Abstract:
A stapler includes a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple cartridge, a staple former, and a staple driver. The staple cartridge is further removable from a portion of the mounting unit including the staple former and the staple driver when the mounting unit is removed from the frame to permit replacement of the staple cartridge of the mounting unit. The mounting unit can further include a staple advancing mechanism and a reverse motion stopping mechanism.

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 09/873,268 filed on Jun. 5, 2000, now U.S. Pat. No. 6,568,579. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a stapler used to staple a stack of paper discharged from an image forming device such as a photocopier or a printer. 
     BACKGROUND 
     The following is an explanation of the stapling operation of a prior art stapler with reference to FIG.  1  and FIG.  2 . The sheet of staples S shown in FIG. 1 consists of a series of single staples. The sheet of staples S is rolled up and housed in the housing unit  50   a  of the cartridge  50 . Here, the sheet of staples S extends from the extraction opening  50   b  in the housing unit  50   a . The cartridge  50  mounted in the housing unit  50   a  has a pair of walls  50   c ,  50   c  separated at a specific interval as an extension of the extraction opening  50   b . The interval between the walls  50   c ,  50   c  is roughly equal to the width of the sheet of staples S. Therefore, the sheet of staples S extending from the extraction opening  50   b  passes between the walls  50   c ,  50   c  in the direction of the arrow shown in FIG.  1 . 
     Guides  51 ,  51  are placed on the cartridge  50  to prevent the sheet of staples S from riding up from the extraction opening  50   b . In other words, the sheet of staples S is restrained widthwise by wall  100   c  and prevented from riding up by the guides  51 ,  51  so as to travel in the direction of the arrow. As shown in FIG. 1, a plate  52  is extended between the side walls  50   c ,  50   c , and a reverse motion stopping tab  52   a  is formed on both ends of the plate  52 . The reverse motion stopping tab  52   a  makes contact with the sheet of staples S to prevent the sheet of staples S from moving in the direction opposite to the arrow back into the housing unit  50   a . In other words, the sheet of staples S moves in the direction of the arrow shown in FIG. 1, and is not allowed to return to the housing unit  50   a.    
     The cartridge  50  is mounted in the main body of the device  70  shown in FIG. 2, and the pressure unit  53  formed in the cartridge  50  is brought to bear when the cartridge is mounted on the spring plate  55  on the advancing unit  54  of the main body of the device  70 . The pressure from the spring plate  55  keeps the advancing unit  54  in the position shown in FIG.  2 . When the driver  56  applying the staples is lowered from the position shown in FIG. 2, the protrusion  56   a  on the driver  56  is brought to bear on the protruding plate  54   a  formed on the advancing unit  54 . Therefore, the lowering force of the driver  56  is communicated to the advancing unit  54  via the protrusion  56   a  and the protruding plate  54   a , and the advancing unit  54  resists the spring action of the spring plate  55  and is rotated counterclockwise in the drawing. When the advancing unit  54  has traveled a fill stroke, the protrusion  56   a  passes the position of the protruding plate  54   a . When the protrusion  56   a  passes the position of the protruding plate  54   a , the advancing unit  54  becomes free, and the advancing unit  54  subjected to the force of the spring  55  returns to its original position as shown in the figure. 
     An advancing tab  57  is located on the advancing unit  54 . This advancing tab  57  makes elastic contact with the sheet of staples S extending from the cartridge  50 . Therefore, the rotation of the advancing unit  54  causes the advancing tab  57  to advance the sheet of staples S in the direction of the driver  56 . When the advancing unit  54  rotates counterclockwise, the advancing tab  57  makes and maintains elastic contact with the sheet of staples S. When the advancing unit  54  rotates counterclockwise, force is applied to return the sheet of staples S. However, the reverse motion stopping tab  52   a  prevents the sheet of staples from returning. 
     Often several cartridges are provided containing rolled sheets of staples of varying lengths. These cartridges can be replaced to provide the desired type of staples. 
