Sheet conveying device

Abstract

To accurately position a first opening / closing part at a first closing position.SOLUTION: A sheet conveyance device (1) includes a device main body (side 1A) having a first guide, a first openable portion (320) supported by the device main body (side 1A) so as to be openable and closable relative to the device main body (side 1A) and having a second guide that faces the first guide in a closed state and forms a conveyance path through which a sheet is conveyed, A second opening-closing portion (320) configured to cover the first opening-closing portion (320) when the second opening-closing portion (310) is in a closed state; an engaged portion (333) provided on the main body (side 1A); And a locking mechanism (340) for locking the second opening / closing part (310) to the device body (side 1A) by engaging with the engaged part (333) in a state where the second opening / closing part (320) is closed, wherein the first opening / closing part (320) is positioned by abutting on the locking mechanism (340) in the state where the second opening / closing part (310) is closed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device that includes a first opening / closing unit and a second opening / closing unit that can be opened and closed relative to a device main body. [Background technology]

[0002] For example, in an image forming apparatus, if a sheet jam occurs, the user is required to open the door to open the sheet transport path and remove the jammed sheet. Also, in an image forming apparatus having a so-called double structure in which there are two sheet transport paths inside the apparatus, one on the outside and one on the inside, an apparatus has been proposed that has an outer door and an inner door that can be opened to open the inner sheet transport path (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-19940 Summary of the Invention [Problem to be solved by the invention]

[0004] In an image forming apparatus having an outer door and an inner door as described above, if a locking mechanism that locks each door to the device body is provided, it would be necessary to unlock both the outer door and the inner door, resulting in poor operability. Therefore, it is preferable to lock the inner door so that it is positioned in the closed position when the outer door is closed with the locking mechanism. However, even if the outer door is locked to the device body with the locking mechanism, there is a risk of play occurring in the outer door due to component tolerances, etc., and even if such an outer door is used to position the inner door, there is a risk that the positioning accuracy of the inner door will be poor. This can lead to an increase in sheet jams in the inner sheet transport path formed by the inner door.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet conveying device that is capable of accurately positioning a first opening / closing section at the first closed position. [Means for solving the problem]

[0006] One aspect of the present invention is a sheet transport device comprising: an apparatus main body having a first guide; a first opening / closing unit supported so as to be openable and closable relative to the apparatus main body and having a second guide that, when closed, forms a transport path along which sheets are transported opposite the first guide; a second opening / closing unit supported so as to be openable and closable relative to the apparatus main body and that covers the first opening / closing unit when closed; an engaging unit provided on the apparatus main body; and a locking mechanism supported by the second opening / closing unit and that engages with the engaging unit when the second opening / closing unit is closed, thereby locking the second opening / closing unit to the apparatus main body; and the first opening / closing unit is positioned by abutting against the locking mechanism when the second opening / closing unit is closed. [Effects of the Invention]

[0007] According to the present invention, the first opening / closing part can be positioned at the first closed position with high precision. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1A is a front cross-sectional view showing the reversing mechanism according to the present embodiment when the outer and inner doors are closed, and FIG. 1B is a front cross-sectional view showing the reversing mechanism according to the present embodiment when the outer and inner doors are open. [Figure 3] 1A is a front cross-sectional view showing the locking mechanism and the biasing mechanism in a state where the outer door and the inner door are closed, and FIG. 1B is a front cross-sectional view showing the locking mechanism and the biasing mechanism in a state where the outer door and the inner door are open, according to the present embodiment. [Figure 4] 3(a) is a cross-sectional view taken along the line AA in FIG. 3(a), and FIG. 3(b) is a cross-sectional view taken along the line AA in FIG. 3(b). [Figure 5] 3(a) is a cross-sectional view taken along the line BB in FIG. 3(a), and FIG. 3(b) is a cross-sectional view taken along the line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] This embodiment will be described in detail below with reference to the drawings.

[0010] [Image forming device overview] First, a schematic configuration of an image forming apparatus 1, which is an example of a sheet conveying apparatus according to this embodiment, will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing the schematic configuration of the image forming apparatus according to this embodiment.

[0011] The image forming apparatus 1 shown in FIG. 1 is, for example, a color image forming apparatus using an electrophotographic method, and includes a sheet supply section 1B, a sheet conveying section 1C, an image forming section 1D, a secondary transfer section 1E, a fixing section 1F, a reverse conveying section 1G, a double-sided conveying section 1H, etc. inside the apparatus main body 1A.

