Abstract:
An electrophotographic printing machine comprising at least one print engine, an input media path delivering a print media to the print engine, an output media path removing the print media from the print engine, and a media handling transport disposed in at least one of the media paths. The media handling transport includes first and second device halves. Each of the device halves includes first, second and third body members, with the first end portion of the second body member disposed adjacent the first end portion of the first body member, the first end portion of the third body member disposed adjacent the second end portion of the first body member, and the second end portion of the third body member disposed adjacent the second end portion of the second body member. An inner body member defines a first media transport passageway with the second body member define, a second media transport passageway with the third body member, and a third media transport passageway with the first body member. The second end portions of the second and third body members define an abutting end of the device half, with the abutting end of the first device half disposed adjacent the abutting end of the second device half in an installed transport.

Description:
BACKGROUND 
       [0001]    This disclosure relates generally to a printing system. More particularly, the present disclosure relates to printing systems having multiple print engines. 
         [0002]    Printing systems adapted for use in high speed printing may employ two print engines arranged in tandem to achieve the required print speed. Each print engine prints on one side of the sheet. In this way, duplex prints are formed rapidly and at a high productivity. Each print engine may be an electrophotographic print engine. These print engines are identical to one another and have a photoconductive member that is charged to a substantial uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of a document being printed. Exposure of the charged photoconductive member effectively dissipates the charge thereon in the irradiated areas to record an electrostatic latent image on the photoconductive member corresponding to the informational areas desired to be printed. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the electrostatic latent image is developed with dry developer material comprising carrier granules having toner particles adhering triboelectrically thereto. However, a liquid developer material may be used as well. The toner particles are attracted to the latent image, forming a visible powder image on the photoconductive surface. After the electrostatic latent image is developed with the toner particles, the toner powder image is transferred to a sheet. Thereafter, the toner powder image is heated to permanently fuse it to the sheet. 
         [0003]    After the toner powder image has been formed on one side of the sheet, the sheet is advanced to the next print engine to have information printed on the other side thereof. The sheet may be inverted or the print engine may be oriented so as to print on the opposed side of the sheet. In any event, both print engines are substantially identical to one another and produce a sheet having information on opposite sides thereof, i.e., a duplex sheet. This is duplex printing. While electrophotographic print engines may be utilized, one skilled in the art will appreciate that any other type of print engines may also be used. For example, ink jet print engines, or lithographic print engines may be used. Furthermore, these print engines may be mixed and matched. Thus, the printing system does not necessarily require only electrophotographic print engines or only ink jet print engines or only lithographic print engines, but rather may have an electrophotographic print engine and an ink jet print engine, or any such combination. 
         [0004]    Should either of the print engines become non-operative, the entire print system becomes non-functional. Therefore, print engine down time must be avoided in print shops conducting high volume duplex printing of mission critical customer jobs. One method practiced by print shops to avoid such down time has been to install two printing systems, with one of the printing systems in operation and the other printing system acting as a back-up. While effective, this practice is quite expensive. 
         [0005]    U.S. Pat. No. 5,568,246 discloses a printing system including two print engines arranged in tandem. In this printing system, one of the print engines can still be utilized if the other print engines fails, by using the normal single engine duplexing operation. While the disclosed apparatus and methodology provide a cost effective solution, the printing system is dated and does not meet all of the needs of more modern print shops. 
       SUMMARY 
       [0006]    There is provided an electrophotographic printing machine comprising at least one print engine, an input media path delivering a print media to the print engine, an output media path removing the print media from the print engine, and a media handling transport disposed in at least one of the media paths. The media handling transport comprises first and second device halves, each including first, second and third body members, each having first and second end portions. The first end portion of the second body member is disposed adjacent the first end portion of the first body member, the first end portion of the third body member is disposed adjacent the second end portion of the first body member and the second end portion of the third body member is disposed adjacent the second end portion of the second body member. An inner body member is disposed intermediate the first, second and third outer body members. The inner body member and the second body member define a first media transport passageway, the inner body member and the third body member defining a second media transport passageway, and the inner body member and the first body member defining a third media transport passageway. The second end portions of the second and third body members define an abutting end of the device half. In an installed configuration, the abutting end of the first device half is disposed adjacent the abutting end of the second device half. 
