Power source device and image forming apparatus

An image forming apparatus forming an image, the image forming apparatus comprising a power source device,

• the power source device including:
• an oscillator generating a clock;
• a frequency division unit dividing the clock to output a pulse;
• a sequence generation unit generating an “N” number of sequences, in which each element has substantially the same occurrence rate, with respect to each switching of the pulse by synchronizing with the pulse;
• a frequency division ratio setting unit setting a frequency division ratio of the pulse;
• a switching element driven by the pulse;
• and
• a piezoelectric transformer outputting an alternating current high voltage from a secondary side thereof when a primary side thereof is intermittently applied with a voltage by the switching element,
• wherein the generated sequence and the set frequency division ratio are compared to output the pulse of a fractional-M frequency and the pulse of a fractional-M+1 frequency
• wherein an average frequency division ratio of the pulse of the fractional-M frequency and the pulse of the fractional-M+1 frequency is determined by (M×α)+(M+1)×β/(α+β), where the α represents the number of the pulses of the fractional-M frequency and the β represents the number of the pulses of the fractional-M+1 frequency per unit time, and
• wherein the average frequency division ratio and the frequency division ratio become substantially equal to each other at a sequence generation cycle, and become approximated to each other in a period shorter than the sequence generation cycle.