[0012] Sheet supply unit 1B includes feed cassettes 61, 62, and 63 which store sheets, and feed units 61a, 62a, and 63a which feed sheets S set in feed cassettes 61, 62, and 63, respectively, one by one in the direction of arrow A. Sheets S of different sizes, paper types, and the like can be set in these feed cassettes 61, 62, and 63. Sheet supply unit 1B also includes a manual feed tray 64 into which sheets S can be manually fed, and a feed unit 64a which feeds sheets S set in this manual feed tray 64 one by one. Sheets S fed from sheet supply unit 1B are supplied to sheet conveying unit 1C.

[0013] The sheet conveying section 1C includes a conveying roller pair 130, pre-registration roller pairs 120 and 140, a registration roller pair 110, and a conveying belt unit 42. A sheet S fed from one of the feeding cassettes 61, 62, or 63, or a sheet S conveyed from a duplex conveying section 1H (described later), is conveyed to the registration roller pair 110 by the conveying roller pair 130 and the pre-registration roller pair 120. A sheet S conveyed from the manual feed tray 64 is conveyed to the registration roller pair 110 by the pre-registration roller pair 140. The sheet S conveyed in this manner abuts against the nip of the registration roller pair 110, which is stationary. Then, while the leading edge of the sheet S is abutted against the nip, a flexure is formed as the sheet S is conveyed by the pre-registration roller pairs 120 and 140, thereby correcting skew. Thereafter, the registration roller pair 110 starts to rotate at a timing that matches the toner image formed on the intermediate transfer belt 31 in the image forming unit 1D, and the sheet S is transported to the secondary transfer unit 1E at that timing. Then, the sheet S onto which the toner image has been secondarily transferred in the secondary transfer unit 1E is vacuum-adsorbed by the transport belt unit 42 and transported to the fixing unit 1F.

[0014] On the other hand, image forming unit 1D is configured to include photoconductors 11 corresponding to the colors yellow (Y), magenta (M), cyan (C), and black (Bk), charging devices 12, exposure devices 13 that function as image writing units, and developing devices 14. Note that although the subscripts of each reference numeral in the figure correspond to each color, they all have the same function. Image forming unit 1D also includes an intermediate transfer belt 31, a secondary transfer inner roller 32, a drive roller 33, a tension roller 34, and a primary transfer device 35.

[0015] In the image forming unit 1D, the surface of the photoreceptor 11, which is an image carrier, is uniformly charged in advance by the charging device 12, and the exposure device 13 is driven based on an image information signal to form a latent image on the surface of the rotating photoreceptor 11. The electrostatic latent image formed on the surface of the photoreceptor 11 is developed with toner by the developing device 14 and becomes a visible toner image. Thereafter, a predetermined pressure and electrostatic bias are applied by the primary transfer device 35, and the toner image is transferred onto the intermediate transfer belt 31.

[0016] The intermediate transfer belt 31 is stretched by rollers such as a drive roller 33, a tension roller 34, and a secondary transfer inner roller 32, and is driven to be transported in the direction of arrow B shown in FIG. 1. The image formation processes for each color of Y, M, C, and Bk, which are processed in parallel, are timed and superimposed on the toner images of the upstream colors that have been primarily transferred onto the intermediate transfer belt 31. As a result, a full-color toner image is finally formed on the intermediate transfer belt 31, and this toner image is transported to the secondary transfer unit 1E.

[0017] The secondary transfer unit 1E has an outer secondary transfer roller 41 facing the inner secondary transfer roller 32, and these inner secondary transfer roller 32 and outer secondary transfer roller 41 form a secondary transfer nip. The secondary transfer unit 1E transfers a toner image onto the sheet S by applying a predetermined pressure and electrostatic bias to this secondary transfer nip. The sheet S onto which the toner image has been transferred is transported to the fixing unit 1F by the transport belt unit 42 as described above.

[0018] The fixing section 1F is provided with a fixing roller pair 50 having a fixing roller 51 and a pressure roller 52, and the fixing roller pair 50 pressurizes and heats the sheet S, melting and fixing the toner image to the sheet S. The sheet S with the melted and fixed toner image is discharged from the fixing roller pair 50 by a post-fixing roller pair 53 and conveyed to the reverse conveying section 1G.

