SHEET STORAGE DEVICE AND IMAGE FORMING SYSTEM INCLUDING SHEET STORAGE DEVICE

Abstract

To provide a sheet storage device capable of suppressing deflection of a pulley and suppressing defective feeding.SOLUTION: A sheet storage device includes a body housing, a sheet placement tray, a shaft, a plurality of pulleys, a plurality of wires, a driving device, a regulation part and an urging member. The sheet placement tray is supported in the body housing so as to be able to move up and down, and the sheets are placed thereon. The shaft is supported by the body housing so as to be rotatable in both forward and reverse directions. The pulley is externally fitted on both ends of a rotary axis of the shaft and attached with play in a direction of the rotary axis. The wire has one end fixed to the pulley and the other end fixed to the sheet placement tray to suspend the sheet placement tray. A driving device rotates the shaft. The regulation part regulates the movement of the pulley in an axial direction. The urging member urges each pulley toward the regulation part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sheet storage device and an image forming system including the sheet storage device. [Background technology]

[0002] In image forming devices such as copiers, printers, and facsimiles, when one image forming device is shared by many users, the amount of sheets (recording media including printing paper and envelopes) consumed per image forming device increases. Generally, the number of sheets that can be stored inside the main body of an image forming device is about several hundred sheets, so that sheets need to be frequently replenished. Therefore, Patent Document 1 discloses an image forming system in which a large-capacity sheet storage device capable of storing several thousand sheets is attached to the side of the image forming device, and sheets are fed from the sheet storage device to the image forming device.

[0003] The sheet storage device of Patent Document 1 includes a sheet stacking tray on which sheets are stacked, a hanging mechanism that suspends the sheet stacking tray, and a drive device that applies a rotational driving force to the hanging mechanism to raise and lower the sheet stacking tray. The hanging mechanism includes a shaft supported so as to be rotatable in both forward and reverse directions, multiple pulleys attached to both ends of the shaft in the direction of the rotation axis, and four wires, one end of which is fixed to the pulley and the other end of which is fixed to the sheet stacking tray.

[0004] The drive device is connected to the shaft and applies a rotational drive force to the shaft to rotate it. The pulley is prevented from rotating relative to the shaft and rotates integrally with the shaft. The drive device rotates the shaft and the pulley to wind the wire around the pulley and unwind it from the pulley, thereby raising and lowering the sheet stacking tray.

[0005] A sheet feeding section that feeds sheets from the sheet storage device to the image forming apparatus is disposed above the sheet stacking tray. When the sheet stacking tray is raised and the top surface of the sheet stack stacked on the sheet stacking tray comes into contact with the sheet feeding section, the sheet feeding section feeds the sheet in contact with the sheet to the image forming apparatus.

[0006] The pulley of such a sheet storage device is fitted onto a shaft, and is positioned so that its axial movement with respect to the shaft is restricted. For positioning, a positioning member such as a parallel pin that is removably provided so as to penetrate the shaft is used. The positioning member is inserted into the shaft member so as to face the side surface of the pulley in the axial direction. When the shaft moves in the axial direction, it comes into contact with the positioning member, and the axial movement is restricted. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2020-33161 A Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, each pulley is attached to the shaft with some slack (backlash) in the axial direction (a gap between the pulley and the positioning member) in consideration of ease of assembly. For this reason, during operation of the sheet storage device, each pulley may move in the axial direction due to, for example, vibrations caused by the operation of the drive device or the sheet feeding unit. When the pulley moves in the axial direction, the winding position of the wire relative to the pulley is displaced in the axial direction. When the pulley rotates in this state in the direction of winding the wire, the wire is wound around the pulley so as to ride on top of the wire already wound around the pulley, and is wound around the pulley in a multi-layered state. Then, the wire may get tangled during unwinding or winding, preventing the sheet stacking tray from rising and falling, or the amount of wire unwound from the pulley may change, causing the sheet stacking tray to tilt, resulting in a so-called feeding failure in which sheets are not fed normally.

