Abstract:
A barcode scanning apparatus and method for reading barcodes on serially fed sheets having barcodes in a consistent location. A transport moves the barcode bearing sheets as they pass below at least two fixed barcode scanners. Both of a first and second barcode scanners scan the barcodes and transmit corresponding signals to an apparatus controller. Preferably the at least two barcode scanners are in series, one closely located immediately downstream of the other. The controller receives the signals from the first and second barcode scanners, and interprets them accordance with a predetermined algorithm. The predetermined algorithm is a function of both the first and second barcode signals and is selectable to provide different levels of reliability checking.

Description:
TECHNICAL FIELD 
   The present invention relates an apparatus and method for scanning barcodes on objects to be processed in an automated system, and in particular for a system used to process documents into finished mail pieces. 
   BACKGROUND OF THE INVENTION 
   Inserter systems, such as those applicable for use with the present invention, are typically used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Also, other organizations, such as direct mailers, use inserts for producing a large volume of generic mailings where the contents of each mail item are substantially identical for each addressee. Examples of such inserter systems are the 8 series, 9 series, and APS™ inserter systems available from Pitney Bowes Inc. of Stamford Conn. 
   In many respects, the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. Then, a variety of modules or workstations in the inserter system work cooperatively to process the sheets until a finished mail piece is produced. The exact configuration of each inserter system depends upon the needs of each particular customer or installation. 
   Typically, inserter systems prepare mail pieces by gathering collations of documents on a conveyor. The collations are then transported on the conveyor to an insertion station where they are automatically stuffed into envelopes. After being stuffed with the collations, the envelopes are removed from the insertion station for further processing. Such further processing may include automated closing and sealing the envelope flap, weighing the envelope, applying postage to the envelope, and finally sorting and stacking the envelopes. 
   Throughout the inserter system, documents are tracked, and automated processes are controlled, by scanning markings on the document sheets. The optical markings may be a series of dashes, or more sophisticated barcodes. As is known in the art, information contained in markings may include, but is not limited to, information identifying which mailpiece a sheet belongs to, how many sheets are in a mailpiece, what folds are to be made to the sheets, what inserts are to be included with the sheets, the weight of the mailpiece, and information about postage to be placed on the mailpiece. In a more sophisticated inserter system, a barcode may include a pointer to an electronically stored file that will include extensive information about the mailpiece and its processing, beyond what can be stored in the barcode itself. Optical scanning devices positioned group of sheets has reached a given location. Those same scanners can also read information from the sheet to initiate the appropriate processing on the sheet, or set of sheets, within the various modules. 
   The input stages of a typical inserter system are depicted in  FIG. 1 . At the input end of the inserter system, rolls or stacks of continuous printed documents, called a “web,” are fed into the inserter system by a web feeder  100 . The continuous web must be separated into individual document pages. This separation can be carried out by a web cutter  200  that cuts the continuous web into individual document pages. As an alternative to cutting a web, it is known to provide pre-cut sheets to the inserter system input. As the individual pages are created, a barcode on the pages is typically scanned for tracking their entry into the inserter system. Depending on the mail run specifications, the cutter  200  can be set to cut sheets of different sizes. For example, some mailings may require letter size sheets, while others might include legal sized pages, or smaller than letter sized pages. Downstream of the web cutter  200 , a right angle turn  300  may be used to reorient the documents, and/or to meet the inserter user&#39;s floor space requirements. 
   The cut pages must subsequently be accumulated into collations corresponding to the multi-page documents to be included in individual mail pieces. This gathering of related document pages occurs in the accumulator module  400  where individual pages are stacked on top of one another. 
   At the accumulator  400 , scanners sense markings on the individual pages to determine what pages are to be collated together in the accumulator module  400 . In a typical inserter application, mail pieces may include varying number of pages to be accumulated. When a document accumulation is complete, then the accumulation is discharged as a unit from the accumulator  400 . An accumulator module  400  should also be adjustable so that it is capable of handling sheet accumulations of different sizes. 
   Downstream of the accumulator  400 , a folder  500  typically folds the accumulation of documents to fit in the desired envelopes. To allow the same inserter system to be used with different sized mailings, the folder  500  can typically be adjusted to make different sized folds on different sized paper. As a result, an inserter system must be capable of handling different lengths of accumulated and folded documents. 
   Downstream of the folder  500 , a buffer transport  600  transports and stores accumulated and folded documents in series in preparation for transferring the documents to the synchronous inserter chassis  700 . By lining up a backlog of documents in the buffer  600 , the asynchronous nature of the upstream accumulator  400  will have less impact on the synchronous inserter chassis  700 . 
   On the inserter chassis  700  inserts are added to the folded accumulation prior to insertion into an envelope at a later module. Based on markings scanned from the accumulations, insert feeders are controlled to feed the appropriate inserts (for example advertisements, or special offers) to a particular mailpiece as they travel on the inserter chassis. 
