Sheet housing device and image forming apparatus including sheet housing device

Abstract

The invention provides a sheet storage device and an image forming apparatus including the same. The sheet storage device includes: a lift plate; a push-up member; a first gear; the second gear is meshed with the first gear; a transmission mechanism which includes at least a third gear engaged with the second gear and transmits the power of the motor to the push-up member; and a rotation restricting member, the first gear having a support part, the rotation restricting member having: an annular part into which the support part is fitted, the annular part being slidable in the direction of rotation with respect to the outer peripheral surface of the support part; and a protruding portion protruding radially outward from the annular portion and capable of engaging with the second gear, the protruding portion having a shape that cannot pass through a gap between the second gear and the annular portion, and being located further downstream than the gap in a rotation direction of the second gear when rotated by power of the motor.

Description

Technical Field

[0001] The present invention relates to a sheet storage device and an image forming apparatus having the sheet storage device. Background Art

[0002] A conventional sheet storage device includes a lifting plate that can be raised and lowered. The sheets are placed on the lifting plate. The lifting plate is raised to maintain the height of the uppermost sheet on the lifting plate at a predetermined position.

[0003] The conventional sheet storage device has a supply roller that contacts the sheet at a predetermined position from above. The supply roller rotates in contact with the sheet, thereby supplying the sheet. If the uppermost sheet on the lifting plate is not at the predetermined position, the supply roller rotates idle and does not supply the sheet.

[0004] For example, the lifting plate is connected to a gear train including a plurality of gears. The lifting plate is raised by the power of the motor transmitted through the gear train. If the lifting plate is accidentally lowered due to the weight of the lifting plate and the weight of the sheet on the lifting plate, a supply failure such as failure to supply sheets from the sheet storage device may occur. Summary of the invention

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sheet storage device capable of suppressing an unexpected lowering of a lift plate that supports sheets, and an image forming apparatus including the sheet storage device.

[0006] In order to achieve the above-mentioned object, a sheet storage device according to a first aspect of the present invention comprises: a lifting plate, which carries a sheet; a push-up member, which is supported to be rotatable below the lifting plate, and is pushed up by rotating in a lifting direction by the power of a motor transmitted thereto; a first gear, which rotates in one direction by the power of the motor; a second gear, which meshes with the first gear; a transmission mechanism, which at least includes a third gear meshed with the second gear, and transmits the power of the motor to the push-up member; and a rotation limiting member, which limits the push-up member from rotating in a direction opposite to the lifting direction. The first gear has a cylindrical support portion with the central axis of the first gear as a cylindrical axis. The rotation limiting member has an annular portion, in which the support portion is embedded, and which can slide in a direction of rotation relative to the outer peripheral surface of the support portion; and a protrusion, which protrudes from the annular portion in a radially outward direction and can be engaged with the second gear. The protrusion has a shape that cannot pass through the gap between the second gear and the annular portion in a direction orthogonal to the axial direction, and is located on the downstream side of the rotation direction of the second gear when rotating by the power of the motor than the gap.

[0007] An image forming apparatus according to a second aspect of the present invention includes the above-mentioned sheet storage device, conveys sheets and prints images on the sheets.

[0008] According to the structure of the present invention, it is possible to suppress the lift plate that supports the sheet from being accidentally lowered. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram of an image forming apparatus including a sheet storage device according to an embodiment. Figure 2 This is a plan view of a gear train connected to a push-up member of the sheet storage device according to the embodiment, as viewed from the axial direction. Figure 3 It is a perspective view of a first gear and its surroundings in the sheet storage device according to the embodiment. Figure 4 It is a cross-sectional perspective view of a first gear and its surroundings in the sheet storage device according to the embodiment. Figure 5 It is a perspective view of a rotation restricting member of the sheet storage device according to the embodiment. Figure 6 It is a perspective view of a rotation restricting member and its surroundings of the sheet storage device according to the embodiment. Figure 7 It is a diagram showing a state when the switching mechanism of the sheet storage device according to the embodiment transmits the power of the motor. Figure 8 This is a diagram showing a state in which the switching mechanism of the sheet storage device according to the embodiment cuts off the power transmission of the motor. DETAILED DESCRIPTION

[0010] Below, refer to Figures 1 to 8 , a sheet storage device 100 and an image forming apparatus 1000 including the sheet storage device 100 according to an embodiment of the present invention are described. The image forming apparatus 1000 is installed on the ground. The direction perpendicular to the ground (flat surface) on which the image forming apparatus 1000 is installed corresponds to the up-down direction.