[0009] The present invention has an object to provide a sheet storage device capable of suppressing deviation of the winding position of the wire caused by axial movement of the pulley, thereby suppressing feeding failure. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a sheet storage device including a main housing, a sheet stacking tray, a shaft, a plurality of pulleys, a plurality of wires, a drive device, a regulating portion, and an urging member. The sheet stacking tray is supported in the main housing so as to be movable up and down, and sheets are stacked on the sheet stacking tray. The shaft is supported in the main housing so as to be rotatable in both forward and reverse directions. The pulleys are fitted onto both ends of the rotation axis of the shaft and attached with a play in the direction of the rotation axis. The wire has one end fixed to the pulley and the other end fixed to the sheet stacking tray to suspend the sheet stacking tray. The drive device rotates the shaft. The regulating portion regulates the axial movement of the pulley. The urging member urges each pulley toward the regulating portion. Effect of the Invention

[0011] According to the configuration of the present invention, the pulley is biased toward the regulating portion by the biasing member and abuts against the regulating portion in the axial direction. The axial movement of the pulley is restricted by the biasing force of the biasing member. Therefore, the winding position of the wire with respect to the pulley is less likely to deviate in the axial direction, and the wire can be prevented from being wound around the pulley so as to ride up on top of the wire already wound around the pulley. This makes it easier for the wire to be smoothly wound in the axial direction, and the wire is less likely to become tangled or the amount of wire payout to change. Therefore, it is possible to provide a sheet storage device that can suppress sheet feeding failures. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an image forming system 100 including a sheet storage device 20 according to an embodiment of the present invention and an image forming apparatus 1. [Diagram 2] FIG. 2 is a perspective view showing the internal configuration of the main body housing 26 of the sheet storage device 20. [Diagram 3] 3 is a front view of the sheet stacking tray 27 shown in FIG. 2 from above; [Figure 4] FIG. 2 is a perspective view showing the periphery of the rear pulley 72. [Diagram 5] FIG. 2 is a plan view showing the periphery of the end portion on one side (the rear side of the main body housing 26) of the shaft 35. [Figure 6] FIG. 3 is a cross-sectional view showing the periphery of the restricting portion 64a. [Figure 7] FIG. 11 is a cross-sectional view showing another example of the regulating portion 64 of the sheet storage device 20 according to the present invention. [Figure 8] FIG. 11 is a cross-sectional view showing another example of the regulating portion 64 of the sheet storage device 20 according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a sheet storage device 20 according to an embodiment of the present invention and an image forming system 100 including the sheet storage device 20 will be described with reference to the drawings.

[0014] 1 is a schematic cross-sectional view showing a schematic configuration of an image forming system 100 including a sheet storage device 20 according to an embodiment of the present invention and an image forming apparatus 1. The image forming apparatus 1 includes a paper feed section 2 arranged at a lower portion thereof, a sheet conveying section 3 arranged at a side of the paper feed section 2, an image forming section 4 arranged above the sheet conveying section 3, a fixing device 5 arranged on the discharge side of the image forming section 4, and an image reading section 6 arranged above the image forming section 4 and the fixing device 5.

[0015] The paper feed section 2 includes a plurality of paper feed cassettes 7 that store sheets P, which are plain paper, and the rotation of a paper feed roller 8 reliably sends out the sheets P one by one from a selected one of the plurality of paper feed cassettes 7 to the sheet transport section 3.

[0016] Manual feed tray 25 holds sheets P such as plain paper of a size different from the sheets P stored in paper feed cassette 7, or OHP sheets or envelopes, and sends out sheets P such as OHP sheets or envelopes to sheet transport section 3.

[0017] The sheet P sent to the sheet conveying unit 3 is conveyed toward the image forming unit 4 via a sheet feeding path 10. The sheet feeding path 10 extends upward from each paper feed cassette 7, and merges with a junction path 52 connected to a sheet discharge port 51 of a sheet storage device 20 (described later) at a midpoint.

[0018] The image forming unit 4 forms a toner image on a sheet P by an electrophotographic process, and includes a photoconductor 11 supported on a shaft so as to be rotatable in the direction of the arrow in FIG. 1, and arranged around the photoconductor 11 in the direction of rotation are a charging unit 12, an exposure unit 13, a developing device 14, a transfer unit 15, a cleaning unit 16, and a charge removal unit 17.