   Thus it should be apparent that for accurate processing of documents, that it is important to accurately scan and read the markings on the documents. A known solution is to use a fixed beam scanner positioned to read barcodes as they are transported over it. If a fixed beam scanner is unable to read the barcode, because of poor barcode quality, or some other reason, the document cannot be correctly processed, and typically must be outsorted. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to increase accuracy for reading of barcodes, so that reliability is enhanced while outsorting and reprocessing of mailpieces is minimized in an inserter system. It has been found that a single fixed beam scanner works adequately when good quality barcodes are printed on the documents being processed. However, it is sometimes the case that poor quality barcodes are printed on the forms to be processed. With poor quality barcodes and high inserter speeds, a single fixed beam scanner arrangement may be insufficient for reliable processing. 
   One solution, not part of the present invention, could be to use a more expensive moving beam scanner in place of a fixed beam version. Moving beam scanners operate by moving a beam repeatedly across a barcode, and are known to be better at reading poor quality barcodes. However, in addition to being more expensive, moving beam scanners are much larger in size and can be difficult to correctly position without interfering with other mechanisms. 
   Accordingly, the present invention provides a barcode scanning apparatus that is less expensive and cumbersome than one having a moving beam scanner, and that more accurately reads barcodes than a single fixed beam scanner. In the preferred embodiment, the apparatus reads barcodes on serially fed sheets having barcodes in a consistent location. A transport moves the barcode bearing sheets below at least two fixed barcode scanners. Both a first and second barcode scanners scan the barcodes and transmit corresponding signals to an apparatus controller. Preferably, at least two barcode scanners are in series, with one located immediately downstream of the other. 
   The controller receives the signals from the first and second barcode scanners, and interprets them accordance with a predetermined algorithm. The predetermined algorithm is a function of both the first and second barcode signals, and is selectable to provide different levels of reliability checking. In this application, it should be understood that the term “signal” may include transducer signals from the sensors, or decoded data from the transducer signals, or both. 
   At a first level of reliability checking, the controller checks whether a first of the scanners has received a readable signal. If the signal is readable, then the controller controls processing of the document in accordance with the information scanned from the barcode. If the first signal is not readable, then the second scanner signal is checked to see if it is readable for that barcode. If the second signal is readable, then that signal is used for controlling the processing of the document. If neither signal is readable, then an error signal is generated, and corrective action is typically taken, such as outsorting the document from the production process. 
   A second level of reliability checking provides match comparison when available from the at least two fixed scanners. If both signals are readable, then a comparison is done between them. If there is not a match between the readable barcodes, then it is known that there has been a reading error from one of the scanners. Upon occurrence of such a mismatch, an error signal would be generated. If the signals match, then the documents is processed in accordance with the matched signals. 
   In the second level of checking, if only one of the barcode scanner signals was readable, then no matching is possible. Under this level of reliability, no matching is required, and processing proceeds using the single signal that was found to be readable. 
   Under the third level of reliability checking it is required that both barcode scanner signals be readable and that they both match. If either condition is not met under the third level of reliability, then an error signal is generated. 
   Further details of the present invention are provided in the accompanying drawings, detailed description and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram of the input stages of an inserter system for use with the present invention. 
       FIG. 2  depicts an isometric view of an improved inserter chassis utilizing a preferred embodiment. 
       FIG. 3  is a block diagram of a preferred embodiment of an inserter system using the barcode scanning apparatus and method. 
       FIG. 4  depicts exemplary barcodes on documents. 
       FIG. 5  depicts an exemplary defective barcode. 
       FIG. 6  depicts a flow diagram of a first preferred embodiment for processing of scan information. 
       FIG. 7  depicts a flow diagram of a second preferred embodiment for processing of scan information. 
       FIG. 8  depicts a flow diagram of a third preferred embodiment for processing of scan information. 
   

   DETAILED DESCRIPTION 
   In  FIG. 2 , a preferred embodiment for implementing the invention on an inserter system is depicted. Fixed barcode scanners  1  and  2  are positioned above a conveyor transport  15  on which documents  10  are transported. Pusher fingers  13  are driven by rotary belts (not shown) to drive sheets  10  in a downstream direction. Fingers  13  extend through slots  12  of transport arrangement  15  while sheets  10  are supported on a deck of the transport  15 . 
   Fixed barcode scanners  1  and  2  are preferably comprised of LED scanners  14  that are compact and easily positioned over the transport  15 . Scanners  14  may be any suitable scanning device, and may include scanners using infrared, or other portions of the optical spectrum. For the preferred embodiment, suitable scanners  14  can be obtained from DataLogic, Inc. of Hebron, Ky., or Optek Technologies Inc. of Carrollton, Tex. The scanning portions of fixed scanners  1  and  2  are positioned such that barcodes  11  on documents  10  pass below them for each document. The positions of barcodes  11  on the documents are predetermined so that the correct positioning of the scanners  1  and  2  is known in advance. 
   As seen in  FIG. 3 , fixed barcode scanners  1  and  2  are in communication with a controller  16  that controls processing of documents in the inserter system. As seen in  FIG. 3 , controller  16  controls, for example, a divert mechanism  17  for removing documents from the transport path of the inserter transport  15 . The diverter mechanism  17  is activated by controller  16 , for example, when scan data from fixed scanners  1  and  2  indicate that an error may have occurred. 
