Patent ID: 7477437

Claim:
A laser scanner comprising: a light source; a first optical system for converting light emitted from the light source into convergent light in a main-scanning direction and into parallel light in a sub-scanning direction; a deflector for deflecting the light from the first optical system by sinusoidally oscillating a reflection surface; and a second optical system for condensing the light deflected by the deflector onto a surface to be scanned both in the main-scanning direction and the sub-scanning direction and also scanning the surface to be scanned with the light in the main-scanning direction at a constant speed, wherein the second optical system is composed of two lenses, a first lens arranged on a deflector side and a second lens arranged on a surface-to-be-scanned side, and wherein the first lens has a light incidence side surface and a light exit side surface both formed with a free curved surface, and has a negative refractive power in each of the main-scanning direction and the sub-scanning direction, and wherein the second lens has a free curved surface, and has a positive refractive power in the sub-scanning direction.