Patent Publication Number: US-2017368846-A1

Title: System and method for automatically adjusting print tray position relative to print head nozzles

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to printing on articles of manufacture, and more particularly to a system and method for printing on multiple different types of articles of manufacture by the same conveyor printing system. 
     Performance improvements in computing, networking and communications has led to enormous advances in the number and types of capabilities that one can achieve using a networked device. For example, in the printing industry, websites such as www.vistaprint.com allow a user of a networked device to select and customize template designs for printed and electronic products, and then to order and purchase quantities of such product(s). As the ability to customize designs for printed products becomes simpler for the end customer, the demand for customized printed designs on different types of products has increased. For example, consumers desire not only printed paper documents such as business cards, postcards, brochures, posters, etc., but also many other types of items such as shirts, hats and other garments, and office tools and promotional items such as rulers, USB drives, calculators, toys, tape measures, etc. 
     As the desire for articles of manufacture such as the promotional items and office tools just described increases, companies looking to print on such products seek ways to meet the demand. Typically, printing on an article of manufacture, especially those that do not comprise a paper product, requires a specialized printing platform (hereinafter “printer tray”) designed to fixedly retain the article of manufacture while a particular design is printed thereon. A blank (unprinted) article of manufacture is loaded onto the specialized printer tray, which in turn is loaded onto a conveyance system of the printing system, which prints the intended design on the article of manufacture. In an industrial environment, manufacturers of printed articles of manufacture typically imprint the same design on a long run of the same type of article of manufacture. This is due in part to the fact that mass production has traditionally been the realm of non-customized unpersonalized products, and further in part due to the high setup time for each print run. In general, in the past, higher efficiencies in terms of time and cost were achieved by printing the same design on high quantities of the same type of article of manufacture. The fewer the quantity of a given type of article of manufacture printed with a given design, the less efficient the process was. 
     Mass customization overturns the traditional model for achieving high efficiencies in printing. For any given type of article of manufacture, there may be as many different unique designs to print as there are quantity of the particular type of article of manufacture. Adding into this mix any number of different types of articles of manufacture, and the traditional model for achieving printing efficiencies is no longer applicable. 
     What is needed is a new printing model which allows any number of unique print designs to be printed on any number of different types of articles of manufacture without interrupting the manufacturing (i.e., “printing”) flow or causing downtime of the printing system. Furthermore, it would be desirable to allow multiple different types of articles of manufacture to be printed in any order in the manufacturing flow. Additionally, it would be desirable to allow insertion of high-priority print jobs into the manufacturing flow without interrupting the flow or causing any downtime of the printing system. 
     SUMMARY OF THE INVENTION 
     Embodiments include systems and methods for a conveyance printing system which prints any number of unique print designs on any number of different types of articles of manufacture in a continuous flow. Embodiments of the invention may further be configured to allow multiple different types of articles of manufacture to be interspersed in a print manufacturing flow in any order and without regard to which type(s) of articles of manufacture are precedingly or succeedingly printed in the flow. 
     Embodiments include systems and methods for imprinting different types of articles of manufacture and for selectively enabling one or more of pre-treatment, processing, and/or post-treatment processes according to the type of article of manufacture to be processed. 
     In an embodiment, a printing system for processing different types of articles of manufacture includes a conveyor system which receives and conveys one or more articles of manufacture from an entry port to an exit port of the printing system, an identifier reader which reads an identifier associated with the one or more articles of manufacture identifying a type of article of manufacture to be printed, a printer configured to receive one or more print jobs and to print the one or more print jobs on the received articles of manufacture, at least one of a pre- and/or post-print-processing treatment unit, and one or more controllers configured to selectively turn on or turn off one or more of the at least one pre- and/or post-print-processing treatment unit based on the value of the type of article of manufacture to be printed as identified from the read identifier. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of this invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
         FIG. 1A  is a top-down view, and  FIG. 1B  is a perspective view of a schematic representation of an exemplary embodiment of a conveyance printing system; 
         FIG. 2A  is a perspective view of a schematic representation of an exemplary embodiment of a tray being loaded with articles of manufacture; 
         FIG. 2B  is an exploded view of the tray shown in  FIG. 2A ; 
         FIG. 2C  is a top down view of a number of different tray inlays configured to hold different types of articles of manufacture; 
         FIG. 2D  is a top down view of the tray of  FIG. 2A  shown without a tray inlay placed therein; 
         FIG. 2E  is a side view of a tray illustrating a horizontal usage orientation and a vertical storage orientation; 
         FIG. 3  is a perspective exploded view and its corresponding assembled view of a schematic representation of an alternative exemplary embodiment of a tray implemented in accordance with the invention; 
         FIG. 4A  is a top perspective view of a schematic representation of an embodiment of a loading station; 
         FIG. 4B  is a front perspective view of the loading station of  FIG. 4A ; 
       FIG.  4 B 1  is a zoomed-in view of a section of the tray rack shown in  FIG. 4B ; 
         FIG. 4C  is a rear perspective view of the loading station of  FIG. 4A  wherein the article of manufacture rack and the tray rack are empty of articles of manufacture and empty of trays; 
         FIG. 4D  is a block diagram of a schematic representation of an exemplary pick-to-light system; 
         FIG. 4E  is a side view of the loading station of  FIG. 4A ; 
         FIG. 5  is a block diagram representation of a computer system which may be used to implement one or more of the conveyance printing system components, such as but not limited to the system controller; 
         FIG. 6  is a view of a schematic representation of an unloading station; 
         FIG. 7A  is a top down view and  FIG. 7B  is a perspective view of a schematic representation of a section of the conveyance system which implements a transverse direction of the forward motion of the conveyor; 
         FIG. 8A  is a side perspective view of a schematic representation of an exemplary embodiment of a pre-treatment system implemented in accordance with the invention; 
         FIG. 8B  is a perspective view of the pre-treatment system of  FIG. 8A  illustrating the entrance of the system; 
         FIG. 8C  is a perspective view of the pre-treatment system of  FIG. 8A  taken from the rear and exit of the system with the housing and conveyor removed; 
         FIG. 8D  is a view of a schematic representation of one of the brush units in the pre-treatment system of  FIG. 8A ; 
         FIG. 9A  is a top perspective view of a schematic representation of an exemplary embodiment of a printer system implemented in accordance with the invention; 
         FIG. 9B  is a top perspective view of the printer system of  FIG. 9A  with the upper framing and housing removed; 
         FIG. 10A  is a view of a schematic representation of the linear motion system within the printing system of  FIGS. 9A and 9B  with a tray engaged thereon; 
         FIG. 10B  is a view of the linear motion system of  FIG. 10B  without the tray; 
         FIG. 11  is a flowchart illustrating an exemplary method for adjusting the height of the tray for printing or other processing; 
         FIG. 12  is a flowchart illustrating the workflow operations of the conveyance printing system; 
         FIG. 13  is a block diagram illustrating a retail production system in which the conveyance printing system may operate; 
         FIG. 14A  is a schematic representation of an example gang template; 
         FIG. 14B  is a schematic representation illustrating the filling of a gang template; 
         FIG. 14C  is a schematic representation of a filled gang; and 
         FIG. 14D  is a top down view of a tray filled with printed articles after the filled gang file of  FIG. 14C  is printed on a filled tray. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention are directed to supporting a new printing paradigm through methods and systems which alone or together allow any number of unique print designs to be printed on any number of different types of articles of manufacture without interrupting the print manufacturing flow or causing downtime of the printing system(s). Embodiments of the invention may further be configured to allow multiple different types of articles of manufacture to be interspersed in a print manufacturing flow in any order and without regard to which type(s) of articles of manufacture are precedingly or succeedingly printed in the flow. Embodiments of the invention may further be configured to allow insertion of high-priority print jobs into the queue of a currently running print manufacturing flow without interrupting the flow or requiring any downtime of the printing system(s). 
     Turning now to the drawings,  FIGS. 1A and 1B  show an exemplary embodiment of a novel continuous-flow conveyance printing system  100  with capability to print on multiple different types of articles of manufacture using the same printer, and to print potentially different image content on every article of manufacture, without requiring the printing system to stop or be taken offline between print jobs or between printing of different types of articles of manufacture. 
     In an embodiment, the continuous-flow conveyance printing system  100  operates to print customized images on promotional goods or items, typically characterized by, but not limited to, metallic and/or plastic surfaces. The continuous-flow conveyance printing system in the illustrative embodiments described herein is a production system for direct digital ink-jet printing on promotional items. The system can process a mixture of different promotional items and each item may be printed with a different design or image. The printed items are sorted and packaged on the system, and in some embodiments, direct shipments may even be processed and packed on the system. 
     In the embodiment shown in  FIGS. 1A and 1B , the continuous-flow conveyance printing system  100  comprises two identically constructed production loops  110   a,    110   b,  which supply and share a printing system  150  via a conveyance system  180 . Of course, it is to be understood that other embodiments of the system may include only one production loop, or alternatively may include three or more such production loops. Each production loop  110   a,    110   b  includes an independent operations area  120   a,    120   b  comprising a loading station  130   a,    130   b  and an unloading station  140   a,    140   b.  The printing system  150  includes a pre-treatment system  160  and a printer system  170 . 