[0019] The charging section 12 is equipped with a charging wire to which a high voltage is applied, and when a predetermined potential is applied to the surface of the photoconductor 11 by corona discharge from this charging wire, the surface of the photoconductor 11 is uniformly charged. When the photoconductor 11 is irradiated with light based on the image data of the document read by the image reading section 6 by the exposure section 13, the surface potential of the photoconductor 11 is selectively attenuated, and an electrostatic latent image is formed on the surface of the photoconductor 11.

[0020] Next, the developing unit 14 develops the electrostatic latent image on the surface of the photoreceptor 11, and a toner image is formed on the surface of the photoreceptor 11. This toner image is transferred by the transfer unit 15 to a sheet P supplied between the photoreceptor 11 and the transfer unit 15.

[0021] The sheet P onto which the toner image has been transferred is transported toward the fixing device 5 disposed downstream in the sheet transport direction of the image forming unit 4. In the fixing device 5, the sheet P is heated and pressurized by a heating roller 18 and a pressure roller 19, and the toner image is melted and fixed onto the sheet P. Next, the sheet P onto which the toner image has been fixed is discharged onto a discharge tray 21 by a pair of discharge rollers 22.

[0022] After transfer by transfer unit 15, the toner remaining on the surface of photoconductor 11 is removed by cleaning unit 16, and the residual charge on the surface of photoconductor 11 is removed by charge removal unit 17. Then, photoconductor 11 is charged again by charging unit 12, and image formation is performed in the same manner.

[0023] A large-capacity sheet storage device 20 capable of storing several thousand sheets P is disposed adjacent to the side of the image forming apparatus 1. The sheet storage device 20 accommodates a sheet stacking tray 27, a hanging mechanism 60, wires 29a to 29d, a driving device 30, and a sheet feeding mechanism 32 inside a main body housing 26 that forms the case of the sheet storage device 20. The main body housing 26 is formed in a substantially rectangular parallelepiped shape, and a plurality of casters 24 are attached to the bottom surface of the main body housing 26 so that the sheet storage device 20 can be easily moved.

[0024] FIG. 2 is a perspective view showing the internal configuration of the main body housing 26 of the sheet storage device 20. FIG. 3 is a front view showing the sheet stacking tray 27 shown in FIG. 2 from above. The side surface of the main body housing 26 on the right rear side of the paper shown in FIG. 2 is the side surface on the front side (front side of the image forming apparatus 1) in the paper direction shown in FIG. 1. The side surface of the main body housing 26 on the left front side of the paper shown in FIG. 2 is the side surface on the rear side (front side of the image forming apparatus 1) in the paper direction in FIG. 1. The width direction of the sheets P stored in the sheet storage device 20 is the same as the direction from the front to the rear of the main body housing 26 (the left-right direction shown in FIG. 3).

[0025] 2 and 3, the sheet stacking tray 27 includes a tray portion 33, which is a rectangular plate-like body extending parallel to a horizontal plane, and fixed portions 34 that protrude outward in the width direction (width direction of the sheets P) from the four corners of the tray portion 33, and is supported in the main housing 26 so as to be movable up and down in the vertical direction (the direction of the arrow Y shown in FIG. 2). The sheets P are stacked in the center of the tray portion 33 (the position shown by the dashed line in FIG. 3).

[0026] The hanging mechanism 60 suspends the sheet stacking tray 27 via a plurality of (four in this example) wires 29a to 29d (first wire 29a, second wire 29b, third wire 29c, fourth wire 29d) so that the sheet stacking tray 27 can be raised and lowered within the main housing 26. The hanging mechanism 60 includes a shaft 35, a plurality of pulleys 72, 73 (rear pulley 72, front pulley 73), a biasing member 63, and pulleys 41a to 41f.

[0027] The shaft 35 extends along a horizontal direction (width direction of the sheet P) perpendicular to the lifting direction of the sheet stacking tray 27. The shaft 35 is supported inside the main body housing 26 so as to be rotatable in both forward and reverse directions (both clockwise and counterclockwise directions with the central axis of the shaft 35 as the rotation axis). A rear pulley 72 is fitted and attached to an end of one side (the rear side of the main body housing 26) of the shaft 35 in the direction along the rotation axis of the shaft 35 (hereinafter referred to as the "axial direction"). A front pulley 73 is fitted and attached to an end of the other side in the axial direction (the opposite side to the one side (the front side of the main body housing 26)). The rear pulley 72 and the front pulley 73 are slidable along the axial direction relative to the shaft. The rear pulley 72 and the front pulley 73 are connected to the shaft 35 by a connecting mechanism 71 described later, with a gap (backlash) that allows them to move in the axial direction.