   It will be understood by one of ordinary skill in the art that scanners  1  and  2  include transducers that generate an electrical signal based on the presense or absence of a mark on the surface being scanned. This raw transducer information is then decoded for the applicable barcode type or font, and meaningful data is derived. For purposes of this application, it is not material whether the decoding process is carried out at the scanners  1  and  2 , or at the controller  16 . Herein, the term “signal” shall refer to the either of the raw transducer signal, or the decoded data, or both. 
     FIG. 4  illustrates two types of barcodes that are typically used in connection with processing of mailpieces on an inserter. Barcode  11   a  depicts an optical mark recognition (OMR) code. As is known in the art, the presence or absence of a line at a given location in the OMR mark has a predetermined meaning. For example, a bar at a certain location within the OMR mark may mean that a particular insert should be added to the mailpiece collation. The absence of that same OMR mark could mean that the particular insert should not be fed onto the collation. Barcode  11   b  is depicted as a more sophisticated kind of barcode having bars and spaces of varying thicknesses, and that is capable of containing more than the binary information in the OMR marks  11   a . Exemplary known barcodes of this type are Code  39 , Code  128 , interleaved 2 of 5, and UPC/EAN codes. 
     FIG. 5  depicts a flawed barcode  11  that includes a break along scan line  52 . Poor print quality would typically be the cause of the unwanted break, and could result in an inability of the apparatus to interpret the data in the barcode. As depicted in  FIG. 2 , the preferred embodiment utilizes fixed barcode scanners  1  and  2  arranged in series along the transport path of the documents. In an alternative embodiment, the barcode scanners  1  and  2  could be arranged side-by-side, so that, for example, scanner  1  could scan along line  51  and receive a good sensor reading, while scanner  2  could scan along line  52 , and receive the potentially defective sensor reading. In another alternative embodiment, the scanners  1  and  2  can be positioned diagonally from each other, whereby they are set apart in both the transport direction, and laterally to the transport direction. 
     FIGS. 6–8  depict flow diagrams for processing of signals from sensors  1  and  2  for providing enhanced reliability in the controller  16  for interpreting data and controlling document processing. Of the three figures, the process of  FIG. 6  provides the least level of enhanced reliability from using the two fixed barcode scanners  1  and  2 , while  FIGS. 7 and 8  depict increasingly enhanced reliability. 
   As seen in  FIG. 6  sensor signals  1  and  2  are received in steps  60  and  61 . At step  62 , the controller  16  determines if the sensor  1  signal is readable. If the sensor  1  signal is readable, then at step  63  the controller directs processing of the document in accordance with information derived from the sensor  1  signal. Once the document has been processed, then sensor signals are received once again at steps  60  and  61  for the next document to be processed. 
   If the sensor signal  1  was not readable at step  62 , then at step  64 , the controller determines whether sensor signal  2  is readable. If so, then at step  65 , the controller runs the apparatus to process the document in accordance with the sensor  2  signal. If neither signal  1  nor signal  2  is readable, then at step  66  the controller  16  generates an error signal. In the preferred embodiment, the error signal can result in activation of a diverter  17  to remove the problematic document from the transport  15  path. In an alternative embodiment, an error signal may result in a shut-down of the inserter system, or a secondary scanning system may be activated to perform further scanning operations. It will be understood by those skilled in the art that the error signal can be used to trigger any kind of response in the inserter system, and that the embodiments described above are exemplary in nature. 
   To achieve a higher level of reliability of scanned information, the process of  FIG. 7  provides for checking for matching between sensor signals  1  and  2 , when both are available. Sensor signals  1  and  2  are received in steps  70  and  71 . At step  72 , the controller  16  determines if both the sensor signals  1  and  2  are readable. At step  73 , if both signals are readable, then the controller  16  determines if the sensor signals  1  and  2  match. If there is a match then at step  74 , the controller  16  controls processing of the document in accordance with the matched signals. If the signals did not match, then at step  76  an error signal is generated. 
   Returning to step  72 , if both signals were not readable, then a determination is made at step  75  whether either signal is readable. If neither signal is readable, then an error signal is once again generated at step  76 . If one of the signals is readable, then at step  77  the document is processed in accordance with the readable signal. 
   Finally,  FIG. 8  depicts the highest level of reliability of the three examples shown in the figures. Sensor signals  1  and  2  are received in steps  80  and  81 . At step  82 , the controller  16  determines if both the sensor signals  1  and  2  are readable. If either or both signals are not readable, then an error signal is generated at step  85 . At step  83 , if both signals were readable, then the controller  16  determines if the sensor signals  1  and  2  match. If there is a match at step  83 , then at step  84 , the controller  16  controls processing of the document in accordance with the matched signals. If the signals did not match, then at step  85  an error signal is generated. 
   Although the invention has been described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and various other changes, omissions and deviations in the form and detail thereof may be made without departing from the spirit and scope of this invention.