Patent ID: 6377290
Filing Date: 2002-04-23
Classification: B41J

Abstract:
In a thermal printer apparatus having a plurality of heating elements arranged in a thermal head, in which an energizing pulse is applied to the respective heating elements in accordance with a printing signal to energize the heating elements to perform a printing operation by printing on a print paper, the thermal printer apparatus comprising:temperature measuring means for measuring a temperature of the thermal head; voltage measuring means for measuring a voltage applied to the thermal head; and head drive means for calculating a maximum energizing pulse width T based upon the measured temperature of the thermal head and the measured voltage applied thereto, for calculating a main pulse width TM based on the maximum energizing pulse width T and a printing speed W, for calculating a sub-pulse width TS as a preselected ratio of the maximum energizing pulse width TM, and for outputting to the thermal head for the printing of one dot on a current line an energizing pulse for driving the thermal head, the energizing pulse having a pulse width selected as the smaller one of a summed pulse width of each of an energizing pulse having the calculated sub-pulse width and comprising an energizing pulse corresponding to print dot data for the current line prepared from a logical multiplication of inverted print dot data of a preceding line, and an energizing pulse having the calculated main pulse width TM and comprising an energizing pulse corresponding to print dot data of the current line and, the pulse width of the maximum energizing pulse T.