Optical scanning apparatus, image forming apparatus using the same and method of regulating the optical scanning apparatus

An optical scanning apparatus, comprising:

• a plurality of light sources configured to emit light beams;
• and
• a rotary deflector configured to deflect the light beams,
• wherein a revolution number (Rm) of the rotary deflector is reduced to Rdef×(V/Vmax) if V/Vmax is greater than a value;
• and the revolution number (Rm) thereof is reduced to Rdef×(V/Vmax)×m and the number of the light beams is reduced to Ndef/m if V/Vmax is not greater than the value when the revolution number of the rotary deflector, or the revolution number thereof as well as the number of the light beams are changed in accordance with switching of a process linear velocity of an image forming apparatus, wherein V is a process linear velocity of the image forming apparatus;
• Vmax is a maximum process linear velocity thereof;
• Ndef is the number of the light beams at the maximum process linear velocity Vmax;
• and Rdef is the revolution number of the rotary deflector thereat;
• and m is a positive integer, and wherein Vmax is greater than V (Vmax>V).