     When a cartridge  50  is replaced in a stapler, the cartridge  50  is removed with the advancing tab  57  bearing down on the sheet of staples S. When a cartridge  50  is removed with the advancing tab  57  bearing down on the sheet of staples S, the sheet of staples S is pulled out from the cartridge  50 . Because the revere movement stopping tab  52   s  bears down on the pulled out sheet of staples S, the staples do not return to their original position. As a result, some of the staples in the sheet of staples S are wasted. 
     Sometimes the cartridge  50  is divided in two and only the sheet of staples in the housing unit is replaced. However, even though the cartridge  50  is divided in two, the reverse motion stopping tab  52   a  continues to function and the section of the sheet of staples S drawn out by the reverse motion stopping tab  52   a  does not return to its original position. As a result, the section of the sheet of staples is wasted. 
     Therefore, there remains a need for a stapler that does not waste any staples when a staple cartridge or sheet of staples is replaced. 
     SUMMARY OF THE INVENTION 
     The invention relates to a stapler device including a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple cartridge, a staple advancing mechanism, a staple former, and a staple driver. In one embodiment, the stapler device further includes a motor coupled to the frame. 
     In one aspect of the invention, the staple cartridge is configured to be removed from a portion of the mounting unit including the staple advancing mechanism, the staple former, and the staple driver when the mounting unit is removed from the frame. In another aspect of the invention, when the mounting unit is attached to the frame, the staple advancing mechanism is in a first position that permits the staple advancing mechanism to engage staples to be fed from the staple cartridge, and when the mounting unit is removed from the frame, the staple advancing mechanism is in a second position that prevents the staple advancing mechanism from engaging the staples to be fed from the staple cartridge. The staple advancing mechanism can be automatically movable between the first and second positions when the mounting unit is attached to and removed from the frame. 
     In yet another aspect of the invention, the mounting unit further includes a reverse motion stopping mechanism. The reverse motion stopping mechanism is engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame, and the reverse motion stopping mechanism is disengaged from the staples to be fed from the staple cartridge when the mounting unit is removed from the frame. The reverse motion stopping mechanism can be automatically engaged with the staples to be fed from the staple cartridge when the mounting unit is attached to the frame, and the reverse motion stopping mechanism can be automatically disengaged from the staples to be fed from the staple cartridge when the mounting unit is removed from the frame. 
     The invention also relates to a method of removing a staple cartridge from a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple advancing mechanism, a staple former, a staple driver, and the staple cartridge. The method includes removing the mounting unit from the frame such that each of the staple advancing mechanism, the staple former, the staple driver, and the staple cartridge are separated from the frame but remain coupled together in the mounting unit. In one aspect, the method further includes, after removing the mounting unit from the frame, removing the staple cartridge from a portion of the mounting unit including the staple advancing mechanism, the staple former, and the staple driver. 
     The invention further relates to a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple cartridge, a staple former, and a staple driver. The staple cartridge is further removable from a portion of the mounting unit including the staple former and the staple driver when the mounting unit is removed from the frame to permit replacement of the staple cartridge of the mounting unit. In one aspect of the invention, the mounting unit further includes one or both of a staple advancing mechanism and a reverse motion stopping mechanism. 
     The invention also relates to a method of removing a staple cartridge from a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple former, a staple driver, and the staple cartridge. The method includes removing the mounting unit from the frame such that each of the staple former, the staple driver, and the staple cartridge are separated from the frame but remain coupled together in the mounting unit. After removing the mounting unit from the frame, the method further includes removing the staple cartridge from a portion of the mounting unit including the staple former and the staple driver to permit replacement of the staple cartridge of the mounting unit. 
     In one aspect of the invention, the mounting unit further includes a staple advancing mechanism positioned to be engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame. Removing the mounting unit from the frame includes automatically repositioning the staple advancing mechanism so that the staple advancing mechanism cannot engage the staples to be fed from the staple cartridge. 
     In another aspect of the invention, the mounting unit further includes a reverse motion stopping mechanism engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame. Removing the mounting unit from the frame includes automatically disengaging the reverse motion stopping mechanism from the staples to be fed from the staple cartridge. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a cartridge of the prior art. 
