Patent Publication Number: US-7900910-B2

Title: Sheet package

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Application claims priority from Japanese Patent Application No. 2006-297022, filed Oct. 31, 2006, the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     The present disclosure relates to a sheet package, and more particularly to a sheet package that has a package member to protect an exterior of a stack of sheets, and that can be loaded in a printer together with the package member. 
     Conventionally, a sheet package has been known which stores a stack of sheets in a box-like package member. When the sheets are used for printing, a lid portion of the package member may be opened and folded back to the opposite side and the sheets may be set in the printer together with the packaging member (see, for example, Japanese Patent Application Laid-Open Publication No. 2003-285939). Because this conventional sheet package allows users to handle a plurality of sheets in the unit of a package, the usability is improved. Moreover, because the sheet package can protect sheets inside by covering them with the package member, the sheet package is especially useful when heat-sensitive sheets, which are particularly susceptible to light and heat, are employed. 
     The conventional sheet package has a rectangular wall portion which extends from a bottom portion in such a way that a shorter side of the rectangular wall portion is in contact with the lower end (the end on the opposite side to an ejection direction of the sheet) of the bottom portion when the package is spread out. When the rectangular wall portion is folded, the wall portion faces the bottom portion on which stacked sheets are to be placed and covers an upper face of the stacked sheets. 
     However, there has been a problem with the conventional sheet package that, if the size of sheets stored in the sheet package is enlarged, the length in the longitudinal direction of the package member is increased, and thus, a sheet material from which the package member is to be cut out is enlarged. As a result, the amount of sheet material to be cut off to be wasted is also increased. Thus, it may be possible to connect the rectangular wall portion that covers the upper face of the stacked sheets to the side end of the bottom portion (the direction perpendicular to the sheet ejection direction) rather than to the rear end of the bottom portion and to then fold the rectangular wall portion to cover the upper face of the stacked sheets. 
     However, in a printer in which a sheet package of the above-described structure is set, it is necessary to press the rectangular wall portion of the sheet package by a pressing member provided in the printer in order to press stored sheets against a sheet-feeding roller. Thus, when the rectangular wall portion and the bottom portion are connected via a side end as described above, a problem has arisen that movement of the rectangular wall portion is restricted, and that in consequence the degree of pressing force required for pressing the sheet against the sheet-feeding roller has not been adequate. 
     SUMMARY 
     The present invention has been achieved to solve the above-described problems, and an object of the invention is to provide a sheet package having a structure with which sheets stored in the sheet package can be pressed against a sheet-feeding roller with an adequate degree of pressing force. 
     The present invention provides a sheet package that can be set in a printer for supplying the printer with sheets as print media and that includes a stack of sheets and a package member covering an exterior of the stack of sheets, wherein the package member includes a rectangular first portion covering a part of one face of the stack of sheets in a stacking direction, a second portion covering the other face of the stack of sheets on the other side in the stacking direction and that facing the first portion, a third portion connecting with the second portion via one of a pair of side ends of the first portion and covering a side face of the stack of sheets, and a cut-in portion formed on a boundary between the first portion and the third portion or on a boundary between the second portion and the third portion in a predetermined length from an end on a side that is pressed by a pressing member of the printer in order to press an exposed portion of the stack of sheets exposed from the package member against a sheet-feed roller of the printer when the sheet package is set in the printer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the disclosure will be described in detail below with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a printer; 
         FIG. 2  is a sectional view taken along a line I-I in  FIG. 1 ; 
         FIG. 3  is a diagram showing a sheet package set in a sheet storage portion; 
         FIG. 4  is an enlarged sectional view showing details of a sheet separation portion and a printer mechanism portion; 
