Patent Publication Number: US-11027561-B2

Title: Ink jet card printer having a dual belt card transport

Description:
BACKGROUND 
     Card products include, for example, credit cards, identification cards, driver&#39;s licenses, passports, and other card products. Such card products generally include printed information, such as a photo, account numbers, identification numbers, and other personal information. Credentials can also include data that is encoded in a smartcard chip, a magnetic stripe, or a barcode, for example. 
     Card production systems include processing devices that process card substrates (hereinafter “cards”) to form the final card product. Such processes may include a printing process, a laminating or transfer process, a data reading process, a data writing process, and/or other process used to form the desired credential. An ink jet card printer is a form of card production system that utilizes an ink jet print head to print images to cards. 
     SUMMARY 
     Embodiments of the present disclosure are directed to an ink jet card printer, a method of printing images to cards using the ink jet card printer, and a card transport for use with an ink jet card printer. One embodiment of the ink jet card printer includes a card transport and a print unit. The card transport includes a first belt, a first motor configured to drive the first belt to feed a card along a processing axis, a second belt, and a second motor configured to drive the second belt to feed a card along the processing axis. The print unit includes an ink jet print head and a gantry. The ink jet print head is configured to perform a print operation simultaneously on a card supported in a print position on the first belt and on a card supported in a print position on the second belt. The gantry is configured to move the ink jet print head along a fast scan axis that is parallel to the processing axis and a slow scan axis that is perpendicular to the processing axis. 
     In one embodiment of a method of printing images to first and second cards using an ink jet printer having a card transport including first and second belts, and a print unit including an ink jet print head and a gantry, the first card is supported in a print position on the first belt and the second card is supported in a print position on the second belt. A first image is printed on the first card and a second image is printed on the second card using the ink jet print head including moving the ink jet print head in a fast scan direction across the first and second cards and moving the ink jet print head in a slow scan direction that is perpendicular to the fast scan direction using the gantry. The first card is discharged from the first belt by feeding the first card in a first direction along a processing axis that is parallel to the fast scan direction using the first belt. 
     One embodiment of the card transport includes first and second belts, each of which is configured to feed a card along a processing axis. The first belt is driven by a first motor, and the second belt is driven by a second motor. The first and second belts each include an input/output end and a passing end. The passing ends of the first and second belts are configured to simultaneously engage a card fed between the first and second belts. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are simplified side and top views of an ink jet card printer, in accordance with embodiments of the present disclosure. 
         FIG. 3  is an isometric view of an exemplary card transport and card feeders (lowered positions), in accordance with embodiments of the present disclosure. 
         FIG. 4  is a side view of an exemplary ink jet card printer with the card feeders in their lowered positions, in accordance with embodiments of the present disclosure. 
         FIG. 5  is a side view of the printer of  FIG. 4  with frame sidewalls removed, in accordance with embodiments of the present disclosure. 
         FIG. 6  is a side view of the printer of  FIG. 4  with the card feeders in their raised positions, in accordance with embodiments of the present disclosure. 
         FIG. 7  is a side view of the printer of  FIG. 6  with frame sidewalls removed, in accordance with embodiments of the present disclosure. 
         FIGS. 8 and 9  are front and top isometric views of a portion of an ink jet card printer at an interface between a card feeder and a belt, in accordance with embodiments of the present disclosure. 
         FIG. 10  is a top view of a portion of an ink jet card printer, in accordance with embodiments of the present disclosure. 
         FIGS. 11-16  are simplified top views of a card transport and card feeders during various stages of a printing operation, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Embodiments of the present disclosure are generally directed to a card feeder of an ink jet card printer that is configured to facilitate the feeding individual cards to a print position for printing by an ink jet print head that is moved through a print zone using a gantry during printing operations. The card feeder has a raised position, in which at least a portion of the card feeder extends into the print zone. As a result, the card feeder would obstruct printing operations if left in the raised position. This issue is avoided by moving the card feeder to a lowered position during printing operations, in which the card feeder is displaced from the print zone, using a lift mechanism. 
     These and other embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. Elements that are identified using the same or similar reference characters refer to the same or similar elements. The various embodiments of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. 
