Patent ID: 8213823

Claim:
A power supply device including a piezoelectric element, a switching element configured to drive the piezoelectric element, and an oscillation unit configured to output a frequency signal to the switching element, configured to output a high voltage by driving the piezoelectric element at a frequency based on the frequency signal, the power supply device comprising: a control unit configured to output a control signal to the oscillation unit for controlling the oscillation unit to output the frequency signal; and a setting unit configured to set a switching-on time period of the switching element driven by the frequency signal, wherein the setting unit is configured to, in a frequency range from an initial frequency at which drive of the piezoelectric element is started to a driving frequency at which a target voltage is output from the piezoelectric element, set the switching-on time period in a frequency range including an interval during which a spurious resonance frequency is generated from the initial frequency, shorter than the switching-on time period when the piezoelectric element is driven at the driving frequency.