Patent Publication Number: US-6698958-B2

Title: Sublimation system and method

Description:
FIELD OF INVENTION 
     This invention relates to a printing system and, more particularly, the invention relates to a process and apparatus for sublimating at least one sublimable dye on a substrate carrier that may be cut to provide a plurality of labels. 
     DESCRIPTION OF RELATED ART 
     In the past, printed fabric labels were made using a variety of well-known techniques, such as screen printing, off set lithography printing, dying, flexographic printing, thermal printing, ink jet printing, and the like. Several prior art methods and apparatuses for printing are disclosed in U.S. Pat. Nos. 4,776,714; 5,015,324; 5,150,130; 5,961,228; 4,640,191; and 4,541,340; and the Paxar Model 676 printer User Manual, all of which are incorporated herein by reference. Some of these methods and apparatuses lend themselves to use with large scale commercial printing equipment on which large sheets or webs of fabric are printed, and then cut or slit into strips for fabric labels. These labels are suitable for use in garments for the purpose of decoration, identification, advertising, wash and care instructions, size, price, as well as other purposes. 
     Product labels utilized in garments typically endure several hundred washings in their lifetime and a garment that is dry-cleaned might be required to endure dozens of cleanings in its lifetime. The abuse to which such labels are subjected during industrial washing and dry-cleaning causes fraying and eventually obliteration of conventionally printed labels; yet, printing of such labels is highly desirable because labels can be printed at much higher speeds than they can be woven. 
     Sublimation printing basically involves applying a sublimation dye onto a substrate, such as a surface of a fabric. To perfect the transfer of the dye to the fabric, the fabric is carried through a curing operation in which the fabric is heated to sublime the dye. In the past, the fabric was typically heated on only one side by feeding the fabric over, for example, an anvil or past a lamp. U.S. Pat. No. 4,541,340 illustrates another system that uses a Xenon flash lamp to heat a printed side of the web. One of the problems with these approaches was that the fabric was not evenly heated. 
     Another problem with prior art approaches to curing the sublimable dye was that the fabric temperature was not closely monitored or controlled so that, for example, at start up, the fabric would be fed through the curing station before it had an opportunity to reach the necessary sublimation temperature. It is not uncommon that the web stopped when the web jammed, an upstream printing operation stopped, or a downstream cutting and label stacking operation stopped. Moreover, if the web stopped, the web would be exposed to excessive temperatures that could damage the web. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the invention to provide an improved system and method for sublimating at least one sublimation dye on one or both sides of a web. 
     Another object of this invention provides a system for sublimating at least one sublimation dye on at least one side of a web, the system comprising a controller for controlling operation of a sublimation station, a heater coupled to the controller and spaced from the web for heating said web to a sublimation temperature to sublimate the at least one sublimation dye, at least one sensor for sensing a web temperature, and the controller energizing the heater in response to the web temperature to maintain the web temperature at substantially the sublimation temperature. 
     Still another object of this invention provides a sublimation station comprising a frame, a heater driveably mounted on the frame, the heater comprising a heating area for receiving a web having at least one sublimation dye; the heater being in spaced relation to the web and heating the web to a sublimation temperature to sublimate the at least one sublimation dye, a controller coupled to the heater for controlling operation of the heater, at least one sensor coupled to the controller for sensing a web temperature and generating a web temperature signal in response thereto, and the controller energizing the heater in response to the web temperature signal to maintain the web temperature at substantially the sublimation temperature. 
     Yet another object of this invention comprises printing system for printing a plurality of labels, the system comprising a printing station for applying at least one sublimable dye to at least one side of the web, a sublimation station situated downstream of the printing station, the sublimation station comprising a controller for controlling operation of the sublimation station, a heater coupled to the controller and spaced from the web for heating the web to a sublimation temperature to sublimate the at least one sublimable dye on the web, at least one sensor for sensing a web temperature, and the controller energizing the heater in response to the sensed web temperature to maintain the web temperature at substantially the sublimation temperature. 
     Still another object of this invention comprises a method for sublimating at least one sublimation dye on a web comprising the steps of moving a heater from a park position to an operating position at which the heater is in spaced relation to the web, sensing a web temperature, and feeding the web through the heater, and energizing the heater to heat the web to a desired sublimation temperature to sublimate the dye. 
     Yet another object of this invention comprises a method for printing labels comprising the steps of printing at least one sublimable dye on a web of material as the web moves through a printing station; the sublimable dye defining a plurality of label patterns, sublimating the at least one sublimable dye using a heater in spaced relation to the web of material, the heater being continuously energized to provide sufficient heat to sublimate the at least one sublimable dye, and cutting the web of material to provide a plurality of labels. 