       FIGS. 1 and 2  are simplified side and top views of an ink jet card printer  100  in accordance with embodiments of the present disclosure. In some embodiments, the printer  100  includes a print unit  102 , and a card transport  104 . The card transport  104  is configured to feed individual cards  106  along a processing axis  108 . The print unit  102  includes an ink jet print head  110  and a gantry  112 . The print head  110  is configured to perform a printing operation on individual cards  106  supported by the card transport  104  in a print position  114  along the processing axis  108 . The gantry  112  is configured to move the print head  110  through a print zone  116  during printing operations. 
     In some embodiments, the printer  100  includes a controller  118 , which represents one or more distinct controllers of the printer  100 , each of which includes at least one processor that is configured to execute program instructions stored in a computer-readable media or memory of the printer  100 , which may also be represented by the controller  118 , or another location. Any suitable patent subject matter eligible computer readable media or memory may be utilized including, for example, hard disks, CD-ROMS, optical storage devices, flash memory, magnetic storage devices, or other suitable computer readable media or memory that do not include transitory waves or signals. The execution of the instructions by the controller  118  controls components of the printer  100  to perform functions and method steps described herein. 
     As discussed in greater detail below, the card printer  100  may include one or more card feeders  120 , such as card feeders  120 A and  120 B, that are each configured to deliver cards  106  to, and receive cards  106  from, the card transport  104 . The printer  100  may also include one or more conventional card flippers  122 , such as flippers  122 A and  122 B, that are configured to invert the cards  106 . A conventional card supply  124 , such as a card cartridge containing a stack of cards, may be provided to supply cards  106  for processing by the printer  100 , and processed cards may be discharged and collected by a suitable card collector (e.g., a hopper)  126 . 
     The ink jet print head  110  may be any suitable conventional ink jet print head that is configured to perform a direct printing operation to individual cards  106  supported in the print positions  114  along the processing axis  108 . The gantry  112  includes a conventional gantry for moving the print head  110  along a fast scan axis  130  that is substantially parallel to the processing axis  108 , and a slow scan axis  132  that is substantially perpendicular to the processing axis  108 , as shown in  FIG. 2 , during printing operations. As used herein, the term “fast scan axis” refers to the axis along which the print head  110  is moved by the gantry  112  during an active printing phase of the operation, during which ink is discharged from the print head  110  to form the image on the card  106 . The term “slow scan axis” refers to the axis along which the print head  110  is moved by the gantry  112  during an inactive printing phase (ink is not discharged from the print head) to position the print head  110  for the next active printing phase. 
     In some embodiments, the gantry  112  and the print head  110  may occupy the print zone  116  during printing operations, which is indicated by dashed boxes in  FIGS. 1 and 2 . The print zone  116  generally extends from the processing axis  108 , or immediately above the processing axis  108 , into the space above the card transport  104  and the card feeders  120 . The print zone  116  may also surround the card transport  104  and the card feeders  120 , as shown in  FIG. 2 . 
     In some embodiments, the card feeders  120  each include a lift mechanism  134  to move the card feeders  120  to a lowered position  136 , in which the card feeders  120  are displaced from the print zone  116 , such as below the print zone  116 , as indicated by card feeder  120 A in  FIG. 1 , and the card feeders  120 A and  120 B in  FIGS. 3-5 .  FIG. 3  is an isometric view of exemplary card transport  104  and card feeders  120  in their lowered positions  136 ,  FIG. 4  is a side view of an exemplary printer  100  with the card feeders  120  in their lowered positions  136 , and  FIG. 5  is a side view of the printer  100  of  FIG. 4  with frame side walls removed, in accordance with embodiments of the present disclosure. 
     The lift mechanisms  134  may also move the card feeders  120  to a raised position  138 , in which at least a portion of the card feeders  120  extend into the print zone  116 , and the card feeders  120  are positioned to feed cards  106  to, or receive cards  106  from, the card transport  104 , as indicated by the card feeder  120 B in  FIG. 1  and the card feeders  120 A and  120 B in  FIGS. 6 and 7 .  FIG. 6  is a side view of the exemplary printer  100  of  FIG. 4  with the card feeders  120  in their raised positions, and  FIG. 7  is a side view of the printer  100  of  FIG. 6  with frame side walls removed, in accordance with embodiments of the present disclosure. Thus, the card feeders  120  may be moved to their raised positions  138  by the lift mechanisms  134  to facilitate feeding cards  106  to, or receiving cards  106  from the card transport  104 . 