     The Conveyance System 
     As best illustrated in  FIGS. 7A and 7B , which show a small portion of the full conveyance system  180 , including a portion of the main loop  186  and a portion of a transverse motion section  187  which allows a tray to bypass a section of the main loop  188 , the conveyance system  180  includes a conveyor  181  such as a conveyor belt or roller chain(s), conveyor rail(s)  182  for supporting and guiding the conveyor  181 , conveyor drivers  183  for driving the conveyor  181  in at least a forward (and potentially a reverse) motion, a plurality of removable print trays  200  for transporting articles of manufacture through the system  100  (see  FIGS. 1A and 1B ), pneumatic stoppers  184  for stopping movement of a tray  200  being transported on the conveyor  181 , sensors  185  for monitoring the position(s) of the tray(s)  200  on the conveyor  181 , controller(s)  186  for controlling the drivers  183  and stoppers  184  of the conveyance system, and transverse conveyance sections  187  for bypassing the main loop  188  of the conveyor system  180 . 
     The conveyance system  180  transfers the print trays  200  in the two main loops from the loading stations  130   a,    130   b  to the printing system  150  and then on to the unloading stations  140   a,    140   b,  respectively. In an embodiment, the conveyor system  180  is implemented using a heavy duty steel belted conveyor, such as a modular transfer system manufactured by Bosch Automation Technology and Robert Bosch GmbH. Preferably, the conveyance system  180  transfers the trays  200  at a constant working height. For example, in one embodiment, the working height of transport may be 840 mm to provide optimal loading and unloading ergonomics for a standing operator  2   a,    2   b  (referred to generally as  2 ). 
     The position of trays  200  along the conveyance path is determinable based on input from sensors  185 , such as inductive or RFID sensors, positioned at strategic locations along the conveyance path (including the main loop  188  and transverse sections  187 ). Controllable stoppers  184  are positioned at strategic locations along the conveyance path to effect stopping (and controllable releasing) of the forward transport of trays  200  on the conveyor  181  at various predetermined positions along the conveyance path. 
     Trays 
     All articles of manufacture (also referred to herein as “articles”) to be printed are conveyed on trays. Each tray is configured to hold one or more types of articles of manufacture (specific embodiments of which are shown in  FIG. 2A  as  99   a - 99   i ) in respective fixed positions as the tray  200  is conveyed through the system  100 . 
       FIGS. 2A-2E  together illustrate an exemplary embodiment of a tray  200  for use in the system  100 . In the exemplary embodiment, each tray  200  comprises a base plate  201  and a tray inlay  210 , example embodiments of which are shown best in  FIG. 2C  at  210   a,    210   b,    210   c,    210   d  customized for specific articles of manufacture  99   a,    99   b,    99   c,    99   d,  respectively. The inlay  210  of the tray  200  is customized to carry a number of articles of manufacture  99  in dedicated slots  211  for each article  99 . Each dedicated slot  211  of the inlay  210  is configured to consistently and accurately align a specific type of article of manufacture  99  in the tray inlay  210  of a tray  200  for correct print alignment, thereby preventing waste and re-print inefficiencies due to improper article alignment (which can cause printed images to be mis-positioned and/or to appear distorted). The number of articles  99  on a given tray inlay  210  will vary depending on the size of the tray inlay  210 , the size of the article(s)  99 , and other system parameters which affect how the articles may be positioned. For example, in an embodiment, one system parameter is the width of the printable area. In an example, the width of the printable area by the printer system  150  is 72 mm. As best illustrated in  FIG. 2C , all articles  99  are positioned such that the target print area of each article is centered down the center line of the inlay  211 . The number of articles  99  carried by one tray  200  can therefore range from one to many. 
     Preferably, the tray inlay  210  is removable, such that one inlay  210   a,    210   b,    210   c,    210   d  designed to hold a particular type of article of manufacture  99   a,    99   b,    99   c,    99   d,  can be switched out of the tray  200  and replaced by another inlay  200  designed to hold a different type of article of manufacture  99 . In an embodiment, each type of tray inlay  210   a,    210   b,    210   c,    210   d  is designed to fit within a tray frame  220 , which is universal to all types of inlays  210   a,    210   b,    210   c,    210   d.  The tray frame  220  may literally be a frame which encases the outer side surfaces of the inlay  210 . (See, for example, frame  250  in  FIG. 3 , which illustrates an alternative example embodiment  200   b  of a tray  200  which can be used in system  100 ). In such embodiment, the frame  220  includes an orifice that substantially conforms to the shape and size of the outer edges of the tray inlay  210  when the tray inlay  210  is placed flat within the frame with the slots  211  facing up and ready to receive articles of manufacture  99  to be printed. 
     Alternatively, the tray frame  220  may include only one or more frame side members  220   a,    220   b,    220   c  which are configured to encase only a portion of the outer side surfaces/edges of the inlay  210 . For example, in an embodiment, the tray frame  220  comprises a main frame member  220   a  positioned along or near one edge of the base plate  201  and having two sub-members  220   b,    220   c  perpendicularly arranged along or near the transverse edges of the base plate  201 . The perpendicularly arranged sub-members  220   b,    220   c  may be connected at one end to respective opposite ends of the main frame member  220   a.  The inner surfaces of the main frame member  220   a  and perpendicularly arranged sub-members  220   b,    220   c  engage three of the outer edges of the inlay  210 , providing both support and alignment assistance for the inlay  210  with respect to the frame  220 . In addition to, or instead of the embodiments described herein, the frame  220  may take other forms. For example, in an exemplary embodiment, the tray includes a handle  280  which allows the operator  2  to manipulate the tray  200 , for example when inserting or removing the tray  200  into a tray rack lane  135  (discussed hereinafter), or when flipping the tray from a vertical position to a horizontal position for use, or vice versa for storage (also discussed hereinafter). 
     In an embodiment, the tray  200  is designed to position the target print surface of the article(s)  99  loaded in the tray inlay  210  of the tray  200  at a constant height as the tray is conveyed along the conveyor  181  regardless of the specific type of article of manufacture  99  that is loaded in the tray  200 . For example, in one embodiment, each type of inlay  210   a,    210   b,    210   c,    210   d,  is configured to position the target print surface(s) of any articles of manufacture  99   a,    99   b,    99   c,    99   d  loaded therein to be within a known distance of the known height of the print head nozzles when the tray is conveyed through the printer system  170 . For example, if the known height of the print head nozzles in the printer system  170  is 81 mm above the conveyor which passes under the print head(s) in the printer system  107 , the inlays  210  may be configured such that print surface(s) of the articles of manufacture  99  when loaded on the tray  200  have a height of 80 mm when the tray is mounted on the conveyor running under the print head(s). 
     In one embodiment, a constant print surface height across all types of inlays  210   a,    210   b,    210   c,    210   d,  is achieved by way of one or more vertical positioning spacers  203   a  positioned between the base plate  201   a  and the inlay  210   a.  Different types of inlays  210  may use positioning spacers  203  of different heights, as controlled by the shape and size of the particular article of manufacture  99   a,    99   b,    99   c,    99   d  for which the particular inlay  210   a,    210   b,    210   c,    210   d  was designed to carry. 
     In one tray design, for example as best illustrated in  FIGS. 2A, 2B and 2E , the vertical positioning spacers  203  attach at one end to the base plate  201  and at the other end to the underside of the inlay  210  by way of screws or bolts. In an alternative tray design, for example as illustrated in an alternative tray embodiment  200   b  in  FIG. 3 , the tray inlay  240  includes a slotted plate  242  having slots  241  which conform to an outer shape of a cross-section of the articles of manufacture for which it is designed to hold. The slotted plate  242  is mounted over a support plate  243 , which is configured to support the articles of manufacture  99  loaded therein such that the printing surface(s) of the loaded articles is maintained at a predetermined height relative to one or more points on the tray, while also preventing the articles loaded thereon from falling through the respective slots  241 . In one embodiment where the articles to be loaded thereon are flat and thin, the support plate  243  may be a flat solid sheet of material with orifices embedded therein whose shapes correspond to the shapes of the outer edges of the articles of manufacture. In other embodiments, where the articles of manufacture to be loaded on the inlay  240  varies in shape in the 3 rd  dimension when the print surface of the article is flat and constant along a plane parallel to the plane defined by the 1 st  and second dimensions defined by the flat surface of the inlay, the support plate  243  may include molded cavities which conform to the shape(s) of the portion(s) of the articles of manufacture that are to be supported by the support plate  243 . The height requirement for the print surface(s) of the articles of manufacture may be achieved by shaping the molded cavities and slots so as to fix the article of manufacture  99  in a position such that the target print surface(s) of the article are at the required height relative to one or more points on the tray. Alternatively, the required height of the print surfaces of the loaded articles may be achieved by affixing vertical positioning spacers  233  to the bottom of the inlay  240 . When vertical positioning spacer(s)  233  are used, the height of the spacers  233  are chosen such that the height of the target print surface(s) of the articles of manufacture  99  mounted thereon meet the height requirements. 
       FIGS. 2A-2E and 3  together illustrate a plurality of exemplary trays, each for holding a different type of article of manufacture  99 . As illustrated, each tray inlay  210   a,    210   b,    210   c,    210   d,    241  is designed specifically to hold one or more specific types of articles of manufacture such that the print surface(s) of the held articles of manufacture are at a specific height relative to the conveyor belt. Since different articles of manufacture have different thicknesses and shapes, in general each type of article of manufacture will have a corresponding different tray inlay specifically designed to hold that particular type of article of manufacture. In a preferred embodiment, the tray frame is 250 mm square, and each inlay is configured to hold one or more articles of manufacture positioned such that when the tray  200  is conveyed through the printing sys  150 , the target print surfaces area positioned down the center line of the available printable width of the print system  170 . 