[0019] The reversing conveying section 1G is configured to have a discharge conveying path 82, a reversing conveying path 83, a post-reversal discharge path 84, a first switching section 81, a conveying roller pair 90, a conveying roller pair 91, a first reversing roller pair 92, a discharge roller pair 93, and a reversing mechanism 300. The reversing mechanism 300 of the reversing conveying section 1G is configured to have a second reversing roller pair 302, an evacuation introduction path 381 and an evacuation path 382 which are conveying paths connected to the reversing conveying path, a re-conveying introduction path 383 which is a conveying path connected to the double-sided conveying section 1H, and a second switching section 324.

[0020] Specifically, the first switching unit 81 switches the conveyance destination of the sheet S between the discharge conveyance path 82 and the reversing conveyance path 83. The first reversing roller pair 92 is, for example, drive-coupled to a motor capable of forward and reverse rotation, thereby switching the conveyance direction of the sheet S conveyed to the reversing conveyance path 83 between the retreat path 382 of the reversing mechanism 300 and the post-reversal discharge path 84. The second reversing roller pair 302 arranged in the retreat path 382 is provided downstream in the conveyance direction (vertically below) of the branch point of the retreat introduction path 381 and the re-conveyance introduction path 383. The second reversing roller pair 302 is, for example, drive-coupled to a motor capable of forward and reverse rotation, thereby switching the conveyance direction of the sheet between the retreat introduction path 381 and the re-conveyance introduction path 383. The second switching section 324 is arranged at the branch point of the retreat introduction path 381 and the re-conveyance introduction path 383, and guides the sheet S that has been inverted after being transported from the retreat introduction path 381 to the second reversal roller pair 302 to the re-conveyance introduction path 383 without causing it to flow backward.

[0021] Here, when the sheet passing mode of the sheet S is single-sided face-up passing, the destination of the sheet S conveyed by the post-fixing roller pair 53 is switched to the discharge conveying path 82 by the first switching unit 81. The sheet S conveyed to the discharge conveying path 82 is conveyed by the conveying roller pair 91, and is discharged and stacked on a discharge tray 99 arranged outside the apparatus main body 1A (i.e., outside the machine) by the discharge roller pair 93.

[0022] On the other hand, when the sheet passing mode of the sheet S is single-sided face-down passing, the destination of the sheet S conveyed by the post-fixing roller pair 53 is first switched to the reverse conveying path 83 by the first switching unit 81. The sheet S conveyed to the reverse conveying path 83 is conveyed to the first reverse roller pair 92 by the conveying roller pair 90, and is conveyed to the retraction introduction path 381 and the retraction path 382 of the reversing mechanism 300. Thereafter, the conveying direction of the sheet S is switched to the post-reversal discharge path 84 by the first reverse roller pair 92, which can switch the conveying direction (rotation direction), and the sheet S is conveyed, and is discharged to the discharge tray 99 by the discharge roller pair 93.

[0023] When the sheet P is in double-sided printing mode, the destination of the sheet S, which has an image formed on its first side and is conveyed by the post-fixing roller pair 53, is similarly switched to the reverse conveyance path 83 by the first switching unit 81. The sheet S conveyed to the reverse conveyance path 83 is conveyed to the first reverse roller pair 92 by the conveyance roller pair 90, and then conveyed to the retraction introduction path 381 and the retraction path 382 of the reversing mechanism 300. Next, in the reversing mechanism 300, when the trailing end of the sheet S conveyed to the retraction path 382 passes through the second switching unit 324, the conveyance direction (rotation direction) is switched by the second reverse roller pair 302, which is capable of switching the conveyance direction, to the re-conveyance introduction path 383, and the sheet is conveyed thereto. As a result, the sheet S, which has an image formed on its first side, is conveyed to the double-sided conveyance unit 1H and then conveyed to the secondary transfer unit 1E by the sheet conveyance unit 1C described above. That is, the sheet S is re-conveyed to the secondary transfer unit 1E with the first and second sides reversed. Then, the sheet S passes through the secondary transfer unit 1E and the fixing unit 1F, whereby an image is formed on the second side. Thereafter, the conveying destination of the sheet S is switched to the discharge conveying path 82 by the first switching unit 81, and the sheet S with the toner image fused and fixed thereon is discharged onto the discharge tray 99 by the pair of discharge rollers 93.