     Thus, the lift mechanisms  134  may be used to move the card feeders  120  from their raised positions  138 , in which at least a portion of the card feeders  120  would obstruct a printing operation, to their lowered positions  136 , in which the card feeders  120  do not obstruct the print zone  116 , to enable the print head  110  to be moved through the print zone  116  by the gantry  112  and perform a printing operation. 
     In some embodiments, the card transport  104  includes belts  140 , such as first and second belts  140 A and  140 B (i.e., belt feeders or conveyors), that are each supported by rollers  142  for movement along a belt path. In one example, the first and second belts  140 A and  140 B are each supported by four rollers  142 , which are supported by a belt frame  144 , such as side walls  146 A and  146 B of the belt frame  144  ( FIG. 3 ). The belts  140  include exposed portions  150  adjacent the processing axis  108 . The exposed portion  150  of each of the belts  140  is used to feed the cards  106  along the processing axis  108  and support the cards  106  in the print positions  114 . 
     Motors  154 A and  154 B are respectively configured to independently drive the first and second belts  140 A and  140 B along their belt paths. Thus, the exposed portion  150  of the first belt  140 A may independently feed a card  106  along the processing axis  108  in a direction toward the second belt  140 B or in a direction toward the card feeder  120 A using the motor  154 A, and the exposed portion  150  of the second belt  140 B may independently feed a card  106  along the processing axis  108  in the direction toward the first belt  140 A, or in the direction toward the card feeder  120 B using the motor  154 B. 
     The belts  140  of the card transport  104  may take on any suitable form. In some embodiments, the belts  140  are conventional vacuum belts that are coupled to a vacuum source  158  (i.e., a source of negative pressure), such as a regenerative vacuum blower. The vacuum source  158  may be shared by the belts  140 , as shown in  FIG. 1 , or separate vacuum sources  158 A and  158 B may respectively be used by the belts  140 A and  140 B, as shown in  FIG. 5 . Chambers  160  couple the negative pressure generated by the vacuum source  158  to the exposed portions  150  of the belts  140 . The negative pressure is communicated to a top side of the exposed portions  150  through apertures  162  in the belts, which are shown in  FIGS. 2 and 3 , and is used to secure cards  106  to the exposed portions  150  during card feeding and printing operations. Thus, when a card  106  engages the top surface of the exposed portion  150  of one of the belts  140 , the negative pressure generated by the vacuum source  158  or sources  158 A and  158 B adheres the card  106  to the belt  140 . When the belts  140  are driven by the corresponding motor  154 , the adhered card  106  is driven along the processing axis  108 . 
     During a printing operation, with the card feeders  120  in their lowered positions  136 , each of the belts  140  may feed a card  106  along the processing axis  108  to the corresponding print position  114 , in which the exposed top surfaces  166  of the cards  106  are at the border of the print zone  116 , as shown in  FIGS. 1, 2, 4 and 5 . The print head  110  may perform a print operation on the top surfaces  166  of the cards  106  supported in the print positions  114 . Thus, the print head  110  may print an image to the exposed surface  166  of the card  106  supported in the print position  114  on the belt  140 A, print an image to the surface  166  of the card  106  supported in the print position  114  on the belt  140 B, and/or simultaneously print images to the surfaces  166  of both cards  106  supported in the print positions  114  on the belts  140 A and  140 B during a single printing operation. 
     For example, referring to  FIG. 2 , with the card feeders  120  in their lowered positions  136 , and the cards  106  held in the print positions  114  against the exposed portions  150  of the belts  140 A and  140 B due to the negative pressure generated by the vacuum source  158  or sources  158 A and  158 B ( FIGS. 1, 2, 4 and 5 ), the gantry  112  may move the print head  110  along the fast scan axis  130  (processing axis  108 ) over the cards  106 , while the print head  110  prints image lines to the surfaces  166 , as indicted by arrow  170 . After the print head  110  is moved past the end of the card  106  adjacent the card feeder  120 B, the gantry  112  shifts the print head  110  along the slow scan axis  132 , as indicated by arrow  172 . The gantry  112  then moves the print head  110  back along the fast scan axis  130  (arrow  174 ), during which the print head  110  prints image lines to the surfaces  166  of the cards  106 . The gantry  112  again shifts the position of the print head  110  along the slow scan axis  132  (arrow  176 ), and the print head  110  prints image lines as the gantry  112  moves the print head  110  along the fast scan axis  130  (arrow  178 ). These steps of printing image lines while moving the print head  110  along the fast scan axis  130  and shifting the position of the print head  110  along the slow scan axis  132 , are repeated until the images have been printed to the surfaces  166  of the cards  106 . Accordingly, a single print operation may simultaneously print images to two cards  106  supported on the belts  140 . 
