Abstract:
A sheet containing device including a device frame, a sheet stacking portion that is provided in the device frame and supports sheets, an end regulating portion that abuts against an end of sheets stacked on the sheet stacking portion to perform positional regulation of the sheets, a hitting member that is arranged between the device frame and the end regulating member and moves in accordance with the movement of the end regulating member, and an abutting member for abutting the hitting member in a position to which the hitting member moves, in which deflection of the end regulating member is restricted by the device frame through the hitting member and the abutting member.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a sheet containing device and a sheet feeder having the same, and an image forming apparatus having the sheet feeder, and in particular to a sheet containing device having an end regulating member for regulating movement of sheets stacked on a sheet stacking means.  
           [0003]    2. Related Background Art  
           [0004]    Conventionally, in an image forming apparatus such as a copying machine, a printer, a facsimile machine and a composite apparatus thereof, a sheet feeder for feeding sheets contained in a sheet containing device to an image forming portion is provided.  
           [0005]    Here, as this sheet containing device, there is one having sheet stacking means for staking sheets, a side regulating member for moving in a direction (hereinafter referred to as a cross direction) perpendicular to a sheet feeding direction to regulate side ends of a sheet and a trailing end regulating member for abutting a trailing end of a sheet on the opposite side of the sheet feeding direction to regulate a position in the sheet feeding direction of the sheet. The sheet containing device moves the side regulating member and the trailing end regulating member to predetermined positions, respectively, according to a size of a sheet, thereby performing positioning and movement regulation of the sheet.  
           [0006]    Incidentally, as a method of positioning such a side regulating member, there are known an insertion system that inserts the side regulating member in insertion holes formed in predetermined positions on a bottom surface of a sheet containing device main body and a slide system that provides respectively rack portions in side regulating members arranged so as to be opposed to each other and causes the side regulating members to slide in association with the rack portions via gears engaging with the rack portions.  
           [0007]    However, in the conventional sheet containing device having such a side regulating member, if positioning of the side regulating member is performed by the insertion system, it is difficult to form insertion holes because positions for forming the insertion holes are in close proximity to each other, for example, in a sheet containing device in which letter size (LTR-sized) sheets and A4 size sheets, which have a small dimensional difference in the cross direction, are contained. In addition, if a sheet size is changed, the side regulating member has to be removed from the insertion holes once and then inserted in predetermined positions again, which is extremely laborious.  
           [0008]    On the other hand, if the slide system is used, since a position of the side regulating member can be changed simply by sliding the side regulating member, positioning can be performed easily.  
           [0009]    However, in the slide system, since the rack portions of the side regulating member arranged so as to be opposed to each other are arranged below the sheet stacking means, deflection tends to occur in an abutting portion of the side regulating member that abuts against a sheet. Thus, when a sheet stack is inserted, the abutting portion of the side regulating member may be pressed by the sheet stack and deflected. Then, it is difficult to perform accurate positioning of the sheet stack in the upper part of the side regulating member if the abutting portion is deflected in this manner.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention has been devised in view of such present conditions, and therefore it is an object of the present invention to provide a sheet containing device in which positioning of a regulating member is easy and accurate and positioning of stacked sheets is possible, and a sheet feeder and an image forming apparatus that have the sheet containing device.  
           [0011]    According to the present invention, there is provided a sheet containing device including: a device main body frame; sheet stacking means that is provided within the device main body frame and supports sheets; end regulating means that abuts an end of sheets stacked on the sheet stacking means to perform positional regulation of the sheets; hitting means that is arranged between the device main body frame and the end regulating means and moves in accordance with the movement of the end regulating means; and abutting means for abutting against the hitting means in a position to which the hitting means moves, in which deflection of the end regulating means is regulated by the device main body frame via the hitting means and the abutting means.  
