| 摘要 |
PURPOSE:To equalize the density of printing by setting the input of a pulse width control circuit to predetermined voltage and slowly bringing the voltage close to the voltage of a power supply at a moment when a heating element is conducted first after a state that the element is not conducted for a fixed period is continued. CONSTITUTION:When the heating element 2 is conducted first after conduction to the element is suspended for some period, a transistor 56 is turned ON at a moment when conduction is started, the charging voltage of a capacitor 54 is lowered instantaneously up to Vl=VR1/(R1+RS), and the transistor 56 is turned OFF. The charging voltage of the capacitor 54 rises in exponential function form at time constants RiCi 53, 54 toward V from Vl. Since the element is conducted in the process of the rise, pulse width is made wider than conduction pulse width in case of the application of voltage V, and the reaching temperature of the heating element 2 at that time is elevated, and can exceed a reference temperature. |
