Abstract:
A paper-sheet counting machine ( 10 ) includes: a recognition and counting unit ( 24 ) configured to count paper sheets; a stacking unit ( 26 ) configured to stack therein the paper sheets that have been counted by the recognition and counting unit ( 24 ), an opening being provided in a front face of the stacking unit ( 26 ); a rotary guide unit ( 28 ) provided to the stacking unit ( 26 ) and configured to allow the paper sheets that have been counted by the recognition and counting unit ( 24 ) to be stacked in the stacking unit ( 26 ); a shutter ( 40 ) configured to close the opening provided in the front face of the stacking unit ( 26 ); a shutter drive unit ( 50 ) configured to drive the shutter ( 40 ) to open and close the opening provided in the front face of the stacking unit ( 26 ); and a control unit ( 70 ) configured to control the shutter drive unit ( 50 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/568,604 filed on Dec. 12, 2014, which was a continuation of U.S. patent application Ser. No. 13/202,447 filed on Aug. 19, 2011 (now Abandoned), which was based upon and claimed the benefit of priority from the prior PCT/JP2009/052901 filed on Feb. 19, 2009, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a paper-sheet counting machine adapted for counting paper sheets, such as banknotes, checks and the like. 
       BACKGROUND ART 
       [0003]    In the past, various types of machines have been known as the paper-sheet counting machine adapted for counting the paper sheets, such as the banknotes, checks and the like. For instance, a banknote counting machine disclosed in JP2600100Y2 is provided for setting a plurality of banknotes in a stacked condition on a placing unit (e.g., a hopper), then feeding and inserting each banknote located at the lowest position of the banknotes into a space between a pair of gate units, one by one, by using a feeding unit, such as a feed roller or the like, provided at a bottom part of the placing unit, thereby separating such banknotes, one by one, and feeding each separated banknote downward, via a passage, and further feeding it into a space between two vanes of a stacking wheel located in the middle of the passage. Thereafter, each banknote received between the two vanes is thrown off therefrom, downward onto a stacking unit, while being turned round with rotation of the stacking wheel, and then arranged in the stacking unit. Further, in the banknote counting machine disclosed in JP2600100Y2, a sensor is provided for counting the number of the banknotes passing through this sensor, before such banknotes reach the stacking wheel. 
         [0004]    Further, in JP3537697B and JP3741893B, a banknote processing machine provided for recognizing each banknote and then sorting the recognized banknote, based on each recognition result thereof, is disclosed. In such a banknote processing machine, a plurality of stacking units (or stackers) are provided for respectively receiving the banknotes that have been respectively sorted for each corresponding denomination of money and then fed to the stacking units. In this case, a shutter is provided to each stacker. This shutter serves to selectively close an opening of each stacking unit, in order to prevent access of an operator to the stacking unit. 
       DISCLOSURE OF THE INVENTION 
       [0005]    However, in the conventional banknote counting machine as disclosed in the above JP2600100Y2, each banknote is stacked, with the rotation of the stacking wheel, while falling down forward from the back. Therefore, dust accumulated on the transport path and/or dust attached to each banknote tends to be blown out toward the operator. In addition, in this banknote counting machine, the sound generated in the interior of the machine during its operation tends to leak to the outside, thus making a considerable noise. 
         [0006]    Further, in the above JP3537697B and JP3741893B, the shutter is provided to each stacking unit in the banknote processing machine. However, in this banknote processing machine, the opening is provided at an upper part of each stacking unit, and the shutter is designed for opening and closing such an opening provided at the upper part of each stacking unit. Therefore, this shutter is not directly intended for a dustproof application. More specifically, when in an opening position, the shutter provided to each stacking unit serves to allow the banknotes stacked in this stacking unit to be respectively taken out therefrom. Meanwhile, when in a closing position, this shutter serves to prevent any banknote from being taken out from the corresponding stacking unit. Namely, this shutter is intended only for providing the so-called locking function. 
         [0007]    The present invention was made in view of the above problems. Therefore, it is an object of this invention to provide the paper-sheet counting machine that can prevent the dust accumulated in a casing of the machine and/or dust attached to each paper-sheet from being blown out toward the operator, as well as can successfully prevent the sound generated in the interior of the machine from leaking to the outside during the operation of the machine. 
         [0008]    A paper-sheet counting machine of the present invention includes: a counting unit configured to count paper sheets; a stacking unit configured to stack therein the paper sheets that have been counted by the counting unit, an opening being provided in a front face of the stacking unit; a rotary guide unit provided to the stacking unit and configured to allow the paper sheets that have been counted by the counting unit to be stacked in the stacking unit; a shutter configured to close the opening provided in the front face of the stacking unit; a shutter drive unit configured to drive the shutter to open and close the opening provided in the front face of the stacking unit; and a control unit configured to control the shutter drive unit. 
         [0009]    According to the aforementioned paper-sheet counting machine, the opening and closing operation for the opening provided in the front face of the stacking unit can be performed by the shutter driven by the shutter drive unit controlled by the control unit. Therefore, the opening provided in the front face of the stacking unit can be selectively closed by the shutter. Thus, when this shutter closes the opening, the blowing out of the dust accumulated in the casing of the paper-sheet counting machine and/or dust attached to each paper sheet, toward the operator, can be successfully prevented. Further, when the shutter closes the opening in the front face of the stacking unit, the unwanted leakage of the sound generated in the interior of the paper-sheet counting machine to the outside can be effectively prevented during the operation of the machine. 
         [0010]    In the paper-sheet counting machine of the present invention, it is preferred that the rotary guide unit includes a stacking wheel configured to be rotated about a shaft extending in a substantially horizontal direction, the stacking wheel having a plurality of vanes respectively extending from the outer circumferential face of the stacking wheel, outward in a direction reverse to the rotation direction of the rotary guide unit, and the stacking wheel is configured to receive each paper sheet counted by the counting unit, between the vanes thereof, and then feed the paper sheet received between the vanes into the stacking unit. 
         [0011]    In the paper-sheet counting machine of the present invention, it is preferred that the control unit controls the shutter drive unit to drive the shutter to close the opening provided in the front face of the stacking unit, before the counting process for the paper sheets is started by the counting unit. 
         [0012]    Alternatively, the control unit may control the shutter drive unit to drive the shutter to start closing the opening provided in the front face of the stacking unit, at the same time as starting of the counting process for the paper sheets by the counting unit, thereby allowing the paper sheets to be counted, while the opening is closed. 
         [0013]    In the aforementioned paper-sheet counting machine, it is further preferred that the paper-sheet counting machine further includes a placing unit configured to place thereon the paper sheets to be respectively counted by the counting unit, for allowing such paper sheets, respectively placed on the placing unit, to be fed, one by one, to the counting unit, and a first paper-sheet detection unit configured to detect whether or not the paper sheets are placed on the placing unit, and when the first paper-sheet detection unit detects that all of the paper sheets respectively placed on the placing unit are fed to the counting unit and thus there is no paper sheet remaining on the placing unit, the control unit controls the shutter drive unit to retreat the shutter from the opening provided in the front face of the stacking unit to open the opening. 
         [0014]    In this case, it is further preferred that interval of time between the time the first paper-sheet detection unit detects that there is no paper sheet remaining on the placing unit and the time the control unit controls the shutter drive unit to retreat the shutter from the opening, is capable of being altered by settings. 
         [0015]    It is further preferred that the counting unit is configured to recognize the paper sheets, and the paper-sheet counting machine further comprises a reject unit configured to receive the paper sheets respectively recognized as reject paper sheets by the counting unit and fed thereto from the counting unit, and a second paper-sheet detection unit configured to detect whether or not the paper sheets are stacked in the reject unit, and when the first paper-sheet detection unit detects that there is no paper sheet remaining on the placing unit and when the second paper-sheet detection unit detects that there is a paper sheet or sheets in the reject unit, the control unit serves to drive the shutter to keep closing the opening provided in the front face of the stacking unit. 
         [0016]    It is further preferred that the control unit serves to selectively perform a batch process mode, in which the counting unit counts paper sheets by the batch number, the batch number being instructed to the control unit, and when the first paper-sheet detection unit detects that there is no paper sheet remaining on the placing unit and when the number of the paper sheets fed to the stacking unit does not reach the batch number, during the process for the paper sheets in the batch process mode performed by the control unit, the control unit serves to drive the shutter to keep closing the opening provided in the front face of the stacking unit. 
         [0017]    In the paper-sheet counting machine of the present invention, it is preferred that the control unit serves to selectively perform a batch process mode, in which the counting unit counts paper sheets by the batch number, the batch number being instructed to the control unit, and when the batch number inputted to the control unit is smaller than a preset number, during the process for the paper sheets in the batch process mode performed by the control unit, the control unit serves to retreat the shutter from the opening provided in the front face of the stacking unit to keep the opening opened. 
         [0018]    In the paper-sheet counting machine of the present invention, it is preferred that the paper-sheet counting machine further comprises a placing unit configured to place thereon the paper sheets to be respectively counted by the counting unit, for allowing such paper sheets, respectively placed on the placing unit, to be fed, one by one, to the counting unit, and a third paper-sheet detection unit provided between the placing unit and the stacking unit and configured to detect each paper sheet when the paper sheet fed to the stacking unit from the placing unit passes through the third paper-sheet detection unit, and the control unit serves to selectively perform a batch process mode, in which the counting unit counts paper sheets by the batch number, the batch number being instructed to the control unit, and when the batch number inputted to the control unit is equal to or greater than the preset number, during the process for the paper sheets in the batch process mode performed by the control unit, the control unit controls the shutter drive unit to drive the shutter to close the opening provided in the front face of the stacking unit, before the counting process for the paper sheets is started by the counting unit, and when the third paper-sheet detection unit detects the last paper sheet of the batch number, the control unit controls the shutter drive unit to retreat the shutter from the opening provided in the front face of the stacking unit to open the opening. 
