Patent Publication Number: US-2022234846-A1

Title: Sheet feeding cassette and image forming apparatus

Description:
INCORPORATION BY REFERENCE 
     This application is based on and claims the benefit of priority from Japanese patent application No. 2021-010333 filed on Jan. 26, 2021, which is incorporated by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a sheet feeding cassette which stores a sheet on which an image is to be formed and an image forming apparatus. 
     In an image forming apparatus such as a multifunctional peripheral and a printer, a sheet is fed from a sheet feeding cassette to an image forming part in a predetermined sheet feeding direction. The sheet feeding cassette includes a liftable and lowerable lift plate on which the sheet is placed and a pair of side cursors which aligns the placed sheets in a width direction perpendicular to the sheet feeding direction. 
     The pair of side cursors are moved in the width direction to align the sheets. Therefore, the lift plate has notches through which the side cursors are passed. In some cases, the notch may be formed at one or more places of the lift plate. In other words, the lift plate may be formed into a branched shape. 
     In the above-described sheet feeding cassette, in order to align the small-sized sheets, the pair of side cursors is disposed on the downstream side in the sheet feeding direction (a side closer to a sheet feeding device). That is, the notch is disposed on the downstream side in the sheet feeding direction. If the notch is disposed in the above-described manner, the sheets may not be placed on the lift plate stably. 
     For example, in a case where a large number of large-sized sheets are placed (for example, 4000 sheets), the downstream side portions of the sheets in the sheet feeding direction overlap with the notch. In this case, the downstream side portions of the sheets may be deformed without being supported by the lift plate, and the sheet may not be fed stably. On the other hand, the side cursors may be provided with a notch through which the branched shape lift plate is passed. However, in this case, when the number of the sheets is large, the size of the notch becomes large, and it becomes difficult to secure the strength of the side cursor. 
     SUMMARY 
     In accordance with an aspect of the present disclosure, a sheet feeding cassette includes a main body, a lift plate, a pair of side cursors, and an auxiliary lift plate. The main body is configured to accommodate a sheet fed out in a predetermined sheet feeding direction. The lift plate is provided in the main body in a liftable manner, and has a sheet placement surface on which the sheet is placed. The pair of side cursors is configured to be moved in a width direction perpendicular to the sheet feeding direction and to come into contact with side edges of the sheet placed on the lift plate to align the sheet. The auxiliary lift plate is detachably attached to a notch portion which is formed in the lift plate so as to allow a moving of the side cursors. 
     In accordance with an aspect of the present disclosure, an image forming apparatus includes the sheet feeding cassette; an apparatus main body to which the sheet feeding cassette is detachably attached; a sheet feeding device which feeds the sheet from the sheet feeding cassette attached to the apparatus main body; and an image forming part which forms an image on the sheet fed from the sheet feeding cassette by the sheet feeding device. 
     The other features and advantages of the present disclosure will become more apparent from the following description. In the detailed description, reference is made to the accompanying drawings, and preferred embodiments of the present disclosure are shown by way of example in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view schematically showing inner structures of an image forming apparatus and a large capacity deck according to one embodiment of the present disclosure. 
         FIG. 2  is a perspective view schematically showing the large capacity deck according to the embodiment of the present disclosure. 
         FIG. 3  is a plan view showing the large capacity deck (in a state where an auxiliary lift plate is detached) according to the embodiment of the present disclosure. 
         FIG. 4  is a plan view showing the large capacity deck (in a state where the auxiliary lift plates are attached) according to the embodiment of the present disclosure. 
         FIG. 5  is a sectional view taken along the line III-III in  FIG. 4 . 
         FIG. 6  is a perspective view showing an attachment recess of a lift plate, in the large capacity deck according to the embodiment of the present disclosure. 
         FIG. 7  is a perspective view showing a stopper mechanism of a side cursor and the auxiliary lift plate supported by the side cursor, in the large capacity deck according to the embodiment of the present disclosure. 
         FIG. 8A  is a plan view showing the auxiliary lift plate, in the large capacity deck according to the embodiment of the present disclosure. 
