DOCUMENT CONVEYING DEVICE

Abstract

A document conveying device includes a sheet feeding tray, a sheet feeding mechanism, a sheet feeding tray lifting mechanism, a top plate, a fixed wall part, and a lifting wall part. The top plate is in contact with a lower surface of the document to be fed. The fixed wall part is provided extending downward from an upstream side end portion of the top plate, and fixed in position. The lifting wall part is provided extending upward from a downstream side end portion of the sheet feeding tray, and is lifted and lowered along the fixed wall part together with the sheet feeding tray. The lifting wall part has a slit along an upper-and-lower direction. The fixed wall part has a fin along the upper-and-lower direction. An upper end portion of the slit is opened in the upper-and-lower direction. The fin is arranged inside the slit.

Claims

1. A document conveying device comprising: a sheet feeding tray on which a document is placed; a sheet feeding mechanism which feeds the document placed on the sheet feeding tray in a predetermined sheet feeding direction; a sheet feeding tray lifting mechanism which lifts and lowers the sheet feeding tray; a top plate which is adjacent to the sheet feeding tray on a downstream side in the sheet feeding direction and is in contact with a lower surface of the document to be fed; a fixed wall part which is provided extending downward from an upstream side end portion of the top plate in the sheet feeding direction, and fixed in position; and a lifting wall part which is provided extending upward from a downstream side end portion of the sheet feeding tray in the sheet feeding direction, faces the fixed wall part on an upstream side of the fixed wall part in the sheet feeding direction, and is lifted and lowered along the fixed wall part together with the sheet feeding tray, wherein the lifting wall part has a slit along an upper-and-lower direction, the fixed wall part has a fin along the upper-and-lower direction, an upper end portion of the slit is opened in the upper-and-lower direction, and the fin protrudes upstream of the sheet conveying direction, and is arranged inside the slit.

2. The document conveying device according to claim 1, wherein the slit is provided at a plurality of positions in a width direction crossing the sheet feeding direction, the fin is provided at a plurality of positions corresponding to the slits, and at least two of the fins are in contact with the document placed on the sheet feeding tray.

3. The document conveying device according to claim 1, wherein edge portions of the slit protrude upstream of the sheet feeding direction, and a tip of the fin and tips of the edge portions of the slit on both sides of the fin form a same plane.

4. The document conveying device according to claim 1, wherein an upper end portion of the fin is inclined such that a downstream side portion in the sheet feeding direction is high.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a front view schematically showing an internal structure of an image forming apparatus according to a first embodiment of the present disclosure.

[0009] FIG. 2 is a perspective view showing an external appearance of a document conveying device according to the first embodiment of the present disclosure.

[0010] FIG. 3 is a front view schematically showing a sheet feeding mechanism and a conveying mechanism according to the first embodiment of the present disclosure.

[0011] FIG. 4 is a front view schematically showing the conveying mechanism and a sheet feeding tray lifting mechanism according to the first embodiment of the present disclosure.

[0012] FIG. 5 is a rear view schematically showing the sheet feeding tray lifting mechanism according to the first embodiment of the present disclosure.

[0013] FIG. 6 is a front view schematically showing the conveying mechanism and the sheet feeding tray lifting mechanism according to the first embodiment of the present disclosure.

[0014] FIG. 7 is a perspective view showing a fixed wall part, a lifting wall part, and a sheet feeding tray according to the first embodiment of the present disclosure.

[0015] FIG. 8 is a perspective view showing the fixed wall part, the lifting wall part, and the sheet feeding tray according to the first embodiment of the present disclosure.

[0016] FIG. 9 is a perspective view showing the fixed wall part, the lifting wall part, and the sheet feeding tray according to the first embodiment of the present disclosure.

[0017] FIG. 10 is a disassembled view showing the fixed wall part and the lifting wall part according to the first embodiment of the present disclosure.

[0018] FIG. 11 is a disassembled view showing the fixed wall part and the lifting wall part according to the first embodiment of the present disclosure.

[0019] FIG. 12 is a perspective view showing a cross section of the lifting wall part and the front portion of the sheet feeding tray according to the first embodiment of the present disclosure.

[0020] FIG. 13 is a disassembled view showing the fixed wall part and the lifting wall part according to a second embodiment of the present disclosure.

[0021] FIG. 14 is a perspective view showing a state where the lifting wall part according to the second embodiment of the present disclosure is positioned at a lower limit position.

[0022] FIG. 15 is a perspective view showing a state where the lifting wall part according to the second embodiment of the present disclosure is positioned at an upper limit position.

[0023] FIG. 16 is a view showing the fixed wall part, the lifting wall part, and the sheet feeding tray according to the first embodiment of the present disclosure, as viewed from a right and upper oblique direction.

[0024] FIG. 17 is a view showing the fixed wall part, the lifting wall part, and the sheet feeding tray according to the second embodiment of the present disclosure, as viewed from a right and upper oblique direction.

BRIEF DESCRIPTION OF THE DISCLOSURE

First Embodiment

[0025] Hereinafter, with reference to the drawings, a document conveying device 120 and an image forming apparatus 100 according to one embodiment of the present disclosure will be described.

[0026] First, the overall configuration of the image forming apparatus 100 will be described. FIG. 1 is a front view schematically showing the internal structure of the image forming apparatus 100. Hereinafter, the front side of the paper plan on which FIG. 1 is drawn is defined as the front side of the image forming apparatus 100, and the right-and-left directions will be described with reference to the direction in which the image forming apparatus is viewed from the front side. In each figure, U, Lo, L, R, Fr, and Rr indicate the upper, lower, left, right, front, and rear, respectively.