           [0012]    According to the present invention, there is provided a sheet containing device including: a sheet stacking table for supporting a sheet; a side regulating member that is movable in a cross direction of the sheet perpendicular to a sheet feeding direction of the sheet stacked on the sheet stacking table and abuts against a side end of the sheets stacked on the sheet stacking table to perform positional regulation in the cross direction of the sheet; a hitting member that hits against a back surface on the opposite side of a sheet abutting surface of the side regulating member and regulates deflection to the back surface side of the side regulating member; a connecting member that moves the hitting member in a direction perpendicular to a moving direction of the side regulating member in association with a moving operation of the side regulating member; and an abutting portion that is provided on the back surface of the side regulating member and is formed in a shape for abutting against the hitting member moved by the connecting member in a position to which the side regulating member moves to regulate the sheet. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a view showing a schematic structure of an image forming apparatus having a deck type sheet feeder that is an example of a sheet feeder in accordance with a first embodiment of the present invention;  
         [0014]    [0014]FIG. 2 is a perspective view showing a structure of a sheet containing device provided in the sheet feeder (feed deck) shown in FIG. 1;  
         [0015]    [0015]FIG. 3 is a perspective view of the image forming apparatus showing a state in which a door of the sheet feeder shown in FIG. 1 is open;  
         [0016]    [0016]FIG. 4 is a perspective view of the image forming apparatus showing a state in which the door of the sheet feeder shown in FIG. 1 is closed;  
         [0017]    [0017]FIG. 5 is a bottom view of the sheet containing device shown in FIG. 1;  
         [0018]    [0018]FIGS. 6A, 6B and  6 C are main part sectional views showing states at the time of changing a sheet size of the sheet containing device shown in FIG. 1;  
         [0019]    [0019]FIGS. 7A and 7B are bottom views showing states at the time of changing a sheet size of the sheet containing device shown in FIG. 1;  
         [0020]    [0020]FIG. 8 is a perspective view showing a structure of a sheet containing device provided in a sheet feeder in accordance with a second embodiment of the present invention;  
         [0021]    [0021]FIG. 9A is a side view showing a structure of the sheet containing device shown in FIG. 8;  
         [0022]    [0022]FIG. 9B is a sectional view taken along a line IXB-IXB of FIG. 9A;  
         [0023]    [0023]FIGS. 10A and 10C are side views showing states at the time of changing a sheet size of the sheet containing device shown in FIG. 8;  
         [0024]    [0024]FIGS. 10B and 10D are sectional views taken along a line XB-XB and a line XD-XD of FIGS. 10A and 10C;  
         [0025]    [0025]FIG. 11 is a perspective view showing a structure of a sheet containing device provided in a sheet feeder in accordance with a third embodiment of the present invention;  
         [0026]    [0026]FIG. 12A is a side view showing a structure of the sheet containing device shown in FIG. 11;  
         [0027]    [0027]FIG. 12B is a sectional view taken along a line XIIB-XIIB of FIG. 12A;  
         [0028]    [0028]FIGS. 13A and 13C are side views showing states at the time of changing a sheet size of the sheet containing device shown in FIG. 11; and  
         [0029]    [0029]FIGS. 13B and 13D are sectional views taken along a line XIIIB-XIIIB and a line XIIID-XIIID of FIGS. 13A and 13C. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    Embodiments of the present invention will be hereinafter described with reference to the accompanying drawings.  
         [0031]    [0031]FIG. 1 is a view showing a schematic structure of an image forming apparatus having a deck type sheet feeder that is an example of a sheet feeder in accordance with a first embodiment of the present invention.  
         [0032]    In FIG. 1, reference numeral  1  denotes an image forming apparatus main body and reference numeral  2  denotes a deck type sheet feeder (hereafter referred to as a feed deck) attached to the image forming apparatus main body  1 . In addition, reference numeral  1 A denotes an image forming portion that is provided in the image forming apparatus main body  1  and performs image formation by an electrophotographic system. This image forming portion  1 A has a photosensitive drum  14  for forming a toner image, a laser scanner  12  for irradiating light modulated according to an image signal on the photosensitive drum  14 , a transfer roller  15  for transferring a toner image formed on the photosensitive drum  14  to a sheet S, and so on.  
