Patent Publication Number: US-2007097447-A1

Title: Sheet handling device and process

Description:
This application is a continuation-in-part of my co-pending application Ser. No. 11/189,813, filed Jul. 27, 2005. 
    
    
     FIELD OF THE INVENTION  
      This invention relates to a device and process for handling printed sheets leaving digital sheet printers, able to be directly connected in line with the printer to obtain an integrated system for printing sheets of various formats containing several single-page or multiple-page documents, and their conversion into documents by cutting them transversely to the sheet movement direction and by other operations subsequent to the transverse cut.  
      The handling device and process are applicable both to digital sheet printers in which the paper moves from right to left in the printer and to digital sheet printers in which the paper moves from left to right in the printer.  
     BACKGROUND OF THE INVENTION  
      In the state of the art, those offices and departments using industrial digital printers for sheets, for example for printing employee&#39;s pay-packets, print on sheets of A4 format which, after printing, are sorted, then stacked in vertical receivers and subsequently inserted into a machine for envelope filling or for binding.  
      Currently, the printing cost is dependent not on the size of the printed sheet but on their number, hence for those offices which process large document quantities, the total printing costs are proportional to the quantity of sheets handled by the printers.  
     DISCUSSION OF THE RELATED ART  
      It is very common to use industrial digital sheet printers to print documents consisting of several A4 sheets with sheet quantities variable between one document and the next in their printing sequence. Whatever their format, the printed sheets are commonly collected in receivers which stack the sheets vertically by laying them extended one on another. In order not to interrupt the printing process, when a first vertical receiver is full the A4 sheets are fed to a second vertical receiver via a bypass device of the first vertical receiver.  
      With current printing programs commonly used for printers, it is never possible to ensure that all the documents of variable sheet quantities are completely collected in the first vertical receiver, so that it can happen that a document has part of its sheets collected in the top of the pile of the first vertical receiver and part of its sheets in the bottom of the pile of the second receiver.  
      For subsequent post-print handling of the documents, whether envelope filling or binding, the documents have to be worked while maintaining them in the sequence in which they were printed.  
      If the machines used for envelope filling or binding were to handle the piles of sheets of the vertically collected documents as extracted by the printers which withdraw the sheets from the top of the pile, the document printing sequence would be altered and there would be the risk of not being able to complete document processing where part of the sheets have finished at the bottom of the first row of the first vertical receiver and the remaining sheets of the same document have finished at the bottom of the pile of the next vertical receiver.  
      The solution universally used consists of manually unloading the sheets from the various vertical receivers of the printers, taking care that the document print sequence is maintained when loading the sheets onto the sheet feeders of the envelope or binding machines. This manual procedure implies risks of error in the post-print processing stages besides a general productivity loss in the entire document processing, printing and distribution procedure.  
      With usual print cost debiting mechanisms based on the “click charge” concept, the cost of printing an A3 sheet is the same as the cost of printing an A4 sheet, hence the user of digital printers for sheets could print A4 page documents on A3 sheets, collect them in the usually used vertical receivers and, before passing to subsequent envelope filling or binding, divide the pile of A3 sheets into two piles of A4 sheets using industrial guillotines. However this procedure would not be practicable because all control over the sheet sequence in the documents would be completely lost.  
      Similar considerations also apply to sheet formats other than A4 and A3.  
     SUMMARY OF THE INVENTION  
      An object of the present invention is therefore to provide a device and process which overcome the aforesaid drawbacks.  
      A particular object is to reduce the print costs and times by printing documents on A3 sheets, forming coherent A4 documents by cutting each A3 sheet along its short side, and collecting the documents in A4 format.  
      A further object is to simplify the feed of sheets to the envelope or binding machine by providing a process for collecting A4 documents on horizontal receivers insertable into the printing machine, which maintain the sheets in a vertical position and in the correct print sequence even if the collection of a document print flow is divided between two or more horizontal receivers.  
      A further object of the invention is to provide a device connectable directly to digital sheet printers upstream and to other devices and/or machines downstream of the device itself, to allow post-print operations and processes which are very flexible while at the same time enabling the digital printers to totally utilize their printing versatility towards a plurality of applications in the most varied sectors in which digital printing is used.  
      In particular, according to the invention the sheets being handled (of A3 or other than A3 format) can be cut in various ways for their conversion into documents (of A4 or other than A4 format) or the cutting step can be bypassed and the documents (i.e. the cut sheets) be collected differently according to specific requirements.  
      Another object of the invention is to provide a device and process adaptable to the downstream processes and machines.  
