| 摘要 |
<p>PURPOSE:To accurately control density at a high speed, by performing printing while imparting a plurality of printing pulses during the printing period to one black pixel. CONSTITUTION:A reference clock is given to a printing pulse control circuit 10 to be gated and applied to the latch circuit 7 of a heat generating head unit 5 through a member line 8. The printing data arriving from an input termi nal 2 is given to a new data register 3 and a shift register 4 and also given to the printing pulse control circuit 10 to determine the number of printing pulses to send said pulses to the member line 8. The printing data of the present line stored in the shift register 4 is given to the latch circuit 7 and a current flows for a predetermined period corresponding to a black pixel through heat generating resistor elements 91-9640. By this method, the heat generating resistor elements 91-9640 of a thermal head corresponding to the black pixel generate heat to perform driving. As a result, a cooling time becomes short corresponding to the dividing number of printing pulses and, even when high speed printing is performed, the accumulation of heat is hardly generated in the thermal head.</p> |