[0024] [About the double door structure] Next, the double-door structure of the image forming apparatus 1 according to this embodiment will be described with reference to FIGS. 2, 3, and 4. FIG. 2(a) is a front cross-sectional view of the reversing mechanism according to this embodiment with the outer and inner doors closed. FIG. 2(b) is a front cross-sectional view of the reversing mechanism according to this embodiment with the outer and inner doors open. FIG. 3(a) is a front cross-sectional view of the locking mechanism and the biasing mechanism according to this embodiment with the outer and inner doors closed. FIG. 3(b) is a front cross-sectional view of the locking mechanism and the biasing mechanism according to this embodiment with the outer and inner doors open. FIG. 4(a) is a cross-sectional view taken along the line AA in FIG. 3(a). FIG. 4(b) is a cross-sectional view taken along the line AA in FIG. 3(b). In this embodiment, the front side of the image forming apparatus 1 is referred to as the front side, and the opposite side is referred to as the rear side. In other words, the Y direction in the drawings is referred to as the front-to-rear direction. The X direction, which is the horizontal direction perpendicular to the Y direction in the drawings, is also referred to as the left-to-right direction, and the Z direction, which is the vertical direction perpendicular to the X and Y directions in the drawings, is also referred to as the up-down direction.

[0025] As shown in FIGS. 2 to 4, the image forming apparatus 1 according to this embodiment includes a main body fixing portion 330 to which various components are fixed to the apparatus main body 1A, and the main body fixing portion 330 includes a main body frame 331 that serves as its skeleton. Also, as shown in FIGS. 4(a) and 4(b), the image forming apparatus 1 includes an inner door 320 as a first opening / closing portion and an outer door 310 as a second opening / closing portion. The inner door 320 is supported by the main body frame 331 of the apparatus main body 1A so as to be openable and closable, and the outer door 310 is supported by the main body frame 331 of the apparatus main body 1A so as to be openable and closable. That is, the image forming apparatus 1 has a double-door structure in which the outer door 310 and the inner door 320 are provided as a double door with respect to the main body fixing portion 330 of the apparatus main body 1A.

[0026] Of these, the inner door 320 is supported by a main body frame 331 of the apparatus main body 1A and is supported so as to be rotatable about a first rotation shaft 329 disposed outside the sheet passage area in each conveyance path. That is, the inner door 320 is rotatably moved between a first open position (see FIG. 4(a)) where it is open with respect to the apparatus main body 1A, and a first closed position (see FIG. 4(b)) where it is closed with respect to the apparatus main body 1A. In addition, the first rotation shaft 329 is disposed on the back side facing vertically. That is, the inner door 320 is rotatable horizontally and has a structure that allows the front side to be opened.

[0027] The outer door 310 is supported by a main body frame 331 of the apparatus main body 1A and is supported so as to be rotatable about a second rotation shaft 319 disposed outside the sheet passage area in each conveyance path. The second rotation shaft 319 is disposed parallel to the first rotation shaft 329. That is, the outer door 310 is rotatably moved between a second open position (see FIG. 4(a)) in which it is open relative to the apparatus main body 1A, and a second closed position (see FIG. 4(b)) in which it is closed relative to the apparatus main body 1A. The second rotation shaft 319 is disposed on the rear side facing vertically. That is, the outer door 310 is rotatable horizontally and can be opened from the front side.

[0028] As shown in FIG. 2(a), the reversing mechanism 300 is roughly composed of a part of a main body frame 331 of the main body fixing portion 330, a part of the inner door frame 321 of the inner door 320, and a part of the outer door frame 311 of the outer door 310. A first guide G1 arranged to face the inner door 320 and the outer door 310 is fixedly supported by the main body frame 331. In addition, a second guide G2 arranged to face the first guide G1 when the inner door 320 is in a first closed position where the inner door 320 is closed is fixedly supported by the inner door frame 321. The guide surface G1a of the first guide G1 and the guide surface G2a of the second guide G2 form the re-conveyance introduction path 383, which is a conveyance path along which the sheet is conveyed.