         FIG. 5  is a perspective view of the sheet package according to a first embodiment; 
         FIG. 6  is a perspective view of the sheet package when a lid portion is opened; 
         FIG. 7  is a bottom view of the sheet package when the lid portion is opened; 
         FIG. 8  is a developed view of the sheet package showing an outer surface; 
         FIG. 9  is a perspective developed view of the sheet package showing an inner surface; 
         FIGS. 10 through 14  are perspective views showing a process of manufacturing the sheet package; 
         FIGS. 15 and 16  are perspective views showing a procedure for opening a the sheet package upon use; 
         FIG. 17  is a sectional view showing a procedure for setting the sheet package in a printer; 
         FIG. 18  is a developed view of a package member of the sheet package according to a second embodiment as seen from the exterior; 
         FIG. 19  is a developed view of a package member of the sheet package according to a third embodiment as seen from the exterior; and 
         FIG. 20  is a developed view of a package member  8  of the sheet package according to a fourth embodiment as seen from the exterior. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     First, a structure of a printer  1  loaded with a sheet package  9  according to a first embodiment of the present disclosure will be described with reference to  FIGS. 1-4 . As shown in  FIG. 1 , the printer  1  has a flat rectangular parallelepiped configuration which is rectangular in its plan view (slightly larger than A6 size) and which has a thickness of about 2 cm. A body case  2  of the printer  1  includes a frame  3 , a lower cover  4  which covers the bottom of the frame  3 , an upper cover  5  which covers a part of the top of the frame  3 , and a lid  10  which can be opened and closed. The frame  3  and the lower cover  4  both have a rectangular shape in a plan view. 
     As shown in  FIGS. 2 and 3 , a printer mechanism portion  14  is disposed in the interior of an end portion (upper end portion in  FIGS. 2 and 3 ) of the printer  1 . The top of the printer mechanism portion  14  is covered with the upper cover  5  which has a rectangular shape in its plan view. The printer mechanism portion  14  includes a thermal head  15 , a platen roller  16  and a sheet guide  17 . A sheet storage portion  6  is formed in the upper portion of the frame  3  which is not covered with the upper cover  5 . The top of the sheet storage portion  6  is covered with a lid  10 , which is rectangular in its plan view, and this lid  10  can be opened and closed as shown in  FIG. 2 . 
     The sheet storage portion  6  can store a sheet package  9  which contains a plurality of heat-sensitive sheets  7  such as cut sheets of A6 or A7 size inside its package member  8  as shown in  FIG. 3 . Further, the body case  2  is provided with a lock mechanism (not shown) which allows the lid  10  to be closed and locked as shown in  FIG. 3 , with the sheet package  9  set in the sheet storage portion  6 . 
     As shown in  FIG. 4 , a sheet separation portion  11  is provided next to one end of the sheet storage portion  6 , the one end being close to the printer mechanism portion  14 . The sheet separation portion  11  includes a pickup roller  12  and a separation block  13 . In addition, on an inner surface of the lid  10  facing the sheet storage portion  6 , a pressure plate  18  is supported rotatably. A coil-like pressure spring  19  is interposed between the pressure plate  18  and the lid  10  and constantly presses the pressure plate  18  in a downward direction (direction towards the pickup roller  12 ). 
     The sheet package  9  is loaded in the sheet storage portion  6  in such a way that the lower surface of a lowermost sheet of the stacked sheets  7  is partially exposed from the package member  8 . The sheets  7  are stacked in the package member  8  with their print side facing downwards. Then, when the lid  10  is closed and locked, the pressure plate  18 , which is pressed downwards by the pressure spring  19 , presses the exposed portion of the sheet  7  (lowermost sheet) against the pickup roller  12  in such a way that the lower surface of the sheet  7  makes contact with the pickup roller  12 . 
     As shown in  FIG. 4 , the separation block  13  is provided in the vicinity of and facing the pickup roller  12 . The separation block  13  has a separation guide surface  131  that is tilted with respect to the sheet-feeding direction of the pickup roller  12 . In the sheet separation portion  11  of this structure, when the pickup roller  12  is rotated, a frictional carrying force is applied to the lowermost sheet of the stacked sheets  7  which is in contact with the pickup roller  12 . Then, only one of the sheets  7  that is located at the bottom of the stack is separated and fed by the frictional carrying force coupled with separating action of the separation guide face  131  of the separation block  13 . 