      For example, according to the invention the documents are collected in piles, the flow of these document piles being adaptable to the characteristics of the printer (which for example may not be able to accommodate frequent successive stoppages and starts) and/or to the specific needs of the downstream machines or processes which, for example, may require the sheets to be fed in a specific direction or in a predetermined manner.  
      These and further objects are attained according to the present invention by a device and process in accordance with the accompanying claims.  
      The reference to A3 and A4 formats is given by way of example only, similar considerations and advantages also applying to formats other than A3 and A4. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Further characteristics and advantages of the invention will be more apparent from the ensuing description of a preferred but non-exclusive embodiment of the device and process of the invention, illustrated by way of non-limiting example in the accompanying drawings, in which:  
       FIG. 1  shows a preferred embodiment of the device according to the invention;  
       FIGS. 2-5  are schematic views showing different embodiments of the process;  
       FIG. 6  is a schematic view of a device according to the present invention;  
       FIGS. 7 and 8  show two embodiments of the invention associated with document finishing machines; and  
       FIGS. 9A-9F  show an example of the implementation of the process of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Current printers are controlled electronically and can print on either A4 sheets or A3 sheets, distributing the print on the sheets in the manner desired by the user.  
       FIG. 1  shows a preferred embodiment of the device of the invention, comprising a cutting member  1  for cutting the A3 sheets A originating from a digital sheet printer (not shown) able to print on both A3 and A4 sheets, to produce from each A3 sheet two (or more than two) A4 sheets B, a conveying member  2  for the sheets, a control member  3  able to distribute the sheets by moving them to the right or left, depending on the desired collecting process, towards one or more horizontal removable receivers  4 ,  5  which stack the sheets vertically and are to be used as loaders for one or more manipulator machines, for example an envelope machine  6  or binding machine  7 .  
      In an alternative configuration the sheets can be stacked horizontally by resting them one on the other on their faces.  
      The sheet handling device of the invention operates connected directly to the digital sheet printer, i.e. the printed sheets are directly fed to the device and handled in such a manner as to obtain a single process from printing to the finished document, i.e. without continuous production of complex documents.  
      The same control member  3  is able to feed the sheets cut into A4 format to two interceptor and receiver devices  8  and  9  should any irregularities occur while printing the sheets or reducing the sheets from A3 format to A4 format. Depending on the requirements of the subsequent post-print process, the sheets converted into A4 format can be stacked vertically resting either on their short side or on their long side. The receivers comprise a sheet carrier belt and a movable wall ensuring that the sheets are compacted, hence enabling them to be stacked vertically on the horizontal receivers while maintaining the correct print sequence.  
      The text which is to be carried on two A4 sheets is printed on one A3 sheet, resulting in both a reduction in cost, which is calculated on the basis of the number of sheets printed independently of their dimensions, and a reduction in time due to the elimination of the time required for feeding a double quantity of A4 sheets to the printer.  
      The A3 sheet is then cut into two A4 parts by a cutting member  1  fed by a conveying member  2 .  
      After the printing and cutting operation, the resultant A4 sheets are inserted into a control member  3 , able to shift the sheets towards the right or left, to distribute them to suitable receivers  4  and  5 . These horizontal receivers  4  and  5  in which the sheets are vertically stacked, are preferably of horizontal stacking type and present the characteristic of being removable and usable as loaders for envelope machines  6  or binding machines  7 . This characteristic is particularly advantageous because it enables the sheets to be inserted into the envelope machines  6  and binding machines  7  in the order in which they were printed.  
       FIG. 1  shows an example of a printer from which the A3 sheets are expelled along a direction from right to left, however it is apparent that the same concepts apply if the sheets are expelled along other directions, and in particular from left to right.  
       FIGS. 2-8  show further embodiments of the device of the invention.  
      In these embodiments the device  10  comprises a printer connection module for transporting sheets  13  with registration  12 , which receives said sheets  13  from an industrial digital sheet printer  14  and feeds them to a cutter  15  (for example of rectilinear blade and counter-blade type with electronically controlled reciprocating movement) which transversely cuts (at 90° to the direction in which the sheets originating from the printer move) the sheets  13  and generates two or more documents  13   a ,  13   b  (in this description the term “document” means any sheet part which is cut, such documents  13   a ,  13   b  being able to be combined to generate complex documents comprising a plurality of pages).  
      From the latter (cutter  15 ) the documents  13   a ,  13   b  are fed to a receiver  17  which receives them, stacks them while maintaining their print sequence and transfers them to a discharge device  18 .  
      The receiver  17  stacks the documents  13   a ,  13   b  horizontally face to face and maintained in the sequence in which they were printed; this is shown in  FIG. 6  which shows three piles  19  of documents.  
