| 摘要 |
PURPOSE:To make constant a reducing ratio of applied energy and obtain favorable printing quality, by performing comparison of a charged level of a capacitor with a reference voltage at different charged levels, converting comparison outputs into pulse widths, using one of the resultant outputs for setting a basic energization time for heat generating elements, and using the other for setting a reduction in the energization time. CONSTITUTION:When TRIG is inputted through a TRIGIN terminal, a transistor 4 is momentarily turned ON, and then charging of a capacitor 5 from a power source Vc through a resistor 2, a heat-sensitive resistor element 3 and a variable resistor 1 is started. When the charged level of the capacitor 5 reaches a reference voltage VREF2 in a second voltage-comparing circuit 7, the output of the voltage-comparing circuit 7 is inverted, and a pulse width t2 is obtained. Thereafter, when the charged level of the capacitor 5 is raised to reach a reference voltage VREF1 in a first voltage-comparing circuit 6, the output of the circuit 6 is similarly inverted, and a pulse width t1 is set as a basic energization time for a dot. The pulse width t2 is set as a reduced energization width time for the next dot stored as a thermal hysteresis. A point J represents a charging terminal for the capacitor 5. |
