Patent Publication Number: US-2022219203-A1

Title: Document Imaging System and Method for Imaging Documents

Description:
RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 16/285,075 filed Feb. 25, 2019, which claims priority to U.S. Provisional Patent Application No. 62/634,723 filed on Feb. 23, 2018. This application also claims priority to U.S. Provisional Patent Application No. 62/842,842 filed on May 3, 2019. The entire disclosure of each of the foregoing applications is hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of document processing. In particular, the present application relates to processing documents to feeding documents to a device for further processing of the documents. The present invention finds particular application to the field of document imaging in which documents are to be fed to an imaging system, such as a document scanner. 
     BACKGROUND 
     Automated and semi-automated machines have been employed for processing documents. There have been numerous improvements in the field of document processing, including scanning and sorting documents, such as incoming mail. However, there remains a dsire to improve the handling and processing of documents. 
     SUMMARY OF THE INVENTION 
     The present system provides a number of improvements in the fields of document processing, including separate inventions in document handling, document scanning, and processing incoming mail. Although each of these improvements are combined into a single system, each of the improvements may be used as a separate invention in a document processing system. 
     For instance, according to a first aspect, a system is provided having a scanner for scanning documents, such as incoming envelopes, to obtain image data for the scanned documents. The image data may then be exported to await instructions from a separate user to provide instructions for how the documents are to be processed further. The system further includes a separate scanning element for detecting a marking or other identifying indicia on the documents for identifying the documents during a subsequent scan after the instructions have been received so that the instructions can be correlated with the document so that the document can be processed in accordance with the instructions. 
     According to another aspect, the system provides a system for processing documents that includes a conveyor for receiving documents, a plurality of output locations configured to receive documents from the conveyor and a sorter for sorting documents to the output locations. Optionally, the conveyor may be configured to convey documents along a document path without entraining the documents. Optionally, the sorter includes a first set of ejectors for displacing the documents transverse the document path. The sorter may optionally include a displaceable stop operable to selectively stop documents along the document path. Additionally, the sorter may optionally include a pair of rotatable cams and a pair of rotatable cam followers connected with one or more of the first set of ejectors and the stop to selectively control the ejector and the stop. Optionally, the sorter may include a shaft connected with the first and second cams such that rotation of the shaft by a first angular amount raises the stop without raising the ejector and wherein rotation of the shaft by a second amount raises the ejector. 
     According to another aspect, the present invention provides a document processing apparatus having a first conveyor having a first adjustment mechanism. The apparatus also includes a second conveyor operably connected with the first conveyor so that documents discharged from the first conveyor are fed onto the second conveyor without manual intervention. The system further includes a sensor for detecting a characteristic of the first conveyor that is indicative of the height of the first conveyor. The second conveyor includes a second adjustment mechanism for adjusting the height of the second conveyor, wherein the second adjustment mechanism automatically adjusts the height of the second conveyor in response to signals received from the sensor. 
     According to a further aspect, the present invention provides an apparatus for processing documents that includes a scanner, a conveyor and a printer assembly. The printer assembly is configured to maintain the print head in operative engagement with the documents while documents of varying thickness pass by the printer assembly. Optionally, the printer is an ink jet printer having a print head and a linkage interconnects the print head with a follower positioned adjacent the conveyor. The documents may pass between the conveyor and the follower so that the follower is vertically displaceable in response to changes in thickness of documents. Optionally, the linkage transfers vertical displacement of the follower to vertical displacement of the print head. 
     According to yet another aspect, the present invention provides a document receptacle configured to accept a variety of documents and to minimize overlapping documents that can lead to documents jamming. In particular, the receptacle may be configured to receive documents being conveyed in a generally horizontal orientation. Optionally, the receptacle has a first edge adjacent a paper path, such as a conveyor and a second edge opposing the first edge and spaced apart from the first edge. A substantially horizontal land in disposed between the first edge and the second edge. A first bottom surface extends downwardly from a first end of the horizontal land toward the first edge so that the first bottom surface forms an angle with the horizontal land. A second bottom surface extends downwardly from a second end of the horizontal land projecting toward the second edge so that the second bottom surface forms an angle with the horizontal land. Optionally, the receptacle includes a wall at the second edge and the second bottom surface intersects the wall to form a pocket, such as a v-shaped pocket. Optionally, the first bottom surface forms a ramp guiding documents to a bin or other container for receiving documents. 
     While the methods and apparatus are described herein by way of example for several embodiments and illustrative drawings, those skilled in the art will recognize that the inventive methods and apparatus for sorting items using a dynamically reconfigurable sorting array are not limited to the embodiments or drawings described. It should be understood, that the drawings and detailed description thereto are not intended to limit embodiments to the particular form disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the methods and apparatus for sorting items using one or more dynamically reconfigurable sorting array defined by the appended claims. Any headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims. As used herein, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include”, “including”, and “includes” mean including, but not limited to. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The foregoing summary and the following detailed description of the preferred embodiments of the present invention will be best understood when read in conjunction with the appended drawings, in which: 
         FIG. 1  is a perspective view of a system for processing documents; 
         FIG. 2  is a plan view of the system illustrated in  FIG. 1 ; 
         FIG. 3  is a side elevational view of the system illustrated in  FIG. 1 ; 
         FIG. 4  is an enlarged fragmentary plan view of a sorter of the system illustrated in  FIG. 1 ; 
         FIG. 5  is a fragmentary plan view of the system illustrated in  FIG. 1 ; 
         FIG. 6A  is an enlarged fragmentary plan view of a portion of the sorter illustrated in  FIG. 4 ; 
         FIG. 6B  is an enlarged fragmentary side elevational view of the portion of the sorter illustrated in  FIG. 6A ; 
         FIG. 6C  is a fragmentary perspective view of the portion of the sorter illustrated in  FIG. 6A ; 
         FIG. 6D  is an exploded fragmentary perspective view of the portion of the sorter illustrated in  FIG. 6C . 
         FIG. 7  is an enlarged side elevational view of a printing assembly of the system illustrated in  FIG. 1 ; 
         FIG. 8  is a perspective view of the printing assembly illustrated in  FIG. 7 ; 
         FIG. 9A  is an enlarged fragmentary perspective view of sorting station of the sorter illustrated in  FIG. 4 , illustrating cross belt assemblies in a de-activated position; 
         FIG. 9B  is a perspective view of the sorting station illustrated in  FIG. 9A , illustrating the cross-belt assemblies in a partially activated position; 
         FIG. 9C  is a perspective view of the sorting station illustrated in  FIG. 9A , illustrating the cross-belt assemblies in an activated position; 
         FIG. 10  is a fragmentary end view of a portion of one of the cross-belt assemblies illustrated in  FIGS. 9A-C ; 
         FIG. 11A  is a fragmentary end view of a portion of one of the cross-belt assemblies illustrated in  FIGS. 9A-C , showing the cross-belt assembly in the de-activated position; 
         FIG. 11B  is fragmentary end view of the cross-belt assembly illustrated in  FIG. 11A , showing the cross-belt assembly in the partially activated position; 
         FIG. 11C  is a fragmentary end view of the cross-belt assembly illustrated in  FIG. 11A , showing the cross-belt assembly in the activated position; 
         FIG. 12  is a perspective view of the cross-belt assembly illustrated in  FIGS. 11A-C ; 
         FIG. 13  is an enlarged perspective view of sort locations of the sorter illustrated in  FIG. 4 ; 
         FIG. 14  is an enlarged plan view of one of the sort locations illustrated in  FIG. 13 ; 
         FIG. 15  is across-sectional view of the sort location illustrated in  FIG. 14  taken along line  15 - 15 ; 
         FIG. 16A  is a perspective view of an end of the sorting station illustrated in  FIG. 4 , with a sort tray illustrated in a lower position. 
