Laser printer optical system.

摘要

A laser light source device is disclosed in which the intensity of laser light emitted from a laser diode (1) is detected, the detected value of the light intensity is compared with a predetermined value to generate a binary signal, the binary signal is used to controll the count mode of an up/down counter (17), and a current for driving the laser diode (1) is controlled on the basis of the output of the up/down counter, to prevent the intensity of laser light from decreasing.