[0011] <Structure of Image Forming Apparatus> The image forming apparatus 1000 of this embodiment is a printer. The image forming apparatus 1000 can execute a printing job. The image forming apparatus 1000 prints an image on a sheet S by executing the printing job. The printing method of the image forming apparatus 1000 is, for example, an electrophotographic method. Alternatively, the printing method of the image forming apparatus 1000 may be an inkjet method.

[0012] The image forming apparatus 1000 includes a sheet storage device 100. The sheet storage device 100 stores sheets S used in a printing operation. For example, the sheets S are paper (i.e., made of paper). The image forming apparatus 1000 conveys the sheets S contained in the sheet storage device 100 along a conveying path and prints an image on the sheets S being conveyed. Figure 1 In FIG. 1 , a dotted arrow schematically shows a conveyance path of a sheet S. The direction shown by the arrow is a sheet conveyance direction.

[0013] Hereinafter, the direction perpendicular to the sheet conveying direction and perpendicular to the up-down direction may be referred to as the width direction. Figure 1 In the paper, the direction perpendicular to the paper is the width direction. For example, Figure 1 This corresponds to a diagram in which the image forming apparatus 1000 is viewed from the front. That is, the width direction is also the front-rear direction.

[0014] The image forming apparatus 1000 includes a supply roller 1001. The supply roller 1001 is supported to be rotatable around an axis extending in the width direction. The supply roller 1001 supplies the sheet S stored in the sheet storage device 100 to the conveying path. The supply roller 1001 contacts the sheet S stored in the sheet storage device 100 from above and rotates. Thus, the sheet S is supplied from the sheet storage device 100 to the conveying path.

[0015] The image forming apparatus 1000 includes a pair of registration rollers 1002. The pair of registration rollers 1002 is supported to be rotatable around an axis extending in the width direction. The pair of registration rollers 1002 includes a pair of rollers in pressure contact with each other. The pair of registration rollers 1002 rotates while sandwiching a sheet S sent from a supply roller 1001. Thus, the pair of registration rollers 1002 conveys the sheet S. One of the pair of registration rollers 1002 is a driving roller that rotates by receiving power from a motor M, and the other is a driven roller that rotates following the registration roller on one side.

[0016] The image forming apparatus 1000 includes an image forming unit 1003. The image forming unit 1003 includes a photosensitive drum 1003a and a transfer roller 1003b. The photosensitive drum 1003a and the transfer roller 1003b are supported so as to be rotatable around an axis extending in the width direction. The photosensitive drum 1003a and the transfer roller 1003b are in pressure contact with each other. The photosensitive drum 1003a and the transfer roller 1003b rotate while sandwiching a sheet S sent from the registration roller pair 1002. Thus, the image forming unit 1003 conveys the sheet S.

[0017] Although not shown in the figure, the image forming unit 1003 further includes a charging device, an exposure device, and a developing device. The charging device charges the peripheral surface of the photosensitive drum 1003a. The exposure device forms an electrostatic latent image on the peripheral surface of the photosensitive drum 1003a. The developing device develops the electrostatic latent image on the peripheral surface of the photosensitive drum 1003a into a toner image. The photosensitive drum 1003a transfers the toner image to the sheet S by sandwiching the sheet S between the photosensitive drum 1003a and the transfer roller 1003b and rotating together with the transfer roller 1003b.

[0018] The image forming apparatus 1000 includes a fixing roller pair 1004. The fixing roller pair 1004 is supported so as to be rotatable around an axis extending in the width direction. The fixing roller pair 1004 includes a heating roller and a pressure roller. The heating roller has a built-in heater. The pressure roller is in pressure contact with the heating roller, and the fixing roller pair 1004 rotates while sandwiching the sheet S sent from the image forming unit 1003. That is, the fixing roller pair 1004 heats and presses the sheet S. Thus, the fixing roller pair 1004 fixes the toner image transferred to the sheet S to the sheet S. Then, the sheet S is discharged to the discharge tray ET.

[0019] <Structure of Sheet Storage Device> The sheet storage device 100 includes a sheet cassette CA. The sheet cassette CA stores sheets S. The sheet cassette CA is attachable to and detachable from the apparatus body of the image forming apparatus 1000. When the sheet cassette CA is empty due to execution of a printing job, the sheet cassette CA is pulled out from the apparatus body, the sheets S are stored in the sheet cassette CA, and then the sheet cassette CA is returned to the apparatus body.

