Abstract:
A method of reducing or eliminating dye build-up on tension rollers in a thermal printing system is presented. The thermal printing system comprises a station capable of depositing black dye on a media. The method comprises the steps of depositing the black dye on the media and processing the black dye prior to the black dye reaching the tension roller. Processing the black dye includes techniques, such as cooling the black dye, re-routing the black dye, and drying the black dye before the black dye comes in contact with the tension rollers.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates generally to the field of printers and in particular to thermal printers. More specifically, the invention relates to a method and apparatus for reducing and/or eliminating dye build-up on tension rollers in a thermal printer.  
       BACKGROUND OF THE INVENTION  
       [0002]     A conventional thermal printer includes a number of stations for delivering color to a media using a dye or other types of delivery mechanism. During operation, a specific location on a media, such as paper, is moved from one station to another and each station is capable of depositing dye on the media at the specific location. A microprocessor controls the amount of dye deposited from each station and as such, a variety of colors may be realized on the media.  
         [0003]     In a thermal printer, each station includes a thermal head that uses heat to transfer a dye from a donor ribbon onto the media. Transferring the dye from the donor ribbon onto the media registers an impression on the media. When one or more stations deposit different dyes on the media at the same location, a variety of colors may be realized on the media. After each station has deposited the dye on the media, a final station deposits a clear coat on the media to safeguard the dye deposited on the media. In addition to protecting the dye deposited on the media, the clear coat often has a reflective quality that enhances the impression registered on the media producing enhanced colors.  
         [0004]     As conventional thermal printers advance, a variety of techniques are developing to produce enhanced colors. As a result of size limitations, cost limitations, etc., a number of these techniques require the removal of the final station that applies the clear coat. Without the clear coat, any excess dye deposited on the media may build-up on other structures and/or devices in the thermal printer. Dye may build-up (i.e., dye build-up) on devices or structures that come in contact with the media after the dye has been deposited on the media. For example, tension rollers engage the media and may come in contact with the dye if there is no clear coat to separate the tension rollers from the dye. As a result, dye build-up may develop on the tension rollers. Once the dye build-up on devices, such as the tension rollers become too great, the devices may re-deposit the dye build-up back onto the media. Re-depositing the dye build-up back onto the media may ultimately destroy the initial impression registered on the media.  
         [0005]     Thus, there is a need for a method and apparatus for producing enhanced colors in thermal printing systems. There is a need for a method and apparatus for reducing and/or illuminating dye build-up in thermal printing systems.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a method is presented for reducing dye build-up on tension rollers operating in a thermal printing system. The thermal printing system comprises a station capable of depositing black dye on a media. The method comprises the steps of depositing the black dye on the media and processing the black dye prior to the black dye reaching the tension rollers. It should be appreciated that processing the black dye includes a number of techniques designed to reduce and/or eliminate the build-up of the black dye on the tension rollers.  
         [0007]     In one embodiment, the step of processing the black dye prior to the black dye making contact with the tension rollers comprises the step of rerouting the black dye prior to the black dye engaging the tension rollers. For example, a donor ribbon used to transfer the black dye to the media is routed around a tension roller to avoid dye build-up on the tension roller.  
         [0008]     In a second embodiment, the step of processing the black dye prior to the black dye making contact with the tension rollers includes the step of drying the black dye prior to the black dye engaging the tension rollers. For example, a blotting roller is positioned between a station capable of depositing black dye and a tension roller to absorb any excess dye on the media.  
         [0009]     In a third embodiment, the step of processing the black dye prior to the black dye making contact with the tension rollers includes the step of cooling the black dye prior to the black dye engaging the tension rollers. For example, an airflow mechanism is positioned to direct air toward a media after dye has been deposited on the media but prior to the dye reaching the tension rollers. In alternative embodiments, cooling may be accomplished using a Peltier device to generate a cold region and dry the black dye using chilled water to generate a cold region and dry the black dye, etc.  
         [0010]     Lastly, in another embodiment, processing the black dye prior to the black dye making contact with the tension rollers includes the step of providing enough spacing between the station that deposits the black dye and the tension rollers so that the black dye will dry prior to reaching the tension rollers.  
         [0011]     Briefly summarized according to a second aspect of the present invention, a method and apparatus for enhancing color in a thermal printing system is presented. In one embodiment, a station capable of depositing black dye on a media is implemented in a thermal printer system to produce enhanced colors.  
