| 摘要 |
<p>PURPOSE:To accelerate the heat responding speed of a heat printing head and to print at high speed by combining the switching of a voltage to be applied to a heat generating resistor and the driving of a chopper, thereby controlling the current flow of the resistor. CONSTITUTION:A pulse P0 to be applied from an input terminal 6a is input to a one-shot circuit 21 through an OR gate 20 of an applying voltage switching circuit 18. The circuit 21 outputs a single pulse having a predetermined width in response to the timing of a rising edge of the pulse P0. Since a first switching transistor 22 is conducted by the pulse and a second switching transistor 23 is thereby turned ON, a high voltage V1 applied to one high voltage input terminal 14 is applied to heat generating resistors 2a-2n during the pulse outputting period of the circuit 21. When a driver 4a is driven by a chopper driving pulse P1, a current flows to the corresponding resistor 2a, and the resistor 2a is abruptly heated at the time of the rise of starting the current flow.</p> |
