Patent ID: 8009342

Claim:
An optical scanning device comprising: a vertical cavity surface emitting laser; a driving unit that controls modulation driving for the vertical cavity surface emitting laser; a coupling optical system that couples a beam output from the vertical cavity surface emitting laser; an aperture that is configured to define a beam spot diameter on a target surface; a deflecting unit that deflects a laser beam incoming from the aperture; and a scanning optical system that guides the laser beam incoming from the deflecting unit to the target surface, wherein the driving unit controls so as to satisfy conditions 1 and 2 below: P 1> P 100 condition 1 W m <W s condition 2 where P 1 is an amount of light at a time after a period T 1 corresponding to a minimum pixel unit has elapsed since beginning of light emission, P 100 is an amount of light at a time after a time period of 100×T 1 has elapsed since the beginning of light emission, W m is a static beam spot diameter in a main-scanning direction, and W s is a static beam spot diameter in a sub-scanning direction.