         FIG. 16B  is a perspective view of the sorting station illustrated in  FIG. 17A , with the sort tray illustrated in an upper position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Some portions of the detailed description which follow are presented in terms of operations on binary digital signals stored within a memory of a specific apparatus or special purpose computing device or platform. In the context of this particular specification, the term specific apparatus or the like includes a general-purpose computer once it is programmed to perform particular functions pursuant to instructions from program software. In this context, operations or processing involve physical manipulation of physical quantities. Typically, although not necessarily, such quantities may take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared or otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to such signals as bits, data, values, elements, symbols, characters, terms, numbers, numerals or the like. It should be understood, however, that all of these or similar terms are to be associated with appropriate physical quantities and are merely convenient labels. Unless specifically stated otherwise, as apparent from the following discussion, it is appreciated that throughout this specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining” or the like refer to actions or processes of a specific apparatus, such as a special purpose computer or a similar special purpose electronic computing device. In the context of this specification, therefore, a special purpose computer or a similar special purpose electronic computing device is capable of manipulating or transforming signals, typically represented as physical electronic or magnetic quantities within memories, registers, or other information storage devices, transmission devices, or display devices of the special purpose computer or similar special purpose electronic computing device. 
     Referring now to the figures in general and to  FIGS. 1 and 2  in particular, a system is illustrated, which includes a document scanning workstation  10  and sorting station  110 . The system is configured to process a variety of documents, including mail. In particular, the system has the capability of processing a variety of different sized documents. The system may selectively scan and sort the documents depending on a variety of criteria. Additionally, the system may include elements for facilitating the processing of mail, such as by opening envelopes and facilitating the extraction of documents from with the envelopes. In particular, the system may be configured in a variety of configurations that may or may not include elements designed to facilitate extraction of documents from envelopes. 
     Referring to a first embodiment illustrated in  FIG. 1 , the workstation  10  is configured to facilitate the processing of documents in the form of envelopes containing items. The system is also able to process documents that have been extracted from envelopes or any other type of document. Accordingly, in the following discussion, when used throughout the description and the claims, unless otherwise noted, the term document may refer to any type of written or printed matter and may include envelopes and other mail pieces. 
     The workstation  10  includes a scanner  60  for scanning the documents to obtain image data for the documents. Additionally, the workstation may include any of a variety of feed mechanisms for feeding documents to the scanner. In the exemplary embodiment illustrated in  FIGS. 1-3 , the system may include a horizontal drop conveyor  40  configured to receive documents in a substantially flat or horizontal orientation. The drop conveyor  40  conveys the documents to a feeder  50 . The feeder is configured to serially feed the documents to the scanner  60 . The feeder  50  is preferably configured to accommodate a packet of documents so that the feeder can receive the packet from the drop conveyor  40  and then singulate the packet of documents so that the documents are serially fed to the scanner  60 . 
     As shown in  FIGS. 1 and 3 , the workstation  10  includes a plurality of support legs  20  that elevate the work surface, including the drop conveyor  40  and the scanner  60 . In the present instance, the support legs  20  are extendable legs so that the height of the workstation can be raised or lowered within a range depending on the height desired by the operator. Any of a variety of adjustment mechanisms can be utilized to raise or lower the support legs. Preferably the adjustment of the two legs is controlled so that both legs  20  raise and lower together. For instance, the adjustment mechanism may be interconnected with both legs so that both legs raise or lower together. In the present instance, the support legs  20  are telescoping legs and each leg includes a drive mechanism for raising and lowering each leg. The drive mechanism for the two legs  20  are synchronized so that the legs raise and lower together. The drive mechanism can be any of a variety of mechanisms, including, but not limited to hydraulic mechanisms and spindle drive mechanisms. Additionally, the drive mechanisms can comprise an electric pump, motor or manual drive element, such as a hand crank. If the drive mechanisms are automated, operation of the drive mechanisms may be controlled by an electronic controller, including a manually actuable switch. Alternatively, the controller may be interconnected with the central processor  90  of the workstation and actuation of the drive mechanisms may be controlled through an input mechanism such as the touch screen  80 , a mouse, a button or other input element. In response to the input signal received from the operator, the central controller  90  may control operation of the drive mechanisms to raise or lower the legs  20 . 
     At the scanner  60 , each document is scanned to obtain optical image data for each document. After being scanned, the documents are then sorted to one of a plurality of output bins  70 . Alternatively, after being scanned the documents are discharged to a bypass or through path  75 . From the through path, the documents may be further processed as discussed further below. 
     The operation of the different stations is controlled by a central controller, such as a microprocessor  90 . The central controller may also function as an image processor. Specifically, the microprocessor may be configured to process the image data obtained by the scanner. For instance, the image processor  90  may process the image data to attempt to identify and read text. Similarly, the image processor may attempt to identify and read a marking, such as a bar code. Additionally, the system may include an input/output device that provides information to the operator and allows the operator to input information regarding the documents being processed. For instance, the operator may input data that controls how a batch of documents are processed. Additionally, the operator may input information that controls how a particular document or packet of documents is processed. As shown in  FIG. 1 , the input/output device may be a touch screen display  80 . Alternatively, the system may include any of a variety of input mechanisms, such as a mouse, touch pad, stylus or keyboard. 
     As described above, the system illustrated in  FIG. 1  may be configured to process documents, such as envelopes containing contents. The details of an exemplary system that describes the details of the input bin  20 , the envelope opening station  25  and the extraction station are described in detail in U.S. Pat. No. 8,919,084. The entire disclosure of U.S. Pat. No. 8,919,084 is hereby incorporated herein by reference. Additionally, the details of an exemplary drop conveyor  40 , feeder  50  and scanner  60  are described in detail in U.S. Pub. Appl. No. 2015/0319330, filed May 15, 2015. The entire disclosure of U.S. Pub. Pat. Appl. No. 2015/0319330 is hereby incorporated herein by reference. 
     According to one aspect, the present system is directed to improving the flow of documents in a document processing system. The system has particular application to workstations directed to processing documents and has particular application to processing packets of documents. In an exemplary embodiment, the workstation is configured as a semi-automated system for processing documents of a variety of types, including documents of varying size as well as folded documents, such as documents extracted from envelopes. As described above, the system may be incorporated into a larger system that includes elements such as a cutting station for cutting open envelopes and an extraction station for opening the envelopes to present the documents to the user for extraction. However, it should be understood that the present system has application to systems that do not incorporate document extraction features but are instead directed to processing documents generally. For instance, features of the present system may be incorporated into a system that does not include extraction features, but includes the horizontal conveyor, scanning station and sorting station. Further still, features of the system may have application generally in a document processing system in which it is desirable to manually feed packets of documents into the system without organizing or otherwise preparing the packets for feeding into the system. 
     Document Scanning 
     With the foregoing in mind, a general overview of the flow of documents through the workstation  10  is as follows. Initially, one or more documents are provided for processing. For instance, a stack of envelopes containing documents, referred to as a job, is provided. To process the documents, the operator unfolds as needed and drops or places the documents onto a drop conveyor  40  that transports the documents toward a scanner or imaging station  60 . An imaging entry feeder  50  receives the documents from the drop conveyor  40  and controls the feeding of the documents into the imaging station  60 . The image entry feeder  50  is configured to receive and feed documents of various sizes and condition. For instance, frequently documents are folded in an envelope. When the documents are extracted and opened, the documents are creased or folded so that they do not lie flat. The feeder  50  is preferably configured to receive such creased or folded documents and serially feed the folded documents into the imaging station  60  with minimal manual preparation by the operator. 
     The imaging station  60  includes an imager that obtains image data for each document as the document is conveyed past the device. For instance, preferably the imager is a scanner that obtains gray scale or color image data representing an image of each document. The scanner scans each document at a plurality of points as the document is conveyed past the scanner. Data acquired by the scanner is then processed by one or more image processors. The image processors may be in the form of microprocessors on a separate imaging computer that is connected with the line scan camera. However, in the present instance, the image processor is an embedded processor in the line scan camera assembly. The image processor is operable to convert the image data to gray scale, such as 8-bit grey scale. Additionally, as discussed further below, the image processor is operable to binarize the gray scale image data to create a black and white representation of the document image. 