[0029] Furthermore, a third guide G3 disposed to face the outer door 310 is fixedly supported by the inner door frame 321. Furthermore, a fourth guide G4 disposed to face the third guide G3 and the first guide G1 is fixedly supported by the outer door frame 311 when the outer door 310 is in the second closed position where the outer door 310 is closed. The guide surface G1a of the first guide G1 and the guide surface G4a of the fourth guide G4 form the retreat path 382, ​​which is a conveyance path along which sheets are conveyed. Furthermore, the guide surface G3a of the third guide G3 and the guide surface G4a of the fourth guide G4 form the retreat introduction path 381, which is a conveyance path along which sheets are conveyed. Furthermore, the second switching unit 324 is supported by the inner door frame 321 of the inner door 320 so as to be switchable and movably supported. Further, a drive roller 335 of the second reversing roller pair 302 is disposed on the main body frame 331 of the apparatus main body 1A, and a driven roller 313 of the second reversing roller pair 302 is disposed on the outer door frame 311 of the outer door 310.

[0030] [Jam Clearance in Reversing Mechanism 300] If a sheet S jams (is jammed) in any of the evacuation introduction path 381, the evacuation path 382, ​​or the re-conveyance introduction path 383 in the reversing mechanism 300 configured as described above, a sensor (not shown) or the like detects the jam and notifies the user of the occurrence of the jam. The user then operates a handle (not shown) to unlock a lock mechanism 340 (see FIG. 4(a)), which will be described in detail later, and opens the outer door 310 and the inner door 320 (see FIG. 4(b)). As a result, as shown in FIG. 2(b), the evacuation introduction path 381, the evacuation path 382, ​​and the re-conveyance introduction path 383 are opened, and the jammed sheet S can be removed, that is, the jam can be cleared.

[0031] [Locking mechanism] Next, the locking mechanism 340 that locks the outer door 310 to the apparatus main body 1A will be described with reference to Figures 3 and 4. As shown in Figures 3(a), 3(b), 4(a), and 4(b), the locking mechanism 340 is configured to have a rotating shaft 341, bearings 342, 342, and hooks 343, 343. Meanwhile, the apparatus main body 1A is provided with hook portions 333, 333 as engaged portions that engage with the hooks 343, 343 of the locking mechanism 340.

[0032] In detail, the bearings 342, 342 are provided at two positions in the vertical direction so as to be fixed to the outer door 310 (outer door frame 311), and the rotating shaft 341 is rotatably supported by these bearings 342, 342. The hooks 343, 343 are fixed to the rotating shaft 341 at two positions in the vertical direction, and move with the rotation of the rotating shaft 341. As a result, the hooks 343, 343 can be switched between an engagement position where they engage with the hook portions 333, 333, respectively, and a release position where they release their engagement with the hook portions 333, 333.

[0033] As shown in FIGS. 3(a) and 4(a), the locking mechanism 340 is in an engaged position where the hooks 343 engage with the hook portions 333 in the second closed position when the outer door 310 is closed to the apparatus main body 1A. In other words, the locking mechanism 340 locks the outer door 310 to the apparatus main body 1A. From this position, for example, when a user operates a handle (not shown) drivingly connected to the rotating shaft 341, the rotating shaft 341 is rotated as shown in FIGS. 3(b) and 4(b), and the hooks 343 are switched to a release position where they are disengaged from the hook portions 333. This releases the lock between the outer door 310 and the apparatus main body 1A, allowing the outer door 310 to be opened from the apparatus main body 1A. At this time, the inner door 320 is also opened simultaneously with the outer door 310 by a biasing mechanism 350 (described later).

[0034] [Biasing mechanism] Next, the biasing mechanism 350 as a biasing part that biases the inner door 320 in the opening direction to be in the first closed position will be described with reference to Figures 3 and 5. Figure 5(a) is a cross-sectional view taken along the line BB in Figure 3(a). Figure 5(b) is a cross-sectional view taken along the line BB in Figure 3(b).

[0035] As described above, the image forming apparatus 1 has a double door structure having an outer door 310 and an inner door 320. Here, for example, if a sheet jams in the re-conveyance introduction path 383 located at the back of the inner door 320, there is a problem that the jam cannot be cleared unless the user notices the existence of the inner door 320. Therefore, in this embodiment, the biasing mechanism 350 is provided, and this problem is solved by automatically opening the inner door 320 when the outer door 310 is opened.