     Still another object of this invention comprises a method for printing a plurality of labels comprising at least one sublimation dye, the method comprising the steps of printing at least one sublimation dye on at least one side of a web to define the plurality of labels, driving a heater into operative and spaced relationship with the web, sensing a web temperature with a first sensor and energizing the heater in response to the sensed web temperature in order to maintain the web temperature within a desired sublimation temperature range as the web is fed past the heater. 
     Yet another object of this invention comprises a printing system comprising a printer for printing at least one sublimation dye on a web as the web is fed through the printer, a sublimation station for subliming and diffusing the at least one sublimation dye on the web as it moves through the sublimation station, the sublimation station comprising a frame, a heater assembly driveably mounted on the frame and moveable between a park position and an operating position during which the heater assembly is spaced from the web and may heat the web; the heater assembly being energized continuously while in the operating position, a drive motor for driving the heater assembly between the park and operating positions, a sensor for sensing a temperature of the web as the web is being fed through the heater assembly and generating a sensed temperature signal in response thereto, a controller for controlling operation of the printer and the sublimation station, the controller energizing the drive motor to drive the heater assembly between the park position and the operating position and controlling the heater assembly to maintain the web within a sublimation temperature range in response to the sensed temperature as the web moves past the heater assembly. 
     These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a printing and sublimating system in accordance with one embodiment of the invention, showing a heater in a home or park position; 
     FIG. 2 is perspective view, similar to the view shown FIG. 1, showing the heater in an operating or extended position; 
     FIG. 3 is a fragmentary view showing various components of the internal components of the sublimation station; 
     FIG. 4 is an exploded perspective view showing various components of the heater; 
     FIG. 5 is a fragmentary view showing further details of the components shown in FIG. 3 with all heater covers removed; 
     FIG. 6 is a perspective phantom view illustrating various details of the sensors used in the sublimation station; 
     FIG. 7 is fragmentary plan view illustrating various details of the sensors and drive system; 
     FIG. 8 is a front view of the sublimation station illustrated in FIG. 3; 
     FIG. 9 is an exploded view illustrating the various components of the sensing system shown in FIG. 7; 
     FIG. 10 is an exploded perspective view showing details of a feed drive assembly; 
     FIG. 11 is a view showing the layout of the circuit illustrated in FIGS. 11A-11D; 
     FIGS. 11A-11D is a circuit diagram of a control system used in the embodiment being described; 
     FIGS. 12A-12D are flow charts of a process or routine for controlling the heater temperature and position; 
     FIG. 13 is another flow chart view illustrating a process or routine for controlling the heater temperature during operation of the sublimation station; 
     FIG. 14 is a fragmentary perspective view illustrating a plurality labels made in accordance with the system and methods described herein. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, there is shown a label manufacturing system  10  for printing on one or both sides, W 1  and W 2 , of a web W. The web W can be composed of fabric, such as is used to make garment labels and the like, or can be composed of paper, synthetic material, such as vinyl or plastic, or other materials. 
     The system  10  comprises a printer  12  for printing or applying at least one sublimable dye on one or both sides W 1  and W 2 ; a sublimation station  14  for causing at least one dye in the web W to sublime or vaporize and diffuse into the web W; and a stacker  16  for cutting and stacking a plurality of labels L (FIG. 14) after the web W has been printed, sublimed and cut by a cutter C. In the embodiment being described, the printer  12  may be a Paxar Model No. 636® printer available from Paxar Corporation of White Plains, N.Y., the assignee of this application. Further, the stacker  16  may be the Paxar SS Finisher, also available from Paxar Corporation of White Plains, N.Y. 
     The printer  12  comprises a control system or controller  12   a  that is coupled to both the sublimation station  14  and stacker  16 . In the embodiment being described, the controller  12   a  controls the operation of the entire system  10 , as will be described in detail later herein. In general, the printer controller  12   a  controls the system  10  to cause the web W to be drawn from the supply roll  18  and the printer  12  prints on one or both sides W 1  or W 2  with at least one sublimable dye determined by the color or colors desired to appear on the finished label. The web W is then fed through the sublimation station  14  which sublimates or vaporizes the at least one sublimable dye to fix it into the web W. Thereafter, the web W is cut by the cutter C (FIG. 14) into the plurality of labels L (FIG. 14) and stacked by the stacker  16 . 
     The sublimation station  14  comprises a housing  20  comprising a heating system or a heater  22  which can be driven from a rest or home position, illustrated in FIG. 1, to an extended or heating position, illustrated in FIGS. 2 and 3. The heating system or heater  22  comprises at least one first lamp  24  comprising a first pair of lamp bulbs  68  (FIG. 5) and at least one second lamp  26  comprising a second pair of bulbs  70 . In the embodiment being described, the first and second lamps  24  and  26  are opposed and face sides W 1  and W 2 , respectively, when the web W is being fed through heater  22 . 
