Patent Publication Number: US-7717632-B2

Title: Card printer printhead mounting

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application is a continuation of U.S. patent application Ser. No. 11/823,034, filed Jun. 26, 2007 now abandoned and U.S. patent application Ser. No. 10/936,885, filed Sep. 9, 2004 now abandoned; and the present application claims the benefit of U.S. provisional patent application Ser. No. 60/502,535, filed Sep. 12, 2003. The content of each of the above-referenced applications is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   The present invention generally relates to a card printer, such as an identification card printer. Some aspects of the present invention relate to reverse-image identification card printers. 
   Reverse-image identification card printers generally utilize an intermediate transfer film or ribbon on which an image is printed by a printhead. The printhead is typically a thermal printhead that operates to heat different colored dye panels of a thermal print ribbon to transfer the colored dye from the print ribbon to a panel of transfer film and form the image thereon. The printed image on the transfer film is then registered with a card or other substrate and the image is transferred to a surface of the card from the transfer film. 
   Such reverse-image identification card printers are complicated devices and improvements are in continuous demand. For example, there is a continuous demand for improved reliability and improved print quality. Additionally, there are demands for improving the process by which the print and transfer ribbons are loaded. Finally, there are demands to make the printers more compact. 
   SUMMARY OF THE INVENTION 
   Embodiments of the present invention relate to a card printer comprising a moveable printhead mounting. In accordance with one embodiment, the card printer comprises a print platen, a first support, a printhead, and a biasing component. The first support is moveable, relative to the platen, between print and withdrawn positions. The printhead is moveably mounted to the first support for movement between a forward position and a floating position relative to the first support. The biasing component is configured to apply a biasing force to bias the printhead toward the forward position. 
   Another embodiment of the invention is directed to a card printer comprising a platen, a first support, a printhead, a cam member and a motor. The first support is moveable, relative to the platen, between print and withdrawn positions. The printhead is mounted to the first support and applies a pressure to the platen when the first support is in the print position and is displaced from the platen when the first support is in the withdrawn position. The cam member engages the first support and moves the first support between the print and withdrawn positions in response to rotation of the cam member. The motor is configured to drive the rotation of the cam member. 
   Other features and benefits that characterize embodiments of the present invention will be apparent upon reading the following detailed description and review of the associated drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1 and 2  are perspective views of an exemplary identification card printer having a swing arm assembly respectively in closed and opened positions, in accordance with embodiments of the invention. 
       FIG. 3  is a schematic diagram of an identification card printer in accordance with embodiments of the invention. 
       FIGS. 4 and 5  are side views of the printer shown in  FIGS. 1 and 2  with a side wall of the printer frame removed, portions in cross-section, and the swing arm assembly respectively in the closed and opened positions. 
       FIGS. 6 and 7  are simplified top views of a transfer film sensor adjacent a transfer film, in accordance with embodiments of the invention. 
       FIGS. 8 and 9  are schematic illustrations of a printhead mounting in accordance with embodiments of the invention. 
       FIGS. 10 and 11  are magnified views of a printing section of the printer shown in  FIG. 4  illustrating different positions for the printhead. 
       FIG. 12  is a flowchart illustrating a method of calibrating a ribbon sensor in accordance with embodiments of the invention. 
       FIG. 13  is a partial exploded perspective view of a card output portion of the printer shown in  FIG. 4 , in accordance with embodiments of the invention. 
       FIG. 14  is a simplified partial front assembled view of a swing arm brake, in accordance with embodiments of the invention. 
       FIGS. 15 and 16  respectively are exploded and assembled perspective views of a card guide, in accordance with embodiments of the invention. 
       FIG. 17  is a cross-sectional view of a card guide shown in  FIG. 16  taken along line  17 - 17  with the addition of top guide rollers and a card. 
       FIG. 18  is an exploded perspective view of a card bender in accordance with embodiments of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   ID Card Printer Overview 
     FIGS. 1 and 2  are perspective views of an exemplary identification card printer  100  having a swing arm assembly  102  respectively in closed and opened positions, in accordance with embodiments of the invention. In accordance with one embodiment of the invention, the printer  100  is a reverse-image printer that operates in a similar manner as that discussed in U.S. Pat. No. 6,261,012, which issued Jul. 17, 2002 and is assigned to Fargo Electronics, Inc. of Eden Prairie, Minn. However, as will be clear to those skilled in the art, while some aspects of the present invention relate specifically to reverse-image printers, others can be useful in both reverse-image printers and printers that print images directly to cards using thermal printheads, inkjet printheads, and other types of conventional printing mechanisms. 