[0027] The image forming apparatus 100 includes a recording device 1, an image reading device 110, and a document conveying device 120. The image reading device 110 is provided above the recording device 1, and the document conveying device 120 is provided above the image reading device 110. The document conveying device 120 conveys a document G via a reading position A of the image reading device 110. The image reading device 110 is a flatbed type image reading device, and reads the document G to generate image data. The recording device 1 forms an image on a sheet S based on the image data. In this embodiment, the recording device 1 forms the image in an electrophotographic system, but the recording device 1 may be configured to form an image in another system (for example, an inkjet system).

[0028] The recording device 1 includes a rectangular parallelepiped body housing 3. In the lower portion in the body housing 3, a sheet feeding cassette 4 in which the sheet S is housed and a sheet feeding roller 5 which feeds the sheet S rightward from the sheet feeding cassette 4 are provided. Above the sheet feeding cassette 4, an image forming device 6 which forms a toner image in an electrophotographic manner is provided, and a fixing device 7 which fixes the toner image to the sheet S is provided in the right and upper side of the image forming device 6. Above the fixing device, a discharge roller 8 which discharges the sheet S to which the toner image is fixed and a discharge tray 9 on which the discharged sheet S is stacked are provided.

[0029] Inside the body housing 3, a conveyance path 10 from the sheet feeding roller 5 through the image forming device 6 and the fixing device 7 to the discharge roller 8 is provided. The conveyance path 10 is formed mainly of plate-like members facing each other with a gap for passing the sheet S, and a conveyance roller 17 for holding and conveying the sheet S is provided at a plurality of positions in the conveyance direction Y. A registration roller 18 is provided on the upstream side of the image forming device 6 in the conveyance direction Y. On the right side of the fixing device 7, there is provided an inversion conveyance path 10R which branches from the conveyance path 10 on the downstream side of the fixing device 7 in the conveyance direction Y and merges with the conveyance path 10 on the upstream side of the registration roller 18 in the conveyance direction Y.

[0030] A control part 2 includes an arithmetic part and a storage part (not shown). The arithmetic part is, for example, a CPU (Central Processing Unit). The storage part includes a storage medium such as ROM (Read Only Memory), RAM (Random Access Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The arithmetic part reads and executes control program stored in the storage part to perform various processes. The control part 2 may be implemented only by an integrated circuit without using software.

[0031] A display operation part (not shown) is provided on the front side of the image reading device 110. The display operation part is provided with a display panel, a touch panel superposed on the display surface of the display panel, and a keypad adjacent to the display panel (not shown). The control part 2 displays a screen showing an operation menu and a status of the recording device 1 and the image reading device 110 on the display panel, and controls each part of the recording device 1 and the image reading device 110 according to an operation detected by the touch panel and the keypad.

[0032] The basic image forming operation of the recording device 1 is as follows. When a single-sided printing job is input to the recording device 1 from the display operation part or an external computer, the sheet feeding roller 5 feeds the sheet S from the sheet feeding cassette 4 to the conveyance path 10, the registration roller 18 whose rotation is stopped corrects the skew of the sheet S, and the registration roller 18 feeds the sheet S to the image forming device 6 at a predetermined timing. The image forming device 6 forms a toner image on the sheet S by the electrophotographic method. Subsequently, the fixing device 7 fixes the toner image to the sheet S by melting the toner image while holding and conveying the sheet S, and the discharge roller 8 discharges the sheet S to the discharge tray 9. In the case of double-sided printing, the sheet S on which the toner image is fixed on the first surface is fed to the conveyance path 10 via the inversion conveyance path 10R, whereby the toner image is transferred to the second surface.

[0033] [Image Reading Device] The image reading device 110 includes a first carriage 81 including a light source and a reflecting mirror, a second carriage 82 including two reflecting mirrors, a lens 83 for forming an image with light, an imaging element 84 for converting the formed light into image data, and a contact glass 85 on which the document G is placed.

[0034] The basic document reading operation of the image reading device 110 is as follows. When the user places the document G on the upper surface of the contact glass 85 and gives a reading instruction to the image reading device 110, the first carriage 81 moves rightward at a speed V while the second carriage 82 moves rightward at a speed V/2. During this time, the light source irradiates the document G with light, and the reflected light reflected by the document G is reflected by the reflecting mirror of the first carriage 81 and the reflecting mirrors of the second carriage 82, is guided to the lens 83, forms an image on the imaging element 84, and is converted into an image signal. The image signal is output to the control part 2 of the recording device 1 and converted into the image data.

[0035] [Document Conveying Device] Next, the document conveying device 120 will be described. FIG. 2 is a perspective view showing an external appearance of the document conveying device 120. FIG. 3 is a front view schematically showing a sheet feeding mechanism 31 and a conveying mechanism 32. FIG. 4 and FIG. 6 are front views schematically showing the conveying mechanism 32 and a sheet feeding tray lifting mechanism 33. FIG. 5 is a rear view schematically showing the sheet feeding tray lifting mechanism 33. FIG. 3, FIG. 4, and FIG. 5 show a state in which a sheet feeding tray 44 is positioned near the upper limit position, and FIG. 6 shows a state in which the sheet feeding tray 44 is positioned near the lower limit position.

[0036] The document conveying device 120 (see FIG. 2 and FIG. 3) includes a generally rectangular bottom portion 40 formed in a flat shape, and a first wall portion 41 and a second wall portion 42 facing each other in the front-and-rear direction (the width direction intersecting the sheet feeding direction Z of the document G). The rear edge portion of the bottom portion 40 is hinged on the rear side of the contact glass 85 (see FIG. 1) of the image reading device 110. The bottom portion 40 also has a function of holding the document G on the contact glass 85. The first wall portion 41 is provided from the left end portion to the center portion of the front edge portion of the bottom portion 40. The second wall portion 42 is provided over the entire area of the rear edge portion of the bottom portion 40. A cover portion 46 covers the upper and left sides of the space between the first wall portion 41 and the second wall portion 42. The left lower end portion of the cover portion 46 is hinged to the left end portion of the bottom portion 40.