[0020] The sheet storage device 100 includes a lifting plate 101. The lifting plate 101 is disposed on the sheet cassette CA. The sheet S is stored in the sheet cassette CA, so that the sheet S is supported on the lifting plate 101. The lifting plate 101 can rotate around an axis extending in the width direction. The lifting plate 101 rotates in such a manner that the end on the downstream side of the sheet feeding direction swings up and down with the end on the upstream side of the sheet feeding direction as a fulcrum. Figure 1 In the figure, the direction from the left side to the right side is the sheet feeding direction.

[0021] During the execution of the printing job, the end portion of the lifting plate 101 on the downstream side in the sheet feeding direction repeatedly rotates in the ascending direction and stops rotating. Thus, the lifting plate 101 maintains the contact between the supply roller 1001 and the uppermost sheet S on the lifting plate 101. Even if the number of sheets S on the lifting plate 101 decreases, the lifting plate 101 rises, thereby maintaining a state in which sheets S can be fed from the sheet cassette CA to the conveying path.

[0022] The sheet storage device 100 includes a push-up component 102. The push-up component 102 is disposed on the sheet box CA. The push-up component 102 is supported below the lifting plate 101 so as to be rotatable around an axis extending in the width direction. The push-up component 102 rotates in such a manner that the end on the downstream side in the sheet feeding direction swings up and down, with the end on the upstream side in the sheet feeding direction as a fulcrum. The push-up component 102 pushes up the lifting plate 101 by rotating in the lifting direction. In addition, the push-up component 102 can also rotate in such a manner that the end on the upstream side in the sheet feeding direction swings up and down, with the end on the downstream side in the sheet feeding direction as a fulcrum. Regardless of the rotation direction of the push-up component 102, the lifting plate 101 can be pushed up by the push-up component 102.

[0023] The sheet storage device 100 receives power from a motor M that rotates the registration roller pair 1002. The push-up member 102 is rotated in the lifting direction by the power of the motor M. However, the present invention is not limited thereto. The push-up member 102 may also be rotated in the lifting direction by the power of a dedicated lifting motor (not shown).

[0024] <Rotation of the push-up member in the lifting direction> The sheet storage device 100 includes a gear train for transmitting the power of the motor M to the rotation shaft 102a of the push-up member 102. Figures 2 to 4 , the gear train of the sheet storage device 100 is described. In addition, all the gears of the sheet storage device 100 are rotatable around an axis extending in the width direction. That is, all the gears of the sheet storage device 100 have the width direction as the axis direction.

[0025] In the following description, the rotation direction of each gear of the sheet storage device 100 is based on the situation viewed from one side in the axial direction. In the following description, the rotation direction of each gear of the sheet storage device 100 is sometimes referred to as one direction and the clockwise direction is sometimes referred to as the other direction.

[0026] The sheet storage device 100 includes a first gear 1 made of resin. Specifically, the sheet storage device 100 includes a cylindrical member 10 made of resin, and the cylindrical member 10 has the first gear 1 integrally. The cylindrical member 10 (i.e., the first gear 1) is supported to be rotatable around the axis of a shaft 10A extending in the width direction. The cylindrical member 10 is a member with a stepped cylindrical shape. The cylindrical member 10 includes a small diameter portion and a large diameter portion whose outer diameter is larger than the outer diameter of the small diameter portion. The first gear 1 is provided on the outer peripheral surface of the small diameter portion in the cylindrical member 10.

[0027] The cylindrical member 10 has a large diameter portion, which is located on one side in the axial direction (i.e., the cylinder axis direction) relative to the small diameter portion provided with the first gear 1. In other words, the first gear 1 has a cylindrical portion (i.e., the large diameter portion) on one side in the axial direction, the outer diameter of which is larger than the outer diameter of the first gear 1. The cylindrical portion on one side in the axial direction of the first gear 1 becomes a support portion 11, which will be described in detail later.

[0028] The first gear 1 is rotated in one direction by the power transmitted by the motor M. When the first gear 1 rotates in one direction, the push-up member 102 rotates in the lifting direction.