     FIG. 3  is a schematic diagram illustrating various components of the printer  100 , and  FIGS. 4 and 5  are side views of the printer shown in  FIGS. 1 and 2  with a side wall  101  of the printer frame removed, portions in cross-section, and the swing arm assembly  102  respectively in the closed and opened positions. Several components of the printer  100 , such as communication and electrical connections between the various components, drive belts, card substrate stacks, and other components of printer  100  are not shown in order to simplify the illustrations. Similarly labeled elements in the figures correspond to the same or a similar element. 
   In general, printer  100  includes a printing section  104  and an image transfer section  106 . The printing section  104  includes a supply of thermal print ribbon  108 , a print ribbon sensor  110 , a printhead  112 , a supply of transfer film or ribbon  114 , and at least one transfer film sensor  116 . A controller  119  ( FIG. 3 ) generally controls the components of printer  100  to perform various operations including printing, image transfer, ribbon tension calibration, sensor calibration, and other operations. 
   The print ribbon supply  108  is stored on supply and take-up spools  118  and  120 , respectfully, and the ribbon  108  extends between the printhead  112  and a print platen  122 . The ribbon sensor  110  can be a slotted optical sensor that includes an emitter and receiver pair  123 , or other suitable sensor. The ribbon sensor  110  is configured to detect different color frames or panels along the length of the print ribbon  108 . The frames or panels repeat in a sequence or group consisting of a yellow, magenta, and cyan panels. In addition, a black resin frame or panel can be provided in the sequence of the color panels, if desired. As will be discussed below in greater detail, embodiments of the invention relate to automatically setting the tension in the print ribbon  108  and/or transfer ribbon  114 . 
   The transfer ribbon  114  is stored on supply and take-up spools  124  and  126 , respectively, and extends between the print ribbon  108  and the print platen  122 . The transfer ribbon  114  includes substantially clear or transparent panels  130  that are separated by a relatively opaque transition mark  131 , as shown in the simplified top views of  FIGS. 6 and 7 . The transfer film sensor  116  (e.g., a slotted optical sensor) detects the transition marks  131  for the printer controller  119 , which uses the sensor  116  to control the feeding of the transfer ribbon  114  in both a upstream direction and a downstream or feeding direction (feeding direction indicated by arrow  132 ) through the control of a bi-directional motor  127  ( FIG. 3 ) in order to align the desired panel  130  with the printhead  112 . The sensor  116  preferably includes an emitter  133  and a receiver  134  that are positioned on opposite sides of the transfer film  114  and are configured to detect the transitions  131  separating the panels  130 . As will be discussed below in greater detail, embodiments of the present invention relate to the calibration of the sensor  116  and the positioning of the sensor and its components relative to other components of the printer  100 . 
   The printer controller  119  generally controls the operation of printer  100  including the feeding of the print ribbon  108  through control of a motor  135  ( FIG. 3 ). The alignment of the ribbon  108  and the printhead  112  is performed based on a signal from the ribbon sensor  110 . Likewise, the controller  119  controls the feeding of the transfer ribbon  114  relative to the printhead  112  and other components of the printer  100  using the sensor  116 . 
   Controller  119 , is preferably formed on a single printed circuit board, and includes the control electronics for controlling the printing section  104  and the image transfer section  106  of printer  100 . This is an improvement over prior art printer designs that utilize separate printer controllers and image transfer controllers formed on separate circuit boards. Such separation of the controllers leads to card processing problems due to miscommunications therebetween. Furthermore, the dual controller design requires additional components, which increases costs and the likelihood of a component failure. 
   The printhead  112  is preferably a thermal printhead, which operates with the print ribbon  108  to print an image to a panel  130  of the transfer ribbon  114  using heated print elements  136 . Alternatively, printhead  112  can also be an ink jet printhead that uses ink to print an image to the panel  130  of the transfer ribbon  114  rather than the print ribbon  108 . 
   In accordance with one embodiment of the invention, printhead  112  is configured to print upward onto a bottom surface  138  of individual transfer panels  130 . The printhead  112  is preferably aligned, as indicated by dashed line  140  ( FIG. 3 ), such that it is at an obtuse angle  142  relative to horizontal line  144 , or to a card path  146  that is substantially horizontal from a card input  148  to a card output  150 . Additional embodiments of the invention will be discussed below relating to the mounting of the printhead  112  in printer  100  and the maintaining of a substantially uniform pressure between the print elements  136  and the platen  122  during print operations. 