[0037] [Sheet Feeding Tray] A sheet feeding tray 44 (see FIG. 2 and FIG. 3) is provided on the right side of the center of the document conveying device 120 in the left-and-right direction and on the front side of the second wall portion 42. The sheet feeding tray 44 is a plate-like member inclined such that the left side is lowered. On the upper surface of the sheet feeding tray 44, a pair of cursors 45 for aligning the front and rear ends of the document G are provided. The cursor 45 is slidable in the front-and-rear direction.

[0038] [Discharge Tray] A discharge tray 43 is provided below the sheet feeding tray 44. The discharge tray 43 is integral with the bottom portion 40.

[0039] [Sheet Feeding Mechanism] A sheet feeding mechanism 31 (see FIG. 3) is provided in the space between the first wall portion 41 and the second wall portion 42. The sheet feeding mechanism 31 is provided with a box-shaped holder 53 whose lower portion is opened. Inside the holder 53, a pickup roller 51, a driven roller 55, a driving roller 52, and a retard roller 57 are arranged with their axial directions along the front-and-rear direction. The driven roller 55 is provided on the left side of the pickup roller 51. The driving roller 52 is provided on the left side of the driven roller 55. An endless belt 56 is wound around the driving roller 52 and the driven roller 55. The retard roller 57 is pressed against the lower surface of the lower portion of the endless belt 56.

[0040] Both front and rear ends of a driving shaft 54 of the driving roller 52 are supported by the first wall portion 41 and the second wall portion 42, and are connected to a drive part (not shown) including a motor and a reduction gear. The holder 53 is supported by the driving shaft 54, and can be turned around the driving shaft 54. A driving force is transmitted from the driving shaft 54 to the pickup roller 51 and the retard roller 57 by a transmission mechanism (not shown) such as a gear train or an endless belt.

[0041] A sensor 58 is a transmission type or a reflection type optical sensor, and is provided on the inner surface of the cover portion 46. A light shielding plate 59 protruding upward or sideways is provided on the upper portion of the holder 53. The sensor 58 outputs detection signals having different level to the control part 2 when the light shielding plate 59 blocks the light of the sensor 58 and when the light shielding plate does not block the light.

[0042] [Sheet Feeding Tray Lifting Mechanism] A sheet feeding tray lifting mechanism 33 (see FIG. 4 and FIG. 5) is provided on the front surface of the first wall portion 41 and the rear surface of the second wall portion 42. A driving pulley 71 and a driven pulley 72 (see FIG. 5) are provided at the upper and lower portions of the central portion of the rear surface of the second wall portion 42, respectively. A driven pulley 73 is provided at an intermediate height between the driving pulley 71 and the driven pulley 72 and on the left side of the driving pulley 71 and the driven pulley 73. A guide pulley 76 is provided on the left upper side of the driven pulley 72 and on the right side of the driven pulley 73. An endless belt 70 is wound around the driving pulley 71, the driven pulleys 72 and 73, and the guide pulley 76. A driving part 78 includes a motor 78M, a worm gear 78W, an idler gear 78i, and a driving gear 71G. The driving gear 71G is provided on the shaft of the driving pulley 71.

[0043] Driven pulleys 91, 92, 93, and the guide pulley 96 (see FIG. 4) are provided on the front surface of the first wall portion 41 at positions facing the driving pulley 71, the driven pulleys 72, 73, and the guide pulley 76, respectively. An endless belt 90 is wound around the driven pulleys 91, 92, 93 and the guide pulley 96. The driven pulley 93 is provided on the common shaft with the driven pulley 73.

[0044] A sliding part 74 (see FIG. 5) is provided at the left end portion of the rear edge portion of the sheet feeding tray 44. The second wall portion 42 is provided with a slit 42S whose longitudinal direction is along the upper-and-lower direction. The slit 42S is provided at a position corresponding to the left end portion of the rear edge portion of the sheet feeding tray 44. The sliding part 74 penetrates the slit 42S, and is coupled to the endless belt 70 between the driving pulley 71 and the driven pulley 72.

[0045] A lifting guide part 75 is provided on the rear surface of the second wall portion 42. The lifting guide part 75 is a rail-like member whose longitudinal direction is along the upper-and-lower direction. The sliding part 74 is slidable in the upper-and-lower direction along the lifting guide part 75.

[0046] A sliding part 94 (see FIG. 4) is provided at the left end portion of the front edge portion of the sheet feeding tray 44. The sliding part 94 is coupled to the endless belt 90 between the driven pulley 91 and the driven pulley 92.

[0047] A lifting guide part 95 is provided on the front surface of the first wall portion 41. The lifting guide part 95 is a rail-like member whose longitudinal direction is along the upper-and-lower direction. The sliding part 94 is slidable in the upper-and-lower direction along the lifting guide part 95.

[0048] The basic operation of the sheet feeding tray lifting mechanism 33 is as follows. A driving force generated by the motor 78M is transmitted to the driving gear 71G via the worm gear 78W and the idler gear 78i. The driving pulley 71 is rotated together the driving gear 71G, the endless belt 70 travels, and the driven pulleys 72 and 73 are rotated accordingly. The driven pulley 93 is rotated together with the driven pulley 73, and the endless belt 90 travels synchronously with the endless belt 70. Since the sheet feeding tray 44 is coupled to the endless belts 70, 90 via the sliding parts 74, 94, the sheet feeding tray 44 is lifted and lowered by the forward and reverse rotations of the motor 78M.

