Abstract:
An apparatus and method for producing a stack of documents, each having one or more pages, separated into documents. An input mechanism receives printed sheet material, which is cut by a cutter into document pages having a first dimension and flag sheets having a different dimension. A page laying unit stacks pages corresponding to a document in sequence and interposes flag sheets between successive documents. The direction in which the dimension of pages and flag sheets is different lies transverse to the direction of cutting.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This is the first application filed for the present invention.  
         TECHNICAL FIELD  
         [0002]    The invention relates to printing and in particular to an apparatus and method for producing a stack of documents that are easily identified and separated.  
         BACKGROUND OF THE INVENTION  
         [0003]    Retrieving printed documents from a stack of many printed documents often proves to be a difficult and error prone task. Determining where a multi-page document begins and ends in a stack of pages, identifying the individual documents that are stacked in an output tray and separating the desired document is a cumbersome task. The problem is exacerbated with the advent of print servers, in which a number of users may remotely direct a print job to a common server.  
           [0004]    In order to separate print jobs, whether or not sent from different sources, numerous approaches have been attempted. First, cover sheets may be automatically inserted between jobs. Such cover sheets, which have the same dimension as the page sheets, not only demonstrate the beginning (or end) of a print job, but also may identify the particular job by the text printed out on the cover sheet.  
           [0005]    Other approaches have been attempted to ensure that one document is separated from another. For example, the pages comprising a print job may be stapled together. However, the stapling process mutilates the pages of the document, which may not be desirable. Alternatively, successive documents may be stacked at a slightly offset from one another, so that a document may be easily identified. Typically, the output tray is configured to permit successive documents to be positioned at one of two offset positions, so that every second document has the same offset position. While this approach is effective for the purpose of separating out document in the output tray, once a document in the middle of the stack has been removed, the separation of the adjacent document will be lost. Other output trays provide more than two offset positions to avoid such difficulties, however, this introduces considerable additional mechanical complexity to the output path of the printer.  
           [0006]    There is therefore a need for a printing apparatus and method for producing a stack of documents that allows easy identification and separation of documents.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the invention to provide a printing apparatus and method for producing a stack of documents that are easily identified and separated into respective documents.  
           [0008]    Accordingly an apparatus is provided for stacking output of a printer. The apparatus comprises an input mechanism for receiving printed sheet material from the printer, a formatter for producing document pages and flag sheets, and a page laying unit for sequentially stacking pages and flag sheets to produce the stack of documents separated by flag sheets. The flag sheets have a different dimension than that of document pages, and thereby facilitate separation and/or identification of the documents.  
           [0009]    The input mechanism preferably comprises a feed mechanism for controlling reception of the printed sheet material from a printer at a cutter. The printer may be a laser-writing printer, and ink-jet printer or a dye-sublimation printer.  
           [0010]    The source of sheet material is preferably a web, and may consist of paper, film, metal, or cloth, that is cut to size by the cutter. The cutter preferably comprises means for cutting consisting of a blade that cuts the printed sheet material under tension, a laser cutter, or opposing blades for shearing the printed sheet material.  
           [0011]    Preferably the dimension of the flag sheet that is different than the respective dimension of the documents pages is in a direction transverse to a direction of cutting of the cutter.  
           [0012]    The page laying unit may be adapted to collate document pages, or sort document pages.  
           [0013]    Also according to the objects of the invention, there is provided a method for identifying pages corresponding to one or more documents from a stack of pages. The method involves receiving printed sheet material, separating the printed sheet material into groups of pages and introducing flag sheets having a different dimension than the corresponding dimension of the pages.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:  
         [0015]    [0015]FIG. 1 is a schematic diagram of a printing apparatus connected to a computer; and  
         [0016]    [0016]FIG. 2 is a schematic block diagram of the printing apparatus shown in FIG. 1. 
     
    
       [0017]    It should be noted that throughout the appended drawings, like features are identified by like reference numerals.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    [0018]FIG. 1 is a schematic diagram  100  of a computer  102  connected  104  to a printing apparatus  106 . The connection  104  may be a computer network such as an Ethernet implementation; a serial connection such as universal serial bus (USB) or IEEE 1394 cable; a parallel port connection; or a wireless connection such as Bluetooth or IEEE 802.11 lb. The computer  102  preferably includes a print manager  103 . A plurality of remote computers  110  (only one shown) may also be communicatively coupled to the computer  102  via a packet switching network such as the Internet  114 . Images (not shown)  110  may be transferred from the remote computer  110  via the Internet  114  to the print manager  103  in the computer  102 , or may originate in the computer  102 .  
         [0019]    [0019]FIG. 2 is a block diagram of a preferred embodiment of the printing apparatus  106  shown in FIG. 1. The printing apparatus  106  includes a source of sheet material  204  which is preferably a web  202 . The sheet material  204  may be, for example, paper, film, metal, or cloth. The printing apparatus  106  also includes a first feed mechanism  206  for feeding the sheet material  204  from the web  202  to a print engine  208  which may be, for example, a laser-writer or an ink-jet print engine.  