   The image transfer section  106  generally includes a heated transfer roller  180  and a transfer platen  182 . The heated transfer roller  180  is preferably a 60 watt unit, which can be heated to the desired temperature much quicker than the lower power units used by printers of the prior art. The transfer ribbon  114  is fed between the transfer roller  180  and the platen  182 . In accordance with one embodiment of the invention, the heated transfer roller  180  is positioned above the transfer platen  182 . Either the transfer roller  180  or the transfer platen  182  can be moved relative to the other with a suitable lifting mechanism such as with a motorized lift  183 , shown schematically in  FIG. 3 . One suitable motorized lift is described in U.S. patent application Ser. No. 10/418,730, filed Apr. 18, 2003, which is assigned to Fargo Electronics, Inc. of Eden Prairie, Minn., and is incorporated herein by reference in its entirety. 
   During a printing operation, the controller  119  controls the position of the panels of the print ribbon  108  and the panels  130  of the transfer ribbon  114  based upon signals from the print ribbon sensor  110  and the transfer ribbon sensor  116 . The print elements  136  of the printhead  112  heat the print ribbon  108  to cause dye to transfer to the transfer ribbon panel  130  in accordance with known methods. For a color image, multiple passes over the same transfer ribbon panel  130  are made by printhead  112 , each with a different color panel of the thermal print ribbon  108 . Once the desired image has been printed to the transfer ribbon panel  130 , the transfer ribbon panel  130  is moved to the image transfer section  106  ( FIG. 3 ). 
   A card feeding mechanism  184  comprising feeding and guide rollers  185  that can be formed in pinch roller pairs, preferably delivers individual cards  186  through the printer  100 . In general, the card feeding mechanism  184  feeds the individual cards  186  through the card input  148  and between the heated transfer roller  180  and the transfer platen  182 , as illustrated in  FIG. 3 . In accordance with one embodiment of the invention, the card feeding mechanism  184  initially feeds the card  186  through a card cleaner  187 , which cleans at least a print surface  188  of the card  186 , to which an image is to be transferred, prior to delivery of the card to the heated transfer roller  180 . 
   The transfer ribbon panel  130  containing the image to be transferred to the surface  188  of the card  186  is positioned between the surface  188  and the heated transfer roller  180 . The image on the panel  130  adheres to the surface  188  through the application of heat and pressure by the transfer roller  180  under the support of the transfer platen  182 . A suitable peel-off mechanism (not shown) can be positioned downstream of the heated transfer roller  180  and used to assist in the peeling of transfer ribbon  114  from the surface  188  while the image remains on the surface  188  to complete the printing of the image to the card  186 . The printed card  186  can then be fed by the card feeding mechanism  184  through the output  150  for collection in a hopper or for feeding to a laminating module or other card processing component for additional processing. 
   Printhead Mounting 
   One embodiment of the invention includes a moveable printhead mounting  190 , the general embodiments of which are shown in the schematic illustrations of  FIGS. 8 and 9  and more specific embodiments are shown, which provide magnified views of the printing section  104  of the printer shown in FIG.  4 . The mounting  190  facilitates loading and unloading of the print and transfer ribbons  108  and  114  and more accurate printing of images onto the transfer ribbon panels  130 . 
   The mounting  190  for the printhead  112  includes a first support  192 , such as a bracket, to which the printhead  112  is moveably mounted. The first support is moveable, as indicated by arrow  193  ( FIGS. 8 and 9 ) between a print position  194 , shown in  FIGS. 8 and 10 , and a withdrawn position  196 , shown in  FIGS. 9 and 11 . Print operations can occur when the first support  192  is in the print position  194 , in which a substantially uniform pressure is applied between the printhead  112  and the print platen  122 . When in the print position  194 , the print or resistive heating elements  136  of the printhead  112  squeeze the print ribbon  108  and the transfer ribbon  114  against the platen  122 . Removal and installation of the print and transfer ribbons  108  and  114  can occur when the printhead  112  is in the withdrawn position  196 , in which the first support  192  and the printhead  112  are displaced from the platen  122 . 