     As best illustrated in FIG. 4, the first and second lamps  24  and  26  are substantially identical and comprise lamp covers  24   a  and  26   a , respectively. A sensor or thermostat  34  (FIG. 4) is mounted to cover  24   a  with screws  36 . The sensor  34  is coupled to a sublimation station  14  control circuit or controller  38  (FIGS. 3 and 11A) that controls the operation of the sublimation station  14 . In the embodiment being described, the sensor  34  (FIGS. 3 and 4) terminates power to the lamps  24  and  26  if the temperature within the housing  14  generated by the heater  22  exceeds normal operating temperature. 
     As shown in FIG. 4, a plurality of mount guards  40  are secured to covers  24   a  and  26   a  with screws  42  and washers  44  as shown. In the embodiment being described, the mount guards or mounting blocks  40  maintain the pairs of bulbs  68  and  70  (FIG. 5) spaced from covers  24   a  and  26   a . Terminal blocks  48  are mounted to a back panel  25  with screws  50 . In the embodiment being described, the covers  24   a  and  26   a  and back panel  25  are an integral one-piece construction formed of sheet metal. The terminal blocks  48  provide terminals for various electrical components mentioned later herein. In the embodiment being described, the lamps  24  and  26  of heater  22  provide sufficient energy to heat the web W to the temperature required to sublimate the dyes. 
     The heater  22  further comprises bulb covers  52  and  54  (FIG. 4) that are mounted to lamp covers  24   a  and  26   a , respectively, with screws  56  that pass through apertures  58  into mounting blocks  40 . 
     The lamp cover  24   a  comprises a sensor bracket  28  mounted to cover  24   a  with screw  30  that passes through washer  32 . The bracket  28  comprises a flag in the form of an aperture  28   a . The aperture  28   a  cooperates with a heater  22  position sensor  60  (FIGS. 2 and 3) that is mounted to a bracket  61  that is in turn mounted to an underside  14   a   1  of a top surface  14   a  of the housing  14 . In the embodiment being described, the sensor  60  senses the presence or absence of the aperture  28   a  and generates a signal indicating when the heater  22  is in or out of, respectively, the operating or heating position (illustrated in FIG.  2 ). 
     Referring back to FIG. 4, the lamps  24  and  26  comprise front panels or covers  24   b  and  26   b , respectively, that are mounted to the covers  24   a  and  26   a  with screws  62  as shown. A first pair of lamp bracket mounts  63   a  and  63   b  are mounted to cover  52  with screws  64  threadably received in brackets  63   a  and  63   b . A pair of second lamp bracket mounts  63   c  and  63   d  are mounted to cover  54  with screws  66  that are threadably received in mounts  63   c  and  63   d . In the embodiment being described, the lamp bracket mounts  63   a  and  63   b  cooperate to receive the lamps bulbs  68 , and the lamp bracket mounts  63   c  and  63   d  cooperate to receive the lamps bulbs  70 , respectively. Although the embodiment being described is shown with two pairs of lamp bulbs  68  and  70 , more or fewer bulbs may be used if desired. 
     The at least one first and second lamps  24  and  26  are coupled to a silicon controlled rectifier (SCR) controller  204  (FIGS.  3  and  11 B). A programmable pyrometer or controller  104  (FIG. 3) is connected to temperature controller  72  for controlling the actual temperature of the web W (FIG. 3) via its connection to SCR controller  204 . The control loop from lamps  24  and  26  to web W controls the actual temperature of the web W to permit dye sublimation to occur. If the web W temperature is below the desired temperature, the pyrometer  104  notifies the temperature controller  72  which in turn notifies the SCR controller  204  (FIG.  11 B). In response, the SCR controller  204  will increase the energy to the lamps  24  and  26  to increase the temperature of the heater  22 . If the web W temperature is too high the opposite occurs. Another programmable pyrometer  102  (FIG. 3) is connected to temperature controller  74  for the purpose of monitoring the temperature of the web W to stop the heater  22  if the temperature of the web W falls below a minimum required temperature. The sublimation temperature and the desired range at which the sublimation dyes on the web W will be sublimated will vary depending on such things as the type of labels being manufactured and the sublimation dyes being used. 
     During operation of the system  10 , the heater  22  and lamps  24  and  26  are moved substantially simultaneously in the direction of double-arrow A (FIG. 5) between the park position and the operating position. To effect this movement, the system  14  comprises heater drive system  23  that will now be described relative to FIGS. 5-9. The drive system  23  (FIG. 7) comprises a support bracket  76  that is mounted between walls  14   c  and  14   d  (FIGS. 6 and 7) with screws  85 . A pair of carriage shafts  78  and  79  (FIGS. 6,  7  and  9 ) are received in linear bearing mounts or blocks  80  and  81 . The bearing blocks  80  and  81  are mounted to and cover  26   a  (FIG. 4) with screws  83  that pass through washers  130  and apertures  26   a   1  of cover  26   a . The bearing blocks  80  and  81  further comprise a raised shoulder or projection  80   a  and  81   a , respectively. These projections are received in slots  100  (FIG. 1) of surface  14   c  of housing  14  to permit the mounts  80  and  81  to support the heater  22  and travel in the slots  100  between the park and operating positions mentioned earlier herein. 
