Patent Document

FIELD OF THE INVENTION  
       [0001]     The present invention relates to media item feeding equipment, and more particularly, to a cut sheet feeder capable of simultaneously feeding multiple sheets to provide enhanced operation.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many types of office equipment, such as inserters and folders, have systems which feed sheets in a single sheet feeder format. In this arrangement, a sheet is singulated and fed from a stack of sheets and transported toward the process. A gap is provided and a subsequent sheet is singulated and passed on to the transport. The time to feed a single sheet is replicated with each sheet being fed. The time to feed three sheets is approximately three times the time to feed a single sheet. Accordingly, the throughput of the system goes down as each additional sheet is made part of any collations of sheets to be processed.  
         [0003]     In systems of the above type, efforts are made to ensure that the feeder does not double-feed or multiple-feed various sheets of paper. This will cause the system to be stopped. This is often termed stream feeding and involves multiple feeding of sheets as a single pack.  
         [0004]     It has been recognized that systems can be provided where multiple sheets are processed at a single time. For example, U.S. patent application Ser. No. 10/968,522 filed Oct. 19, 2004, in the names of Douglas B. Quine and Christopher A. Baker and entitled System And Method For Grouping Mail Pieces In A Sorter, assigned to Pitney Bowes Inc., disclose a method and system for processing of media items which includes a separator system feeding a series of media items onto a transport system. The separator system is controlled to feed onto the transport system groups of sequential media items having similar destination information and to separate and feed onto the transport system sequential media items having dissimilar destination information spaced apart on said transport system from the group of media items having similar destination information. The separator system may be controlled to limit the thickness of each group of media items not to exceed a predetermined thickness. The separator system may also be controlled to separate and feed onto the transport system any subsequent media items which would cause said group of media items to exceed the predetermined thickness.  
       SUMMARY OF THE INVENTION  
       [0005]     It is an object of the present invention to provide a media feeding arrangement that enhances the processing efficiency for media items by feeding a selectable number of media items as a group of media items.  
         [0006]     It is a further object of the present invention to provide a system which is adjustable to facilitate the use of various type media items to be processed such as media items of various length and of various materials having different coefficients of friction.  
         [0007]     A multiple media feed system embodying the present invention includes an adjustable media singulator feeder that is adjustable to feed from a stack of media items a selectable number of media items to form a group of overlapped media items. A thickness sensor is positioned to measure the thickness of media items fed from the stack of media items. A controllable media feeder is positioned to engage and feed media items fed from said stack of media items by the adjustable media singulator feeder. The controllable media feeder is controlled to feed media items when the thickness sensor has determined that the thickness of the selected number of media items is at the controllable media feeder.  
         [0008]     In a multiple media feed system, a method of feeding a selected number of media items from a stack of media items, a method embodying the present invention includes providing an adjustable singulating mechanism positioned to feed media items from the stack of media items. The drag force on the top media item in the stack of media items is measured. The adjustments of a singulator mechanism is set based on the measured drag force. The setting is such that the singulator mechanism separates from the stack of media items overlapped media items to form a group of media items of the selected number of media items. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Reference is now made to the various figures wherein similar reference numerals designate similar items in the various views and in which:  
         [0010]      FIG. 1  is a diagrammatic view of a multiple sheet feed performance enhancing system embodying the present invention, with a first media item staged at the nip of an arming drive roller and associated idler roller;  
         [0011]      FIG. 1   a  is a diagrammatic view of an overrunning dynamic clutch employed in the multiple sheet feeding performance enhancing system shown in  FIG. 1 ;  
         [0012]      FIG. 1   b  is a diagrammatic view of an overrunning static clutch employed in the multiple sheet feeding performance enhancing system shown in  FIG. 1 ;  
         [0013]      FIG. 2  is a diagrammatic view of the multiple sheet feed system shown in  FIG. 1  with a first media item being fed from a stack of media items;  
         [0014]      FIG. 3  is a diagrammatic view of the multiple sheet feed system shown in  FIG. 1  with a second media item being fed with the first media item;  
         [0015]      FIG. 4  is a diagrammatic view of the multiple sheet feed system shown in  FIG. 1  with a third media item being fed with the second media item and further including a downstream accumulator transport and accumulator gate;  
         [0016]      FIG. 5  is a flowchart of the operation of the multiple sheet feed system shown in  FIGS. 1-4 ; and,  
         [0017]      FIG. 6  is a flowchart of the process for setting the multiple sheet feed system parameters for operating the system shown in  FIGS. 1-5  to run a specific media item processing job as shown in  FIG. 5 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Reference is now made to the various figures.  FIGS. 1-4  are the multiple sheet feed system  2  with sheets in various stages of being shingle fed from a stack of sheets  4 . As shown in  FIGS. 1-4 , a cut sheet feeder  3  includes a stack of sheets  4  in a feed tray  5 . The stack of sheets  4  are urged by a spring-loaded mechanism  6  toward a singulator sheet drive system  8 . The singulator sheet drive system  8  is provided with an adjustable mechanism to feed a selected number of sheets from the stack of sheets  4 .  