     In an embodiment, each tray is identified with an identifier  230  from which information needed to process the tray  200  and/or the articles of manufacture  99  loaded thereon can be read or derived. Various detectable identifiers are known in the art and any detectable identifier can be used to implement the tray identifier. In one embodiment, the identifier  230  is a Radio Frequency Identification (RFID) tag, and is identified by an RFID reader, positioned along the conveyance path, in combination with a controller. In another embodiment (not shown), the identifier  230  is a barcode which is detected by a barcode reader. In yet another embodiment (not shown), the identifier  230  is a Near Field Communications (NFC) tag which is detected by an NFC tag reader. The tray identifier  230  may be variously embodied using other technologies now known or developed in the future. The tray identifier  230  is used to extract various items of information needed to process the articles of manufacture  99  correctly through the system  100 . 
     The Operations Area 
     Returning to  FIGS. 1A and 1B , each independent operations area  120   a,    120   b  is configured to allow one or more operators  2  (shown as  2   a  and  2   b ) to fill empty trays  200  with unprinted articles of manufacture  99  (such as, but not limited to, promotional items) and to send loaded outgoing trays  200  out onto the conveyance system  180  for conveyance to the printing system  150 , unload printed articles from trays incoming from the printer, and scan, sort and package the printed articles. In an embodiment, the operators  2  are human, but in other embodiments, one or more tasks performed by the human operators  2  may be automated, for example through automated machinery and/or use of robotics. 
     Loading Station 
       FIGS. 4A, 4B and 4C  illustrate an exemplary embodiment of a loading station  130  which may be used in connection with the operations area(s)  120   a,    120   b  of the system. The loading station  130  includes a flow rack  131  for storing, and delivering to the operator  2 , blanks (unprinted) of the various types of articles of manufacture  99  to be printed by the system  100 . In an embodiment, the flow rack  131  comprises a plurality of lanes, referred to hereinafter as blank article lanes  132   a,    132   b, . . . ,    132   m,  (or simply  132 ) which are loaded and filled from the back of the rack  131  (shown in  FIG. 4C ) and pulled out and removed from the front of the rack  131  (shown in  FIGS. 4A and 4B ). The blank article lanes  132  are preferably configured to be tilted downward toward the front of the rack  131  at an incline (angle β) so that as article blanks  99  are removed at the front of the rack  131  from a blank article lane  132  for loading into a tray, the remaining article blanks  99  in the lane slide forward toward the front of the lane due to the operation of gravity. This allows for easy access by the operator  2  loading the trays  200 . In an embodiment, articles of manufacture  99  are packaged in bulk in boxes  98 . When a blank article lane  132  is loaded with a particular type of unprinted article of manufacture  99 , one or more bulk-pack boxes  98  are opened and placed in a lane  132  which is dedicated to that particular type of article of manufacture. The box(es)  98  are preferably loaded from the back of the rack. As box(es)  98  are emptied and removed from the lanes  132 , the remaining box(es) slide forward and down the incline of the lane  132  via gravitational pull. 
     Every type of article of manufacture  99  (e.g., each different type of promotional article  99   a,    99   b,    99   c,    99   d ) has one or several dedicated blank article lane(s)  132   a,    132   b, . . . ,    132   m.    
     The blank article lanes  132  may be organized on one or more multiple levels. In the embodiment shown in  FIG. 1 , the blank article lanes  132  occupy two levels  131   a,    131   b,  with multiple lanes  132  on each level. 
     In an embodiment, the flow rack  131  includes at least one (as shown) or multiple (not shown) interstage lane  133  configured with a reverse inclination (at angle a) towards the back of the flow rack  131 . The interstage lane  133  is used to gravitationally transport empty raw material boxes  98  from the front of the flow rack  131  to the back of the flow rack  131  for collection and transport outside of the operations area  120 . 
     The loading station  130  also includes one or more tray rack(s)  134  for storing empty trays  200  ready to be filled with blank articles of manufacture  99 . In a preferred embodiment, the tray rack  134  is stacked below the blank article rack(s)  131   a,    131   b.  As explained in detail above, each tray  200  includes an inlay  210  configured to hold a particular type of article of manufacture  99  (such as a promotional item). The inlay  210   a,    210   b,    210   c,    210   d  for each type of article  99   a,    99   b,    99   c,    99   d  may be different. Preferably, the tray rack  134  includes a plurality of lanes, called tray lanes  135   a,    135   b, . . . ,    135   n,  referred to generally as  135 , located underneath and in positional correspondence to various ones of the blank article lanes  135   a,    135   b, . . . ,    135   m  of the flow rack. In this embodiment, trays  200  having inlays  210  configured to hold a particular type of article  99  are preferably stored in a tray lane  135  directly beneath a corresponding respective blank article lane  132  dedicated to the specific type of article of manufacture  99  that the tray inlay  210  is configured to hold. 
     In an embodiment, the trays  200  are stored in the tray lanes  135  standing on one side. This allows more trays  135  to be stored in the tray rack  134  per lane  135 .  FIG. 2D  best illustrates the desired tray orientation for storage (vertical) and for active use (horizontal). The trays  200  are stored in vertical orientation (up on one side) in their tray lanes and are flipped horizontal by the operator  2   a  prior to being loaded with blank articles of manufacture  99  of the type for which the inlay  210  of the tray  200  has been designed to hold. During loading, the conveyance system  180  is configured to allow the tray  200  to rest on the conveyor rails  182  without being conveyed forward. After loading the tray  200  with blanks  99 , the operator  2   a  releases the tray  200  to be conveyed forward by the conveyance system  180  for print processing. During unloading, the conveyance system  180  is configured to allow the tray  200  to rest on the conveyor rails  182  without being conveyed forward. After the operator  2   b  removes the printed articles from the stopped tray  200 , the operator flips the tray from the horizontal position to the vertical position, as illustrated in  FIG. 2D . 
     Returning to  FIGS. 4A-4D , the blank article rack  131  and tray rack  134  are preferably positioned adjacent the conveyance system  180  and in particular such that the blank article lanes  132  and tray lanes  135  open onto the conveyor  181 . This allows an operator  2   a  standing in front of the racks  131  and  134 , and in particularo, in front of the openings of the lanes  132 ,  135 , with the conveyor  181  passing therebetween, to easily select and ergonomically remove a tray  200  from a tray lane  135  and place it onto the conveyor  181  in one easy motion, load the tray  200  with articles  99  removed from the blank article lane  132  above the selected tray lane  135 , and release the tray  200  for transport by the conveyance system  180 . In an embodiment, the tray rack  134  is positioned and/or stacked below the flow rack  131  such that the bottoms of the openings of the tray lanes  135  are the same height as the conveyor rails  182 . In an exemplary embodiment, the height of the conveyor rails off the floor is 840 mm, and the width of the conveyor  181  (and including outside width of the conveyor rails) is 250 mm. The height off the floor of the bottoms of the openings of the lower row of tray lanes  131   a  is 1150 mm. The height and width of the conveyor, and the heights and setup of the tray and articles racks, are designed for optimal loading ergonomics. As best seen in  FIG. 4E , the operator can therefore stand in an upright position (i.e., with optimal posture), and, without extending or raising the upper arm(s) or moving the upper body or shoulders, reach across the conveyor to grasp a tray  200  from a tray lane  135 , pull it out of the tray lane  135 , and lay it horizontal into the loading position on the conveyor  181 . 
     In an embodiment, the loading station  130  includes one or more indicators  136  to indicate which type of articles of manufacture  99  are to be loaded onto corresponding trays  200 . In an embodiment, the loading station is configured with an indication panel  190  having one or more indicators  136  corresponding to each tray lane  135 . In this embodiment, trays  200  queued in the tray lane  135  are dedicated to a particular type of article of manufacture  99 . Thus, all trays  200  stored in the particular tray lane  135  are configured with an inlay  210  which is designed to hold the particular article type for which the tray lane is dedicated. When the indicator  136  of a particular tray lane  135  indicates that a tray  200  in its lane should be loaded, the operator removes a tray  135  from the indicated lane, removes one or more articles  99  from the corresponding blank article lane (which are of the type for which the inlay  210  of the selected tray  200  was designed), and loads the tray  200  with the selected article(s)  99 . 
     In an alternative embodiment (not shown), the loading station  130  is configured with one or more indicators  136  corresponding to each blank article lane  132 . In this embodiment, when an indicator  136  associated with a blank article lane  132  indicates that a tray  200  should be loaded with articles  99  of the type contained in the indicated lane  132 , the operator  2   a  removes a tray  200  from a tray lane  135  corresponding to the indicated blank article lane (which contains trays of the type configured to hold the indicated article type), removes one or more articles  99  from the indicated blank article lane  132 , loads the selected tray  200  with the selected article(s)  99 , and launches the loaded tray  200  for print processing by releasing the tray  200  onto the conveyance system  180 . In an embodiment, the conveyance system  180  includes stoppers  184  which automatically stop a tray in front of the loading station  130 . The stopper  184  is manually disengaged by the operator  2   a  at a puch of a button. 
     In a specific embodiment, illustrated in  FIG. 4D , the indicators  136  are implemented in what is herein termed a “pick-to-light” system, or light indicator panel  190 . The pick-to-light system  190  supports the operator in picking the correct trays  200  from the tray rack  134  and/or articles  99  from the blank article rack  131 , and shortens the reaction time of the operators  2  to increase operations efficiency. In an embodiment, each indicator  136  comprises one or more lights, such as LEDs, that turn on, turn a specific color, and/or flash in a particular sequence, when the tray lane  135  (and/or a blank article lane  132 ) is to be selected by the operator. A controller  195  controls the turning on and off of the indicators. The controller  195  is configured with intelligence as to what type of trays  200  are stored in each tray lane  135  and/or what types of articles of manufacture are in each blank article lane  132 . The controller  195  is further configured to be in communication with the system controller  105  and/or production server  101  to receive information as to what type of tray  200  is to be loaded next in the production process. In one embodiment, as best illustrated in  FIG. 4D , the pick-to-light system  190  includes one yellow  191   a,    191   b, . . . ,    191   n,  and one green  192   a,    192   b, . . . ,    192   n,  light signal for each lane of the tray rack. The light signals can have the following states: 
     