     FIG. 7 is a top view of the drive assembly with the heater  22  removed from the bearing blocks  80  and  81  for ease of illustration. The bearing blocks  80  and  81  (FIGS. 7 and 9) are coupled to a drive motor  82  with a drive cable  86  and enable the heater  22  to be driven in the direction of double-arrow A in FIG.  5 . It should be understood that the drive motor  82  comprises a capstan  84  mounted on a drive shaft (not shown). As illustrated in FIG. 7, a plurality of pulley wheels  88  are mounted on the bracket  76  as shown. A pulley wheel  90  is mounted on a bracket  92  (FIG. 5) that has an end  92   a  mounted to a front panel  14   b  (FIGS. 1 and 7) of housing  20  with screws  94 . As best illustrated in FIG. 7, the ends  86   a  and  86   b  of cable  86  are fastened to at least one of the respective bearing mounts  80  as shown. 
     The system  14  comprises a spring  96  (FIG.  6 ), which resiliently biases the bearing blocks  80  and  81  and, consequently, heater  22  in the park or retracted position (illustrated in FIG.  1 ), such as when power to the drive motor  82  is terminated. During operation, the heater drive motor  82  is energized to wind the drive cable  86  on capstan  84  which in turn causes the bearing blocks  80  and  81  to move away from bracket  76  (as viewed in FIG. 7) until the heater  22  is in the extended or heating position shown in FIGS. 2 and 3. The heater  22  defines a generally elongate receiving area or slot  98  (FIGS. 1,  2 ,  3  and  8 ), which receives the web W when the heater  22  is in the heating position illustrated in FIG.  2 . As best illustrated in the view shown in FIG. 8, the web W is tensioned in the manner described later so that it is situated substantially equidistant between the pairs of bulbs  68  and  70  as illustrated. This facilitates heating both sides W 1  and W 2  of the web W substantially evenly. 
     FIG. 9 illustrates further details of the drive assembly for driving the heater  22 . Bushings  116  are received on shafts  78  and  79  and positioned between bearing blocks  80  and  81  and bracket  76 . Pulley wheel  88  is secured to bracket  76  with a cap screw  118  which secures a pulley shaft  122  having a bushing  124  and the pulley wheel  88  mounted thereon. A snap ring  126  secures the pulley wheel  88  to the pulley shaft  122 . 
     In the embodiment being described, the system  10  comprises a sensing system or means for controlling the output of the lamps  24  and  26  and, consequently, the web W temperature. In this regard, the system  10  comprises at least one first sensor  102  coupled to the controller  74  mentioned earlier and at least one second sensor  104  coupled to controller  72 , as shown in FIGS. 3-7 and  9 . The sensors  102  and  104  are secured to the brackets  106  and  108 , respectively, with screws  110  and  112  (FIG.  7 ), and brackets  106  and  108  are secured to the bearing blocks  80  and  81  with screws  113  and  115  as shown. The sensors  102  and  104  are aimed at the aperture  14   c   1  of surface  14   c  (FIGS. 1 and 2) and aperture  27  (FIG. 3) of lamp cover  26   a  to capture or sense the temperature of the heater  22  and web W as described later. 
     Referring to FIG. 9, bushings  117  are also situated on shaft  78  to separate the front wall  14   b  (FIG. 7) of housing  14  from the bearing mounts  80 . 
     FIGS. 3,  5  and  10  illustrate a feed assembly  138  for feeding web W through the station  14 . The feed or drive assembly  138  comprises a driven roll  140  situated between a first mounting plate  142  and a second mounting plate  144 . The driven roll  140  comprises a shaft  150  having a first end  150   a  and a second end  150   b  which are received in the bushings  146  and  148 , respectively. A bracket base plate  151  is mounted between the first and second brackets  142  and  144  and connected to the plate  151  with screws  153  are threadably received in threaded holes, such as holes  155  in the plate  151 . 
     The feed assembly  138  further comprises a roller  154  that cooperates with driven roll  140  to drive or feed web W through sublimation station  14 . The roller  154  comprises a first end shaft  154   a  and a second end shaft  154   b  that are rotatably received in a first aperture  156   a  and a second aperture  158   a , respectively, of the L-shaped members  156  and  158 . The L-shaped members  156  and  158  each comprise a bolt  160  that receives a washer  162  and springs  164  that secures the L-shaped members  156  and  158  to the brackets  142  and  144 , respectively. The springs  164  comprise a bent end  164   a  received in aperture  156   b  in arm  156  and an end  164   b  that engages screw  159 . The springs  164  resiliently bias the roll  154  against the driven roll  140 , as shown in phantom in FIG.  8 . 
     As illustrated in FIG. 3, the feed assembly  138  comprises a jam sensor  168 , which senses the presence or absence of the web W, as well as if the web W is jammed. As will be described in detail later herein, if the web W is not present, the sensor  168  generates a signal ultimately received by the printer controller  12   a  so that the sublimation system  14  will not start, or if it has previously started, the system  10  will respond by retracting the heater  22  to the park position shown in FIG.  1 . Also, if the web W should break during operation, the sensor  168  will sense this condition and also cause the heater  22  to be retracted. The process of operating the sensors  34 ,  60 ,  102 , 104 ,  108  and  168  will be described in more detail later herein relative to FIGS. 11A-11D. 
     In a manner conventionally known, the feed assembly  138  further comprises a feed motor  170  (FIGS. 3 and 10) that is operatively coupled by at least one belt and pulley (not shown) to the driven roll  140  to drive the roll  140  to feed the web W from the printer  12 , through the sublimation station  14 , and to a subsequent operation, such as a cutting and stacking operation. 