         [0033]    Then, when an image forming operation is started in the image forming portion  1 A having such a structure, first, light modulated according to an image signal is irradiated on the photosensitive drum  14  by the laser scanner  12 , whereby a latent image is formed on the photosensitive drum  14 . Next, this latent image is developed with toner contained in a toner cartridge  13 , whereby a toner image (visible image) is formed on the photosensitive drum  14 .  
         [0034]    When a sheet S is fed from the feed deck  2  in a manner to be described later simultaneously with such a toner image forming operation, this sheet S is transported to a transferring portion, which is constituted of the photosensitive drum  14  and the transfer roller  15 , by a transport roller  11  and a registration roller  11 A in synchronism with the toner image formed on the photosensitive drum  14 . Then, in this transferring portion, the toner image is transferred to the sheet S by applying a bias to the transfer roller  15 .  
         [0035]    Further, the sheet S having the toner image transferred thereon in this manner is thereafter transported to fixing means  16  and heated in this fixing means  16 , whereby the toner image is fixed on the sheet S. Moreover, thereafter, the sheet S is delivered to a delivery portion  18  in the upper part of the apparatus by a delivery roller  17 .  
         [0036]    Incidentally, as shown in FIG. 1, the feed deck  2  comprises: a sheet containing device  3  provided with a sheet stacking table  5  functioning as sheet stacking means for stacking a sheet stack Sa and capable of lifting and lowering in a sheet storage  3   a  for containing sheets S, and provided with regulating members  19 ,  20  and  21  discussed later; sheet feeding means including a feed roller  7  that feeds out an uppermost sheet S 1  of the sheet stack Sa stacked on the sheet stacking table  5  and a separating roller pair  8 ,  9  that is constituted of a feed roller  8  and a retard roller  9  and separates sheets S fed by the feed roller  7 ; and a transport roller  10  for transporting the sheet S separated and fed individually by the separating roller pair  8  and  9  to the image forming apparatus main body  1 .  
         [0037]    Further, the sheet stacking table  5  is suspended by wires  4   a ,  4   b ,  4   c  and  4   d  as shown in FIG. 2. The sheet stacking table  5  moves in the vertical direction (ascends and descends) by winding the wires  4   a ,  4   b ,  4   c  and  4   d  around a wire winding shaft  6  by a driving force of driving means (not shown) such as a motor and unwinding the wires  4   a ,  4   b ,  4   c  and  4   d.    
         [0038]    Moreover, the feed deck  2  has an openable and closable door  2 A that is opened when the sheet stack Sa is stacked on the sheet stacking table  5  as shown in FIG. 3. Then, when the door  2 A is opened as shown in FIG. 3, in this embodiment, the wire winding shaft  6  is rotated in a forward direction by a control portion (not shown) that has detected that the door  2 A is open. The wires  4   a ,  4   b ,  4   c  and  4   d  are unwound by the rotation, and the sheet stacking table  5  descends to a lowermost position as shown in FIG. 3.  
         [0039]    When the stacking of the sheet stack Sa on the sheet stacking table  5  is completed and the door  2 A is closed as shown in FIG. 4, the wire winding shaft  6  is rotated in a backward direction by the control portion (not shown) that has detected that the door  2 A is closed. The wires  4   a ,  4   b ,  4   c  and  4   d  are wound by the rotation, and the sheet stacking table  5  ascends.  
         [0040]    Then, thereafter, the motor (not shown) is controlled by the control portion to wind the wires  4   a ,  4   b ,  4   c  and  4   d  appropriately so as to keep a height of the sheet stacking table  5  at a predetermined position based on a signal from sheet surface detecting means (not shown). This predetermined position is a position where the uppermost sheet S 1  of the stacked sheet stack Sa can be fed by the feed roller  7  and enter a nip of the separating roller pair  8  and  9  smoothly.  
