JPS648062A - Printer - Google Patents

Abstract

PURPOSE:To prevent overenergization of a thermal head and improve printing quality by calculating the actual number of printing dots in a line to be printed, accumulating the actual number of printing dots in a preceding line, and controlling energization time for a heat generating element based on the accumulated number of printing dots. CONSTITUTION:The density of a thermal head 6 is obtained by starting, and a printing period from the start of printing the first line to the start of printing the second line, is sought. Next, the actual number of printing dots in a single line is counted by a counter 8 to obtain the degree of impact by a printing period and the actual number of printing dots, and then the obtained degree as an accumulated numbers is stored in RAM 3 and a correction value for energization time is sought based on the accumulated numbers and temperature. After this, the correction value is subtracted from a basic energization time to obtain an optimum energization time. Furthermore, a whether a thermal head is energized on not when each dot to a preceding line is printed is determined. If energized, the thermal head is to be energized by corrected energization time, and if not, it is to be energized by adding an adjusted energization time to the corrected energization time. This processing is to be performed by every line, and the energization time is to be reduced with the controlling of temperature rise to prevent overenergization of the thermal head.