Abstract:
A document handling machine comprises a stapling device, and a staple cartridge operatively connected to the stapling device and including a staple estimating device adapted for measuring rotational movement of a roll of staples held within the staple cartridge and for estimating a quantity of the staples based on the measured rotational movement.

Description:
BACKGROUND 
   Printers, copiers and other such document handling equipment may use electric staplers as one of their components. These machines may be left unattended during copying, printing or otherwise handling a large number of documents, e.g., a large print job, wherein each of the documents produced may be held together with a staple. Prior to initiating a large print job the print operator may inspect the printer to ensure the printer contains the required number of consumables, such as toner, paper and staples, for example. The amount of paper and toner held in the printer may be estimated visually by the print operator. Paper and toner generally are typically held in the printer in a vertically orientated container so that the amount of paper and toner may be measured by the printer automatically by measuring the height of the consumable. In a printer that measures automatically the amount of paper and toner remaining, a warning may be displayed electronically on a display pad of the printer when these consumables are low. The amount of paper and toner remaining in the printer, therefore, can be ascertained without opening or otherwise visually inspecting the paper or toner storage areas. 
   Staples generally are provided in a roll such that a simple level, i.e., height, indicator is not sufficient to calculate, or estimate, the number of staples remaining in a cartridge. Accordingly, heretofore, determination of the number of staples remaining in a staple cartridge has been ascertained, or estimated, by manual, visual inspection of the staple cartridge. Some staple cartridges have been manufactured of transparent material so that the contents of the staple cartridge can be inspected without opening or removal of the cartridge from the printer or copier. While such a visual inspection method may be adequate for some users, visual inspection is generally not ideal in a high volume production environment, such as in a printing shop where a single operator may be operating multiple printers. Moreover, such a visual inspection method may not be convenient in a system where the printer is operated from a control device located at a remote site, such as from a computer located in another office or building. For example, an operator may order a print job at his or her computer, wherein the computer is located in a different area of the building from the printer. In such a case, visual inspection of the number of staples remaining in the printer would require the operator to leave his or her office, travel to the printer, visually inspect the number of staples remaining, and then return to his or her office to begin the print job. Moreover, visual inspection generally provides only a rough approximation of the number of staples remaining in a staple cartridge such that even after visual inspection, a print job may be halted due to lack of a sufficient number of staples to complete the print job. 
   Thus, for these and other reasons there is a need for the present invention. 
   SUMMARY 
   A document handling machine comprises a stapling device, and a staple cartridge operatively connected to the stapling device and including a staple estimating device adapted for measuring rotational movement of a roll of staples held within the staple cartridge and for estimating a quantity of the staples based on the measured rotational movement. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of a document handling machine including one embodiment of the staple counting device of the present invention, wherein the counting device is shown in dash lines. 
       FIG. 2  is a perspective view showing one embodiment of the staple counting device of  FIG. 1  wherein a staple strip and a measurement device located within the staple counting device are shown in dash lines. 
       FIG. 3  is a perspective view of the strip of staples of FIG.  2 . 
       FIG. 4  is a side view of the measurement device of the staple counting device of FIG.  1 . 
       FIG. 5  is a side cross-sectional view of the staple strip in an initial position according to an example embodiment. 
       FIGS. 6A  an  6 B are side cross-sectional views of the staple strip of FIG.  5  and the measurement device in an initial position and having been rotated from the position in FIG.  5  through an angle theta in accordance with an example embodiment. 
       FIG. 7  is a flow diagram of the method of staple calculation in accordance with an example embodiment. 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a front view of a document handling machine including one embodiment of the staple counting device of the present invention, wherein the counting device is shown in dash lines. Document handling machine  10  may comprise a printer, a copier or any other such document handling machine that may utilize a stapling device. For ease of illustration, machine  10  will be described using the example of a high-volume copier. Copier  10  comprises a housing  12  that encloses internal components therein and includes external components such as display and/or input pad  14 , and document output collation trays  16 . The internal components of copier  10  may include a print media tray or drawer  18  for holding a stack of print media  20 , a copying device  22 , a toner cartridge  24 , a stapling device  26 , also referred to as a stapler, and a staple cartridge  28 . Staple cartridge  28  includes therein a staple counting device  30 , as will be described in more detail below. During use, a sheet of print media  20  may be fed from tray  18  to copying device  22 , wherein toner cartridge  24  is connected to copying device  22 . After an image is copied on print media  20 , the sheet may be fed to collation tray  16 . After the copy job is completed, each of completed documents held on collation trays  16  may be stapled together by stapler  26  utilizing staples from staple cartridge  28 . In another embodiment, stapling commences before completion of the copy job. Details regarding one embodiment of a stapler are disclosed in U.S. Pat. No. 5,818,186, the disclosure of which is hereby incorporated by reference. 
