Patent ID: 7170536

Claim:
A light beam scanning apparatus comprising: a plurality of light sources which generate laser beams, respectively; a detection sensor which detects power levels of the respective laser beams of the plurality of light sources; a light power detection circuit which provides the light power levels detected by the detection sensor as detected signals; a plurality of capacitors which respectively hold voltages to decide emission power levels of the light sources; an emission power control section which compares a value of a light power signal from the light power detection circuit with a predetermined value, adjusts a terminal voltage of the corresponding capacitor based on a result of the comparison, and adjusts a driving current of each of the light sources based on the terminal voltage of the capacitor to control each emission power level of the light sources; and a correction section which corrects a reduction in light power of the light source in accordance with a reduction in electric charges applied to each capacitor during a plurality of scanning operations of the laser beam.