[0049] The control part 2 controls the sheet feeding tray lifting mechanism 33 to lift the sheet feeding tray 44. When the upper surface of the document G placed on the sheet feeding tray 44 is pressed against the pickup roller 51, the holder 53 is turned upward. When the holder 53 is turned upward by a predetermined amount, the light shielding plate 59 blocks the light of the sensor 58. At this time, an appropriate load acts between the upper surface of the document G and the pickup roller 51, and the document G can be fed by the pickup roller 51. In other words, the control part 2 controls the sheet feeding tray lifting mechanism 33 so as to lift the sheet feeding tray 44 as an amount of documents G placed on the sheet feeding tray 44 decreases.

[0050] [Conveying Mechanism] A conveying mechanism 32 (see FIG. 3) includes a conveyance path 61 extending from the sheet feeding mechanism 31 to the discharge roller 69 via an opening 40A, and a plurality of conveying rollers 62 arranged in the conveyance path 61. The conveyance path 61 is formed mainly of plate-like members facing each other with a gap through which the document G can pass. The opening 40A is a slit provided in the bottom portion 40 at a region facing the first carriage 81 (see FIG. 1) located at the home position and whose longitudinal direction is along the front-and-rear direction. The opening 40A is an example of the reading position A where the image reading device 110 reads the document G. At the reading position A, an opening 61A corresponding to the opening 40A is provided in a plate-like member on the lower side of the conveyance path 61, and the lower surface of the document G being conveyed is exposed downward through the openings 40A and 61A.

[0051] The conveying roller 62 includes a driving roller 62D and a driven roller 62N (see FIG. 3). A driven pulley 63N (see FIG. 4) is provided on the shaft of the driving roller 62D. A driving pulley 63D is connected to a driving part (not shown) including a motor and a reduction gear. An endless belt 60 is wound around the driving pulley 63D, the driven pulleys 63N, and a guide pulley 63G. When the driving pulley 63D is driven, the endless belt 60 is traveled and the driven pulleys 63N are rotated synchronously, so that the conveying rollers 62 are also rotated synchronously.

[0052] A guide part 64 (FIG. 3) is provided in the conveyance path 61 on the downstream side of the opening 40A in the sheet feeding direction Z. The guide part 64 is formed by integrating plate-like members facing in the upper-and-lower direction, and is turned around the driving roller 62D or the driven roller 62N of the conveying roller 62 adjacent to the right side of the opening 40A. A description of the mechanism for turning the guide part 64 is omitted.

[0053] [Structure of Fixed Wall Part and Lifting Wall Part] Next, a fixed wall part 23 and a lifting wall part 25 will be described. FIG. 7 to FIG. 9 are perspective views showing the fixed wall part 23, the lifting wall part 25, and the sheet feeding tray 44. FIG. 7 shows a state where the lifting wall part 25 and the sheet feeding tray 44 are positioned at the lower limit position. FIG. 8 shows a state in which the lifting wall part 25 is positioned at the upper limit position and the sheet feeding tray 44 is positioned at the intermediate position. FIG. 9 shows a state in which the lifting wall part 25 is positioned at the upper limit position and the sheet feeding tray 44 is positioned at the upper limit position. FIG. 10 and FIG. 11 are disassembled views showing the fixed wall part 23 and the lifting wall part 25.

[0054] The document conveying device 120 includes the sheet feeding tray 44 on which the document G is placed, the sheet feeding mechanism 31 which feeds the document G placed on the sheet feeding tray 44 in the predetermined sheet feeding direction Z, the sheet feeding tray lifting mechanism 33 which lifts and lowers the sheet feeding tray 44, a top plate 22 adjacent to the sheet feeding tray 44 on the downstream side in the sheet feeding direction Z and in contact with the lower surface of the document G to be fed, the fixed wall part 23 provided extending downward from the upstream end portion of the top plate 22 in the sheet feeding direction Z and fixed in position, and the lifting wall part 25 provided extending upward from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z and lifting/lowering along the fixed wall part 23 together with the sheet feeding tray 44.

[0055] [Top Plate] The top plate 22 (see FIG. 7 to FIG. 11) is provided generally horizontally. An opening 21A is provided at the center of the top plate 22 in the front-and-rear direction. The retard roller 57 included in the sheet feeding mechanism 31 is disposed in the opening 21A. The document G fed by the pickup roller 51 is conveyed along the upper surface while bringing its lower surface into contact with the upper surface of the top plate 22.

[0056] [Fixed Wall Part] The fixed wall part 23 is a rectangular member whose longitudinal direction is along the front-and-rear direction as a whole, and is provided in a posture downwardly upright from the upstream end portion of the top plate 22 in the sheet feeding direction Z, and is integrated with the top plate 22. The fixed wall part 23 includes a plurality of convex portions 23T1, 23T2, 23T3, 23T4, 23T5, 23T6, and 23T7, and a plurality of concave portions 23U1, 23U2, 23U3, 23U4, 23U5, and 23U6. The convex portions 23T1 to 23T7 are provided at intervals along the upstream end portion of the top plate 22 in the sheet feeding direction Z, protrude toward the sheet feeding tray 44, and have a hollow structure with the lower end portion opened. The concave portions 23U1 to 23U6 are alternately provided with the convex portions 23T1 to 23T7. The convex portion 23T1, the concave portion 23U1, the convex portion 23T2, the concave portion 23U2, the convex portion 23T3, the concave portion 23U3, the convex portion 23T4, the concave portion 23U4, the convex portion 23T5, the concave portion 23U5, the convex portion 23T6, the concave portion 23U6, and the convex portion 23T7 are arranged in this order from the front side.