       
         
           
               
               
               
             
               
                   
               
               
                   
                 Yellow Light 
                   
               
               
                 Green Light State 
                 State 
                 Signal Meaning 
               
               
                   
               
             
            
               
                 Steady On 
                 Off 
                 Current article type to print. Load 
               
               
                   
                   
                 predetermined number of trays. 
               
               
                 Blinking On 
                 Off 
                 Current article type to print.  
               
               
                   
                   
                 Load single tray. 
               
               
                 Steady, Blinking  
                 Steady On 
                 Next article type to be printed  
               
               
                 or Off 
                   
                 will be on this tray. 
               
               
                 All lanes 
                 All lanes 
                 A warning signal. Check the  
               
               
                 simultaneously 
                 simultaneously 
                 display screen 
               
               
                 blinking 
                 blinking 
                 for details. 
               
               
                 Off 
                 Blinking 
                 Emergency-Stop button  
               
               
                   
                   
                 has been pressed on 
               
               
                   
                   
                 the system. 
               
               
                   
               
            
           
         
       
     
     In and embodiment, the loading area  120  includes a tray identifier reader  138 , such as RFID or barcode reader, which scans the tray identifier  230  associated with the tray  200  prior to, during, or after loading of the blank articles into the tray  200 . The scanned tray identifier  230  (or signal or other information from which the value of the tray identifier can be derived) is sent to the system controller  105 , which in one embodiment is in communication with a production server  101  which matches the scanned tray identifier  230  with a particular print job as will be discussed in further detail hereinafter. The print job can be a single print job or an aggregate print job containing multiple individual print jobs. When the print job is an aggregate print job containing the one or more designs which are to be simultaneously printed on multiple respective articles loaded in the tray  200 , the production server  101  also associates the position of each article in the tray with a corresponding customer order. 
     In an alternative embodiment (not shown), each slot  211  in the tray inlay  210  is configured with an identifier, such as an RFID tag, a barcode, etc. An identifier reader, such as RFID or barcode reader, scans the identifier associated with each tray inlay slot prior to, during, or after loading of the printed article in order to associate the article of manufacture  99  directly with a customer order. 
     The loading station  130  may include one or more control screens  139  which function as a communication interface between the system controller  105  and/or production server  101  and the load operator  2   a.  System status, the required trays, warnings and other information may be displayed on the screen to convey information to the operator  2 . 
     Unloading Station 
     As best illustrated in  FIGS. 1A, 1B and 6 , the unloading station  140   a,    140   b,  referred to generally as  140 , preferably includes an identifier reader  148 , a display or control screen  149 , an order summary printer  141 , a labeler  142 , and a packaging system  143 , and may further include a sorting and packing table or station  144 , a shipping label maker  145 , and a postage machine  146 . The unloading station  140  is operated by one (or more) operator(s)  2   b.  In an embodiment, the load operator  2   a  and the unload operator  2   b  are different people. Furthermore, there may be more than one load operator  2   a  and/or more than one unload operator  2   b  to perform the load and unload functions. In an alternative embodiment, the load operator  2   a  and the unload operator  2   b  may be the same person. The purpose of the unloading station  140  is to assist an operator  2   b  to unload articles  99  from a tray  200  arriving from the printing system  150 , to collect the processed articles  99  associated with each customer order, to generate and/or receive an order summary form, to package the individual articles associated with the individual customer order(s), and to bundle the packaged individual articles of each customer order into one or more shipment units. In an embodiment, the unloading station  140  may also include an area for packaging the shipment units into shipping packages, applying shipping labels and postage for sending the packages out for shipping. 
     In an embodiment, the identifier reader  148  scans the tray identifier  230  of each tray  200  arriving from the printing system  150 . The identifier reader  148  may be mounted along the conveyance system  180  in a position to read the identifier of each incoming tray  200 , or may be a hand scanner (not shown) operated manually by the unload operator  2   b.  The scanned identifier  230  is communicated to the controller  105  or to the production server  101  or other control system, which matches the scanned identifier to one or more customer orders associated with the printed articles  99  in the tray  200 . The control screen  149  displays for the operator  2   b  an indication of which printed article(s)  99  should currently be removed from the scanned tray  200  for packaging and processing. The control system  105  or production server  101  then automatically generates an order summary associated with the customer order and signals the order summary printer  141  at the unload station  140  to print the order summary and the labeler  142  to print one or more labels associated with and identifying the removed article(s)  99 . The label(s) may be applied directly to the removed article  99  or alternatively to the packaging for the article(s). In an embodiment, the unload station includes a packaging system, such as an automated bagger  143 . In an embodiment, the order summary form and one or more of the printed article(s) associated with the particular customer order are input to the automated bagging system  143  and the label(s) are applied to the bag(s). In an embodiment, the bagging process by the automated bagger is triggered by a touch switch operated by the unload operator  2   b.  However, in an alternative embodiment, the bagging may be performed automatically without operator assistance or input. 
     Preferably, the unload operation is guided by a pick-to-screen process. The control screen  149  at the unloading station  140  indicates the number and the position of the articles  99  on the trays  200  that belong to the same customer order and are to be put together in one bag. In an embodiment, the identifier reader  148  is a RFID reader and is used to scan the RFID tray identifier  230 . In an alternative embodiment, the identifier reader  148  is a hand scanner which is used by the unload operator  2   b  to scan the identifier corresponding to a respective slot on the tray to identify which of the printed articles on a given tray is being unloaded by the operator. The information is used by the production server  101  or system controller  105  to command the order summary form printer  141 , automatic bagger  143 , and label printer  142 . 
     At the sort/pack table  144  the bags are collected. The bags are scanned, sorted, and in case of direct shipments the bags are packed in cardboard boxes. Automatically printed labels are applied to the boxes. 
     Operator Operations and Ergonomics 
     The construction and placement of the loading and unloading stations and conveyance system are designed with particular attention to operator ergonomics and time operating efficiency. Referring to  FIG. 4E , the height of the tray rack lanes  135  and conveyor  181  passing in front of the tray rack  134  is preferably approximately hip-high for an average human operator. In an embodiment, the conveyor height is 840 mm above the floor on which the operator stands. This allows the human operator  2   a  to stand upright with good posture with minimal movement of the upper arms and shoulders when handling the trays incoming form the printing system  150 , flipping the trays  200  from a horizontal position to a vertical position, and returning empty trays  200  to the tray rack  134 . On the load side, the operator  2   a  can also perform the operations of removing trays  200  from the tray rack  134 , flipping the removed trays from a vertical to a horizontal position, loading the trays  200  with articles of manufacture  99 , and releasing the loaded trays to the conveyance system  180  while standing in an upright position and requiring little to no body movement other than lower arm and hand movement. 
     In addition to the construction and placement of the loading and unloading stations and conveyance system, in embodiment, the trays  200  are also designed with particular attention to operator ergonomics. As best seen in  FIGS. 2A, 2B, 2C and 2E , in an embodiment, a slide rail  221  is configured along at least the front edge of the frame  220 . The slide rail  221  is preferably manufactured using a low-friction material such as hard plastic which facilitates a sliding movement along the rails  182  of the conveyance system  180  when in the loading and unloading areas of the system  180 . The front edge of the frame  220  may be identifiable as the side of the frame, when the frame is oriented horizontally, that is situated in front along the forward direction of transport of the conveyance system, as illustrated in  FIG. 2D . As also illustrated in  FIGS. 2B and 2D , the slide rail  221  may be configured with a concave cavity  222  to provide a gripping hold for an operator&#39;s fingers. The front of the frame  220  may also include a handle  280  to allow the operator to grasp the edge of the tray nearest the operator and to flip it from the vertical position to the horizontal position, or from the horizontal position to the vertical position (see  FIG. 2D ) with one hand and with one simple hand movement. 
     As best seen in  FIGS. 2C, 2E, 4A, 4B and 6 ), when the trays  200  are stored in the tray rack  134 , they are placed vertically with the slide rail  221  engaging the floor of the tray rack lane(s)  135  in which they are inserted. The slide rail  221  protects the side of the frame  220  when it is stored in the vertical orientation in the tray rack  134 . In an embodiment, the slide rail  221  is made of a hard plastic with a low friction factor that allows the trays to slide easily along the floor of the lanes  135  in the tray rack  134 . 
     The Printing System 
     Pre-Treatment Station 
     For some types of articles of manufacture  99 , it may be important to clean and/or pre-treat the articles before the actual printing. Referring back to  FIGS. 1A and 1B , a preferred embodiment of the system  100  includes a cleaning and pre-treatment station  160 . The conveyance system  180  is configured to transport trays  200  from the loading station  130  to the pretreatment station  160  prior to moving on to the printer system  170 . 
     As best seen in  FIGS. 8A and 8B , the pre-treatment station  160  includes a framed housing  161  which encloses and/or houses the pre-treatment and cleaning components required for pre-treating and cleaning the print surfaces of the articles of manufacture  99  on trays  200  as the trays  200  pass through the system  160 . In the illustrated embodiment, the two different process fluids (e.g., the wetting agent and the cleaning solution) are supplied from respective canisters  309   a,    309   b  situated under the station&#39;s housing. A third canister  309   c  may be used to collect excess process fluid that accumulates inside the station  160 . Electronic detectors continuously check the level of fluid inside the three canisters. An electrical control cabinet  162  housing the pre-treatment station electronics, and an exhaust air pump/filter  163  may be situated at the top section of the housing. 
     In an embodiment, the pre-treatment station  160  is situated before the entrance to the printer system  170 . The main conveyor belt  180  of the conveyance system  180  passes through the pre-treatment station  160 . However, since the main conveyor speed may be higher than that needed to ensure effective pre-treatment of the print surfaces, the pre-treatment station  160  may be configured with a secondary slower-speed slide-belt system which engages the trays  200  as they pass through the station  160  to slow down the trays as they pass therethrough for increased pre-treatment and cleaning effectiveness. In such embodiment, the main conveyor  181  continues to run but slides under the trays  200  instead of carrying them. 
     In an embodiment, the pre-treatment station  160  applies a two-step treatment process. The first step is the application of a wetting agent which is used to prevent or reduce reticulation of the ink when applied to the surfaces of the articles of manufacture. Ink reticulation can occur when the surface tension of the ink is higher than the surface tension of the material on which it is deposited, and thus the ink droplets retain their surface tension and thus do not fully spread out. Under a microscope, reticulated ink may appear as a mosaic of similar size irregular polygonal shapes, and veins or cracks in the printed image may be visible to the naked eye. 
