Patent ID: 6937371

Claim:
An optical scanner, comprising: a first optical system having a coupling lens that couples a light flux from a light source, the first optical system being disposed in an environment in the optical scanner where the temperature is approximately a first temperature T 1 ; a second optical system that forms the light flux into a line image on a deflector, the line image extending in a horizontal scanning direction; a third optical system having first and second optical elements and a scanning image formation device that condenses the light flux deflected by the deflector as an optical beam spot on a surface to be scanned; and a temperature distribution generation unit configured to control the first temperature T 1 near the first optical element, and a second temperature T 2 near the second optical element such that T 1 >T 2 , wherein an absolute value of a lateral magnification in the horizontal scanning direction of an optical system, which includes the first optical system, the second optical system, and the third optical system, is set larger than an absolute value of a lateral magnification in a vertical scanning direction of the optical system.