparatus 100 shown in Fig. 1. Figs. 3 and 4 are cross-sectional views of the fixing device 9 shown in Fig. 2 taken along lines AA and BB, respectively.

[0019] The fixing device 9 further includes a support member 93, a fixing pad 94, a heat source 96, a reflecting member 97 (a reflecting plate in this example), a temperature detecting unit 98 (a thermopile in this example), a peeling plate 99 (see FIG. 3), and a thermostat 90. The support member 93, the fixing pad 94, the heat source 96, and the reflecting member 97 are provided inside the fixing belt (91).

[0020] The fixing belt (91) is an endless (annular) flexible belt that is rotatable about a rotation axis α1 that extends in a direction perpendicular to the conveying direction H of the sheet P (width direction X).

[0021] The fixing pad 94 is made of, for example, resin, and is formed in the shape of a long plate extending in the rotational axis direction W of the fixing belt (91). The fixing pad 94 includes a fixing pad main body 940 and a sliding sheet 941 provided on the surface of the fixing pad main body 940 that comes into sliding contact with the fixing belt (91).

[0022] The support member 93 is a member that supports the fixing pad 94. Both end portions of the support member 93 in the rotation axis direction W are fixed to the fixing device main body 901 (main body frame). A reflecting member 97 is provided on at least the surface of the support member 93 facing the heat source 96.

[0023] The heat source 96 is a member for heating the fixing belt (91) and extends in the direction W of the axis of rotation of the fixing belt (91). The heat source 96 may be, for example, a lamp heater such as a halogen lamp.

[0024] The pressure roller (92) is disposed at a position facing the fixing pad 94 with the fixing belt (91) sandwiched therebetween. The pressure roller (92) rotates about a rotation axis α2 parallel to the rotation axis α1 of the fixing belt (91) and extends parallel to the fixing belt (91). The pressure roller (92) presses the fixing belt (91) toward the fixing pad 94, thereby forming a fixing nip FN between the pressure roller (92) and the fixing belt (91).

[0025] A driving force from a driving source (not shown) such as a motor is transmitted to the pressure roller (92) via a drive transmission mechanism (not shown) such as a gear. The pressure roller (92) is driven to rotate by the driving force from the driving source. As the pressure roller (92) is driven to rotate, the fixing belt (91) is driven to rotate in a first rotation direction R1, which is opposite to the second rotation direction R2 of the pressure roller (92).

[0026] (About this embodiment) The image forming apparatus 100 includes a first opening / closing member 110 (a rear door in this example) (see FIG. 1), and the fixing device 9 includes a second opening / closing member 120 (a conveying paper guide in this example).

[0027] Fig. 5 is a perspective view showing the first opening / closing member 110 in a closed state in the image forming apparatus 100 shown in Fig. 1 together with the first opening / closing member 110 in an open state. Fig. 6 is a perspective view showing the image forming apparatus 100 shown in Fig. 1 with the first opening / closing member 110 removed.

[0028] Fig. 7 is a perspective view showing the switching mechanism 200 in the fixing device 9 shown in Fig. 1. Figs. 8 and 9 are exploded perspective views showing the right and left switching mechanisms 200 in the fixing device 9 shown in Fig. 1, respectively.

[0029] Fig. 10 is a perspective view showing a state in which the second opening / closing member 120 is opened and the pressure member 92 is in a pressure-released state due to the action of the switching member 240 (240, 240) in the fixing device 9 shown in Fig. 1. Fig. 11 is an enlarged perspective view showing the sliding contact portion 111 (111, 111) of the first opening / closing member 110 shown in Fig. 6.

[0030] <Switching mechanism> The fixing device 9 includes a switching mechanism 200 that can switch between a pressure-applied state and a pressure-released state of a pressure member 92 with respect to a rotatable fixing member 91 using a switching member 240 (240, 240). In this example, the switching mechanism 200 is a pair of switching mechanisms 200, 200 provided at both ends in the rotation axis direction W. Each of the pair of switching mechanisms 200, 200 includes a support member 210, a pressing member 220, a biasing member 230 (a coil spring in this example), and a switching member 240. That is, the support member 210 is a pair of support members 210, 210, the pressing member 220 is a pair of pressing members 220, 220, the biasing member 230 is a pair of biasing members 230, 230, and the switching member 240 is a pair of switching members 240, 240.

