Optical scanning device and image forming apparatus

An image forming apparatus for performing image formation by forming a latent image on an image carrier by scanning a light beam with an optical scanning device and developing the latent image on the image carrier into a visible image, wherein the optical scanning device comprises:

• a light beam generating unit configured to generate a light beam;
• a light beam deflecting unit configured to receive the light beam and deflect/emit the light beam with a deflecting mirror;
• a light beam ON/OFF control unit configured to control the light beam generating unit so that the light beam deflected by the light beam deflecting unit is turned ON/OFF in a particular optical scanning range while the light beam is being reciprocally scanned;
• and
• a light beam scanning time measuring unit configured to obtain a measurement value by measuring a time or time intervals at which the light beam passes a reference point while being reciprocally scanned, the reference point being provided at an arbitrary position on an edge part of an entire light beam scanning region that is away from a center part of the entire light beam scanning region, wherein:
• timings at which the light beam is turned ON/OFF are controlled in accordance with the measurement value.