     Next, the printer mechanism portion  14  will be described. As shown in  FIG. 4 , the platen roller  16  is provided across the separation block  13  from the pickup roller  12 . The platen roller  16  can be rotated by a motor (not shown). The sheet guide  17  is placed in the vicinity of an exterior peripheral surface of the platen roller  16 . The sheet guide  17  has a concavely curved sliding surface  171  formed along the exterior peripheral surface of the cylindrical platen roller  16 . Accordingly, the sheet guide  17  has a laterally-directed U-shaped section. A pressure coil spring  20  is provided between the sheet guide  17  and the body case  2  so as to press the sliding surface  171  towards the exterior peripheral surface of the platen roller  16 . 
     In the printer  1  having such a structure, one of the sheets  7  separated by the aforementioned sheet separation portion  11  is fed by the pickup roller  12 , and passes through a gap between the bottom end of the separation block  13  and a guide plate  21  for guiding the sheet  7  towards the platen roller  16 . Then, the sheet  7  is guided by the guide plate  21  and fed into a gap between the platen roller  16  and the paper guide  17  from the lower side of the platen roller  16 . Further, the sheet  7  is fed by rotational driving of the platen roller  16  through a gap between the exterior peripheral surface of the platen roller  16  and the sliding surface  171  of the sheet guide  171  and inverted in such a way that it forms a laterally-directed U-shape on the way and then, reaches the top of the platen roller  16  with its print side facing upwards. 
     As shown in  FIG. 4 , the thermal head  15  is placed on the top of the platen roller  16 , and has a heating element portion  151  which is a printing portion. The thermal head  15  is provided rotatably around a rotation shaft  152 , by which the heating element portion  151  can contact and separate from the top of the platen roller  16 . Such a structure helps prevent the thermal head from becoming an obstacle when it is necessary to remove a sheet that has been jammed between the platen roller  16  and the sheet guide  17 . 
     As shown in  FIG. 4 , an end of a spring  22  of a torsion coil spring type is attached to the thermal head  15 . The spring  22  constantly pushes the thermal head  15  so that the heating element portion  151  of the thermal head  15  approaches the top of the platen roller  16 . With this structure, the heating element portion  151  of the thermal head  15  makes contact with the print side of the sheet  7  that is fed by the platen roller  16  with its print side facing upwards as described above, and printing is carried out at the contact position. 
     The thermal head  15  is of a line head type and capable of printing an arbitrary character or image on heat-sensitive type sheets  7  that are fed, on a line by line basis, the line extending in a direction perpendicular to the feed direction of the sheets  7 . A printing width of a single line is set to be substantially equal to the width of the sheet  7  which is a print medium. By employing thermal head  15  as the print head and heat-sensitive sheets as the print media, the use of consumer products such as ink and an ink ribbon becomes unnecessary, and thus a need for a mechanism for supplying ink is eliminated. The printer  1  can thus be designed in a compact configuration. As heat-sensitive sheets, a variety of sheets are available. For example, those of a heat-sensitive coloring type that has a color layer which becomes colored when heated by the thermal head  15 , and those of heat-sensitive perforation type that has a perforation layer which is an over layer on a base layer and becomes perforated by heating, can be used. 
     The separation block  13  has a sheet ejection guide surface  132  which is tilted relative to the sheet-feed direction of the platen roller  16 . With this structure, the sheet  7  that has been through printing by the heating element portion  151  of the thermal head  15  is guided by the sheet ejection guide face  132 , and ejected upwards above the lid  10  from a gap between the upper cover  5  of the body case  2  and the lid  10 . 