     To print a full edge-to-edge image on a card  106 , the print head  110  may be configured to print an image that is slightly larger than the surface  166  of the card  106 . As a result, some ink will overspray the edges of the card  106 . 
     In some embodiments, the exposed surface  150  of each belt  140  has a smaller surface area than the card  106 . That is, the width and length of the exposed belt surfaces  150  are selected such that they are less than the corresponding width and length of the cards  106 , as generally shown in  FIG. 2  with the cards  106  shown in phantom lines. Thus, when a card  106  is in the print position  114 , the entirety of the exposed belt surface  150  is covered by the card  106 , and a perimeter portion  180  of the card  160  extends beyond the edges of the exposed belt surface  150 . This allows the print head  110  to print images that extend to the edges of the surfaces  166  of cards  106  while protecting the exposed belt surface  150  from ink contamination. 
     In some embodiments, the printer  100  includes an ink overspray collector  182  that surrounds a perimeter of the exposed belt surface  150  and extends beyond the edges of the cards  106  when in their print positions  114 , as shown in  FIG. 2 . Thus, the collector  182  is positioned to receive ink that is sprayed over the lengthwise and widthwise edges of the cards  106  during a printing operation. In some embodiments, the ink overspray collector  182  is a disposable component that may be periodically removed and replaced by an operator of the printer  100 . The collector  182  may be formed of plastic, paper, cardboard, or another suitable material. In some embodiments, the collector  182  is a single piece of material having an opening  184 A for the exposed belt surface  150  of the belt  140 A, and an opening  184 B for the exposed belt surface  150  of the belt  140 B. 
     As mentioned above, the card feeders  120  are each configured to deliver cards  106  to, and receive cards  106  from the card transport  104  when in their raised positions  138  ( FIGS. 6 and 7 ). The card feeders  120  may also receive cards  106  for processing from the card supply  124 , such as using card feeder  120 A, and discharge processed cards  106  to the collector  126 , such as using the card feeder  120 B, as indicated in  FIG. 1 . 
     In some embodiments, the card feeders  120  each include at least one pinch roller pair  190 , such as pinch roller pairs  190 A and  190 B, as shown in  FIGS. 1, 5 and 7 . In some embodiments, at least a portion of one or both of the pinch roller pairs  200  extends into the print zone  116  when the card feeder  120  is in the raised position  138 , as shown in  FIG. 7 . The pinch roller pairs  190 A and  190 B are respectively positioned adjacent ports  192  and  194  of the card feeder  120 , with the port  192  being positioned adjacent an input/output end  196  of the corresponding belt  140 , as shown in  FIG. 3 . Each pinch roller pair  190  may include an idler roller  197  and a motorized feed roller  198  ( FIGS. 5 and 7 ) that are supported by a card feeder frame  200 , such as between side walls  201 A and  201 B of the frame  200 , as shown in  FIG. 3 . While the idler roller  197  is illustrated as being the top roller in the provided examples, it is understood that the positions of the rollers  197  and  198  may be reversed. A cover  202  may be positioned between the pinch roller pairs  190 A and  190 B to cover a portion of the path through which cards  106  are fed through the card feeder  120 , as shown in  FIG. 3 . 
     The card feeders  120 A and  120 B respectively include motors  204 A and  204 B ( FIG. 1 ) for driving the motorized rollers  198  to feed a card  106  supported between one or both of the pinch roller pairs  190 A and  190 B along a card feed axis  208 . The separate motors  204  of the feeders  120  allow the controller  118  to independently control the card feeders  120 . As a result, the card feeder  120 A may be used to deliver a card  106  to the belt  140 A while the card feeder  120 B delivers a card  106  to the collector  126 , for example. 