         [0007]    The first, second and third body members each have an inner surface extending from the first end portion to the second end portion, each of the inner surfaces defines a guide having a substantially smooth uniform surface. The inner surfaces of the second and third body members each have an arcuate shape to change a direction of travel of a sheet of media substantially ninety degrees. The inner surface of the first body member has a substantially planar shape to maintain the direction of travel of a sheet of media. 
         [0008]    The inner body member has a first guide surface extending from a lower end portion to a first upper end portion, a second guide surface extending from the lower end portion to a second upper end portion, and a third guide surface extending from the first upper end portion to the second upper end portion. The first, second and third guide surfaces are disposed opposite to the inner surfaces of the first, second and third body members, respectively and define the first, second and third media transport passageways therebetween. 
         [0009]    Each device half further includes a first feed mechanism associated with the first end portion of the first body member and the first end portion of the second body member and a second feed mechanism associated with the second end portion of the first body member and the first end portion of the third body member. 
         [0010]    Each device half further includes a first drive mechanism associated with the lower end portion of the inner body member and the inner surface of the second body member, a second drive mechanism associated with the lower end portion of the inner body member and the inner surface of the third body member and a third drive mechanism associated with the inner surface of the first body member and the first guide surface of the inner body member. 
         [0011]    Each device half further includes a first diverter extending from a first end portion pivotally mounted proximate to the inner body member lower end portion to a free end disposed adjacent the abutting end of the device half, a second diverter extending from a first end portion pivotally mounted proximate to the inner body member first upper end portion to a free end disposed proximate to the first feed mechanism, and a third diverter extending from a first end portion pivotally mounted proximate to the inner body member second upper end portion to a free end disposed proximate to the second feed mechanism. Where the free end portion of each of the diverters is selectively movable between a first diverter position or a second diverter position by a positioning device. 
         [0012]    There is also provided a kit to convert a conventional electrophotographic copying or printing system to an electrophotographic copying or printing system that operates in a tightly integrated parallel printer mode or a tightly integrated serial printer mode. The kit comprises a media handling transport adapted to replace at least one media handling device of the conventional electrophotographic copying or printing system. The media handling transports comprise an upper body member having an inner surface extending from a first end portion to a second end portion. A lower body member has an inner surface extending from a first end portion to a second end portion. A first side body member has an inner surface extending from a upper end portion to a lower end portion. The upper end portion of the first side body member is disposed adjacent the first end portion of the upper body member and the lower end portion of the first side body member is disposed adjacent the first end portion of the lower body member. A second side body member has an inner surface extending from a upper end portion to a lower end portion. The upper end portion of the second side body member is disposed adjacent the second end portion of the upper body member and the lower end portion of the second side body member is disposed adjacent the second end portion of the lower body member. A first inner body member has a first guide surface extending from a lower end portion to a first upper end portion, a second guide surface extends from the lower end portion to a second upper end portion, and a third guide surface extends from the first upper end portion to the second upper end portion. The first guide surface and the first side body member inner surface define a first media transport passageway segment. The second guide surface and the second side body member inner surface define a second media transport passageway segment. The third guide surface and the upper body member inner surface define a first media transport passageway. A second inner body member has a first guide surface extending from an upper end portion to a first lower end portion, a second guide surface extending from the upper end portion to a second lower end portion, and a third guide surface extending from the first lower end portion to the second lower end portion. The first guide surface and the first side body member inner surface define a third media transport passageway segment. The second guide surface and the second side body member inner surface define a fourth media transport passageway segment. The third guide surface and the lower body member inner surface define a second media transport passageway. A first diverter extends downwardly from a first end portion pivotally mounted proximate to the first inner body member lower end portion to a free end. A second diverter extends upwardly from a first end portion pivotally mounted proximate to the second inner body member upper end portion to a free end. The free end portions of the first and second diverters are independently selectively movable between a first diverter position or a second diverter position whereby a sheet of media may be directed from the first media transport passageway segment to the third media transport passageway segment, from the first media transport passageway segment to the fourth media transport passageway segment, from the third media transport passageway segment to the first media transport passageway segment, from the third media transport passageway segment to the second media transport passageway segment, from the second media transport passageway segment to the third media transport passageway segment, from the second media transport passageway segment to the fourth media transport passageway segment, from the fourth media transport passageway segment to the first media transport passageway segment, or from the fourth media transport passageway segment to the second media transport passageway segment. 