     A wetting agent may be applied to the print surface of the articles of manufacture. Wetting agents operate to change the properties of the print surface to make it more wettable by increasing the surface energy of the material on which the ink is to be applied to a level at or higher than the surface tension of the ink, triggering the flattening out of the ink droplets and the tendency of the ink to more uniformly spread out and stick to the print surface of the article of manufacture. The type of wetting agent that is effective for a given type of material generally varies depending on the chemical properties of both the ink and the print surface material of the article of manufacture on which the ink is to be deposited. Although the pre-treatment station  160  is shown with one wetting agent applicator, the pre-treatment station  160  may alternatively be implemented with multiple different wetting agent applicators, each for applying a different type of wetting agent on different types of articles of manufacture with different surface material composition. 
     The second step of the pre-treatment process is the cleaning process for smoothing out the wetted print surface and to reduce the surface complexity of the print surface for achieving improved print quality. In one embodiment, the cleaning agent is a diluted isopropyl alcohol (IPA) solution. 
     In an embodiment, the pre-treatment station  160  includes an identical pair of motorized sword brushes applying two different treatment fluids. The first brush unit is the pre-treatment brush which is used to apply the surface pre-treatment fluid or wetting agent. The second brush unit is the cleaning brush which may apply a cleaning solution and brush off or remove excess pre-treatment fluid to perform a final cleaning/de-greasing of the surface. A fluid regulator and filter unit  308   a,    308   b  for each brush is situated outside the station&#39;s housing. 
     In the embodiment shown herein, and as best seen in  FIG. 8C , the pre-treatment fluid and the cleaning fluid are applied in successive stages by two respective identical brush units  300   a,    300   b  contained within the pre-treatment station  160 , one of which is diagrammed in  FIG. 8D  at  300 . In an exemplary embodiment, and as best viewed in  FIGS. 8C and 8D , the brush units are implemented using, for example, a Model KSB111 combination sword brush unit, manufactured by Wandres. A continuously rotating brush belt  301  is height adjusted on a pair of adjustment frames  307   a,    307   b  to touch the target print surfaces of the articles of manufacture  99  with the correct contact pressure as they pass under the belt  301 . The rotating brush  301  may be backed by an inflated cushion  302  (i.e., a pressure buffer) which regulates the contact pressure between the brush  301  and the print surface of the articles of manufacture  99 . An integrated spray unit  304  continuously moistens the brush  301  with the process fluid. A suction unit  305  is also attached downstream from the brush  301  to collect particles and keep the brush itself clean. 
     As described earlier, in an embodiment, all trays  200  are designed to align the target print surface of the various types of articles of manufacture  99  on the trays  200  at an equal (and predetermined) height. In an alternative embodiment, the target print surfaces of the articles of manufacture  99  may not be predetermined, and may in practice vary depending on the type of article of manufacture. In such embodiment, the height of the conveyance may be adjusted within the printing system  150 , such that the target print surfaces are positioned at a predetermined distance from the various processing components (such as, by way of example and not limitation, the pre-treatment system brushes, the print head nozzles, the curing lamps, etc.). The height adjustment can be determined using the principles and system described hereinafter with respect to the height adjustment system  400  in the printer system  170 , and as described in connection with  FIGS. 10A and 10B . 
     In an embodiment, the pre-treatment station  160  includes an identifier reader  164  which reads the identifier  230  of the tray to determine the type of article of manufacture  99  carried by the tray  200 . A programmable logic controller PLC  303   a  controls a 2-level pneumatic height adjuster  303   b  to selectively apply or skip the brush treatment depending on the type of article of manufacture on the tray. The pre-treatment station  160  is depicted in the exemplary embodiment as having a single wetting agent application system  300   a  and a single cleaning solution application system  300   b.  In alternative embodiments, the pre-treatment station  160  may implement any number of different wetting agent application systems and/or cleaning agent application systems. The type of wetting agent and/or cleaning agent(s) to apply can be programmed and associated to a particular print job by including instructions or process identifications in the information associated with the tray identifier. When the tray  200  enters the pre-treatment station  160 , a tray identifier reader may read the tray identifier, look up the information associated with the tray identifier, and determine whether and which pre-treatment agents and/or cleaning agents to apply to the print surfaces of the articles of manufacture on the particular tray  200 . 
     Printer System 
     In an embodiment, as best shown in  FIGS. 9A and 9B , the printer system  170  is designed to physically interface with the conveyance system  180  and to communicate with the system controller  105  and/or the production server  101  (see  FIGS. 1A and 1B ). The printer system  170  is preferably mounted within a frame  171 , preferably enclosed for purposes of safety and cleanliness. In an embodiment, the frame  171  includes an inner frame on which the printer itself is mounted, and a guard frame which acts as a cover for the entire system  170 . The inner frame is preferably made from mild steel box section for rigidity which is very important for maintaining a crisp printed image. The guard frame is preferably made from aluminium extrusion in-filled with clear polycarbonate panels. The guards covering the in-feed and out-feed conveyor sections are also made from the same fabricated polycarbonate sheet. 
     The trays  200  enter the printer system  170  immediately after exiting the pre-treatment station  160 . In an embodiment, the trays  200  are engaged with a precision linear motion system  400  for printing. 
     The printer system  170  may include an ionization unit  174  which generates pressurized ionized air aimed at the print surfaces for removing any static charge, both positive and negative, from the print surfaces of the articles of manufacture on the tray. 
     The printer system  170  may further include a plasma jet treatment system  175  which operates to roughen the print surfaces of the articles of manufacture  99  on the tray  200  in order to increase surface tension to achieve better wetting. The plasma jet treatment is used to change the surface energy of the articles of manufacture. In an embodiment, the ink used is UV ink, which has higher viscosity than water-based ink. The surface energy is measured in Dynes and to help the ink adhere to the product, the surface energy needs to be increased to approximately 20 Dynes greater than that of the UV ink. In an embodiment, the plasma jet treatment system  175  includes one or more plasma nozzles set at pre-determined heights above the print surface of the articles of manufacture. Depending on the type of article of manufacture to be treated, the height of the plasma nozzles may be automatically adjusted. 
     In an embodiment, the printer system  170  includes one or more inkjet printer head(s)  70  designed to apply ink colors Cyan, Magenta, Yellow and Black (CMYK). In a particular embodiment, the print width is up to 72 mm. The printheads  70  are affixed to corresponding printhead assemblies, which include a head mounting plate with ink nozzles, ink tanks, head drive control circuits, and an outer housing. 
     In an embodiment, the printer system  170  includes a sensor  402  which senses a parameter from which the height of the printing surface of the articles of manufacture  99  on the tray  200  within the printer system  150  can be determined. Thus, the relative distance between the nozzles  72  of the print head  70  and the printing surface of the articles of manufacture in the tray can be determined. In an embodiment, the sensor  402  is a laser sensor that is mounted in a fixed position on the printer frame  171  above the conveyor  181  at the location that the tray  200  enters the printer system  170 . The sensor  402  measures the distance between the sensor head and the print surface of the articles of manufacture  99  as they pass by a fixed location on the conveyor  181 . The laser sensor measurement is used as input to a tray height adjustment mechanism  403  which adjusts the vertical position of the tray  200  from its unadjusted vertical position as delivered by the conveyance system  180  to a height-adjusted position during the actual printing process by the print head(s)  70 . A controller receives and translates the laser signal from the sensor  402  into parameter representative of an unadjusted vertical position of the print surface of the articles of manufacture  99  on the tray  200 , and determines a tray height adjustment parameter which may be used to signal a tray lift controller  404  to adjust the vertical position of the tray lift  403  so as to position the print surfaces of the articles of manufacture  99  to a vertical height that is within a specified distance (with a range of tolerance) of the print head nozzles  72  when the tray  200  passes beneath the print head(s)  70 . Based on the laser sensor measurement, the height of the printing surface of the articles of manufacture is used to adjust to the optimal printing distance. If an article of manufacture  99  is not correctly placed on the tray  200 , the tray  200  can be rejected without print. Otherwise, the articles of manufacture  99  on the tray  200  are printed. 
       FIGS. 10A and 10B  illustrate an exemplary linear motion system  400 . The linear motion system includes an engagement plate  410  configured to engage a tray  200  when the tray enters the printer system  170  by delivery of the main conveyance system  180 . The engagement plate  410  is slidingly mounted on, or otherwise slidingly attached to, a linear motion transport rail  460 . A driving mechanism  462  (directly or indirectly) engages the engagement plate  410  and is configured to transport the engagement plate  410  along a horizontal plane  465  between a pick-up position  468  at one end A of the rail  460  and a release position  469  at the opposite end B of the rail  460 . In an embodiment, the driver  462  includes a conveyor chain driven by a motor. At the pick-up position  468 , the engagement plate is configured to engage a tray  200  delivered by the conveyance system  180 , and the driver  462  is configured to transport the tray  200  in a forward direction along a fixed linear path  465  defined by the rail  460  to the release position  469 , where the tray  200  is released back to the main conveyance system  180 . After delivering the tray  200  back to the main conveyance system  180 , the engagement plate  410  is driven, by the driver  462 , back along the linear path  465  to the pick-up position  465  to be ready to pick up another tray  200 . The driver  462  thus drives in a forward direction and a reverse direction. 
     The engagement plate  410  includes an engagement mechanism for fixing the tray  200  in static position with respect to the plate  410 . In an embodiment, the engagement mechanism comprises one or more positioning pins  412 . The tray  200  includes positioning sockets or holes  202  in the base plate  210  of the tray  200 . When the main conveyor  181  delivers the tray  200  to the printer system  170 , the tray is automatically transported to and stopped at a position over the engagement plate  410  such that the engagement pins  412  align with the positioning sockets or holes  202  in the bottom of the base plate  210  of the tray. In an embodiment, a tray sensor  450  is mounted on the rail  460  (or alternatively a position on the frame  171  or other mounting substrate within the printing system  150 ). The tray sensor  450  detects the presence of a tray  200  at the pick-up position  468 . The tray is stopped in the pick-up position by a stopper  440 , preferably mounted along the rail  460 . The stopper  460  stops the tray in a position of alignment such that the positioning pins  412  of the engagement plate  410  align with the sockets/holes  202  of the base plate  210  of the stopped tray  200 . A lift controller  430  monitors the sensor signal to perperly control the timing of a lift  420 . The lift  420  operates to lift the engagement plate  410  to simultaneously engage the bottom of the base plate  210  of the tray  200  and center the engagement pins  412  in the positioning sockets/holes of the base plate  210  of the tray, thereby fixing the tray in place on the engagement tray  410 . 
     The lift controller  430  further receives information, directly or indirectly through one or more additional controllers and transmitters and/or receivers, from the height adjustment sensor  402  of the printer system  170 . The received sensor information is used by the lift controller  430  to control the lift  420  to set the height of the engagement plate  410  to a vertical position such that the print surface(s) of the article(s) of manufacture on the engaged tray  200  within a predetermined distance (plus or minus a predetermined tolerance) of the print head nozzles of the print heads  70  of the printer system  150 . 