[0028] The rear pulley 72 is located on the rear side of the image forming apparatus 1, and the front pulley 73 is located on the front side of the image forming apparatus 1 (see FIG. 2). As shown in FIG. 3, the rear pulley 72 is composed of a first pulley 28a and a second pulley 28b adjacent to each other in the axial direction. The front pulley 73 is composed of a third pulley 28c and a fourth pulley 28d adjacent to each other in the axial direction. The first pulley 28a is located on the outside of the second pulley 28b in the axial direction. The third pulley 28c is located on the outside of the fourth pulley 28d in the axial direction. The first pulley 28a is bonded to the second pulley 28b in the axial direction, and they rotate together. Similarly, the third pulley 28c and the fourth pulley 28d are bonded to each other in the axial direction, and they rotate together.

[0029] One end of a first wire 29a is fixed to the first pulley 28a. One end of a second wire 29b is fixed to the second pulley 28b. One end of a third wire 29c is fixed to the third pulley 28c. One end of a fourth wire 29d is fixed to the fourth pulley 28d. When each of the pulleys 28a to 28d rotates in the forward direction, each of the wires 29a to 29d fixed to each of the pulleys is wound up. Conversely, when each of the pulleys 28a to 28d rotates in the reverse direction, each of the wires 29a to 29d fixed to each of the pulleys 28a to 28d is paid out.

[0030] Fig. 4 is a perspective view showing the periphery of the rear side pulley 72. Fig. 5 is a plan view showing the periphery of the end portion on one side (the rear side of the main body housing 26) of the shaft 35. Fig. 6 is a cross-sectional view showing the periphery of the key 64. Since the rear side pulley 72 and the front side pulley 73 have the same shape and the same configuration, only the rear side pulley 72 will be described in detail here, and the front side pulley 73 will be given the same reference numeral and description thereof will be omitted.

[0031] 4, 5, and 6, the rear pulley 72 includes an outer flange 39a formed on an axially outer end face of the first pulley 28a, an inner flange 39b formed on an axially inner end face of the second pulley 28b, and an intermediate flange 39c formed in the axial center of the rear pulley 72. The outer flange 39a, the inner flange 39b, and the intermediate flange 39c are flanges that extend along the radial direction.

[0032] A first winding portion 38a and a second winding portion 38b are formed adjacent to each other in the axial direction on the outer peripheral surface of the back pulley 72. The first winding portion 38a is located between the outer flange 39a and the intermediate flange 39c in the axial direction. The second winding portion 38b is located between the intermediate flange 39c and the inner flange 39b in the axial direction. The outer diameters of the first winding portion 38a and the second winding portion 38b are tapered so as to become larger toward one side in the axial direction (the outer side in the axial direction) (see FIG. 5).

[0033] As shown in FIG. 4, a locking groove 47 for locking the end of the first wire 29a is formed in the intermediate flange 39c of the back side pulley 72. The locking groove 47 includes a locking hole 48 that is recessed in a square shape from the axially inner end face of the intermediate flange 39c to the axially outer side, and a notch portion 49 that extends radially from the locking hole 48 to reach the outer circumferential surface of the inner flange 39b. Here, a spherical hook portion 50 is formed at one end of the first wire 29a. The width, length, and depth of the locking hole 48 are larger than the diameter of the hook portion 50. The locking hole 48 is capable of housing the hook portion 50. The width of the notch portion 49 is narrower than the diameter of the hook portion 50 and wider than the thickness of the first wire 29a. The hook portion 50 is housed in the locking hole 48, and the first wire 29a is housed in the notch portion 49.

[0034] Since the width of the notch 49 is narrower than the diameter of the hook 50, even if the first wire 29a is pulled in the direction of the end opposite to the hook 50, the hook 50 gets caught on the inner wall of the locking hole 48 and cannot pass through the notch 49. This makes it possible to prevent one end of the first wire 29a from slipping out of the locking groove 47. Similarly, the inner flange 39b is also formed with a locking groove 47, which locks the end of the second wire 29b.