     FIG. 2 is a cross-sectional view of a stapler of the prior art. 
     FIG. 3 is a lateral view of the stapler of the present invention. 
     FIG. 4 is a cross-sectional view of the mounting unit. 
     FIG. 5 is a cross-sectional view of the mounting unit during the operation of the driver mechanism. 
     FIG. 6 is a cross-sectional view of the mounting unit when the mounting unit has been removed from the stapler. 
     FIG. 7 is a perspective view of the frame and the mounting unit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is an explanation of a first embodiment of the present invention with reference to FIG.  3  through FIG.  7 . FIG. 3 is a side view of the device  1  in the embodiment of the present invention. The front of the device  1  is on the left in the drawing and the back of the device  1  is on the right in the drawing. 
     As shown in FIG.  3  through FIG. 7, the mounting unit  3  is installed on the frame  2  of the device  1 . As shown in FIG. 4, the cartridge  4  is installed on the back of the mounting unit  3 . A sheet of staples S consisting of individual staples S 1  is housed in the cartridge  4 . 
     As shown in FIG. 7, the front block  5  of the device  1  is equipped with a driver mechanism  6  for driving a staple S 1  through a stack of paper. As shown in FIG. 4, an advancing mechanism  7  is installed to advance a staple S 1  to the driver mechanism  7 . What follows is a detailed explanation of the driver mechanism  6  and the advancing mechanism  7 . 
     As shown in FIG. 3, the side of the device  1  is equipped with a driver mechanism for operating the driver mechanism  6  and the advancing mechanism  7 . FIG. 3 shows the stapling operation performed by the device  1 . Here, the driver mechanism is located in the home position. The stapling operation and the operation of the advancing mechanism  7  involve the up and down movement of the drive shaft  8  in front of the device in FIG.  3 . 
     As shown in FIG. 3, the device  1  is equipped with a drive motor  9 . The pinion  10  attached to the output shaft of the drive motor  9  engages the first relay gear  11 . The rotation of the output shaft from the drive motor  9  rotates the pinion  10  clockwise in FIG. 3, and the first relay gear  11  engaged with the pinion  10  is rotated counterclockwise. The first deceleration gear  13  is connected to the rotating shaft  12  of the first relay gear  11 . As a result, the rotation of the first relay gear  11  rotates the first deceleration gear  13  counterclockwise. 
     The first deceleration gear  13  engages the second relay gear  14 . Because the first deceleration gear  13  rotates counterclockwise, the second relay gear  14  rotates clockwise. The second deceleration gear  16  is attached to the rotating shaft  15  of the second relay gear  14 . As a result, the rotation of the second relay gear  14  rotates the second deceleration gear  16  clockwise. The second deceleration gear  16  engages the gear of the drive wheel  17 . When the second deceleration gear  16  rotates clockwise, the drive wheel  17  rotates counterclockwise. 
     An engagement pin  18  is attached to the drive wheel  17 . As shown in FIG. 3, the engagement pin  18  is attached near the outer edge of the drive wheel  17 . Also, the engagement pin  18  is inserted into the guide hole  19   a  in the driver arm  19 . As a result, the movement of the engagement pin  18  is rotational around the center of the shaft  20 . Here, the rotation of the drive wheel  17  moves the tip of the driver arm  19  up and down. 
     Both sides of the device  1  are equipped with a first deceleration gear  13 , a second relay gear  14 , a second deceleration gear  16  and a drive wheel  17 . 
     A driver arm  19  is situated on both sides of the device  1 . The tip of the driver arm  19  on both sides bends back to the rear, and a groove  19   b  is formed in the bent back portion. The driver shaft  8  extends between the grooves  19   b  in the driver arm  19  on both sides. 
     Because the driver shaft  8  is inserted into the grooves  19   b  in the driver arms  19 , the driver shaft  8  moves up and down with the up and down movement of the front of the driver arms  19 . The driving force of the drive motor  9  moves the driver shaft  8  up and down. The drive wheel  17  has a sensor  22  consisting of an attached cam  21  and a remit switch to detect the home position. The cam  21  turns the remit switch on in the home position. When the drive wheel  17  rotates once and returns to the home position, the sensor  22  identifies the home position and stops the drive motor  9 . 