     FIG. 2  is a perspective, partially cut-away view showing the staple counting device  30  of  FIG. 1  wherein a staple strip and a measurement device located within the staple counting device are shown in dash lines. Staple cartridge  28  includes staple counting device  30 , shown in dash lines, and a strip of staples  32 , also shown in dash lines. Strip  32  may comprise a long strip  32  of wires packed inside cartridge  28 . The strip  32  may include individual staples  34 , in an unbent, flat configuration, fastened together side by side such that the rear surface  36  of a staple is secured to the front surface  38  of the following staple. The individual staples  34  may be held together in strip  32  by any securement material, such as by adhesive or the like. The strip  32  is tightly wound so it takes the shape of a spiral  40 , with individual loops,  42  and  44 , for example, of the spiral  40  positioned directly on top of the previous loop. Accordingly, outer loop  42  is positioned directly on previous loop  44 . In the embodiment shown there is no wire material positioned centrally within the inner edge  46  of the spiral  40  so as to maintain a minimum radius of curvature  48  in order to prevent strip  32  from breaking. Each time that stapler  26  is operated, an endmost staple  50 , shown at opening  52  of cartridge  28 , is separated from the remainder of strip  32  and is formed into a “U” shaped wire. The “U” shaped wire is then forced by stapler  26  to penetrate through a document, and the ends then bent toward the document, to hold the document together as known in the art. 
   After endmost staple  50  is removed from strip  32 , the next staple  54  in strip  32  becomes the endmost staple of the strip. Endmost staple  54 , and the remainder of strip  32 , is then moved forward so that endmost staple  54  is positioned at opening  52  of cartridge  28 . Movement of strip  32  in forward direction  56  is accomplished by any known means. In one example, strip  32  is moved in direction  56  by pulling the end  54  of strip  32 . The force on strip  32  may comprise a magnetic force, a mechanical force or any other such force as may be sufficient to move the new endmost staple  54  into position at cartridge opening  52 . 
   Movement of endmost staple  54  of strip  32  will result in rotation of the centermost loop  58 , positioned at radius of curvature  48 , in a rotational direction  60 . Rotation of centermost loop  58  may be very small and slow, so that the rotation of strip  32  can be used to turn an adjusting knob  62  of a staple counting device  30 , such as a potentiometer  64 . 
     FIG. 3  is a perspective view of strip of staples  32 . Strip  32  may be positioned on a cylindrical core  66  wherein an outer diameter of core  66  defines radius of curvature  48  of strip  32 . A cap  68 , also referred to as a coupling member, may be placed on an end  70  of core  66  wherein cap  68  may include a cross bar  72  extending across a diameter of the cap  68 . Cross bar  72  may be sized to be received within a slot  74  (shown in  FIG. 4 ) of potentiometer adjusting knob  62 . Strip  32  may be secured on core  66  such that movement of strip  32  in rotational direction  60  will result in simultaneous movement of core  66 , and cap  68  secured thereto, in rotational direction  60 . Movement of cap  68  in rotational direction  60  will result in movement of crossbar  72  in rotational direction  60 , such that the cross bar  72  will simultaneously move potentiometer knob  62  ( FIG. 4 ) in rotational direction  60 . However, potentiometer  64  may be secured within housing  12  of copier  10  such that as potentiometer knob  62  is rotated in direction  60 , the remainder of potentiometer  64  will remain stationary within core  66 . 
     FIG. 4  is a side view of staple counting device  30 . Staple counting device  30  includes staple measurement device  64 , such as a compact, multi-turn potentiometer  64 . In the embodiment shown, potentiometer  64  comprises a potentiometer manufactured by Bourns, brandname Trimpot, and having part number 3006PDM3102W, though any suitable potentiometer may be used. Potentiometer  64  may include a housing  76  and knob  62  extending outwardly therefrom. Knob  62  may include a slot  74  adapted to receive therein cross bar  72  (see  FIG. 3 ) of cap  68  (see FIG.  3 ). A printed circuit board  80  may be secured to potentiometer  64 . Printed circuit board  80  may include three electric terminals  82 ,  84  and  86 , connected to corresponding wires  88 ,  90 , and  92 , respectively. Wires  88  and  90  may be used to provide a constant voltage to the ends of the potentiometer  64 . For example, wire  88  may provide a constant, positive voltage source and wire  90  may comprise a ground wire. Wire  92  may be used for transmitting a signal from the potentiometer  64 , or from an associated microprocessor (not shown), to an operator input and/or output device  94  positioned adjacent copier  10  or at a remote location. Device  94  may comprise a microprocessor and may include an input pad  96  for the input of instructions to copier  10  and a display screen  98  that may show the status of a print job and the quantity of consumables available within the copier, such as the amount of paper, toner and staples remaining in copier  10 . 
     FIG. 5  is a side view of the staple strip in an initially loaded position. In this view, staple strip  32  is new, or at a maximum length. As staples are dispensed from the strip  32 , the knob  62  rotates and varies the output of the potentiometer according to the angle through which the strip has rotated. If the potentiometer is linear, the voltage reading of the potentiometer  64  is an indicator of the angle that the core shaft  66  has rotated through. Accordingly, this angle of rotation may be associated with the amount of staples that have been removed from staple cartridge  28  to estimate the number of staples remaining in cartridge  28 . 
   A close approximation to the staple strip  32  is an Archimedes&#39; spiral. The last portion of strip  32 , i.e., the straight section of strip  32  that begins adjacent opening  52  of cartridge  28  and extends to the beginning of the curvature of strip  32 , does not describe a spiral trajectory, but rather a series of circle arcs and straight lines. One may calculate the arc length of the spiral and the length of the last portion and then divide this total length by the “width” of one staple, thereby calculating how many staples remain in cartridge  28 . In one embodiment where adhesive material is positioned between each staple, the “width” dimension of one staple will include the actual width dimension of the staple itself and the width dimension of adhesive on one side of the staple. In another embodiment where adhesive material is positioned along a backbone of the strip  32  of staples, and not between each staple, the “width” dimension of the staple will include only the actual width of an individual staple. Radius “r” may be calculated as the sum of the initial radius “Ro” plus the sum of the height “h” of a staple and the spacing “g” between adjacent loops of staples, multiplied by the angle of rotation “theta” divided by two pi “2π.” 
   In particular, the shape described by the staple strip may be similar to an Archimedes&#39; spiral, which is given by Equation 1:
 