     By binarizing the data, the data for each pixel is converted from an eight-bit gray scale representation to a one bit black or white representation, which significantly reduces the processing required to make certain determinations for the document that may be used to control further processing as discussed further below. For instance, binarizing the image data highlights portions of the image that include text or other printed matter. 
     To binarize an image, the gray scale data for each pixel of the image is compared with a threshold. If the gray scale number for a pixel is above the threshold, the gray scale is converted to white. Conversely, if the gray scale number is below the threshold, the gray scale is converted to black. 
     To account for variations among the different documents being processed, an adaptive threshold may be used so that the binarization threshold is variable for each document. An adaptive threshold uses a different threshold for each document based upon a sampling of the image data for the document. 
     In addition to binarizing the image data, the image data may be filtered to reduce noise, which eliminates unnecessary background and stray marks from the document image. The noise filtering can be performed either in series or in parallel with the binarization. 
     The image data may then be stored in a short term or long-term storage device. For instance, the system may be connected with a network so that the document images may be exported and stored on a server  250 , such as a file server. The server may be local, or it may be remote. As discussed above, the system may binarize the image data to create a black and white image. In the present instance, the binarized data is analyzed and used to control the further processing of the document. However, the binarized image data need not be stored on the file server. Instead, the grey-scale image data is stored on the image server. 
     From the imaging device, an imaging transport conveys the documents to a sorting station  70  that sorts the documents into a plurality of output bins. The documents can be sorted in a variety of ways. For instance, the documents can be sorted based on document information obtained from the image data received at the imaging station  60 . Alternatively, the operator may indicate information regarding a document before it is scanned, so that the document is sorted according to the information indicated by the operator. Yet another alternative is that the documents may be stacked into one or more bins simply based on the order in which the documents are processed. 
     A controller  90  controls the processing of the mail in response to signals received from various sensors at various locations of the workstation  10  and in response to parameters set for the job by the operator. 
     Sorting Station 
     As noted above, documents may be processed by the workstation  10  by scanning and sorting the documents to output bins  70 . Alternatively, documents may be scanned and directed to a bypass path  75 . Referring to  FIGS. 1-3 , documents directed to the bypass path  75  are fed to a sorting station  100 . 
     The sorter 100  includes an input conveyor  110  for receiving documents. The input conveyor conveys the documents to a printing station  130  that selectively prints indicia on the documents. From the printing station  130  the documents are conveyed to an output conveyor  150 . A sorting station  160  sorts the documents to a plurality of output locations, such as output bins  220 A-C. A reject bin  225  may also be provided for receiving items from the output conveyor  150 . 
     Referring to  FIGS. 2-4  the details of the sorter  100  will be described in greater detail. The input conveyor  110  is configured to facilitate receiving documents from the bypass path  75 . The input conveyor may comprise any of a number of mechanisms for conveying documents, such as belts or rollers. In the present instance, the input conveyor comprises a generally horizontal surface configured to receive documents in a horizontal orientation (i.e. a face of the document is generally horizontal). Additionally, the conveyor may be configured to convey the documents without positively entraining the documents. For example, the input conveyor may be a generally horizontal conveyor belt so that documents can be conveyed face down or face up on the belt. As illustrated in  FIG. 3 , the input conveyor  110  in the illustrated embodiment may optionally comprise a plurality of elongated rollers  112 . The rollers may be rotatable around generally horizontal axes and may be driven by a drive element, such as one or more belts that rotate the rollers. Documents fed onto the input conveyor  110  may ride on top of the rollers  112 . 
     The sorter  100  and the workstation  10  may be formed as a single rigidly interconnected unit. However, in the present instance, the sorter  100  is functionally interconnected with the workstation  10  while being moveable relative to the workstation. For instance, the system may include an optional bypass insert  120  disposed in the bypass path  75 . The insert  120  provides a stop the impedes relative translation between the sorter and the workstation while allowing relative motion in one or more different directions as discussed below. 
     Referring to  FIGS. 6A-6D , the workstation includes a bypass path  75  that extends away from the scanner  60 . The bypass path  75  allows documents to travel from the scanner  60  directly to the sorter  100 . The end of the bypass path  75  remote from the scanner forms an enlarged opening having a height “h” and a depth “d” as shown in  FIG. 6B . Documents conveyed through the bypass  75  exit through the discharge opening  77  onto the input conveyor  110  of the sorter. 
     The bypass insert  120  nests into the discharge opening  77 . In particular, the bypass insert is a generally U-shaped channel having an upper leg  121  and a lower leg  122  connected by a central web  123 . The upper leg  121  may be a generally horizontal planar surface extending transverse and intersecting with an upper edge of the web  123 . Similarly, the lower leg  122  may be a generally horizontal planar surface extending generally parallel to the upper leg and extending transverse to and intersecting with the web  123 . The insert  120  nests within the discharge opening  77  of the bypass path so that one or both of the upper and lower legs  122  abut a surface of the bypass path. With the insert  120  abutting a surface of the discharge opening  77  the surface of the discharge opening impedes further displacement of the insert toward the bypass path  75  and scanner  60 . In this way, the vertical wall of the web  123  of the insert forms a longitudinal stop impeding relative movement of the sorter  100  in the direction of the document path toward the scanner. Specifically, from the perspective of  FIG. 6B , the rightmost edge of the sorter forms a wall or edge that butts up against the web  123  of the insert. In this way, the sorter is not rigidly connected with the workstation so that the sorter can be displaced longitudinally away from the workstation along the direction of the document path, however, the insert operates as a stop impeding the sorter from being displaced longitudinally toward the workstation along the direction of the document path. Further still, the insert operates as a depth stop so that when the sorter abuts the insert, the distance from the scanner to the print station  130  is known. 
     Referring to  FIG. 6A and 6D , the insert may include a lateral stop block  124  for impeding relative displacement between the sorter  100  and the workstation in a lateral direction that is transverse the document path. For instance, the lateral stop  124  may be a block rigidly connected with the web  123 . The sorter  100  may have a rigid side wall  115  forming a back wall of the input conveyor  110 . As shown in  FIG. 6A , the stop block  124  abuts the side wall  115  when the end wall of the input conveyor  110  abuts the web  123  of the insert. Accordingly, the stop  124  impedes lateral displacement of the sorter relative to the workstation in a direction toward the back of the sorter (i.e. from left to right from the perspective of  FIG. 6A ), while still allowing the sorter to be displaced laterally in a direction toward the front of the sorter (i.e. from right to left from the perspective of  FIG. 6A ). 
       FIGS. 6A-6D  also illustrate a non-rigid interconnection between a guide  125  rigidly connected with the workstation  10  and a sensor  128  rigidly connected with the sorter  100 . The sensor  128  provides signals to a controller to control the height of the sorter  100  in response to the height of the workstation. 
     If the height of the input conveyor  110  is higher than the discharge path  75  the documents exiting through the discharge opening  77  will tend to butt up against the end of the sorter, thereby causing a jam. Similarly, if the height of the discharge opening  77  is significantly higher than the input conveyor  110  then the leading edge of documents may tend to fall into the gaps between the rollers  112  of the input conveyor. Accordingly, it is desirable to maintain the height of the input conveyor within a range relative to the height of the workstation. 
     Referring to  FIG. 3 , the sorter includes a plurality of legs  105  that support the sorter. Similar to the legs  20  of the workstation, the legs  105  are adjustable to raise or lower the height of the sorter. Like the legs of the workstation, the legs of the sorter may be any of a variety of adjustable legs, including but not limited to hydraulic legs and spindle drive legs. If the legs are functionally interconnected with workstation, then the sorter includes an electronically controllable drive mechanism  107  for automatically driving the legs  105  and a controller  109  for controlling the operation of the drive mechanism or drive mechanisms. For example, the sensor  128  may provide signals to the controller  109  and the controller may control the drive mechanism(s)  107  to raise and lower the height of the legs  105  in response to the signals received by the sensor  128 . 