         FIG. 8B  is a perspective view showing a coupling recess and a coupling hook of the auxiliary lift plate, in the large capacity deck according to the embodiment of the present disclosure. 
         FIG. 9  is a perspective view showing the auxiliary lift plate and the lift plate in the large capacity deck according to the embodiment of the present disclosure, in a middle of a procedure for attaching the auxiliary lift plate to the lift plate. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, with reference to the attached drawings, an image forming apparatus and a large capacity deck according to one embodiment in the present disclosure will be described. 
     First, with reference to  FIG. 1 , an entire structure of the image forming apparatus  1  will be described.  FIG. 1  is a front view schematically showing an inner structure of the image forming apparatus  1 . In the following description, a front side of the paper plane on which  FIG. 1  is drawn is defined as a front side of the image forming apparatus  1 . Fr, Rr, L, R, Up and Lo marked in each drawing indicate the front side, the rear side, the left side, the right side, the upper side and the lower side of the image forming apparatus  1 , respectively. 
     The apparatus main body  3  of the image forming apparatus  1  includes a sheet feeding part  5 , an electrophotographic type image forming part  7 , and a discharge tray  9 . Further, the apparatus main body  3  is formed with a conveyance path  11  along which the sheet is conveyed upward from the sheet feeding part  5  to the discharge tray  9  through the image forming part  7 . 
     A large capacity deck  15  is connected to the image forming apparatus  1 . The large capacity deck  15  can store a large number of sheets (for example, 4000 sheets). When the large capacity deck  15  is connected to the image forming apparatus  1 , the sheet can be fed to the conveyance path  11  of the image forming apparatus  1 . The large capacity deck  15  is an example of a sheet feeding cassette of the present disclosure. 
     Next, with reference to  FIG. 2  to  FIG. 6 , the large capacity deck  15  will be described.  FIG. 2  is a perspective view showing a main body  21  of the large capacity deck  15 , and  FIG. 3  and  FIG. 4  are plan views showing the main body  21  of the large capacity deck  15 .  FIG. 3  shows the main body  21  in a state where an auxiliary lift plate  26  is detached, and  FIG. 4  shows the main body  21  in a state where auxiliary lift plates  26  are attached.  FIG. 5  is a sectional view taken along the line III-III in  FIG. 4 .  FIG. 6  is a perspective view showing an attachment recess  41  of a lift plate  23 . 
     As shown in  FIG. 2 ,  FIG. 3  and  FIG. 4 , the large capacity deck  15  includes the main body  21  configured to accommodate the sheet, the lift plate  23  provided in the main body  21  and on which the sheets are placed, a pair of side cursors  25  ( 25 F and  25 R) provided in the main body  21  and which aligns the sheets placed on the lift plate  23 , and the auxiliary lift plates  26  (see  FIG. 4 ) attachable to and detachable from the lift plate  23 . In the present embodiment, the sheet is fed along a sheet feeding direction X from the right side to the left side in  FIG. 3  and  FIG. 4 . In the following description, the upstream and the downstream shows the upstream and the downstream in the sheet feeding direction X. Further, a direction (the front-and-rear direction) crossing to the sheet feeding direction X is referred to as a width direction Y, and the upper-and-lower direction (the vertical direction) is referred to as the upper-and-lower direction Z. The large capacity deck  15  is further provided with a coupling part (not shown) to which the image forming apparatus  1  is coupled and a sheet feeding device  12  which feeds the sheet placed on the lift plate  23  to the image forming apparatus  1 . 
     The main body  21  has a size capable of placing a large number of (for example, 4000 sheets) the largest size sheets (for example, a A3 size sheet) on which an image is to be formed by the image forming part  7  of the image forming apparatus  1 . In the upstream and downstream end portions of the side plates of the main body  21 , slits  21   a  are formed along the upper-and-lower direction. 
     As shown in  FIG. 3 , guide rails  31  are supported on the downstream side portion of the bottom plate of the main body  21  along the width direction Y. The guide rails  31  are disposed on the upstream side and the downstream side on one side and the other side with respect to the center in the width direction Y. Further, on one side (the front side in this example) with respect to the center in the width direction Y, a stopper rod  33  is supported along the width direction Y between the upstream side and downstream side guide rails  31 . 
