| 摘要 |
PURPOSE:To stabilize a laser output by eliminating influences of fluctuations of polarizing characteristics of the laser output by detecting the intensity of a laser beam not in a laser beam recording period and by controlling the output of the laser beam in the recording period by the detection output. CONSTITUTION:A laser output from a laser oscillator 1 is focused through a deflector 3 and an optical condensation system 4 to scan the surface of a photoreceptor 5, thus recording a picture. At the opposite side to the emission direction of the laser output from the oscillator 1, a photodetector 6 is arranged to detect the intensity of the laser beam in any period other than the recording period. Its detection signal is held by a sample holding circuit 8 with the signal of a synchronous control circuit 10, and on the basis of the held signal, a current value when a modulator 11 turns on the oscillator 1 is determined by a current control circuit 9. Then, a synchronizing signal from a synchronous oscillator 13 is applied to the circuit 10 and deflector 3 to control the output of the laser beam in the recording period according to the intensity of the laser beam detected by the photodetector 6, thereby stabilizing the output. |
