Patent ID: 8098267

Claim:
A thermal printer apparatus comprising: a line thermal head for printing in a line sequential manner for each line in response to an energizing pulse corresponding to dot data containing information indicating whether or not there is a dot to be printed correspondingly to a print position; a driving circuit for supplying the energizing pulse selectively to the line thermal head in accordance with the dot data; a dot data memory for storing the dot data for each line in synchronization with line sequential printing and for delivering the dot data to the driving circuit; a first multiplier for counting a number of dots to be printed for each line, which is indicated by the dot data, and for multiplying a result of the counting by a first correction coefficient corresponding to a thermal conductivity characteristic of thermal paper; a heat accumulation counter for counting results of the multiplying the number of dots to be printed for each line, which is indicated by the dot data, by the first correction coefficient in an accumulative manner; a second multiplier for multiplying a count value in the heat accumulation counter by a second correction coefficient corresponding to the thermal conductivity characteristic of the thermal paper and a heat radiation coefficient repeatedly at a predetermined period, so as to correct and update the count value; and an arithmetic unit for calculating an energizing pulse width based on the corrected and updated count value in the heat accumulation counter in synchronization with the line sequential printing and for controlling the driving circuit based on a result of the calculating.