Apparatus for controlling the intensity of a laser beam emitted from a semiconductor laser unit

摘要

In an apparatus for adjusting the intensity of a light beam, a first driving current which is stepwisely increased in a first cycle is supplied to a semiconductor laser. The light beam is deflected to scan a photosensitive drum and is detected to generate a positional signal by a photodetector outside of the drum. The intensity of the light beam is also detected by a monitor detector and compared with a predetermined target intensity. The comparison result is latched in a latch circuit to determine a first drive signal. When the intensity of the light beam reaches the target intensity after the generation of the positional signal, a second drive signal is generated in a second cycle longer than the first cycle instead of the first drive signal and is supplied to the semiconductor laser. The second drive signal is determined in accordance with the comparison result latched in the latch circuit.