[0057] Each of the convex portions 23T1 to 23T7 is formed in a substantially rectangular parallelepiped shape having a smaller dimension in the left-and-right direction than the upper-and-lower direction. The upper end portions of the convex portions 23T1 to 23T7 and the concave portions 23U1 to 23U6 are inclined so that the downstream side in the sheet feeding direction Z becomes higher. Shapes and dimensions of the convex portions 23T1 to 23T7 may be different from each other as shown, but may be the same. Shapes and dimensions of the concave portions 23U1 to 23U6 may be different from each other as shown, but may be the same.

[0058] [Restriction Part] Side wall parts 23W are provided extending downwardly upright from both front and rear end portions of the top plate 22. The side wall parts 23W are integrated with the top plate 22 and the fixed wall part 23. A restriction part 23R is a slit provided in the side wall part 23W along the upper-and-lower direction. The upper end of the restriction part 23R is closed, and the lower end is opened.

[0059] [Lifting Wall part] A bottom plate 24 faces the top plate 22 below the top plate 22. The lifting wall part 25 is provided extending upwardly upright from the upstream end portion of the bottom plate 24 in the sheet feeding direction Z, and is integrated with the bottom plate 24. The lifting wall part 25 includes a plurality of convex fitting portions 25T1, 25T2, 25T3, 25T4, 25T5, 25T6, and 25T7, and a plurality of concave fitting portions 25U1, 25U2, 25U3, 25U4, 25U5, and 25U6. The convex fitting portions 25T1, 25T2, 25T3, 25T4, 25T5, 25T6, and 25T7 are fitted inside the convex portions 23T1, 23T2, 23T3, 23T4, 23T5, 23T6, and 23T7, respectively. The concave fitting portions 25U1, 25U2, 25U3, 25U4, 25U5, and 25U6 are fitted inside the concave portions 23U1, 23U2, 23U3, 23U4, 23U5, and 23U6, respectively. With the lifting and lowering of the sheet feeding tray 44, the convex fitting portions 25T1 to 25T7 slide along the convex portions 23T1 to 23T7, and the concave fitting portions 25U1 to 25U6 slide along the concave portions 23U1 to 23U6.

[0060] [End Portion] The front and rear end portions 25E of the lifting wall part 25 are inserted into the restriction parts 23R, and slide along the restriction parts 23R. Since the upper end portion of the restriction part 23R is closed, when the end portion 25E comes into contact with the upper end portion of the restriction part 23R, the lifting of the lifting wall part 25 is stopped. When the end portion 25E comes into contact with the upper end portion of the restriction part 23R, the upper end portion of the lifting wall part 25 becomes the same height as the upper end portion of the fixed wall part 23. Protrusions 25B protrude in the front-and-rear direction from the front and rear end portions 25E of the lifting wall part 25.

[0061] [Biasing Member] A biasing member 26 (see FIG. 10 and FIG. 11) is a tension coil spring disposed between the top plate 22 and the bottom plate 24 in an upright posture. The upper end of the biasing member 26 is attached to the lower surface of the top plate 22, and the lower end is attached to the upper surface of the bottom plate 24. Since the top plate 22 is fixed, the bottom plate 24 and the lifting wall part 25 are biased upward.

[0062] [Engagement Part] FIG. 12 is a perspective view showing the front portions of the fixed wall part 23, the lifting wall part 25, the sheet feeding tray 44, and the discharge tray 43. FIG. 13 is a perspective view showing a cross section of the front portions of the lifting wall part 25, the sheet feeding tray 44, and the discharge tray 43. FIG. 14 is a perspective view showing the discharge tray 43. FIG. 15 is a perspective view showing an engagement part 44R. FIG. 16 is a perspective view showing a cross section of the engagement part 44R.

[0063] Since the lifting wall part 25 is biased upward by the biasing member 26 as described above, the protrusion 25B is pressed against the recess portion 44G. With this configuration, the lifting of the lifting wall part 25 is restricted, and the lifting wall part 25 is kept in a state of protruding upward by a predetermined height from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z.

[0064] Next, the operation of this embodiment will be described. When the lifting wall part 25 is positioned at the lower limit position (see FIG. 7), the upper end portion of the lifting wall part 25 is positioned slightly above the lower end portion of the fixed wall part 23, so that a gap in the upper-and-lower direction does not occur between the lifting wall part 25 and the fixed wall part 23. In this case, a height of the wall formed by the lifting wall part 25 and the fixed wall part 23 becomes maximum, and a capacity of the sheet feeding tray 44 (an amount of the document G that can be placed) becomes maximum.

[0065] Since the lifting wall part 25 is biased upward by the biasing member 26, when the sheet feeding tray 44 is lifted by the sheet feeding tray lifting mechanism 33, the lifting wall part 25 is also lifted together with the sheet feeding tray 44. At this time, the convex fitting portions 25T1 to 25T7 of the lifting wall part 25 slide along the convex portions 23T1 to 23T7 of the fixed wall part 23, and the concave fitting portions 25U1 to 25U6 of the lifting wall part 25 slide along the concave portions 23U1 to 23U6 of the fixed wall part 23.

[0066] When the front and rear end portions 25E of the lifting wall part 25 are in contact with the upper end portions of the restriction parts 23R (see FIG. 8), the lifting of the lifting wall part 25 is stopped, and the lifting wall part 25 reaches the upper limit position. At this time, the sheet feeding tray 44 is positioned at the intermediate position between the lower limit position and the upper limit position. When the sheet feeding tray 44 is lifted further, the recess portions 44G of the engagement part 44R are separated from the protrusions 25B of the lifting wall part 25, and only the sheet feeding tray 44 is lifted.

[0067] When the sheet feeding tray 44 reaches the upper limit position (see FIG. 9), the downstream end portion of the upper surface of the sheet feeding tray 44 in the sheet feeding direction Z is positioned slightly below the upper surface of the top plate 22. In this case, a height of the wall formed by the lifting wall part 25 and the fixed wall part 23 becomes minimum, and a capacity of the sheet feeding tray 44 becomes minimum. As described above, since the upper end portions of the convex portions 23T1 to 23T7 and the concave portions 23U1 to 23U6 of the fixed wall part 23 are inclined so that the downstream side in the sheet feeding direction Z becomes higher, the document G is smoothly fed from the sheet feeding tray 44 toward the top plate 22.