      The cutter  15  cuts the sheets  13  into two or more parts to form documents  13   a ,  13   b  of equal or different dimensions; in particular,  FIG. 2  shows an embodiment in which each sheet  13  is cut to form two equal documents  13   a ,  13   b.    
      The documents can be stacked into a single pile  19  ( FIG. 2 ), however in other examples the receiver  17  is arranged to stack the documents into two or more piles  19 .  
      The documents  13   a  are all stacked into a first pile and the documents  13   b  are all stacked into a second pile or, alternatively, the documents  13   a  and  13   b  are all superposed into a single pile then, when this has reached the set limit, all the parts  13   a ,  13   b  are stacked into another pile.  
      The discharge device  18  is arranged to feed the document piles in a direction aligned to the direction in which the documents  13  advance during processing or, alternatively, in a direction inclined, preferably by 90°, to the direction in which they advance during processing; this is shown by the arrow F of  FIG. 7 .  
      The device  10  comprises control means  21  interfaced with the printer  14  positioned upstream of the printer connection module for transport with registration  12 ; these control means  21  implement the offset function in the receiver  17  as shown in  FIG. 3 , in addition to controlling devices of the printer and of the device  10  to facilitate restoration of the automatic cycle after possible errors in both machines and to ensure integrity of the converted documents.  
      The piles of superposed documents  13   a ,  13   b  can also be fed automatically to a finishing machine  20  to implement an automatic document forming system which starting with blank or pre-printed documents enables printed documents possibly composed of several bound pages to be obtained.  
      In this case a conveyor is preferably provided downstream of the device  10  (after cutting by the cutter  15 ) to feed an automatic booklet former of type CEM series CSG ( FIG. 8 ).  
      The device  10  can also comprise a trimming device  23  with one or more pairs of circular blades, to longitudinally trim the documents  13   a ,  13   b  already cut by the cutter  15 ; this trimming device  23  is interposed between the cutter  15  and the receiver  17 .  
      Advantageously the device  10  comprises a longitudinal cutting device  25  for example of circular blade type, to cut the documents  13   a ,  13   b  along a longitudinal direction (in the direction in which the sheets move through the printer); the longitudinal cutting device  25  is also positioned between the cutter  15  and the receiver  17 .  
      Advantageously, this embodiment of the device enables a continuous sheet flow to be achieved from the printer to the finishing devices by uninterruptedly forming packs of sheets and distributing them. These sheet packs are directed in the direction in which the paper flows or in a direction perpendicular thereto.  
      This embodiment is particularly suitable for satisfying book-on-demand requirements.  
      A member for intercepting and discarding defective sheets is also suitably provided (not shown), to ensure the quality of the documents produced; this device is of a type known to the expert of the art. The member is integrated into the device  10  and is positioned between the exit of the cutter  15  and the receiver  17  and comprises an intermediate collection station enabling the converted documents to be accumulated during pile discharge and offset in order not to have to temporarily halt the printer, hence allowing uninterrupted operation.  
      The control means  21  control the device operation and are arranged to implement bypassing of the cutter  15 , to enable the sheets  13  to pass through the cutter without being cut into parts of smaller dimensions and hence be fed to the downstream processing unit without being stacked, by an additional conveyor device. Alternatively these uncut sheets can be fed to the stacking system by the already described methods.  
      The control means  21  enable the device to receive commands from the printer  14  and to feed the printer with data enabling the device and printer to operate in a coherent manner, including the error situations which can arise in both machines. The control means  21  can also be provided with systems for sensing control codes printed on the sheets by the printer to enable control and/or mechanical operations on the documents to be carried out.  
      With particular reference to those embodiments of the invention shown in  FIGS. 2-8 , the operation of the device is apparent from that described and illustrated, and is substantially as follows.  
      The printer  14  prints the desired information on the sheets  13 .  
      For example the sheets are of A3 dimensions, the information being printed (by the digital sheet printer) on each half of the A3 sheet.  
      The sheets  13  are then fed, by the printer connection module for transport with registration  12 , to the cutter  15  which transversely cuts the A3 sheets into two A4 sheets which are stacked by the receiver  17 .  
      Stacking can take place by one of the previously indicated methods.  
      If the documents have to be further cut (for example to form documents of A5 size) the longitudinal cutting device  25  is also operated and the documents  13   a ,  13   b  are further cut longitudinally to obtain documents of the desired format.  
      The documents must be correctly printed on the sheet  13  fed to the printer, the subsequent cutting steps then separating each document from the others printed on the same sheet; this operation is executed flexibly and rapidly by the device of the invention.  
      The present invention also relates to a sheet handling process consisting of cutting the sheets  13  to separate documents  13   a ,  13   b , collecting the cut documents  13   a ,  13   b  and stacking them to form the finished document.  
