Patent attributes
A thermal head printer includes a platen, a thermal head having a heating element, a heating-value arithmetic unit, a heating-value comparator, an excess-value counter, and a heating-value controller. The thermal head printer performs a printing operation by conveying a recording medium between the platen and the thermal head and heating the heating element on the basis of image data to be printed. The heating-value arithmetic unit calculates heating values for the heating element corresponding to the image data. The heating-value comparator compares each calculated heating value with a reference heating value of the heating element. The excess-value counter counts the number of calculated heating values that exceed the reference heating value so as to determine an excess-value number. The heating-value controller limits the heating values of the heating element if the excess-value number exceeds a reference number.