[0029] The sheet storage device 100 includes a second gear 2 made of resin. The second gear 2 meshes with the first gear 1. For example, the second gear 2 has a rotation axis below the rotation axis (i.e., the axis 10A) of the first gear 1. The second gear 2 rotates in the other direction by rotating the first gear 1 in one direction after receiving the power of the motor M.

[0030] The second gear 2 is a stepped gear. The second gear 2 is a two-step gear. The second gear 2 has a portion meshing with the first gear 1 as an input side gear 21. The second gear 2 has a portion meshing with the third gear 3 described later as an output side gear 22. A cylindrical boss portion protrudes from the input side gear 21 to one side in the axial direction, and the output side gear 22 is provided on the outer peripheral surface of the boss portion. That is, the outer diameter of the input side gear 21 is larger than the outer diameter of the output side gear 22.

[0031] The sheet storage device 100 includes a transmission mechanism (reference numerals omitted) including a plurality of gears. The transmission mechanism transmits the power of the motor M to the rotation shaft 102a of the push-up member 102, thereby rotating the push-up member 102 in the lifting direction. The transmission mechanism includes at least a resin third gear 3 meshing with the second gear 2. The third gear 3 meshes with the output side gear 22. The third gear 3 rotates in one direction by the second gear 2 rotating in the other direction.

[0032] The transmission mechanism includes a fourth gear 4 and a fifth gear 5, each of which is made of resin. The fourth gear 4 meshes with the third gear 3. The fourth gear 4 rotates in the other direction by the third gear 3 rotating in one direction. The fifth gear 5 meshes with the fourth gear 4. The fifth gear 5 rotates in one direction by the fourth gear 4 rotating in the other direction. In addition, the number of gears constituting the transmission mechanism is not particularly limited.

[0033] The rotation shaft 102a of the push-up member 102 is connected to the fifth gear 5 via a resin gear (not shown). Thus, the power of the motor M is transmitted to the rotation shaft 102a of the push-up member 102. The push-up member 102 rotates in the lifting direction by the power of the motor M, pushing up the lifting plate 101.

[0034] In addition, the sheet storage device 100 includes a switching mechanism 7. The switching mechanism 7 switches between transmission and interruption of power from the motor M to the first gear 1. The first gear 1 rotates in one direction by transmitting power from the motor M to the first gear 1. When the transmission of power from the motor M to the first gear 1 is interrupted, the first gear 1 does not rotate in one direction. If the first gear 1 does not rotate in one direction, the push-up member 102 does not rotate in the lifting direction, and the lifting plate 101 does not rise.

[0035] The structure of the switching mechanism 7 is not particularly limited. It only needs to be able to switch the transmission and disconnection of the power from the motor M to the first gear 1. For example, the switching mechanism 7 includes a planetary gear mechanism. The structure of the switching mechanism 7 is described below. In addition, the structure of the switching mechanism 7 described below is an example. As the switching mechanism 7, a mechanism including an electromagnetic clutch can also be used.

[0036] The switching mechanism 7 has a planetary gear mechanism connected to the first gear 1. Specifically, the switching mechanism 7 has an internal gear 71. The internal gear 71 is supported so as to be rotatable around the axis of the shaft 10A. The internal gear 71 is provided on the inner circumferential surface of the large diameter portion of the cylindrical member 10 having the first gear 1. In other words, the cylindrical member 10 has the internal gear 71 integrally. In addition, since the internal gear 71 and the cylindrical member 10 are the same member, the internal gear 71 is made of resin.

[0037] The switching mechanism 7 includes a resin-made sun gear 72 . The sun gear 72 is supported so as to be rotatable around the axis of the shaft 10A. The sun gear 72 is arranged inside the internal gear 71 (that is, inside the large diameter portion of the cylindrical member 10 ).

[0038] The switching mechanism 7 includes a plurality of planetary gears 73 each made of resin. The plurality of planetary gears 73 are arranged inside the internal gear 71 (that is, inside the large diameter portion of the cylindrical member 10 ) to surround the sun gear 72 . The plurality of planetary gears 73 mesh with the sun gear 72 and mesh with the internal gear 71 .

[0039] The switching mechanism 7 includes a resin planetary carrier 74. The planetary carrier 74 is supported so as to be rotatable around the axis of the shaft 10A. The planetary carrier 74 rotatably supports the plurality of planetary gears 73. Thus, the plurality of planetary gears 73 can revolve around the sun gear 72 while rotating on their own axis. The planetary carrier 74 rotates by causing the plurality of planetary gears 73 to revolve around the sun gear 72.