     The lift plate  23  is a plate-like member having a size capable of placing the largest size sheet, and as shown in  FIG. 5  and  FIG. 6 , is formed of a placement part  23 X on which the sheets are placed, and a peripheral edge part  23 Y bent downward from the peripheral edge of the placement part  23 X at substantially right angles to the placement part  23 X. The upper surface of the placement part  23 X functions as a sheet placement surface. 
     As shown in  FIG. 3  and  FIG. 4 , the lift plate  23  has an upstream side portion  23   a , a downstream side portion  23   b , and a central portion  23   c  between the upstream side portion  23   a  and the downstream side portion  23   b . The upstream side portion  23   a  and the downstream side portion  23   b  have a rectangular planar shape long in the width direction Y and short in the sheet feeding direction X. The upstream side portion  23   a  and the downstream side portion  23   b  have the same width, and the length of the downstream side portion  23   b  is shorter than the length of the upstream side portion  23   a . The central portion  23   c  is formed at the center of the width direction Y along the sheet feeding direction X. The central portion  23   c  has a width shorter than the upstream side portion  23   a  and the downstream side portion  23   b , and is narrower than the width of the smallest size sheet (for example, a postcard). 
     In the above-described configuration, rectangular notch portions  37  are formed on both sides of the central portion  23   c  in the width direction Y. As shown in  FIG. 3 , through the notch portions  37 , the guide rails  31  and the stopper rod  33  of the main body  21  are exposed. Further, the central portion  23   c  and the upstream side portion  23   a  has a rectangular opening  39  at the center in the width direction Y along the sheet feeding direction X. 
     As shown in  FIG. 3 , around the peripheral edge of each notch portion  37 , a plurality of attachment recesses  41  ( 41   a ,  41   b  and  41   c ) are formed. In detail, the attachment recess  41  contains the two attachment recesses  41   a  and  41   b  formed around each end edge along the width direction Y, and the two attachment recesses  41   c  formed around the side edge along the sheet feeding direction X. The attachment recess  41   a  is disposed outside the attachment recess  41   b  in the width direction Y. The two attachment recesses  41   c  are disposed on the upstream end portion and the downstream end portion of the side edge. 
     As shown in  FIG. 6 , each attachment recess  41  has a rectangular recess  43  recessed from the placement part  23 X (the sheet placement surface), a rectangular opening  45  formed in the recess  43  at the corner between the placement part  23 X and the peripheral edge part  23 Y, and a projection piece  47  projecting upward from the lower edge of the opening  45 . The depth of the recess  43  is smaller than the plate thickness of the lift plate  23 . The depth of the recess  43  of the attachment recess  41   a  disposed outside in the width direction Y is deeper than the recess  43  of the attachment recess  41   b  disposed inside in the width direction Y. The upper end surface of the projection piece  47  is flat and formed below the bottom surface of the recess  43 . 
     As shown in  FIG. 3  and  FIG. 4 , at the four corners of the lift plate  23 , pins  51  protruding in the width direction Y are provided. As shown in  FIG. 2 , the pins  51  are protruded outside the main body  21  through the slits  21   a  formed in the side plates of the main body  21 . To each pin  51 , a wire  52  is connected. The wires  52  are connected to a winding roller  54  via pullies  53 . When the winding roller  54  is rotated in one direction, the wires  52  are wound around the winding roller  54  to lift the lift plate  23  with the horizontal posture. The lift plate  23  is lifted until the uppermost sheet of the stacked sheets can be fed by the sheet feeding device (not shown). On the other hand, when the winding roller  54  is rotated in the counter direction, the wires  52  are fed from the winding roller  54  to lower the lift plate  23  with the horizontal posture. The lift plate  23  is lowered until it reaches the bottom plate of the main body  21 . 
     Next, the pair of side cursors  25  ( 25 F,  25 R) will be described with reference to  FIG. 7  in addition to  FIG. 3  and  FIG. 4 .  FIG. 7  is a perspective view showing a stopper mechanism or the like of the side cursor  25 . 