   In accordance with one embodiment of the invention, the movement of the first support  192  between the print and withdrawn positions  194  and  196  is provided by a head lift  198 , which is preferably driven by a motor  200  ( FIGS. 8 and 9 ) under control of controller  119 . The head lift  198  can include a rotatable cam member  202  that engages a cam follower  204  and drives the first support  192  toward the print position  194  through the controlled rotation of the cam member  202 . The first support is preferably guided between the print and withdrawn positions  194  and  196  by tab members extending through slots in the side walls  101  of the printer frame, or other suitable manner. 
   The print position  194  for the first support  192  is preferably defined by a first support stop  206 , shown generally in  FIGS. 8 and 9 , that engages the first support  192  to thereby limit the minimum spacing between the first support  192  and the print platen  122 . In accordance with one embodiment of the invention, the first support stop  206  includes an axle  208  of the platen  122  and the first support  192  includes an axle receiver  210  that engages the axle  208  when in the print position  194 , to thereby limit the minimum spacing between the first support  192  and the print platen  122 . The axle receiver  210  preferably includes a notch  212  ( FIG. 11 ) configured to receive the axle  208 . In accordance with one embodiment of the invention, the first support  192  includes a pair of axle receivers  210  that engage the axle  208  of the print platen  122  adjacent each of the side walls  101  of the printer frame. Those skilled in the art understand that many different types of first support stops  206  can be used to provide the desired limitation to the minimal spacing between the first support  192  and the print platen  122 . 
   The printhead  112  is preferably moveably mounted to the first support  192  to allow it to move relative to the first support  192  between a forward position  214  ( FIGS. 9 and 11 ) in which the printhead  112  is biased when the first support  192  is in the withdrawn position  196 , and a floating position  216  ( FIGS. 8 and 10 ) to which the printhead  112  moves when the first support  192  is in the print position  194  and the printhead  112  engages the platen  122 . In accordance with one embodiment of the invention, printhead  112  is mounted to a second support  218 , which in turn is moveably mounted to the first support for movement between the forward and withdrawn positions  214  and  216 . 
   One embodiment of the second support  218  includes a cross member  220  (e.g., a rod) that extends through slots  222  formed in side walls  223  of the first support  192  and preferably through the side walls  101  of the printer frame for additional support. The cross member  220  can slide within the slots  222  between the forward and withdrawn positions  214  and  216 . The forward position  214  can be defined by a stop member  224  that limits the movement of the printhead  112  and second support  218  toward the platen  122 . In accordance with one embodiment of the invention, the stop member  224  is formed by the end  226  of the slots  222  that is located toward the print platen  122  that limit the movement of the second support  218  toward the platen  122  relative to the first support  192 , as shown in  FIG. 9 . 
   A biasing mechanism  230  operates to apply a biasing force to the printhead  112  to thereby direct the printhead  112  toward the forward position  214 . In accordance with one embodiment of the invention, the biasing mechanism  230  includes at least one, but preferably two spring members  232  each positioned at an end of the printhead  112  or the second support  218 , such as leaf springs ( FIGS. 10 and 11 ), elastic bands, or other suitable biasing mechanisms. When the first support  192  is in the withdrawn position  196 , the biasing mechanism  230  directs the printhead  112  and/or the second support  218  to the forward position  214  as limited by the stop member  224 , as shown in  FIG. 9 . As the first support  192  is moved into the print position  194 , shown in  FIGS. 8 and 10 , pressure is applied to the printhead  112  by the print platen  122 , which overcomes the biasing force produced by the biasing component  230  and causes the printhead and/or the second support  218  to move into the floating position  216 . When in the floating position  216 , the biasing mechanism  230  applies a substantially uniform pressure to the print and transfer ribbons  108  and  114  against the platen  122  by the print elements  136  of the printhead  112 . The uniform pressure improves print image quality and color-to-color registration. 
   Ribbon Sensor Calibration 
   Referring again to  FIGS. 6 and 7 , which are simplified top views of the transfer film sensor  116  adjacent the transfer film  114 , in accordance with embodiments of the invention. As mentioned above, the transfer film sensor  116  preferably includes at least one emitter  133  and receiver  134  pair ( FIG. 3 ) which operate to detect transitions  131  that are between the individual panels  130  of transfer film  114  for use by controller  119  to control the feeding of the transfer film  114  relative to the printhead  112  and the heated transfer roller  180 . The transition  131  is generally detected by the sensor  116  when the transition  131  blocks the receiver  134  from detecting at least a threshold amount of a light signal that is transmitted by the emitter  133  as the transition  131  passes between the emitter  133  and the receiver  134 . 
