POWER UNIT FOR PRINTER AND PRINTER THEREWITH

摘要

PURPOSE: A power unit for a printer is provided to minimize switching loss during control by optimizing the waveform of gate signals and to expand output control width by adopting a low-cost IGBT(Insulated Gate Bipolar Transistor) as a switching control element. CONSTITUTION: A voltage resonance converter has an IGBT(201) connected to a power source; a first resonant capacitor(204) connected to the IGBT in series; an IGBT(202) connected to the first resonant capacitor in series; an exciting coil(18) connected between the node of the first resonant capacitor and the first IGBT, and the power source; a second resonant capacitor(205) connected to the IGBT(202) in parallel; and regenerative diodes(206,207) connected in parallel respectively to the IGBTs. A gate control signal of each IGBT generates a switching timing signal from transfer voltage of an insulated type driving transformer while shaping the waveform.