     As shown in  FIG. 3  and  FIG. 4 , the pair of side cursors  25  includes a front cursor  25 F and a rear cursor  25 R, and each of the front cursor  25 F and the rear side cursor  25 R has a side wall part  55  upright to the bottom plate of the main body  21  and an engagement part  57  along the bottom plate of the main body  21 . 
     As shown in  FIG. 7 , the side wall part  55  has a vertical wall  55   a  having the predetermined length along the sheet feeding direction X and the predetermined height along the upper-and-rear direction Z, and an upper wall  55   b  and a lower wall  55   c  bent outward in the width direction Y from the upper edge and the lower edge of the vertical wall  55   a . The length of the side wall part  55  along the sheet feeding direction X is slightly shorter than the length of the notch portion  37  of the lift plate  23  (see  FIG. 3  and  FIG. 4 ), and the height of the side wall part  55  along the upper-and-lower direction Z is higher than the height of the sheets of the maximum capacity. 
     The engagement part  57  extends in the width direction Y from the upstream side end portion of the lower edge of the side wall part  55  toward the center of the width direction Y. As shown in  FIG. 3 , a rack gear is formed along the downstream side edge of the engagement part  57  of the front cursor  25 F, and a rack gear is formed along the upstream side edge of the engagement part  57  of the rear cursor  25 R. 
     The front and rear cursors  25 F and  25 R are arranged in the notch portions  37  of the lift plate  23  so that the respective side wall parts  55  face each other in the width direction Y. Each engagement part  57  is slidably supported by the guide rails  31  of the main body  21 . The rack gear of each engagement part  57  is engaged with a pinion gear (not shown) supported by the bottom plate of the main body  21 . The stopper rod  33  of the main body  21  penetrates the lower end portion of the side wall part  55  of the front cursor  25 F. 
     When the side wall part  55  of the front cursor  25 F is moved in one direction, the engagement part  57  is slid along the guide rail  31  together with the side wall part  55  to rotate the pinion gear, and the engagement part  57  of the rear cursor  25 R is moved in the other direction along the guide rail  31 . Since each engagement part  57  is provided with a bearing (not shown), each engagement part  57  moves smoothly. As a result, both the side wall parts  55  slides synchronously in the direction of away from or close to each other. At this time, the side wall parts  55  pass through the notch portions  37  of the lift plate  23 . The side wall parts  55  slide in the direction close to each other, and the vertical wall  55   a  comes into contact with the side edges of the sheets placed on the lift plate  23 , whereby the sheets are aligned with respect to the center in the width direction Y. Thus, the inner surface of the vertical walls  55   a  function as a regulating surface for aligning the position of the sheets. 
     The pair of side cursors  25  is provided with a stopper mechanism which locks the side cursors  25  at the predetermined position. As shown in  FIG. 7 , the stopper mechanism includes an operation arm  61  and an engagement arm  62  which are long in the upper-and-lower direction and are operated together, and is disposed outside the vertical wall  55   a  of the side wall part  55  of the front cursor  25 F. The operation arm  61  has a length longer than the engagement arm  62 . The center portion of the operation arm  61  is supported by a turning shaft  63  provided along the sheet feeding direction X in a turnable manner. Thereby, the operation arm  61  is turned around the turning shaft  63 . The upper end portion of the operation arm  61  is provided with a grip  65  which is operated by a user. The grip  65  is exposed through an opening formed in the upper wall  55   b  of the side wall part  55 . The operation arm  61  is biased by a biasing member (not shown) such that the upper portion above the turning shaft  63  turns outward and the lower portion below the turning shaft  63  turns inward. 