   It is desirable to set the intensity of the light signal transmitted by the emitter  133  to a level that provides accurate detection of the transitions  131  of the transfer ribbon  114 . If the light signal has an intensity that is set too high, the light signal can bleed around, and possibly pass through, the transition  131  thereby preventing the detection of the transition. On the other hand, if the intensity of the light signal is set too low, the receiver  134  could fail to detect the light signal even when a panel  130  of the transfer film  114  is positioned between the emitter  133  and the receiver  134 . Therefore, proper calibration of the transfer film sensor  116  is essential for accurate detection of the transition  131 . 
   In accordance with one embodiment of the invention, the transfer ribbon sensor  116  is calibrated for transition detection either at the factory or during an initial start-up routine for printer  100 . The calibration routine can be performed either manually or automatically by the controller  119  of printer  100 , driver software, or a card manufacturing application running on an associated computer, for example. One embodiment of the calibration routine is illustrated in the flowchart of  FIG. 12 . Initially, at step  242 , the transition  131  of the transfer ribbon  114  is positioned beyond transfer ribbon sensor  116  such one of the non-printed panels  130  of the ribbon  114  is positioned between the emitter  133  and the receiver  134  to allow the emitter  133  to transmit the light signal through the panel  130 . At step  244 , the intensity of the light signal emitted by the emitter  133  of the sensor  116  is raised to a threshold level, at which the receiver  134  of the sensor  116  begins to detect the light signal. The intensity of the light signal transmitted by the emitter  133  is then set to an operating level that is at least equal to the threshold level, at step  246 . Preferably, the operating level is set slightly higher than the threshold level. Such calibration of the transfer ribbon sensor  116  ensures that the transitions  131  of the transfer ribbon  114  will be detectable by the sensor  116 . 
   Ribbon Sensors 
   Accurate positioning of individual transfer ribbon panels  130  relative to printhead  112  and the heated transfer roller  180  generally requires that the transfer ribbon sensor  116  be positioned at least the length of one panel  130  away from the element it is to be aligned with. The transfer ribbon sensors of the prior art have been positioned upstream of printhead  112  relative to the feeding direction  132  ( FIGS. 3 ,  6  and  7 ) of the transfer ribbon  114 . As a result, the supply spool  124  of transfer ribbon  114  must extend more than the length of one panel  130  away from the printhead  112  to accommodate such a sensor. As a result, it becomes necessary to form the printer large enough to accommodate the position of the sensor. 
   In accordance with one embodiment of the invention, the transfer ribbon sensor  116  includes first and second sensors  250  and  252  that are positioned downstream of the printhead  112  and upstream of the transfer roller  180 , as shown in  FIGS. 3 ,  6  and  7 . The first sensor  250  is positioned downstream of the second sensor  252 . The first and second sensors  250  and  252  are separated by a length that is less than a length of a transfer ribbon panel  130 . Each of the first and second sensors  250  and  252  are preferably optical sensors that each include an emitter  133  and a receiver  134  that are positioned on opposite sides of the transfer ribbon  114  and are configured to detect the transitions  131  between individual panels  130  of the transfer ribbon  114  for the controller  119 , as discussed above. The first and second sensors  250  and  252  are preferably calibrated as explained above to detect the transition  131 . 
   The first ribbon sensor  250  is preferably a print sensor that is used during printing operations to detect the position of a leading transition  256  downstream panel  258  relative to the printhead  112  and the feeding direction  132 , as illustrated in  FIG. 6 . In accordance with one embodiment of the invention, the first sensor  250  is positioned such that the detection of the leading transition  256  of the downstream panel  258  indicated by an output signal  259  from the receiver  184  indicates that the position of a trailing transition  260  of the downstream panel  258  or the leading transition  260  of the upstream panel  262  is aligned with printhead  112 . Accordingly, queuing the downstream panel  258  relative to the first sensor  250  queues the upstream panel  262  to the printhead  112 . As a result, the printhead  112  is prepared to print the desired image to either the upstream panel  262  or the downstream panel  258 . Following the printing of the desired image onto the selected transfer panel  130 , preferably the upstream panel  262 , the printed transfer panel is fed forward to the image transfer section  106 . 