     Next, the sheet package  9  according to the first embodiment of the present disclosure, which is to be set in the printer  1 , will be described in detail with reference to  FIGS. 5-12 . As shown in  FIG. 5 , the sheet package  9  is manufactured by folding a rectangular thin package member  8  into a box-like shape. In the sheet package  9 , a plurality of sheets (print media)  7  are stacked and stored. The sheets  7  are cut-sheet type heat-sensitive sheets of a small size, for example, of an A6-A7 size. A user purchases a sheet package  9  sold in a box-like shape as shown in  FIG. 5 , and then, as shown in  FIGS. 6 and 7 , opens the lid  44 , folds it back to the rear side and then inserts an insertion portion  444  of the lid  44  into a third slit  45  formed in a bottom portion  40  that will be described later. In this manner, the sheets  7  stored inside become exposed. A sheet package  9  in this condition is set in the sheet storage portion  6  of the printer  1 . In the following description, an end of the sheet package  9 , that is to be placed on the side of the printer mechanism portion  14  when the sheet package  9  is set in the printer  1 , is referred to as a front end, an end on the opposite side thereof is referred to as the rear end, and the other two opposing ends are referred to as side ends. 
     Next, the structure of the package member  8  will be described with reference to  FIGS. 8 and 9 . The package member  8  is formed by punching out a flat cardboard material, and has a bottom portion  40 , side wall portions  41 - 43 , a lid portion  44 , a first wrapping portion  50 , a second wrapping portion  60 , and a tongue portion  70 . The bottom portion  40 , which covers one face of the stacked sheets  7  in the stacking direction, is provided in the center of the package member  8 . To one of a pair of side ends of the bottom portion  40 , a rectangular side wall portion  41  is continuously formed, while to the other side end of the bottom portion  40 , another rectangular side wall portion  42  is continuously formed. In addition, to the rear end of the bottom portion  40 , still another rectangular side wall portion  43  is continuously formed. The heights (length in a shorter side direction) of the side wall portions  41 - 43  are all equal, and are greater than the stacking height of the sheets  7  stored in the sheet package  9 . 
     As shown in  FIGS. 8 and 9 , to the front end of the bottom portion  40 , the lid portion  44  is continuously formed. The lid portion  44  has a rectangular lid base portion  441 , a lid side wall portion  442 , a flap portion  443  and an insertion portion  444 . The rectangular lid side wall portion  442  is formed continuously to the lid base portion  441  and has a height (length in the shorter side direction) that is identical to the height of the aforementioned side wall portions  41 - 43 . The flap portion  443  is connected to the lid side wall portion  442  and has a width that is less than that of the lid side wall portion  442 . The insertion portion  444  is further connected to the flap portion  443 , and has a width that is less than that of the flap portion  443  and is provided with a pair of tilted sides. A shape of the bottom portion  40  as combined with the lid base portion  441  is substantially the same as that of the sheet  7 . 
     As shown in  FIGS. 8 and 9 , to the side wall portion  41 , a rectangular first wrapping portion  50  is continuously formed. The first wrapping portion  50  is placed to face the bottom portion  40  and covers the sheets  7  after manufacturing. The first wrapping portion  50  has a first slit  51  in which the insertion portion  44  of the lid portion  44  is to be inserted and a second slit  52  in which an insertion portion  61  of the second wrapping portion  60 , which will be described later, is inserted. A square cutout portion  53  is provided on a side end of the first wrapping portion  50  opposing to the lid base portion  441 . With the use of this cutout portion  53 , the printer  1  detects the presence or absence of the sheet  7 . Specifically, The sheet package  9  is loaded in the sheet storage portion  6  of the printer  1  in the state shown in  FIG. 6 . The printer  1  has a reflection type optical sensor  80  (see  FIGS. 3 and 4 ) at a position facing the cutout portion  53 . Thus, as long as any sheet  7  exists in the sheet package  9 , the reflection type optical sensor detects the reflection of light from the sheet  7 . On the other hand, when the sheet  7  is no longer there, the reflection type optical sensor detects a reflected light from the synthetic resin constituting the pressure plate  18  of the lid  10 . Thus, if the color of the synthetic resin constituting the pressure plate  18  of the lid  10  has a low light reflection factor, the presence or absence of a sheet can be detected easily. 