[0031] The support members 210 support the pressure member 92 so that it can move toward and away from the fixing member 91. Specifically, the support members 210 support the pressure member 92 so that it can rotate about a rotation axis α2 (see FIG. 3), while swinging it about a swing axis δ (see FIGS. 4, 7, and 8) along the rotation axis direction W with respect to the fixing device main body 901. In this example, swing shafts 901a extending along the rotation axis direction W are fixed to both ends of the fixing device main body 901 in the rotation axis direction W.

[0032] The support members 210, 210 are each provided with an engagement portion 210a, 210a (engagement recess) into which a swing shaft 901a, 901a of the fixing device main body 901 is engaged, and recesses 210b, 210b that receive a rotation shaft 92b, 92b of the pressure roller (92). The pressure roller (92) is composed of a roller portion 92a that fixes a toner image on a sheet P, and rotation shafts 92b, 92b provided at both ends of the roller portion 92a in the rotation axis direction W. The rotation shafts 92b, 92b of the pressure roller (92) are supported by recesses 210b, 210b of the support members 210, 210 via bearing members 92c, 92c. This allows the support members 210, 210 to support the pressure member 92 rotatably about the rotation axis α2 and movable toward and away from the fixing member 91 about the swing axis δ.

[0033] The pressing members 220 are supported relative to the support members 210 so as to be movable in the approaching and separating direction S of the pressure member 92 (in this example, the depth direction Y), and are biased by biasing members 230 toward a separating direction S2 in the approaching and separating direction S. More specifically, the support members 210 have a pair of side plates 211 and a connecting plate 212 connecting the pair of side plates 211. The pair of side plates 211 and the connecting plate 212 are integrally formed. Slits 211a are provided along the approaching and separating direction S on the opposite side of the engagement portion 210a across the recesses 210b of the pair of side plates 211 in the radial direction of the oscillation axis δ.

[0034] The pressing members 220, 220 are provided with a pressing surface 220a that presses the connecting plate 212 of the support members 210, 210 via the biasing members 230, 230, and a pair of protrusions 220b, 220b that are inserted into the slits 211a, 211a, respectively. This allows the support members 210, 210 to support the pressing members 220, 220 so that they can move (slide) in the approaching and separating direction S in a state where they are biased in the separating side direction S2 by the biasing members 230, 230.

[0035] The connecting plate 212 has a contacted surface 212a that faces the pressing surface 220a of the pressing members 220 and is perpendicular to the contact and separation direction S. The biasing members 230 are disposed between the contacted surfaces 212a of the connecting plates 212 and the pressing surfaces 220a of the pressing members 220.

[0036] The switching members 240, 240 are provided with an engagement portion 240a (engagement hole) (see FIG. 8), a lever portion 240b, a first contact surface 240c, and a second contact surface 240d.

[0037] Switching rotation shafts 901b, 901b extending along the rotation axis direction W are fixed to both ends of the fixing device main body 901 in the rotation axis direction W. The engagement portions 240a, 240a of the switching members 240, 240 are inserted into the switching rotation shafts 901b, 901b of the fixing device main body 901, respectively. This allows the switching members 240, 240 to rotate around a switching rotation axis β (see FIGS. 4 and 7) that is aligned with the rotation axis α1 of the fixing member 91.

[0038] The lever portion 240b is gripped by an operator. The first abutment surface 240c and the second abutment surface 240d are flat surfaces that extend along both the longitudinal direction of the lever portion 240b and the direction of the rotation axis W, and are connected so that the angle formed between the first abutment surface 240c and the second abutment surface 240d is an obtuse angle. The distance d1 (see FIG. 8) between the first abutment surface 240c and the switching rotation axis β is greater than the distance d2 (see FIG. 8) between the second abutment surface 240d and the switching rotation axis β (d1>d2).

[0039] When the operator rotates the lever portion 240b of the switching members 240 in a direction intersecting the approaching / separating direction S, the first contact surface 240c of the switching members 240 comes into contact with the pressing surface 220a of the pressing member 220. At this time, the switching members 240 go beyond the top dead center (the corner between the first contact surface 240c and the second contact surface 240d) in the process of moving from the second contact surface 240d to the first contact surface 240c, and the contact of the first contact surface 240c with the pressing surface 220a is maintained. Then, the first contact surfaces 240c of the switching members 240 press against the pressing surfaces 220a of the pressing members 220, thereby pressing the connecting plates 212 of the support members 210 in the approaching-side direction S1 in the approaching-separating direction S against the biasing force of the biasing members 230. This allows the pressure member 92 to be in a state of pressing against the fixing member 91.