         [0013]    There is further provided a method of converting a conventional electrophotographic copying or printing system to an electrophotographic copying or printing system that operates in a tightly integrated parallel printer mode or a tightly integrated serial printer mode. The method comprises replacing each of the media handling devices of the conventional electrophotographic copying or printing system with a media handling transport. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The present disclosure may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which: 
           [0015]      FIG. 1  is a simplified schematic view of a conventional printing machine; 
           [0016]      FIG. 2  is an enlarged view of Area A of  FIG. 1 ; 
           [0017]      FIG. 3  is an enlarged view of Area B of  FIG. 1 ; 
           [0018]      FIG. 4  is a schematic view of a media transport device half according to the present disclosure; 
           [0019]      FIG. 5  is a schematic view of a media handling transport operating in a first configuration; 
           [0020]      FIG. 6  is a schematic view of a media handling transport operating in a second configuration; 
           [0021]      FIG. 7  is a schematic view of a media handling transport operating in a third configuration; 
           [0022]      FIG. 8  is a schematic view of a media handling transport operating in a fourth configuration; 
           [0023]      FIG. 9  is a schematic view of a media handling transport operating in a fifth configuration; 
           [0024]      FIG. 10  is a simplified schematic view of a printing machine having the media handling transport device of  FIG. 5 . 
           [0025]      FIG. 11  is an enlarged view of Area C of  FIG. 10 ; 
           [0026]      FIG. 12  is an enlarged view of Area D of  FIG. 10 ; and 
           [0027]      FIGS. 13   a,    13   b  and  13   c  are schematic views of a pair of the printing machines of  FIG. 10  arranged in tandem, showing the printing machines in three modes of operation. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    With reference to the drawings wherein like numerals represent like parts throughout the several figures, a tightly integrated serial hybrid printing system in accordance with the present disclosure is generally designated by the numeral  10 . 
         [0029]    In  FIGS. 1 ,  2  and  3 , there is shown, a conventional electrophotographic copying or printing system  10  for processing, printing and finishing print jobs. One example of the illustrated electrophotographic copying system  10  is the well known Xerox Corporation model iGen3™ duplicator. The exemplary copying system  10  includes three media handling devices that are operated by a system controller to direct sheet material on the proper paper path for any given operation of the system  10 . The first media handler (registration input and duplex inverter media handling transports) receives new sheet material from a simplex path, and partially processed sheet material from a duplex return paper path. The first media handler either directs the sheet material to the image path or to the bypass path. Sheet material traveling in the bypass path is transported directly through the second media handler (duplex upper and lower turn media handling transports) to the third media handler (output inverter), which then directs the sheet material out of the printing system through the bypass exit. Sheet material traveling in the image path has a first side processed by the image module. The second media handler then either directs the sheet material back to the first media handler, via the duplex return paper path, or to the third media handler, via a transport path. If the sheet material has been fully processed, the third media handler directs the sheet material out of the copying system  10  via an output path. If the second side of the sheet material must be processed, the third media handler directs the sheet material back to the first media handler via the bypass path, thereby inverting the sheet material. While such electrophotographic copying systems  10  are versatile and in wide use, their functionality is limited in that they cannot function in a tandem mode of operation. 
