| 摘要 |
PURPOSE:To obtain an uniform record density, by judging the tone level of a record signal and accumulating predetermined thermal storage index corresponding to the tone level, thereafter controlling a pulse signal such that the record density for same gradation is made constant based on the record signal and the accumulated thermal storage index. CONSTITUTION:A tone level signal is fed through an input terminal 1 and a judging circuit 2 judges the tone level of the tone level signal and provides a corresponding thermal storage index to a first selector 3. The first selector 3 sequentially selects the tone level signal judging circuit 2 and one counter in a thermal storage index counter circuit 4 and connects them each other. Thermal storage index is stored through each counter for every heating resistor during an interval from start of record to a record line, while a second selector 5 sequentially selects one counter in the counter circuit 4 and a pulse generator 6 and connects them. A pulse signal is generated based on the tone level of the tone level signal and the accumulated thermal storage index then the pulse is applied onto the thermal head 7. Number of pulse in the pulse signal is corrected in the paper feed direction thus optimizing the amount of heat to be produced from each heating resistor. |