[0036] As shown in FIGS. 3(a) and 5(a), a positioning member 325 is fixed to the inner door 320. That is, the position of the positioning member 325 determines the position of the inner door 320. Meanwhile, the biasing mechanism 350 includes a movable shaft 351 and a spring 352 as a biasing member. The movable shaft 351 is disposed slidably and freely advancing and retreating relative to a main body hole 353 formed in the apparatus main body 1A. When the inner door 320 is in the first closed position when it is closed, the movable shaft 351 is inserted into and fitted into a fitting hole 325a formed in the positioning member 325, and the tip of the movable shaft 351 abuts against the bottom of the fitting hole 325a. That is, the spring 352 biases the inner door 320 in the opening direction via the movable shaft 351.

[0037] In other words, when the inner door 320 is in the first closed position in a closed state, the tip of the moving shaft 351 abuts against the bottom of the fitting hole 325a, and the biasing mechanism 350 biases the inner door 320 in an opening direction via the positioning member 325. Furthermore, as will be described in detail later, the positioning member 325 is positioned by the outer door 310 in a closed state so that the inner door 320 is in the first closed position. Therefore, when the locking mechanism 340 is released and the outer door 310 is opened as described above, the biasing mechanism 350 presses the inner door 320 in an opening direction via the positioning member 325, automatically opening the inner door 320. This allows the user to recognize the presence of the inner door 320 when opening the outer door 310, and particularly, when a sheet jams in the re-feed introduction path 383, the user can be made aware of the need to clear the jam.

[0038] [Inner door positioning] Next, the positioning of the inner door 320 in the first closed position by the locking mechanism 340 will be described with reference to Figures 3 and 5. If the positional accuracy of the inner door 320 in the first closed position when closed, that is, the positional accuracy of the second guide G2 relative to the first guide G1 (see Figure 2(a)), is poor, the accuracy of maintaining the spacing of the re-conveying introduction path 383 will be poor. This will result in an increase in jams in the re-conveying introduction path 383.

[0039] Here, it is conceivable that the position of the inner door 320 in the first closed position can be determined by sandwiching it between the outer door 310 and the device main body 1A when the outer door 310 is closed. However, the outer door 310 in the second closed position is locked to the device main body 1A by the locking mechanism 340, but is actually positioned relative to the device main body 1A via the locking mechanism 340. In other words, the outer door 310 is positioned relative to the device main body 1A via the hook 343, the rotating shaft 341, and the bearing 342. Because these component tolerances cause play, the positioning accuracy of the outer door 310 relative to the device main body 1A is not very good. Therefore, even if an attempt is made to position the inner door 320 using the outer door 310, the positioning accuracy of the inner door 320 is not very good. To address this issue, this embodiment employs a structure for positioning the inner door 320 as follows.

[0040] 3(a) and 5(a), a positioning member 325 is fixed to the front side of the inner door 320, opposite the first rotation shaft 329 in the front-rear direction (Y direction), and the positioning member 325 is biased in the direction of opening the inner door 320 by the biasing mechanism 350. When the outer door 310 and the inner door 320 are closed, the positioning member 325 abuts against the rotation shaft 341 of the locking mechanism 340; in other words, the inner door 320 is positioned in the apparatus main body 1A by the rotation shaft 341 of the locking mechanism 340.

[0041] Specifically, when the outer door 310 and the inner door 320 are closed, the hook 343 of the locking mechanism 340 engages with the hook portion 333 fixed to the device main body 1A. In this state, the biasing mechanism 350, in particular, causes the positioning member 325 to abut against the rotation shaft 341, biasing the rotation shaft 341 and the hook 343 in a direction away from the device main body 1A, thereby eliminating any play between the hook 343 and the hook portion 333. Therefore, the position of the rotation shaft 341 is accurately positioned relative to the device main body 1A, and the inner door 320 is accurately positioned by the positioning member 325, which abuts against and positions the rotation shaft 341. Therefore, the positioning accuracy between the second guide G2 of the inner door 320 and the first guide G1 of the device main body 1A is also improved, reducing the occurrence of jams in the re-conveyance introduction path 383. Furthermore, by positioning the inner door 320 with high precision, the positioning precision of the third guide G3 of the inner door 320 and the fourth guide G4 of the outer door 310 also improves, and the occurrence of jams in the evacuation introduction path 381 can also be reduced.

