| 摘要 |
PURPOSE:To make constant a reducing ratio of applied energy, by providing a specified resistance circuit part, a discharging circuit part and switching circuits, using one of the swithcing circuits for setting a basic energization time for a heat generating element, and using the other switching circuits for setting a reduction in energization time. CONSTITUTION:A resistance circuit 10 is a resistor circuit part provided in common for charging circuit parts constituted of CR circuits 11-13 having different time constants, and is constituted of a resistor 1, a thermistor 2 and a variable resistor 3. Switching transistors 31-33 are connected to respective capacitors to constitute switching circuits for outputting pulse waveforms representing charging times required for charging the capacitors to predetermined charged levels. Discharging transistors 21-23 are provided in a discharging circuit part for simultaneously discharging the capacitors C1-C3 in the CR circuits. Wave-shaping buffers 34-36 are connected respectively to the switching transistors, and a trigger input terminal 17 instantaneously discharge the plurality of the capacitors. With this construction, the ratios of the pulse widths of output waveforms 43, 44 to that of an output waveform 42 are substantially constant over the entire temperature range. |