         [0012]     The above and other objects of the present invention will become more apparent when taken in conjunction with the following description and drawings wherein identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. These and other aspects, objects, features, and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.  
         [0013]     The present invention details advantageous techniques for enhancing the color produced by a thermal printer. In addition, the present invention includes advantageous techniques for reducing dye build-up on tension rollers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is an embodiment of a thermal printing system including a station capable of depositing black dye on a media;  
         [0015]      FIG. 2  is an embodiment of a thermal printing system including a mechanism for rerouting a donor ribbon;  
         [0016]      FIG. 3  is an embodiment of a thermal printing system including a mechanism for drying excess dye;  
         [0017]      FIG. 4  is an embodiment of a thermal printing system including a mechanism for cooling excess dye; and  
         [0018]      FIG. 5  is an embodiment of a thermal printing system including appropriate spacing to dry excess dye. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     In the following description, the present invention will be described in the preferred embodiment as a software program. Those skilled in the art will readily recognize that the equivalent of such software may also be constructed in hardware.  
         [0020]      FIG. 1  is an embodiment of a thermal printing system including a station capable of depositing black dye on a media. Referring to  FIG. 1 , a thermal printing system  100  is shown. A lower tension roller  102  is shown positioned relative to an upper tension roller  106  so that the lower tension roller  102  in combination with the upper tension roller  106  apply a compressive force to a media  104 . In one embodiment, tension roller  102  moves in a direction indicated by directional arrow  110  and tension roller  102  moves in a direction indicated by directional arrow  110 . The combination of lower tension roller  102  and upper tension roller  106  pull the media  104  through the thermal printing system  100 .  
         [0021]     A station  114 , a station  116 , a station  118 , and a station  120  are positioned in the thermal printing system  100  to deposit a dye on the media  104 . It should be appreciated that a station may include any system or mechanism used to deposit dye on the media  104 . Although stations employing thermal technology are discussed and described, the scope of the present invention is beyond thermal technology. It should also be appreciated that the term “dye” and/or the phrase “depositing a dye” is used to describe the scenario where ink, wax, or some other transfer material or mechanism is used by the station (i.e.,  114 ,  116 ,  118 ,  120 ) to deposit a color on the media  104 .  
         [0022]     Each station (i.e.,  114 ,  116 ,  118 ,  120 ) is positioned relative to a support roller (i.e.,  130 ,  146 ,  166 ,  186 ) to move the media  104  through the thermal printing system  100  and deposit dye on the media  104 . For example, support roller  130  is positioned relative to station  114  to process the media  104 . Support roller  146  is positioned relative to the station  116  to process the media  104 . Support roller  166  is positioned relative to station  118  to process the media  104 . Lastly, support roller  186  is positioned relative to station  120  to process the media  104 .  
         [0023]     In one embodiment, the station  114  includes a donor ribbon supply  122  and a donor ribbon take-up  136 . A thermal head  128  is positioned relative to the donor ribbon supply  122  and the donor ribbon take-up  136  to receive donor ribbon  124  and utilize donor ribbon  124  to deposit dye on the media  104 . On an opposite side of thermal head  128 , donor ribbon  124  is collected by donor ribbon take-up  136 . For the purposes of discussion, the donor ribbon collected by donor ribbon take-up  136  will be referred to as “take-up ribbon.” For example, items  132 ,  150 ,  170 ,  190 , and other items collected by a donor ribbon take-up will be referred to as a take-up ribbon. In addition, a support roller  130  is shown positioned on an opposite side of the media  104  from the thermal head  128 .  
         [0024]     During operation of the thermal printing system  100 , the media  104  is pulled through the thermal printing system  100  by the tension rollers  102  and  106 . During operation of the station  114 , the media  104  is positioned between the thermal head  128  and the support roller  130 . Donor ribbon  124  is supplied by the donor ribbon supply  122  and moves toward the thermal head  128  as shown by directional arrow  126 . The donor ribbon  124  is positioned between the thermal head  128  and the media  104 , where the thermal head  128  utilizes the donor ribbon  124  to deposit a dye on the media  104 . Take-up ribbon  132  moves in a direction denoted by directional arrow  134  and is collected by donor ribbon take-up  136 .  
