Abstract:
A sheet processing system comprises a high speed printer operative to print sheets fed through the printer longer edge first, and a downstream processor for performing a subsequent operation using the printed sheet fed shorter edge first. A sheet feeder for feeding the sheet to the downstream processor with its shorter edge first, comprises a sheet feed conveyor extending to said downstream processor, and input feed means for feeding the sheet from the printer laterally onto the sheet conveyor so that the longer edges of the sheet extend in a longitudinal direction of the sheet feed conveyor. Guide surfaces ensure alignment of the longer edges of the sheet in the longitudinal direction of the sheet feed conveyor during feeding to the downstream processor.

Description:
BACKGROUND TO THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a sheet feeder, and more particularly to a sheet feeder for feeding sheets of paper from a printer to a downstream processor.  
           [0003]    2. Description of the Prior Art  
           [0004]    Certain processing machines for processing sheets, such as those for affixing credit/debit cards to sheets of paper, require A4 sheets of paper to be fed shorter-edge-first from a printer to the processing machine. These processing machines typically run at high speed, high volume, and require a suitably high speed, high volume, printer.  
           [0005]    However, most high speed, high volume, printers feed sheets longer-edge-first as this enables the printer to operate more quickly owing to the shorter edge of the page being quicker to feed through the printer than the longer edge. Accordingly, there are few high speed, high volume, printers available which feed sheets of paper shorter-edge-first, and those that are available are typically much more expensive than their longer-edge-first counterparts. Attempts to solve this problem have been made, one such attempt taking the approach of modifying software in the printer to enable the printer to feed shorter-edge-first, but this has not led to a satisfactory solution, and industry is still faced with the necessity of using the expensive high speed, high volume, shorter-edge-first printers.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, there is provided a sheet feeder for feeding a sheet from a printer to a downstream processor, said feeder serving to receive the sheet from the printer in a first direction and comprising first feed means for feeding the sheet to the downstream processor in a second direction, and alignment means for aligning the sheet in the second direction.  
           [0007]    Preferably, the sheet is rectangular with a longer edge and a shorter edge, the sheet is received from the printer longer-edge-first in the first direction, and is fed from the feeder to the downstream processor shorter-edge-first in the second direction, the second direction being substantially perpendicular to the first direction.  
           [0008]    Preferably, the first feed means is an endless belt and the alignment means includes a guide surface, and the sheet feeder further includes second feed means for moving the sheet longer-edge-first to a position in which the leading longer edge of the sheet abuts the guide surface.  
           [0009]    Preferably, the alignment means further includes a rail having a substantially vertical portion opposite the guide surface and a substantially horizontal portion, the rail being mounted substantially parallel to the belt in a raised position relative to the belt such that, during shorter-edge-first movement of the sheet, a trailing longer edge of the sheet adjacent the rail is curled upwardly to prevent or at least alleviate longitudinal buckling of the sheet.  
           [0010]    Further according to the invention, there is provided in a sheet processing system comprising a printer operative to print sheets fed through the printer in a direction transverse to the longitudinal axis of the sheet whereby the sheet is fed through the printer longer edge first, and a downstream processor for performing a subsequent operation using the printed sheet, the improvement comprising a sheet feeder for feeding the sheet to the downstream processor with a shorter edge first, said feeder comprising a sheet feed conveyor extending to said downstream processor, input feed means for feeding the sheet from the printer laterally onto the sheet conveyor so that the longer edges of the sheet extend in a longitudinal direction of the sheet feed conveyor, and means for ensuring alignment of the longer edges of the sheet in the longitudinal direction of the sheet feed conveyor during feeding to the downstream processor.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing, in which:  
         [0012]    [0012]FIG. 1 is a perspective view of a preferred embodiment of a paper feeder according to the present invention; and  