[0040] The planetary carrier 74 integrally has a power input gear 730. The power input gear 730 can rotate around the axis of the shaft 10A. The power input gear 730 is arranged on one side of the axial direction relative to the cylindrical member 10 (its large diameter portion). The portion of the planetary carrier 74 that supports each planetary gear 73 is arranged on the inner side of the cylindrical member 10, but the portion having the power input gear 730 is arranged on the outer side of the cylindrical member 10. In addition, since the power input gear 730 and the planetary carrier 74 are the same component, the power input gear 730 is made of resin.

[0041] The power input gear 730 and the driving gear 700 (refer to Figure 2 ) is engaged. The driving gear 700 is a gear that is mounted on the rotating shaft of the driving roller in the registration roller pair 1002 and rotates together with the driving roller. That is, the driving gear 700 is a gear located on the most upstream side in the power transmission direction in which the power is transmitted from the motor M to the rotating shaft 102a of the push-up member 102.

[0042] Here, the sun gear 72 integrally includes an engagement rotating body 720 rotatable about the axis of the shaft 10A. The engagement rotating body 720 rotates together with the sun gear 72. Since the sun gear 72 and the engagement rotating body 720 are integral, the sun gear 72 does not rotate when the engagement rotating body 720 is not rotatable.

[0043] The engaging rotating body 720 is arranged on one side in the axial direction relative to the power input gear 730. The engaging rotating body 720 has a boss portion extending to the inner side of the large diameter portion in the cylindrical member 10. The sun gear 72 is provided on the outer peripheral surface of the boss portion extending from the engaging rotating body 720. Thus, the sun gear 72 is arranged on the inner side of the large diameter portion in the cylindrical member 10 and meshes with the plurality of planetary gears 73. In addition, since the engaging rotating body 720 and the sun gear 72 are the same component, the engaging rotating body 720 is made of resin.

[0044] The engaging rotating body 720 has a plurality of protrusions 721 protruding radially outward on the outer peripheral surface. The plurality of protrusions 721 are arranged at intervals in the rotation direction of the engaging rotating body 720. In other words, the engaging rotating body 720 has concavoconvexities on the outer peripheral surface. In other words, the outer peripheral surface of the engaging rotating body 720 can be engaged with the claw member 75 described later.

[0045] During the rotation of the power input gear 730, the engaging rotating body 720 becomes non-rotatable (i.e., the sun gear 72 is non-rotatable), so that the first gear 1 rotates in one direction. That is, the first gear 1 is rotated in one direction by the power transmitted by the motor M. As a result, the second gear 2 rotates in the other direction, and the third gear 3 rotates in one direction, and the push-up member 102 rotates in the lifting direction. As a result, the lifting plate 101 rises.

[0046] During the rotation of the power input gear 730, the engaging rotating body 720 becomes rotatable (i.e., the sun gear 72 is rotatable), so that the power of the motor M is not transmitted to the first gear 1. That is, the transmission of power from the motor M to the first gear 1 is cut off. As a result, the power for rotating the push-up component 102 in the lifting direction is not transmitted to the rotating shaft 102a of the push-up component 102. At this time, the rotation of the first gear 1 is not locked, and the first gear 1 becomes capable of rotating in another direction opposite to one direction.

[0047] In this structure, when the lifting plate 101 is to be raised (i.e., when the push-up component 102 is to be rotated in the lifting direction), the engaging rotating body 720 can be made into a non-rotatable state. When the lifting plate 101 is to be stopped from being raised (i.e., when the push-up component 102 is to be stopped from being rotated in the lifting direction), the engaging rotating body 720 can be made into a rotatable state.

[0048] Therefore, the switching mechanism 7 includes the claw member 75. The claw member 75 has a claw 750 that can engage with the engagement rotating body 720 (the unevenness on the outer peripheral surface thereof). The claw member 75 is supported so as to be rotatable in a direction approaching the engagement rotating body 720 and a direction separating from the engagement rotating body 720.

[0049] The claw member 75 is engaged with the engagement rotating body 720 by rotating in a direction approaching the engagement rotating body 720. The claw 750 is engaged with any one of the plurality of protrusions 721, so that the claw member 75 is engaged with the engagement rotating body 720. The claw member 75 is rotated in a direction away from the engagement rotating body 720, so that the engagement between the engagement rotating body 720 and the claw member 75 is released.