         [0020]    The print engine  208  prints images onto the sheet material  204 . The images may be, for example, two or three dimensional images; holographic images; text; or any combination thereof. The print engine  208  may print on either or both sides of the sheet material  204  to produce printed sheet material  212 . The printing apparatus  106  has a second feed mechanism  210  for feeding the printed sheet material  212  from the print engine  208  to a cutter  214 . The cutter  214  therefore includes a web input mechanism that includes the second feed mechanism  210  for receiving the printed sheet material from the print engine  208 .  
         [0021]    The cutter  214  cuts the printed sheet material  212  into sheets  218  of an appropriate size. The cutter  214  may constitute, for example, a blade, a laser or shearing mechanism.  
         [0022]    The printing apparatus  106  also has a third feed mechanism  216  for feeding the sheets  218  from the cutter  214  to a stacker  220 .  
         [0023]    The stacker  220  is an embodiment of a page laying unit adapted to lay the sheets  218  into a stack  222  of documents  224 . The stacker  220  may be, for example, a mechanism for sorting and/or collating documents; or a tray for receiving pre-sorted/pre-collated documents.  
         [0024]    The printing apparatus  106  may include a processor  230  coupled by connections  235 ,  246 ,  248 ,  250  to monitor or control other aspects of the printing apparatus  106 . For example, the processor  230  is coupled by connection  235  to sensor  260 , which senses a condition of the web  202 , such as a “source empty” condition. The processor  230  is coupled by connection  246  to the print engine  208 , whereby the processor  230  may transfer image data to the print engine  208 . The processor  230  is coupled by connection  248  to the cutter  214  for controlling the cutter  214  to cut the printed sheet material  212  into sheets  218  in accordance with available data and a predetermined program. Finally, the processor  230  is coupled by connection  250  to the stacker  220  for controlling the operation of stacker  220  or for sensing a condition of the stacker  220  such as a “tray full” condition.  
         [0025]    The printing apparatus  106  also includes a communication interface  232  coupled by a connection  234  to the processor  230  and adapted to communicate with the computer  102  (FIG. 1) via the connection  104 , whereby print job information is obtained from the computer  102 . The processor  230  is also coupled by a connection  238  to a keypad  236  for a user (not shown) to input commands to the processor  230 , and coupled by a connection  242  to a display  240  to permit the user to receive messages generated by the processor  230 .  
         [0026]    A memory  244  is also coupled to the processor  230  by a memory bus  252  for intermediate storage and processing of images received from the printer manager  103  (FIG. 1) via the connection  104  and the communication interface  232  before the image data is transferred to the print engine  208 .  
         [0027]    The sheets  218  produced by the cutter  214  may be of a first size, such as letter, legal or A 4 , referred to herein as pages; or a second size having a dimension, such as length or width, different from a corresponding dimension of the first size, referred to herein as flag sheets  226 . The dimension of the flag sheets  226  is preferably greater than the respective dimension of the pages.  
         [0028]    The flag sheets  226  separate the pages into logical groupings. An appropriate logical grouping may be a print job, a part of a document, or any other serial set of pages identified by a processor  230 . For convenience, such logical groupings are referred to herein collectively as documents  224 .  
         [0029]    The printing apparatus  106  produces the stack  222  of documents  224  that are partitioned by flag sheets  226  that facilitate identification and separation of individual documents in the stack  222  and reduce retrieval errors.  
         [0030]    Advantageously, the flag sheets  226  facilitate the identification and/or separation of the documents  224  by a user (not shown). It should be noted that the documents  224  may be copies, unique documents, or any combination of  226  may be identical to one another the two. Also, the flag sheets may have unique printed images to facilitate identifying individual documents  224 .  
         [0031]    Preferably, the shape of the pages in a document  224  or of the flag sheet  226  separating the documents  224  is rectangular.  
         [0032]    The use of flag sheets  226  having a different dimension than the corresponding dimension of the pages constituting a document  224  provides a mechanism for easily identifying where a document  224  begins and ends, without mutilating the pages of the document  224 , such as is the case with the use of staples. Additionally, the identification of where documents  224  remaining in a document stage  222  begin and end is maintained, even if a document  224  has been retrieved from the middle of the stack  222 .  
         [0033]    The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims. For example, it may not be strictly necessary for the printing apparatus  106  to use printed sheet material in a web, which material is cut to length by a cutter. Rather, the printed sheet material may be pre-cut and an appropriate size of printed sheet material used for both the document pages and for the flag sheets. For example, a document consisting of letter-sized pages may be separated by a flag sheet of legal-size dimension. In such a case, the identification of the separating flag sheets may be enhanced by using printed sheet material for the flag sheet having a different colour, texture, thickness or consistency than that used for the pages of the document.