Patent ID: 8320028

Claim:
An optical scanning apparatus, comprising: a light source that emits a predetermined number of laser beams, the laser beams being arranged in a sub-scanning direction on a recording medium to form an imaginary single beam; an optical unit that simultaneously scans the laser beams in parallel on the recording medium; a first controller that changes a dot size of the laser beams in a main scanning direction; and a second controller that changes the predetermined number based on the change of the dot size of the laser beams, wherein the dot size is changed relative to a reference dot size L, wherein the laser beams are arranged in the sub-scanning direction at an interval of 1/M times L, where M is an integer of 2 or more, wherein the second controller switches the predetermined number between at least a first number N 1 and a second number N 2 , wherein the light source comprises beam generating elements each generating respective one of the laser beams, and wherein a number of the beam generating elements is equal to a common multiple of the first number N 1 and the second number N 2 .