| 摘要 |
<p>METHOD AND APPARATUS FOR TEMPERATURE CONTROL IN THERMAL PRINTERS of the Invention A thermal printing apparatus for printing on a thermal print medium (10) having a conversion temperature (TC) to which the thermal print medium must be raised to cause printing to occur. The apparatus comprises a thermal print element (40) and exposure means for providing energy to the print element at a first average rate for a time sufficient to raise the temperature of the print element from below the conversion temperature to a temperature above the conversion temperature, and for then providing energy to the print element at a second average rate, the second average rate being less than the first average rate but sufficient to maintain the temperature of the print element above the conversion temperature. The exposure means comprises print enable means (100) for generating an enable signal defining the total length of the energizing interval, modulation means (102) responsive to the enable signal for generating a strobe signal comprising a first pulse (84) followed by a series of second pulses (86), and driver means (50) for energizing the print element in response to the strobe signal pulses. The first pulse has a first pulse length sufficient to raise the temperature of the print element above the conversion temperature. Each second pulse has a second pulse length less than the first pulse length, and the series of second pulses have a duty cycle selected to maintain the temperature of the print element above the conversion temperature.</p> |