         [0041]    In FIG. 2, reference numeral  19  denotes a reference-side side regulating member functioning as a side regulating member for regulating movement of the sheet S on the sheet stacking table  5  in a cross direction (direction perpendicular to a feeding direction of sheets) and reference numeral  20  denotes a non-reference-side side regulating member. A position in the cross direction of the sheet S on the sheet stacking table  5  is regulated by the reference-side side regulating member  19  and the non-reference-side side regulating member  20  that are provided so as to be opposed to each other on the sheet stacking table  5 . Further, a push-aside plate  20   b  (shown in FIGS. 5 and 6A to  6 C) is provided in the non-reference-side side regulating member  20 . The push-aside plate  20   b  is constituted so as to push stacked sheets to the reference-side regulating member  19  by a spring functioning as an elastic member.  
         [0042]    In addition, reference numeral  21  denotes a trailing end regulating member that is provided on an inner side in a direction of containing sheets and regulates a trailing end of a sheet stack. Moreover, reference numeral  22  denotes an operation lever. When a user moves this operation lever  22 , the side regulating members  19  and  20  and the trailing end regulating member  21  move in association with this operation lever  22 , whereby it is possible to change a size of sheets that can be stacked. Note that, in this embodiment, three types of sheets, namely, LTR (279.4 mm×216 mm), A4 (297 mm×210 mm) and LGL (355.6 mm×216 mm), are stacked on the sheet staking table  5 . Further, the reference-side side regulating member  19  can be provided in a position in the cross direction of a sheet that is the same as a position for transferring an image to the sheet in the cross direction of the sheet in the image forming portion  1 A. The image can be transferred to an accurate position by delivering the sheet along the reference-side side regulating member  19 .  
         [0043]    [0043]FIG. 5 is a view showing a mechanism for operating each of the regulating members  19 ,  20  and  21  that is provided under the sheet stacking table  5 .  
         [0044]    In FIG. 5, reference numeral  23  denotes a board member functioning as a connecting member. This board member  23  is in engagement with the operation lever  22  via a slit portion  24   c  formed diagonally. When the operation lever  22  is moved, for example, in a direction indicated by the arrow “a” in FIG. 5 by this slit portion  24   c , the board member  23  moves in a direction indicated by the arrow “b”, which is a direction perpendicular to a moving direction of the operation lever  22  (see FIG. 7B).  
         [0045]    Here, the trailing end regulating member  21  is connected to the board member  23 . When the board member  23  moves in the direction indicated by the arrow “b” in accordance with the operation of the operation lever  22  as described above, the trailing end regulating member  21  moves in the direction indicated by the arrow “b” (direction opposite to the sheet feeding direction) along a slit (not shown) in association with the movement of the board member  23 .  
         [0046]    The reference-side side regulating member  19  and the non-reference-side side regulating member  20  are provided to move in directions indicated by the arrows “c” and “d”, which are perpendicular to the direction indicated by the arrow “b”, by a sliding mechanism (not shown).  
         [0047]    Slit portions  24   a  and  24   b  that engage with the non-reference-side side regulating member  20  and the reference-side side regulating member  19  are provided in the board member  23 . Sliding portions  19   a  and  20   a  provided in the reference-side side regulating member  19  and the non-reference-side regulating member  20 , respectively, are in engagement with the slit portions  24   a  and  24   b . Consequently, when the board member  23  moves, the two side regulating members  19  and  20 , which are provided so as to be opposed to each other to match the shape of these slit portions  24   a  and  24   b , move symmetrically in the directions indicated by the arrows “c” and “d” in FIG. 5.  
         [0048]    As described above, when the operation lever  22  is operated, the trailing end regulating member  21  and the two side regulating members  19  and  20  move, respectively. Consequently, positioning of the two side regulating members  19  and  20  can be performed easily.  