         [0019]     The multiple sheet feed system  2  employs both overrunning dynamic clutch type rollers, hereinafter identified to by the letter “a” after the drawing reference number and overrunning static clutch type rollers, hereinafter identified to by the letter “b” after the drawing reference number. Various types of drive arrangements including dynamic and static drive arrangements may be employed in the system  2 , as for example the roller arrangements shown in  FIGS. 1   a  and  1   b.    
         [0020]     As shown in  FIG. 1   a , urge roller  28  is comprised of a roller  7  and an overrunning dynamic clutch  9  permitting the roller to be either on or off when the motor is active. The overrunning portion of the clutch permits the roller to turn when the material under it is under drive from an upstream roller lessening the drive force on the piece and reducing the possibility of tearing action on the piece as a result. A control signal on lead  23  determines whether the clutch is engaged or disengaged.  
         [0021]     As shown in  FIG. 1   b , drive roller  38  is comprised on a roller  17  and an overrunning static clutch  29 . The overrunning portion of the clutch permits the roller to turn when the material under it is under drive from an upstream roller lessening the drive force required to move the piece and reducing the possibility of tearing action on the piece as a result.  
         [0022]     Referring again to  FIGS. 1-4 , the sheet drive system  8  includes a pre-feed roller assembly  10   a  and a feed roller assembly  12   b . The pre-feed roller assembly  10   a  and feed roller assembly  12   b  are both controlled by a feed motor  14  and an associated control signal on lead  19 . A sheet of paper, such as cut sheet  15 , is fed by the pre-feed roller assembly  10   a  and feed roller assembly  12   b  to a separator station  16 . The separator station may be of any conventional number of separators, including a separator drive roller operating in conjunction with a separator stone or any other suitable mechanism for separating cut sheets.  
         [0023]     A thickness sensor  18  senses the thickness of sheet  15  at the separator station  16 . The sheet  15  is driven toward an arming nip consisting of an arming drive roller assembly  20   a  and an idler roller  22 . This clutch mechanism of drive roller assembly  20   a  functions to control the operation of the drive roller assembly  20   a  to control the number of sheets being fed to the take-away nip of drive roller assembly  24   b  and idler roller  26 . Drive roller assembly  24   b  operates to take away and move the various differing number of overlapping sheets from the sheet drive system  8 . The arming drive roller assembly  20   a  and take-away drive roller assembly  24   b  operate under control of the take-away drive motor  28  and associated a control signal on lead  25 . The arming drive roller assembly  20   a  is driven to rotate by take away motor  28 . The overrunning clutch of arming drive roller assembly  20   a  is controlled by the control signal on lead  25  to vary the drive torque applied by arming roller assembly  20   a  to drive the sheet(s).  
         [0024]     On piece initiation, the first sheet  15  is staged at the material sensor by turning on motors  14  and  28  and control signals on leads  19  and  25  until the first sheet is seen by material sensor  30 . At this point the feeder motor  14  and control signals  19  and  25  are turned off. The accumulator transport  37  is clear for the next piece to be assembled by gate  39  being activated to enable the previous accumulation to be moved out of transport  37 , and motor  14  as well as control signals on leads  19  and  25  turn on to begin assembly of the next piece with gate  39  again in the blocking position. The control signal on lead  19  is turned off once the end of the last sheet has passed by the roller (controlled by signals from thickness sensor and materials sensor  30 ). When the last piece has reached the arming roller assembly  20   a , motor  14  can be turned off.  