         [0030]    A media handling transport  110  in accordance with the present disclosure comprises two, substantially identical, device halves  112 ,  112 ′. As shown in  FIGS. 5-8 , the device halve  112 ,  112 ′ are mounted together with the abutting end  114  of a first device half  112  disposed adjacent the abutting end  114  of a second device half  112 ′. As shown in  FIG. 4 , each device half  112 ,  112 ′ includes three outer body members (first and second side body members  116 ,  118  and upper/lower body member  120 ), and an inner body member  122 . To facilitate discussion, the device half  112 ,  112 ′ will be discussed in the orientation shown in  FIG. 4 , although it should be understood that the media handling transport  110  may be installed in any orientation. 
         [0031]    The first and second side body members  116 ,  118  are substantially identical and are made of any suitable, durable material. Each side body member  116 ,  118  has an inner surface  124 ,  126 , extending from a lower or abutting end portion  128 ,  130  to an upper end portion  132 ,  134 , that forms a guide having a smooth uniform surface such that a leading edge of a sheet is not stubbed or caught by a portion of the inner surface  124 ,  126 . In the embodiment shown in  FIG. 4 , inner surfaces  124 ,  126  have an arcuate shape optimized to change the direction of travel of a sheet ninety degrees. The upper/lower body member  120  has an inner surface  136 , extending horizontally from a first end portion  138  associated with the upper end portion  132  of the first side body member  116  to a second end portion  140  associated with the upper end portion  134  of the second side body member  118 . Inner surface  136  also forms a guide having a smooth uniform surface such that a leading edge of a sheet is not stubbed or caught by a portion of the inner surface  136 . In the embodiment shown in  FIG. 4 , inner surface  136  has a substantially horizontal shape optimized to maintain the direction of travel of a sheet. The inner body member  122  has a first guide surface  142  extending from a lower end portion  144  to a first upper end portion  146 , a second guide surface  148  extending from the lower end portion  144  to a second upper end portion  150 , and a third guide surface  152  extending horizontally from the first upper end portion  146  to the second upper end portion  150 . The first, second and third guide surfaces  142 ,  148 ,  152  each have a smooth uniform surface such that a leading edge of a sheet is not stubbed or caught by a portion of the guide surface. The first, second and third guide surfaces  142 ,  148 ,  152  are disposed opposite to inner surface  124 , inner surface  126  and inner surface  136 , respectively, have shapes complementary thereto, and define first, second and third paper transport passageways  149 ,  151 ,  153  therebetween. 
         [0032]    Each device half  112 ,  112 ′ includes a first feed mechanism  154 , associated with the upper end portion  132  of the first side body member  116  and the first end portion  138  of the upper/lower body member  120 , and a second feed mechanism  156 , associated with the upper end portion  134  of the second side body member  118  and the second end portion  140  of the upper/lower body member  120 . The feed mechanisms  154 ,  156  may take the form of any feed mechanism capable of advancing the sheet. For example, the feed mechanism  154 ,  156  may be in the form of a drive roll  158  rotated by a motor  160  and a driven roll  162 . The sheet is drawn in the direction of travel at a nip  164  between the drive roll  158  and the driven roll  162 . The drive roll  158  and driven roll  162  may be rotatably mounted in the upper end portion  132 ,  134  of the side body member  116 ,  118  and the end portion  138 ,  140  of the upper/lower body member  120 , respectively (as shown in  FIG. 4 ). Alternatively, the drive roll  158  and driven roll  162  may be rotatably mounted in the end portion  138 ,  140  of the upper/lower body member  120  and the upper end portion  132 ,  134  of the side body member  116 ,  118 , respectively. 