[0050] The switching mechanism 7 includes a solenoid 76. The solenoid 76 includes a movable body 761 and a tension coil spring 762. The movable body 761 is connected to the claw member 75. The claw member 75 approaches the engagement rotating body 720 or separates from the engagement rotating body 720 by the position displacement of the movable body 761. One end of the tension coil spring 762 is connected to the movable body 761.

[0051] The solenoid 76 generates magnetic force to overcome the tension of the tension coil spring 762, displaces the position of the movable body 761, and moves the claw member 75 toward the engagement rotating body 720. That is, the solenoid 76 generates magnetic force to engage the claw member 75 with the engagement rotating body 720.

[0052] On the other hand, when the claw member 75 is moved in the direction of separating from the engagement rotating body 720, the solenoid 76 stops generating the magnetic force. As a result, the claw member 75 is moved in the direction of separating from the engagement rotating body 720 by the tension of the tension coil spring 762. That is, the engagement between the engagement rotating body 720 and the claw member 75 is released.

[0053] The claw member 75 is engaged with the engagement rotating body 720, so that the engagement rotating body 720 cannot rotate, and the sun gear 72 cannot rotate. As a result, the first gear 1 rotates in one direction (that is, the direction to rotate the push-up member 102 in the lifting direction).

[0054] On the other hand, by releasing the engagement between the engagement rotating body 720 and the claw member 75, the engagement rotating body 720 becomes rotatable, and the sun gear 72 becomes rotatable. As a result, the first gear 1 does not rotate in one direction. In other words, the power of the motor M is not transmitted to the first gear 1. At this time, the first gear 1 becomes rotatable in another direction opposite to the one direction.

[0055] <Rotation restriction for restricting the push-up member from rotating in the direction opposite to the lifting direction> The sheet storage device 100 includes Figure 5 and Figure 6 The rotation limiting component 8 shown. The rotation limiting component 8 is made of resin. The rotation limiting component 8 limits the push-up component 102 from rotating in the direction opposite to the lifting direction. The rotation limiting component 8 is supported on the cylindrical component 10. The rotation limiting component 8 limits the push-up component 102 from rotating in the direction opposite to the lifting direction by limiting the rotation of the second gear 2 when the power transmission from the motor M to the first gear 1 is cut off.

[0056] The rotation restricting member 8 has an annular portion 81. When viewed from the axial direction (i.e., the width direction), the annular portion 81 is annular. When viewed from the axial direction, the inner edge of the annular portion 81 is circular. The outer shape of the annular portion 81 when viewed from the axial direction is not particularly limited. For example, when viewed from the axial direction, the annular portion 81 is annular.

[0057] The large diameter portion of the cylindrical member 10 is inserted into the annular portion 81, so that the rotation restricting member 8 is supported by the cylindrical member 10. In this structure, the large diameter portion of the cylindrical member 10 becomes a support portion that supports the rotation restricting member 8. In the following description, the large diameter portion of the cylindrical member 10 is denoted by the reference numeral "11" and is referred to as the support portion 11 (see Figure 3 and Figure 4 ).

[0058] The large diameter portion of the cylindrical member 10 is a part of the first gear 1. That is, the first gear 1 has a cylindrical support portion 11 whose central axis is the cylinder axis. The first gear 1 has the support portion 11 on one side in the axial direction.

[0059] In addition, the rotation limiting member 8 has a protrusion 82 protruding from the annular portion 81 in the radially outward direction. The radially outward direction is a direction from the inside of the annular portion 81 (i.e., the annular body) toward the outside. The protrusion 82 has a plurality of protrusions that can engage with the output side gear 22 in the second gear 2. The second gear 2 has a cylindrical engaging portion with a central axis as a cylindrical axis and having concave and convex shapes on the outer peripheral surface. The output side gear 22 is equivalent to the "engaging portion".

[0060] The rotation restricting member 8 is rotatable around the axis of the first gear 1. Specifically, the annular portion 81 is slidable around the axis of the first gear 1 relative to the outer circumference of the support portion 11. A lubricant such as grease may be disposed between the outer circumference of the support portion 11 and the inner circumference of the annular portion 81.

[0061] The annular portion 81 is arranged at a distance in a direction perpendicular to the axial direction relative to the output side gear 22 (the top end thereof). That is, when viewed from the axial direction, there is a gap G between the output side gear 22 and the annular portion 81. Thus, even if the annular portion 81 slides relative to the outer peripheral surface of the support portion 11 in a rotational manner, the annular portion 81 does not interfere with the output side gear 22.