     Referring again to  FIGS. 6A-6D , the sensor  128  is a switch having an actuator  129 . A bracket connected to the input conveyor and the sensor  128  rigidly connects the sensor to the sorter  100 . Additionally, a connecting bracket  125  is rigidly connected with the workstation  110 . The connecting bracket  125  includes a notch  126  configured to receive the actuator  129  of the sensor. In this way, the actuator extends into engagement with the notch  126  in bracket  125 . Therefore, when the legs of the workstation  10  are raised the bracket  125  is also raised. When the bracket  125  is displaced upwardly the movement displaces the sensor actuator  129  upwardly. In response to the actuation of the actuator upwardly the sensor  128  provides a first signal to the controller  109 . In response to the first signal the controller controls the drive mechanism to raise the legs  105 . As long as the workstation is being raised relative to the sorter, the connecting bracket  125  will actuate the actuator upwardly and the sensor will continue to send the first signal to the controller. Similarly, when the legs of the workstation  20  are lowered the connecting bracket will displace the actuator  129  downwardly. In response to the downward actuation of the actuator  129 , the sensor will provide a second signal to the controller  109 . In response to the second signal the controller controls the drive mechanism  107  to lower the legs. Again, the downward actuation of the actuator  129  will continue as long as the workstation is lower relative to the sorter. 
     In this way, as described above the sorter is functionally linked with the workstation without being fixedly linked with the workstation. Additionally, the functional link allows the sorter to automatically follow the height of the workstation when the workstation is adjusted so that the height of the sorter relative to the workstation is maintained within a predetermined range. Additionally, the functional link allows the sorter to follow the workstation without the need of an electronic connection between the controller controlling the height of the sorter legs  105  and the controller controlling the height of the workstation legs  20 . 
     The input conveyor  110  conveys documents from the scanner  60  to the printer station  130 . At the printer station  130  an identifying mark may be selectively applied to the document. For instance, the printer station  130  may apply a bar code or other identification mark on a document. The printer station  130  may also print human readable markings, such as text or graphics. 
     Print Station 
     The print station  130  includes one or more print heads  148 . The printer may be any of a variety of print heads and in the present instance, the print head is a fixed print head  148 . The system may control the actuation of the print head  148  to control the area on the document on which the print head prints. Specifically, the system may be configured so that the printer prints in a consistent location on each document. The controller that controls the print station can control the actuation of the print head to control the location where the printer prints along the length of the document. Specifically, a sensor may be positioned adjacent the print station to detect the leading edge of the document as the document enters the print station. Alternatively, the system tracks the document as it passes through the scanner  60 . Based on the known distance from the scanner to the print head and the known speed of the document as it is conveyed to the print head from the scanner, the controller controls when the print head is actuated while the document passes under the print head. A shorter delay from when the lead edge of the document is detected will cause the printer to print closer to the leading edge of the document. A longer delay will cause the printer to print closer to the trailing edge. 
     Although the system may be configured to print in a consistent location, it may be desirable to selectively vary the location where the printer prints on the documents. For instance, as discussed below, the system may scan the document to identify an area free from text or graphics. The system may then control the print station to print the indicia in the desired location. Specifically, to control the area of printing the system may vary the timing of actuating the print head to control the area along the length of the document where the print head prints. In this way, the selective actuation of the print head may be based on identification of the desired print location for the document, detection of the leading edge of the document and the document speed as the document is conveyed past the print head. 
     The print station may also include elements for controlling the position of the print heads. Specifically, the print head  148  may be mounted on a carriage  132  that is moveable across the width of the document. Referring to  FIGS. 7-8 , the print station  130  may include a horizontal rail  131  that extends across the width of the conveyor  110 . The rail  131  supports the carriage  132 . In particular, the carriage slidably engages the rail so that the carriage is displaceable across the width of the conveyor. 
     In addition to moving the print head  148  in a horizontal direction, the print station  130  may be configured so that the print heads can be displaced in a vertical direction. For instance, a job may include the processing of courier packs, such as Federal Express mailers. Such documents are significantly thicker than documents such as normal piece of mail, such as a typical #10 envelope. Accordingly, print head  132  may move so that the distance between the document and the print head is consistent regardless of the document thickness. 
       FIGS. 7-8  illustrate an embodiment with an optional print station  130  that incorporates a carriage that includes a mechanism for varying the height of each document as the document is processed to promote a uniform distance between the face of each document and the print head  148 . The print station optionally includes a print head  148  connected with the carriage by a four-bar linkage. The four-bar linkage is connected with a follower that engages each document as it is conveyed under the print head. The linkage includes a first generally vertical bar  134  that is substantially fixed during operation. The linkage includes a second generally vertical bar  135  connected with the print head  148  so that the second bar is constrained against movement relative to the print head. A pair of coupler links  136  interconnect the first and second bars. Since the coupler links  136  are pivotable connected with the first and second link, the second link  135  is vertically displaceable relative to the first link  134  during use. 
     The printer station  130  also includes one or more follower elements configured to engage the documents as the documents enter the print station. For instance, as shown in  FIG. 8  a sled  139  may be connected to the bottom of the print head. The sled  139  is a generally horizontal plate or platen configured to ride on the top surface of a document as the document passes under the print head. Additionally, the print assembly may include one or more following elements upstream from the print head  148 . For example, the second link  135  may be a generally L-shaped link having a generally horizontal leg. A pair of entry roller  138 A, B may be rotatably connected with the second bar  135 . The horizontal leg of bar  135  may be angled so that the first entry roller  135 A is positioned vertically higher than the second entry roller. In this way, the gap between the circumferential surface and the top surface of the input conveyor  110  is greater than the distance between the circumferential surface of the second entry roller  138 B and the top surface of the input conveyor as shown in  FIG. 7 . 
     Configured in this way, as the conveyor  110  conveys a document to the print station  130 , if the document is thicker than the distance between the entry roller  138 A and the conveyor, the entry roller  138 A will engage the top face or surface of the document and the document will push upwardly on the entry roller  138 A. In response to the upward push by the document, link  135  will pivot upwardly relative to fixed link  134  that is fixed vertically relative to the overhead rail  131 . As the document progresses the document will engage the second entry roller  138 B. Since the gap between entry roller  138 B and the conveyor  110  is less than the gap between the first entry roller  138 A and the conveyor, the document will engage the second entry roller. As the document engages the second entry roller  138 B the document will push upwardly on the entry roller. In response to the upward push, the second link  135  will be displaced upwardly further upwardly to allow the document to pass under the second entry roller  135 B. As the document is conveyed under the second entry roller, the document passes between the sled  139  and the conveyor  110 . Since the sled is rigidly connected with the second link  135 , when the document passes under the sled the document will tend to push upwardly on the sled, which in turn drives the second link upwardly along with the print head  148 . In this way, the sled  139  rides on the top surface of the document. Since the print head  148  is fixed relative to the sled, the distance from the print head to the surface of the sled in a known and fixed distance. Therefore, as the documents pass under the print head, the linkage of the print station allows the print head to be displaced vertically to position the print head at a uniform and consistent distance relative to the upper surface of the document. 
     The weight of the linkage and the sled pushing down on the document as the document passes under the print head  148  may create undue friction that could lead to the document buckling or crumpling. Accordingly, the print station  130  may include an element to reduce the force pushing the sled  139  downward during use. For instance, as shown in  FIG. 7 , a biasing element may be connected with one of the coupler links  136  or with the second link. The biasing element may be a spring or other element that pulls upwardly to reduce the downward force exerted on the sled by the weight of the linkage and the print head. 
     The carriage  132  may include a height adjustment assembly  140  for adjusting the gap between the sled  139  and the surface of the conveyor  110 . The height adjustment assembly  140  includes an adjustment knob  142  connected with a threaded post  144  that engages a threaded insert  146 . The threaded insert  146  is connected with the second link  135 . In this way, rotating the knob  142  in a first direction operates to raise the second link  135 , which in turn raises the sled  139  attached to the second link. Conversely, rotating the knob  142  in a second direction operates to lower the second link  135  which in turn lowers the sled  139 . 