     The card feed axis  208  of each feeder  120  is substantially parallel to a vertical plane extending through the processing axis  108 . Thus, as shown in the top view of  FIG. 2 , the card feed axes  208  of the feeders  120  are oriented substantially parallel (e.g., ±5 degrees) to the processing axis  108  within a horizontal plane. 
     In some embodiments, the lift mechanisms  134  pivot the frame  200  of the card feeders  120  about a pivot axis  210  ( FIG. 3 ) during movement of the card feeders  120  between their raised and lowered positions  138  and  136 . As a result, the orientation of the card feed axis  208  relative to the processing axis  108  in a vertical plane changes with movement of the card feeders  120  between their raised and lowered positions  138  and  136 . When the card feeder  120  is in its lowered position  136 , the card feed axis  208  is at an oblique angle (e.g., 20-50 degrees) to the processing axis  108  in the vertical plane, as shown in  FIG. 5 . When the card feeder  120  is in its raised position, the card feed axis  208  is substantially parallel to the processing axis  108  in the vertical plane, as shown in  FIG. 7 , allowing the card feeder  120  to deliver a card  106  to the adjacent belt  140 , or receive a card  106  from the adjacent belt  140  using one or more of the pinch roller pairs  190 . 
     In some embodiments, the pivot axis  210  is defined by a pivotable connection  212  between the card feeder frame  200  and the belt frame  144 , as indicated in  FIG. 3 . In one embodiment, the pivotable connection or hinge  212  is formed between the side walls  201 A and  201 B of the card feeder frame  200  and the corresponding side walls  146 A and  146 B of the belt frame  144 . 
     In one exemplary embodiment, each lift mechanism  134  includes a cam  216 , a cam follower  218  and a motor  220 , as shown in  FIGS. 5 and 7 . The separate motors  220  allow the controller  118  to independently control each lift mechanism  134 . In one example, each cam  216  is supported by the belt frame  144  for rotation about an axis  222  ( FIG. 3 ), and each cam follower  218  is supported by the card feeder frame  200  and pivots with the card feeder frame  200  about the pivot axis  210 . Alternatively, the positions of the cam  216  and the cam follower  218  may be reversed where the cam  216  is supported by the belt frame  144  and the cam follower  218  is supported by the card feeder frame  200 . In some embodiments, the cam follower  218  is biased to engage the cam  216  using a suitable biasing mechanism, such as a spring. 
     During an exemplary lift operation, in which the card feeder  120  is moved from the lowered position  136  ( FIG. 5 ) to the raised position  138  ( FIG. 7 ), the controller  118  activates the motor  220  of the lift mechanism  134  to drive rotation of the cam  216  about the axis  222  in the direction indicated by arrow  224  in  FIG. 3 . As the cam  216  rotates, it slides and presses against a cam surface  226  ( FIG. 5 ) of the cam follower  218 . This drives the card feeder frame  120  to pivot about the pivot axis  210  until the card feeder  120  reaches the raised position  138  shown in  FIG. 7 . The operation is reversed to move the card feeder  120  back to its lowered position  136 . That is, the controller activates the motor  220  of the lift mechanism  134  to drive rotation of the cam  216  about the axis  222  in the direction opposite arrow  224  ( FIG. 3 ). During this rotation of the cam  216 , the cam surface  226  of the cam follower  218  slides along the cam  216  and the card feeder frame  200  pivots about the pivot axis  210  until the card feeder  120  reaches the lowered position  136  shown in  FIG. 5 . 
     Alternative lift mechanisms  134  may also be employed. For example, different lift mechanisms may be used to pivot the card feeders  120  between their raised and lowered positions  138  and  136 , such as a screw drive, or another suitable lift mechanism. Additionally, the lift mechanisms  134  may be configured to move the card feeders  120  linearly between the raised and lowered positions  138  and  136 . 
     In some embodiments, a lateral stabilizer  230  is used in connection with each of the card feeders  120  to ensure substantial coaxial alignment in the horizontal plane between the card feed axis  208  and the processing axis  108  of the adjacent belt  140 , as shown in  FIG. 2 , when the card feeders  120  are in their raised positions  138 . One example of a suitable lateral stabilizer  230  is shown in  FIGS. 8 and 9 , which are front and top isometric views of a portion of the printer  100  at the interface between the card feeder  120 A and the belt  140 A with the ink collector  182  removed. In some embodiments, the lateral stabilizer  230  is positioned between the pinch roller pair  190 A at the port  192  and the input/output end  196  of the adjacent belt  140 A, as shown in  FIG. 8 . 