[0040] Furthermore, when the operator rotates the lever portion 240b of the switching member 240 along the approaching / separating direction S, the second abutment surface 240d of the switching member 240 comes into contact with the pressing surface 220a of the pressing member 220. At this time, the switching member 240 passes the top dead center (the corner between the first abutment surface 240c and the second abutment surface 240d) in the process of moving from the first abutment surface 240c to the second abutment surface 240d, and the abutment of the second abutment surface 240d with the pressing surface 220a is maintained. Then, when the second abutment surface 240d of the switching member 240 is released from pressing the pressing surface 220a of the pressing member 220, the pressure on the connecting plate 212 of the support member 210 via the biasing member 230 is released. This allows the pressure member 92 to be released from the pressure applied to the fixing member 91 .

[0041] (About this embodiment) In this embodiment, as described above, the fixing device 9 is configured so that the pressure member 92 (in this example, a pressure roller) can be switched between a pressure-applied state and a pressure-released state relative to the rotatable fixing member 91 (in this example, a fixing belt) by the switching member 240.

[0042] The first opening / closing member 110 (see FIGS. 1, 5, and 6) covers the fixing device 9 when closed, and exposes all or part of the fixing device 9 when opened. The second opening / closing member 120 covers a component (pressure member 92 in this example) inside the fixing device main body 901 when closed, and exposes all or part of the component (92) when opened.

[0043] Here, "rotation" means that the target member rotates 360 degrees or more, and "pivot" means that the target member rotates less than 360 degrees.

[0044] 1, 5, and 6, the first opening / closing member 110 is rotatable about a first rotation axis γ1 along the rotation axis direction W. As shown in FIGS. 5 and 6, the first opening / closing member 110 is provided to be rotatable about the first rotation axis γ1 relative to the image forming apparatus main body 101.

[0045] More specifically, a pair of engagement portions 101a (engagement holes) are provided on both inner side surfaces in the rotation axis direction W above the paper feed unit 13 at the bottom of the image forming apparatus main body 101. A pair of rotation support shafts 110a extending outward along the rotation axis direction W is provided on both outer side surfaces in the rotation axis direction W at the lower end of the first opening / closing member 110. The rotation support shafts 110a of the first opening / closing member 110 are engaged with the engagement portions 101a of the image forming apparatus main body 101, respectively. This allows the first opening / closing member 110 to rotate about the first rotation axis γ1, and to open and close with respect to the image forming apparatus main body 101.

[0046] The image forming apparatus main body 101 is provided with a locking mechanism 300 (see FIGS. 1 and 5) that releasably locks the first opening / closing member 110 to the fixing device main body 901.

[0047] The locking mechanism 300 includes one or more (two in this example) engaging portions 310, 310 (convex portions in this example) provided on the first opening / closing member 110, one or more (two in this example) locking portions 320, 320 (concave portions in this example) provided on the image forming apparatus main body 101 for locking the engaging portions 310, 310, and biasing members 330, 330 (coil springs).

[0048] The first opening / closing member 110 is provided with storage chambers 110b that store the engaging portions 310 and the biasing members 330. The engaging portions 310 are provided in the storage chambers 110b so as to be movable in a contact / separation direction T (a radial direction centered on the first rotation axis γ1) in which they approach and move away from the locking portions 320. The engaging portions 310 have sharpened tip portions 310a. The biasing members 330 are disposed between the bottom surfaces of the storage chambers 110b and the engaging portions 310, and bias the engaging portions 310 in the contact / separation direction T in the opposite direction from the first rotation axis γ1. The first opening / closing member 110 is provided with a slip-out prevention portion (not shown) that prevents the engaging portions 310 from slipping out toward the locking portions 320. This allows the engaging portions 310 to be freely movable in the approaching / separating direction T while being biased toward the locking portions 320 by the biasing members 330 relative to the first opening / closing member 110. The locking portions 320 are recesses provided in the image forming apparatus main body 101.