[0035] The rear side pulley 72 winds up the wires 29a, 29b by winding the first wire 29a around the outer circumferential surface of the first winding portion 38a and the second wire 29b around the outer circumferential surface of the second winding portion 38b. The first wire 29a and the second wire 29b are wound onto the rear side pulley 72 when the rear side pulley 72 rotates in the forward direction, and are unwound from the rear side pulley 72 when the rear side pulley 72 rotates in the reverse direction.

[0036] The hook portion 50 may be configured to be press-fitted into the locking hole 48 and fixed thereto. Alternatively, the hook portion 50 may be adhered to the locking hole 48 with an adhesive or the like. Alternatively, the rear pulley 72 may include a plurality of lids that cover the end faces of the inner flange 39b and the intermediate flange 39c, and the hook portion 50 may be secured to the locking hole 48 by the lids.

[0037] As shown in Figures 4, 5 and 6, a key 64 is provided on the shaft 35 outside the back pulley 72 in the axial direction. An axial keyway 65 is formed in the outer circumferential surface of the shaft 35, recessed radially inward. The key 64 is a key body inserted into the axial keyway 65 with a tightening margin. The key 64 has a restricting portion 64a formed on the inner side surface in the axial direction. Note that a so-called D-cut surface formed in a surface parallel to the axial direction may be formed at a location on the outer circumferential surface of the shaft 35 that overlaps with the axial keyway 65.

[0038] In the radial center of the back side pulley 72, there are formed an axial hole 66 penetrating the back side pulley 72 in the axial direction, and a pulley side key groove 67 recessed in the radial direction from the axial hole 66. The pulley side key groove 67 is a groove formed to be able to accommodate the key 64. The pulley side key groove 67 opens on the axially outer end face of the first pulley 28a (the side face of the back side pulley 72) and extends inward in the axial direction. The width of the pulley side key groove 67 (the distance between the inner wall faces facing each other in the circumferential direction) is slightly larger than the width of the key 64 (the length along the circumferential direction). The depth (radial length) of the pulley side key groove 67 is slightly larger than the protruding amount of the key 64 (the distance from the outer circumferential surface of the shaft 35 to the end of the key 64 in the protruding direction).

[0039] A support wall portion 69 (opposing portion) is provided on the shaft 35 at a portion inside the back side pulley 72 in the axial direction. The support wall portion 69 has a flange shape extending radially from the outer circumferential surface of the shaft 35, and rotates integrally with the shaft 35. The support wall portion 69 may be configured to include a groove portion (not shown) formed on the outer circumferential surface of the shaft 35 and a retaining ring such as a C-ring or an E-ring fitted into the groove portion. A biasing member 63 is disposed between the back side pulley 72 and the support wall portion 69 in the axial direction. The biasing member 63 is a coil spring fitted onto the shaft 35, and both ends of the biasing member 63 are in contact with the back side pulley 72 (the second pulley 28b) and the support wall portion 69, biasing the back side pulley 72 (the second pulley 28b and the first pulley 28a) outward in the axial direction.

[0040] Here, the connecting mechanism 71 is composed of the shaft side keyway 65, the pulley side keyway 67, and the key 64. As described above, the back side pulley 72 is attached to the shaft 35 by the connecting mechanism 71 in a state with some backlash in the axial direction (a state in which a gap that allows movement in the axial direction is provided). Specifically, the pulley side keyway 67 and the key 64 inserted into the shaft side keyway 65 overlap in the circumferential direction of the shaft 35, and the key 64, inserted into the shaft side keyway 65, is fitted into the pulley side keyway 67 via a gap.

[0041] The biasing member 63 biases the first pulley 28a together with the second pulley 28b outward in the axial direction (biases the backside pulley 72 outward in the axial direction, i.e., toward the key 64). As a result, the restricting portion 64a of the key 64 comes into axial contact with the inner wall surface 67a on the axially inner side of the pulley side key groove 67, restricting the axial movement of the backside pulley 72. Also, when the shaft 35 rotates around the rotation axis, the circumferential side surface of the key 64 comes into circumferential contact with the inner wall surface of the pulley side key groove 67. As a result, the circumferential movement of the shaft 35 and the backside pulley 72 is restricted (stopped). Therefore, the backside pulley 72 rotates integrally with the shaft 35.