         [0049]    Moreover, arm members  25   a  and  25   b  as hitting means, which are placed between the two side regulating members  19  and  20  and device frames  26   a  and  26   b  of the feed deck  2 , are provided in this board member  23 . The arm members  25   a  and  25   b  functioning as hitting members are constituted so as to move between the two side regulating members  19  and  20  and the device frames  26   a  and  26   b , which constitute a feed deck main body, in sliding contact with the device frames  26   a  and  26   b  when the board member  23  moves.  
         [0050]    Further, a rib  27  constituting abutting means (abutting portion) for abutting against a projection  251  provided in the arm member  25   a  as shown in FIGS. 6A, 6B and  6 C is provided in the upper part on the back surface of the non-reference-side side regulating member  20  that is the opposite side of a sheet abutting surface thereof that abuts against a sheet stack. Note that, although not illustrated, the arm member  25   b  is formed in the same shape as the arm member  25   a , and a rib that is the same as the rib  27  is provided in the upper part on the back surface of the reference-side side regulating member  19 .  
         [0051]    In this rib  27 , flat portions  27   a  and  27   b  are formed which abut against the projection  251  of the arm member  25   a  in the case in which a sheet of the LTR size shown in FIG. 6A is regulated, stepped portions  27   d  and  27   e  are formed which abut against the projection  251  in the case in which a sheet of the A4 size shown in FIG. 6B is regulated, and flat portions  27   b  and  27   c  are formed which abut against the projection  251  in the case in which a sheet of the LGL size shown in FIG. 6C is regulated. A distance between the flat portions  27   a ,  27   b  and  27   c  and the stepped portions  27   d  and  27   e  is set at 3 mm. In addition, the flat portions  27   a ,  27   b  and  27   c  are smoothly connected by slopes.  
         [0052]    Here, for example, when the non-reference-side side regulating member  20  moves with the reference-side side regulating member  19  from a position for regulating a sheet of the LTR size shown in FIG. 6A to a position for regulating a sheet of the A4 size shown in FIG. 6B in association with movement of the board member  23 , the projection  251  of the arm member  25   a  that has moved with the board member  23  abuts against the stepped portions  27   d  and  27   e  of the rib  27 .  
         [0053]    Then, when the non-reference-side side regulating member  20  moves to the position for regulating a sheet of the A4 size shown in FIG. 6B, the arm member  25   a , which has moved with the board member  23  in a direction perpendicular to the moving direction of the side regulating member  20 , and the rib  27  abut against each other, whereby the two side regulating member  20  are supported from their back side by the arm member  25   a , respectively. In addition, since the arm member  25   a  is in sliding contact with the device frame  26   a , the side regulating member  20  is securely supported by the device frame  26   a  via the arm member  25   a . The reference-side side regulating member  19  is constituted in the same manner.  
         [0054]    Consequently, regardless of a size of a sheet, the two side regulating members  19  and  20  do not deflected toward their back surface side any more even if a large volume of sheets are stacked. As a result, accurate positioning of a sheet stack can be performed in the upper part of the two side regulating members  19  and  20 .  
         [0055]    Next, operations of the three regulating members  19 ,  20  and  21  and the arm members  25   a  and  25   b  in changing stacked sheets will be described. Here, operations for changing sheets from the LTR size to the A4 size and the LGL size will be described.  
         [0056]    [0056]FIG. 5, which has already been described, shows the positions of the three regulating members  19 ,  20  and  21  at the time when sheets of the LTR size are stacked. Note that, in this embodiment, a distance from a sheet feeding position to the trailing end regulating member  21  is set at approximately 279.4 mm and a distance between the side regulating members is set at approximately 216 mm in this case.  
         [0057]    Here, if a user wishes to stack sheets of the A4 size, the user moves the operation lever  22  in the direction indicated by the arrow “a” to a position of A4 shown in FIG. 7A. Then, when the operation lever  22  is moved in this manner, the trailing end regulating member  21  moves in the direction indicated by the arrow “b” in FIG. 5 by the board member  23 . Further, an amount of movement of the trailing end regulating member  21  is approximately 17.6 mm. When the trailing end regulating member  21  moves in this manner, if sheets of the A4 size is stacked, a leading end of the sheets is positioned in the sheet feeding position.  