[0049] 2 and 4, the second opening / closing member 120 is openable and closable about a second rotation axis γ2 that is aligned with the rotation axis α1 of the fixing member 91. The second opening / closing member 120 is provided to be openable and closable about the second rotation axis γ2 relative to the fixing device main body 901. More specifically, a pair of engagement portions 901c (engagement recesses) are provided at both ends in the rotation axis direction W of the lower portion of the fixing device main body 901 that faces the first opening / closing member 110. A pair of rotation support shafts 120a are provided at the lower end of the second opening / closing member 120 and at both ends in the rotation axis direction W. The rotation support shafts 120a are engaged with the engagement portions 901c of the fixing device main body 901, respectively. As a result, the second opening / closing member 120 can rotate about the second rotation axis γ2 relative to the fixing device main body 901, and can be opened and closed relative to the fixing device main body 901.

[0050] The first opening / closing member 110 is provided with sliding contact portions 111 (an example of a first acting portion) (FIGS. 6 and 11) that slide against the switching members 240 when the first opening / closing member 110 is closed, thereby causing the switching members 240 to act. The second opening / closing member 120 is provided with abutment portions 121 (an example of a second acting portion) (FIG. 4) that abut against the switching members 240 when the second opening / closing member 120 is opened, thereby causing the switching members 240 to act.

[0051] 12 to 16 are cross-sectional views showing the first to fifth closing steps in which the first opening / closing member 110 is closed. Figs. 17 and 18 are cross-sectional views showing the unlocked state and locked state of the locking mechanism 300. Figs. 19 to 23 are cross-sectional views showing the first to fifth opening steps in which the second opening / closing member 120 is opened.

[0052] In this embodiment, when the first opening / closing member 110 is rotated from an open state in the opening direction M1 to the closing direction M2 while the second opening / closing member 120 is closed in the closing direction N2 (see FIG. 12), the sliding contact portions 111, 111 of the first opening / closing member 110 come into sliding contact with the switching members 240, 240, and actuate the switching members 240, 240 (see FIGS. 13 and 14). At this time, the switching members 240, 240 rotate from the pressure release side to the pressure side (direction of arrow L1 in the figure) of the pressure member 92, and the second abutment surface 240d, which is in contact with the pressing surface 220a of the pressing member 220, moves away from the pressing surface 220a, and the first abutment surface 240c moves close to the pressing surface 220a. The first opening / closing member 110 has engagement portions 310, 310 of the locking mechanism 300 approaching the latching portions 320, 320 of the locking mechanism 300 provided in the image forming apparatus main body 101 (see FIG. 17).

[0053] When the first opening / closing member 110 is further rotated in the closing direction M2, the switching members 240, 240 exceed the top dead center in the process of moving from the second abutment surface 240d to the first abutment surface 240c (see FIGS. 13 and 14), and the first abutment surface 240c abuts against the pressing surface 220a of the pressing member 220 (see FIG. 15), and the abutment of the first abutment surface 240c against the pressing surface 220a is maintained (see FIG. 16). The engaging portions 310, 310 of the locking mechanism 300 are engaged with the engaging portions 320, 320 of the locking mechanism 300 provided in the image forming apparatus main body 101, and the first opening / closing member 110 is locked (see FIG. 18).

[0054] In this manner, the image forming apparatus 100 can change the pressure member 92 from the pressure release state to the pressure applying state using the switching members 240, 240 by the operator closing the first opening / closing member 110.

[0055] On the other hand, when the engagement portions 310, 310 of the locking mechanism 300 are released from the engagement portions 320, 320 of the locking mechanism 300 provided in the image forming apparatus main body 101 (see FIG. 17), the first opening / closing member 110 rotates in the opening direction M1.

[0056] When the second opening / closing member 120 is rotated from a closed state (see FIG. 19) in the closing direction N2 to the opening direction N1 (see FIG. 20) while the first opening / closing member 110 is open in the opening direction M1, the abutment portions 121 of the second opening / closing member 120 abut against the switching members 240, causing the switching members 240 to operate (see FIGS. 21 and 22). At this time, the switching members 240 rotate from the pressure side of the pressure member 92 to the pressure release side (the direction of arrow L2 in the figure), and the first abutment surface 240c, which is in contact with the pressing surface 220a of the pressing member 220, moves away from the pressing surface 220a, and the second abutment surface 240d moves close to the pressing surface 220a.

[0057] When the second opening / closing member 120 is further rotated in the opening direction N1, the switching members 240, 240 pass the top dead center during the transition from the first abutment surface 240c to the second abutment surface 240d (see Figure 23), and the second abutment surface 240d abuts against the pressing surface 220a of the pressing member 220, and the abutment of the second abutment surface 240d against the pressing surface 220a is maintained.