         [0019]    In this case, it is further preferred that interval of time between the time the third paper-sheet detection unit detects the last paper sheet of the batch number and the time the control unit controls the shutter drive unit to retreat the shutter from the opening, is capable of being altered by settings. 
         [0020]    In the paper-sheet counting machine of the present invention, it is preferred that the paper-sheet counting machine further comprises a placing unit configured to place thereon the paper sheets to be respectively counted by the counting unit, for allowing such paper sheets, respectively placed on the placing unit, to be fed, one by one, to the counting unit, and a third paper-sheet detection unit provided between the placing unit and the stacking unit and configured to detect each paper sheet when the paper sheet fed to the stacking unit from the placing unit passes through the third paper-sheet detection unit, and the control unit controls the shutter drive unit to drive the shutter to close the opening provided in the front face of the stacking unit, before the counting process for the paper sheets is started by the counting unit, and when the third paper-sheet detection unit detects a certain paper sheet, with which the stacking unit will be full up upon receiving thereof, the control unit controls the shutter drive unit to retreat the shutter from the opening provided in the front face of the stacking unit to open the opening. 
         [0021]    In this case, it is further preferred that interval of time between the time the third paper-sheet detection unit detects the paper sheet, with which the stacking unit will be full up upon receiving thereof, and the time the control unit controls the shutter drive unit to retreat the shutter from the opening, is capable of being altered by settings. 
         [0022]    It is further preferred that the third paper-sheet detection unit is provided in such a position that interval of time between the time the paper sheet is detected by the third paper-sheet detection unit and the time this paper sheet is fed to the stacking unit is substantially matched with the time required for the shutter to be moved from the position for closing the opening provided in the front face of the stacking unit to the position for opening the same opening. 
         [0023]    In the paper-sheet counting machine of the present invention, it is preferred that the control unit performs selectively either one of a with-shutter-operation mode, in which the control unit controls the shutter drive unit to drive the shutter to open and close the opening provided in the front face of the stacking unit, and a without-shutter-operation mode, in which the shutter drive unit is not controlled by the control unit, and thus the opening and closing operation for the opening provided in the front face of the stacking unit is not performed by the shutter. 
         [0024]    In the paper-sheet counting machine of the present invention, it is preferred that the shutter is configured to be retreated from the opening provided in the front face of the stacking unit, by hand, even during the counting process for the paper sheets by the counting unit. 
         [0025]    In the paper-sheet counting machine of the present invention, it is preferred that the shutter is composed of a transparent material. 
         [0026]    In the paper-sheet counting machine of the present invention, it is preferred that the shutter is capable of being reciprocated, about a shaft, between a closing position for closing the opening provided in the front face of the stacking unit and an opening position retreated from the opening to open the opening, the opening position being located below the rotary guide unit. 
         [0027]    In the paper-sheet counting machine of the present invention, it is preferred that an elastic member is provided to the shutter, and a cam configured to be engaged with the shutter is provided to the shutter drive unit, and the shutter is biased toward the closing position for closing the opening provided in the front face of the stacking unit, by contraction force of the elastic member, and is adapted to be retreated from the opening, toward the opening position for opening the opening, by the cam provided to the shutter drive unit. 
         [0028]    Alternatively, a gear and a torque limiter may be respectively provided between the shutter and the shutter drive unit, and the driving force applied from the shutter drive unit is transmitted to the shutter, via the gear and torque limiter, and when force greater than a preset torque is applied to the torque limiter, the torque limiter may serve to block the driving force transmitted from the shutter drive unit to the shutter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a drawing for schematically illustrating the internal construction of a paper-sheet counting machine related to one embodiment of the present invention, when a shutter closes an opening provided in the front face of a stacking unit. 
           [0030]      FIG. 2  is a drawing for schematically illustrating the internal construction of the paper-sheet counting machine shown in  FIG. 1 , when the shutter is retreated from the opening provided in the front face of the stacking unit to open the opening. 
           [0031]      FIG. 3  is a drawing for illustrating details of the construction of the shutter, a shutter support unit for supporting the shutter, a shutter drive unit and the like, respectively provided in the paper-sheet counting machine shown in  FIG. 1  and the like, when the shutter closes the opening provided in the front face of the stacking unit. 
           [0032]      FIG. 4  is another drawing for illustrating the details of the construction of the shutter, shutter support unit for supporting the shutter, shutter drive unit and the like, respectively provided in the paper-sheet counting machine shown in  FIG. 1  and the like, when the shutter is retreated from the opening provided in the front face of the stacking unit to open the opening. 
           [0033]      FIG. 5  is a block diagram for illustrating a control system of the paper-sheet counting machine shown in  FIG. 1  and the like. 
           [0034]      FIG. 6  is a flow chart showing a series of operations, respectively performed by the paper-sheet counting machine shown in  FIG. 1  and the like. 
           [0035]      FIG. 7  is another flow chart further showing the series of operations, respectively performed by the paper-sheet counting machine shown in  FIG. 1  and the like. 
           [0036]      FIG. 8  is still another flow chart further showing the series of operations, respectively performed by the paper-sheet counting machine shown in  FIG. 1  and the like. 
           [0037]      FIG. 9  is a side view for illustrating the construction of the shutter, shutter support unit for supporting the shutter, shutter drive unit, a plurality of gears, a torque limiter and the like, respectively provided in the paper-sheet counting machine related to one variation of the present invention. 
           [0038]      FIG. 10  is a top view for illustrating the shutter, shutter support unit for supporting the shutter, shutter drive unit, plurality of gears, torque limiter and the like, respectively shown in  FIG. 9 , when such units or parts are respectively seen from above. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    Hereinafter, one embodiment of the present invention will be described, with reference to the drawings. Of these drawings,  FIGS. 1 through 8  are respectively provided for illustrating the paper-sheet counting machine related to the embodiment. More specifically,  FIGS. 1 and 2  are respectively provided for schematically illustrating the internal construction of the paper-sheet counting machine related to the embodiment.  FIGS. 3 and 4  are respectively provided for illustrating the details of the construction of the shutter, shutter support unit for supporting the shutter, shutter drive unit and the like, respectively provided in the paper-sheet counting machine shown in  FIG. 1  and the like. The block diagram of  FIG. 5  is provided for illustrating one exemplary control system of the paper-sheet counting machine shown in  FIG. 1  and the like. Each flow chart of  FIGS. 6 through 8  illustrates the series of operations, respectively performed by the paper-sheet counting machine shown in  FIG. 1  and the like. It is noted that the paper-sheet counting machine related to this embodiment is intended for counting the number of the paper sheets, such as the banknotes, checks and the like. 
         [0040]    As illustrated in  FIGS. 1 and 2 , a paper-sheet counting machine  10  includes a casing  12  and a placing unit  14  adapted for placing thereon a plurality of paper sheets P to be respectively counted, in a stacked condition. Further, this paper-sheet counting machine  10  includes a feeding unit  16  adapted for feeding each paper sheet P located at the lowermost layer of the paper sheets P placed on the placing unit  14  in the stacked condition, one by one, into the casing  12 , and a transport unit  22  adapted for transporting the paper sheets P, respectively fed into the casing  12  by the feeding unit  16 , one by one. In  FIGS. 1 and 2 , the right side face of the casing  12  is depicted as the front face thereof, while the left side face of the casing  12  shows the back face thereof. In addition, a recognition and counting unit  24  adapted for recognizing and counting the paper sheets P respectively fed into the casing  12  from the placing unit  14  is provided to the transport unit  22 . For instance, the recognition and counting unit  24  is composed of a line sensor. 
         [0041]    The feeding unit  16  includes a kicker roller  16   a  provided to be in contact with the surface of one paper sheet P located at the lowermost layer of the paper sheets P placed on the placing unit  14  in the stacked condition, and a feed roller  16   b  located on the downstream side, in the feeding direction of the paper sheets P, relative to the kicker roller  16   a  and adapted for feeding the paper sheets P, respectively kicked out by the kicker roller  16   a,  into the casing  12 . Further, a gate roller (or reverse rotation roller)  16   c  is provided to be opposed to the feed roller  16   b,  with a gate part provided between the feed roller  16   b  and the gate roller  16   c.  Thus, each paper sheet P kicked out by the kicker roller  16   a  is passed through the gate part and then fed out, one by one, toward the transport unit  22  in the casing  12 . 
         [0042]    The transport unit  22  is bifurcated into two transport paths at a point located on the downstream side relative to the recognition and counting unit  24 , and one of the two bifurcated transport paths is connected with a stacking unit  26 , while the other transport path is connected with a reject unit  30 . To the stacking unit  26 , each paper sheet P that has been recognized as a normal paper sheet by the recognition and counting unit  24  is fed. An opening is provided in the front face of the stacking unit  26  (i.e., the face of the stacking unit  26  depicted on the right side in  FIGS. 1 and 2 ), such that the operator can take out the paper sheets P respectively stacked in the stacking unit  26 , via this opening. 
         [0043]    Meanwhile, each paper sheet that is not recognized as the normal paper sheet by the recognition and counting unit  24  and each paper sheet that cannot be recognized by the recognition and counting unit  24  are respectively fed to a reject unit  30 , as reject paper sheets P′, by the transport unit  22 . Similarly, one opening is provided in the front face of the reject unit  30 , such that the operator can take out the reject paper sheets P′ respectively stacked in the reject unit  30 , via this opening. 