[0042] For example, when the positioning member 325 of the inner door 320 is brought into contact with the outer door 310, part tolerances cause play between the rotating shaft 341 and the bearing 342 and between the bearing 342 and the outer door 310 (outer door frame 311). This results in a decrease in the positioning accuracy of the inner door 320 compared to the structure of this embodiment.

[0043] However, simply abutting the positioning member 325 against the rotation shaft 341 may result in only being positioned with respect to the opening and closing direction (X direction, which is the left-right direction) of the inner door 320. Therefore, in this embodiment, a fitting hole 325a is formed in the positioning member 325, and the moving shaft 351, which slides relative to the main body hole 353 of the apparatus main body 1A when the inner door 320 is closed, is configured to fit into the fitting hole 325a.

[0044] 3(a) and 5(a), the moving shaft 351 of the urging mechanism 350 fits into a main body hole 353 of the apparatus main body 1A and slides, so that it is positioned in all directions except the axial direction (the direction of sliding movement). One of the positioning members 325 also has a fitting hole 325a, and the moving shaft 351 fits into the fitting hole 325a when the inner door 320 is closed. In other words, the moving shaft 351 is fitted as a pin between the main body hole 353 of the apparatus main body 1A and the fitting hole 325a of the positioning member 325 of the inner door 320, and positions the apparatus main body 1A and the inner door 320 in the front-to-rear direction (Y direction) and the up-down direction (Z direction). Therefore, as described above, the positioning member 325 is positioned in the left-right direction relative to the apparatus main body 1A by the rotation shaft 341 of the locking mechanism 340, and is positioned in the front-rear direction and the up-down direction by the biasing mechanism 350, that is, is positioned in all directions relative to the apparatus main body 1A. Therefore, when the outer door 310 is closed and locked to the apparatus main body 1A by the locking mechanism 340, the inner door 320 can be automatically positioned relative to the apparatus main body 1A.

[0045] [Possibilities for other embodiments] In the present embodiment described above, a sheet transport path (retraction introduction path 381 and retreat path 382) is formed between the outer door 310 and the inner door 320, but this is not limiting, and a transport path may be formed only between the inner door 320 and the device main body 1A.

[0046] Furthermore, in this embodiment, the double-door structure is described as being used in the reversing mechanism 300, but this is not limiting. For example, a structure in which a transport path for supplying sheets to the secondary transfer unit is formed between the inner door and the main body of the apparatus, and a transport path for re-transporting sheets during double-sided printing is formed between the inner door and the outer door, is also acceptable. In other words, the structure of this embodiment may be used in any part of an image forming apparatus that can employ a double-door structure. Furthermore, the present invention may be used in any device that can employ a double-door structure, such as a finisher device, bookbinding device, reversing device, inspection device, or hole punching device, as long as the double-door structure is applicable.

[0047] Furthermore, in this embodiment, the lock mechanism 340 has been described as being composed of a rotating shaft 341, a bearing 342, and a hook 343. However, the present invention is not limited to this, and a mechanism having a more complicated structure (components) may also be used. In this case, it is preferable to position the inner door 320 by abutting a component that engages with the apparatus main body 1A or a component fixed thereto against the inner door 320. Furthermore, in this embodiment, the present invention has been described as having two hooks, one at the top and one at the bottom, but the present invention is not limited to this, and the mechanism may have one hook or three or more hooks.

[0048] In addition, in this embodiment, the inner door 320 in the closed state is biased in the opening direction by the biasing mechanism 350. However, the present invention is not limited to this, and the inner door 320 may not be biased, and may be simply positioned relative to the apparatus main body 1A by the contact of the locking mechanism 340.

[0049] In addition, in this embodiment, the biasing mechanism 350 is described as being composed of the moving shaft 351 and the spring 352, but this is not limiting, and it is also possible to use, for example, a solenoid to press and bias the inner door 320, or to bias the inner door 320 by magnetic force.

[0050] Also, in this embodiment, the positioning member 325 is fixed to the inner door 320, and is brought into contact with the locking mechanism 340 or is urged by the urging mechanism 350. However, this is not limiting, and the inner door frame 321 may be brought into contact with the locking mechanism 340 or may be urged by the urging mechanism 350. Furthermore, the inner door 320 may be provided with two positioning members: one positioning member that the locking mechanism 340 abuts against, and one positioning member that is urged by the urging mechanism 350.