         [0033]    Each device half  112 ,  112 ′ also includes a first drive mechanism  166 , associated with the lower end portion  144  of the inner body member  122  and inner surface  124 , a second drive mechanism  168 , associated with the lower end portion  144  of the inner body member  122  and inner surface  126 , and a third drive mechanism  170 , associated with inner surface  136  and guide surface  152 . The drive mechanisms  166 ,  168 .  170  may take the form of any drive mechanism capable of advancing the sheet. For example, the drive mechanism  166 ,  168 .  170  may be in the form of a drive roll  172  rotated by a motor  160  and a driven roll  174 . The sheet is drawn in the direction of travel at a nip between the drive roll  172  and the driven roll  174 . The drive roll  172  and driven roll  174  may be rotatably mounted in the side body member  116 ,  118  and the lower end portion  144  of the inner body member  122 , respectively (as shown in  FIG. 4 ). Alternatively, the drive roll  172  and driven roll  174  may be rotatably mounted in the lower end portion  144  of the inner body member  122  and the side body member  116 ,  118 , respectively. The distance D between either feed mechanism  154 ,  156  and a drive mechanism  166 ,  168 ,  170  is dictated by the minimum length of the media that will be utilized in the copying system  10 . Drive motors  160  connected to the drive mechanisms  166 ,  168 ,  170  and feed mechanisms  154 ,  156  are controlled to advance, retract, or hold a sheet of media as directed by the controller. The controller may also control the speed of the drive motors  160 . 
         [0034]    Each device half  112 ,  112 ′ further includes three diverters  176 ,  178 ,  180  for selectively directing the sheets as they pass through the media handling transport  110 . Each diverter  176 ,  178 ,  180  may have any suitable configuration capable of selectively directing the sheet. In the examples shown in  FIGS. 4-9 , the diverters  176 ,  178 ,  180  are in the form of pivotable levers that are positively and selectively positioned in either a first diverter position or a second diverter position by a series of solenoids, cams and/or other positioning devices. The first diverter  176  is positioned below the lower end portion  144  of the inner body member  122 , between the first and second side body members  116 ,  118 . The first diverter  176  extends from a first end portion  182 , pivotally mounted proximate to the lower end portion  144  of the inner body member  122 , to a free end  184  disposed adjacent the abutting end  114  of the device half  112 ,  112 ′. The second diverter  178  extends from a first end portion  186 , pivotally mounted proximate to the inner body member  122  first upper end portion  146 , to a free end  188  disposed proximate to the first feed mechanism  154 . The third diverter  180  extends from a first end portion  190 , pivotally mounted proximate to the inner body member  122  second upper end portion  150 , to a free end  192  disposed proximate to the second feed mechanism  156 . 
         [0035]    As described above, the media handling transport  110  is formed by mounting two device halves  112 ,  112 ′ together, with the abutting end  114  of a first device half  112  disposed adjacent the abutting end  114  of a second device half  112 ′ and the second device  112 ′ half being a “mirror image” of the first device half  112 . The lower end portions  128 ,  130  of the side body members  116 ,  118  are pivotally mounted to facilitate access to the passageways between the side body member  116 ,  118  and the inner body member  122  in the event of a paper jam. 
         [0036]    The direction of sheet transport through an electrophotographic copying system  10  is easily controlled by the positioning of the three diverters  176 ,  178 ,  180  of each device half  112 ,  112 ′ of the media handling transport  110 . Baffles  194  are positioned adjacent the first and second feed mechanisms  154 ,  156 , forming a chute at the entrance/exit of each device half  112 ,  112 ′. The baffles  194  are mounted in a manner that allows for modularity to facilitate multi-use within a printer racetrack. The entry or exit angle defined by the baffles depends on the amount of media curl allowed by specification. 
         [0037]      FIG. 5  illustrates the positioning of the diverters  178 ,  180  when the media handling transport  110  is operating in a first configuration. In this configuration, the second and third diverters  178 ,  180  of either the first device half  112  or the second device half  112 ′ are in the second diverter position. Positioning the diverters  178 ,  180  in this manner creates an straight-through flow path through the media handling transport  110 , where paper entering the first device half  112  passes through the media handling transport  110  on the upper flow path  196 , and paper entering the second device half  112  passes through the media handling transport  110  on the lower media flow path  198 . 