     In one embodiment, the lateral stabilizer  230  includes a first stabilizing member  232  connected to the card feeder frame  200 , and a second stabilizing member  234  connected to the belt frame  144 . Thus, the first stabilizing member  232  moves with movement of the card feeder frame  200  about the pivot axis  210  relative to the second stabilizing member  234 . The first stabilizing member  232  engages with the second stabilizing member  234  in a cooperating manner when the card feeder  120  is moved from the lowered position  136  to the raised position  138  to provide the desired lateral alignment of the card feed axis  208  and the processing axis  108 . In some embodiments, the first and second stabilizing members  232  and  234  are displaced from each other when the card feeder  120  is in the lowered position  136 . 
     In one exemplary embodiment, the first stabilizing member  232  is in the form of a rib member and the second stabilizing member is in the form of a groove  234 , as shown in  FIGS. 8 and 9 . Alternatively, the positions of the rib member and groove may be reversed. The groove  234  may be formed in a bar  236  extending between the side walls  146 A and  146 B of the belt frame  144 . As the card feeder  120  is moved from the lowered position  136  to the raised position  138 , the rib member  232  is received within the groove  234 , as shown in  FIG. 9 , to align the card feed axis  208  with the processing axis  108  and maintain the alignment during card feeding operations between the card feeder  120 A and the belt  140 A. 
     Ideally, each card feeder  120  supports a received card  106  such that a central axis of the card  106  is aligned with the card feed axis  208 . This ensures that the card  106  is fed to the adjacent belt  140  in alignment with the processing axis  108 , which allows for accurate positioning of the card  106  in the print position  114  on the belt  140  and accurate printing of an image to the card surface  166 . 
     In some embodiments, each card feeder  120  includes a card alignment mechanism  240 , an example of which is illustrated in the top view of a portion of the printer  100  provided in  FIG. 10  with the cover  202  removed. The card alignment mechanism  240  is configured to prevent misalignment between a card  106  supported by the one or more pinch roller pairs  190  of the card feeder  120  and the card feed axis  208 . One embodiment of the card alignment mechanism  240  includes a reference wall  242 , a pusher wall  244  and a biasing mechanism  246 . The reference wall  242  is aligned parallel to the card feed axis  208  and has a fixed position relative to the card feeder frame  200 . The pusher wall  244  is moveable relative to the card feeder frame  200  and the reference wall  242 . The biasing mechanism  246  is configured to bias the pusher wall  244  toward the reference wall  242 . Embodiments of the biasing mechanism  246  include a spring or another conventional biasing mechanism. 
     As a card  106  is received by the card feeder  120  with the central axis of the card  106  being offset from the card feed axis  208  or non-parallel to the card feed axis  208 , the pusher wall  244  pushes the card  106  toward the reference wall  242  due to the bias produced by the biasing mechanism  246 . This causes an edge of the card  106  to engage the reference wall  242 . As the card  106  continues to be fed into the card feeder  120  by the pinch roller pairs  190 , the edge of the card  106  engaging the reference wall  242  aligns with the reference wall  242  and aligns the central axis of the card  106  with the card feed axis  208 . 
     The printer  100  may include one or more sensors  250  to facilitate various card feeding operations, such as receiving a card  106  in the card feeders  120  and positioning a card  106  in the print position  114  on the belts  140 . In one embodiment, the printer  100  includes a card sensor  250  for detecting the presence or absence of a card at each side of the card transport  104 , as indicated in  FIG. 1 . In some embodiments, the card sensors  250  are positioned between the pinch roller pair  190 A and the adjacent belt  140 . In some embodiments, the card sensors  250  are supported by the card feeder frame  200 , as shown in  FIGS. 3 and 8 . The card sensors may take on any suitable form, such as an optical card sensor having an emitter  252  and a receiver  254 , as shown in  FIG. 8 . 