[0042] Returning to Figs. 1, 2 and 3, the driving device 30 is connected to one end of the shaft 35 in the axial direction. The driving device 30 is located axially outward of the rear pulley 72 of the shaft 35. The driving device 30 includes a driving unit M such as a motor capable of applying a rotational driving force, and a driving input gear 31 connected to the driving unit M and the shaft 35. The driving input gear 31 is composed of a plurality of gears, and is connected to the shaft 35 via a coupling member (not shown). The driving input gear 31 transmits the rotational driving force of the driving unit M to the shaft 35. The driving device 30 generates a rotational driving force in the forward or reverse direction by the driving unit M, and rotates the shaft 35 in the forward or reverse direction via the driving input gear 31.

[0043] As described above, one end of the first wire 29a and the second wire 29b is fixed to the rear pulley 72. In addition, one end of the third wire 29c and the fourth wire 29d is fixed to the front pulley 73.

[0044] The other end of each of the wires 29a to 29d is fixed to a respective fixed portion 34 of the sheet stacking tray 27. Specifically, the other end of the first wire 29a (the end opposite to the end fixed to the rear pulley 72) and the other end of the second wire 29b (the end opposite to the end fixed to the rear pulley 72) are fixed to a fixed portion 34 located on the rear side of the main body housing 26. The other end of the first wire 29a is fixed to a fixed portion 34 on the side closer to the rear pulley 72 (the side farther from the image forming apparatus 1) than the other end of the second wire 29b.

[0045] The other end of the third wire 29c (the end opposite to the end fixed to the front pulley 73) and the other end of the fourth wire 29d (the end opposite to the end fixed to the front pulley 73) are fixed to a fixing portion 34 located on the front side of the main body housing 26. The other end of the third wire 29c is fixed to a fixing portion 34 on the side closer to the front pulley 73 (the side farther from the image forming apparatus 1) than the other end of the fourth wire 29d.

[0046] Pulleys 41a to 41f are disposed between one end and the other end of each of the wires 29a to 29d. The wires 29a to 29d suspend the sheet stacking tray 27 via the pulleys 41a to 41f.

[0047] The pulleys 41a to 41f are rotatably arranged at positions above the rear pulley 72 and the front pulley 73 (see FIG. 2). The pulleys 41a to 41c are arranged on one side of the tray portion 33 of the sheet stacking tray 27 in the axial direction (the rear side of the main body housing 26), and the pulleys 41d to 41f are arranged on the other side of the tray portion 33 of the sheet stacking tray 27 in the axial direction (the front side of the main body housing 26).

[0048] The first wire 29a extends upward from the rear pulley 72, is hooked to a pulley 41a, and extends vertically downward from the pulley 41a to suspend the sheet stacking tray 27. The second wire 29b extends upward from the rear pulley 72, is hooked to a pulley 41b, extends horizontally from the pulley 41b toward the upstream side in the sheet conveying direction, is hooked to a pulley 41c that is farther from the rear pulley 72 than the pulley 41b, and extends vertically downward from the pulley 41c to suspend the sheet stacking tray 27.

[0049] The third wire 29c extends upward from the front pulley 73, is hooked to a pulley 41d, and extends vertically downward from the pulley 41d to suspend the sheet stacking tray 27. The fourth wire 29d extends upward from the front pulley 73, is hooked to a pulley 41e, extends horizontally from the pulley 41e toward the upstream side in the sheet conveying direction, is hooked to a pulley 41f that is farther from the front pulley 73 than the pulley 41e, and extends vertically downward from the pulley 41f to suspend the sheet stacking tray 27.

[0050] When the drive device 30 rotates the shaft 35 in the forward direction, the rear side pulley 72 and the front side pulley 73 rotate in the forward direction. Then, the wires 29a to 29d are wound around the rear side pulley 72 and the front side pulley 73, and the sheet stacking tray 27 moves up. Conversely, when the drive device 30 rotates the shaft 35 in the reverse direction, the rear side pulley 72 and the front side pulley 73 rotate in the reverse direction. Then, the wires 29a to 29d are unwound from the rear side pulley 72 and the front side pulley 73, and the sheet stacking tray 27 moves down.