         [0025]     During operation, the donor ribbon  124  is positioned between the thermal head  128  and the media  104 . The thermal head  128  is heated and deposits the dye on the media  104 . In one embodiment, the station  114  is capable of depositing a black dye on the media  104 . For example, donor ribbon  124  is implemented as a black donor ribbon  124 . As such, when the thermal head  128  is heated, black dye is deposited on the media  104 .  
         [0026]     A station  116  includes a donor ribbon supply  140  and a donor ribbon take-up  154 . A thermal head  148  is positioned relative to the donor ribbon supply  140  and the donor ribbon take-up  154  to receive donor ribbon  144  and utilize donor ribbon  144 . Take-up ribbon  150  is then collected at donor ribbon take-up  154 . A support roller  146  is positioned on an opposite side of the media  104  from the thermal head  148 . Further, the donor ribbon  144  is positioned between the thermal head  148  and the media  104 . In one embodiment, the station  116  is capable of depositing cyan colored dye on the media  104 .  
         [0027]     During operation of station  116 , the media  104  is positioned between the thermal head  148  and the support roller  146 . Donor ribbon  144  is supplied by the donor ribbon supply  140  and moves toward the thermal head  148  as shown by directional arrow  142 . The donor ribbon  144  is positioned between the thermal head  148  and the media  104 , where the thermal head  148  utilizes the donor ribbon  144  to deposit a dye stored on the donor ribbon  144  on the media  104 . Take-up ribbon  150  moves in a direction denoted by directional arrow  152  and is collected by donor ribbon take-up  154 .  
         [0028]     During operation, the donor ribbon  144  is positioned between the thermal head  148  and the media  104 . The thermal head  148  is heated and deposits a dye on the media  104 . In one embodiment, the station  116  is capable of depositing a cyan colored dye on the media  104 . For example, donor ribbon  144  is implemented as a cyan donor ribbon  144 . As such, when the thermal head  148  is heated, the color cyan is deposited on the media  104 .  
         [0029]     A station  118  includes a donor ribbon supply  160  and a donor ribbon take-up  174 . A thermal head  168  is positioned relative to the donor ribbon supply  160  and the donor ribbon take-up  174  to receive donor ribbon  164  and utilize donor ribbon  164 . Take-up ribbon  170  is then collected at donor ribbon take-up  174 . A support roller  166  is positioned on an opposite side of the media  104  from the thermal head  168 .  
         [0030]     During operation of the station  118 , the media  104  is positioned between the thermal head  168  and the support roller  166 . Donor ribbon  164  is supplied by the donor ribbon supply  160  and moves toward the thermal head  168  as shown by directional arrow  162 . The donor ribbon  164  is positioned between the thermal head  168  and the media  104 , where the thermal head  168  utilizes the donor ribbon  164  to deposit a dye on the media  104 . Take-up ribbon  170  moves in a direction denoted by directional arrow  172  for collection by the donor ribbon take-up  174 .  
         [0031]     During operation, the donor ribbon  164  is positioned between the thermal head  168  and the media  104 . The thermal head  168  is heated and deposits dye on the media  104 . In one embodiment, the station  118  is capable of depositing a magenta dye on the media  104 . For example, donor ribbon  164  is implemented as a magenta donor ribbon  164 . As such, when the thermal head  168  is heated, a magenta dye is deposited on the media  104 .  
         [0032]     A station  120  includes a donor ribbon supply  180  and a donor ribbon take-up  194 . A thermal head  188  is positioned relative to the donor ribbon supply  180  and the donor ribbon take-up  194  to receive donor ribbon  184  and utilize donor ribbon  184 . Take-up ribbon  190  is then collected at donor ribbon take-up  194 . A support roller  186  is positioned on an opposite side of the media  104  from the thermal head  188 .  
         [0033]     During operation of the station  120 , the media  104  is positioned between the thermal head  188  and the support roller  186 . Donor ribbon  184  is supplied by the donor ribbon supply  180  and moves toward the thermal head  188  as shown by directional arrow  182 . The donor ribbon  184  passes between the thermal head  188  and the media  104 , where the thermal head  188  utilizes the donor ribbon  184  to deposit a dye stored on the donor ribbon  184  on the media  104 . A take-up ribbon  190  moves in a direction denoted by directional arrow  192  for collection by the donor ribbon take-up  194 .  