     Optionally, the print station can be configured so that the sled  139  and/or the second entry roller  138 B cooperate with the top surface of the conveyor  110  to form a nip with the conveyor as shown in  FIG. 7 . In particular, the sled  139  in  FIG. 7  is illustrated as resting on the rollers  112  of the conveyor  110 . However, if the sled rests on the rollers then the sled is going to be vertically displaced every time a document passes under the print head  148 . Accordingly, to minimize the vertical travel of the print head during use, the height of the sled may be adjusted for each batch of documents. For instance, a document from the batch, such as the thinnest document in the batch, can be selected to provide the height adjustment. The selected document is inserted between the sled and the conveyor. The height adjustment assembly  140  is then operated to lift the sled so that the sled is touching the document but placing minimal weight on the document. In this way, when documents that are as thick as the selected document pass through the printer station  130  the print head will be properly positioned vertically so that the print head will not need to be displaced vertically. When any document thicker than the select document passes through the print station  130  the document only displaces the print head by the difference between the select document and the document being processed. In this way, setting the gap between the conveyor and the print head is operable to reduce the extent of vertical movement of the print head. 
     Sorting Station 
     From the print station  130  the documents are conveyed along an output conveyor  150  to a sorter  160  that selectively sorts the documents to a plurality of output locations, such as receptacles  220 A-C. Referring to  FIGS. 4 and 9A-12  the details of the output conveyor  150  and sorter  160  are described in greater detail below. 
     The output conveyor  150  may comprise any of a number of conveyors, such as one or more conveyor belts, rollers or other elements. Optionally, as shown in  FIGS. 9A-12 , the output conveyor may comprise a plurality of horizontal rollers  152  similar to the rollers  112  described above in connection with the input conveyor  110 . The rollers  152  are driven rollers so that the rollers convey the documents forwardly along the output conveyor. As with the input conveyor  110 , the output conveyor  150  may be configured to convey the documents with the documents riding on top of the roller to that the documents are not positively gripped or entrained by the conveyor. 
     The output conveyor  150  includes a side wall  154  that extends along substantially the entire length of the output conveyor 150 /sorter  160 . The side wall  154  extends upwardly forming a stop preventing documents from falling off the side of the output conveyor  150 /sorter  160 . The rollers  152  may be skewed at an angle relative to the justification rail so that the rollers tend to drive the documents toward the side wall  154 . 
     The sorter  160  is positioned along the output conveyor and is configured to selectively sort documents to a plurality of sort locations  220  based on any of a variety of criteria. For instance, the criteria may be determined during processing at the scanning station  60  or the sort criteria may be based on criteria such as the detected thickness, detected length or other criteria. 
     The sorter  160  may comprise any of a variety of structures adapted to selectively direct documents from a first path to a second path directed toward an alternate output location. In particular, the output conveyor  150  may convey the documents along a document path indicated as arrow  155  in  FIG. 4 . In the present instance, the sorter  160  optionally includes one or more discharge assemblies  170 ,  200 ,  210  that drive the documents traverse the document path  155  toward one of the output areas  220 A-C (discharge assembly  210  is hidden below mail piece  5  in  FIG. 2 ). 
     The sorter  100  includes a discharge assembly for each sort location  220 . The discharge assembly is configured to selectively drive a document off the output conveyor  150  and into one of the sort locations in response to a control signal. In the present instance, the sorter  160  includes three separate discharge assemblies  170 ,  200 ,  210 . The three separate assemblies are independently actuable and all three are configured substantially similarly. 
     Referring to  FIGS. 4 and 9A-12 , the details of the first discharge assembly  170  will now be described in greater detail. It should be understood that the description of the first discharge assembly applies equally to the second and third discharge assemblies  200 ,  210 . 
     The first discharge assembly  170  is an assembly that is recessed between the rollers  152  in the output conveyor  150 . The discharge assembly  170  has various elements that are actuable between two positions. The first position is a recessed or deactivated position, the second position is a raised or activated position. In the recessed position, documents on the output conveyor pass over the discharge assembly. In the raised position, select elements of the discharge assembly raise up above the top surface of the output conveyor to engage the document and drive the document toward the sort location. 
     The discharge assembly includes two elements: a fence  172  for stopping the forward progress of the document and a plurality of cross belt assemblies  180  for driving the document across the document path  155  to the output or sort area. Additionally, the discharge assembly may include three drive controls: a first drive control for raising the fence  172 , a second drive control for raising the cross-belt assemblies  180  and a third drive control for driving the cross-belt assemblies  180  to convey the document to the discharge area. 
     The fence  172  is configured to engage documents on the output conveyor and impede forward displacement along the document path  155 . The fence may be configured in any of a variety of forms to stop documents. In the present instance, the fence  172  is a substantially planar wall having a width that extends across the width of the output conveyor and a height that extends upwardly from the surface of the output conveyor. In the present instance, the fence has a width that is substantially greater than its height. Additionally, the fence  172  has a width that extends across a substantial portion of the width of the output conveyor to ensure that the documents engage the fence when the fence is raised. The height of the fence may vary depending upon the application. In the present instance, the fence is approximately ½″-3″ high. 
     Referring to  FIG. 10 , the fence  172  is connected with a linkage configured to raise and lower the fence. Any of a variety of mechanism can be utilized to raise and lower the fence. In the present instance, an option in disclosed in which the fence  172  is connected with two pivot arms  174  to form a four-bar linkage and an actuator actuates operation of the four bar link. For example, a rotary cam may be provided to actuate and de-actuate the fence. A follower  177  may be connected to one of the pivot arms  174  of the fence linkage. The follower  177  may be any of a variety of fixed or moveable followers. In the present instance, the follower is a cam follower bearing. The follower  177  cooperates with an eccentric radial cam  175 , such as a wedge cam as shown in  FIG. 10 . The follower  177  engages the peripheral surface of the cam  175  so that when the cam is rotated clockwise (from the perspective of  FIG. 10 ) the cam drives the linkage clockwise thereby raising the fence  172 . Additionally, the linkage is biased toward the deactivated or recessed position. Therefore, when the cam is rotated back into the start position as shown in  FIG. 10 , the pivot arms  174  pivot into the recessed or deactivated position to lower the fence  172 . 
     In the embodiment illustrated in the drawings and described above, each discharge assembly includes four separate cross belt assemblies. However, it should be understood that the discharge assemblies may be configured with fewer cross-belt assemblies or more cross belt assemblies. Since the discharge assembly  170  includes a plurality of cross belt assemblies, when a document is to be discharged by the discharge assembly, all the cross-belt assemblies  180  may be raised and actuated to drive the document across the conveyor and into the sort location  220 . Accordingly, the following description describes the structure of one of the cross-drive assemblies  180 , but it should be understood that all of the cross-drive assemblies are configured the same or essentially the same as the assembly  180  described below. 
     The discharge assembly  170  may utilize a variety of elements to selectively control the raising and lowering of each cross-belt assembly. In the present instance, the cross-belt assemblies  180  each includes a four-bar linkage for controlling the raising and lowering of each belt. The linkage includes a pair of pivot arms  185  that are connected by a coupler link  186 . An idler pulley  183  is rotatably connected to the end of each pivot arm  185  and an endless belt is entrained around the two idler pulleys. The belts  182  also passes around driven pulley  184  as shown in  FIG. 11A . 
     A cam controls the activation of the pivot arms  185 . In the present instance, the cam  188  is an eccentric radial cam. The belt assembly linkage includes a follower that cooperates with the cam  188  to raise and lower the belts. As shown in  FIG. 11A , one of the pivot arms  185 A includes an extension that protrudes from the main body of the pivot arm. A follower  187  is connected to the distal end of the protrusion. The follower may be any of a variety of followers. In the present instance, the follower is a cam follower bearing. The cam  188  is an eccentric radial cam that pivots about an axis. Additionally, the control linkage may include a biasing element for biasing the belt  182  toward the retracted position. For example, as shown in  FIG. 11C , a spring  189  biases the second pivot arm  185 B toward the retracted position. 
