PURPOSE: To hold printing density constant and to shorten a printing time by increasing the feed velocity of a printing head and a form when the temperature of the printing head and/or the form is a temperature where the printing density is higher than a prescribed printing density.
CONSTITUTION: While a feed motor 8 moves a thermal head 1 in the direction of a printing line at a normal feed velocity instructed by a feed velocity control part 7 by the instruction of a CPU 3, the thermal head 1 is actuated so as to perform printing at normal density on a form by the instruction of a thermal head printing control part 4. The temperature of the thermal head 1 is measured at time intervals and the CPU 3 compares the actual velocity instructed by the feed velocity control part 7 with a read target velocity. Then when the target velocity is higher than the actual velocity, the feed velocity control part 7 increases the feed velocity of the head 1 by the carrier motor 8. Reversely, when the target velocity is lower than the actual velocity, the feed velocity of the head 1 is low. Thereby the printing density is kept constant and the printing time is shortened.
MAEJIMA MIKIO
NAGAYA YOSHIAKI
HITACHI ASAHI ELECTRON KK