THERMAL HEAD DRIVING DEVICE

PURPOSE:To improve quality of image to be outputted, by calculating a determined result of heat accumulation quantity of a thermal head and a correction factor and controlling power quantity for the thermal head. CONSTITUTION:A correction factor ROM 7 outputs correction factors corresponding to each dot in accordance with a correction data outputted from a correction line ROM 6. That is, when the number of printing line and the correction factor of each dot are obtained, a heat accumulation correction ROM 3 outputs power quantity corresponding to each printing line in accordance with gradation data of each dot and a reference temperature table. When the power quantity and heat accumulation correction factor of each dot at every line are outputted, a calculation of the power quantity and the correction factor of each dot is performed by a multiplier 9. Dependent on a correction power quantity to be outputted by the multiplier 9, energizing time is controlled an power supply to a thermal head 11 is controlled by a thermal head driving circuit 10.