[0058] In this way, the image forming apparatus 100 can switch the pressure member 92 from the pressure-applied state to the pressure-released state using the switching members 240, 240 by the operator opening the second opening / closing member 120.

[0059] That is, the first opening / closing member 110 is used for switching from the pressure-released state to the pressure-applied state, and the second opening / closing member 120 is used for switching from the pressure-applied state to the pressure-released state. In this way, unlike the conventional configuration, switching from the pressure-applied state to the pressure-released state and from the pressure-applied state to the pressure-applied state is not performed using a single opening / closing member, so it is possible to avoid the configuration of the first opening / closing member 110, the second opening / closing member 120, and the switching members 240, 240 required for each switching operation becoming complicated. Therefore, it is possible to easily switch the pressure member 92 relative to the fixing member 91 from the pressure-released state to the pressure-applied state and from the pressure-applied state to the pressure-released state without complicating the configuration of the fixing device 9.

[0060] (First embodiment) In this embodiment, the first opening / closing member 110 is provided with a first action portion (sliding contact portion 111 in this example) (see FIG. 11 ) that acts on the switching members 240, 240 when the first opening / closing member 110 is closed. This allows the pressure member (92) to easily change from a pressure-released state to a pressure-applied state.

[0061] More specifically, the sliding contact portion 111 slides against the switching members 240, 240 when the first opening / closing member 110 is closed, thereby causing the switching members 240, 240 to operate.

[0062] In this configuration, the sliding contact portions 111, 111 of the first opening / closing member 110 are in sliding contact with the switching members 240, 240, and yet the pressure member (92) can be reliably switched from the pressure-released state to the pressure-applied state.

[0063] In this example, the lever portion 240b of the switching members 240, 240 is inclined at an obtuse angle at a bent portion 240e on the second opening / closing member 120 side, and an inclined surface 240f and a side surface 240g are connected across the bent portion 240e. The inclined surface 240f is formed in a direction intersecting the longitudinal direction of the lever portion 240b. The side surface 240g is connected to the inclined surface 240f and is formed along both the longitudinal direction of the lever portion 240b and the rotation axis direction W. The sliding contact portions 111, 111 have a curved surface 111a. The curved surface 111a is formed in a concave curved shape so that the inclined surface 240f and the bent portion 240e of the switching member 240 slide in contact with each other in this order when the first opening / closing member 110 is closed in the closing direction N2.

[0064] (Second embodiment) In this embodiment, the second opening / closing member 120 is provided with a second action portion (contact portion 121 in this example) (see FIG. 4) that acts on the switching members 240, 240 when the second opening / closing member 120 is opened.

[0065] More specifically, the contact portion 121 contacts the switching members 240, 240 when the second opening / closing member 120 is opened, thereby causing the switching members 240, 240 to operate.

[0066] In this configuration, although it is a simple configuration in which the second acting portions (121, 121) in the second opening / closing member 120 act (abut) on the switching members 240, 240, the pressing member (92) can be surely changed from the pressed state to the pressure release state.

[0067] In this example, the abutting portions 121, 121 project outward from both ends of the second opening / closing member 120 on the second rotation axis γ2 so as to abut on the inner surface 240b1 (see FIG. 4) of the lever portion 240b of the switching member 240 when the second opening / closing member 120 opens in the opening direction M1, and rotate the switching member 240 from the pressurized side of the pressing member 92 to the pressure release side (L2 direction).

[0068] (Third Embodiment) By the way, when the second opening / closing member 120 is closed, if the second acting portion (121) is closer to the switching rotation axis β side than the second rotation axis γ2 side, the force for the operator to open and close the second opening / closing member 120 tends to be large. Further, the rotation angles of the switching members 240, 240 tend to be large, and then, when the operator performs the jamming process (jam process) of the sheet P with the fixing device 9, the switching members 240, 240 tend to be in the way.

[0069] In this regard, in the present embodiment, as shown in FIG. 4, when the second opening / closing member 120 is closed, the second acting portions (121, 121) are closer to the second rotation axis γ2 side than the switching rotation axis β side.