     During reception of a card  106  by a card feeder  120  in its lowered position  136 , the sensor  250  may be used to detect the leading edge of the card  106  being fed toward the card transport belt  140 , which may indicate that the card  106  is fully received in the card feeder  120 . The card feeder  120  may then be moved from the lowered position  136  to the raised position  138 . After the card feeder  120  is moved to the raised position  138 , the corresponding card sensor  250  may be used to detect the trailing edge of the card  106  as the card is fed to the adjacent belt  140 . The controller  118  may use this detection of the trailing edge of the card  106  to control the belt  140  to position the card  106  in the desired print position  114 . 
     The card sensors  250  may also be used by the controller  118  to control the reception of cards  106  fed from the belts  140  by the card feeders  120 . For example, as a card  106  is fed from the belt  140  toward the card feeder  120 , the card sensor  250  may detect the leading edge of the card  106 . This detection may be used by the controller  118  to control the pinch roller pairs  190  to receive the card  106  in the card feeder  120 . The card  106  may then be fed into the card feeder  120  using the pinch roller pairs  190  until the sensor  250  detects the trailing edge of the card  106  indicating that the card  106  has been fully received within the card feeder  120  and that the card feeder  120  is ready to be moved to its lowered position  136 . 
     As mentioned above, the printer may optionally include one or more card flippers  122  that may be used to invert cards  106  to facilitate printing operations on both sides of the cards  106 . Each card flipper  122  may be configured to receive a card  106  from the adjacent card feeder  120 , the card supply (flipper  122 A) or the card collector (flipper  122 B), rotate the card  106  about a flipping axis  260  to invert the card  106 , and pass the inverted card  106  back to the adjacent card feeder  120 , which can deliver the inverted card  106  to the card transport  104  and the print unit  102  for a printing operation. The card flippers  122  may each be conventional card flippers. One suitable card flipper  122  which may be used by the printer is described in U.S. Pat. No. 7,878,505, which issued to HID Global Corporation and is incorporated herein by reference in its entirety. 
     In some embodiments, each flipper  122  includes a pinch roller pair  262  that is configured to hold the card  106  during rotation about the flipping axis  260 . One or more motors  264  ( FIGS. 1 and 5 ) are used to drive rotation of a gear  266 , that supports the pinch roller pair  262  and a card  106  supported by the pinch roller pair, about the flipping axis  260 . In some embodiments, the card feed axis  268  of each flipper  122  is configured to rotate into alignment with the card feed axis  208  of the adjacent card feeder  120  when it is in the lowered position  136 . The motor  264  may also drive the pinch roller pair  262  to feed a card  106  supported by the pinch roller pair  262  to the pinch roller pair  190 B at the port  194  of the adjacent card feeder  120 , such as shown in  FIG. 5 . The adjacent card feeder  120  may then move to the raised position  138  and feed the card  106  to the adjacent belt  140 , as shown in  FIG. 7 . 
     Some embodiments of the present disclosure are directed to methods of printing an image to one or more cards  106  using the ink jet card printer  100 . In one embodiment of the method, a card  106 , which may have been received from the supply  124  and fed to the card feeder  120 A by the card flipper  122 A, is supported by the pinch roller pairs  190  of the card feeder  120 A while in its lowered position  136 , as shown in  FIG. 5 . The card feeder  120 A is moved to its raised position  138  using the corresponding lift mechanism  134 , and the card  106  is discharged from the card feeder  120 A to the belt  140 A using the pinch roller pair  190 A. The card feeder  120 A is then moved to the lowered position  136  ( FIGS. 4 and 5 ) and out of the print zone  116  using the lift mechanism  134 , and the card  106  is fed along the processing axis  108  by the belt  140 A to the print position  114  ( FIG. 2 ). An image is then printed to the surface  166  of the card  106  using the print head  110 , which involves moving the print head  110  with the gantry  112  through the print zone  116 , as indicated in  FIGS. 1 and 2 . 