[0068] When the sheet feeding tray 44 is moved downward from the upper limit position and reaches the intermediate position (see FIG. 8), the recess portion 44G of the engagement part 44R comes into contact with the protrusion 25B of the lifting wall part 25. When the sheet feeding tray 44 is further lowered, the protrusion 25B is pushed down by the recess portion 44G, and the lifting wall part 25 is lowered together with the sheet feeding tray 44.

[0069] The document conveying device 120 according to the present embodiment described above includes the sheet feeding tray 44 on which the documents G are placed; the sheet feeding mechanism 31 which feeds the document G placed on the sheet feeding tray 44 in the predetermined sheet feeding direction Z; the sheet feeding tray lifting mechanism 33 which lifts and lowers the sheet feeding tray 44; the top plate 22 adjacent to the sheet feeding tray 44 on the downstream side in the sheet feeding direction Z and in contact with the lower surface of the documents G to be fed; the fixed wall part 23 which is provided extending downward from the upstream end portion of the top plate 22 in the sheet feeding direction Z and fixed in position; and the lifting wall part 25 which is provided extending upward from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z, and lifted and lowered along the fixed wall part 23 together with the sheet feeding tray 44. According to this configuration, the downstream edge of the document G in the sheet feeding direction Z is positioned by the wall formed by the fixed wall part 23 and the lifting wall part 25. As the sheet feeding tray 44 is lowered, a height of the wall increases, thereby increasing a capacity of the sheet feeding tray 44. Accordingly, according to the present embodiment, a capacity of the sheet feeding tray 44 can be increased without increasing a size of the downstream wall of the sheet feeding tray 44 in the sheet feeding direction Z in the upper-and-lower direction. As a result, since a height of the discharge port for discharging the document G to the discharge tray 43 can be varied in a wide range, a capacity of the discharge tray 43 can be increased.

[0070] According to the document conveying device 120 according to the present embodiment, the fixed wall part 23 includes the convex portions 23T1 to 23T7 provided at intervals along the upstream end portion of the top plate 22 in the sheet feeding direction Z, protruding to the sheet feeding tray 44 and having a hollow structure with the lower end portion opened, and the concave portions 23U1 to 23U6 provided alternately with the convex portions 23T1 to 23T7, and the lifting wall part 25 includes the convex fitting portions 25T1 to 25T7 fitted inside the convex portions 23T1 to 23T7, and the concave fitting portions 25U1 to 25U6 fitted inside the concave portions 23U1 to 23U6. According to this configuration, since the convex fitting portions 25T1 to 25T7 slide with respect to the convex portions 23T1 to 23T7 and the concave fitting portions 25U1 to 25U6 slide with respect to the concave portions 23U1 to 23U6, the lifting wall part 25 can be lifted and lowered smoothly and in a stable posture.

[0071] Further, according to the document conveying device 120 according to the present embodiment, the biasing member 26 is provided for biasing the lifting wall part 25 upward, and the sheet feeding tray 44 is provided with the engagement part 44R for restricting the lifting of the lifting wall part 25. According to this configuration, it is possible to keep the lifting wall part 25 in a posture protruding upward by a predetermined height from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z.

[0072] According to the document conveying device 120 according to the present embodiment, the fixed wall part 23 includes the restriction part 23R for restricting the lifting of the lifting wall part 25 so that a height of the upper end portion of the lifting wall part 25 does not exceed a height of the upper end portion of the fixed wall part 23. According to this configuration, it is possible to prevent the lifting wall part 25 from obstructing the conveying of the document G.

[0073] According to the document conveying device 120 according to the present embodiment, the sheet feeding tray 44 can be lifted to a predetermined height above the position of the sheet feeding tray 44 when the lifting wall part 25 reaches the upper limit position. According to this configuration, even if an amount of the document G placed on the sheet feeding tray 44 is small, it becomes possible to feed the document G.

Second Embodiment

[0074] Next, the document conveying device 120 according to a second embodiment of the present disclosure will be described in comparison with the first embodiment. FIG. 16 is a view of the fixed wall part 23, the lifting wall part 25, and the sheet feeding tray 44 according to the first embodiment, as viewed from the right and upper oblique direction. It shows a state in which the lifting wall part 25 and the sheet feeding tray 44 are positioned at the lower limit position (see FIG. 7). Since the fixed wall part 23, the lifting wall part 25, and the sheet feeding tray 44 are generally formed symmetrically with respect to the front-and-rear direction, as shown in FIG. 16, a portion on the front side of the center portion in the front-and-rear direction will be described.

[0075] In the first embodiment, as described above, the convex fitting portions 25T1, 25T2, and 25T3 are fitted inside the convex portions 23T1, 23T2, and 23T3, respectively. For this reason, gaps A1, A2 and A3 (see FIG. 16) for avoiding interference between the convex portions 23T1, 23T2 and 23T3 and the body portion 44M of the sheet feeding tray 44 when the sheet feeding tray 44 is lifted to the intermediate position (see FIG. 8) are provided on the upstream side of the convex fitting portions 25T1, 25T2 and 25T3 in the sheet feeding direction Z.

[0076] When the sheet feeding tray 44 is lifted above the intermediate position (see FIG. 8, FIG. 9), the gaps A1, A2 and A3 are closed by the convex portions 23T1, 23T2 and 23T3. However, when the sheet feeding tray 44 is lowered below the intermediate position (see FIG. 7), the gaps A1, A2, and A3 are exposed (see FIG. 16), and foreign matter may enter the gaps A1, A2, and A3. Therefore, the document conveying device 120 according to the second embodiment is configured as follows.