[0070] In this configuration, when the operator opens and closes the second opening / closing member 120, the force for the operator to open and close the second opening / closing member 120 can be suppressed to be small. Further, the rotation angles of the switching members 240, 240 can be made as small as possible, and thereby, when the operator performs the jamming process of the sheet P with the fixing device 9, the switching members 240, 240 can be made less likely to be in the way. This is particularly effective when the distance d3 between the second acting portions (121, 121) and the second rotation axis γ2 is smaller than the distance d4 between the second acting portions (121, 121) and the outer surface 120b of the second opening / closing member 120 (d3 < d4).

[0071] Specifically, when the second opening / closing member 120 is closed, the lever portion 240b of the switching member 240 is located between the second action portion (121) and the outer surface 120b of the second opening / closing member 120. The second action portion (121) is closer to the tip end 241 of the lever portion 240b of the switching member 240 than to the switching rotation axis β. The tip end 241 of the lever portion 240b of the switching member 240 is located between the second action portion (121) and the second rotation axis γ2 in the longitudinal direction of the lever portion 240b. The second rotation axis γ2 of the second opening / closing member 120 is located on the opposite side of the switching rotation axis β of the switching member 240 in the longitudinal direction of the lever portion 240b, with the fixing nip portion FN therebetween.

[0072] (Fifth embodiment) In this embodiment, the switching members 240, 240 and the second opening / closing member 120 overlap when the second opening / closing member 120 is closed (see Figure 4), when viewed from the rotational axis direction W of the fixing member 91, and do not overlap when the second opening / closing member 120 is fully open (see Figure 23).

[0073] In this configuration, the switching members 240, 240 and the second opening / closing member 120 overlap when viewed from the rotation axis direction W, when the second opening / closing member 120 is closed, thereby realizing a compact fixing device 9. Furthermore, since the switching members 240, 240 do not overlap when the second opening / closing member 120 is fully open, the fully open angle of the second opening / closing member 120 relative to the posture angle of the second opening / closing member 120 when closed can be increased, making it easier for the operator to remove jammed sheets P in the fixing device 9.

[0074] (Sixth embodiment) In this embodiment, the directions in which the switching members 240 and the second opening / closing member 120 rotate are different in the process of transition between the pressurized state and the pressurized released state.

[0075] In this configuration, during the transition between the pressurized state and the depressurized state, the directions in which the switching members 240, 240 and the second opening / closing member 120 rotate are different, so that when the second opening / closing member 120 operates the switching members 240, 240, the rotation angle of the switching members 240, 240 can be made as small as possible.

[0076] Seventh embodiment Incidentally, if the configuration allows the switching members 240, 240 to be operated to the pressurized state when the second opening / closing member 120 is open, the pressing member 92 will be pressed when the operator operates the switching members 240, 240 to the pressurized state when the second opening / closing member 120 is open. In this case, the pressing member 92 will be pressed even though the second opening / closing member 120 is open, and the operator will not be able to reliably remove jammed sheets P in the fixing device 9.

[0077] In this regard, in the present embodiment, the switching members 240, 240 are restricted from being operated to the pressurized state when the second opening and closing member 120 is open. In this example, even if an attempt is made to operate the switching members 240, 240 to the pressurized state when the second opening and closing member 120 is open, the tip ends of the switching members 240, 240 abut against the abutment portions 121, 121 of the second opening and closing member 120 (see FIGS. 22 and 23). Here, "the second opening and closing member 120 is open" refers to an open state (including a state where the second opening and closing member 120 is fully open) other than the closed state.

[0078] In this configuration, since the switching members 240, 240 are restricted from being operated to the pressurized state when the second opening / closing member 120 is open (in this example, even if an attempt is made to operate the switching members 240, 240 to the pressurized state, the switching members 240, 240 come into contact with the contact portions 121, 121 of the second opening / closing member 120, and the contact portions 121, 121 get in the way), it is possible to prevent the pressing member 92 from being pressed when the operator operates the switching members 240, 240 to the pressurized state when the second opening / closing member 120 is open. This allows the operator to reliably remove jammed sheets P in the fixing device 9.

[0079] (Eighth embodiment) In this embodiment, the second opening / closing member 120 is a transport guide member that guides the sheet P transported to its outer surface. The first opening / closing member 110 is an exterior cover member of the image forming apparatus main body 101 that, together with the transport guide member that is the second opening / closing member 120, forms a transport path for the sheet P (in this example, a part of the sheet reversal transport path 17) (see FIG. 1).