     Referring now to  FIG. 12 , a pair of motors control the operation of the cross-drive assembly  180 . The first is a motor  190  for driving the cams  175 ,  188  that control actuation of the fences and the belts. The cam motor  190  drives a cam drive shaft  192 . Each cam  175 ,  188  in a cross-drive assembly  170  is mounted on the cam drive shaft  192 . For example, the cross-drive assembly illustrated in  FIG. 12  includes four belt assemblies  180  and one fence assembly. Therefore, one fence cam  175  and four belt cams  188  are mounted on the cam drive shaft  192 .Additionally, the cams  175 ,  188  are configured and oriented so that rotation of the shaft first actuates the fence  172  and then after a delay, continued rotation of the shaft  192  actuates the belts. Specifically, from the recessed position shown in  FIG. 12 , actuating the cam motor drives the shaft  192  in a first direction. As the shaft rotates in the first direction the cam follower  177  on the fence linkage  174  follows the periphery of the fence cam  175  thereby pivoting the fence toward the raised position. However, as shown in  FIG. 11A  prior to actuation of the cam drive shaft, the follower  187  on the belt linkage  185  is spaced apart from the cam  188 . Therefore, while the first rotation of the shaft  192  drives the fence cam  175  against the follower  177 , the belt cam  188  rotates from being spaced apart from the belt follower  187  to being in engagement with the follower. After the fence is raised, continued rotation of the shaft  192  drives the belt cam  188  against the followers to drive the belt linkage, thereby raising the belt  182 . 
     In other words, referring to  FIG. 11A , the cam drive shaft  192  is in a first position in which the fence  172  and the belts  182  are recessed within the rollers of the conveyor. In this first position, the fence cam  175  engages the cam follower  177 , but the belt cam  188  is spaced apart from the belt follower  187 . Actuating the cam drive motor  190  drives shaft  192  in a first direction by a first angular amount. As the shaft  192  is rotated by the first angular amount, the cam  188  drives follower  187  thereby raising the fence. When the shaft  192  is driven by the first angular amount, the belt cam  188  rotates from a first angular position in which the cam is spaced apart from the follower  187  to a second position in which the cam engages the follower but does not actuate the follower as shown in  FIG. 11B . From the second position, the motor  90  drives the shaft a second angular amount, thereby rotating the fence cam  175  and the belt cam  188  a second angular amount. The fence cam is configured so that continued rotation by the second angular amount does not significantly displace the fence linkage further. However, the continued rotation of the belt cam  188  by the second angular amount actuates the belt linkage driving the belt  182  into the raised position as shown in  FIG. 11C . 
     The belt assembly also includes a drive motor  195  that drives a shaft  197  connected with each driven pulley  184  of each belt assembly  180 . Accordingly, driving motor  195  drives each driven pulley, which in turn drives each belt  182  to drive a document from the output conveyor  150  to one of the sort locations  220 . 
     Sort Receptacles. 
     As discussed above, the sort station  160  selectively directs documents to sort locations  220 . The number and configuration of the sort locations may vary depending on the application. For instance, the sort locations may be bins positioned next to the conveyor  150 . Alternatively, as shown in  FIGS. 13-15  the sort locations may comprise receptacles configured to facilitate self-clearing so that the documents do not build up and create a jam. In an exemplary embodiment, the system includes three receptacles  220 A-C configured to direct documents to sort bins  245  below the conveyor  150 . 
     Since the system processes mixed batches of documents of varying shapes and sizes it is possible for the intermixed documents to get caught up or jammed between the conveyor  150  and the bottom of the receptacle  220 . For instance, long mail pieces (e.g. pieces that are nearly as long as the width of the conveyor belt) may be discharged in a manner that the leading edge of the document butts against a bottom surface of the receptacle while the trailing edge of the document remains on the edge of the conveyor  150  or leans against the edge  115  of the sorter. In such a situation, the document can create a bridge extending between the receptacle  220  and the conveyor  150  which create a backup or jam for subsequent documents. Further still, the conveyor  150  and the cross-belt assemblies  180  do not positively entrain the documents. Instead, the documents ride on top of the conveyor  150  and cross belt assemblies. Therefore, potential slippage between the conveyor  150  or the cross-belt assemblies limits the force that can reasonably be applied to the documents to discharge the documents into the receptacles. Accordingly, in some applications it may be desirable to provide a receptacle  220  that is configured to promote the flow of documents into the bottom of the receptacle. 
     Referring to  FIGS. 13-15  an optional self-clearing receptacle  220  is illustrated. The receptacle is configured to clear documents sorted into the receptacle without need for operator intervention. The illustrated embodiment includes three receptacles  220 A-C, but it should be understood that each receptacle is substantially similar. Therefore, the following discussion applies equally to each of the receptacles. 
     Each receptacle  220  includes a front edge  222  at the edge of the conveyor and a back wall  224  opposing the front edge. The back wall may be substantially parallel with the font edge  222 .a pair of spaced apart sidewalls  225  extend between the front edge  22  and the back wall  224 . The side walls  225  may be substantially parallel to form a generally rectilinearly shaped receptacle. The receptacle may be configured to operate as a bin, however, in the present instance the receptacle  220  is configured to direct documents through an opening  240  in the bottom of the receptacle. Documents pass through the opening  240  and into a storage container, such as a bin  245 . In this way, the receptacle may operate as a chute or guide for guiding/directing documents from the conveyor to the appropriate bin  245 . 
     The interior surfaces of the receptacle  220  are configured to facilitate the passage of a variety of document configurations through the receptacle and into the bin  245 . Specifically, the interior surface of the receptacle is a multi-faceted interior. The bottom of the receptacle  220  is configured to direct documents downwardly toward the discharge opening  240  and into the bin  245 . The bottom includes a plurality of sections. A first facet  230  comprises a generally planar wall intersecting a lower edge of the back wall. The first facet angles upwardly forming an acute angle with the lower edge of the back wall. In this way, the first facet  230  has a first edge that intersects the back wall and a second edge that is elevated above the first edge thereby forming a V-shaped pocket. 
     A second facet  232  of the bottom of the receptacle is a generally or substantially horizontal ledge or shelf. The ledge  232  has a first edge that intersects the second edge of the first facet  230 . The ledge  232  also has a second edge that may be substantially parallel to the first edge to form a horizontal shelf. 
     A third facet  234  of the interior has a first edge that intersects the second edge of the ledge  232 . From the intersection with the ledge, the third facet slopes downwardly at an acute angle relative to the horizon so that the second edge of the third facet is vertically below the first edge that intersects the ledge. A fourth facet  236  has a first edge that intersects the second edge of the third facet. From the intersection with the third facet, the fourth facet slopes downwardly away from the third facet at an acute angle relative to the horizon. The angle that the fourth facet forms with the horizon is greater than the angle that the third facet forms with the horizon so that the fourth facet slopes at a steeper rate. The fourth facet  236  is substantially deeper than the first three facets. Additionally, the fourth facet provides a ramp to direct documents toward the bin  245  below the receptacle  220 . 
     As shown in  FIG. 14 , each of the facets extends substantially the entire length of the receptacle, wherein the length is the dimension extending from the right-side wall  225  to the left side wall  225 . Further, the width of each facet may be different. For instance, as shown in  FIG. 14 , the width of the receptacle extends from the edge  115  of the conveyor  150  to the back wall  224 . The width of the receptacle is preferably similar to the width of the conveyor  150 . For instance, the width of the conveyor  150  (i.e. as measured along the axis of rotation of the rollers  152 ) is approximately 12 inches. The width of the receptacle  220  is greater than 10 inches and may be less than 15 inches. In the embodiment illustrated in  FIGS. 13-15  the width of the receptacle is approximately 12.5 inches. The fourth facet has a width that is significantly larger than any of the first three facets. For instance, the width of the fourth facet  236  may be approximately half the width of the conveyor. Additionally, the first facet is narrower than the second facet and the third facet is narrower than both the first and second facets. 