         [0044]    As shown in  FIGS. 1 and 2 , a diverter  32  is provided at the same point where the transport unit  22  is bifurcated into the two transport paths. Due to this diverter  32 , each paper sheet that has been fed from the upstream side of the diverter  32  can be selectively fed to either one of the two bifurcated transport paths. 
         [0045]    A stacking wheel  28  is provided on the back face side (i.e., in a position located on the left side shown in  FIGS. 1 and 2 ) of the stacking unit  26  in the casing  12 . This stacking wheel  28  is configured to be rotated in a clockwise direction in  FIG. 1  and the like (i.e., the direction indicated by an arrow depicted in  FIGS. 1 and 2 ) about a shaft extending in a substantially horizontal direction orthogonal to the sheet of  FIG. 1  and the like. The rotational operation of the stacking wheel  28  is performed by a stacking-wheel drive unit  29  (not shown in  FIGS. 1 and 2 ) that will be described later. In this stacking wheel  28 , a plurality of vanes  28   a  are provided to extend outward, from an outer circumferential face of the wheel  28 , in a direction reverse to the rotation direction of the wheel  28  (i.e., the anticlockwise direction in  FIG. 1  and the like). More specifically, such vanes  28   a  are provided to the outer circumferential face of the stacking wheel  28 , at an equal interval, as shown in  FIG. 1  and the like. 
         [0046]    The stacking wheel  28  is configured to be constantly rotated in the clockwise direction in  FIG. 1  and the like, by the stacking-wheel drive unit  29 , during the operation of the paper-sheet counting machine  10 , thereby to receive the paper sheets P, respectively fed from the transport unit  22 , one by one. Then, the stacking wheel  28  receives each paper sheet P fed from the transport unit  22 , between the two vanes  28   a  thereof, and then feeds the paper sheet P received between the two vanes  28   a  into the stacking unit  26 . In this way, the paper sheets P can be fed to the stacking unit  26 , one by one, from the stacking wheel  28 , as such the plurality of paper sheets P can be stacked in the stacking unit  26 . 
         [0047]    In the paper-sheet counting machine  10  of this embodiment, a shutter  40  is provided to close the opening provided in the front face of the stacking unit  26 . Thus, the opening in the front face of the stacking unit  26  can be selectively closed by the shutter  40 . By a shutter drive unit  50  (not shown in  FIGS. 1 and 2 ) that will be described later and is composed of, for example, a motor, the shutter  40  is moved, between the closing position, as depicted in  FIG. 1 , in which the opening in the front face of the stacking unit  26  is closed, and the opening position, as depicted in  FIG. 2 , in which the shutter  40  is retreated from the opening in the front face of the stacking unit  26  to open the opening. Namely, when the shutter  40  is located in the closing position as depicted in  FIG. 1 , the opening in the front face of the stacking unit  26  is closed, thus preventing the operator from accessing the paper sheets P respectively stacked in the stacking unit  26 . Meanwhile, when the shutter  40  is located in the opening position as depicted in  FIG. 2 , this shutter  40  is retreated from the opening in the front face of the stacking unit  26 , and thus the opening is opened, thereby allowing the operator to access the paper sheets P respectively stacked in the stacking unit  26 . 
         [0048]    Now, the reason why the shutter  40  is provided will be described below. In the paper-sheet counting machine  10  including the stacking wheel  28  provided to the stacking unit  26 , each paper sheet P is stacked in the stacking unit  26 , while falling down forward from the back (or rightward from the left as shown in  FIG. 1  and the like). Therefore, there is a risk that the dust accumulated in the stacking unit  26  and the like and/or dust attached to each paper sheet P may be blown out toward the operator, via the opening in the front face of the stacking unit  26 . However, when the shutter  40  is moved to the closing position, as depicted in  FIG. 1 , to close the opening in the front face of the stacking unit  26 , this shutter  40  can serve to suppress the blowing out of the dust toward the operator with rotation of the stacking wheel  28 . Further, when the shutter  40  is located in the closing position to close the opening in the front face of the stacking unit  26 , the unwanted leakage of the sound generated in the paper-sheet counting machine  10 , to the outside, can be prevented during the operation of the machine  10 . 
         [0049]    The shutter  40  may be composed of a transparent material, such as a plastic material or the like. In this case, even in the case the shutter  40  is located in the closing position in which the opening in the front face of the stacking unit  26  is closed as depicted in  FIG. 1 , the operator can confirm, with eyes, the stacked condition of the paper sheets P in the stacking unit  26 , via the shutter  40  formed of a proper transparent material. 
         [0050]    Next, the operation of the shutter  40  driven by the shutter drive unit  50  will be described in more detail, with reference to  FIGS. 3 and 4 .  FIGS. 3 and 4  are respectively provided for illustrating the details of the construction of the shutter  40 , shutter support unit  42  for supporting the shutter  40 , shutter drive unit  50  and the like, respectively provided in the paper-sheet counting machine  10  shown in  FIG. 1  and the like. More specifically,  FIG. 3  is provided for illustrating one operational state corresponding to  FIG. 1 , in which the shutter  40  closes the opening provided in the front face of the stacking unit  26 . Meanwhile,  FIG. 4  is provide for illustrating another operational state corresponding to  FIG. 2 , in which the shutter  40  is retreated from the opening provided in the front face of the stacking unit  26  to open the opening. 
         [0051]    As shown in  FIG. 3  and the like, the shutter  40  is supported by the shutter support unit  42 , and a substantially rectangular plate member  44  is attached to the shutter support unit  42 . A shaft  44   a  is provided to a central part of the plate member  44 , such that the plate member  44  is reciprocated about this shaft  44   a.  As such, the shutter  40  supported by the shutter support unit  42  is also reciprocated about the shaft  44   a.  Further, a circular linking member  44   b  is attached to one end of the plate member  44  on the opposite side of the shutter  40 , such that this linking member  44   b  can be optionally rotated relative to the plate member  44 . 
         [0052]    Further, an elastic member, more specifically, one end  46   b  of a spring  46 , is attached to the end of the plate member  44  opposite to the end thereof to which the linking member  44   b  is provided. In this case, the other end  46   a  of the spring  46  opposite to the one end  46   b  thereof attached to the plate member  44  is fixed to an inner face of the casing  12 . Namely, the other end  46   a  of the spring  46  is fixed in position, while the position of the one end  46   b  of the spring  46  attached to the end of the plate member  44  is changed, with the reciprocation movement of the plate member  44  about the shaft  44   a.  With such configuration, due to contraction force of the spring  46 , the shutter  40  is constantly biased from the opening position thereof as depicted in  FIG. 4  toward the closing position thereof as depicted in  FIG. 3 . 
         [0053]    Further, a cam  52  is provided to be in contact with the outer circumferential face of the circular linking member  44   b  rotatably provided relative to the plate member  44 . This cam  52  has a rotation shaft  51  attached thereto and located in a point eccentric to the central part of the cam  52 . This rotation shaft  51  is rotated in the anticlockwise direction in  FIG. 3  and the like (as indicated by an arrow), by the shutter drive unit  50  composed of, for example, the motor or the like. Thus, the cam  52  is also rotated in the anticlockwise direction in  FIG. 3  and the like (as indicated by the arrow), about the rotation shaft  51 . With this rotation of the cam  52  about the rotation shaft  51 , the linking member  44   b  that is in contact with an edge portion of the cam  52  is pressed and pushed upward in  FIG. 3  (as indicated by another arrow), from the state shown in  FIG. 3 . Thus, the plate member  44  is rotated in the clockwise direction about the shaft  44   a.  As such, the shutter support unit  42  attached to the plate member  44  is also rotated in the clockwise direction about the shaft  44   a  from the state shown in  FIG. 3 , thus allowing the shutter support unit  42  to be moved to the position shown in  FIG. 4  from the position shown in  FIG. 3 . In this way, the shutter  40  is moved to the opening position as depicted in  FIG. 2 , from the closing position as depicted in  FIG. 1 . During this operation, the spring  46  is expanded from the state shown in  FIG. 3  to the state shown in  FIG. 4 . 
         [0054]    However, when the cam  52  is further rotated about the rotation shaft  51 , in the anticlockwise direction in  FIG. 4  (as indicated by an arrow) from the state as shown in  FIG. 4 , the circular linking member  44   b  provided to the plate member  44  is no longer pressed upward in  FIG. 4  by the cam  52 . As such, due to the contraction force of the spring  46 , the plate member  44  is rotated in the anticlockwise direction in  FIG. 4 , about the shaft  44   a,  from the state shown in  FIG. 4 . Thus, the shutter support unit  42  attached to the plate member  44  is also rotated in the anticlockwise direction, about the shaft  44   a,  from the state shown in  FIG. 4 , and hence returned to the position shown in  FIG. 3  from the position shown in  FIG. 4 . In this way, the shutter  40  is returned to the closing position as shown in  FIG. 1 , from the opening position as shown in  FIG. 2 . During this operation, the spring  46  is contracted into the state shown in  FIG. 3 , from the state shown in  FIG. 4 . 
         [0055]    In this way, the shutter  40  is reciprocated about the shaft  44   a  by the shutter drive unit  50 , between the closing position (see  FIGS. 1 and 3 ), in which the opening in the front face of the stacking unit  26  is closed, and the opening position (see  FIGS. 2 and 4 ), in which the shutter  40  is retreated from the opening to open this opening. In the opening position, as shown in  FIG. 2  and the like, the shutter  40  is located below the stacking wheel  28 . Thus, when the shutter  40  is located in the opening position, the dust generated from the stacking wheel  28  and the like can be received by this shutter  40 , thereby preventing such dust being accumulated on an inner bottom face of the casing  12 . 