     Some embodiments of the method involve performing a print operation using the ink jet card printer  100  to print images on two cards  106  simultaneously. One example of such a method will be described with reference to  FIGS. 11-16 , which are simplified top views of the card transport  104  and the card feeders  120 A and  120 B during various stages of the method. Initially, a pair of cards  106  may be fed from the supply  124  to the card transport  104  with the card feeders  120  in their lowered positions  136 . This may involve feeding a first card  106  from the supply  124  through the card flipper  122  to the card feeder  120 A, as shown in  FIGS. 1 and 5 . The card feeder  120 A may then be moved to its raised position  138  using the lift mechanism  134 , and the first card  106 A is fed to the belt  140 A by the pinch roller pair  190 A, as shown in  FIG. 11 . The card feeder  120 A may then return to its lowered position  136 , and a second card  106  may be fed from the supply  124  through the flipper  122 A to the card feeder  120 A in the same manner as the first card. During the feeding of the second card  106 A to the card feeder  120 A, the first card  106 A may be fed by the belt  140 A to the belt  140 B, during which the card  106 A is simultaneously supported by both belts  140 A and  140 B, as shown in  FIG. 12 . The card  106 A may then be moved by the belt  140 B to the print position  114 , as shown in  FIG. 13 . The second card  106 B is fed to the belt  140 A using the pinch roller pair  190 A of the card feeder  120 A, as indicated in  FIG. 13 , and the second card  106 B is moved along the processing axis  108  by the belt  140 A to its print position  114 , as shown in  FIG. 14 . The card feeder  120 A is then moved to its lowered position  136 . 
     With the cards  106 A and  106 B supported in their print positions  114  on the belts  140 B and  140 A, and the card feeders  120 A and  120 B in their lowered positions  136  ( FIG. 5 ), a printing operation is simultaneously performed on the first and second cards  106 A and  106 B using the print unit  102 , as discussed above with reference to  FIG. 2 . This printing operation involves moving the ink jet print head  110  in the fast scan direction  130  across the cards  106  and moving the ink jet print head  110  in a slow scan direction  132  that is perpendicular to the fast scan direction  134  through the print zone  116  using the gantry  112 . The cards  106  are imaged by the ink jet print head (i.e., active printing phase) while the print head  110  is moved in the fast scan direction  130  by the gantry  112 . 
     After the images have been printed to the cards  106 A and  106 B, the card feeders  120 A and  120 B are returned to their raised positions  138  by the lift mechanisms  134 , and the cards  106 A and  106 B are delivered to the adjacent card feeders  120 A and  120 B using the belts  140 A and  140 B, as indicated in  FIG. 14 . After receiving the cards  106 A and  106 B, the card feeders  120 A and  120 B are moved to their lowered positions  136  by the lift mechanisms  134 , and the cards  106 A and  106 B are fed to the corresponding flippers  122 A and  122 B, such as generally shown in  FIG. 5 . The flippers  122 A and  122 B invert the cards  106 A and  106 B and feed the inverted cards back to the card feeders  120 A and  120 B, which are then returned to their raised positions  138 . The cards  106 A and  106 B are then fed back to the adjacent belts  140 A and  140 B by the card feeders  120 A and  120 B, as indicated in  FIG. 15 . The belts  140 A and  140 B then move the cards  106 B and  106 A to the print positions  114  ( FIG. 13 ) and the card feeders  120 A and  120 B are again moved to their lowered positions  136 . The print head  110  then prints images to the non-imaged surfaces  166  of the cards  106 A and  106 B as discussed above with reference to  FIG. 2 . 
     With images printed to both sides of the cards  106 A and  106 B, the cards may be discharged to the collector  126  using the card feeder  120 B. The card feeder  120 B is first moved to the raised position  138 , and the belt  140 B feeds the card  106 A to the card feeder  120 B. The card feeder  120 B is then moved to its lowered position  136 , and the card  106 A is fed to the collector  126  through the flipper  122 B ( FIG. 5 ). The card  106 B is fed from the belt  140 A to the belt  140 B and the card feeder  120 B is returned to the raised position  138 . The card feeder  120 B then receives the card  106 B from the belt  140 B, and is moved to its lowered position  136  by the corresponding lift mechanism  134 . The card  106 B can then be discharged from the card feeder  120 B to the collector  126  through the flipper  122 B. 
     Although the embodiments of the present disclosure have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure. It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the present disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. As used herein the term “approximately,” “about” or “substantially” generally refers to ±5% of the referenced value and denotes equality with a tolerance of at most 5%, unless stated otherwise. The terms “substantially parallel” or “substantially perpendicular” refer to a tolerance of ±5 degrees, unless otherwise specified.