PURPOSE: To obtain a print having no irregularity by detecting the quantity of light from a xenon lamp and controlling it to a constant quantity at all times.
CONSTITUTION: An energy control circuit 23 compares information from a storage part 22 with the output of an integrator 21 and sends a light emission stop signal to a light emission stopping circuit 24 when they become equal in value to each other. The light emission stopping circuit 24 when receiving the light emission stop signal cuts off a current flowing to the xenon flash lamp 15 to stop light emission. Here, an applied voltage is held constant to perform light emission on the best conditions at all times, and the light emission time is controlled to control light emission energy. Consequently, the light emission is performed with good efficiency at all times and the power consumption is reducible. Further, the xenon flash lamp varies in the quantity of light emission with the lamp temperature and with, so the quantity of light emission is detected directly to control the energy, thereby taking an invariable stable copy.