         [0025]     Once the last piece has reached takeaway roller assembly  24   b , the control signal on lead  25  can be turned off. When the end of the last sheet has passed take away roller assembly  24   b , motor  28  can be turned off. When the end of the last piece in the collation has passed the thickness sensor and sufficient interpiece gap has been generated, then motor  14  and the control signal on lead  19  can be turned back on to arm the first sheet of the next collation. This completes the cycle of piece assembly.  
         [0026]     The material sensor  30  is provided to sense the presence of material between the arming nip roller assembly  20   a  and idler roller  22  and the take-away nip formed by take away roller assembly  24   b  and idler roller  26 . An accumulator transport  37  is provided for transporting accumulated sheets  41 . An accumulator gate  39  is also provided to control transport of the accumulation  41 . The accumulator gate  39 , shown in the blocking position in  FIGS. 1 and 4 , is moveable in and out of the blocking position as denoted by line  43  with two arrowheads. The accumulator gate is shown in the non-blocking position in  FIGS. 2 and 3 .  
         [0027]     As is shown in  FIG. 2 , sheet  15  is shown as being fed with the pre-feed roller assembly  10   a  being now clear of the trailing edge of the sheet  15 . The pre-feed roller spring  11  drives the pre-feed roller assembly  10   a  down in the direction of the stack of sheets  4 , as shown in  FIGS. 3 and 4 . The pre-feed roller  10   a  engages a second sheet  32  ( FIG. 3 ) in the stack of sheets  4  to drive sheet  32  in the direction of the separator station  16 . As can be seen in  FIG. 3 , the thickness sensor  18  is sensing the thickness of two sheets, sheet  15  and sheet  32 . This is used to count the total number of sheet thickness that have been processed in order to control the operation of motors  14  and  28 , as well as the control signals on leads  19  and  25  to provide sufficient torque to drive one or more sheets through the system to the accumulator transport  37 , as shown in  FIG. 4 .  
         [0028]     The pre-feed roller assembly  10   a , as is shown in  FIG. 4 , is further urged to engage yet a third sheet  34  in the stack of sheets  4 . This begins to drive sheet  34  toward the separator station  16 . When the thickness sensor  18  senses the desired number of sheets at the separator station  16 , the drive of both pre-feed roller assembly  10   a  and feed roller assembly  12   b  are stopped by feed motor  14 . Accordingly, additional sheets are not fed from the stacks of sheets  4  toward the separator station  16  until the entire desired shingled group of sheets are moved away downstream for further processing toward the accumulator transport  37  and accumulator gate  39 , where a group of sheets  41  are aligned to form a single collation for further processing. The accumulator gate  39 , shown in the blocking position in  FIG. 4 , is moveable in and out of the blocking position as denoted by line  43  with two arrowheads. The further processing may include, for example, folding of the collation, insertion of the collation, binding of the collation and the like.  
         [0029]     The pre-feed roller assembly  10   a  and spring  11  are adjustable and are moveable. The pre-feed roller assembly  10   a  and spring  11  may be positioned to accommodate different length sheets and can be moved in either direction, as shown by line  36  with two arrowheads. The ability to selectively position the pre-feed roller  10   a  helps maximize the performance of the system  2  by accommodating stacks of sheets of differing lengths. Absent adjustment along line  36 , the pre-feed roller  10   a  would need to be positioned to accommodate the shortest length material that could be fed from the stack of sheets  4 . By making the pre-feed roller assembly  10   a  position adjustable, the performance of the system is maximized, depending upon the different lengths of material being fed. The force exerted by spring  11  may also be made adjustable. This accommodates different types of materials being fed, which may have different coefficients of friction between sheets within the stack  4 . These adjustments can greatly enhance the operation of the system  2 , where different lengths and types of media are to be processed by system  2 . Thus, for shorter type media in the stack, the pre-feed roller assembly  10   a  would be moved in the direction of the separator system  16 . For longer type media in the stack, the pre-feed roller assembly  10   a  would be moved in the direction away from the separator system  16 . The positioning of the pre-feed roller assembly  10   a  and spring  11  force is a matter of design choice and can be accomplished through trial and error until the optimum position is obtained.  