         [0013]    [0013]FIG. 2 shows schematically the manner in which the feeder is incorporated in a processing system including a printer and a downstream processor. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    The paper feeder  10  in accordance with the preferred embodiment of the invention includes a receiving means in the form of a receiving tray  12  for receiving a sheet  14  of paper from a printer P. In the particular embodiment shown, the sheet feeder  10  is configured to operate with sheets of A4 paper, however it should be noted that other embodiments of the sheet feeder may be configured to operate with sheets of other sizes and materials. The sheet feeder  10  is placed adjacent the printer P such that the longer edges  15 ,  16  of the A4 sheets  14  leaving the printer P are substantially parallel to a guide surface  18  of an alignment system of the sheet feeder  10  and such that the sheet  14  can be propelled (for example by means of the printer or gravity) to engage with at least one motor-driven roller  20  and to be sensed by a first sheet sensor  22 . In the embodiment shown, there are provided two spaced motor-driven rollers  20  which assist in keeping the longer edges  15 , 16  of the sheet  14  substantially parallel with the guide surface  18  throughout the longer-edge-first movement of the sheet  14  from the printer P. The first sheet sensor  22  is a photo cell of the infra-red type, having a beam-emitting portion mounted above the tray  12  and a beam-receiving portion mounted below the tray  12 . When a sheet  14  is detected by the first sheet sensor  22 , the motor-driven rollers  20  are operated to drive the sheet  14  in a first direction (indicated by arrows  24 ) toward the guide surface  18 . A delay may be incorporated into the control system of the motor-driven rollers  20  to operate the rollers  20  for a short period of time after the sheet  14  has travelled past the first sheet sensor  22 . This delay ensures that the leading longer edge  15  of the sheet  14  will reach the guide surface  18 . The applicant has also determined that it would be possible for the motor-driven rollers  20  to run continuously, however this would consume power unnecessarily and would result in excessive wear of the motor  28 . Each of the motor-driven rollers  20  is associated with a corresponding sprung roller  30  mounted beneath the motor-driven roller  20  for ensuring contact between the sheet  14  and the motor-driven roller  20  and thereby ensuring reliable operation.  
         [0015]    Reliable operation of the sheet feeder  10  is particularly important when the sheet feeder  10  is used in conjunction with a downstream processing machine M for applying credit/debit cards to sheets of paper as the sheets being received by the printer may be unique, and may thus have a corresponding credit/debit card awaiting to be applied to the sheet in the downstream processing machine. Accordingly, if a unique sheet is not reliably handled by the sheet feeder  10 , for example if proper engagement between the motor  15  driven rollers  20  and the sheet  14  is not achieved, the sheet  14  may be moved in a skewed manner and may be damaged rendering it unusable, and the sequence of the downstream processing may be upset.  
         [0016]    The sheet  14  is propelled by the motor-driven rollers  20  across a main feed belt  32 , such that the leading longer edge  15  of the sheet  14  abuts the guide surface  18 . The belt  32  is endless and moves in a second direction (indicated by arrow  34 ) which is substantially perpendicular to the first direction  24 , the belt  32  having a downstream end positioned to discharge the sheet  14  to the intake zone of the downstream processor M. The belt  32  is of a material which allows the sheet  14  fed by the rollers  20  to slide freely across the surface of the belt. By way of example, the belt  32  can be formed of polyurethane. The belt  32  is formed with sets of lateral flights  35  spaced lengthwise along the belt by a distance greater than the length dimension of the sheet  14  so that movement of the sheet  14  by the belt  32  occurs by engagement of a set of flights  35  with the trailing end of the sheet  14 .  
         [0017]    In operation, just prior to the leading longer edge  15  of the sheet  14  abutting the guide surface  18 , the sheet  14  is detected by a second sheet sensor  38  which, as with the first sheet sensor  22 , is preferably of infra-red type. When a sheet is detected by the second sheet sensor  38 , after a short delay which allows the sheet to settle against the guide surface  18  (as there may be some ‘bounce’ of the sheet  14  off the guide surface  18 ), the main feed belt  32  is operated to feed the sheet  14  in the direction of arrows  34  by engagement with its adjacent set of flights  35  with the trailing edge of the sheet.  