   Second sensor  252  is preferably used to queue the printed panel  130  with the heated transfer roller  180  of the image transfer section  106  of the printer  100 . For this example, the panel  262  will be the printed panel. In general, the printed transfer panel  262  is fed forward until the second sensor  252  detects the trailing transition  264  of the printed transfer panel  262  as indicated by an output signal  266 , as shown in  FIG. 7 . Preferably, the second sensor  252  detects the trailing edge of the trailing transition  264  to avoid interference by the image printed on the panel  262 . The second sensor  252  is preferably the length of one panel  130  away from the heated transfer roller  180 . Accordingly, the printed panel  262  is positioned for image transfer to a properly positioned card  186  when the second sensor  252  detects the trailing transition  264  of the printed panel  262 , as shown in  FIG. 7 . 
   Ribbon Tension Calibration 
   During printing and image transfer operations, printer controller  119  maintains accurate control of the feeding and positioning of the print and transfer ribbons  108  and  114  relative to the printhead  112 , or the transfer ribbon  114  relative to the heated transfer roller  180 , using sensors  110  and  116  and encoder wheels  270 , such as those shown schematically in  FIG. 3 . The encoder wheels  270  have, for example, a plurality of angularly spaced apertures  272 , that are used to detect rotation of the encoder wheel  270  using optical sensors  274  in accordance with conventional methods. The encoder wheels  270  are preferably configured such that their rotation directly corresponds to a rotation of the corresponding supply spools  118  and  124 . As a result, the measure of the rotation of the encoder wheels  270  can be used to measure the rotation of the corresponding supply spools  118  and  124  and, hence, the amount of ribbon that is being fed or retrieved. For example, a count can be made of the passage of the apertures  272  of the encoder wheel  270 , or the light blocking portions between the apertures  272 , using the sensor  274 , to maintain an account of the feeding of the ribbon in accordance with known methods. 
   Installation of the print and image transfer ribbons  108  and  114  requires that they be fed through and around several components of the printer  100 , such as the sensors  110  and  116 , the printhead  112 , the platen  122 , and other components. It is generally necessary to create slack in the ribbons to perform the installation. The slack in the ribbons  108  and  114  must be removed between their supply and take-up spools to complete their proper installation. Prior art methods require the user to manually roll the supply and/or take-up spools of the ribbon supplies to remove the slack. Unfortunately, problems can arise due to the setting of too much, or too little, tension in the ribbon which can adversely affect the performance of the printer. 
   One embodiment of the present invention provides automated tensioning of the print ribbon  108  and/or the image transfer ribbon  114 . In general, following the installation of the ribbons  108  and  114  with the printhead  112  preferably in the withdrawn position  196 , the printer controller  119  drives the corresponding take-up spool, such as take-up spool  120  for the print ribbon  108 , or the take-up spool  126  for the transfer ribbon  114 , until the encoder wheel  270  of the corresponding supply spool  118  or  124  registers rotation of the supply spool using the corresponding sensor  274 . Once rotation of the supply spool is detected, the tension of the ribbon is properly set. 
   Swing Arm Assembly 
   Printer  100  includes a swing arm assembly  102 , shown in  FIGS. 1 ,  2 ,  4  and  5 , to which several components of printer  100  are mounted. The swing arm assembly  102  is preferably covered by a cover  302  of housing  102 , as shown in  FIG. 1 . The swing arm assembly  102  includes a closed position shown in  FIGS. 1 and 4 , and an open or raised position shown in  FIGS. 2 and 5 . The swing arm assembly  102  is maintained in the closed position by a suitable latching mechanism  304  that can be released by actuation of a handle  306 . When the swing arm assembly  102  is in the raised position, the printhead  112  preferably automatically moves to the withdrawn position  196  and the operator can load the print and image transfer ribbons  108  and  114  into printer  100  as well as gain access to other components of printer  100 . 
   The swing arm assembly  102  generally includes a swing frame having a pair of side walls  310  and  312 , to which components of the swing arm assembly  102  are mounted, such as drive rollers, gears, ribbon guides, ribbon sensors, and other components. Additionally, the transfer ribbon supply spool  124  is mounted to the swing arm assembly  102 , as shown in the side views of  FIGS. 4 and 5  where the front side wall is removed. 