     The mounting unit  3  equipped with the driver mechanism  6  and advancing mechanism  7  for performing the stapling operation has the following configuration. FIG. 4 is a cross-sectional view of the mounting unit  3  when the driver mechanism is in the home position. FIG. 6 is a cross-sectional view of the mounting unit when the mounting unit has been removed from the stapler. The mounting unit  3  is equipped with the cartridge  4  and the front block  5  shown in FIG. 7 as well as the advancing mechanism  7  shown in FIG.  4 . 
     A pair of roller supports  4   a  is situated on the bottom of the cartridge  4  installed in the mounting device  3 . A shaft  4   b  extends between the roller supports  4   a . A roller  23  is installed on the shaft  4   b  so as to rotate freely. A guide plate  4   c  is installed above the roller  23 , and the sheet of staples S passed between the roller  23  and the guide plate  4   c . When the sheet of staples S passes through, the roller  23  rotates and the sheet of staples S is extended out smoothly. 
     When the mounting unit  3  is installed in the device (not shown), the roller  23  makes contact with a plate-like roller guide. Therefore, when the mounting unit  3  is installed in the device, the roller  23  rotates and makes contact with the roller guide. The rotation of the roller  23  extends the sheet of staples S between the roller  23  and the guide plate  4   c . When the end of sheet of staples S is extended to a certain position explained below, the roller  23  slips. 
     When the mounting unit  3  is installed in a certain position, the roller extends out from the roller guide and rotates freely. When the roller  23  extends out from the roller guide, the force of the extended sheet of staples S rotates the roller  23  and the sheet of staples S is extended out smoothly. 
     The following is an explanation of the front block  5  with reference to FIG.  4  and FIG. 7. A specific interval is established between the sheath  24  and the face plate  25  as shown in FIG.  4 . The former  26  and the driver mechanism  6  are placed in between. 
     The driver shaft  8  then moves up and down to perform the following stapling operation. When the driver shaft  8  is lowered as shown in FIG. 4, the former  26  bends a staple S 1  into an angular C-shape. When the driver shaft  8  is lowered again, angular C-shaped staple S 1  is pressed by the driver mechanism  6  through a stack of paper. The position of the driver shaft  8  when applying pressure to the staple S 1  is shown in FIG.  3 . 
     The following is an explanation of the advancing mechanism  7  with reference to FIG.  4 . The advancing mechanism  7  is equipped with a box-shaped advancing mechanism casing  27 . The advancing mechanism casing  27  houses various elements with the following configuration. 
     The advancing mechanism casing  27  is installed in the mounting unit  3  so as to be able to move up and down. In other words, a pair of side wall plates  28   a ,  28   b  are in stalled in the mounting unit  3  as shown in FIG. 7, and a guide plate  29   a  and a front block plate  29   b  are placed between the side wall plates  28   a ,  28   b . The side wall plates  28   a ,  28   b , the guide plate  29   a  and the front block plate  29   b  form a housing space  30 . The advancing mechanism casing  27  is installed in the housing space so as to be able to move up and down. 
     The upper ends of a pair of coil springs  31  compressed against the ceiling are attached to the advancing mechanism casing  27 . The bottom ends of the pair of compressed coil springs  31  are fixed to the side wall plates  28   a ,  28   b . The configuration is as follows. The side of the advancing mechanism casing  27  has a long hole  32  as shown in FIG. 3, and a spring receiving plate  33  is fixed inside the side wall plates  28   a ,  28   b . The spring receiving plate  33  extends inside the advancing mechanism casing  27  from the long hole  32 , and the bottom end of the compressed coil spring  31  is fixed to the extended end portion. 
     Therefore, the advancing mechanism casing  27  is maintained as shown in FIG. 7 so the ceiling extends above the side wall plates  28   a ,  28   b  to the extend it is acted upon by the force. As shown in FIG. 7, when the force acts on the ceiling, the advancing mechanism casing  27  is lowered against the spring action of the compressed coil spring  31 . 