     As best illustrated in FIGS. 3 and 5, the system  14  comprises an air filter assembly  171  comprising a pair of vent hoses  174  and  175  that open to a pair of brackets  178  and  180 , respectively. A pair of exhaust fans  182  and  184  exhaust air from the elongate area  98  (FIG. 3) through at least one filter  186  and  188 , respectively. A pair of filter caps or shrouds  190  and  192  comprise a plurality of detents  190   a  and  192   a  for securing the at least one filters  186  and  188  to the exhaust fans  182  and  184  as shown. The filter shrouds  190  and  192  are removably secured to the exhaust fans  182  and  184  to permit removal or replacement of the filters  186  and  188 , respectively, as needed. The exhaust fans  182  and  184  are vented through a pair of apertures (not shown) on a back wall  14   d  (FIGS. 1 and 3) of system  14 . 
     The system  14  controller  38  and its operation with printer controller  12   a  will now be described relative to FIGS. 11-11D. The controller/control circuit  38  comprises a conventional AC entry terminal  220  which is coupled to a circuit breaker  202  which in turn is coupled to the SCR controller  204  via conventional terminal blocks  206 . The SCR controller  204  is coupled to bulbs  68  and  70  through terminal blocks  48  and the thermostat  34  mentioned earlier herein. The terminal blocks  206  are further coupled to a power supply  210  which provides as its output a 24-volt DC voltage for powering various components, such as the fans  182  and  184 . 
     The relay  212  is also coupled to a seven-pin conventional microplug  214  which is coupled to stacker  16  as shown. The feed motor  170  is powered off lines  216  and  218  and is controlled by a rheostat  220  for controlling and setting the speed at which the motor  170  drives the web W through the sublimation station  14 . 
     Controller  204  comprises a pair of input terminals  204   a  and  204   b  that receive input from controller  72  which in turn is coupled to sensor  104 . In the manner described later herein, the controller  72  provides control input to controller  204  for controlling the power provided to lamps  68  and  70  during normal sublimation operation. Likewise, the sensor  102  is coupled to solid state relay  226  through controller  74 . In the embodiment being described, sensor  102  detects the temperature of the web W when the heater  22  is in the heating or operating position (FIGS. 2 and 3) and a temperature of the heater  22  when the heater  22  is in the park position (FIG.  1 ). Both sensors  102  and  104  are infrared sensors that sense infrared radiation through aperture  14   c   1  (FIGS.  1  and  2 ). If the web temperature sensed by sensor  102  is at a desired set point or within the desired sublimation temperature range, using the controller  74 , then the web W is continued to be fed through the station  14 . If, however, the temperature of the web W is not within the desired temperature range for sublimating the at least one sublimation die on the web W, then controller  72  transmits a signal via lines  222  and  224  to a normally closed solid state relay  226 . The relay  226  opens the normally closed gate  227  to generate an “OUT-OF-RANGE” signal on line  228  that is received by printer controller  12   a  via stacker  16 . The sublimation station  14  includes the seven-pin receptacle  230  which is coupled to stacker  16 . The line  228  is coupled to the line (not shown) of stacker  16  so that when relay  226  provides the “OUT-OF-RANGE” signal on line  228 , the printer  12  receives the signal and responds in the same manner as when a “STACKER FULL” signal is received. Namely, the printer  12  immediately terminates power to the web feed motor  82  and motor  170 . This causes the web W to stop moving through the printer  12 . With power to motor  82  terminated, the spring  96  (FIG. 7) retracts the heater  22  to the home position shown in FIG.  1 . It should be appreciated that the sublimation station  14  is attached and controlled by the printer controller  12   a . The printer controller  12   a  has a standard peripheral interface  240  and is capable of supplying approximately 1.5 amps of current on line  241 . The “OUT-OF-RANGE” signal is an input from control circuit  38  to printer controller  12   a  and functions similar to a conventional “STACKER FULL” signal. When the printer controller  12   a  receives this signal, the printer  12  will stop printing if it is already printing or will ignore operator requests to start printing if the printer  12  is idle. The printer  12  will generate and display an error message as long as the signal is asserted on line  228 . This line  228  is pulled up to a logic high within the printer  12  and any peripheral attached to the printer  12  can assert an error condition or notice by pulling this line  228  down to a logic low. This allows multiple peripherals such as the sublimation station  14  and the stacker  16 , to be attached to and signal the printer controller  12   a  by asserting or using this line  228 . In the embodiment being described, the line  228  is connected to printer  12  via receptacle  230 . 
     The printer controller  12   a  is coupled to the heater  22  drive motor  82  via a bipolar stepper motor drive channel  46 . The circuit  38  further comprises a sensor channel comprising a standard optocoupler interface  250 . The printer  12  comprises a pair of resistors, labeled R 1  and R 2  in FIG. 11C, which are coupled to lines  241  and  243 , as shown. Line  241  is also connected to an analog-to-digital converter  252  for converting analog signal on line  241  to a digital signal for use by the printer controller  12   a.    