         [0038]      FIG. 6  illustrates the positioning of the diverters  176 ,  178 ,  180  when the media handling transport  110  is operating in a second configuration. In this configuration, the first diverter  176  of the first device half  112  is in the first diverter position (free end  184  positioned adjacent the second side body member inner surface  126 , solid line  FIG. 4 ) and the second diverter  178  of the first device half  112  is in the first diverter position (free end  188  positioned adjacent the upper/lower body member inner surface  136 , solid line  FIG. 4 ). In the mirror image second device half  112 ′, the first diverter  176  is in the second diverter position (free end  184  positioned adjacent the first side body member inner surface  124 , dotted line  FIG. 4 ) and the third diverter  180  in the first diverter position (free end  192  positioned adjacent the upper/lower body member inner surface  136 , solid line  FIG. 4 ). As shown in  FIG. 6 , positioning the diverters  176 ,  178 ,  180  in this manner creates an S-shaped flow path through the media handling transport  110  that shifts sheet flow between an upper media flow path  196  and a lower media flow path  198 . The positions of the third diverter  180  of the first device half  112  and the second diverter  178  of the second device half  112 ′ are irrelevant, since neither diverter are in the media flow path. 
         [0039]      FIG. 7  illustrates the positioning of the diverters when the media handling transport is operating in a third configuration. In this configuration, the third diverter  180  of the first device half  112  is in the second diverter position, the second diverter  178  of the second device half  112 ′ is in the first diverter position, the first diverter  176  of the first device half  112  is in the second diverter position, and the first diverter  176  of the second device half  112 ′ is in the first diverter position. Positioning the diverters  176 ,  178 ,  180  in this manner creates an S-shaped flow path through the media handling transport  110  that shifts sheet flow between an upper media flow path  196  and a lower media flow path  198 . 
         [0040]      FIG. 8  illustrates the positioning of the diverters when the media handling transport  110  is operating in a fourth configuration. In this configuration, the second diverters  178  of both the first and second device halves  112 ,  112 ′ are in the first diverter position, the first diverter  176  of the first device half  112  is in the first diverter position, and the first diverter  176  of the second device half  112 ′ is in the second diverter position. Positioning the diverters  176 ,  178  in this manner creates a C-shaped flow path through the media handling transport  110  that reverses the direction of the media flow path and inverts the media. 
         [0041]      FIG. 9  illustrates the positioning of the diverters when the media handling transport  110  is operating in a fifth configuration. In this configuration, the first diverters  176  of both the first and second device halves  112 ,  112 ′ are in the second diverter position and the third diverters  180  of both the first and second device halves  112 ,  112 ′ are in the first position. Positioning the diverters  176 ,  180  in this manner creates a C-shaped flow path through the media handling transport  110  that reverses the direction of the media flow path and inverts the media. 
         [0042]    With reference to  FIGS. 10 ,  11  and  12 , the iGen3™ copying system can be easily converted to operate in both a tightly integrated parallel printer (TIPP) and tightly integrated serial printer (TISP) mode by modifying the duplex return paper path as a bi-directional paper path. Converting the duplex return paper path to a bi-direction paper path requires replacing the first, second and third media handling devices with first, second and third media handling transports  110 . In addition, one nip horizontal transport must be added between the second and third media handling transports  110 ,  110 ′,  110 ″ and another nip horizontal transport replaces the sloping duplex transport of the first media handling device. 
         [0043]    As described above, each media handling transport  110  has five modes of operation. Accordingly, replacing the three handling devices utilized in the conventional iGen3™ copying system with three media handling transports  110 ,  110 ′,  110 ″ produces a copying system that has great flexibility of operation. This flexibility of operation is further increased when two copying systems are installed in tandem, as shown in  FIGS. 13   a - 13   c.    
