| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the load on a power source battery and to prolong an operable time by varying the maximum number of simultaneously heated dots to a number matching the rest capacity of the power source battery when the battery rest of the power source battery decreases and its voltage drops. SOLUTION: For printing, the heating dots of a thermal head 5 are are heated and the power source voltage 18 has a voltage drop owing to a large current at this time. For the purpose, the voltage value of the power source battery 18 is converted from analog to digital by an analog-to-digital(A/D) conversion part 17 and compared by a central processing unit(CPU) 8 with the discharge characteristic curve that the power source battery uniquely has to specify the battery rest. The output voltage of the power source battery drops owing to continuous printing, but when this reaches its threshold value, the CPU 8 commands a decrease in the maximum number of simultaneously heated dots to carry on the printing process. Consequently, the output voltage rises. In this state, the printing is further carried on and when the voltage approximates the threshold value again, the maximum number of simultaneously heated dots is further decreased to perform the printing operation.</p> |