     As shown in  FIG. 8 , on the outer surface of the package member  8 , along a side end of the bottom portion  40  connecting to the side wall portion  41  and the first wrapping portion  50 , three sensor marks  46  are printed to indicate the kinds and sizes of sheets  7  stored in the sheet package  9 . The sensor marks  46  are read by a reflection type optical sensor provided in the printer  1 , a sensor (not shown) that is different from the reflection type optical sensor  80 . For example, on the assumption that a presence of the sensor mark  46  represents “1”, while an absence thereof represents “0”, eight kinds of sheets  7  can be distinguished by means of these three sensor marks  46 . In the bottom portion  40  a third slit  45  is formed in which the insertion portion  444  of the folded back lid portion  44  can be inserted. Further, a cut-in portion  54  is cut between the side wall portion  41  and the first wrapping portion  50  to a predetermined length from the cutout portion  53  side. The cut-in portion  54  facilitates distortion of the first wrapping portion  50  when the sheet package  9  is loaded in the sheet storage portion  6  and the first wrapping portion  50  is pressed by the pressure plate  18 , and the sheets  7  stored in the sheet package  9  can be pressed against the pickup roller  12  with a sufficient degree of force. Further, when the lowermost sheet  7  that makes direct contact with the pickup roller  12  is fed by driving of the pickup roller  12 , friction generated between the first wrapping portion  50  and the uppermost sheet  7  in contact with the first wrapping portion  50  functions to hold other sheets  7  and prevent them from being fed together. Thus, By facilitating distortion of the first wrapping portion  50 , friction force between the first wrapping portion  50  and the sheet  7  is increased, thereby avoiding feeding multiple sheets at a time but feeding the sheets one by one without fail. 
     As shown in  FIGS. 8 and 9 , to the side wall portion  42 , a second wrapping portion  60  is continuously formed. The second wrapping portion  60  faces the bottom portion  40  and fixes the first wrapping portion  50  covering the sheets  7  after manufacturing. The width of the second wrapping portion  60  is narrower than that of the first wrapping portion  50  and has an insertion portion  61  at a side end. When the sheet package  9  is manufactured, this insertion portion  61  is inserted into the second slit  52  of the first wrapping portion  50  so as to fix the first wrapping  50 . 
     As shown in  FIGS. 8 and 9 , to the side wall portion  43 , a rectangular tongue portion  70  is continuously formed. The tongue portion  70  serves to receive the bottom end of the stacked sheets  7  in the process of manufacturing the sheet package  9 . In  FIGS. 8 and 9 , two-dot chain lines indicate lines subjected to fold line processing in order to facilitate folding of the cardboard material along the fold lines, for convenience of manufacturing. 
     Next, a process of manufacturing the sheet package  9  will be described with reference to  FIGS. 10-14 . First, as shown in  FIG. 10 , the side wall portion  43  of the package member  8  is folded upwards and further, the tongue portion  70  is folded at a right angle from the side wall portion  43  so as to face the bottom portion  40 . Next, as shown in  FIG. 11 , the side wall portion  41  is folded upwards and further, the first wrapping portion  50  is folded at a right angle from the side wall portion  41  so as to be overlapped on the tongue portion  70 . Next, as shown in  FIG. 12 , after the side wall portion  42  has been folded upwards, the second wrapping portion  60  is folded over the first wrapping portion  50  and then, the insertion portion  61  of the second wrapping portion  60  is inserted into the second slit  52  of the first wrapping portion  50 . Then, as shown in  FIG. 13 , the stacked sheets  7  are inserted into the package member  8  in this condition. The sheets  7  may be placed onto the bottom portion  40  of the package member  8  before the tongue portion  70  is folded, and after that, the tongue portion  70  may be folded. 
     Finally, as shown in  FIG. 14 , the lid portion  44  is folded over the first wrapping portion  50  and then, the insertion portion  444  of the lid portion  44  is inserted into the first slit  51  in the first wrapping portion  50  so as to complete the sheet package  9 . The sheet packages  9  are put on sale in this condition. 