         [0058]    When the operation lever  22  is moved in the direction indicated by the arrow “a” in this manner, the two side regulating members  19  and  20  move to a position according to the shape of the slits  24   a  and  24   b  provided in the board member  23 . Further, if the sheet size is set as the A4 size in this manner, both the two side regulating members  19  and  20  move to the inside by approximately 3 mm from the LTR position, and the distance between the side regulating members is changed to approximately 210 mm.  
         [0059]    Incidentally, when the board member  23  moves by such an operation of the operation lever  22 , the arm members  25   a  and  25   b  attached to the board member  23  move along the frames  26   a  and  26   b  and the side regulating members  19  and  20 .  
         [0060]    Here, in the A4 position shown in FIG. 6B, the ribs  27  provided in the side regulating members  19  and  20  are offset by 3 mm from the position of the LTR size in the same manner as the shape of the slits  24   b  and  24   a  of the board member  23  below them (see FIG. 7A) changes. Thus, even when the side regulating members  19  and  20  moves to the inside by approximately 3 mm, the arm members  25   a  and  25   b  abut against the projected stepped portions of the ribs  27  provided in the side regulating members  19  and  20 . Further, at this point, the other sides of the arm members  25   a  and  25   b  are always in contact with the device frames  26   a  and  26   b.    
         [0061]    Consequently, deflection to the back surface side of each of the side regulating members  19  and  20  is regulated by the device frames  26   a  and  26   b  via the arm members  25   a  and  25   b . Thus, when sheets S are inserted, even if the side regulating members  19  and  20  are pushed by the weight of the sheets S, each of the side regulating members  19  and  20  does not deflect and sheets of the A4 size can be stacked accurately.  
         [0062]    In changing the sheet size from the A4 size to the LGL size, the operation lever  22  is operated in a direction indicated by the arrow “e” in FIG. 7A to move from the position of the A4 size to the position of the LGL size. Then, by such an operation of the operation lever  22 , the trailing end regulating member  21  moves by 58.6 mm and each of the side regulating members  19  and  20  move to the outside by 3 mm.  
         [0063]    Then, even when each of the side regulating members  19  and  20  are moved in this manner, for example, since the arm member  25   a  abuts against the rib  27  of the non-reference-side side regulating member  20  as shown in FIG. 6C, the non-reference-side regulating member  20  is prevented from being deflected by the weight of the sheets S. Consequently, the sheets of the LGL size can be accurately positioned and stacked.  
         [0064]    In this way, the rib  27  having the stepped portions in the horizontal direction is provided on the back surface of each of the side regulating members  19  and  20 , and the rib  27  is constituted so as to abut against the arm member  25   a  or  25   b  in association with the movement of each of the side regulating members  19  and  20 . Thus, each of the side regulating members  19  and  20  can be prevented from being deflected by the weight of sheets. Consequently, accurate positioning of stacked sheets becomes possible. Further, if the arm members  25   a  and  25   b  are formed of a material with high rigidity, deflection of each of the side regulating members  19  and  20  can be prevented only by the arm members  25   a  and  25   b.    
         [0065]    Next, a second embodiment of the present invention will be described.  
         [0066]    [0066]FIG. 8 is a perspective view showing a structure of a sheet containing device provided in a feed deck in accordance with this embodiment. Note that, in FIG. 8, the reference numerals identical with those in FIG. 2 indicate identical or equivalent portions, and detailed descriptions of such portions will be omitted.  
         [0067]    In FIG. 8, reference numeral  28   a  denotes an arm member moving between the non-reference-side side regulating member  20  and the device frame  26   a . This arm member  28   a  is provided so as to be capable of ascending and descending while abutting against the board member  23  with the aid of gravity. Reference numeral  30  denotes a projection provided on a surface of the board member  23  abutting against the arm member  28   a . In changing a sheet size, when the board member  23  is moved, the arm member  28   a  ascends and descends by this projection  30 .  