     Circuit  38  comprises a resistor R 3  that is coupled to a phototransistor  254 . A light emitting diode (LED)  256  is situated in opposed relation to the transistor  254  to provide the sensor  60  (FIG.  3 ). Similarly, the sensor  168  (FIG. 11D) comprises the phototransistor  258  and opposed LED  260 . The LED  260  is coupled to a fourth resistor R 4  (FIG. 11D) which is coupled to a fifth resistor R 5  and a sixth resistor R 6  and a power supply  210  as shown. The circuit  38  further comprises a resistor R 7  and capacitor C 1  which are coupled in series and connected to line  245 . In the embodiment being described, the printer controller  12   a  may determine the type of sublimation system to which it is coupled by applying a current on line  262  and monitor the change in the voltage state to determine whether the sublimation station  14  which is coupled to the printer  12  is of the type shown and described herein or of a predecessor model, such as Paxar Model No. 636® Lokprint, available from Paxar Corporation of White Plains, N.Y. 
     An electronically erasable programmable read only memory (EEPROM)  262  is also coupled to line  245 , but is non-functional in the embodiment being described. Also, a plurality of fuses F 1 , F 2  and F 3  may be provided to protect the controller  38  from overload. The operation of the controller  38  and printer controller  12   a  will now be described. 
     In general, the sensors  102  and  104  monitor the temperature of the web W or the temperature of the heater  22 . Sensor  104  operates independent of the sensor  102 , which monitors the temperature of the web W at start up and the temperature of the heater  22  when the heater is in the home or park position. For example, when printer  12  is applying at least one sublimation dye to at least one side W 1  or W 2  of web W as it is fed through printer  12 , the heater  22  is driven to the operating position illustrated in FIGS. 2 and 3. At any point when the printer  12  is stopped, the printer controller  12   a  terminates power to motor  82 , whereupon spring  96  causes the heater  22  to retract to the home position (FIG.  1 ). This facilitates preventing the heater  22  from overheating or burning the web W. 
     While in the rest position, the sensor  102  senses the temperature of the heater  22  to determine if the heater  22  temperature is at the desired temperature set in controller  72 . The output of the sensor  102  is coupled via controller  74  and solid state relay  226  to line  229  of the connector  230  mentioned earlier herein. If the temperature sensed by sensor  102  is outside the desired range, then controller  72  causes the relay  226  to generate the “OUT-OF-RANGE” signal on line  22  that functions like a conventional “STACKER FULL” signal mentioned earlier herein. The printer controller  12   a  receives this signal and stops the printing operation and simultaneously terminates power to motor  170 . This causes the web W to cease moving through sublimation station  14 . Substantially simultaneously, the printer controller  12   a  ceases energizing stepper motor  82 , and spring  96  (FIGS. 6 and 7) causes the heater station  22  to retract to the home or park position illustrated in FIG.  1 . 
     As best illustrated in FIGS. 3 and 11B, the system  14  comprises a mechanical switch  280  which senses when the heater  22  is in the fully retracted position illustrated in FIG. 1 or in the extended position illustrated in FIG.  2 . The switch  280  is used to switch the temperature controller between two predetermined set points depending on the position of the heater  22 . If the heater  22  is in the park or home position illustrated in FIG. 1, then switch  280  is inactive and causes the SCR controller  204  to pass current to lamps  68  and  70  until they achieve a resting set point temperature. This enables the lamps  68  and  70  to remain energized while the heater  22  is in the rest or park position to avoid prolonged startup times when the printer  12  is first started. If, on the other hand, the heater  22  is in the operating position illustrated in FIGS. 2 and 3, then the switch  280  is activated or closed and SCR controller  204  provides more power to lamps  68  and  70  to increase the temperature output of the heater  22 . At startup the web W is not within the desired sublimation temperature range and needs to be brought up to within that range as quickly as possible. Thus, the switch  280  and SCR controller  204  cooperate to control the output of lamps  68  and  70  until the web W temperature reaches the set point temperature. 
     As best illustrated in FIGS. 11A-11D, the web sensor  168  comprises the photodiode  260  which cooperates with the phototransistor  258  to sense the presence or absence of the web W as it moves through the sublimation station  14 . When the web W is properly positioned between the photodiode  260  and phototransistor  258 , the web W will block the light from photodiode  260 , thereby indicating the presence of the web W. If the light from the photodiode  260  is received by phototransistor  258 , the phototransistor  258  is turned on, thereby indicating that the web W is not in its proper position. The output of the sensor  168  is combined with the output of sensor  60  which operates in a similar manner except that the sensor  60  utilizes the arm of sensor bracket  28  and the aperture  28   a  to sense when the heater  22  is in the operating position (FIGS.  2  and  3 ), in which case the aperture  28   a  permits the LED  256  to energize the phototransistor  254 . The bracket  28  blocks the LED  256  light when not in the operating position. 
     As mentioned, the output of the sensor  60  is combined with the output of the sensor  168  and this output is provided via line  241  (FIG. 11C) to the analog-to-digital converter  252  (FIG. 11C) which in turn provides three distinct states that are represented by three distinct voltage levels as follows: 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                   
                   
