| 摘要 |
PURPOSE:To decrease the fluctuation of a laser optical output by decreasing the temperature fluctuation of laser during print operation in the laser light source device of a laser beam printer. CONSTITUTION:The driving current of a semiconductor laser 1 is fed from a switching current source 10 and a bias current surce 8. Since the current capacity of the bias current source 8 is set to the threshold current value of below of the semiconductor laser 1, when a video signal is at L level and a transistor 9 is turned off, the optical output is decreased to the exposure level of a photosensitive drum 5. The bias current is set before the print start and when the semiconductor laser 1 is modulated after temperature equilibrium is reached, then the temperature is risen by the bias current, the temperature change is decreased and then the optical output fluctuation is also decreased. |