     The engagement arm  62  is disposed below the operation arm  61 . The center portion of the engagement arm  62  is supported by a turning shaft  64  provided along the sheet feeding direction X in a turnable manner. As a result, the engagement arm  62  is turned around the turning shaft  64 . The upper end portion of the engagement arm  62  overlaps with the lower end portion of the operation arm  61  from the outside. An opening  67  along the width direction Y is formed at the lower end portion of the engagement arm  62 . The stopper rod  33  penetrating through the side wall part  55  is inserted into the opening  67 . The engagement arm  62  is biased by a biasing member (not shown) such that the upper portion above the turning shaft  64  turns inward and the lower portion below the turning shaft  64  turns outward. Thus, the peripheral edge of the opening  67  is engaged with the stopper rod  33 , and the engagement arm  62  is immovable with respect to the stopper rod  33  by friction between them. That is, since the front cursor  25 F is immovable, the sliding of the pair of side cursors  25  is restricted. 
     When the grip  65  of the operation arm  61  is pulled inward to turn the operation arm  61  around the turning shaft  63 , the lower end portion of the operation arm  61  pushes the upper end portion of the engagement arm  62  outward to turn the engagement arm  62  around the turning shaft  64 . Thus, the peripheral edge of the opening  67  separates from the stopper rod  33 . That is, the engagement of the engagement arm  62  with the stopper rod  33  is released. As a result, the front cursor  25 F is allowed to be moved so that the sliding of the pair of side cursors  25  is allowed. In the above manner, after the side cursors  25  are slid to the predetermined position while pulling the grip  65  of the operation arm  61  inward, when the grip  65  is released, the peripheral edge of the opening  67  of the engagement arm  62  is engaged with the stopper rod  33 , and the side cursors  25  are immovable to lock the side cursors  25  at the predetermined position. 
     Next, with reference to  FIG. 4 ,  FIG. 8A  and  FIG. 8B , the auxiliary lift plate  26  will be described.  FIG. 8A  is a plan view showing the auxiliary lift plate  26 , and  FIG. 8B  is a perspective view showing a coupling recess  101  and a coupling hook  71  of the auxiliary lift plate  26 . 
     As shown in  FIG. 4 , the auxiliary lift plate  26  includes two auxiliary lift pieces  27  attached to one notch portion  37  of the lift plate  23  and two auxiliary lift pieces  27  attached to the other notch portion  37  of the lift plate  23 . The auxiliary lift pieces  27  have the same structure. 
     As shown in  FIG. 8A  and  FIG. 8B , the auxiliary lift piece  27  is a rectangular plate-shaped piece having the same length as the length of the notch portion  37 , a width shorter than the width of the notch portion  37  and the same thickness as the thickness of the lift plate  23 . As shown in  FIG. 8B , the auxiliary lift piece  27  is formed with a placement part  27 X on which the sheets are placed, and a peripheral edge part  27 Y bent downward from the peripheral edge of the placement part  23 X at substantially right angles to the placement part  27 X. The upper surface of the placement part  27 X functions as a sheet placement surface. 
     Around the peripheral of the auxiliary lift piece  27 , a plurality of coupling hooks  71  ( 71   a ,  71   b ) and a plurality of coupling recesses  101 . As shown in  FIG. 8A , the coupling hooks  71  contains the coupling hooks  71   a  formed around one side edge at the predetermined interval, and the coupling hook  71   b  formed around both end edges opposite to the one side edge. The coupling recess  101  is formed around the other side edge at the predetermined interval. 
     As shown in  FIG. 8B , the coupling hook  71  has an extension portion  73  extending outward from the placement part  27 X and a bent portion  75  bent downward from the tip end of the extension portion  73  at substantially right angles. On both sides of the extension portion  73 , notches  77  are formed. 
     The coupling recess  101  has the same structure as the attachment recess  41  (see  FIG. 6 ) of the lift plate  23 , and has a rectangular recess  103  recessed from the placement part  27  (the sheet placement surface), a rectangular opening  105  formed in the recess  103  at the corner between the placement part  27 X and the peripheral edge part  27 Y, and a projection piece  107  projecting upward from the lower edge of the opening  105 . The upper end surface of the projection piece  107  is flat and formed below the bottom surface of the recess  103 . 
     Referring again to  FIG. 3  and  FIG. 4 , the main body  21  is provided with an end cursor  81 . The end cursor  81  is disposed at the center of the bottom plate of the main body  21  in the width direction Y. The end cursor  81  is supported by the main body  21  in a slidable manner along the sheet feeding direction X through the opening  39  of the lift plate  23 . 