   In accordance with one embodiment of the invention, the swing frame of the swing arm assembly  102  is mounted between the side walls  101  of the printer frame, such that it rotates about an axis of rotation of the transfer ribbon take-up spool  126  as defined by a first ribbon roll support, such as the transfer ribbon hubs  320 , shown in  FIG. 13 , which is a partial exploded perspective view of the printer  100  at the card output  150 . This configuration simplifies the installation of the image transfer ribbon  114  by preventing the development of excessive slack or tension in the image transfer ribbon  114  by maintaining a constant relative position between the transfer ribbon supply spool  124  and the transfer ribbon take-up spool  126  during the closing of the swing arm assembly  102 . 
   One embodiment of the swing arm assembly  102  includes a notch  322  in the side walls  310  and  312  that rest on the shafts  324  and  325  of the transfer ribbon take-up hubs  320  that are mounted to the side walls  101  of the printer frame. Brackets  326  include an aperture  328  through which the corresponding shaft  325  or  324  extends. Once the notches  322  of swing arm assembly side walls  310  and  312  are placed on the shafts  324  and  325 , the brackets  326  are mounted to the side walls  310  and  312  with screws  330  or other suitable fasteners. The brackets  326  can also include one or more slot features  332  that receive edges  334  of the side walls  310  and  312  of swing arm assembly  102  to assist in the proper mounting of the side walls  310  and  312  of the swing arm assembly  102  to the brackets  326 . 
   Swing Arm Brake 
   Another embodiment of the invention is directed to a swing arm brake  350  that resists rotation of the swing arm assembly  102  to assist in maintaining the swing arm assembly  102  in the opened position, and to prevent the swing arm assembly  102  from crashing to the closed position. Embodiments of the brake  350  are shown in the exploded perspective view of  FIG. 13 , and in the simplified partial front assembled view of the brake  350  of  FIG. 14 . The brake  350  includes one or more disc members, such as disc members  352  and  354 , that are mounted to the sides of at least one of the brackets  326  of the swing arm assembly  102 . A screw  356 , or other suitable member, extends through a side wall  101  of the printer frame and a slot  358  in the bracket  326 . The screw  356  also extends through the disc member  352  that is positioned between the side wall  312  and the bracket  326 , and the disc member  354  that is positioned between the bracket  326 . Washers  360  and nuts  362  ( FIG. 14 ) can be used to complete the installation of the brake  350 . 
   The material forming the disc members  352  and  354  is selected to provide the desired frictional resistance against the bracket  326  to resist rotation of the swing arm assembly  102 , and is preferably plastic (such as Delrin®), rubber or other suitable material. The frictional resistance can be adjusted by tightening or loosening the screw  356  to respectively increase or decrease the pressure applied to the bracket  326  by members  352  and  354 . Alternatively, a spring  364  can be positioned between the disc member  352  and the side wall  101 , for example, to produce the desired frictional resistance to the rotation of the bracket  326  and the swing arm assembly  102 , as shown in  FIG. 14 . 
   Card Guide 
   It is critical that the card substrates  186  that are fed from the input  148  are properly aligned with the printed transfer panel  130  during the image transfer operation to ensure that the image is properly positioned on the surface  188  of the card  186 . One embodiment of the present invention is directed to a card guide  370 , shown in the exploded and assembled perspective views of  FIGS. 15 and 16 , respectively.  FIG. 17  is a cross-sectional view of the card guide  370  that is generally taken along line  17 - 17  of  FIG. 16 , but with the addition of top guide rollers  185  of the card transfer mechanism  184  and a card  186 . 
   The card guide  370  is generally positioned in the card path  146  and operates to align the card  186  horizontally with the printed image at the image transfer section  106 , as shown in  FIGS. 3-5 . One or more card sensors  371  ( FIGS. 15 and 16 ), such as optical sensors, are generally used to detect a leading edge of the card  186  such that the controller  119  can align the card longitudinally with the printed image. 
   The card guide  370  includes side guide members  372  and  374  that are joined together by a base member  376  to prevent relative movement therebetween. As a result, the side guide members  372  and  374  are fixed in a predetermined position relative to each other and are spaced to receive cards  186  having a standardized card width. The card guide  370  is installed in printer  100  such that the side guide members  372  and  374  extend through slots  377  in a bottom plate  378  that forms a portion of the printer or base frame of the printer  100 . 
   The position of the card guide  370  is preferably adjustable relative to the bottom plate  378  in accordance with the size of the slots  377  and is fixed in place using suitable fasteners  379  that extend through tabs  380  of the card guide  370 . A receiving end  381  of the card guide  370  can include flared tabs  382  and  384  that assist in the receiving of the transported cards  186  between the side guide members  372  and  374 . The receiving end  380  is positioned adjacent the input  148  of printer  100  to receive cards  186  fed directly from, for example, a card flipper  385  or a card hopper  386  shown in  FIGS. 4 and 5 , a user of printer  100 , or from another card processing device. 
