Light beam scanning apparatus and image forming apparatus

An image forming 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;
• 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;
• 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;
• and
• an image forming section which modulates a laser beam having emission power controlled by the emission power control section, and scans the laser beam to form an image on an image forming medium.

A light beam scanning method comprising:

• generating laser beams from a plurality of light sources, respectively;
• detecting power levels of the respective laser beams of the plurality of light sources;
• providing the detected light power levels as detected signals;
• holding voltages to decide emission power levels of the light sources, respectively, by a plurality of capacitors;
• comparing a value of a light power signal from light power detection circuit with a predetermined value, adjusting a terminal voltage of the corresponding capacitor based on a result of the comparison, and adjusting a driving current of each of the light sources based on the terminal voltage of the capacitor to control the emission power;
• and
• correcting 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.