     A procedure for placing the sheets to the large capacity deck  15  having the above configuration will be described with reference to  FIG. 3  to  FIG. 5  and  FIG. 9 .  FIG. 9  is a perspective view showing the lift plate  23  and the auxiliary lift plate  26  in a middle of the procedure for placing the sheets to the large capacity deck  15 . In an initial state (a state where the sheets are not placed), the side cursors  25  are slid to the outermost (see  FIG. 3 ). 
     In a case where the smallest size sheets (for example, a postcard) are placed on the lift plate  23 , as shown in  FIG. 3 , the auxiliary lift plate  26  is not attached to the lift plate  23 . The sheets are mainly placed on the downstream side portion  23   b  and the central portion  23   c  of the lift plate  23 . After the sheet is placed, the stopper mechanism of the pair of side cursors  25  is released (see  FIG. 7 , the grip  65  of the operation arm  61  is pulled inward), one side cursor  25  is moved such that the vertical walls  55   a  (see  FIG. 7 ) of the side wall parts  55  of the side cursors  25  are brought into contact with the side edges of the sheets. As a result, the sheets are aligned at the center in the width direction Y. Further, the end cursor  81  is moved to come into contact with the end edges of the sheets. Thereafter, the lift plate  23  is lifted until the uppermost sheet of the stacked sheets reaches the sheet feeding position. 
     In a case where the largest size sheets (for example, an A3 size sheet) are placed on the lift plate  23 , the sheets are placed on the upstream side portion  23   a , the central portion  23   c  and the downstream side portion  23   b  of the lift plate  23 , and the downstream portions of the sheets overlap with the notch portions  37 . If the placed sheets overlap with the notch portions  37 , the sheets may be deformed as described above. Especially, if the number of the sheets is large, the possibility that the sheets are deformed becomes high. Then, in this case, the auxiliary lift plate  26  is attached to the lift plate  23 . In the embodiment, a case where two auxiliary lift pieces  27  are attached to each notch portion  37  will be described. 
     First, the coupling hooks  71  of the first auxiliary lift piece  27  are coupled to the attachment recesses  41  of the lift plate  23 . In detail, two coupling hooks  71   a  formed around the side edge of the first auxiliary lift piece  27  are engaged with two attachment recesses  41   c  formed around the side edge of the notch portion  37  of the lift plate  23 , and the coupling hooks  71   b  formed around the end edges of the first auxiliary lift piece  27  are engaged with the inner attachment recesses  41   b  formed around the end edges of the notch portion  37  of the lift plate  23 . At this time, as shown in  FIG. 9 , the bent portion  75  of the coupling hook  71  is inserted into the opening  45  of the attachment recess  41 . Then, the extension portion  73  of the coupling hook  71  is placed on the upper end surface of the projection piece  47  of the attachment recess  41 . Because the upper end surface of the projection piece  47  is below the bottom surface of the recess  43 , as shown in  FIG. 5 , the sheet placement surface of the placement part  27 X of the first auxiliary lift piece  27  is lower than the sheet placement surface of the placement part  23 X of the lift plate  23 . 
     Next, the coupling hooks  71  of the second auxiliary lift piece  27  are coupled to the attachment recesses  41  of the lift plate  23  and the coupling recesses  101  of the first auxiliary lift piece  27 . In detail, two coupling hooks  71   a  formed around the side edge of the second auxiliary lift piece  27  are engaged with two coupling recesses  101  formed around the side edge of the first auxiliary lift piece  27 , and the coupling hooks  71   b  formed around the end edges of the second auxiliary lift piece  27  are engaged with the outer attachment recesses  41   a  formed around the end edges of the notch portion  37  of the lift plate  23 . As a result, the lift auxiliary pieces  27  are connected to each other, and are arranged side by side in the width direction. As described above, the sheet placement surface of the placement part  27 X of the first auxiliary lift piece  27  is lower than the sheet placement surface of the placement part  23 X of the lift plate  23 . Further, the depth of the recess  43  of the outer attachment recess  41   a  is deeper than the depth of the recess  43  of the inner attachment recess  41   a . Then, as shown in  FIG. 5 , the sheet placement surface of the placement part  27 X of the second auxiliary lift piece  27  is lower than the sheet placement surface of the placement part  27 X of the first auxiliary lift piece  27 . 