     A usage method of the sheet package  9  will next be described with reference to  FIGS. 5 ,  6 ,  7 ,  15 ,  16  and  17 . When the sheet package  9  is used, first, the lid portion  44  of the sheet package  9  in the condition shown in  FIG. 5  is raised as shown in  FIG. 15  and then, as shown in  FIGS. 16 and 6 , folded back to the rear side along the line II-II shown in  FIG. 16 . Then, as shown in  FIG. 7 , the insertion portion  444  of the flap portion  443  is inserted into the third slit  45  of the bottom portion  40  so as to fix the lid portion  44  to the bottom portion  40 . The sheet package  9  in this condition is loaded in the sheet storage portion  6  of the printer  1 , as shown in  FIG. 17 . Then, when the lid  10  is closed, the first wrapping portion  50  of the sheet package  9  is pressed by the pressure plate  18  so that the lowermost sheet of the stacked sheets  7  is pressed against the pickup roller  12 . 
     At this time, the reflection type optical sensor  80  provided on the printer  1  comes to face the cutout portion  53  provided on the first wrapping portion  50  of the sheet package  9  (see  FIGS. 3 and 4 ). Therefore, when any sheet  7  exists in the sheet package  9 , the reflection type optical sensor  80  detects reflection light from the sheet  7 . On the other hand, when the sheets  7  have been used up, the reflection type optical sensor  80  detects reflection light from the synthetic resin constituting the pressure plate  18  of the lid  10 . 
     As described above, in the sheet package  9  of the first embodiment, the first wrapping portion  50  is provided with a cutout portion  53  for detecting a presence or an absence of the sheets  7 . Accordingly, the reflection type optical sensor  80  can immediately detect that the sheets  7  are used up and no sheets are left. Moreover, the first wrapping portion  50  occupying a large area is extended from the side end of the bottom portion  40 . Accordingly, with regards to the size of cardboard material from which the package member is to be cut out, the length in a longitudinal direction is not required to become as large as in the case where the first wrapping portion  50  is extended from the rear end. Further, the amount of cardboard material that needs to be cut off to be wasted can be reduced. 
     Next, the second embodiment of the sheet package  9  will be described with reference to  FIG. 18 . The package member  8  of the second embodiment shown in  FIG. 18  has a substantially identical shape to that of the package member  8  of the first embodiment. Therefore, only different portions will be described. A cut-in portion  541  which is cut out in a V-shape at a predetermined length from the cutout portion  53  is provided at a connecting portion between the side wall portion  41  and the first wrapping portion  50 . In the package member  8  of the first embodiment shown in  FIG. 8 , the cut-in portion  54  is formed by cutting a connecting line between the side wall portion  41  and the first wrapping portion  50  linearly to a predetermined length from the cutout portion  53 . On the other hand, in the package member  8  of the second embodiment, the V-shaped cut-in portion  541  is formed by cutting out a part of the side wall portion  41 . A width of the cut-in portion  541  at an opening end is set to be greater than the thickness of the sheet material (cardboard material) that constitutes the package member  8 . 
     Accordingly, when the sheet package  9  of the second embodiment is loaded in the sheet storage portion  6  and the first wrapping portion  50  is pressed by the pressing plate  18 , distortion (movement) of the first wrapping portion  50  can be facilitated. In addition, the V-shaped cut-in portion  541  is formed by cutting out a part of the side wall portion  41 , and the width of the cut-in portion  541  at the opening end is set to be greater than the thickness of the sheet material (cardboard material) that constitutes the package member  8 , thereby preventing the first wrapping portion  50  from hitting the side wall portion  41 . Consequently, smooth movement of the first wrapping portion  50  can be ensured. Thus, the pressing of the sheets  7  stored in the sheet package  9  against the pickup roller  12  can be achieved with an adequate degree of force. As a result, the individual sheets  7  can be fed on by one without fail, and feeding of plural sheets at one and the same time can be prevented as in the first embodiment of the sheet package  9 . 