       FIG. 11  depicts an exemplary embodiment of a method for adjusting the height of a tray to align the print surfaces of the article of manufacture to be printed to with a pre-determined distance of the print head nozzles when the tray  200  on which the articles are carried is printed. As illustrated, a tray approaches the height sensor  402  (step  611 ), where the height sensor takes a measurement (step  612 ). The tray is conveyed such that it is stopped in a pre-determined position ready to be lifted (step  613 ). The lift engages the tray (step  614 ). The lift height is determined based on the height sensor measurement (step  615 ). The lift is then controlled to set the height of the lift to the determined lift height (step  616 ). The tray is then conveyed for printing, maintaining the lifted height during the printing process (step  617 ), and in particular as the print surface(s) of the articles of manufacture are printed by the print head(s)  70 . 
     Returning to  FIGS. 9A, 9B, 10A and 10B , when an engaged tray  200  is to be released from the engagement plate  410 , the lift  420  is instructed to lower sufficiently to disengage the positioning pins  412  from the sockets/holes of the base plate  210  of the tray  200 . The main conveyance system  180  may therefore engage the released tray  200  and transport it out of the printing system  170 . 
     Referring again to  FIG. 9A , the printer system  170  may also include a curing unit  176 , such as an ultra-violet (UV) curing system. The trays  200  pass into the UV curing unit  176  immediately upon passing under the printhead(s)  70 , and then out of the print system  170 . At the exit, the tray  200  is transferred back to the main conveyor  181  and routed by the conveyance system  180  to the unloading station  140 . 
     Preferably, the printing system  150  includes one or more tray identifier reader(s)  177  positioned and configured to read the tray identifier  230  on each tray  200  as it enters the printing system  150 . In an embodiment, the tray identifier  230  is an RFID tag and the tray identifier reader  177  is an RFID read head. The signal from the RFID reader  177  is sent to the system controller  105  or the production server  101 , or an alternative remote control system, which translates the signal into a corresponding tray identifier from which the print job(s) currently associated with the tray can be identified and used to derive information needed to process the articles of manufacture at each station. For example, in an embodiment, information which can be derived from the tray identifier  230  includes the type of articles of manufacture  99  present on the tray. The information about the type of article of manufacture  99  can be used to selectively turn on or off one or more of the following functions: application of the wetting agent in the pre-treatment station  160 , application of the cleaning solution in the pre-treatment station  160 , activation of the cleaning brush in the pre-treatment station  160 , activation of ionization in the printing system  170 , application of plasma treatment in the printing system  170 , printing or not printing by the print heads  70 , and curing or not curing by the curing unit  176 . In alternative embodiments, the printer system  150  is a multi-functional unit that is configured not only to print articles of manufacture  99 , but also to engrave, etch, embroider, label, stamping, affix, or otherwise embed or imprint content information on an article of manufacture  99  which is conveyed by a tray passing therethrough. Each tray passing into the system can therefore be identified using the tray identifier, and one or more of the printing, engraving, etching, embroidering, labeling, stamping, affixing or other functionally embedding functions can be enabled to print, engrave, etch, embroider, label, affix, or otherwise embed the content contained in the print job (or “job”, generally) onto the articles of manufacture  99 . 
     System Control 
     The printing system  150  includes system controller  105 . In an embodiment, the system controller comprises a computing environment  500 , illustrated in  FIG. 5 , for controlling and managing the operations of the printing system. The computing environment  500  includes a general-purpose computing device in the form of a computer  510 , which may comprise any electronic device with computing and/or processing capabilities. The components of computer  510  may include, but are not limited to, one or more processors or processing units  520 , a system memory  530 , and a system bus  521  that couples various system components including processing unit(s)  520  to system memory  530 . 
     System bus  521  represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, such architectures may include an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnects (PCI) bus also known as a Mezzanine bus. 
     Computer  510  typically includes a variety of electronically-accessible media. Such media may be any available media that is accessible by computer  510  or another electronic device, and it includes both volatile and non-volatile media, removable and non-removable media, and storage and transmission media. 
     System memory  530  includes electronically-accessible media in the form of volatile memory, such as random access memory (RAM)  532 , and/or non-volatile memory, such as read only memory (ROM)  531 . A basic input/output system (BIOS)  533 , containing the basic routines that help to transfer information between elements within computer  510 , such as during start-up, is stored in ROM  531 . RAM  532  typically contains data and/or program modules/instructions that are immediately accessible to and/or being presently operated on by processing unit(s)  510 . 
     Computer  510  may also include other removable/non-removable and/or volatile/non-volatile electronic storage media. By way of example,  FIG. 5  illustrates a hard disk drive  541  for reading from and writing to a (typically) non-removable, non-volatile magnetic media (not separately shown); a magnetic disk drive  551  for reading from and writing to a (typically) removable, non-volatile magnetic disk  552  (e.g., a “floppy disk”); and an optical disk drive  555  for reading from and/or writing to a (typically) removable, non-volatile optical disk  556  such as a CD-ROM, DVD-ROM, or other optical media. Hard disk drive  541 , magnetic disk drive  551 , and optical disk drive  555  are each connected to system bus  521  by one or more data media interfaces  540 ,  550 . Alternatively, hard disk drive  541 , magnetic disk drive  551 , and optical disk drive  555  may be connected to system bus  521  by one or more other separate or combined interfaces (not shown). 
     The disk drives and their associated electronically-accessible media provide non-volatile storage of electronically-executable instructions, such as data structures, program modules, and other data for computer  510 . Although exemplary computer  510  illustrates a hard disk  541 , a removable magnetic disk  552 , and a removable optical disk  556 , it is to be appreciated that other types of electronically-accessible media may store instructions that are accessible by an electronic device, such as magnetic cassettes or other magnetic storage devices, flash memory cards, CD-ROM, digital versatile disks (DVD) or other optical storage, random access memories (RAM), read only memories (ROM), electrically erasable programmable read-only memories (EEPROM), and so forth. In other words, any electronically-accessible media may be utilized to realize the storage media of the exemplary computing system and environment  500 . 
     Any number of program modules (or other units or sets of instructions) may be stored on hard disk  541 , magnetic disk  552 , optical disk  556 , ROM  531 , and/or RAM  532 , including by way of example, an operating system  544 , one or more application programs  545 , other program modules  546 , and program data  547 . By way of example only, operating system  544  may comprise file system component(s), application programs  545  may comprise program and/or applications, and program data  547  may comprise files and/or the content thereof. 
     A user may enter commands and information into computer  510  via input devices such as a keyboard  562  and a pointing device  561  (e.g., a “mouse”). Other input devices (not shown specifically) may include a microphone, joystick, satellite dish, serial port, scanner, and/or the like. These and other input devices are connected to processing unit(s)  520  via input/output interfaces  595  and  560  that are coupled to system bus  521 . However, they may instead be connected by other interface and bus structures, such as a parallel port, a universal serial bus (USB) port, an IEEE  1394  interface, an IEEE  802 . 11  interface, and so forth. 
     A monitor  591  or other type of display device may also be connected to system bus  521  via an interface, such as a video adapter  590 . In addition to monitor  591 , other output peripheral devices may include components such as speakers (not shown) and a printer  596 , which may be connected to computer  510  via network input/output interfaces  570 . 
     Networked Environment 
     Computer  510  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computing device  580 . By way of example, remote computing device  580  may be a personal computer, a portable computer (e.g., laptop computer, tablet computer, PDA, mobile station, etc.), a server, a router, a network computer, a peer device, other common network node, or other computer type as listed above, and so forth. In a particular example, the remote computing device  580  may be the production server  101  shown in  FIGS. 1A and 1B . Remote computing device  580  is illustrated as a computer that may include many or all of the elements and features described herein relative to computer  510 . Logical connections between computer  510  and remote computer  580  may be implemented as any one or more of a local area network (LAN)  571 , a general wide area network (WAN)  573 , a wireless network, etc. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, the Internet, fixed and mobile telephone networks, other wireless networks, and so forth. 
     When implemented in a LAN networking environment, computer  510  is connected to a local area network  571  via a network interface or adapter  570 . When implemented in a WAN networking environment, computer  510  typically includes a modem  572  or other means for establishing communications over wide area network  573 . Modem  572 , which may be internal or external to computer  510 , may be connected to system bus  521  via input/output interfaces  560  or any other appropriate mechanism(s). It is to be appreciated that the illustrated network connections are exemplary and that other means of establishing communication link(s) between computers  510  and  580  may be employed. 
     In a networked environment, such as that illustrated with computing environment  500 , program modules or other instructions that are depicted relative to computer  510 , or portions thereof, may be fully or partially stored in a remote memory storage device. By way of example, remote application programs  535  reside on a memory device  581  of remote computer  580 . Also, for purposes of illustration, application programs  528  and other executable instructions such as operating system  527  are illustrated herein as discrete blocks, but it is recognized that such programs, components, and other instructions reside at various times in different storage components of computing device  510  (and/or remote computing device  580 ) and are executed by data processor(s)  504  of computer  510  (and/or those of remote computing device  580 ). 
     Overview of Workflow Operations 
     As discussed previously, each production loop operations area  120   a,    120   b  includes at least one workstation which allows operators on each production loop to work independently yet share a single printing system  150 . Each operations area  120   a,    120   b  can be operated by one or more operators  2   a,    2   b,  depending on the workload. In an embodiment, when two operators  2   a,  b b  are present on a production loop  110   a,    110   b,  a first operator  2   a  handles the loading of trays  200  and the sort &amp; pack operations where as a second operator  2   b  handles the unloading and bagging operations. Of course, it will be appreciated that the workload could be partitioned in various other ways, including through the use of additional or fewer operators, and/or through the automation of one or more of the loading and unloading functions. 
     The various types of unprinted articles in their original packaging (e.g. carton boxes) are stored in racks  132  and are placed by the loading operator  2   a  into trays  200  which hold the corresponding type of article of manufacture. Different types of trays  200 , which are customized to carry a particular type of article of manufacture  99 , are stored in tray racks  135 . The green/yellow light Pick-to-Light system  190  visually guides the operator  2   a  to pick and place the correct articles  99  into the correct type of tray  200  and release it to the conveyor system  180  for further processing by the printing system  150 . 
     Identifiers  230 , such as RFID tags, embedded on or in the trays  200 , are used to tag each tray with process information (e.g. name of the image file to be printed, process parameters, workstation number etc.). This assures that the right content is printed onto each article of manufacture. The trays  200  are automatically routed to the infeed of the printing system  150  by the main conveyor system  180 . 
     In addition to the actual ink-jet printing process, the printing system  150  also preferably applies several pre-treatment and post-treatment processes to the articles of manufacture. The different processes, in preferred order of application, are as follows:
         1. Pre-Treatment: Selected application of one or more wetting agents followed by selected cleaning.   2. Ionized Air Wash: Naturalizes the surface electric charge on the promo items   3. Plasma Jet: Increases the surface energy of the articles of manufacture to allow better wetting by the ink   4. Ink-jet: Actual printing with four color (CMYK) digital ink-jetting print head with adjustable printhead-to-substrate distance.   5. UV-Pinning: An initial curing (for example using an LED light source) to fix the ink onto the print surface of the articles of manufacture immediately after the printing.   6. Final UV-Curing: Final curing by a strong mercury arc-lamp UV source.       