         [0056]    For instance, the time required for the shutter  40  to be moved from the closing position shown in  FIG. 1  to the opening position shown in  FIG. 2  and the time required for the shutter  40  to be moved from the opening position shown in  FIG. 2  to the closing position shown in  FIG. 1  are set at 0.5 seconds, respectively. 
         [0057]    Further, since the shutter  40  is biased, toward the closing position as depicted in  FIG. 3  from the opening position as depicted in  FIG. 4 , by the contraction force of the spring  46 , this shutter  46  can be moved downward, by hand, from the closing position shown in  FIG. 3 , against the contraction force of the spring  40 . Therefore, the shutter  40  can be retreated, as needed, by hand, from the opening in the front face of the stacking unit  26 , even in a period of time during which the shutter  40  is located in the closing position shown in  FIG. 3  and the paper sheets P are counted by the recognition and counting unit  24 . In this way, the paper sheets P can be taken out from the stacking unit  26 . 
         [0058]    Further, as described above, the spring  46  is provided to the shutter  40 , and the cam  52  is provided to the shutter drive unit  50 , while being engaged with the linking member  44   b  of the plate member  44 . In addition, the shutter  40  can be biased toward the closing position (as shown in  FIG. 3 ) in which the opening in the front face of the stacking unit  26  is closed, by the contraction force of the spring  46 , as well as can be retreated from the opening in the front face of the stacking unit  26  toward the opening position (as shown in  FIG. 4 ) to open the opening, by the cam  52  provided to the shutter drive unit  50 . Therefore, this configuration can successfully prevent the finger or the like of the operator from being accidentally nipped and injured by the shutter  40 , during the period of time in which the shutter  40  is moved from the opening position shown in  FIG. 2  to the closing position shown in  FIG. 1 . This is because, the force used for pressing and moving the shutter  40  toward the closing position is not the driving force exerted from the shutter drive unit  50 , but the contraction force of the spring  46 . 
         [0059]    As shown in  FIGS. 3 and 4 , a shutter-closing detection sensor  54   a  and a shutter-opening detection sensor  54   b  are respectively fixed in position in the vicinity of the cam  52 . Each of the shutter-closing detection sensor  54   a  and shutter-opening detection sensor  54   b  is composed of an optical sensor. Further, a detection target member  53  to be detected by each of the shutter-opening detection sensor  54   a  and shutter-opening detection sensor  54   b  is provided to one side face of the cam  52 . In this case, as shown in  FIG. 3 , when the shutter-closing detection sensor  54   a  detects the detection target member  53 , the shutter  40  is detected to be in the closing position. Meanwhile, when the cam  52  is rotated in the anticlockwise direction about the rotation shaft  51 , from the state shown in  FIG. 3  to the state shown in  FIG. 4 , the shutter-opening detection sensor  54   b  detects the detection target member  53 . As a result, the shutter  40  is detected to be in the opening position. 
         [0060]    In addition, as shown in  FIG. 1  and the like, various sensors are provided to the paper-sheet counting machine  10 . Specifically, to the placing unit  14 , a placing-unit-residue detection sensor (or first paper-sheet detection unit)  60  is provided for detecting whether or not there are some paper sheets P remaining on the placing unit  14 . Further, to the reject unit  30 , a reject-unit paper-sheet detection sensor (or second paper-sheet detection unit)  62  is provided for detecting whether or not there are some reject paper sheets P′ remaining in the reject unit  30 . Additionally, to the transport unit  22  located on the upstream side relative to the recognition and counting unit  24 , a paper-sheet tracking detection sensor (or third paper-sheet detection unit)  64  is provided for detecting each paper sheet P when the paper sheet P transported by the transport unit  22  passes through this paper-sheet tracking detection sensor  64 . In  FIGS. 1 and 2 , while the paper-sheet tracking detection sensor  64  is located on the upstream side relative to the recognition and counting unit  24  in the transport unit  22 , this paper-sheet tracking detection sensor  64  may be located on the downstream side relative to the recognition and counting unit  24 . 
         [0061]    Now, the position in which the paper-sheet tracking detection sensor  64  is located will be described more specifically. Namely, this paper-sheet tracking detection sensor  64  is provided to the transport unit  22 , in such a position that interval of time between the time one paper sheet P is detected by the paper-sheet tracking detection sensor  64  and the time this paper sheet P is fed to the stacking unit  26 , is substantially matched with the time required for the shutter  40  to be moved from the closing position (see  FIG. 1 ) in which the opening in the front face of the stacking unit  26  is closed to the opening position (see  FIG. 2 ) in which the opening is opened (e.g., 0.5 seconds). With such provision of the paper-sheet tracking detection sensor  64  in the position as described above in the transport unit  22 , if the shutter  40  starts to move from its closing position shown in  FIG. 1  when one paper sheet P is detected by the paper-sheet tracking detection sensor  64 , this paper sheet P reaches the stacking unit  26  at the same time the shutter  40  reaches the opening position shown in  FIG. 2 . Thus, the operator can take out each paper sheet P from the stacking unit  26 , immediately after the paper sheet P reaches the stacking unit  26 . 
         [0062]    Additionally, a diversion timing sensor  66  is provided on the upstream side relative to the diverter  32  in the transport unit  22 . The diverter  32  is optionally moved to either one of a first position for feeding each paper sheet P to the stacking unit  26  and a second position for feeding the paper sheet P to the reject unit  30 , at each timing on which the paper sheet P is detected by the diversion timing sensor  66  (e.g., in  FIGS. 1 and 2 , the diverter  32  is shown to be located in the position for feeding the paper sheet P to the stacking unit  26 ). With this configuration, each paper sheet P that has been transported by the transport unit  22  and detected by the diversion timing sensor  66  is selectively fed, by the diverter  32 , to either one of the two transport paths. 
         [0063]    Further, a stacking-unit paper-sheet detection sensor  68  is provided on a downstream-side end of the transport unit  22  extending toward the stacking unit  26 . This stacking-unit paper-sheet detection sensor  68  serves to detect each paper sheet P when the paper sheet P is fed to the stacking wheel  28  from the transport unit  22 . With the provision of this stacking-unit paper-sheet detection sensor  68 , the number of the paper sheets P respectively fed to the stacking unit  26  can be counted. 
         [0064]    As shown in  FIG. 5  and the like, the paper-sheet counting machine  10  includes a control unit  70 . This control unit  70  serves to control each component of the paper-sheet counting machine  10 . More specifically, this control unit  70  is connected with each of the feeding unit  16 , transport unit  22 , recognition and counting unit  24 , stacking-wheel drive unit  29  for driving the stacking wheel  28 , diverter  32  and shutter drive unit  50  for driving the shutter  40 . In this case, the recognition and counting result on each paper sheet P recognized by the recognition and counting unit  24  is sent to the control unit  70 , while the control unit  70  sends a command signal to each of the feeding unit  16 , transport unit  22 , stacking-wheel drive unit  29 , diverter  32 , shutter drive unit  50  and the like, in order to control such components. Further, the control unit  70  is connected with each of the placing-unit-residue detection sensor  60 , reject-unit paper-sheet detection sensor  62 , paper-sheet tracking detection sensor  64 , diversion timing sensor  66  and stacking-unit paper-sheet detection sensor  68 , in order to receive each detection result from such sensors. 
         [0065]    In addition, the control unit  70  is connected with the shutter-closing detection sensor  54   a  and shutter-opening detection sensor  54   b.  Thus, the control unit  70  receives information that the shutter  40  is located in the closing position shown in  FIG. 3  or information that the shutter  40  is located in the opening position shown in  FIG. 4 , from the shutter-closing detection sensor  54   a  or shutter-opening detection sensor  54   b.  Furthermore, the control unit  70  is connected with a display unit  72  and an operation unit  74 . The display unit  72  and operation unit  74  are respectively provided to a front face of the casing  12 . In this case, the condition under which the paper sheets P are handled by the paper-sheet counting machine  10 , more specifically the information on the number or the like of the paper sheets P counted by the recognition and counting unit  24 , is displayed on the display unit  72 . Further, the operator can input various commands to the control unit  70  via the operation unit  74 . 
         [0066]    Next, referring to the flow charts of  FIGS. 6 through 8 , the operation of the paper-sheet counting machine  10  constructed as described above will be discussed. It is noted that the operation of the paper-sheet counting machine  10  is performed by controlling each component of the paper-sheet counting machine  10 , under control of the control unit  70 . 
         [0067]    First of all, the operator places the paper sheets P to be counted, on the placing unit  14 , in the stacked condition. 
         [0068]    In this case, two operational modes, i.e., a with-shutter-operation mode and a without-shutter-operation mode, are provided to the control unit  70 . The with-shutter-operation mode means a mode in which the control unit  70  controls the shutter drive unit  50 , in order to open and close the opening in the front face of the stacking unit  26  by using the shutter  40 . Meanwhile, the without-shutter-operation mode means a mode in which the control unit  70  does not control the shutter drive unit  50  and thus the opening and closing operation for the opening in the front face of the stacking unit  26  is not performed by the shutter  40 . When the paper-sheet counting machine  10  is operated, the operator selects either one of the with-shutter-operation mode and without-shutter-operation mode, via the operation unit  74 . 
         [0069]    In the case the without-shutter-operation mode is selected by the operator, via the operation unit  74 , the paper sheets P placed on the placing unit  14  are counted and the so-counted paper sheets P are fed to the stacking unit  26 , in a state in which the shutter  40  is kept located in the opening position shown in  FIG. 2 , or in a state in which the opening in the front face of the stacking unit  26  is kept opened. 