[0051] Returning to FIG. 1, a sheet feeding mechanism 32 that feeds a sheet P downstream in the sheet transport direction is disposed in the upper portion of the main body housing 26. The sheet feeding mechanism 32 includes a pickup roller 53, a pair of paper feed rollers 54, a pair of transport rollers 62, and a sheet discharge port 51. The pickup roller 53 is located above the sheet stacking tray 27, and is in a position to come into contact with the upper surfaces of the stacked sheets P when the sheet stacking tray 27 rises. When the pickup roller 53 rotates in the feeding direction (clockwise direction in FIG. 1) while in contact with the upper surfaces of the sheets P, the uppermost sheet P in the stack of sheets P is fed.

[0052] The pair of feed rollers 54 is disposed opposite the pair of feed rollers 54 on the downstream side in the sheet conveying direction. The pair of conveying rollers 62 is disposed opposite the pair of feed rollers 54 on the downstream side in the sheet conveying direction. The sheet discharge port 51 is located at the downstream end of the sheet feeding mechanism 32 in the sheet conveying direction and opens on the side of the main housing 26. The sheet P fed downstream by the pickup roller 53 is further conveyed downstream by the pair of feed rollers 54 and the pair of conveying rollers 62, and is discharged to the outside of the sheet storage device 20 through the sheet discharge port 51. As described above, the junction path 52 of the image forming device 1 is connected to the sheet discharge port 51. Therefore, the sheet P discharged from the sheet discharge port 51 is carried into the sheet feeding path 10 through the junction path 52, and is conveyed to the image forming unit 4 in the image forming device 1, where image formation is performed as described above.

[0053] According to the configuration of the sheet storage device 20 according to the embodiment, the rear pulley 72 and the front pulley 73 abut against the restricting portion 64a of the key 64 in the axial direction and are biased toward the key 64 by the biasing member 63. The rear pulley 72 and the front pulley 73 are restricted in their axial movement by the biasing force of the biasing member 63. Therefore, the winding positions of the wires 29a to 29d relative to the rear pulley 72 and the front pulley 73 are less likely to deviate in the axial direction, and the wires 29a to 29d can be prevented from being wound around the rear pulley 72 and the front pulley 73 so as to ride on the wires 29a to 29d already wound around the rear pulley 72 and the front pulley 73. This makes it easier for the wires 29a to 29d to be smoothly wound in the axial direction, making it less likely for the wires 29a to 29d to become entangled or for the amount of the wires 29a to 29d to be unwound to change. Therefore, it is possible to provide the sheet storage device 20 capable of suppressing sheet feeding failure.

[0054] As described above, the outer diameters of the first winding portion 38a and the second winding portion 38b are tapered so that they become larger toward one side in the axial direction (the outside in the axial direction). Therefore, when the wires 29a to 29d are wound around the first winding portion 38a and the second winding portion 38b of the rear pulley 72 and the front pulley 73, the wires 29a to 29d are wound sequentially from the inner end of the winding portion 38 in the axial direction. Therefore, the wires 29a to 29d are wound more smoothly from the inner end to the outer end of the winding portion 38 in the axial direction, and are less likely to become entangled.

[0055] In addition, the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. For example, the pulley side key groove 67 is formed in the back side pulley 72 and the front side pulley 73, and the key 64 is fitted into the pulley side key groove 67, but the present invention is not limited to this. For example, as shown in FIG. 7, a configuration can be adopted in which the pulley side key groove 67 is not formed, and an annular regulating member 74 is fixed to the shaft 35 instead of the key 64. The regulating member 74 is an annular retaining ring such as a C ring or an E ring, and is fitted into a groove (not shown) formed on the outer circumferential surface of the shaft 35 and fixed to the shaft 35. In this case, the inner end surface in the axial direction of the regulating member 74 becomes the regulating portion 64a. The regulating portion 64a faces the outer end surface in the axial direction of the back side pulley 72. When the rear side pulley 72 is biased by the biasing member 63, the restricting portion 64a comes into contact with the axially outer end face of the rear side pulley 72, and the axial movement of the rear side pulley 72 is restricted.