         [0018]    In the embodiment illustrated, the alignment system for ensuring alignment of the sheet  14  in the direction of travel  34  of the belt  32  includes the guide surface  18  and other guide surfaces as will be described. The guide surface  18  consists of a substantially vertical wall against which the leading longer edge  15  of the sheet  14  abuts, and which is made of a suitably smooth material such as stainless steel which allows the sheet  14  to slide along the guide surface  18  when being moved in the second direction  34 . The alignment system also includes an L-shaped rail  42 , for example of aluminium, mounted opposite a downstream portion of the guide surface  18 , the L-shaped rail  42  having a substantially horizontal portion  44  and a substantially vertical portion  46 . The guide surface  18  and the L-shaped rail  42  are mounted apart by a distance only marginally greater than the length of the shorter edge  48  of the sheet  14 , as this assists alignment of the sheet  14  and prevents jamming. The rail  42  is mounted in a position slightly above the level of the belt  32  so that when the sheet  14  rests between the guide surface  18  and the vertical portion  46  of the rail  42 , the opposite longer edge  16  of the sheet  14  adjacent the vertical portion  46  of the rail  42  rests on the substantially horizontal portion  44  of the rail  42  and is curled upwardly thus giving the sheet  14  increased longitudinal rigidity to reduce buckling of the sheet  14  during its movement in the second direction  34 , curling of the sheet  14  being ensured by gravity rollers  52  pivotally mounted above the belt  32  adjacent the downstream end thereof, and exerting pressure against the upper surface of the sheet  14  under their own weight to ensure contact between the belt  32  and the sheet  14 . If necessary, a further set of gravity rollers can be mounted upstream of the rollers  52  to ensure that contact is maintained between the sheet  14  and the belt.  
         [0019]    When the sheet  14  reaches the downstream end of the belt  32  and is discharged onto the upstream end of the downstream processor M, for example onto an intake conveyor belt or onto intake conveyor rollers of the processor, the belt  32  is stopped in a position in which the next set of conveyor flights  35  is positioned to engage the trailing edge of the subsequent sheet  14  fed from the printer P. In the embodiment shown this is achieved by a sensor  60 , preferably an infra-red sensor, which senses a reflective zone  62  on the belt  32  adjacent each set of flights  35 . Alternatively, stopping of the belt  32  in a position to receive the subsequent sheet  14  can be effected by other means such as sensing the position of the sheet  14  already at the downstream end of the belt  32 .  
         [0020]    To ensure correct synchronism of operation of the printer P with the operation of the downstream processor M, the printer P operates “on demand” according to the operation of the downstream processor M. The control system between the downstream processor M and the printer P to achieve this will be well known per se to persons skilled in the art and does not form part of the present invention. However in determining the speed and operative length of the belt  32 , account must be taken of the likely maximum output of the printer P (in terms of sheets per unit time) to ensure that successive sheets are not in interfering relationship on the belt  32 . By way of example, the printer P may have a maximum output of 40 sheets per minute with the feeder  10  being designed to cope with that feed rate although, in practice, as the printer P operates “on demand” in accordance with the requirements of the downstream processor M it is likely to operate at an average output somewhat less than that figure.  
         [0021]    Although the downstream processor M discussed above is a machine for applying credit/debit cards to sheets of paper, the present invention is equally useful in conjunction with other processing machinery requiring shorter-edge-first in-feed, for example, machines for applying other types of cards to sheets, and paper folding machines.  
         [0022]    The sheet feeder  10  is also provided with a counter  64  activated by the second sheet sensor  38 , to count the number of sheets passing through the sheet feeder.  
         [0023]    A prototype of the sheet feeder has been tested and is capable of feeding A4 sheets at a rate greater than is provided by a typical longer-edge-first high speed, high volume, printer. The speed of the sheet feeder may be increased by increasing the speed of the belt  32  and/or the speed of the motor-driven rollers  20 .  
         [0024]    The present invention provides an inexpensive alternative to shorter-edge-first high speed, high volume, printers. It also provides those requiring shorter-edge-first in-feed to a downstream processor with a much greater choice of printers. The sheet feeder delivers paper with improved alignment, and as the paper is fed through a right-angle change in direction, the printer is located to the side of the sheet feeder rather than being in-line with the downstream processor resulting in a more convenient usage of space.  
         [0025]    The applicant has foreseen that the present invention would be useful not only in applications requiring the re-orientation of rectangular paper for the sake of shorter-edge-first feeding, but also to those applications requiring the re-orientation of sheets in general, as the sheet may have to be re-oriented for some reason unrelated to the shape of the sheet. For example, the sheet may have to be re-oriented owing to the orientation of an image on the sheet or perhaps some orientation-dependent property of the sheet.  
         [0026]    The embodiment has been described by way of example only and modifications are possible within the scope of the invention. In particular, it should be noted that other suitable types of sensors may be used in place of the infra-red photo cell sensors, and instead feeding the sheet by flights on the belt, the belt may act in conjunction with one or more rollers which maintain the sheet in driving contact with the belt to ensure reliability of feed, or alternatively the belt may be associated with a suction system which maintains the sheet in driving contact with the belt.