[0077] FIG. 13 is a disassembled view showing the fixed wall part 27 and the lifting wall part 29 according to the second embodiment. Hereinafter, differences between the second embodiment and the first embodiment will be described.

[0078] The document conveying device 120 includes the sheet feeding tray 44 on which the documents G are placed; the sheet feeding mechanism 31 which feeds the document G placed on the sheet feeding tray 44 in the predetermined sheet feeding direction Z; the sheet feeding tray lifting mechanism 33 which lifts and lowers the sheet feeding tray 44; the top plate 22 which is provided on the downstream side of the sheet feeding tray 44 in the sheet feeding direction Z and in contact with the lower surface of the documents G to be fed; the fixed wall part 27 which is provided extending downward from the upstream end portion of the top plate 22 in the sheet feeding direction and fixed in position; and the lifting wall part 29 which is provided extending upward from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z, faces the fixed wall part 27 on the upstream side of the fixed wall part 27 in the sheet feeding direction Z, and is lifted and lowered along the fixed wall part 27 together with the sheet feeding tray 44. The lifting wall part 29 has slits 29S1 to 29S along the upper-and-lower direction, the fixed wall part 27 has fins 27F1 to 27F10 along the upper-and-lower direction, the upper end portions of the slits 20S1 to 20S10 are opened in the upper-and-lower direction, and the fins 27F1 to 27F10 protrude upstream of the sheet feeding direction Z and are disposed inside the slits 29S1 to 29S10.

[0079] The fixed wall part 27 is a replacement for the fixed wall part 23 of the first embodiment. The fixed wall part 27 includes a body portion 27A and a plurality of fins 27F1 to 27F10 instead of the convex portions 23T1 to 23T7 and the concave portions 23U1 to 23U6 of the first embodiment. A side wall part 27W and a restriction part 27R have the same functions as the side wall part 23W and the restriction part 23R of the first embodiment.

[0080] The body portion 27A is a rectangular plate-like portion whose thickness direction is along the left-and-right direction and whose longitudinal direction is along the front-and-rear direction. The fins 27F1, 27F2, 27F3, 27F4, 27F5, 27F6, 27F7, 27F8, 27F9, and 27F10 are plate-like portions whose longitudinal direction is along the upper-and-lower direction and whose thickness direction is along the front-and-rear direction. The fins 27F1 to 27F10 are provided on the right surface of the body portion 27A (a surface on the upstream side in the sheet feeding direction Z) and protrude rightward (the upstream side in the sheet feeding direction Z). The fins 27F1 to 27F10 are provided at in intervals in the front-and-rear direction (in the width direction of the document G crossing the sheet feeding direction Z). The upper end portions of the fins 27F1 to 27F10 are inclined so that the downstream side in the sheet feeding direction Z becomes higher. The left end portions of the upper end portions of the fins 27F1 to 27F10 are smoothly connected to the top plate 22.

[0081] The lifting wall part 29 is a replacement for the lifting wall part 25 of the first embodiment. The lifting wall part 29 includes a body portion 29A and a plurality of slits 29S1 to 29S10 instead of the convex fitting portions 25T1 to 25T7 and the concave fitting portions 25U1 to 25U6 of the first embodiment. An end portion 29E and a protrusion 29B have the same function as the end portion 25E and the protrusion 25B of the first embodiment.

[0082] The body portion 29A is a rectangular plate-like portion whose thickness direction is along the left-and-right direction and whose longitudinal direction is along the front-and-rear direction. The slits 29S1, 29S2, 29S3, 29S4, 29S5, 29S6, 29S7, 29S8, 29S9, 29S10 are provided at intervals in the front-and-rear direction, and the fins 27F1 to 27 F10 are provided corresponding to the slits 29S1 to 29S10. The slits 29S1 to 29S10 extend along the upper-and-lower direction and penetrate in the left-and-right direction. The upper end portions of the slits 29S1 to 29S10 are opened in the upper-and-lower direction. The fins 27F1 to 27F10 are disposed inside the slits 29S1 to 29S10.

[0083] The arrangement of the fins 27F1 to 27F10 and the slits 29S1 to 29S10 is determined in accordance with a size of the document G which is supposed to be read by the document conveying device 120. The document G is placed in the center of the sheet feeding tray 44 in the front-and-rear direction. When the document G of the smallest size (for example, A6) is placed with its long side parallel to the sheet feeding direction Z, the most central two fins 27F5 and 27F6 come into contact with the short side of the document G. When the document G of the largest size (for example, A3) is placed with its long side parallel to the sheet feeding direction Z, all the fins 27F1 to 27F10 come into contact with the short side of the document G. That is, the fins 27F1 to 27F10 and the slits 29S1 to 29S10 are arranged so that at least two fins are in contact with the document G placed on the sheet feeding tray 44.

[0084] The edge portions 29R of the slits 29S1 to 29S10 protrude upstream of the sheet feeding direction Z. The tips of the fins 27F1 to 27F10 and the tips of the edge portions 29R on both sides of each of the fins 27F1 to 27F10 form substantially the same plane.

[0085] FIG. 14 is a perspective view showing a state where the lifting wall part 29 according to the second embodiment is positioned at the lower limit position. At this time, the sheet feeding tray 44 is positioned at the lower limit position (a position corresponding to FIG. 7 of the first embodiment), and a capacity of the sheet feeding tray 44 is maximum. When the lifting wall part 29 is positioned at the lower limit position, the lower end portions of the fins 27F1 to 27F10 are positioned slightly below the upper end portions of the slits 29S1 to 29S10. That is, the lower end portions of the fins 27F1 to 27F10 enter the slits 29S1 to 29S10. Among the placed documents G, the documents G facing the lifting wall part 29 are contact in the edge portions 29R of the slits 29S1 to 29S10, and the documents G facing the fixed wall part 27 are contact in the fins 27F1 to 27F10. Since the tips of the fins 27F1 to 27F10 and the tips of the edge portions 29R on both sides of each of the fins 27F1 to 27F10 form substantially the same plane, the downstream ends of the document G in the sheet feeding direction Z are aligned.