                 HEATER 
                 WEB W 
               
               
                 STATE 
                 VOLTAGE LEVEL 
                 22 POSITION 
                 PRESENT? 
               
               
                   
               
             
            
               
                 1 
                   &gt;4 VOLTS 
                 PARK 
                 EITHER 
               
               
                 2 
                 &gt;2.5 VOLTS, &lt;4 VOLTS 
                 OPERATING 
                 NO 
               
               
                 3 
                 &lt;2.5 VOLTS 
                 OPERATION 
                 YES 
               
               
                   
               
            
           
         
       
     
     The thermostat  34  (FIGS. 4 and 11B) is attached as described earlier herein and will interrupt the power provided by SCR controller  204  to the lamps  68  and  70  if the thermostats temperature rating is exceeded. In the embodiment being described, the thermostat  34  is selected to have a temperature rating higher than the operating end of the operating sublimation temperature range. 
     The process or sequence of operation of the printer  12  in combination with the sublimation station  14 , heater  22  and web W temperature control and a procedure for tightening web W will now be described relative to FIGS. 12A-13. 
     The web W is supplied from a supply roll  18  (FIG. 1) to printer  12  and an operator threads it to the nip  194  (FIG. 3) between rollers  140  and  154 . The operator may initially manually rotate the knob  155  (FIG. 3) to tension the web W. The operator powers the printer  12  and the sublimation station  14  at which time the web W is brought up to the sublimation temperature and the printer  12  may begin applying the at least one sublimation or sublimable dye is applied to either or both the first side W 1  or second side W 2  of the web W. The feed assembly  138  feeds the web through the nip  194  between driven roll  140  and roller  154 . As best illustrated in FIG. 8, it is desirable to provide enough tension on the web W so that the web is situated substantially equidistant from the lamps  68  and  70  as mentioned earlier herein. This facilitates ensuring that the web W does not sag, for example, towards the lamp  70 , which would cause side W 2  of web W to receive more radiant heat than desired and the side W 1  of web W to receive less radiant heat than desired. After the web W is properly tensioned by the operator using a conventional tension knob  155  (FIG.  3 ), the printer controller  12   a  performs a start-up sequence that will now be described relative to FIGS. 11-13. 
     After the operator loads the web W and the printer  12  and sublimation station  14  are powered on, the printer  12  and station  14  are in the idle state as indicated at Block  300  in FIG.  12 A. The routine proceeds to decision block  302  where sensor  102  senses the temperature of the heater  22  in the rest position. At decision block  304 , it is determined whether the temperature has achieved the park or home temperature set point programmed by the user into controller  72 . If it has not, the printer controller  12   a  indicates an error on a printer user interface (not shown) at block  306  and thereafter loops back to the printer idle state at block  300 . 
     If the decision at a decision block  304  is yes, then any previous error indicator is turned off at block  308 . If the operator has not requested to start printing, then the routine loops back to the printer idle state at block  300  as shown. After an operator requests to start printing, the routine proceeds to reset a first step counter (not shown) in printer controller  12   a  and a second step counter (not shown) in printer controller  12   a  at block  312 . The routine proceeds to block  314  where a temperature timer and web drive timer in printer controller  12   a  are also reset. 
     Before the printing process begins, a web tightening process may be initiated and a web drive timer (block  317  in FIG. 12B) is started. Next, it is determined whether the web drive timer has exceeded two seconds at decision block  318 . If it has not, then the routine loops back as shown. If the web drive timer has met or exceeded two seconds, thereby indicating that the web drive motor  170  has been energized for at least two seconds, then the web W is properly tensioned and the routine proceeds to block  319  where the drive motor  170  is de-energized. 
     Thereafter, the routine proceeds to block  320  where the printer controller  12   a  begins energizing the stepper motor  82  (FIGS. 7, and  11 ) to move the heater  22  toward the operating position illustrated in FIGS. 2 and 3. At block  322 , the first step counter is incremented and the routine determines at decision block  324  whether the counter has exceeded a maximum count, which corresponds to an error condition, such as, if the heater  22  feed motor  82  is jammed. If it has not, then it is determined whether the heater  22  is in the proper position at decision block  326  and if it is not then the routine loops backs to block  320  as shown. If the decision at block  324  is yes, thereby indicating that the count of the stepper motor has achieved a maximum count (corresponding to a count in excess of a step count needed to drive the heater  22  into the proper position), then the routine proceeds to turn the printer error indicator on at block  328 . Thereafter, the routine proceeds to block  330  and printer controller  12   a  removes power from the heater  22  drive motor  82  and the spring  96  (FIG. 7) returns the heater  22  to the rest or home position illustrated in FIG.  1 . The routine then returns to the printer idle condition at block  300  in FIG.  12 A. 
     If the decision at block  326  is affirmative (FIG.  12 B), meaning that the heater  22  is in the proper position for heating the web W, then the routine proceeds to block  332  and printer controller  12   a  energizes drive motor  82  to step the heater  22  toward the operating position shown in FIGS. 2 and 3. At block  334 , the second counter is incremented and the routine proceeds to determine whether the second counter equals ten, which corresponds to the number of counts necessary to get the sensor  60  centered in aperture  28   a . It should be appreciated that the step count may be higher or lower depending on the characteristics of the aperture  28   a  or stepper motor  82 . If the second counter is not equal to ten, then the heater  22  is not in the proper operating position to heat the web W, and the routine loops back to block  332  as shown. If the second counter does equal ten counts, then the aperture  28   a  (FIG. 3) of bracket  28  should be aligned in sensor  60  to permit the diode  256  (FIG. 11) to energize the phototransistor  254  and the sensor  60  should be relatively insensitive to vibration. 