         [0068]    In addition, reference numeral  29  denotes a projected shape portion that constitutes an abutting portion provided in the upper part on the back surface of the non-reference-side side regulating member  20 . This projected shape portion  29  has two steps having different projection amounts (stepped portions) in the upper and lower steps. Note that, in this embodiment, a difference between an upper step projection  29   a  and a lower step projection  29   b  is approximately 3 mm. In addition, an arm member of the same structure (not shown) is provided between the reference-side side regulating member  19  and the device frame  26   b.    
         [0069]    Next, operations of the three regulating members  19 ,  20  and  21  and the arm member  28  in changing stacked sheets will be described. Here, operations for changing sheets from the LTR size to the A4 size and the LGL size will be described.  
         [0070]    [0070]FIGS. 9A and 9B show the positions of the three regulating members  19 ,  20  and  21  at the time when sheets of the LTR size are stacked. If the sheet size is changed from this state to the A4 size, the board member  23  moves by approximately 17.6 mm as in the first embodiment. In addition, the side regulating member  20  moves after the slit  24   a  provided in the board member  23  to the inside by 3 mm as in the first embodiment.  
         [0071]    Then, when the board member  23  moves in this manner, the projection  30  provided in the board member  23  moves to a position below the arm member  28   a  as shown in FIGS. 10A and 10B, whereby the arm member  28   a  moves upward. Here, when the arm member  28   a  moves upward in this manner, an upper end of the arm member  28   a  abuts against the upper step projection  29   a  of the projected shape portion  29  provided in the non-reference-side side regulating member  20 .  
         [0072]    Consequently, deflection to the back side of the non-reference-side side regulating member  20  is regulated by the device frame  26   a  via the arm member  28   a . Thus, when sheets S are inserted, even if the non-reference-side side regulating member  20  is pushed by the weight of the sheets S, the non-reference-side side regulating member  20  is not deflected and sheets of the A4 size can be stacked accurately. Note that this operation is the same in the reference-side side regulating member  19 .  
         [0073]    In changing the sheet size from the A4 size to the LGL size, the board member  23  moves by the operation of the operation lever  22 , and with this movement, the projection  30  provided in the board member  23  comes off the arm member  28   a  as shown in FIGS. 10C and 10D. Consequently, the arm member  28   a  descends with the aid of gravity. Then, when the arm member  28   a  descends in this way, the upper side of the arm member  28   a  abuts against the lower step projection  29   b  of the projected shape portion  29  provided in the reference-side side regulating member  20 . Thus, deflection to the back surface side of the non-reference-side side regulating member  20  can be regulated by the device frame  26   a  via the arm member  28   a  in a position offset by 3 mm from the A4 size as in the case of the LTR size.  
         [0074]    In this way, the projected shape portion  29  having the stepped portions in the vertical direction is provided on the back surface of each of the side regulating members  19  and  20 , and the projected shape portion  29  is constituted so as to abut against the arm member  28   a  that moves in association with the movement of each of the side regulating members  19  and  20 . Thus, each of the side regulating members  19  and  20  is prevented from being deflected due to a weight of sheets, or the like. Consequently, accurate positioning of stacked sheets becomes possible.  
         [0075]    Next, a third embodiment of the present invention will be described.  
         [0076]    [0076]FIG. 11 is a perspective view showing a structure of a sheet containing device provided in a feed deck in accordance with this embodiment. Note that, in FIG. 11, the reference numerals identical with those in FIG. 2 indicate identical or equivalent portions.  
         [0077]    In FIG. 11, reference numeral  31   a  denotes an arm member moving between the non-reference-side side regulating member  20  and the device frame  26   a . This arm member  31   a  is rotatably connected to a shaft  31   b  provided on each of the side regulating members  19  and  20 . In addition, reference numeral  32  denotes a projected shape portion of an arc shape provided in the upper part on the back surface of the non-reference-side side regulating member  20 . This projected shape portion  32  is a stepped portion having two steps in which a central part  32   b  is more projected than both end parts  32   a  and  32   c . In this embodiment, a difference of projection amounts of the central part  32   b  and both the left and right end parts  32   a  and  32   c  is approximately 3 mm.  