   Portions of lower rollers  185  extend through the bottom plate  378  and openings  390  in the base member  376  of the card guide  370 . The rollers  185  are supported within notches  392  by members  394 . Notches  396  formed along the top edge of the side guide members  372  and  374  receive the shafts of upper rollers  185  to form pinch roller pairs along the card path  146 . Preferably the top rollers  185  are motorized to drive the card along the print path  146 . 
   As the card  186  is fed through the card guide  370  from the receiving end  380  in the direction indicated by arrow  398  ( FIG. 17 ) the card engages flexible card bumpers  400  and  402 , which are attached to the card guide  370  and extend through openings  404  and  406 , respectively, of side guide member  374 . The card bumpers  400  and  402  operate to press the card  186  against the inside of side guide member  372  and provide the desired accurate positioning of the card relative to the printed transfer panel  130  of the transfer ribbon  114 . 
   The card  186  is eventually fed through a card discharge end  408  and on to the heated transfer roller  180  of the image transfer section  106 . A slot  410  is formed in the plate  378 , through which the platen  182  extends. The printed image on a panel  130  of the transfer ribbon  114  is aligned with the card  186  using the card sensor  371  and the ribbon sensor  252 , as described above. The card  186  is fed between the printed panel  130  and the platen  182  as heat and pressure is applied by the heated transfer roller  180  to transfer the image to the surface  188  of the card  186 . 
   The printed card  186  is received by feed rollers  185  at a second card guide  411  from the heated transfer roller  180  and preferably fed to a card bender, as will be discussed below. 
   Card Bender 
   The transferring of the image from the printed transfer ribbon panel  130  to the surface  188  of the card  186  causes the card  186  to bend such that the surface  188  becomes concave. One embodiment of printer  100  includes a card bender  412 , which is shown assembled in  FIGS. 3 and 13 .  FIG. 18  is an exploded perspective view of the card bender  412  at the card output  150  of the printer  100 . The card bender  412  is configured to receive the bent card  186  and straighten the card  186  by temporarily reversing the bend (i.e., temporarily making surface  188  convex). 
   Card bender  402  generally includes first and second rollers  414  and  416  that form a pinch roller pair. The first roller  414  is positioned above the second roller  416 , either of which can be driven by a motor  417 . A bracket  418  mounts to the axle  419  of the second guide roller  416  and supports the axle  420  of the first guide roller  414  in slots  422  for slidable movement away from and toward second guide roller  416 . In accordance with one embodiment of the invention, a biasing mechanism, such as springs  423  or other suitable members, bias the first roller  414  toward the second roller  416 , while allowing the first roller  414  to deflect slightly away from the second roller  416  in order to receive the card  186 . 
   The bracket  418  can be rotated about the axle  419  of the second guide roller  416  to change the angular position of the first roller  414  relative to the second roller  416 . The bracket  418  can be secured in place by a thumb screw  424  ( FIG. 18 ) that attaches the bracket  418  to the side wall  101  of the printer frame, or otherwise fixed in a desired position. A plane  426  that extends parallel to an through the axes of rotation of the first and second rollers  414  and  416  is at an angle  428  that is non-perpendicular to the substantially horizontal card path  146  that is aligned at the output  150  with the tangent of both the feed rollers  185  of the pinch roller pair or assembly  430 , as shown in  FIG. 3 . As the bracket  418  is rotated in the direction indicated by the arrow  432  ( FIG. 3 ) the more severe the downward bend the card bender  412  will apply to the card  186  as the card  186  is discharged along the tangent to both the first and second rollers  414  and  416 , or perpendicularly to the plane  426 . 
   In operation, the card bender  412  receives the bent card  186 , which is aligned by the card guide  411  and fed by the pinch rollers  185  or other feed mechanism near the output  150 . While the trailing portion of the card  186  is still in the grasp of the pinch roller assembly  430 , or maintained in the card path  146  by another suitable card support, the leading portion of the card  186  is directed downwardly in accordance with the angle  428 . When adjusted properly, the card bender  412  will eject a substantially straight card  186 . The card  186  can then be discharged through the output  150  and into a card hopper or passed to another card processing device for additional processing. 
   Although the present invention has 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 invention.