     Configured as described above, the receptacle has a multi-faceted interior that progressively angles away from the conveyor. In other words, in the direction of travel of the documents that are ejected from the conveyor  150  to the receptacle  220 , the first facet along the direction of travel is the fourth facet  236 , which faces toward the direction of travel at the most acute angle. The next facet along the direction of travel is the third facet  234 , which faces toward the direction of travel at a shallower angle that the fourth facet. The next facet along the direction of travel is the second facet  232 , which is general horizontal so that it is generally parallel to the direction of travel. Finally, the final facet is the first facet  230 , which faces away from the direction of travel. 
     The length of each facet is selected to improve the likelihood that a document will move down the receptacle toward the bin  245  under the influence of gravity without getting caught on the surface of the conveyor  150  or the side  115  of the conveyor. For instance, long documents will tend to pass over the ledge  232  so that the leading edge of the document either impacts the back wall  244  or drops into the pocket formed between the back wall  224  and the first facet  230 . Such a long document will be long enough that the center of gravity of the document is positioned over the third facet  234  so that the document will tend to slide down the fourth facet  236  into the bin  245 . Conversely, if the document is relatively short the leading edge may tend to strike the third facet  234 . Due to the shallow angle that the third facet forms with the horizon, the document will resist forming a bridge between conveyor and the third facet. Instead the document will tend to pass over the third facet and then slide down the fourth facet toward the bin  245 . In yet another example, if a long document slips on the belt assembly so that the belt does not provide much force driving the document into the receptacle  220 , the leading edge of the document may fall down and impact the angled fourth facet  236 . In such a scenario, the trailing edge of the document may extend upwardly and form a bridge with the edge  222  or  115 . However, the trailing edge is also likely to extend above the height of the conveyor surface. Therefore, a subsequent document conveyed to the receptacle is likely to drive the trailing edge of the document over, flipping the document in the receptacle so that it slides down the bottom into the bin  245 . From these examples, it can be seen that the configuration of the interior of the receptacle tends to promote sorting of the documents to the bins  245  without causing jams or backups. 
     Reject Bin 
     As shown in  FIGS. 2,4 and 5 , a reject bin may be positioned at the end of the horizontal ledge  232  of the output conveyor  150 . Documents that are not sorted by the sorter  160  to one of the receptacles  220 A-C are discharge to the reject bin. In this way, the reject bin  225  operates as a separate sort location. Accordingly, the reject bin may be utilized as a fourth sort location so that the documents may be sorted to one of the four sort locations based on criteria detected during processing of the documents. 
     In the previous discussion, the bin at the end of the conveyor is described as a bin  225  that either receives rejected pieces or operates as a fourth sort location. Alternatively, the end of the output conveyor  150  may be configured to include a low volume tray  230  and a high-volume sort bin that is similar to sort bins  220 A-C. Specifically, referring to  FIGS. 16A, 16B , the low volume sort tray  230  overlies the bin  225 . The tray is a shallow tray that is pivotable between an upper position and a lower position. Referring to  FIG. 16A , the forward end of the tray  230  is open so that when the tray is pivoted into a downward position the forward edge of the tray is below the upper surface of the output conveyor  160  so that document discharging off the end of the output conveyor fall into the tray. However, as shown in  FIG. 16B , when the tray  230  is pivoted into an upper position the forward edge of the tray is spaced above the upper surface of the output conveyor  160 . In this way, when the tray  230  is in the upper position a gap is formed between the tray  230  and the output conveyor. Documents being discharged from the end of the conveyor fall through the gap and into the large bin  225 . The controller controls the operation of the tray to pivot the tray between the upper and lower positions to selectively direct document to either the bin  225  or the tray  230 . 
     Method of Use 
     The workstation  10  and sorting station  100  may be utilized to process a variety of documents using a variety of document workflows. The workstation  10  and the sorting station combine to provide alternate workflows that can be utilized for different batches of documents. For instance, a first batch of documents may be a stack of documents in the form of contents that have been extracted from envelopes. For such a job, the operator may input information to the system indicating that the documents for that job are to be scanned by the scanner  60  and sorted to the output bins  70 . Alternatively, the operator may input information indicating that the documents in a job are to be processed by the sorting station  100 . For such a job, the operator drops each document onto the drop conveyor  40  and the system then conveys each piece to the feeder  50 , which feeds the piece to the scanner  60  and discharges the piece through the bypass path  75  to the input conveyor  110  of the sorting station  100 . 
     One method of use sorts the documents based on instructions received on a piece by piece determination. However, the instructions are not provided in real time. Instead, each piece is scanned and the image for the piece is exported to a file server so that the images for the piece can be accessed by a remote user. The user examines the images and provides processing instructions for the different pieces. The pieces are processed during a second pass and each piece is sorted in response to the instructions received for the piece. 
     For example, a job may include numerous documents in the form of mail pieces, such as envelopes containing contents. The recipient of the mail pieces may desire different mail pieces to be processed differently depending on different criteria. For instance, the recipient may want certain pieces to be discarded, such as junk mail. The recipient may desire a second type of mail piece to be extracted and scanned to obtain image data for the enclosed documents. The original documents can then be discarded without being delivered to the recipient. The recipient may desire a third type of mail to extracted scanned to obtain image data for the enclosed document. For this third type of mail, the recipient desires to also receive the original documents. For a fourth type of mail, the recipient may desire the mail to be delivered without being opened. As can be seen from the foregoing, by identifying how the mail is to be processed, a significant portion of the mail may be able to be processed without the need to be physically delivered to the recipient. Although this can significantly reduce the amount of mail to be delivered, it may require the recipient to identify how each piece of mail is to be processed. To do so, the system may scan each piece during a first pass to obtain image data for each mail piece. The image data for each mail piece is exported to a remote server to await instructions from the recipient. For instance, the system may be configured so that when the recipient views the image for a piece of mail the system prompts the recipient to identify how the mail piece is to be processed (e.g. which of the four mail types is the piece). During a subsequent pass through the sorter, the pieces are sorted according to the instructions received for each piece. 
     In order to correlate the document images with the actual mail piece it is desirable to identify each mail piece with a unique identification element, such as a number bar code or other marking. When the recipient views the images for a piece, the instructions received for the piece will be correlated with the unique identifier for the piece. In this way, during a subsequent pass the unique identification element can be scanned and then processed in accordance with the instructions received for that identification number. 
     In view of the foregoing, a method of using the system to process mail may operate as follows. The operator inputs information into the system using the control panel  80  to indicate that the job includes a number of documents to be processed by the sorting station  100 . The operator then drops each piece onto the drop conveyor  40 . The pieces are conveyed to the feeder  50  which feeds the pieces to the scanner  60  which scans the documents to obtain high resolution image data for each document. The image data is exported to a file server or other remote storage to allow the recipient remote access to the stored image data. 
     It should be understood that the image processor  90  for the system is operable to process the image data acquired for a document by the scanner  60 . In particular, the image processor is operable to process the data to identify and read markings on the document. For instance, the image processor  90  may utilize OCR to identify text, such as the recipients address printed on the document. Similarly, the image processor may identify and read markings such as a bar code. For instance, during a second pass the image processor  90  may scan the image data for a document to identify the identification marking printed on the document by the printing station  130  during the first pass. The identification marking can then be used to control the processing of the document in the sorting station  100  as discussed further below. 
     From the scanner  60  the piece pieces are conveyed through the bypass path to the input conveyor  110  of the sorting station. The image data obtained by the scanner  60  may be processed to identify a clear area on the piece where an identification marking can be printed. The image processor may be configured to analyze the image data to identify an area sufficiently clear of marking or printing so that a unique identification marking can be applied to the piece. Although a separate imaging station may be provided, it should be understood that the system may operate without a separate imaging station. Instead, as noted above, the image data for a document may be obtained by the scanner  60  and the image processor  90  may process the image data during the first pass and during subsequent passes as well. Accordingly, it should be understood that any section of this description that details the processing of the image data may be performed by the image processor  90  associated with scanner  60 . 
     From the scanner  60 , the conveyor  110  conveys the piece to the printing station  130 . The imaging station then prints the unique identification marking on the piece in the location where the imaging processor detected a clear zone. Specifically, as described previously, the printing station can control the area on which the marking is printed by controlling the timing of the printing as the document is conveyed past the print head. Additionally, the print head may be moved across the width of the document in response to the identification of the area where the marking is to be printed. 