     Depending on the type of article of manufacture  99  on the tray  200 , as determined by the information associated with the identifier  230  on the tray  200 , each available process (pre-treatment, ionization, plasma jet, printing, UV pinning, UV-curing) can be automatically level adjusted (e.g., to set the intensity, amount of treatment of fluid, processing time, etc.) or altogether skipped, based on the information associated with the tray identifier  230 . 
     After the articles of manufacture  99  on the tray  200  have been fully processed (as determined from the information associated with the tray identifier  230 ), the tray  200  is routed back to the original operations area  120   a,    120   b  for unloading. A scanner is used by the unloading operator  2   b  to identify each article  99  removed from the tray  200 . The unloaded articles are then placed into the bagging machine and bagged into individual packages. The packages, or alternatively the individual articles themselves, are labeled for identification. 
     The bagged items are conveyed to the sort &amp; pack table via a secondary ground conveyor system. They are sorted, packed and forwarded to the platform outbound logistics process of the plant. 
       FIG. 12  is an operational flowchart illustrating an exemplary method  620  of operation of a printing system implemented in accordance with principles of the invention. As illustrated, material to be printed such as blank (as-yet unprinted) articles of manufacture are loaded into the materials staging rack (article of manufacture rack  131 ) for easy access by a loading operator (step  621 ). It will be appreciated that as used herein, the term “blank” article of manufacture refers merely to an article of manufacture which has at least one area intended to be printed on by the printing system and which has yet to be printed. An article of manufacture may, for example, have no printed material on it. Alternatively, an article of manufacture may include pre-printed material and may be submitted to the printing system for printing of additional material which is not yet printed thereon. In this case, the article of manufacture which still has one or more areas still intended to be printed would still, for purposes of this particular pass through the printing system, be considered a “blank” article of manufacture. 
     A print job is selected (step  622 ). In an embodiment, the print job is selected automatically by the production server  101  and communicated to the system controller  105 , which signals the Pick-To-Light system  190  to indicate what type of tray to load. In an alternative embodiment, the operator selects a print job from a queue of pending print jobs. The print job may be an individual print job associated with a single article of manufacture to be printed, or may be an aggregated gang of individual print jobs (an “aggregate” print job) for trays containing multiple articles of manufacture to be sent through the printer simultaneously. Upon selection of a print job, the operator selects one or more articles of manufacture of the type associated with the selected print job (step  623 ) and a tray configured to hold articles of manufacture of the type associated with the print job (step  624 ). The operator then loads the selected tray with the selected articles of manufacture (step  625 ). The individual print job and/or the aggregate print job is associated to an identifier on the tray (for example, the tray identifier  230  and/or individual slot identifiers in the tray) from which the production server and/or other devices can extract the information necessary to identify and associate each printed item with the order information (such as customer information, shipping address, etc.). The identifier indicating the individual print job(s) and/or aggregate print job is attached to or embedded in the loaded tray. The tray  200  is then released to the conveyance system  180  for transport to the printing system  170 . 
     The tray  200  is then conveyed by the conveyance system  180  to the entrance of the printing system  150 . Prior to or upon entry into the printing system  150 , a scanner reads the tray and/or slot identifier(s) from the tray  200  (step  628 ). The scanned identifier is matched to the print job to which the identifier is associated (step  629 ), from which a set of job processing instructions may be determined (step  630 ). The tray then passes through one or more of the print processing functions. For ease of explanation, the term “selectively applied” means a function referred to therewith is applied if the job processing instructions associated with the identifier of the tray indicate that the particular function should be applied, and is not applied if the job processing instructions indicate that the function should not be applied. Likewise, the term “selectively performed” means a function referred to therewith is performed if the job processing instructions associated with the identifier of the tray indicate that the particular function should be performed, and is not performed if the job processing instructions indicate that the function should not be performed. 
     In an exemplary embodiment, one or more wetting agent(s) are selectively applied (step  631 ), followed by a selectively performed cleaning process (step  632 ). An ionization wash may be selectively applied (step  633 ), as well as selective application of a plasma jet treatment (step  634 ). Further, the tray conveyance height may be selectively adjusted (step  635 ) prior to actual printing of the print job (step  636 ). Post-printing, the selective operations may include selectively performing one or more curing processes (step  637 ). It will be appreciated that all, fewer, or additional pre- and/or post-printing processes may be implemented and selectively applied using the selective indication in the job processing instructions associated with the tray identifier. 
     As described in connection with  FIGS. 8A-8D , the system may include a pre-treatment system  160 . For example, the pre-treatment system may include a wetting agent application and/or cleaning system. The pre-treatment system  160  may be integrated into the printing system or may be a separate system along the conveyance system and to and from or through which the conveyance system conveys a tray along the conveyance path. The tray enters the pre-treatment system, conveyed by the conveyance system, where the articles of manufacture are pre-treated. In an embodiment, a cleaning fluid is applied to the print surfaces of the articles of manufacture held on the tray which enters the pre-treatment system. The print surfaces may be brushed with the cleaning fluid and then the cleaning fluid may then be brushed, wiped, or otherwise removed from the print surface(s) of the articles of manufacture. In an embodiment, a wetting agent may be applied to the print surface(s) of the articles of manufacture to reduce ink reticulation and to encourage sticking of ink to the print surface(s) of the articles of manufacture. Whether and what type of cleaning fluid and/or wetting agent to apply will depend on the material and surface characteristics of the article of manufacture and is accordingly represented by way of the processing instructions associated with the identifier of the tray on which such articles are loaded. 
     As further described in connection with  FIGS. 9A and 9B , upon exit of the pre-treatment system  160 , if utilized, the tray  200  of pre-treated articles of manufacture is advanced to the printer system  170 . In an embodiment, an identifier reader such as an RFID reader scans/reads the tray identifier, which is matched up by the system controller  105  and/or production server  101  to an associated print job including a print file to be printed onto the print area(s) of the articles of manufacture on the tray and preferably an associated set of print processing instructions. In an embodiment, the print file includes individual print content to be printed on each of the respective articles of manufacture loaded on the tray. Potentially, the individual print content to be printed onto each of the individual articles of manufacture may be different for each article of manufacture. In an embodiment, the print file associated with the tray is a single aggregate print file comprising the individual print content for each of the individual articles of manufacture on the tray. The printing system treats the aggregate print file as a single print job and prints the file as if it is printing a single article of manufacture. 
     As further described in connection with  FIGS. 9A, 9B, 10A and 10B , in an embodiment, the printer system  170  includes a tray height adjustment system  400 , including a tray height or distance sensor  402  and a tray height adjustment mechanism  410 ,  420 ,  430 . In such an embodiment, upon or prior to entering the printer system  170 , the height or distance sensor  402  detects the height or distance to the print surface(s) of the articles of manufacture loaded on the tray. The distance adjustment mechanism translates the sensed height/distance into an adjustment amount and selectively raises or lowers the tray to achieve the adjustment amount. Alternatively, the distance adjustment mechanism raises or lowers the printhead(s) to achieve the adjustment amount. 
     To print the file associated with the tray, the printer (optionally adjusting the tray height or print head position to achieve optimal print-surface-to-print head distance) prints the print file content onto the print surface(s) of the articles of manufacture. In an embodiment, the printer system  170  includes a curing system such as a dryer or ultraviolet light. Referring again to  FIG. 12 , upon exit from the printing system, the tray is conveyed to the unloading area, where the individual articles of manufacture are unloaded from the tray (step  639 ), identified (step  641 ), and packaged (step  642 ). The tray itself is stored for use for processing another print job (step  640 ). 
     In an embodiment, at the unloading station the identifier (e.g., RFID tag) on the tray  200  is read by a scanner as the tray enters the unloading area. The print job currently associated with the scanned RFID is retrieved by the server and the individual orders are identified by position in the tray and sorted by the operator (step  641 ). In an embodiment, the individual orders are designated by position and communicated to an operator via a display screen. Additionally, shipping and/or order labels are automatically generated from order information associated with the individual order derived from the aggregate print job identifier. The operator can positionally and visually identify the printed article of manufacture associated with each individual order and can package and apply the shipping/packaging label to each individual order. 
       FIG. 13  is a more detailed block diagram of an online retail production system  700  implementing multiple aspects of the invention. In particular, the system  700  facilitates and implements the simultaneous mass production of individual orders of various different articles of manufacture printed with various individually-customized printed content. As shown in  FIG. 13 , an online retailer offering various different types of articles of manufacture individually customizable by individual customers with personalized printed content provisions one or more customer order server(s)  720  with web pages  724  which together implement a website  723 . Product content, such as templates  709 , layouts, designs, font schemes, color schemes, images, graphics, available for various different types of articles of manufacture are provisioned into a content database  791  or other computer storage by human or computer designers. 
     Any number of customers operating client computers  710  may access the website  723  hosted by the customer order server(s)  720  to view products (articles of manufacture) and product templates and to select, design, and/or customize various design components of a selected product prior to ordering. For example, multiple templates may be available for customizing or personalizing print content for printing on a product (article of manufacture) such as a drink holder (“koozie”)  99   a,  a tape measure  99   b,  a ruler  99   c,  a USB flash drive (“memory stick”)  99   d,  a magnetic clip  99   e,  a keychain tag  99   f,  a letter opener  99   g,  a foam cube (e.g., stress toy)  99   h,  a calculator  99   i,  or any other type of article of manufacture of a size suitable for printing in the conveyance printing system. 