         [0070]    Meanwhile, in the case the with-shutter-operation mode is selected by the operator, via the operation unit  74 , the operation shown in the flow charts of  FIGS. 6 through 8  is performed. Namely, in an initial state of this operation, the shutter  40  is retreated from the opening in the front face of the stacking unit  26  (i.e., the shutter  40  is located in the opening position shown in  FIG. 2 ), and thus the opening in the front face of the stacking unit  26  is opened (STEP  1  of  FIG. 6 ). 
         [0071]    In this case, the control unit  70  serves to selectively perform a batch process mode, in which the counting unit  24  counts paper sheets P by the batch number, the batch number being instructed to the control unit  70  via the operation unit  74 . Then, as shown in STEP  2  of  FIG. 6 , whether or not the batch process mode is performed is selected by the operator via the operation unit  74 . If the batch process mode is selected to be performed by the operator, the operation, as is shown in the flow charts of  FIGS. 7 and 8  described later, is performed. The operation of the paper-sheet counting machine  10  associated with this batch process mode will be described later. Meanwhile, if the batch process mode is not selected to be performed, the counting process for the paper sheets P, as will be described below, is performed in accordance with the flow chart of  FIG. 6 . 
         [0072]    Namely, before the counting process for the paper sheets P by the recognition and counting unit  24  is started, the control unit  70  controls the shutter drive unit  50  to drive the shutter  40  to close the opening in the front face of the stacking unit  26  (STEP  3  of  FIG. 6 ). More specifically, the shutter drive unit  50  rotates the rotation shaft  51  in the anticlockwise direction in  FIG. 4  (i.e., in the direction indicated by the arrow), from the state shown in  FIG. 4 . As a result, the circular linking member  44   b  provided to the plate member  44  is no longer pressed upward in  FIG. 4  by the cam  52 . Thus, the plate member  44  is rotated, by the contraction force of the spring  46 , in the anticlockwise direction in  FIG. 4 , about the shaft  44   a,  from the state shown in  FIG. 4 . Therefore, the shutter support unit  42  attached to the plate member  44  is also rotated in the anticlockwise direction in  FIG. 4 , about the shaft  44   a,  from the state shown in  FIG. 4 . Eventually, the shutter support unit  42  is moved from the position shown in  FIG. 4  to the position shown in  FIG. 3 . In this way, the shutter  40  is moved from the opening position as shown in  FIG. 2  to the closing position as shown in  FIG. 1 , thus closing the opening in the front face of the stacking unit  26 . 
         [0073]    The timing on which the opening in the front face of the stacking unit  26  is closed by the shutter  40  is set, as the timing before the counting process for the paper sheets P by the recognition and counting unit  24  is started, i.e., the timing before the counting process for the paper sheets P is started or timing substantially the same as the start of the counting process for the paper sheets P. If the opening in the front face of the stacking unit  26  is closed by the shutter  40  at substantially the same timing as the start of the counting process for the paper sheets P, the time required for the entire process for the paper sheets P in the paper-sheet counting machine  10  can be reduced. 
         [0074]    The control unit  70  may control the shutter drive unit  50  to drive the shutter  40  to start closing the opening in the front face of the stacking unit  26 , at the same time as the start of the counting process for the paper sheets P by the recognition and counting unit  24 , thereby to close the opening in the front face of the stacking unit  26 , while counting the paper sheets P. In this case, the opening in the front face of the stacking unit  26  is closed, in a period of time during which the paper sheets P are counted. Therefore, the time required for the entire process for the paper sheets P in the paper-sheet counting machine  10  can be reduced, as compared with the case in which the paper sheets P are counted after the opening in the front face of the stacking unit  26  is closed. 
         [0075]    Thereafter, the paper sheets P, respectively placed in the stacked condition on the placing unit  14 , are fed to the transport unit  22  in the casing  12 , one by one, by the feeding unit  16 , successively, from the paper sheet P located at the lowermost layer, and then transported by the transport unit  22 . At this time, the recognition and counting process for the paper sheets P is performed by the recognition and counting unit  24 . In this case, each paper sheet P recognized, as the normal paper sheet, by the recognition and counting unit  24  is fed to the stacking unit  26  via the diverter  32 . More specifically, the paper sheets P are fed, one by one, from the transport unit  22  to the stacking wheel  28 . Then, the stacking wheel  28  receives each paper sheet P fed from the transport unit  22 , between the two vanes  28   a  thereof. Thereafter, each paper sheet P received between the two vanes  28   a  is fed into the stacking unit  26 . In this way, the paper sheets P can be arranged in the stacking unit  26 , by the stacking wheel  28 . At this time, since the opening in the front face of the stacking unit  26  is closed by the shutter  40 , the operator cannot take out the paper sheets P stacked in the stacking unit  26 . 
         [0076]    Meanwhile, each paper sheet that is not recognized as the normal paper sheet by the recognition and counting unit  24  and each paper sheet that cannot be recognized by the recognition and counting unit  24  are respectively fed, as the reject paper sheets P′, to the reject unit  30 , by the diverter  32 . Since the opening is provided in the front face of the reject unit  30 , the operator can take out the reject paper sheets P′ stacked in the reject unit  30 , via this opening. 
         [0077]    When a maximum number of the reject paper sheets P′ that can be stored in the reject unit  30  is set in advance, and when the number of the reject paper sheets P′ fed to the reject unit  30  reaches this preset maximum number or when the reject unit  30  is full up with the reject paper sheets P′, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  4  of  FIG. 6 ), this condition of the reject unit  30  is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is once stopped. Thereafter, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  5  of  FIG. 6 ), sets again such reject paper sheets P′ on the placing unit  14 , and starts again the counting process for the paper sheet P, via the operation unit  74  (STEP  6  of  FIG. 6 ). In this way, the counting process for the paper sheets P is started again in the paper-sheet counting machine  10 . In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0078]    Further, when a maximum number of the paper sheets P that can be stored in the stacking unit  26  is set in advance, and when the number of the paper sheets P fed to the stacking unit  26  reaches this preset maximum number or when the stacking unit  26  is full up with the paper sheets P, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  7  of  FIG. 6 ), this condition of the stacking unit  26  is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is once stopped. Then, the control unit  70  controls the shutter drive unit  50  to move the shutter  40  to the opening position shown in  FIG. 2  from the closing position shown in  FIG. 1 . As a result, the opening in the front face of the stacking unit  26  is opened (STEP  8  of  FIG. 6 ). Thereafter, the operator takes out the paper sheets P stacked in the stacking unit  26  via the opening in the front face of the stacking unit  26  (STEP  9  of  FIG. 6 ), and then starts again the counting process for the paper sheet P, via the operation unit  74  (STEP  10  of  FIG. 6 ). In this way, the counting process for the paper sheets P in the paper-sheet counting machine  10  is started again. Also in this case, in place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator takes out the paper sheets P form the stacking unit  26 . In this case, before the counting process for the paper sheets P is started again by the recognition and counting unit  24 , the control unit  70  controls the shutter drive unit  50  to drive the shutter  40  to close the opening in the front face of the stacking unit  26  (STEP  3  of  FIG. 6 ). 
         [0079]    In this manner, the counting process for the paper sheets P in the paper-sheet counting machine  10  is continued, until no paper sheet P remains on the placing unit  14 . During this counting process, the placing-unit-residue detection sensor  60  detects whether or not there are some paper sheets P remaining on the placing unit  14  (STEP  11  of  FIG. 6 ). When the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , this detection result is displayed on the display unit  72 . Thereafter, the reject-unit paper-sheet detection sensor  62  detects whether or not there are some reject paper sheets P′ remaining in the reject unit  30  (STEP  12  of  FIG. 6 ). When the reject-unit paper-sheet detection sensor  62  detects that there are some reject paper sheets P′ remaining in the reject unit  30 , this detection result is displayed on the display unit  72 . Thereafter, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  15  of  FIG. 6 ), sets again such paper sheets P′ on the placing unit  14 , and then starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  16  of  FIG. 6 ). In this way, the counting process for the paper sheets P in the paper-sheet counting machine  10  is started again. In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0080]    Meanwhile, when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , and when the reject-unit paper-sheet detection sensor  62  detects that there is no reject paper sheet P′ remaining in the reject unit  30 , the counting process for the paper sheets P in the paper-sheet counting machine  10  is ended (STEP  13  of  FIG. 6 ). Thereafter, the control unit  70  controls the shutter drive unit  50  to move the shutter  40  to the opening position shown in  FIG. 2  from the closing position shown in  FIG. 1 . Thus, the opening in the front face of the stacking unit  26  is opened (STEP  14  of  FIG. 6 ). Then, the operator takes out the paper sheets P stacked in the stacking unit  26 , via the opening in the front face of the stacking unit  26 . In this way, the operation of the paper-sheet counting machine  10 , in the case of not performing the batch process mode, is completed. 
         [0081]    According to the operation of the paper-sheet counting machine  10  as shown in the flow chart of  FIG. 6 , as shown in the operation in the STEP  3  of  FIG. 6 , the control unit  70  controls the shutter drive unit  50  to drive the shutter  40  to close the opening provided in the front face of the stacking unit  26 , before the counting process for the paper sheets P is started by the recognition and counting unit  24 . Therefore, the opening in the front face of the stacking unit  26  is closed by the shutter  40 , during the period of time in which the counting process for the paper sheets P is performed by the recognition and counting unit  24 , thereby preventing the dust accumulated in the casing  12  of the paper-sheet counting machine  10  and/or dust attached to each paper sheet from being blown out toward the operator. 