     Next, a third embodiment of the sheet package  9  will be described with reference to  FIG. 19 . As shown in  FIG. 19 , the package member  8  of the third embodiment has a substantially identical shape to that of the package member  8  of the first or second embodiment. Therefore, only different portions will be described. In the package member  8  of the third embodiment, a V-shaped cut-in portion  542  is provided at a connecting portion between the side wall portion  41  and the first wrapping portion  50 , by cutting out that portion to a predetermined length from the cutout portion  53 . In the package member  8  of the third embodiment, a V-shaped cut-in portion  542  is formed by cutting out a part of the first wrapping portion  50 . Moreover, the width of the cut-in portion  542  at an opening end is set to be greater than the thickness of the sheet material (cardboard material) that constitutes the package member  8 . 
     Thus, in the sheet package  9  of the third embodiment, when the sheet package  9  is loaded on the sheet storage portion  6 , and then the first wrapping portion  50  is pressed by the pressing plate  18 , distortion (movement) of the first wrapping portion  50  can be facilitated. Further, the V-shaped cut-in portion  542  is formed by cutting out apart of the first wrapping portion  50 , and the width of the cut-in portion at the opening end is set larger than the thickness of the sheet material (cardboard material) that constitutes the package member  8 , thereby preventing the cut-in portion  542  of the first wrapping portion  50  from hitting the side wall portion  41 . As a result, smooth movement of the first wrapping portion  50  can be achieved. Thus, the pressing of the sheets  7  stored in the sheet package  9  against the pickup roller  12  can be achieved with an adequate degree of force. Consequently, the individual sheets  7  can be fed one by one without fail and feeding of plural sheets at one and the same time can be prevented as in the first embodiment of the sheet package  9 . 
     Next, a fourth embodiment of the sheet package  9  will be described with reference to  FIG. 20 . As shown in  FIG. 20 , the package member  8  of the fourth embodiment has a substantially identical shape to that of the package member  8  of any of the first through third embodiments. Therefore, only different portions will be described. In the package member  8  of the fourth embodiment, a V-shaped cut-in portion  543  is provided at a connecting portion between the side wall portion  41  and the first wrapping portion  50  extending for a predetermined length from the cutout portion  53 . IN the fourth embodiment, a V-shaped cut-in portion  543  is formed by cutting out a part of the first wrapping portion  50  as well as a part of the side wall portion  41  of the package member  8 . Moreover, the width of the cut-in portion  543  at the opening end is set so as to be greater than the thickness of the sheet material (cardboard material) that constitutes the package member  8 . 
     Thus, in the sheet package  9  of this fourth embodiment, when the sheet package  9  is loaded in the sheet storage portion  6  and then, the first wrapping portion  50  is pressed by the pressure plate  18 , distortion (movement) of the first wrapping portion  50  can be facilitated. Further, a cut-in portion  543  is formed by cutting out both a part of the first wrapping portion  50  and a part of the side wall portion  41  in a V-shape and the width of the cut-in portion  543  at the opening end is set so as to be greater than the thickness of the sheet material (cardboard material) that constitutes the package member  8 , thereby preventing the first wrapping portion  50  from hitting the side wall portion  41 . As a result, smooth movement of the first wrapping portion  50  can be achieved. Thus, the pressing of the sheets  7  stored in the sheet package  9  against the pickup roller  12  can be achieved with an adequate degree of force. Consequently, the individual sheets  7  can be fed one by one without fail and feeding of plural sheets at one and the same time can be prevented as in the first embodiment of the sheet package  9 . 
     The present invention is not restricted to the above-described embodiments but can be modified in various ways. For example, the cutout portion  53  need not be limited to a cutout but may also be a hole made in the first wrapping portion  50 . In other words, anything can be used as long as it is capable of transmitting light emitted by the reflection type optical sensor  80 . Further, a cutout portion  54  may be formed in the connecting portion between the bottom portion  40  and the side wall portion  41 . In this case, the V-shaped cutout may be formed at the side wall portion  41 , either at the bottom portion  40  or at both the side wall portion  41  and the bottom portion  40 . A narrow cutout shape of a predetermined width may also be used instead of the V-shape.