         [0034]     During operation of the station  120 , donor ribbon  184  is positioned between the thermal head  188  and the media  104 . The thermal head  188  is heated and deposits dye on the media  104 . In one embodiment, the station  120  is capable of depositing a yellow dye on the media  104 . For example, donor ribbon  184  is implemented as a yellow donor ribbon  184 . As such, when the thermal head  188  is heated, a yellow dye is deposited on the media  104 .  
         [0035]     During operation of the thermal printing system  100 , the media  104  is positioned between the tension rollers  102  and  106 , thermal head  128  and support roller  130 , thermal head  148  and support roller  146 , thermal head  168  and support roller  166 , and thermal head  188  and support roller  186 . As tension roller  102  rotates as shown by directional arrow  110  and tension roller  106  rotates as shown by directional arrow  112 , the media  104  is pulled through the thermal printing system  100  in a direction shown by arrow  108 . As the media is drawn through the thermal printing system  100 , each station  114 ,  116 ,  118 , and  120  is capable of depositing dye on the media  104  at the same location or at a different location. For example, in one embodiment of the thermal printing system  100 , station  114  is capable of depositing black dye on media  104 , station  116  is capable of depositing cyan dye on media  104 , station  118  is capable of depositing magenta dye on media  118 , and station  120  is capable of depositing yellow dye on media  104 . Each station (i.e.,  114 ,  116 ,  118 ,  120 ) deposits dye on the media  104  at a predefined location and in the quantities necessary to realize a final color or picture on the media  104 . For example, each station (i.e.,  114 ,  116 ,  118 ,  120 ) may deposit predefined amount of dye on the same location on the media  104  to produce the color red, green purple, etc. Further, in accordance with one embodiment of the present invention, the final station, station  114 , is implemented with a black dye to deliver black color. As such, in accordance with one objective of the present invention, enhanced colors are produced by the thermal printing system  100 .  
         [0036]      FIG. 2  is an embodiment of a thermal printing system including a mechanism for rerouting a donor ribbon.  FIG. 2  displays one embodiment in which a take-up ribbon is routed around an upper tension roller prior to collection by the donor ribbon take-up. As such, in accordance with the teachings of the present invention, dye build-up on the tension rollers is reduced or eliminated.  
         [0037]     Referring to  FIG. 2 , a thermal printing system  200  is shown. The thermal printing system  200  includes a lower tension roller  206  positioned below media  204  and an upper tension roller  208  positioned above the media  204 . In one embodiment, the lower tension roller  206  and the upper tension roller  208  are positioned to apply compressive force to the media  204  and move the media  204  through the thermal printing system  200 .  
         [0038]     A plurality of stations  230 ,  240   250 , and  260  are shown. Support rollers  222 ,  242 ,  252 , and  262  are positioned on an opposite side of the media  204  from the stations  230 ,  240 ,  250 , and  260 .  
         [0039]     In one embodiment, the station  230  includes a donor ribbon supply  216 . Thermal head  224  is positioned so that donor ribbon  220  may be routed from the donor ribbon supply  216  to the thermal head  224 . The upper tension roller  208  is positioned so that the take-up ribbon  229  may be conveyed along with the media  204  to the upper tension roller  208  as shown by directional arrow  228  and directional arrow  218 . A magnified view  234  of an area denoted as  226  displays take-up ribbon  229  and the media  204 . The upper tension roller  208  is positioned relative to the thermal head  224  and to the donor ribbon take-up  214  so that the take-up ribbon  229  may be routed around the upper tension roller  208  and then collected by the donor ribbon take-up  214 . The donor ribbon take-up  214  is positioned to collect the take-up ribbon  229  after the take-up ribbon  229  is routed around the upper tension roller  208 . In accordance with the teachings of the present invention, routing the take-up ribbon  229  around the upper tension roller  208  reduces or eliminates the build-up of dye material on the upper tension roller  208 .  
         [0040]     During operation of the thermal printing system  200 , the media  204  is positioned between the station  260  and the support roller  262 , the station  250  and the support roller  252 , the station  240  and the support roller  242 , the station  230  and the support roller  222 , and the upper tension roller  208  and the lower tension roller  206 . In one embodiment, the lower tension roller  206  rotates as shown by directional arrow  210  and the upper tension roller  208  rotates in a direction as shown by directional arrow  212 . As the tension rollers ( 206 ,  208 ) rotate, the media  204  is pulled through the thermal printing system  200  in a direction shown by arrow  202 . As the media is pulled through the thermal printing system  200 , station  260  may deposit yellow dye on the media  204 , station  250  may deposit magenta dye media on the media  204 , station  240  may deposit cyan dye on the media  204 , and station  230  may deposit black dye on the media  204 .  