         [0082]    Further, as shown in the STEP  11  and STEP  13  of  FIG. 6 , when the paper sheets P placed on the placing unit  14  are all fed to the recognition and counting unit  24  and thus the placing-unit-residue detection sensor  60  detects that there is no paper sheet remaining on the placing unit  14 , the control unit  70  controls the shutter drive unit  50  to retreat the shutter  40  from the opening provided in the front face of the stacking unit  26  to open the opening. Alternatively, skipping the operation in the STEP  12  of  FIG. 6 , or the control unit  70  may serve to open the opening in the front face of the stacking unit  26 , once the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , irrespectively of whether or not there are some reject paper sheets P′ remaining in the reject unit  30 . In addition, interval of time between the time the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14  and the time the control unit  70  controls the shutter drive unit  50  to retreat the shutter  40  from the opening in the front face of the stacking unit  26 , may be optionally altered, by the operator, with appropriate settings via the operation unit  74 . In this case, the operator can optionally select the order of priority, between the dustproof and/or soundproofing in the paper-sheet counting machine  10  and the reduction of the time required for handling the paper sheets P. 
         [0083]    Further, as shown in the STEP  11  and STEP  12  of  FIG. 6 , when the reject-unit paper-sheet detection sensor  62  detects that there are some reject paper sheets P′ remaining in the reject unit  30  even though the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , the control unit  70  serves to drive the shutter  40  to keep closing the opening provided in the front face of the stacking unit  26 . This is because, when there are some reject paper sheets P′ remaining in the reject unit  30  even though there is no paper sheet P remaining on the placing unit  14 , it is necessary for the operator to take out such reject paper sheets P′ from the reject unit  30 , and set again the reject paper sheets P′ on the placing unit  14 , and then start again the counting process for the paper sheets P in the paper-sheet counting machine  10 . 
         [0084]    In the operation of the paper-sheet counting machine  10  as shown in the flow chart of  FIG. 6 , as shown in the operation in the STEP  7  of  FIG. 6 , when the paper-sheet tracking detection sensor  64  provided to the transport unit  22  detects a certain paper sheet, with which the stacking unit  26  will be full up upon receiving thereof, the control unit  70  may control the shutter drive unit  50  to retreat the shutter  40  from the opening in the front face of the stacking unit  26  to open the opening. Due to this operation, as compared with the case in which the shutter drive unit  50  starts to move the shutter  40  once the number of the paper sheets P fed to the stacking unit  26  reaches the preset maximum number of the paper sheets P that can be stored in the stacking unit  26  or once the stacking unit  26  is full up with the paper sheets P, the opening in the front face of the stacking unit  26  can be opened more rapidly, thereby to substantially reduce the time required for the entire process for the paper sheets P. It is noted that interval of time between the time the paper-sheet tracking detection sensor  64  detects the paper sheet P, with which the stacking unit  26  will be full up upon receiving thereof, and the time the control unit  70  controls the shutter drive unit  50  to retreat the shutter  40  from the opening in the front face of the stacking unit  26 , may be optionally altered, by the operator, with proper settings via the operation unit  74 . In this case, the operator can optionally select the order of priority, between the dustproof or soundproofing in the paper-sheet counting machine  10  and the reduction of the time required for handling the paper sheets P. 
         [0085]    As described above, the paper-sheet tracking detection sensor  64  is provided in such a position that interval of time between the time one paper sheet P is detected by the paper-sheet tracking detection sensor  64  and the time this paper sheet P is fed to the stacking unit  26 , is substantially matched with the time required for the shutter  40  to be moved from the closing position (see  FIG. 1 ) in which the opening in the front face of the stacking unit  26  is closed to the opening position (see  FIG. 2 ) in which the opening is opened. Therefore, when the paper-sheet tracking detection sensor  64  detects a certain paper sheet, with which the stacking unit  26  will be full up upon receiving this paper sheet P fed thereto, and then this paper sheet P actually reaches the stacking unit  26 , the opening in the front face of the stacking unit  26  is just opened. Thus, the operator can take out a batch of the paper sheets P stacked in the stacking unit  26 , just after the certain paper sheet P reaches the stacking unit  26 . 
         [0086]    Now, referring to the flow charts of  FIGS. 7 and 8 , the operation of the paper-sheet counting machine  10 , in the case the batch process mode is selected by the operator, will be described. 
         [0087]    First, the operator designates the batch number of the paper sheets, via the operation unit  74 . Then, the control unit  70  compares the batch number inputted to the control  70  via the operation unit  74  with a preset number (e.g., ten) of the paper sheets (STEP  21  of  FIG. 7 ). If the batch number inputted to the control unit  70  is equal to or greater than the preset number, the operation, shown in the flow chart of  FIG. 8  described later, is performed. The operation of the paper-sheet counting machine  10  in the batch process mode will be described later. Meanwhile, in the case the batch number inputted to the control unit  70  via the operation unit  74  is smaller than the preset number, the control unit  70  serves to keep the shutter  40  retreated from the opening in the front face of the stacking unit  26 , thereby to keep this opening opened. Thereafter, the counting process for the paper sheets P is performed, as will be described below. 
         [0088]    Namely, the paper sheets P respectively placed, in the stacked condition, on the placing unit  14  are fed, one by one, to the transport unit  22  in the casing  12 , by the feeding unit  16 , successively, from the paper sheet P located at the lowermost layer, and then transported by the transport unit  22 . During this operation, the paper sheets P are recognized and counted by the recognition and counting unit  24 . In this case, each paper sheet P recognized as the normal paper sheet by the recognition and counting unit  24  is fed to the stacking unit  26  by the diverter  32 . At this time, the paper sheets P are arranged in the stacking unit  26  by the stacking wheel  28 . 
         [0089]    Meanwhile, each paper sheet that is not recognized as the normal paper sheet by the recognition and counting unit  24  and each paper sheet that cannot be recognized by the recognition and counting unit  24  are respectively fed, as the reject paper sheets P′, to the reject unit  30 , by the diverter  32 . Since the opening is provided in the front face of the reject unit  30 , the operator can take out such reject paper sheets P′ stacked in the reject unit  30 , via this opening. 
         [0090]    As described above, the maximum number of the reject paper sheets P′ that can be stored in the reject unit  30  is set, in advance. In this case, when the number of the reject paper sheets P′ fed to the reject unit  30  reaches the preset maximum number of the reject paper sheets P′ that can be stored therein, or when the reject unit  30  is full up with the reject paper sheets P′, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  22  of  FIG. 7 ), this condition of the reject unit  30  is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is once stopped. Thereafter, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  23  of  FIG. 7 ), sets again such reject paper sheets P′ on the placing unit  14 , and starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  24  of  FIG. 7 ). In this way, the counting process for the paper sheets P is started again in the paper-sheet counting machine  10 . In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0091]    Further, when the number of the paper sheets P respectively fed to the stacking unit  26  reaches the batch number inputted to the control unit  70 , or when one batch process is completed, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  25  of  FIG. 7 ), this condition or state is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is ended (STEP  26  of  FIG. 7 ). At this time, since the opening in the front face of the stacking unit  26  is kept opened, the operator can take out the paper sheets P stacked in the stacking unit  26 , via the opening in the front face of the stacking unit  26 . In this way, the operation of the paper-sheet counting machine  10  for one batch process is completed. Thereafter, when the operator starts again the counting process for the paper sheets P, via the operation unit  74 , the next batch process is performed as shown in the flow chart of  FIG. 7 . 
         [0092]    Meanwhile, when the number of the paper sheets P fed to the stacking unit  26  does not reach the batch number inputted to the control unit  70 , and when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14  (STEP  27  of  FIG. 7 ), this condition is displayed on the display unit  72 . Then, the reject-unit paper-sheet detection sensor  62  detects whether or not there are some reject paper sheets P′ remaining in the reject unit  30  (STEP  28  of  FIG. 7 ). As a result, when the reject-unit paper-sheet detection sensor  62  detects the reject paper sheets P′ remaining in the reject unit  30 , this condition is further displayed on the display unit  72 . Then, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  29  of  FIG. 7 ), sets again such reject paper sheets P′ on the placing unit  14 , and then starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  30  of  FIG. 7 ). In this way, the counting process for the paper sheets P in the paper-sheet counting machine  10  is started again. In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0093]    Meanwhile, when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , and when the reject-unit paper-sheet detection sensor  62  detects that there is no reject paper sheet P′ remaining in the reject unit  30 , if the operator inputs a command for terminating the counting process for the paper sheets P, to the control unit  70 , via the operation unit  74  (STEP  31  of  FIG. 7 ), the counting process for the paper sheets P in the paper-sheet counting machine  10  is ended (STEP  26  of  FIG. 7 ). At this time, since the opening in the front face of the stacking unit  26  is kept opened, the operator can take out the paper sheets P stacked in the stacking unit  26 , via the opening in the front face of the stacking unit  26 . 
         [0094]    Further, when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , and when the reject-unit paper-sheet detection sensor  62  detects that there is no reject paper sheet P′ remaining in the reject unit  30 , if the operator places additional paper sheets P on the placing unit  14  (STEP  32  of  FIG. 7 ), and then starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  33  of  FIG. 7 ), the counting process for the paper sheets P in the paper-sheet counting machine  10  is restarted. In place of the operator starting again the counting process for the paper sheets, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the additional paper sheets P on the placing unit  14 . 
