| 摘要 |
<p>PURPOSE:To enable the density distribution in a dot to be uniform, by supplying a first energizing pulse to rapidly raise the surface temperature of a resistance heat generating element, and supplying second energizing pulses consisting of a plurality of pulses having a small pulse width. CONSTITUTION:With a printing timing pulse given in synchronism with a recording paper feeding operation, a first pulse generating circuit 2 generates a first energizing pulse P1 with a pulse width tau1, whereby the surface temperature of a resistance heat generating element is rapidly raised, reaching a predetermined temperature corresponding to a printed density after the lapse of time of tau1. When the generation of the first energizing pulse P1 is completed, ON- OFF pulses with a fixed pulse width tau3 are generated with a repetition period T3 determined by the printed density, and the output of a second energizing pulse P2 is repeatedly generated until a preset printing time tau0 elapses. since the heat generating temperature corresponding to the printed density which is obtained by the first energizing pulse P1 is thus maintained, the density distribution in a dot can be maintained to be uniform.</p> |