         [0041]     In one embodiment, donor ribbon  220  is supplied by donor ribbon supply  216  and positioned between thermal head  224  and support roller  222 . Specifically, donor ribbon  220  is positioned between thermal head  224  and media  204 . Station  230  may utilize donor ribbon  220  to deposit dye on media  204 . In one embodiment, take-up ribbon  229  is then routed in the same direction as the media  204  as shown by directional arrow  228 . The take-up ribbon  229  is then routed around upper tension roller  208 . Subsequent to routing the take-up ribbon  229  around the upper tension roller  208 , the take-up ribbon  229  is routed to the donor ribbon take-up  214  as shown by directional arrow  232 . In accordance with the teachings of the present invention, since the take-up ribbon  229  is positioned around the upper tension roller  208 , the dye build-up on the upper tension roller  208  is reduced or eliminated.  
         [0042]      FIG. 3  is an embodiment of a thermal printing system including a mechanism for drying excess dye. Referring to  FIG. 3 , a thermal printing system  300  including a blotter roller  310  is shown. The thermal printing system  300  includes a lower tension roller  306  positioned below media  304  and an upper tension roller  308  positioned above the media  304 . In one embodiment, the lower tension roller  306  and the upper tension roller  308  are positioned to apply compressive force to the media  304  and rotate to pull media  304  through the thermal printing system  300 . A plurality of stations  314 ,  318 ,  322 , and  326  are shown. Each station (i.e.,  314 ,  318 ,  322 ,  326 ) is capable of depositing a dye on the media  304 . Support rollers  312 ,  316 ,  320 , and  324  are disposed on an opposite side of the media  304  from the stations  314 ,  318 ,  322  and  326 , respectively. In one embodiment, blotting roller  310  is positioned between the upper tension roller  308  and station  314 . It should be appreciated that blotting roller  310  may include any absorption mechanism for removing excess dye deposited by any one of the stations  314 ,  318 ,  322 ,  326 . Additionally, it may include a cleaning means through the application of a cleaning agent, such as alcohol.  
         [0043]     During operation of the thermal printing system  300 , the media  304  is positioned between the station  326  and the support roller  324 , the station  322  and the support roller  320 , the station  318  and the support roller  316 , the station  314  and the support roller  312 , and the upper tension roller  308  and the lower tension roller  306 . As the tension rollers ( 306 ,  308 ) rotate, the media  304  is pulled through the thermal printing system  300  in a direction shown by arrow  302 . As the media  304  is moved through the thermal printing system  300 , station  326  may deposit yellow dye on the media  304 , station  322  may deposit magenta dye on the media  304 , station  318  may deposit cyan dye on the media  304 , and station  314  may deposit black dye on the media  304 . It should be understood by those skilled in the art that these dyes may be deposited in other desired sequences of colors due to individual engineering needs.  
         [0044]     In one embodiment, after station  314 , the blotting roller  310  makes contact or engages the media  304  to absorb or likewise remove any excess dye from the media. For example, after the media  304  moves beyond the last station (i.e., station  314 ) in the thermal printing system  300 , placing the blotting roller  310  in contact with the media  304  would ensure that any excess dye deposited on the media  304  from any station (i.e.,  326 ,  322 ,  318 ,  314 ) is reduced and/or removed.  
         [0045]      FIG. 4  is an embodiment of a thermal printing system including a mechanism for cooling excess dye. Referring to  FIG. 4 , a thermal printing system  400  including a cooling mechanism is shown. The thermal printing system  400  includes a lower tension roller  406  positioned below media  404  and an upper tension roller  408  positioned above the media  404 . In one embodiment, the lower tension roller  406  and the upper tension roller  408  are positioned to apply compressive force to the media  404 . A plurality of stations  414 ,  418 ,  422 , and  426  are shown. Supports rollers  412 ,  416 ,  420 , and  424  are disposed on an opposite side of the media  404  from the stations  414 ,  418 ,  422  and  426 .  