[0080] In this configuration, the first opening / closing member 110 and the second opening / closing member 120 can also serve as a conveyance path for the sheet P, and the first opening / closing member 110 can also serve as an exterior cover.

[0081] The present disclosure is not limited to the above-described embodiments, but can be implemented in various other forms. Therefore, the embodiments are merely examples in all respects and should not be interpreted as being limiting. The scope of the present disclosure is defined by the claims and is not bound by the text of the specification. Furthermore, all modifications and variations within the equivalent scope of the claims are within the scope of the present disclosure. [Explanation of symbols]

[0082] 100 Image forming device 101 Image forming apparatus main body 101a Section 110 First opening / closing member 110a Rotating spindle 111 sliding contact portion (an example of a first action portion) 111a curved surface 120 second opening / closing member 120a Rotating spindle 121 contact portion (an example of a second action portion) 17 Sheet reversing transport path 200 Switching mechanism 210 Support member 210a Section 210b recess 211 Side panel 211a Slit 212 Connecting plate 212a Abutted surface 220 Pressing member 220a Pressing surface 220b Protrusion 230 biasing member 240 Switching member 240a Section 240b Lever part 240b1 Inside surface 240c 1st contact surface 240d 2nd contact surface 240e Bend section 240f slope 240g side 300 Locking mechanism 310 Engagement part 310a Tip 320 Locking part 330 biasing member 9 Fixing device 901 Fixing device body 901a Oscillating shaft 901b Switching pivot shaft 901c Section 91 Fixing member 92 Pressure member 92a Roller part 92b Rotation axis 92c Bearing material 93 Support member H Conveying direction M1 opening direction M2 closing direction N1 Opening direction N2 closing direction P-sheet S Approach / Separation Direction S1 Near side direction S2 Separation side direction T Approach / Separation Direction W Rotation axis direction X Width direction Y depth direction α1 Rotation axis α2 rotation axis β Switching rotation axis γ1 First rotation axis γ2 Second rotation axis δ Swing axis

Claims

1. An image forming apparatus including a fixing device configured to be able to switch between a pressure state and a pressure release state of a pressure member with respect to a rotatable fixing member by a switching member, a first opening / closing member that covers the fixing device in a closed state and exposes the fixing device in an open state; the fixing device includes a second opening / closing member that covers components inside the fixing device body in a closed state and exposes the components in an open state; When the first opening / closing member is closed from an open state, the switching member is actuated to change the pressure member from the pressure release state to the pressure state, The image forming apparatus according to claim 1, wherein when the second opening / closing member is opened from a closed state, the second opening / closing member operates the switching member to change the pressure member from the pressure state to the pressure release state.

2. 2. The image forming apparatus according to claim 1, The image forming apparatus according to claim 1, wherein the first opening / closing member is provided with a first action portion that causes the switching member to act when the first opening / closing member is closed.

3. 2. The image forming apparatus according to claim 1, The image forming apparatus according to claim 1, wherein the second opening / closing member is provided with a second action portion that causes the switching member to act when the second opening / closing member is opened.

4. 2. The image forming apparatus according to claim 1, the switching member rotates about a switching rotation axis that is aligned with the rotation axis of the fixing member, the second opening / closing member is openable and closable about a second rotation axis along the rotation axis, The second opening / closing member is provided with a second action portion that causes the switching member to act when the second opening / closing member is opened, The image forming apparatus, wherein, when the second opening / closing member is closed, the second action portion is closer to the second rotation axis side than to the switching rotation axis side.

5. 2. The image forming apparatus according to claim 1, an image forming apparatus characterized in that, when viewed from the direction of the rotation axis of the fixing member, the switching member and the second opening / closing member overlap when the second opening / closing member is closed, and do not overlap when the second opening / closing member is fully open.

6. 2. The image forming apparatus according to claim 1, The image forming apparatus according to claim 1, wherein the switching member and the second opening / closing member rotate in different directions during the transition between the pressurized state and the pressure-released state.

7. 2. The image forming apparatus according to claim 1, An image forming apparatus, characterized in that, when the second opening / closing member is open, the switching member is restricted from being operated to the pressurized state.

8. 2. The image forming apparatus according to claim 1, An image forming apparatus characterized in that the second opening and closing member is a transport guide member that guides a sheet transported to its outer surface, and the first opening and closing member is an outer cover member of the image forming apparatus main body that forms a transport path for the sheet together with the transport guide member that is the second opening and closing member.

Images