THERMAL PRINTER AND PRINTING METHOD

摘要

PROBLEM TO BE SOLVED: To prevent print quality from deteriorating by providing means for monitoring the lifetime of a thermal head and changing the printing state when the end of lifetime approaches thereby notifying the lifetime state of the thermal head before dot miss occurs. SOLUTION: A head control circuit 9 receives values from the resistance rank recording means 81 and temperature measuring means 82 of a line thermal head 8 and stores a print data received by a volatile RAM 3 into a receiving buffer the print data is subjected to dot development in an edition buffer. Number of print lines X from the start of use of the head 8 is accumulated in a number of print line counter region provided in a nonvolatile RAM 4. Lifetime of the head 8 is monitored by comparing the X with a preset number of lifetime print lines of head Y. When a decision is made that X has reached Y, the conduction pulse width is set narrower and the print density is made thinner so that approach to the end of lifetime of the head 8 can be recognized.