         [0046]     A cooling mechanism  410  is implemented to cool excess dye. In one embodiment, the cooling mechanism  410  generates a cold region  409  in the direction shown by directional arrow  411  to dry excess dye. In accordance with the teachings of the present invention, the cooling mechanism  410  represents any mechanism that may be used to generate a cold region  409 . For example, the cooling mechanism  410  may be implemented with a fan, a Peltier device, a chilled water generator, etc.  
         [0047]     In one embodiment, the cooling mechanism  410  is implemented with an airflow mechanism, such as a fan. In one embodiment, the airflow mechanism (i.e., the cooling mechanism  410 ) is positioned between the upper tension roller  408  and the station  414  closest to the upper tension roller  408 . However, it should be appreciated that the airflow mechanism (i.e., the cooling mechanism  410 ) may be positioned in any location suitable for directing air toward the media  404  after the media  404  has moved beyond station  414 .  
         [0048]     During operation of the thermal printing system  400 , the media  404  is positioned between the station  426  and the support roller  424 , the station  422  and the support roller  420 , the station  418  and the support roller  416 , the station  414  and the support roller  412 , and the upper tension roller  408  and the lower tension roller  406 . As the tension rollers ( 406 ,  408 ) rotate, the media  404  is pulled through the thermal printing system  400  in a direction shown by arrow  402 . As the media is moved through the thermal printing system  400 , station  426  may deposit dye on the media  404 , station  422  may deposit dye on the media  404 , station  418  may deposit dye on the media  404 , and station  414  may deposit dye on the media  404 .  
         [0049]     In one embodiment, after the last station before the upper tension roller  408  (i.e.,  414 ) delivers a dye to the media  404 , the cooling mechanism  410  generates a cold region  409  as shown by directional arrow  411  in the direction of the media  404 . Excess dye on the media  404  is air-cooled by the cold region  409  generated by the cooling mechanism  410  prior to the excess dye reaching the upper tension roller  408 . As such, in accordance with the teachings of the present invention, dye build-up on the upper tension roller  408  is reduced or eliminated.  
         [0050]     As mentioned previously, a variety of alternative mechanisms may be used to implement the cooling mechanism  410  and generate the cold region  409 . For example, the cooling mechanism  410  may be implemented with a Peltier device (i.e., cooling mechanism) or chilled water generator. In one embodiment, a Peltier device (i.e., cooling mechanism  410 ) or an appendage attached to a Peltier device (i.e., cooling mechanism  410 ) may generate the cold region  409 . The cold region  409  or an appendage generating the cold region  409  may be placed in contact with the dye and cool and/or dry the excess dye. In an alternate embodiment, the Peltier device (i.e., cooling mechanism  410 ) may generate the cold region  409  in proximity to the dye on media  404  and as a result, cool and/or dry the excess dye.  
         [0051]     A chilled water generator (i.e., cooling mechanism  410 ) may be used to generate the cold region  409  and cool and/or dry excess dye. For example a chilled water generator (i.e., cooling mechanism  410 ) may produce chilled water that generates the cold region  409  and is then used to cool or dry the excess dye. In the alternative, the chilled water generator (i.e., cooling mechanism  410 ) may connect to an appendage that generates the cold region  409  and/or is placed in contact or within proximity of the dye to cool and/or dry the dye. It should be appreciated that the cooling mechanism may be positioned in a variety of locations in the thermal printing system  410 . For example, a Peltier device may be positioned at an alternate location in the thermal printing system  400  and then an appendage may be used to generate a cold region  409 , in the area of the dye.  
         [0052]      FIG. 5  is an embodiment of a thermal printing system including appropriate spacing to dry excess dye. Referring to  FIG. 5 , a thermal printing system  500  including spacing between the tension rollers and the stations is shown. The thermal printing system  500  includes a lower tension roller  506  positioned below media  504  and an upper tension roller  508  positioned above the media  504 . In one embodiment, the lower tension roller  506  and the upper tension roller  508  are positioned to apply compressive force to the media  504 . A plurality of stations  514 ,  518 ,  522 , and  526  are shown. Supports rollers  512 ,  516 ,  520 , and  524  are disposed on an opposite side of the media  504  from the stations  514 ,  518 ,  522  and  526 . In one embodiment, spacing is shown between the upper tension roller  508  and the station  514  closest to the upper tension roller  508 . In one embodiment, the spacing  510  is defined such that when dye is deposited on the media  504  by station  514  enough spacing  510  is provided between station  514  and the upper tension roller  508  so that the dye deposited by station  514  dries before the dye reaches the upper tension roller  508 . As such, in accordance with the teachings of the present invention, the dye build-up on the upper tension roller  508  is reduced or eliminated.  