[0062] However, the protrusion 82 has a shape that cannot pass through the gap G between the output side gear 22 and the annular portion 81 in the direction orthogonal to the axial direction. Therefore, the rotation restricting member 8 rotates around the axis of the first gear 1 by the sliding of the annular portion 81 relative to the outer peripheral surface of the support portion 11, but when the protrusion 82 reaches the gap G, the rotation restricting member 8 stops rotating.

[0063] Here, when viewed from the axial direction, the protrusion 82 is located further downstream in the rotation direction of the output side gear 22 when the output side gear 22 is rotated by the power of the motor M than the gap G between the output side gear 22 and the annular portion 81. Thus, the rotation limiting member 8 functions to limit the rotation of the push-up member 102 in the direction opposite to the lifting direction.

[0064] Below, refer to Figure 7 and Figure 8 Specifically explain. Figure 7 and Figure 8 In FIG. 1 , the rotation direction of the second gear 2 to the fifth gear 5 is indicated by a bold arrow. Figure 7 and Figure 8 The first gear 1 is not shown in the figure.

[0065] When the power of the motor M is transmitted to the rotating shaft 102a of the push-up member 102 to rotate the push-up member 102 in the lifting direction, as shown in FIG. Figure 7 As shown, the claw member 75 is engaged with the engagement rotating body 720. Therefore, the engagement rotating body 720 stops rotating.

[0066] At this time, the first gear 1 rotates in one direction (counterclockwise). The second gear 2 rotates in the other direction (clockwise). The third gear 3 to the fifth gear 5 rotate in the corresponding arrow directions. As a result, the power of the motor M is transmitted to the rotating shaft 102a of the push-up component 102, and the push-up component 102 rotates in the lifting direction. The lifting plate 101 rises.

[0067] On the other hand, when the power transmission from the motor M to the rotating shaft 102a of the push-up member 102 is cut off, as shown in FIG. Figure 8 As shown in FIG. 1 , the engagement between the engagement rotating body 720 and the claw member 75 is released. Therefore, the engagement rotating body 720 can rotate.

[0068] At this time, the first gear 1 stops rotating. When the first gear 1 stops rotating, the second gear 2 also stops rotating. The third gear 3 to the fifth gear 5 also stop rotating. By releasing the engagement between the engagement rotating body 720 and the claw member 75, the first gear 1 becomes rotatable in the other direction.

[0069] Here, when the engagement between the engagement rotating body 720 and the claw member 75 is released, the push-up member 102 tries to rotate in the direction opposite to the lifting direction due to the weight of the lifting plate 101 and the weight of the sheet S on the lifting plate 101. At this time, the second gear 2 to the fifth gear 5 try to rotate in the opposite direction to the lifting direction. Figure 8 The first gear 1 is now able to rotate in the other direction. Therefore, if the second gear 2 tries to rotate in one direction ( Figure 8 The first gear 1 tries to rotate in the other direction.

[0070] If the second gear 2 rotates in one direction, the lifting plate 101 moves downward, and as a result, the supply roller 1001 no longer contacts the sheet S on the lifting plate 101, causing a supply failure of the sheet S from the sheet storage device 100 to the conveying path.

[0071] Therefore, in the present embodiment, a rotation limiting member 8 is disposed on the support portion 11 of the first gear 1. Under this structure, when the second gear 2 rotates in one direction (that is, when the second gear 2 rotates in a direction opposite to the direction of rotation when the second gear 2 rotates using the power of the motor M), the output side gear 22 engages with the protrusion 82 of the rotation limiting member 8, and in this state, the rotation limiting member 8 rotates around the axis of the first gear 1 relative to the outer peripheral surface of the cylindrical member 10. Subsequently, the protrusion 82 reaches the gap G between the output side gear 22 and the annular portion 81, but the protrusion 82 cannot pass through the gap G. That is, the rotation limiting member 8 stops rotating because the protrusion 82 reaches the gap G. At this time, since the output side gear 22 engages with the protrusion 82, the second gear 2 will not rotate further in one direction. If the second gear 2 does not rotate, the third gear 3 to the fifth gear 5 will not rotate either.