     The various product templates may be selectable by the customer using client computer  710  for further customization such as adding customer-personalized information such as name, business name, address, phone number, website URL, taglines, etc. Furthermore, the template may include one or more image containers allowing a customer to upload one or more images into a selected design template  209 . The customer may edit a selected template and make design changes using a design tool  727 , and furthermore may preview the design using a preview tool  728 . Once a customer is satisfied with their selections/customizations, they can place an order  701  through an order and purchase tool  726  at the customer order server(s)  720 . Orders  701  are stored in an order database  792  and/or sent directly to a fulfillment center. 
     A production server  730  at a fulfillment center may retrieve orders  701  from the order database  792 , extract individual product documents  702  from the retrieved orders  792 , convert the individual product documents  702  into a set of related individual print files  703 , aggregate individual ordered products  701  into a set of gangs  704  containing individual product print files  703  associated with ordered articles of manufacture to be printed, and orders printing of a batch of articles of manufacture through the conveyance printing system  740  a “gang” at a time. Printed articles of manufacture exiting the printing process are sorted into their individual orders, packaged, and shipped or otherwise delivered to the respective individual customers. 
     System  700  is configured for mass production of customized printed products or items that may be of differing types, shapes, and construction. In this system, mass production includes the simultaneous printing of multiple articles of manufacture which can be ordered from multiple different customers. The content to be printed on the various ordered articles of manufacture can differ from order to order; thus, each article of manufacture to be printed can potentially be printed with unique content. 
     In the system shown in  FIG. 13 , a potentially enormous number (e.g., thousands or even hundreds of thousands or millions) of individual and commercial customers, wishing to place orders for one or more products of various different types, shapes, and construction materials, and which are to be printed with various graphical and customized designs printed or otherwise affixed thereon, access the system over a network  705 . In the illustrative embodiment, customers operating respective client computers  210  may access the system over the Internet or other network  705  via web browsers (or similar interactive communication software) running on personal computers, mobile devices (e.g., smartphones, tablets, or pad computers), or other electronic devices  710 . 
     In general, the orders  701  submitted by customers are short run manufacturing jobs, i.e., manufacturing jobs of products of a particular type and print design of less than 40,000 units, typically 1-5,000 units). Through the network  705 , each customer can access the website  723  comprising a plurality of related web pages  724  configured to allow a customer to select and customize a graphical design or template  709  to be printed, etched, engraved, stamped, affixed, or otherwise embodied on a product (e.g., koozies  99   a,  tape measures  99   b,  rulers  99   c,  memory sticks  99   d,  magnetic clips  99   e,  keychain tags  99   f,  letter openers  99   g,  stress toys  99   h,  calculators  99   i,  etc.). A product may be available in multiple different types and construction materials from which the customer may select. Design tool(s)  727  software may execute directly on the customer order server(s)  720 , or may be downloaded from the customer order server(s)  720  as part of web pages  724  displayed to the user to run in the user&#39;s browser on the customer&#39;s computer  710 . In an embodiment, the design tool(s)  727  enable the customer to perform simple design functions by completing a selected template using a Design Wizard, or more complex design functions using a Design Studio, locally in the browser. In an embodiment, the templates are embodied using an XML format or other appropriate format. 
     Once the customer has completed customization of the product template design, the customer places an order through the website  723  in conjuction with operation of an order and purchase tool  726 . At this point the customized product design template is referred to as an individual product document  701 . An individual product document  701  is a document description of an ordered article of manufacture, and in one embodiment is stored in an XML format. Placement of an order results in a collection of information associated with the order. The collection of information is referred to herein as an order  701 . The individual product document  701  is stored in an Orders database  792 . In an embodiment, the individual product document  701  stored in XML format, and the XML file is then converted by rendering software  732  at a production server  730  into a set of associated PostScript files print-ready such as an Adobe® .pdf or other such PostScript file. 
     The production server  730  may include scheduling software  731 . The scheduling software  731  operates to schedule the production of printed products based on parameters associated with the received orders  701 , such as shipping time, type of product, etc. 
     Rendering software  732  converts individual product documents  702  from the web format (e.g., &lt;XML&gt;or Document Object Model (DOM) descriptions) used in the web browser for displaying the web view of the design as seen by the customer during the design process to an associated print-ready (i.e., manufacturable) file  703 , such as a Postscript (e.g., .pdf) file ready to print by printing system of the conveyance printing system. 
     A Ganging system  733  fills predefined ganging templates containing placeholders for actual individual print-ready files  703  according to a schedule determined from the Scheduling module  731  in conjunction with the print job management function  731 . As an example,  FIG. 2C  depicts an example tray inlay  210   c  for holding a plurality of articles of manufacture  99   c.  As illustrated, the articles of manufacture  99   c  are aligned along both the x- and y-axes. 
     Given a tray  200  that aligned in the same position in the printer system  170  every time the tray  200  passes through the printer, and having an inlay  210   c  configured with fixed positions for holding articles of manufacture in aligned position, a gang corresponding to the layout of the articles to be engraved can be constructed. 
     In an embodiment, and with reference to  FIGS. 14A through 14D , individual article print files  703  from individual customer orders are arranged in a layout according to a predefined gang template  1000 . In an embodiment, the gang template  1000  is saved as a postscript file  704  such as a .pdf file defining a plurality of pre-positioned empty cells  1001 . A cell  1001  is a content container of pre-defined dimensions corresponding to a position and dimensions of a targeted print area of an article mounted on the tray  200  and positioned in the gang file layout in a unique pre-defined location in the gang template  1000 . Each empty cell  1001  may be filled with a single PostScript individual article print file  703 . 
     In the examples shown in  FIGS. 14A-14D , the gang template  1000  includes four cells  1001  of identical size arranged in a single row with the target print area aligned down the center of the available printable area. Each cell  1001  corresponds to a target print area on an individual article of manufacture. The cell layout shown in  FIGS. 14A-14D  is representative only and will vary across different types of articles, different target print areas on the articles, different numbers of articles accommodated by different trays, etc. 
     Referring back to  FIG. 13 , the cells  1001  in a gang template  1000  are filled according to an automated ganging algorithm, executed within the ganging system  733 . The ganging system  733  selects, from a gang template database  720 , a gang template  1000  appropriate to a particular article of manufacture and instantiates a gang print file  704  for that particular article of manufacture. The ganging system  733  selects items scheduled for production and begins filling corresponding cells of the instantiated gang file  704  with the corresponding individual article print files  703  until the gang is filled. If the ordered quantity of printed articles associated with an individual customer order is greater than one, then additional instances of the individual article print file  703  may be placed in additional cells of the associated gang template  1000  to cause the ordered quantity of the item to be printed. 
     The filled gang file  704  is sent to the conveyance printing system  740 , where a tray of the type associated with the particular gang file  704  is loaded with corresponding articles of manufacture. The loaded tray is conveyed to the printing system  150 , where the gang file is printed as a single print job onto the articles of manufacture loaded on the tray  200 . The tray with printed articles is then conveyed to an unloading station  140 , wherein the printed articles are removed from the tray and sorted into individual orders by a human or a computerized sorting system. The sorted orders may then be packaged for shipping by a packaging system. 
     It will be appreciated that while one pattern may be printed on the multiple articles in a gang, alternatively and potentially each gang cell can contain a different individual print job and therefore individual print jobs corresponding to different customers and/or different print orders can be simultaneously printed onto multiple different articles within the same print job that is sent to the conveyance printing system  740 . It will be further appreciated that while embodiments of the tray inlay shown herein depict tray inlays configured to hold multiple instances of a single type article of manufacture, alternative tray inlays may be configured to hold articles of manufacture of multiple different types. For example, a tray inlay could hold a one each of articles of manufacture types  99   a,    99   b,    99   c  and  99   d.  The corresponding gang file would then include a cell for containing an individual article print file  703  for each type of article of manufacture  99   a,    99   b,    99   c  and  99   d.    
     As will be appreciated from the above detailed description, the conveyance printing system offers multiple advantages to the printing industry. Features include, but are not limited to:
         A continuous-flow printing system—no need to take the printer offline to change out printing pallets;   Ability to print multiple different types of article of manufacture without taking the system offline to change the pallet configuration;   Automated detection of article of manufacture to print;   Automated detection of height of articles of manufacture and adjustment of height of tray to bring print nozzles within specified tolerance of print surface;   Universal tray frame with removable and switchable article of manufacture specific tray inlay designed for each specific type of article of manufacture—the height of each inlay is adjusted to place the print surface of the loaded article(s) of manufacture at a predetermined height which is standardized across different types of articles of manufacture;   Automated system indicating to operator which type of tray to load next;   ergonomic tray handling;   Ability to easily insert a high-priority print job into the print manufacturing flow without stopping the flow or taking the printing system offline.   Ability to selectively program which functions to turn on or off based on information associated with the tray/slot identifier(s)       

     Those of skill in the art will appreciate that many of the control functions utilized in the systems and methods described and illustrated herein may be implemented in software, firmware or hardware, or any suitable combination thereof. For example, many control features may be implemented in software for purposes of low cost and flexibility. Thus, those of skill in the art will appreciate that the method and apparatus of the invention may be implemented by one or more processing devices (such as, but not limited to a computer, microprocessor, programmable logic devices, etc.) by which instructions are executed, the instructions being stored for execution on a computer-readable medium and being executed by any suitable instruction processor. Alternative embodiments are contemplated, however, and are within the spirit and scope of the invention. 
     Although this preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.