         [0078]    Here, an engaging portion  33  engaging with the arm member  31   a  is provided in the board member  23 . The arm member  31   a  rotates about the shaft  31   b  with the movement of the board member  23 . In addition, an arm member of the same structure (not shown) is provided between the reference-side side regulating member  19  and the device frame  26   b.    
         [0079]    Next, operations of the three regulating members  19 ,  20  and  21  and the arm member  31   a  in changing stacked sheets will be described. Here, operations for changing sheets from the LTR size to the A4 size and the LGL size will be described.  
         [0080]    [0080]FIGS. 12A and 12B show the positions of the three regulating members  19 ,  20  and  21  at the time when sheets of the LTR size are stacked. If the sheet size is changed from this state to the A4 size, the board member  23  moves by approximately 17.6 mm as in the first embodiment. In addition, the side regulating member  20  moves after the slit provided in the board member  23  to the inside by 3 mm as in the first embodiment.  
         [0081]    Then, when the board member  23  moves in this manner, the arm member  31   a  rotates in a direction indicated by the arrow in FIG. 13A with the movement of the board member  23 , and the upper end of the arm member  31   a  moves so as to abut against the central part  32   b  from the end part  32   a  of the arc-shaped projected shape portion  32  provided in the non-reference-side side regulating member  20 .  
         [0082]    Consequently, deflection to the back surface side of the non-reference-side side regulating member  20  is regulated by the device frame  26   a  via the arm member  31   a . Thus, when sheets S are inserted, even if the non-reference-side side regulating member  20  is pushed by the weight of the sheets S, the non-reference-side side regulating member  20  is not deflected and sheets of the A4 size can be stacked accurately. Note that this operation is the same in the reference-side side regulating member  19 .  
         [0083]    In changing the sheet size from the A4 size to the LGL size, the board member  23  moves by the operation of the operation lever  22 . Consequently, the arm member  31   a  rotates to the position shown in FIGS. 13C and 13D. Then, when the arm member  31   a  rotates in this manner, the upper side of the arm member  31   a  abuts against the end part  32   c  of the projected shape portion  32  provided in the reference-side side regulating member  20 . Thus, deflection to the back surface side of the non-reference-side side regulating member  20  can be regulated by the device frame  26   a  via the arm member  31   a  in a position offset by 3 mm from the A4 size as in the case of the LTR size.  
         [0084]    In this way, the arc-shaped projected shape portion  32  having the stepped portions is provided on the back surface of each of the side regulating members  19  and  20 , and the projected shape portion  32  is constituted so as to abut against the arm member  31   a  that moves in association with the movement of each of the side regulating members  19  and  20 . Thus, each of the side regulating members  19  and  20  is prevented from being deflected due to a weight of sheets, or the like. Consequently, accurate positioning of stacked sheets becomes possible.  
         [0085]    Further, in each of the above-mentioned embodiments, the arm members  25   a  ( 25   b ),  28   a  ( 28   b ), and  31   a  ( 31   b ) are moved along the device frames  26   a  and  26   b  in the horizontal direction, in the vertical direction and in the rotation direction, respectively, and the ribs  27 , the projected shaped portion  29  and the projected shaped portion  32  are provided in the side regulating members  19  and  20  that abut against the arm members. However, conversely, the arm members  25   a  ( 25   b ),  28   a  ( 28   b ), and  31   a  ( 31   b ) may be moved along the side regulating members  19  and  20  in the horizontal direction, in the vertical direction and in the rotation direction, respectively, and the ribs  27 , the projected shaped portion  29  and the projected shaped portion  32  that abut against the arm members may be provided in the device frames  26   a  and  26   b.