         [0044]      FIG. 13   a  shows the two copying systems operating in a Duplex Tandem mode of operation. In this mode of operation, the first media handling transport  110  of the first copying system is set to either the first configuration ( FIG. 5 ), to receive sheet material from an upper tray of a sheet material supply device, or in the third configuration ( FIG. 7 ) to receive sheet material from a lower tray of the sheet material supply device. In either configuration, the sheet material is directed to the upper media flow path  196 . The second media handling transport  110 ′ of the first copying system is set to operate in the first configuration ( FIG. 5 ) to either direct sheet material to the third media handling device  110 ″ in the upper media flow path  196  or to the first media handling transport  110  in the lower media flow path  198 . The third media handling transport  110 ″ of the first copying system is set to operate in either the first configuration ( FIG. 5 ), directing the sheet material along the upper media flow path  196  to the first media handling transport  110  of the second copying system, or the fourth configuration ( FIG. 8 ), directing the sheet material back to the second media handling transport  110 ′ along the lower media flow path  198 . The first and second media handling transports  110 ,  110 ′ of the second copying system are each operated in the first configuration ( FIG. 5 ), directing sheet material along the upper media flow path  196  to the third media handling transport  110 ″. The third media handling transport  110 ″ of the second copying system is operated in either the first configuration ( FIG. 5 ) to direct the sheet material out of the second copying system along the upper media flow path  196 , or in the second configuration ( FIG. 6 ) to direct the sheet material out of the second copying system along the lower media flow path  198 . 
         [0045]      FIG. 13   b  shows the two copying systems operating in a Duplex Standalone mode of operation. In this mode of operation, the first media handling transport  110  of the first copying system is initially set to the first configuration ( FIG. 5 ), to receive sheet material from an upper tray of the sheet material supply device and direct the sheet material to the second media handling transport  110 ′ along the upper media flow path  196 . The second media handling transport  110 ′ of the first copying system is set to operate in the fourth configuration ( FIG. 8 ), directing the sheet material back to the first media handling transport  110 ′ along the lower media flow path  198 . The first media handling transport  110  is reset to the fifth configuration ( FIG. 9 ) directing the sheet material to the second media handling transport  110 ′ along the upper media flow path  196 . 
         [0046]      FIG. 13   c  shows the two copying systems operating in a Simplex Bypass mode of operation. In this mode of operation, the first media handling transport  110  of the first copying system is set to either the first configuration ( FIG. 5 ), to receive sheet material from a lower tray of the sheet material supply device, or in the second configuration ( FIG. 6 ) to receive sheet material from an upper tray of the sheet material supply device. In either configuration, the sheet material is directed to the lower media flow path  198 . The second media handling transport  110 ′ of the first copying system is set to operate in the first configuration ( FIG. 5 ) to direct sheet material along the lower media flow path  198  to the third media handling transport  110 ″. The third media handling transport  110 ″ of the first copying system is operated in the third configuration ( FIG. 7 ) to direct the sheet material from the lower media flow path  198  to the upper media flow path  196  and out of the first copying system. The first media handling transport  110  of the second copying system is set to the first configuration ( FIG. 5 ), to receive sheet material from the first copying system and direct the sheet material along the upper media flow path  196  to the second media handling transport  110 ′. The second media handling transport  110 ′ of the second copying system is set to operate in the first configuration ( FIG. 5 ) to direct sheet material along the upper media flow path  196  to the third media handling transport  110 ″. The third media handling transport  110 ″ of the second copying system is operated in either the first configuration ( FIG. 5 ) to direct the sheet material out of the second copying system along the upper media flow path  196 , or in the second configuration ( FIG. 6 ) to direct the sheet material out of the second copying system along the lower media flow path  198 . 
         [0047]    The media handling transports  110  are sized to fit within the free space left within the copying system after the media handling devices are removed. It should be understood that the operating software of the copying system controller must be modified to control the media handling transports  110 . 
         [0048]    It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.