         [0095]    In the operation of the paper-sheet counting machine  10  as shown in the flow chart of  FIG. 7 , as shown in the operation in the STEP  21  of  FIG. 7 , when the control unit  70  performs the counting process for the paper sheets P in the batch process mode, and when the batch number of the paper sheets P inputted to the control unit  70  is smaller than the preset number, the control unit  70  serves to retreat the shutter  40  from the opening provided in the front face of the stacking unit  26  to open this opening. Namely, in the case the batch number inputted to the control unit  70  is relatively small, if the opening and closing operation of the shutter  40  is performed for each batch process, the time required for the entire process for the paper sheets P becomes considerably long. Therefore, in this case, by keeping the opening opened in the front face of the stacking unit  26 , the time required for the entire process for the paper sheets P can be reduced. 
         [0096]    Next, referring to the flow chart of  FIG. 8 , the operation of the paper-sheet counting machine  10  will be further described, when the operator selects the batch process mode, and the batch number of the paper sheets inputted to the control unit  70  is equal to or greater than the preset number. 
         [0097]    Before starting the counting process for the paper sheets P by the recognition and counting unit  24 , the control unit  70  controls the shutter drive unit  50  to drive the shutter  40  to close the opening in the front face of the stacking unit  26  (STEP  41  of  FIG. 8 ). Then, the counting process for the paper sheets P is performed, as will be described below. 
         [0098]    Namely, the paper sheets P, respectively placed in the stacked condition on the placing unit  14 , are fed to the transport unit  22  in the casing  12 , one by one, by the feeding unit  16 , successively, from the paper sheet P located at the lowermost layer, and then transported by the transport unit  22 . At this time, the recognition and counting process for the paper sheets P is performed by the recognition and counting unit  24 . In this case, each paper sheet P recognized, as the normal paper sheet, by the recognition and counting unit  24  is fed to the stacking unit  26  via the diverter  32 . Then, the paper sheets P are arranged in the stacking unit  26 , by the stacking wheel  28 . At this time, since the opening in the front face of the stacking unit  26  is closed by the shutter  40 , the operator cannot take out the paper sheets P stacked in the stacking unit  26 . 
         [0099]    Meanwhile, each paper sheet that is not recognized as the normal paper sheet by the recognition and counting unit  24 , and each paper sheet that cannot be recognized by the recognition and counting unit  24  are respectively fed, as the reject paper sheets P′, to the reject unit  30 , via the diverter  32 . In this case, since the opening is provided in the front face of the reject unit  30 , the operator can take out the reject paper sheets P′ stacked in the reject unit  30 , via the opening. 
         [0100]    As described above, when the preset maximum number of the reject paper sheets P′ that can be stored in the reject unit  30  is set, and when the number of the reject paper sheets P′ fed to the reject unit  30  reaches the preset maximum number of the reject paper sheets P′ that can be stored therein or when the reject unit  30  is full up with such reject paper sheets P′, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  42  of  FIG. 8 ), this condition of the reject unit  30  is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is once stopped. Thereafter, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  43  of  FIG. 8 ), sets again such reject paper sheets P′ on the placing unit  14 , and starts again the counting process for the paper sheet P, via the operation unit  74  (STEP  44  of  FIG. 8 ). In this way, the counting process for the paper sheets P is started again in the paper-sheet counting machine  10 . In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0101]    Further, when the number of the paper sheets P respectively fed to the stacking unit  26  reaches the batch number inputted to the control unit  70 , or when one batch process is completed, during the counting process for the paper sheets P in the paper-sheet counting machine  10  (STEP  45  of  FIG. 8 ), this condition is displayed on the display unit  72 , and the counting process for the paper sheets P in the paper-sheet counting machine  10  is ended (STEP  46  of  FIG. 8 ). Thereafter, the control unit  70  controls the shutter drive unit  50  to move the shutter  40  to the opening position shown in  FIG. 2  form the closing position shown in  FIG. 1 . Thus, the opening in the front face of the stacking unit  26  is opened (STEP  47  of  FIG. 8 ), and then the operator takes out the paper sheets P stacked in the stacking unit  26 , via the opening in the front face of the stacking unit  26 . In this way, the operation of the paper-sheet counting machine  10  for one batch process is completed. Thereafter, when the operator starts again the counting process for the paper sheets P, via the operation unit  74 , the next batch process is performed as shown in the flow chart of  FIG. 8 . 
         [0102]    Meanwhile, when the number of the paper sheets P fed to the stacking unit  26  does not reach the batch number inputted to the control unit  70 , and when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14  (STEP  48  of  FIG. 8 ), this condition is displayed on the display unit  72 . Thereafter, the reject-unit paper-sheet detection sensor  62  detects whether or not there are some reject paper sheets P′ remaining in the reject unit  30  (STEP  49  of  FIG. 8 ). When the reject-unit paper-sheet detection sensor  62  detects that there are some reject paper sheets P′ remaining in the reject unit  30 , this condition is displayed on the display unit  72 . Thereafter, the operator takes out the reject paper sheets P′ from the reject unit  30  (STEP  50  of  FIG. 8 ), sets again such taken-out reject paper sheets P′ on the placing unit  14 , and then starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  51  of  FIG. 8 ). In this way, the counting process for the paper sheets P in the paper-sheet counting machine  10  is started again. In place of the operator starting again the counting process for the paper sheets P, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the reject paper sheets P′, respectively taken out form the reject unit  30 , on the placing unit  14 . 
         [0103]    Meanwhile, when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , and when the reject-unit paper-sheet detection sensor  62  detects that there is no reject paper sheet P′ remaining in the reject unit  30 , if the operator inputs a command for ending the counting process for the paper sheets P, to the control unit  70 , via the operation unit  74  (STEP  52  of  FIG. 8 ), the counting process for the paper sheets P in the paper-sheet counting machine  10  is ended (STEP  46  of  FIG. 8 ). Thereafter, the control unit  70  controls the shutter drive unit  50  to move the shutter  40  to the opening position shown in  FIG. 2  from the closing position shown in  FIG. 1 . Thus, the opening in the front face of the stacking unit  26  is opened (STEP  47  of  FIG. 8 ). Then, the operator takes out the paper sheets P stacked in the stacking unit  26 , via the opening in the front face of the stacking unit  26 . 
         [0104]    Meanwhile, when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , and when the reject-unit paper-sheet detection sensor  62  detects that there is no reject paper sheet P′ remaining in the reject unit  30 , if the operator places the additional paper sheets P on the placing unit  14  (STEP  53  of  FIG. 8 ), and starts again the counting process for the paper sheets P, via the operation unit  74  (STEP  54  of  FIG. 8 ), the counting process for the paper sheets P in the paper-sheet counting machine  10  is restarted. In place of the operator starting again the counting process for the paper sheets, via the operation unit  74 , the paper-sheet counting machine  10  may be configured to restart the counting process for the paper sheets P, automatically, therein, once the operator places the additional paper sheets P on the placing unit  14 . 
         [0105]    According to the operation of the paper-sheet counting machine  10  as shown in the flow chart of  FIG. 8 , as shown in the operation in the STEP  45  and STEP  48  of  FIG. 8 , when the control unit  70  performs the counting process for the paper sheets P in the batch process mode, and when the placing-unit-residue detection sensor  60  detects that there is no paper sheet P remaining on the placing unit  14 , if the number of the paper sheets P counted by the recognition and counting unit  24  does not reach the batch number, the control unit  70  controls the shutter drive unit  50  to drive the shutter  40  to keep closing the opening provided in the front face of the stacking unit  26 . Namely, in this case, as shown in the STEP  53  and STEP  54  of  FIG. 8 , it is necessary for the operator to place the additional paper sheets P on the placing unit  14  and start again the counting process for the paper sheets P, via the operation unit  74 . Therefore, even in the case the operation of the paper-sheet counting machine  10  is stopped, while the actual number of the paper sheets P fed to the stacking unit  26  is slightly short of the batch number inputted to the control unit  70 , this paper-sheet counting machine  10  can prevent the operator from misunderstanding that the batch process has been properly performed and thus the number of the paper sheets P stacked in the stacking unit  26 , at this point of time, is correctly corresponding to the batch number. Accordingly, this paper-sheet counting machine  10  can securely prevent the operator from mistakenly taking out the paper sheets P from the stacking unit  26 . 
         [0106]    Alternatively, in the operation of the paper-sheet counting machine  10  as shown in the flow chart of  FIG. 8 , the control unit  70  may control the shutter drive unit  50  to retreat the shutter  40  from the opening in the front face of the stacking unit  26  to open this opening, at a point of time that the paper-sheet tracking detection sensor  64  provided to the transport unit  22  detects the last paper sheet P of the batch number. With this operation, as compared with the case of starting to move the shutter  40  once the counting process for one batch process is completely finished or once the stacking-unit paper-sheet detection sensor  68  detects that the number of paper sheets P respectively fed to the stacking unit  26  reaches the batch number, the opening in the front face of the stacking unit  26  can be opened more rapidly, thereby to reduce the time required for the entire process for the paper sheets P. It is noted that interval of time between the time the paper-sheet tracking detection sensor  64  detects the last paper sheet P of the batch number and the time the control unit  70  controls the shutter drive unit  50  to retreat the shutter  40  from the opening in the front face of the stacking unit  26 , may be optionally altered, by the operator, with appropriate settings, via the operation unit  74 . In this case, the operator can optionally select the order of priority, between the dustproof or soundproofing in the paper-sheet counting machine  10  and the reduction of the time required for handling the paper sheets P. 