 r=a⊖+b   Equation 1
 
The boundary conditions for this spiral are given in Equation 2:
 
at ⊖=0, then r=Ro, therefore, b=Ro,  Equation 2
 
where Ro is the base radius of spiral, i.e., the minimum radius of curvature  48 , described by a series of straight lines that join all the centroids of each staple wire. According, another boundary condition is given in Equation 3:
 
at ⊖=2π, then  r=Ro+h+g , therefore,  a =( h+g )/2π,  Equation 3
 
where g is the separation (gap) between two loops  42  and  44  of staples and h is the height of a staple wire. A differential of length of the roll  32  is given by Equation 4:
 
 ds =sqrt( r   2 +( dr/d ⊖) 2 ) d ⊖=sqrt(( a⊖+b ) 2   +a   2 ) · d⊖.   Equation 4
 
Accordingly, the length of the spiral can be obtained by integrating between the original angle of rotation of the potentiometer ⊖o and the final angle ⊖f, as shown in Equation 5:
 
 s =integral, from ⊖ o  to ⊖ f , of sqrt(( a⊖+b ) 2   +a   2 ) d⊖.   Equation 5
 
If we let ⊖o=0, then Equation 6 can be used to calculate the length s of the strip.
 
 s =(( b /2 a )+(⊖ f /2))·sqrt( a   2 +( b+a⊖f ) 2 )+(1/2) a ·ln(2( b+a⊖f )+2 sqrt( a   2 +( b+a⊖f ) 2 )−(( b /2 a )sqrt( a   2   +b   2 )+(1/2) a ·ln(2 b +2 sqrt( a   2   +b   2 )).  Equation 6
 
From the length s of strip  32 , one may calculate the number N of staples remaining in cartridge  28  from Equation 7.
 
 N=s/w , where w is the width of one staple.  Equation 7
 
     FIGS. 6A and 6B  are side views of the staple strip of FIG.  5  and staple counting device  30 , wherein  FIG. 6A  shows strip  32  in an initial position and  FIG. 6B  shows strip  32  having been rotated from the position in FIG.  6 A through an angle  100 . Accordingly,  FIG. 6B  shows potentiometer knob  62  having been rotated through the same angle  100  as strip  32 , by cross bar  72  (see  FIG. 3 ) of cap  68  (see  FIG. 3 ) of staple strip core  66 . 
     FIG. 7  is a flow diagram of one method of staple calculation of the present invention. In a first step  102  strip  32  rotates, thereby causing corresponding and simultaneous movement of core  66 , cap  68 , and potentiometer knob  62  through an angle  100 , referred to as angle “theta.” As shown in second step  104 , this rotation of potentiometer knob  62  changes the resistance of potentiometer  64 , wherein the resistance value is defined as the K constant “Kpot” of the potentiometer multiplied by angle “theta.” In third step  106 , the output voltage “V” is calculated as the resistance value “R” multiplied by the input voltage “Vc” divided by the initial resistance of the potentiometer “Rpot.” In fourth step  108 , an analog to digital converter (not shown) within potentiometer  64  converts the value of the output voltage “V” to a digital signal. In fifth step  110 , a microprocessor on circuit board  80  (see  FIG. 4 ) calculates angle “theta” as the output voltage “V” times the resistance of the potentiometer “Rpot” divided by the K constant “Kpot” of the potentiometer. In sixth step  112 , the microprocessor of circuit board  80  ( FIG. 4 ) calculates the length “s” of the remaining strip  32  of staples by the given equation 6, also recited above as Equation 6. In seventh step  114  the number “N” of stapes remaining in the cartridge  28  is calculated as the length “s” of the remaining strip  32  divided by the width “w” of a single staple, as shown in Equation 7 given above. 
   The illustrated embodiment of  FIGS. 1-7  is shown to illustrate the principles and concepts of the invention as set forth in the claims below, and a variety of modifications and variations may be employed in various implementations while still falling within the scope of the claims below.