     Also, a shaft  34  is fixed between the side plates of the advancing mechanism casing  27 , and the rotating unit  35  is attached to the shaft  34  so as to rotate freely. A protrusion  35   a  is formed in the upper rear section of the rotating unit  35 , and one end of a coil spring  36  is attached to the protrusion  35   a  to apply spring action to the rotating unit  35 . The spring action causes the rotating unit  35  to rotate counterclockwise as shown in FIG.  4 . 
     A cam surface  35   b  is formed in the front of the rotating unit  35 . The cam surface  35   b  moves along a track with the up and down movement of the driver shaft  8 . As a result, the rotating unit  35  being acted upon by the spring also rotates with the up and down movement of the driver shaft  8 . 
     Two stationary pins  37 ,  38  are formed on the bottom of the side plates in the advancing mechanism casing  27 , and an moving plate  39  is attached to the stationary pins  37 ,  38 . A long hole  39   a  is formed in the moving plate  39 . The stationary pins  37 ,  38  pass through the long hole  39   a  so the moving plate  39  can move within the range of the long hole  39   a . The direction of movement for the moving plate  39  matches the direction of movement for the sheet of staples S. 
     The engagement pin  40  is fixed to the moving plate  39  above the long hole  39   a , and the engagement pin  40  is inserted into an engagement depression  35   c  formed in the rotating unit  35 . 
     Therefore, the rotating unit  35  rotates counterclockwise in FIG. 4 around shaft  34 , the engagement depression  35   c  slides, and the sliding moves the moving plate  39  forward. 
     The advancing tab  41  is fixed to the bottom of the moving plate  39 , and the reverse motion stopping tab  42 , which serves as the reverse motion restraining mechanism, is fixed to the bottom of the advancing mechanism casing  27 . The advancing tab  41  and the reverse motion stopping tab  42  move downwards on a slope from the cartridge  4  to the front block  5 . 
     When the advancing mechanism casing  27  resists the compressed coil spring  31  and moves downward as shown in FIG. 4, the advancing tab  41  and the reverse motion stopping tab  42  make contact with the sheet of staples S extending from the cartridge  4 . When the advancing tab  41  makes contact with the sheet of staples S, the sheet of staples S is advanced in contact with the advancing tab  41  if the moving plate  39  moves in the direction of the advancing sheet of staples S. 
     The reverse motion stopping tab  42  makes contact with the sheet of staples S but only allows movement in the direction of the advancing sheet of staples S. As a result, the sheet of staples S cannot move back. 
     The following is an explanation of the method used to attach the mounting unit  3  to the frame  2  with reference to the cutaway section of the frame  2  shown in FIG.  7 . In the mounting unit, upper support plates  45 ,  45  and lower support plates  46 ,  46  are attached to the outside of the side wall plates  28   a ,  28   b . In the frame  2 , upper guides  43 ,  43  and lower guides  44 ,  44  are attached to the inside of the side wall plates  2   a ,  2   b . The guides  43 ,  44  restrict the upward and downward movement of the support plates  45 ,  46  but allow them to pull apart. The guides  43 ,  44  have U-shaped stoppers on the end. When the support plates  45 ,  46  come into contact with the stoppers, the mounting unit  3  is installed in the appropriate position on the frame  2 . 
     A tiered advancing mechanism casing pressure unit  47  is installed on the ceiling of the frame  2 . When the mounting unit  3  is installed in the frame  2 , the lowest section  47   a  of the advancing mechanism casing pressure unit  47  presses the advancing mechanism casing  27  down and keeps it down as shown in FIG.  4 . The advancing tab  41  and the reverse motion stopping tab  42  on the mounting unit  3  come into contact with the sheet of staples S. 
     When the driver shaft  8  is lowered to the home position as shown in FIG. 4, the driver shaft  8  resists the spring action of the coil spring  36  and presses down the cam surface  35   b  of the rotating unit  35 . This rotates the rotating unit  35  counterclockwise as shown in FIG.  4 . 