         [0107]    Further, as described above, the paper-sheet tracking detection sensor  64  is provided to the transport unit  22 , in such a position that interval of time between the time one paper sheet P is detected by the paper-sheet tracking detection sensor  64  and the time this paper sheet P is fed to the stacking unit  26 , is substantially matched with the time required for the shutter  40  to be moved from the closing position (see  FIG. 1 ) in which the opening in the front face of the stacking unit  26  is closed to the opening position (see  FIG. 2 ) in which the opening is opened. With this configuration, the opening in the front face of the stacking unit  26  can be just opened at the time the last paper sheet P of the batch number actually reaches the stacking unit  26  after this paper sheet P is detected by the paper-sheet tracking detection sensor  64 . As such, the operator can take out one batch of the paper sheets P stacked in the stacking unit  26 , just after the last paper sheet P of the batch number reaches the stacking unit  26 . 
         [0108]    As stated above, according to the paper-sheet counting machine  10  of this embodiment, the opening and closing operation for the opening provided in the front face of the stacking unit  26  can be optionally performed by the shutter  40  driven by the shutter drive unit  50  controlled by the control unit  70 . Therefore, the opening provided in the front face of the stacking unit  26  can be selectively closed by the shutter  40 . Thus, when this shutter  40  closes the opening, the blowing out of the dust accumulated in the casing  12  of the paper-sheet counting machine  10  and/or dust attached to each paper sheet, toward the operator, can be successfully prevented. Further, when the shutter  40  closes the opening in the front face of the stacking unit  26 , the unwanted leakage of the sound generated in the interior of the paper-sheet counting machine  10  to the outside can be effectively prevented during the operation of the machine  10 . 
         [0109]    It is noted that the paper-sheet counting machine according to the present invention is not limited to such an aspect as described above. For instance, any suitable variations or modifications can be made to the mechanism for driving the aforementioned shutter of the paper-sheet counting machine shown in  FIGS. 3 and 4 . 
         [0110]      FIGS. 9 and 10  respectively show one variation of the driving mechanism for driving the shutter in the paper-sheet counting machine of the present invention. Of these drawings,  FIG. 9  shows one side view for illustrating the construction of the shutter, shutter support unit for supporting the shutter, shutter drive unit, a plurality of gears, torque limiter and the like, respectively provided in the paper-sheet counting machine related to one variation of the present invention.  FIG. 10  shows one top view for illustrating the shutter, shutter support unit for supporting the shutter, shutter drive unit, a plurality of gears, torque limiter and the like, respectively shown in  FIG. 9 , when such units or parts are respectively seen from above. It is noted that  FIG. 9  is provided for illustrating the construction of the shutter and the like when the shutter closes the opening provided in the front face of the stacking unit. 
         [0111]    In the shutter drive mechanism of the paper-sheet counting machine in the variation of the present invention as shown in  FIGS. 9 and 10 , like parts or units are respectively designated by like reference numerals respectively shown in  FIGS. 1 through 5 . 
         [0112]    As shown in  FIGS. 9 and 10 , a first gear  80  is attached to the shutter drive unit  50  composed of the motor, such that this first gear  80  is rotated by the shutter drive unit  50  in both of the clockwise and anticlockwise directions in  FIG. 9 . Further, a second gear  81  substantially larger, in size, than the first gear  80  is provided in the vicinity of the first gear  80 . The first and second gears  80  and  81  are meshed with each other. Thus, the rotation force is transmitted from the first gear  80  to the second gear  81 . 
         [0113]    On one side face of the second gear  81  (more specifically, on an upper side face of the second gear  81  in  FIG. 10 ), a third gear  82  substantially smaller, in size, than the second gear  81  is attached. The second and third gears  81  and  82  respectively have the same rotation shaft extending in one straight line. Thus, when the second gear  81  is rotated, the third gear  82  is rotated in synchronism with the second gear  81 . Further, a fourth gear  83  substantially larger, in size, than the third gear  82  is provided in the vicinity of the third gear  82 . Such third and fourth gears  82  and  83  are meshed with each other. Thus, the rotation force is transmitted from the third gear  82  to the fourth gear  83 . 
         [0114]    On one side face of the fourth gear  83 , a fifth gear  85  substantially smaller, in size, than the fourth gear  83  is attached, via a torque limiter  84 . Such fourth and fifth gears  83  and  85  have the same rotation shaft extending in one straight line. Thus, when the fourth gear  83  is rotated, the fifth gear  85  is rotated in synchronism with the forth gear  83 . In this case, if the rotation force greater than a preset torque is applied to the torque limiter  84  provided between the fourth gear  83  and the fifth gear  85 , the connection between the fourth gear  83  and the fifth gear  85  is released, and then the fifth gear  85  will be rotated freely relative to the fourth gear  83 . 
         [0115]    In addition, a sixth gear  86  substantially larger, in size, than the fifth gear  85  is provided in the vicinity of the fifth gear  85 . Such fifth and sixth gears  85  and  86  are meshed with each other. Thus, the rotation force is transmitted from the fifth gear  85  to the sixth gear  86 . Further, the sixth gear  86  is attached to the shutter support unit  42  for supporting the shutter  40 . Therefore, the sixth gear  86  is rotated integrally with the shutter support unit  42  about a shaft  86   a.    
         [0116]    A first notched portion  86   b  and a second notched portion  86   c  are respectively provided to the sixth gear  86 . Additionally, the shutter-closing detection sensor  54   a  and shutter-opening detection sensor  54   b  are respectively fixed in position, in the vicinity of the sixth gear  86 . Each of such shutter-closing detection sensor  54   a  and shutter-opening detection sensor  54   b  is composed of the optical sensor. In this case, when the shutter  40  is located in the closing position, the position of the first notched portion  86   b  of the sixth gear  86  is substantially matched with the position of the shutter-closing detection sensor  54   a.  Therefore, the detection of the first notched portion  86   b  of the sixth gear  86  by the shutter-closing detection sensor  54   a  indicates the detection of the shutter  40  located in the closing position. Meanwhile, when the shutter  40  is located in the opening position, the position of the second notched portion  86   c  of the sixth gear  86  is substantially matched with the position of the shutter-opening detection sensor  54   b.  Therefore, the detection of the second notched portion  86   c  of the sixth gear  86  by the shutter-opening detection sensor  54   b  indicates the detection of the shutter  40  located in the opening position. 
         [0117]    Now, the operation of the shutter drive mechanism of the paper-sheet counting machine related to the variation of the present invention, as shown in  FIGS. 9 and 10 , will be described. 
         [0118]    In the case of driving the shutter  40  to move to the opening position from the closing position shown in  FIG. 9 , the shutter drive unit  50  composed of the motor serves to rotate the first gear  80  in the clockwise direction in  FIG. 9 . Thus, the driving force exerted from the shutter drive unit  50  is transmitted, from the first gear  80 , through the second gear  81 , third gear  82 , fourth gear  83 , torque limiter  84  and fifth gear  85 , up to the sixth gear  86 , as such the sixth gear  86  is rotated in the clockwise direction in  FIG. 9  about the shaft  86   a.  Therefore, the shutter support unit  42  attached to the sixth gear  86  is also rotated in the clockwise direction in  FIG. 9  about the shaft  86   a.  As a result, the shutter  40  is moved from the closing position as shown in  FIG. 1  to the opening position as shown in  FIG. 2 . 
         [0119]    Meanwhile, in the case of driving the shutter  40  to move to the closing position from the opening position, the shutter drive unit  50  composed of the motor serves to rotate the first gear  80  in the anticlockwise direction in  FIG. 9 . In this way, the driving force exerted from the shutter drive unit  50  is transmitted, from the first gear  80 , through the second gear  81 , third gear  82 , fourth gear  83 , torque limiter  84  and fifth gear  85 , up to the sixth gear  86 , as such the sixth gear  86  is rotated in the anticlockwise direction in  FIG. 9  about the shaft  86   a.  Thus, the shutter support unit  42  attached to the sixth gear  86  is also rotated in the anticlockwise direction in  FIG. 9  about the shaft  86   a.  As a result, the shutter  40  is moved from the opening position as shown in  FIG. 2  to the closing position as shown in  FIG. 1 . 
         [0120]    As described above, the torque limiter  84  is provide between the shutter support unit  42  for supporting the shutter  40  and the shutter drive unit  50 . Therefore, in the case the operator moves the shutter  40  downward, by hand, from the closing position shown in  FIG. 1 , when the force applied from the operator to the torque limiter  84  is greater than the preset torque, the torque limiter  84  releases the connection between the fourth gear  83  and the fifth gear  85 . As such, the fifth gear  85  can be rotated freely relative to the fourth gear  83 . Namely, in this case, the torque limiter  84  serves to block the driving force of the shutter drive unit  50  to be transmitted to the shutter  40 . Therefore, even in the period during which the counting process for the paper sheets P is performed by the recognition and counting unit  24 , the operator can move the shutter  40  downward, by hand, from the closing position shown in  FIG. 1 , thereby to take out the paper sheets P from the stacking unit  26 . 
         [0121]    Further, even in the case the hand or the like of the operator is placed in the stacking unit  26  in a period during which the shutter  40  is moved from the opening position shown in  FIG. 2  to the closing position shown in  FIG. 1 , if the force applied to the torque limiter  84  becomes greater than the preset torque once the shutter is in contact with such a hand or the like of the operator, the torque limiter  84  releases the connection between the fourth gear  83  and the fifth gear  85 , thus allowing the fifth gear  85  to be rotated freely relative to the fourth gear  83 . In this way, the torque limiter  84  serves to block the driving force of the shutter drive unit  50  to be transmitted to the shutter  40 . Thus, the shutter  40  is stopped when this shutter  40  is in contact with the hand or the like of the operator, thereby successfully preventing such trouble that the finger or the like of the operator is seriously nipped and injured by the shutter  40 .