[0072] Thus, in this embodiment, the push-up member 102 can be prevented from rotating in the direction opposite to the lifting direction. That is, the lift plate 101 that supports the sheets S can be prevented from accidentally descending. As a result, the supply of the sheets S from the sheet storage device 100 can be prevented from being abnormal.

[0073] In addition, in this embodiment, the rotation restricting member 8 is only composed of Figure 5 The components shown are constructed. Thus, the complexity of the structure can be suppressed. For example, by configuring the worm gear in the gear train, the first gear 1 can be braked by utilizing friction loss. However, if the worm gear is configured in the gear train, the axial direction changes, so the number of parts increases, the structure becomes complicated, and the cost increases. In addition, the driving loss when the push-up component 102 is rotated in the lifting direction becomes larger. On the other hand, by using the rotation limiting component 8, these undesirable situations can be suppressed.

[0074] In addition, in the present embodiment, the rotation limiting member 8 is supported by embedding the support portion 11 into the annular portion 81. Here, the annular portion 81 can slide in the direction of rotation relative to the outer peripheral surface of the support portion 11. Under this structure, when the first gear 1 rotates in one direction using the power of the motor M, the annular portion 81 uses the friction between the outer peripheral surface of the support portion 11 and the force received from the second gear 2 to shift the rotation position in the direction in which the protrusion 82 leaves the gap G. The force received by the annular portion 81 from the second gear 2 is the force of the output side gear 22 to rotate the protrusion 82. Therefore, the rotation of the first gear 1 in one direction is not hindered by the protrusion 82.

[0075] Furthermore, in the present embodiment, the output side gear 22 in the second gear 2 functions as an engaging portion that engages with the protruding portion 82. Thus, there is no need to separately provide an engaging portion that engages with the rotation restricting member 8. In addition, the shape of the engaging portion that engages with the protruding portion 82 is not particularly limited as long as it can engage with the protruding portion 82. That is, the engaging portion may not be a gear.

[0076] It should be understood that the embodiments disclosed this time are illustrative and non-restrictive in all aspects. The scope of the present invention is indicated not by the description of the above embodiments but by the claims, and includes the meaning equivalent to the claims and all changes within the scope of the claims.

Claims

1. A sheet storage device, characterized in that: include: A lifting plate, carrying the sheet body; A push-up component is supported rotatably below the lifting plate, and is rotated in a lifting direction by the power of the motor to push up the lifting plate; A first gear rotates in one direction using the power of the motor; a second gear meshing with the first gear; a transmission mechanism, comprising at least a third gear meshing with the second gear, for transmitting the power of the motor to the push-up member; as well as A rotation limiting component is used to limit the upward push component from rotating in a direction opposite to the lifting direction. The first gear has a cylindrical support portion with the central axis of the first gear as a cylindrical axis. The rotation limiting component has: an annular portion into which the support portion is embedded and which can slide in a rotational direction relative to an outer circumference of the support portion; and a protrusion protruding from the annular portion in a radially outward direction and capable of engaging with the second gear, The protrusion has a shape that cannot pass through a gap between the second gear and the annular portion in a direction perpendicular to the axial direction, and is located downstream of the gap in the rotation direction of the second gear when the second gear rotates by power of the motor.

2. The sheet storage device according to claim 1, wherein: A switching mechanism is included, wherein the switching mechanism switches the transmission and cutoff of power from the motor to the first gear, When the transmission of power from the motor is cut off, the first gear is in a state of being rotatable in another direction opposite to the one direction.

3. The sheet storage device according to claim 2, wherein: By cutting off the transmission of power from the motor to the first gear, when the second gear rotates in a direction opposite to the direction of rotation when rotating using the power of the motor, the rotation limiting component rotates with the protrusion engaged with the second gear. If the protrusion reaches the gap, the rotation limiting component stops rotating.

4. The sheet storage device according to any one of claims 1 to 3, characterized in that: When the first gear rotates in the one direction, the annular portion shifts its rotational position in a direction in which the protrusion leaves the gap by a friction force between the annular portion and the outer peripheral surface of the support portion and a force received from the second gear.

5. The sheet storage device according to any one of claims 1 to 3, characterized in that: The second gear is a stepped gear having: An input side gear meshing with the first gear; as well as The output side gear meshes with the third gear, The protrusion is engageable with the output-side gear.

6. An image forming device, characterized in that: A sheet storage device comprising the sheet storage device according to any one of claims 1 to 5, The sheet is conveyed and an image is printed on the sheet.

Images