[0056] Also, instead of the restricting member 74, a configuration can be adopted in which the axial movement of the rear side pulley 72 and the front side pulley 73 is restricted by an inner wall formed at a predetermined location of the main housing 26 (not shown). The inner wall is formed in a rib shape extending from a predetermined location inside the main housing 26 toward the shaft 35. The inner wall is provided on the outer side of the rear side pulley 72 in the axial direction and on the outer side of the front side pulley 73 in the axial direction, and faces the outer end faces of the rear side pulley 72 and the front side pulley 73 in the axial direction, respectively.

[0057] In addition, although the support wall portion 69 is provided on the shaft 35, for example, as shown in FIG. 8, a configuration including a side wall 70 formed in a rib shape extending from a predetermined position inside the main housing 26 toward the shaft 35 can be adopted instead of the support wall portion 69. The side wall 70 is a rib-shaped wall formed to span between the inner wall surfaces (not shown) of the main housing 26. The side wall 70 is provided on the axial inner side of the back side pulley 72 (see FIG. 8) and the axial inner side of the front side pulley 73 (not shown). Each side wall 70 faces the axial inner end faces of the back side pulley 72 and the front side pulley 73. In this case, the side wall 70 is separated from the shaft 35, and since the side wall 70 is fixed to the main housing 26, even if the shaft 35 is displaced in the axial direction due to vibration or the like, the urging member 63, the back side pulley 72, and the front side pulley 73 that are in contact with the side wall 70 are more unlikely to move in the axial direction. Also, the shaft 35 may be rotatably supported by the side wall 70 via a bearing or the like.

[0058] In addition, the first pulley 28a and the second pulley 28b, and the third pulley 28c and the fourth pulley 28d may not be glued to each other, but may be individually prevented from rotating relative to the shaft 35 so as to be rotatable integrally with the shaft 35. [Industrial Applicability]

[0059] The present invention can be used in a large-capacity sheet storage device capable of storing sheets to be supplied to an image forming apparatus, and by using the present invention, it is possible to suppress failure in feeding sheets from the sheet storage device to the image forming apparatus. [Explanation of symbols]

[0060] 1. Image forming device 4. Image forming section 20. Seat storage device 26 Main body housing 27 Sheet loading tray 72, 73 Pulley 29a~29d Wire 30 Drive unit 32 Sheet feeding mechanism 35 Shaft 38 Winding section 38a First winding section 38b Second winding section 63 Pressing member 64 Key 64a Regulatory Department 69 Support wall part (opposing part) 70 side wall 100 Image forming system P-sheet

Claims

1. A main body housing; a sheet stacking tray supported within the main body housing so as to be capable of being raised and lowered, on which sheets are stacked; a shaft supported by the main body housing so as to be rotatable in both forward and reverse directions; A plurality of pulleys are fitted to both ends of the shaft in the rotation axis direction and are attached with a play in the rotation axis direction; a plurality of wires each having one end fixed to the pulley and the other end fixed to the sheet stacking tray for suspending the sheet stacking tray; A drive unit for rotating the shaft; a restricting portion that restricts movement of the pulley in the direction of the rotation axis; a biasing member that biases each of the pulleys toward the restriction portion; an opposing portion provided on the shaft on the inner side of each of the pulleys with respect to the rotation axis direction; Equipped with A sheet storage device, characterized in that the urging member is located between the pulley and the opposing portion in the rotational axis direction of the shaft, and is in contact with the opposing portion and the pulley.

2. The main body housing has a pair of side walls on which the shaft is rotatably supported, The pulley is disposed outside the pair of side walls, 2. The sheet storage device according to claim 1, wherein the opposing portions are formed by outer surfaces of the pair of side walls.

3. 3. The sheet storage device according to claim 1, wherein each of the pulleys has a tapered shape in which an outer diameter of a winding portion that winds the wire increases toward the outside in the direction of the rotation axis.

4. an image forming apparatus having an image forming unit that forms an image on the sheet; 4. The sheet storage device according to claim 1, further comprising a sheet feeding mechanism connected to the image forming apparatus and feeding the sheets to the image forming unit; An image forming system comprising:

Images