     After the two lift auxiliary pieces  27  are attached to each notch portion  37 , the sheets are placed on the lift plate  23 . Since the downstream portions of the sheets are supported by the lift plate  23  and the auxiliary lift plate  26 , the sheets can be placed without being deformed. After the sheets are placed, the stopper mechanism of the pair of side cursors  25  is released in the above-described manner, and one of the side cursors  25  is moved so that the vertical walls  55   a  of the side walls  55  of the pair of side cursors  25  are brought into contact with the side edges of the sheets. Thus, the sheets are aligned at the center in the width direction Y. Further, the end cursor  81  is moved to come into contact with the end edges of the sheets. Thereafter, the lift plate  23  is lifted until the uppermost sheet of the placed sheets reaches the sheet feeding position. 
     As described above, according to the present disclosure, by attaching the auxiliary lift plates  26  to the notch portions  37  of the lift plate  23 , the large size sheets can be lifted and lowered without being deformed. Therefore, it becomes possible to feed the sheet stably. Additionally, the auxiliary lift plate  26  can be attached to and detached from the lift plate  23  by a simple work such as engagement of the coupling hook  71  with the attachment recess  41  or the coupling recess  101 . 
     Since the height of the sheet placement surface of the auxiliary lift plate  26  is lower than the height of the sheet placement surface of the lift plate  23 , the side edges of the sheets can be prevented from being caught in a gap between the lift plate  23  and the auxiliary lift plate  26  or a gap between the auxiliary lift pieces  27 . 
     Further, since the auxiliary lift pieces  27  have the same shape, the number of auxiliary lift pieces  27  to be attached to the notch portion  37  can be changed according to the size of the sheet. For example, in the case of a sheet of a relatively small size, one auxiliary lift piece  27  may be attached to each notch portion  37 . Further, the number of the auxiliary lift pieces  27  attachable to the notch portion  37  is not limited to two, but may be three or more. Further, the plurality of auxiliary lift pieces  27  may be different in width. In this case, the attachment recesses  41  of the lift plate  23  are arranged to correspond to the coupling hooks  71  of the auxiliary lift piece  27 . 
     Next, a modified example of the present disclosure will be described with reference to  FIG. 7 . In this modified example, one side cursor  25 F is provided with a support plate  91  capable of supporting the auxiliary lift piece  27 . 
     The support plate  91  is provided on the outside surface of the vertical wall  55   a  of the side wall part  55  of one side cursor  25 F between the upper and lower walls  55   b  and  55   c  along the upper-and-lower direction Z. In the support plate  91 , an opening  92  having a dimension capable of accommodating the auxiliary lift piece  27  is formed along the upper-and-lower direction Z. On one longitudinal edge of the opening  92 , two hook pieces  93  are formed at the predetermined interval. On the other longitudinal edge of the opening  92 , two protrusions  95  are formed at the predetermined interval. The support plate  91  is an example of an accommodation portion of the auxiliary lift plate  26  in the present disclosure. 
     The extension portion  73  and the bent portion  75  of each coupling hook  71  of the auxiliary lift piece  27  are engaged with the hook pieces  93 , and the protrusions  95  of the support plate  91  are engaged with the openings  105  of the coupling recesses  101  of the auxiliary lift piece  27  so that the auxiliary lift piece  27  is accommodated by the support plate  91 . A plurality of the support plates  91  may be formed on the side cursor  25 . 
     Thus, since it is not necessary to newly provide a storage place for the auxiliary lift piece  27 , the management of the auxiliary lift plate  26  is facilitated. 
     Although the present disclosure has been described with respect to specific embodiments, the present disclosure is not limited to the embodiments described above. Those skilled in the art will be able to modify the above embodiments without departing from the scope and spirit of the present disclosure.