     If the rotating unit  35  is rotated counterclockwise, the moving plate  39  is moved towards the back of the cartridge  4 . As a result, the advancing tab  41  attached to the moving plate  39  is also moved towards the cartridge  4 . 
     Because the advancing tab  41  moves downward at a slope from the cartridge  4  to the front block  5 , the advancing tab  41  applies returning force to the sheet of staples S when the advancing tab  41  moves toward the cartridge  4 . 
     However, because there is a reverse motion stopping tab  42  making contact with the sheet of staples S beneath the advancing mechanism casing  27 , the sheet of staples S cannot move back into the cartridge  4 . 
     Because the sheet of staples S is prevented from moving back into the cartridge  4 , there is no “firing of blanks” during the stapling operation. 
     When the moving plate  39  moves backward and the driver shaft  8  is at the lowest position as shown in FIG. 5, the driver shaft  8  begins to move upward. When the driver shaft  8  rises, the rotating unit  35  rotates clockwise in the figure and expands the coil spring  36 . The moving plate  39  moves forward, the sheet of staples S in contact with the advancing tab  41  also moves forward. The amount of movement is equivalent to the thickness of a single staple S 1 . 
     When the operation of the advancing mechanism  7  is repeated, the sheet of staples S is continuously advanced toward the driver mechanism  6 . 
     The advancing mechanism and the reverse motion preventing mechanism on the advancing mechanism are not restricted to plate-like tabs such as the advancing tab  41  and the reverse motion stopping tab  42 . The advancing mechanism and the reverse motion preventing mechanism on the advancing mechanism can also be a rotating mechanism such as a roller or an endless belt. 
     The following is an explanation of the method used to remove the cartridge  4  housing the sheet of staples S from the mounting unit  3  with reference to FIG.  4 . When the cartridge  4  is removed from the mounting unit, the mounting unit  3  has to first be removed from the device  1 . 
     If the mounting unit  3  is removed from the device  1 , the advancing mechanism casing  27  in the mounting unit  3  has to be released from the casing pressure unit  47 . As a result, the advancing mechanism casing  27  is raised by the spring action of the compressed coil spring  31 . In the raised position, the advancing tab  41  and the reverse motion stopping tab  42  are maintained at a position away from the sheet of staples S. The raised position is maintained by the spring receiving plate  33  coming into contact with the bottom of the long hole  32 . 
     Because the advancing tab  41  and the reverse motion stopping tab  42  are maintained at a position away from the sheet of staples S when the mounting unit  3  is removed from the device  1 , the advancing tab  41  and the reverse motion stopping tab  42  do not bear down on the sheet of staples S when the cartridge  4  is removed from the mounting unit  3 . As a result, the sheet of staples S is not extended from the cartridge  4  when the cartridge  4  is removed from the mounting unit  3 . 
     Because the reverse motion stopping tab  42  is separated from the staples, the extended section of the sheet of staples S simply returns to the cartridge  4 . As a result, the extended section of the sheet of staples S is not severed and wasted. 
     Because the reverse motion stopping tab  42  is attached to the advancing mechanism  7  of the sheet of staples in the mounting unit  3  and the reverse motion stopping tab  42  is not attached to the cartridge  4 , the extended section of the sheet of staples S extracted from the cartridge  4  in the mounting unit  3  by the advancing tab  41  can be returned. 
     In other words, the advancing tab  41  and the reverse motion stopping tab  42  are automatically released from the sheet of staples S by the spring action of the coil spring  39  attached to the advancing mechanism  7  when the mounting unit  3  is removed. Also, the staples do not remain extended when the cartridge  4  is extracted. 
     If the advancing tab  41  and the reverse motion stopping tab  42  in this embodiment are replaced by a rubber rotating unit, the force with which the rotating unit makes contact with the sheet of staples S is weaker when the cartridge  4  is removed. 
     When the mounting unit  3  is removed from the device  1 , the advancing tab  41  and the reverse motion stopping tab  42  are separated from the sheet of staples S by the spring action of the compressed coil spring  31 . The advancing mechanism  7  can also be raised manually. 