[0086] FIG. 15 is a perspective view showing a state where the lifting wall part 29 according to the second embodiment is positioned at the upper limit position. At this time, the sheet feeding tray 44 is positioned at a height higher than the intermediate position (a position corresponding to FIG. 8 in the first embodiment). When the lifting wall part 29 is positioned at the upper limit position, all of the fins 27F1 to 27F10 enter the slits 29S1 to 29S10. Since the tips of the fins 27F1 to 27F10 and the tips of the edge portions 29R on both sides of each of the fins 27F1 to 27F10 form substantially the same plane, the placed document G comes into contact with the fins 27F1 to 27F10 and the edge portions 29R on both sides of each of the fins 27F1 to 27F10.

[0087] FIG. 17 is a view showing the fixed wall part 27, the lifting wall part 29, and the sheet feeding tray 44 according to the second embodiment, as viewed from the right and upper oblique direction. It shows a state in which the lifting wall part 29 and the sheet feeding tray 44 are positioned at the lower limit position. In this embodiment, the body portion 29A of the lifting wall part 29 faces the body portion 27A of the fixed wall part 27 on the upstream side of the body portion 27A of the fixed wall part 27 in the sheet feeding direction Z, and the fins 27F1 to 27F10 are disposed inside the slits 29S1 to 29S10. Therefore, it is not necessary to provide gaps, such as the gaps A1, A2 and A3 of the first embodiment, on the upstream side of the body portion 29A of the lifting wall part 29 in the sheet feeding direction Z. Further, since gaps B1, B2, B3, and B4 of the slits 29S1, 29S2, 29S3, and 29S4 when the lifting wall part 29 is lowered from the upper limit position are smaller than the gaps A1, A2, and A3 of the first embodiment, a possibility of foreign matter entering the gaps B1, B2, B3, and B4 is reduced.

[0088] The document conveying device 120 according to the present embodiment described above includes the sheet feeding tray 44 on which the documents G are placed; the sheet feeding mechanism 31 which feeds the document G placed on the sheet feeding tray 44 in the predetermined sheet feeding direction Z; the sheet feeding tray lifting mechanism 33 which lifts and lowers the sheet feeding tray 44; the top plate 22 provided on the downstream side of the sheet feeding tray 44 in the sheet feeding direction Z and in contact with the lower surface of the document G to be fed; the fixed wall part 27 which is provided extending downward from the upstream end portion of the top plate 22 in the sheet feeding direction Z and fixed in position; and the lifting wall part 29 which is provided extending upward from the downstream end portion of the sheet feeding tray 44 in the sheet feeding direction Z 44, faces the fixed wall part 27 on the upstream side of the fixed wall part 27 in the sheet feeding direction Z, and is lifted and lowered along the fixed wall part 27 together with the sheet feeding tray 44. The lifting wall part 29 has the slits 29S1 to 29S10 along the upper-and-lower direction, and the fixed wall part 27 has the fins 27F1 to 27F10 along the upper-and-lower direction. The upper end portions of the slits 29S1 to S29S10 are opened in the upper-and-lower direction. The fins 29F1 to 29F10 protrude upstream of the sheet feeding direction Z and are disposed inside the slits 29S1 to 29S10.

[0089] According to the present embodiment, a capacity of the sheet feeding tray 44 can be increased without increasing a size in the upper-and-lower direction of the downstream side wall of the sheet feeding tray 44 in the sheet feeding direction Z. Further, in the first embodiment, the gaps A1, A2 and A3 (see FIG. 16) for avoiding interference between the convex portions 23T1, 23T2 and 23T3 and the body portion 44M of the sheet feeding tray 44 when the sheet feeding tray 44 is lifted to the intermediate position (see FIG. 8) are provided on the upstream side of the convex fitting portions 25T1, 25T2 and 25T3 in the sheet feeding direction Z, but in the present embodiment, since there is no need to provide the gap between the lifting wall part 29 and the sheet feeding tray 44, it is possible to prevent foreign matter from entering between the lifting wall part 29 and the sheet feeding tray 44.

[0090] According to the document conveying device 120 according to the present embodiment, the slits 29S1 to 29S10 are provided at intervals in the width direction of the document G crossing the sheet feeding direction Z, the fins 27F1 to 27 F10 are provided corresponding to the slits 29S1 to 29S10, and at least two fins are brought into contact with the document G placed on the sheet feeding tray 44. According to the present embodiment, the document G can be aligned parallel to the sheet feeding direction Z.

[0091] Further, according to the document conveying device 120 according to the present embodiment, the edge portions 29R of the slits 29S1 to 29S10 protrude upstream of the sheet feeding direction Z, and the tip of the fins 27F1 to 27F10 and the tip of the edge portions 29R on both sides of each of the fins 27F1 to 27F10 form the same plane. According to the present embodiment, since the document G is supported by a larger area than a case where the document G is supported only by the fins 27F1 to 27F10, a posture of the document G can be stabilized.

[0092] According to the document conveying device 120 according to the present embodiment, the upper end portions of the fins 27F1 to 27F10 are inclined so that the downstream side in the sheet feeding direction Z becomes higher. According to the present embodiment, the document G can be smoothly fed from the sheet feeding tray 44 to the top plate 22 via the upper end portions of the fins 27F1 to 27 F10.