[0051] Furthermore, in this embodiment, the outer door 310 and the inner door 320 are described as rotating around the second rotating shaft 319 and the first rotating shaft 329 as the rotation fulcrum. However, the outer door 310 and / or the inner door 320 are not limited to this, and may be opened and closed like a sliding door, opened and closed like a shutter, or opened like a double door, that is, any structure may be used as long as it is a double door structure.

[0052] In addition, in this embodiment, the positioning member 325 is positioned in the Y and Z directions by forming a fitting hole 325a in the positioning member 325 and fitting the moving shaft 351 therein. However, the present invention is not limited to this, and the positioning member 325 may be configured to simply come into contact with the moving shaft 351 and be biased in one direction in the X direction. In this case, the alignment of the inner door 320 and the apparatus main body 1A in the Y and Z directions may be achieved by providing, for example, a protrusion and a hole that fits thereto in another portion. [Explanation of symbols]

[0053] 1...image forming apparatus (sheet conveying apparatus) / 1A...apparatus main body / 1D...image forming unit / 310...outer door (second opening / closing section) / 319...second rotating shaft / 320...inner door (first opening / closing section) / 325...positioning member / 325a...fitting hole / 329...first rotating shaft / 333...hook portion (engaged portion) / 340...locking mechanism / 341...rotating shaft / 342...bearing / 343...hook / 350...urging mechanism (urging portion) / 351...moving shaft / 352...spring (urging member) / 381...retreat introduction path (conveying path) / 383...re-conveying introduction path (conveying path) / G1...first guide / G2...second guide / G3...third guide / G4...fourth guide

Claims

1. a device body having a first guide; a first opening / closing unit that is supported by the apparatus body so as to be openable and closable, and that has a second guide that, when closed, faces the first guide and forms a conveyance path along which a sheet is conveyed; a second opening / closing unit that is supported on the device body so as to be openable and closable and that covers the first opening / closing unit in a closed state; an engaged portion provided on the device body; a locking mechanism supported by the second opening / closing unit, and configured to lock the second opening / closing unit to the device body by engaging with the engaged portion when the second opening / closing unit is in a closed state; the first opening / closing unit is positioned by contacting the locking mechanism when the second opening / closing unit is closed; A sheet conveying device characterized by:

2. the first opening / closing portion has a third guide, the second opening / closing unit has a fourth guide that faces the third guide when closed and forms a conveyance path along which a sheet is conveyed; 2. The sheet transport device according to claim 1.

3. a biasing portion that biases the first opening / closing portion in a direction to open the first opening / closing portion when the first opening / closing portion is in a closed state; When the locking mechanism is released and the second opening / closing unit is opened, the first opening / closing unit is biased by the biasing unit and opens.

2. The sheet transport device according to claim 1.

4. the first opening / closing unit has a positioning member that is biased by contact with the biasing portion in a closed state and is positioned by contact with the locking mechanism; 4. The sheet transport device according to claim 3.

5. the biasing portion has a moving shaft that is slidable relative to the device body and a biasing member that biases the moving shaft, the positioning member has a fitting hole that fits onto the moving shaft when the first opening / closing unit is closed; 5. The sheet transport device according to claim 4.

6. The locking mechanism is a bearing provided in the second opening / closing portion; a rotating shaft rotatably supported by the bearing; a hook that is fixed to the rotary shaft and moves with rotation of the rotary shaft, thereby being switched between an engagement position where it engages with the engaged portion and a release position where it releases the engagement with the engaged portion; the first opening / closing unit is positioned by contacting the rotation shaft when the second opening / closing unit is closed; 2. The sheet transport device according to claim 1.

7. the first opening / closing unit is supported rotatably about a first rotation axis relative to the device body, the second opening / closing unit is supported rotatably with respect to the device body around a second rotation axis that is arranged parallel to the first rotation axis; 2. The sheet transport device according to claim 1.

8. The first rotation shaft and the second rotation shaft are arranged on the rear side of the device body and facing in a vertical direction.

8. The sheet transport device according to claim 7.

9. an image forming unit that forms an image on a sheet; 9. The sheet transport device according to claim 1, wherein the sheet transport device is a sheet conveying device.

Images