     After the identification mark is printed on the piece, the piece exits the printing station and is conveyed to one of the discharge areas. During this first pass all the pieces can be sorted to a single output area. After the recipient views the images for the scanned pieces and provides instructions, the pieces are processed during a second pass. Specifically, the operator inputs information into the system via the control panel indicating that the job includes a number of pieces to be processed during a second pass. The pieces are dropped on the drop conveyor  40  and conveyed through scanner  60  where the scanner obtain image data for each document and then discharges the documents through the bypass path  75  to the sorting station  100 . The system then analyzes the image data for a document to search for and read the identification marking. In the present instance, the system imaging processor  90  may process the image data obtained by the scanner  60  during the second pass to attempt to locate and read the identification mark printed on the document by the printing station during the first pass. When the identification number is determined, the instructions received for the piece are retrieved. The sorter then sorts the piece to one of the sort locations  220 A-C based on the instructions received for the piece. However, some of the pieces may not have been viewed by the recipient so the recipient may not have provided instructions for some pieces. Accordingly, pieces for which instructions have not yet been provided are sorted together in one of the sort locations. Alternatively, such pieces may all be discharged to the reject bin  225 . The pieces for which instructions had not been received may be processed again at a later time according to a subsequent processing pass that is similar to the second pass described above. This process is repeated until all the pieces in the job are sorted according to the recipient&#39;s instructions. However, it may be desirable to limit the number of times that a piece is processed or the time frame for receiving instructions from the recipient. For instance, after five days, pieces for which instructions have not been received are automatically processed as mail to be delivered to the recipient without being opened. 
     In the foregoing description, the method included the step of analyzing the image data for a piece to identify a clear zone in the form of an area sufficiently free of marking so that an identification marking can be printed on the piece so that the marking can later be scanned. It may be desirable to print the identification in certain areas of the piece. However, it is desirable to identify clear zones if the desired area is not clear. Accordingly, it may be desirable to scan for the clear zone in a manner that prioritizes certain areas of the document. For instance, the system may process the image data to identify blocks of image data that are free from marking. Such blocks may be clear zones. If a clear zone has an area that is larger than the size of the identification marking, then the clear zone may be a candidate zone for printing the identification marking. However, the document may include more than one candidate clear zones so that the system may select from among the candidate zones to determine the print zone as discussed further below. 
     One such method of scanning for clear zone includes the following steps. First, the piece is scanned to obtain optical image data for a document, such as a mail piece. Specifically, the image data includes image data in three color spaces: red, green and blue. Therefore, each pixel has a red value, a green value and a blue value. The image data for a document is converted to 8-bit gray scale so that each pixel represents a light intensity between 0-255. In order to reduce processing requirements, it may be desirable to select one of the color spaces and convert the image to gray scale using just the single-color space. For instance, rather than using all three-color spaces, the green color space may be selected. The light intensity of each pixel in the green space is converted to a gray scale light intensity. However, in the present instance it may be desirable to separately combine each color space to create the gray scale image. In particular, the image data is processed on a pixel by pixel basis. For each pixel, the corresponding blue value is added to the corresponding red value and the corresponding green value. The combined light intensity for all three-color spaces is then divided by three to provide the corresponding gray scale light intensity from 0-255. The image processor may then process the image data by binarizing the data as described previously above. The image data for the image may then be separated into a plurality of subsets and each subset may be analyzed. For instance, the image data for a piece may be separated into a plurality of separate segments, each represent a portion of the document. By way of example, the document may be divided into a grid or array of blocks. The image data for the document is segmented into a series of data subsets, each corresponding to one of the blocks in the grid. The image processor analyzes the data in each subset to identify the number of black pixels in the subset. If the number of black pixels in below a threshold, the subset or block is identified as a clear zone. The image processor then analyzes the next subset of image data to determine whether the number of black pixels in the subset is below the number of black pixels in the previously processed subset of image data. If the number of black pixels in the subset is lower than the number of black pixels in the previous subset, then the number of black pixels in the current subset becomes the threshold. Each subset is analyzed in this way and compared against the detected black pixel threshold. When a subsequent subset has a black pixel count below the threshold, the subset is determined to be the clear zone. By analyzing the data in stepwise fashion this way, the number of black pixels in the clear zone will continue to reduce until a subset has zero black pixels or until the clearest area is processed. 
     The system may also operate so that a subset is identified as the clear zone (i.e. the area where the identification mark is to be printed) if the subset has a count of black pixels that is within a threshold amount of black pixels of the previously determined clear zone. For instance, if the threshold is 10 and a subsequent subset is determined to have 8 more black pixels than the current threshold value, then the subset being processed is identified as a clear zone and the subsequent subset is compared to the number of black pixels in the clear zone. 
     By way of example, the image data for a piece may be segmented into a series of 54 subsets of data, representing a grid of 6 rows and 9 columns of image data blocks. The clear zone threshold may be initially set at a threshold indicative of the minimum amount a marking that will qualify as a clear zone area. For instance, the clear zone threshold may be initially set at 100. Subset  1  is analyzed, and the number of black pixels is identified. For instance, the number of black pixels may equal 75. Therefore, the clear zone threshold is set at 75. The second subset is examined, and the number of black pixels is 90. The threshold remains set at 75 and the third subset is examined. The third subset is examined, and the number of black pixels is 40. Therefore, the third subset is identified as the clear zone and the threshold is set to 40. The fourth subset is examined, and the number of black pixels is also 40. The threshold remains at 40, but subset four is identified as the clear zone. In this way, the methodology weights or prioritizes blocks or data subsets that area processed later. 
     As described above, the methodology may be used to prioritize or weight the subsets that are processed later. Therefore, certain areas of the documents can be prioritized for clear zones by controlling the order in which the areas of the image data are processed. For example, returning to the example in which the document is segmented into a grid of 54 blocks and the image data is segment into subsets corresponding to such blocks. The data may be analyzed in an order starting with one of the blocks in the middle of the grid, such as row  3 , column  3 . The segments may be processed in an order that corresponds to moving in a counterclockwise rotation from the original block. In this way, the last blocks to be processed are the blocks corresponding to the trailing edge of the piece and the upper edge of the piece. By analyzing the data in this order, the process prioritizes or weights the trailing edge and the upper edge for the clear zone. Alternatively, the system may prioritize certain areas of the document, such as the upper edge or lower edge. The data may be processed so that the systems factors in the location of the clear zone and not just the size of the clear zone. For instance, the system may process the data and identify several portions of the document each of which has a clear zone having an area that is greater than the area required to print the necessary identification marking. Each such clear zone is a candidate clear zone because it has sufficient length and width on which to print the identification marking, such as a bar code. The system may select which clear zone is the zone on which the identification marking is printed (i.e. which candidate zone is the printing zone). For instance, the printing zone need not be the candidate zone with the largest area. Instead, the printing zone may be selected according to a second criteria. For instance, it may be desirable to weight the printing zone toward being in a particular portion of the document. One example may be to weight the printing zone so that the printing zone is toward the bottom of the document. In this way, the candidate zone that is farthest toward the bottom of the document is selected as the print zone. Similarly, it may be desirable to have the print zone toward the leading edge of the document. In such an instance, the system will select the candidate zone closest to the leading edge as the print zone. Further, other criteria can be used to select the print zone from among a plurality of candidate zones. For instance, the print head is moveable, but it may be desirable to minimize movement of the print head. Therefore, it may be desirable to select the print zone so that movement of the print head is minimized. Accordingly, from a plurality of candidate zones the system may select as the print zone the zone that is most closely aligned with the print head. 
     It will be recognized by those skilled in the art that changes or modifications may be made to the above-described embodiments without departing from the broad inventive concepts of the invention. It should therefore be understood that this invention is not limited to the particular embodiments described herein, but is intended to include all changes and modifications that are within the scope and spirit of the invention as set forth in the claims.