| 摘要 |
PURPOSE:To stabilize the temperature of a circuit element, by flowing a current I0 during a standby period to a semiconductor laser or a light emitting diode array, and flowing the current I0 or a current I1 during a picture recording period in correspondence with a picture signal, under the conditions of I0<Ith<I1. CONSTITUTION:Regardless of the printing period or the standby period of a laser beam printer (LBP), a temperature regulating circuit 9 turns ON/OFF a heater 7, and the temperature of a laser chip 2 is regulated at a constant value. During the standby period, a current I0 flows to the laser chip 2. During the printing period, the current I0 or a current I1 flows to the laser chip 2 in correspondence with a picture input signal. In this way, a laser driver circuit 10 is constituted. The current is made to flow under the condition of I0<Ith<I1, with respect to a threshold current Ith of the laser. Therefore the laser does not emit light during the standby period. During the printing period, the light is emitted in correspondence with the picture input signal. Namely, the ON/OFF control of the light emission of the laser is performed by a controller 11. |