         [0030]     The prefeed roller assembly  10   a  and the feed roller assembly  12   b  are driven together by motor  14 , but the control signal on lead  19  permits turning off prefeed roller assembly  10   a  and continuing to drive with feed roller assembly  12   b . The arming nip roller assembly  20   a  and the takeaway roller assembly  24   b  can be either driven together or arming nip roller can be turned off using the control signal on lead  25  while continuing to drive with takeaway roller assembly  24   b , as is shown in  FIGS. 1-4 , or separately, depending on down stream requirements. The arm feeder commands can include commands to turn on the feed motor  14  until the leading edge of the sheet is at the thickness sensor  18 . A control stop command is provided when the sheet just reaches the arming nip formed by drive roller assembly  20   a  and idler roller  22 . The command may then be provided to wait for a feed command.  
         [0031]     The feeder commands can include commands to turn on the takeaway motor  28  and to turn on the feed motor  2 . A command is provided to monitor thickness sensor  18  for leading edge and trailing edge thickness changes until the last leading edge has been seen. A command may also be provided to delay feeding until the last leading edge is in the arming nip formed by drive roller  20   a  and idler roller  22 . A command is provided to turn off the feed motor  14  until thickness sensor  18  is clear of material. A command may also be provided to wait for a delay period and to arm the feeder.  
         [0032]     By using two or three motors and a single thickness sensor  18 , multiple sheets can be fed in an overlapped stream reducing the time needed to feed the sheets at any given drive speed. The larger the overlap the greater the gain in throughput. Also, the larger the number of sheets, the greater the gain in throughput. The accumulator transport  37  and gate  39  arrangement can realign the sheets, if desired, into a single aligned collation such as collation  41  shown in  FIG. 4 . The thickness sensor is used to detect lead and trail edges even when fully blocked by utilizing, for example, a burn through sensor such as ones used in the in the Pitney Bowes Inc. DI350 Officeright Inserting System. It may be desirable to limit the number of sheets that are under the thickness sensor  18  to two or less to improve the reliability of control. This may effectively limit allowable overlap to, for example, approximately 40%.  
         [0033]     Reference is now made to  FIG. 5 , showing the operation of the multiple sheet feed system  2 . The process starts at  40 . The motor  14  to drive feed roller assembly  12   b  is started at  42  and the pre-feed roller assembly  10   a  at  44 . A determination is made at decision block  48  whether a sheet has been singulated. If a sheet has not been singulated, the process goes to decision block  50 , where a determination is made if the process is timed out. If the process is not timed out, the system loops back to decision block  48 . If the process has timed out at decision block  50 , all active motors are stopped at block  58  and the process ends at  60 .  
         [0034]     Where a sheet has been singulated, the process continues to decision block  52 , where a determination is made whether the correct quantity of sheets have been reached by the thickness sensor  18 . Where the correct thickness has been reached, the process continues and the pre-feed motor is stopped at  54 . A determination is then made at decision block  56  whether the trailing edge of the sheet has been found. If this is the case, the process continues to block  58 , where all active motors are stopped. Since all of the material has passed the materials sensor  30  and the trailing edge has been found, the process stops at block  58  with all active motors stopped and the feed process ends at  60 .  
         [0035]     When a determination is made at decision block  52  that a correct quantity of sheets has not been reached by thickness sensor  18 , the process continues to decision block  50 . If the process has not timed out at decision block  50 , the process further loops back to decision block  48 . Where the trailing edge has not been found at decision block  56 , the process continues to decision block  62  to determine whether a trailing edge time-out has occurred. Where this has not occurred, the process loops back to decision block  56  and continues. However, where a trailing edge time-out has occurred at decision block  62 , the process continues to block  58  and all active motors are stopped and the feed process ends at  60 .  
         [0036]     Reference is now made to  FIG. 6 . The set up operation of the multiple sheet feed system  2  to implement set-up of the system is shown in  FIG. 6 . This enables the operation of the system shown in  FIG. 5 . The set-up operation of the multiple sheet feed system  2  starts at block  64 . At block  66 , a single item pre-fed trial item has the length and thickness of the item measured and also the drag force on the top sheet. At  68 , the singulation station  16  and gap shifts are set on the rollers, as well as the spring  11  tension of the pre-feed roller assembly  10   a . These operations may be implemented manually or automatically, based on the pre-feed measurements to optimize the performance of the multiple sheet feed system  2 . At  70 , the position and location of the pre-feed roller  10   a  is adjusted. This also may either be implemented manually or automatically, based on the system design. Finally, at  72 , a stream feed of a trial media item is implemented. The stream feed may also be automatically or manually initiated by the operator.  
         [0037]     While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Technology Category: b