      In particular, the following steps are performed: 
          printing the text intended for two documents of A4 format onto a single sheet of A3 format;     cutting the A3 sheet into two A4 sheets;     distributing the A4 sheets to various removable horizontal receivers  4 ,  5  with vertical or horizontal stacking of the A4 sheets and with maintenance of the correct print sequence, or possible discarding of any blank or badly printed sheets;     intercepting and collecting sheets which are not to be fed to subsequent post-print operations.        

      In a particular embodiment of the process of the invention, the following steps are also provided: 
          disconnecting the removable receivers from the printer and connecting them to suitable envelope machines and/or binding machines;     withdrawing the A4 sheets in succession by the envelope machines and/or binding machines.        

      Preferably, according to the invention the documents  13   a ,  13   b  are collected by stacking them horizontally face to face while maintaining the print sequence, with continuous production of complex documents.  
      The sheets are divided into two or more documents of equal or different dimensions and are stacked into a number of piles.  
      In a first example of the process, after cutting, each of the documents  13   a ,  13   b  is stacked on a different pile. Thus enables reduced dimension documents to be printed, such as cheques or other documents, on sheets which can contain two columns of them, each column containing multiple names. By means of the invention two document piles are created, one for each of the two print columns, the documents of each pile being grouped on the basis of identical multiple names by the offset function, ready to pass to the subsequent post-print operations. A typical example is the processing of cheques or other documents to be formed into booklets by finishing machines not integrated with printers.  
      In another example, after cutting, all the documents  13   a ,  13   b  are stacked onto one and the same pile.  
      When necessary, as shown in  FIG. 3 , the documents  13   a ,  13   b  are stacked by implementing the offset function. This can also be done by adjusting the spread set for the documents (i.e. the dimension d) in accordance with preset parameters and in relation to the printer commands related to the sheets being printed.  
      According to the process the cutting step can be bypassed, to obtain at discharge not only documents with smaller dimensions than those of the initial sheets because they have been converted into documents of the required dimensions, but also documents with the initial dimensions.  
      According to the invention the stacking operation can also be bypassed, both for sheets on which the conversion cut is not made and also for documents resulting from conversion by single or multiple cutting of the printed sheets. This enables sheets or documents to be fed to other post-print handling systems integrated with the printer while maintaining the device of the invention interposed and operating, ready at any moment to easily pass to other applications for which its main functions are required. The conversion cutting bypass and the stacking bypass functions, if associated with a configuration of the conveying device by which the document piles are conveyed in a direction at 90° to the paper flow, give an exceptional degree of flexibility and versatility to an automatic post-print finishing system completely integrated with the printers.  
       FIGS. 9A-9F  show a further example of implementation of the process of the invention particularly suitable for satisfying the book-on-demand market, in which runs of even a single title (i.e. a single volume) are printed in digital format.  
      In this respect, a plurality of documents  31 ,  32 ,  33 ,  34 ,  35 ,  36  are printed on a single sheet  30  ( FIG. 9A ).  
      The transverse cuts  37  ( FIG. 9B ) and the longitudinal or trimming cuts  38  ( FIG. 9C ) are then made to separate from one another the documents  31 - 36  ( FIG. 9D ).  
      Finally the documents  31 - 36  are superposed on each other ( FIG. 9E ) in a prearranged scheme depending on the printing method, to form the finished complex document  40  ( FIG. 9F ).  
      This is achieved by transferring the individual documents  31 - 36  from left to right or from right to left, according to the print sequence, to mutually superpose them in their exact print sequence by a known device of the type described in IT 1 244 770.  
      In this manner piles can be formed consisting of a single complex document (book or volume), to satisfy the book-on-demand sector for one-off books.  
      This is particularly advantageous because the market tendency indicates that in the digital book printing sector the run make-up now tends towards a single example per run.  
      Advantageously, with the process of the present invention, runs subsequent to the first can be produced, each consisting of a single complex document (evidently, this is also true for the first run); in other words, those runs subsequent to the first (and also the first run) can comprise even a single volume or book.  
      In practice, printing is carried out such that the document J (i.e. page J) is superposed on the other documents to form the Jth document (i.e. the Jth page) of the complex document (i.e. the book or volume).  
      It has been found in practice that the device and process of the invention are particularly advantageous because they enable documents to be formed in a vary flexible and economically convenient manner, even for very small print runs.  
      The device and process conceived in this manner, although applicable to all digital sheet printers of industrial type of currently known handlable format and printing speed, are susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover all details can be replaced by technically equivalent elements.  
      In practice the materials used and the dimensions can be chosen at will according to requirements and to the state of the art.