         [0053]     During operation of the thermal printing system  500 , the media  504  is positioned between the station  526  and the support roller  524 , the station  522  and the support roller  520 , the station  518  and the support roller  516 , the station  514  and the support roller  512 , and the upper tension roller  508  and the lower tension roller  506 . As the tension rollers ( 506 ,  508 ) rotate, the media  504  is moved through the thermal printing system  500  in a direction shown by arrow  502 . As the media  504  is pulled through the thermal printing system  500 , station  526  may deposit dye on the media  504 , station  522  may deposit dye on the media  504 , station  518  may deposit dye on the media  504 , and/or station  514  may deposit dye on the media  504 .  
         [0054]     In one embodiment, after the last station (i.e.,  514 ) deposits a dye to the media  504 , the spacing  510  is defined so that any excess dye on the media  504  dries prior reaching the upper tension roller  508 . As such, dye build-up on the upper tension roller  508  will be eliminated or reduced. It should be appreciated that the spacing  510  may depend on a number of variables. For example, the spacing  510  may depend on the speed that the media  504  moves through the thermal printing system  500 , the temperature required to dry excess dye, the amount of excess dye deposited on the media  504 , the ability of the media  504  to absorb the excess dye, etc.  
         [0055]     The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention.  
       Parts List  
       [0000]    
       
           100  thermal printing system  
           102  lower tension roller  
           104  media  
           106  upper tension roller  
           108  directional arrow  
           110  directional arrow  
           112  directional arrow  
           114  station  
           116  station  
           118  station  
           120  station  
           122  donor ribbon supply  
           124  donor ribbon  
           126  directional arrow  
           128  thermal head  
           130  support roller  
           132  take-up ribbon  
           134  directional arrow  
           136  donor ribbon take-up  
           140  donor ribbon supply  
           142  directional arrow  
           144  donor ribbon  
           146  support roller  
           148  thermal head  
           150  take-up ribbon  
           152  directional arrow  
           154  donor ribbon take-up  
           160  donor ribbon supply  
           162  directional arrow  
           164  donor ribbon  
       
     
       Parts List (Continued)  
       [0000]    
       
           166  support roller  
           168  thermal head  
           170  take-up ribbon  
           172  directional arrow  
           174  donor ribbon take-up  
           180  donor ribbon supply  
           182  directional arrow  
           184  donor ribbon  
           186  support roller  
           188  thermal head  
           190  take-up ribbon  
           192  directional arrow  
           194  donor ribbon take-up  
           200  thermal printing system  
           202  directional arrow  
           204  media  
           206  lower tension roller  
           208  upper tension roller  
           210  directional arrow  
           212  directional arrow  
           214  donor ribbon take-up  
           216  donor ribbon supply  
           218  directional arrow  
           220  donor ribbon  
           222  support roller  
           224  thermal head  
           226  denoted area  
           228  directional arrow  
           229  take-up ribbon  
           230  station  
           232  directional arrow  
       
     
       Parts List (Continued)  
       [0000]    
       
           234  magnified view  
           240  station  
           242  support roller  
           250  station  
           252  support roller  
           260  station  
           262  support roller  
           300  thermal printing system  
           302  directional arrow  
           304  media  
           306  lower tension roller  
           308  upper tension roller  
           310  blotting roller  
           312  support roller  
           314  station  
           316  support roller  
           318  station  
           320  support roller  
           322  station  
           324  support roller  
           326  station  
           400  thermal printing system  
           402  directional arrow  
           404  media  
           406  lower tension roller  
           408  upper tension roller  
           409  cold region  
           410  cooling mechanism  
           411  directional arrow  
           412  support roller  
           414  station  
       
     
       Parts List (Continued)  
       [0000]    
       
           416  support roller  
           418  station  
           420  support roller  
           422  station  
           424  support roller  
           426  station  
           500  thermal printing system  
           502  directional arrow  
           504  media  
           506  lower tension roller  
           508  upper tension roller  
           510  spacing  
           512  support roller  
           514  station  
           516  support roller  
           518  station  
           520  support roller  
           522  station  
           524  support roller  
           526  station