     Since the advancing tab  41  and the reverse motion stopping tab  42  make contact with the sheet of staples S and separate from the sheet of staples S, the mounting unit  3  can have the following configuration. In this configuration, the pressure unit  47  can be placed on the frame  2 . 
     The upper end of the side walls  28   a ,  28   a  in the mounting unit  3  are bend inward, and a plate is manually inserted from the end with the driver mechanism  6  between the bent portion and the advancing mechanism casing  27 . When the plate is inserted between the bent portion and the advancing mechanism casing  27  in this configuration, the plate bears down on the advancing mechanism casing  27 . The advancing tab  41  and the reverse motion stopping tab  42  make contact with the sheet of staples S and are maintained in this position. When the plate is removed from between the bent section and the advancing mechanism casing  27 , the advancing mechanism casing  27  extends upwards and the advancing tab  41  and the reverse motion stopping tab  42  are separated from the sheet of staples S. 
     The following is an explanation of another configuration. A mechanism that locks when the advancing mechanism casing  27  is pressed down can be attached to the mounting unit  3 . When the advancing mechanism casing  27  is pressed down manually, the locking mechanism makes sure the pressure unit  47  applies pressure to the advancing mechanism casing  27 . The locking mechanism can be released by operating a button or lever. In this configuration, the mounting unit  3  is installed in the device  1 , and the advancing tab  41  and the reverse motion stopping tab  42  come into contact with the sheet of staples S. The advancing tab  41  and the reverse motion stopping tab  42  can be released from the sheet of staples S by operating a button or lever. Here, the plate, button and lever are manually operated units. In this configuration, the device  1  and the mounting unit  3  are integrated and the cartridge  4  is extracted without removing the mounting unit  3 . 
     In one embodiment, a reverse motion stopping mechanism is installed in the device and the reverse motion stopping mechanism is separated from the sheet of staples by operating a control unit. As a result, the extended sheet of staples is returned to the cartridge when the cartridge is removed from the main body of the device. In another embodiment, the reverse motion stopping mechanism makes contact with the sheet of staples when the mounting unit is installed in the main body of the device, and the reverse motion stopping mechanism is released from the sheet of staples when the mounting unit is removed from the main body of the device. As a result, the extended sheet of staples is returned to the cartridge when the cartridge is removed from the main body of the device. 
     In another embodiment, the reverse motion stopping mechanism is mounted on the advancing mechanism and is released from the sheet of staples when the mounting unit is removed from the main body of the device. Because the advancing mechanism and the reverse motion stopping mechanism attached to the advancing mechanism do not act upon the sheet of staples when the cartridge is removed from the mounting unit, the sheet of staples is not extended unnecessarily. Because the reverse motion stopping mechanism is separated from the sheet of staples, the extended section of the sheet of staples simply returns to the cartridge when the sheet of staples has to be extended. As a result, the extended section of the sheet of staples is not wasted. 
     In another embodiment, the advancing mechanism casing is extended upwards by spring action when the mounting unit is removed from the main body of the device. As a result, the advancing mechanism and the reverse motion stopping mechanism are automatically released from making contact with the sheet of staples. 
     In another embodiment, the advancing mechanism and the reverse motion stopping mechanism make contact with the sheet of staples when the mounting unit is installed in the main body of the device. Even though the movement of the advancing mechanism towards the cartridge moves the sheet of staples towards the cartridge, the reverse motion stopping mechanism prevents movement of the sheet of staples towards the cartridge. Because the sheet of staples is prevented from returning to the cartridge, the device doesn&#39;t “fire blanks” during the stapling operation. 
     In one more embodiment, the mounting unit is mounted in the device and the advancing mechanism and the reverse motion stopping mechanism are separated from the sheet of staples by operating a button or lever. As a result, the sheet of staples is not unnecessarily extended when the cartridge is removed. 
     It should be understood that variations and modifications within the spirit and scope of the invention may occur to those skilled in the art to which the invention pertains. Accordingly, all expedient modifications readily attainable by one versed in the art from the disclosure set forth herein that are within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention accordingly is to be defined as set forth in the appended claims.