| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an induction heat fixing device able to exert PWM control by tracking resonance frequency without taking variation in component constant and a temperature change into consideration. <P>SOLUTION: The induction heat fixing device comprises: a series resonance circuit having an induction coil and a capacitor; a phase comparison part; a resonance frequency tracking oscillation part; and a PWM signal generating part. The phase comparison part compares the phase of a pulse output from the PWM signal generating part and the phase of a current flowing in the induction coil. The result of the comparison is output to the resonance frequency tracking oscillation part. Using output from the phase comparison part, the resonance frequency tracking oscillation part changes a resonance frequency so that the drive frequency of the series resonance circuit tracks the resonance frequency. Based on an oscillation frequency generated by the resonance frequency tracking oscillation part, the PWM signal generating part generates a pulse for driving the series resonance circuit. The phase comparison part, resonance frequency tracking oscillation part, and the PWM signal generating part are digitally controlled. <P>COPYRIGHT: (C)2012,JPO&INPIT |