     It is next determined by sensor  168  whether the web W is present and in the proper position at decision block  338 . If it is not, then the error indicator (block  342 ) on the printer  12  is energized. The printer controller  12   a  further terminates power to the stepper motor  82  (block  346 ) so that spring  96  (FIG. 7) can return the heater  22  to the home or park position (shown in FIG.  1 ). Thereafter, the routine loops back to the printer idle condition at block  300  (FIG.  12 A). 
     If the decision at block  338  (FIG. 12C) is affirmative, then the printer controller  12   a  starts the temperature timer TT (not shown) at block  340 . It should be appreciated that when the heater  22  is in the operating position illustrated in FIG. 2, the manual switch  280  (FIGS. 3 and 11B) is activated so that the SCR controller  204  (FIG. 11B) sets the temperature setting to the operating temperature set point. Thereafter, the routine proceeds to block  348  (FIG. 12D) where sensor  102  senses a temperature of the web W within the area  98  of the heater  22 . At block  350 , it is determined whether the web W is at the proper temperature to sublimate the dye which has been printed on one or even both sides W 1  and W 2  of printer  12 . If it is not at the proper temperature, then it is determined (block  352 ) whether the temperature timer TT is greater than or equal to five seconds, which corresponds to the maximum time required for lamps  68  and  70  to bring the web W up to the proper sublimation temperature mentioned earlier herein. If the temperature timer TT has not achieved at least five seconds, then the routine loops back to block  350 . On the other hand, if the temperature timer TT has achieved at least five seconds while the web W is not at the proper temperature to sublimate the at least one sublimation dye, the routine proceeds to block  342  where an error indicator on the printer  12  is again initiated and stepper motor  82  is de-energized and spring  96  returns heater  22  to the home position. 
     If the decision at decision block  350  is affirmative, then the routine proceeds to block  354  where the printer  12  begins applying the at least one sublimation dye to at least one or both of the sides W 1  and W 2  of the web W. Thereafter, the web drive motor  170  (decision block  356 ) is energized to pull the web W through the printer  12  and sublimation station  14 . During this time, the sublimation station  14  continuously monitors the temperature of the web W using sensor  102  to ensure that the web W is at a proper temperature to sublimate the at least one sublimation dye. Thus, if it is determined at decision block  358  (FIG. 12D) that the web W is not at the proper temperature to sublimate the at least one sublimation dye, then the routine proceeds to indicate an error indicator or message on the printer  12  when it returns to block  342  (FIG. 12C) as shown. If the web W is at the proper sublimation temperature, the web W is present and in the proper position, and the heater  22  is in the print position (illustrated in FIGS.  2  and  3 ), then printing is performed. The web W is passed to the stacker  16  where web W is cut by cutter C (FIG. 14) to provide the plurality of labels L. It is then determined whether printing is complete (decision block  356 ). If it is not, the routine continues to monitor the web temperature and returns to decision block  358 . If the printing is complete, then the routine returns to block  344  (FIG. 12C) where the web drive motor  170  is de-energized and power from the heater drive motor  82  is terminated (block  346 ). As mentioned earlier, this enables spring  96  (FIG. 7) to return heater  22  to the park position. If the web W is at the proper temperature to sublimate the at least one sublimation dye as determined at decision block  358 , but the web W is not present or in the proper position in the heater  22  or the heater  22  is not in the print position, then the routine again generates an error indicator or message and returns to block  342  (FIG.  12 C). 
     The process of controlling the web W temperature will now be described relative to FIG. 13 wherein it is determined at decision block  364  whether heater  22  is in the park position illustrated in FIG.  1 . If it is not, then SCR controller  204  (FIG. 11D) sets the temperature set point for the desired operating or web temperature (block  362 ) using controller  74 . If the decision at decision block  364  is affirmative, then the SCR controller  204  sets a heater  22  temperature set point for a desired heater  22  temperature (block  368 ). As mentioned earlier, the heater  22  temperature is the operating temperature of the lamps  68  and  70  while in the park position. 
     At block  370 , the sensor  104  senses the temperature of the web W and controller  72  (FIG. 11A) determines (block  372 ) in FIG. 13 whether the temperature exceeds the desired set point temperature. If it does not, then SCR controller  204  increases the lamp intensity (block  374 ). If the web temperature equals or exceeds the desired set point temperature, then the controller  204  (FIG. 11B) decreases power to the lamps  68  and  70  to lower the lamp intensity (block  376 ). After increasing or decreasing the lamp intensity at blocks  374  and  376  the routine loops back to decision block  364  as shown. 
     Advantageously, this system and method provides means for controlling the position of the heater  22  and the temperature generated by the heater  22  so that a web temperature of the web W will be maintained at substantially the desired sublimation temperature or within a desired sublimation temperature range. This system and method further facilitate bringing the web temperature up to the desired sublimation temperature or within the sublimation temperature range before the web W moves through the sublimation station  14 . 
     Moreover, it has been found that as the web W moves from a printer end  22   e  to the stacker end  22   f , the sublimable dye will be sublimated approximately midway through the heater  22 . It has been found that the additional time that the web W is exposed to the lamps  68  and  70  of heater  22  as the web W travels from midway through the lamps to the end  22   f  facilitates ensuring that the at least one sublimable dye that is printed on one or both sides of web W has been properly sublimated. 
     While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention, which is defined in the appended claims.