Patent ID: 7315409

Claim:
An optical scanning device, comprising: a light source emitting a light beam; an optical deflecting part deflecting the light beam emitted from said light source; a scan surface to be optically scanned; and a scanning and imaging optical system directing the deflected light beam to said scan surface so as to perform optical scanning, said scanning and imaging optical system including two scanning lenses, a first scanning lens, of said two scanning lenses, being nearer to the optical deflecting part and having a power only in a main scanning direction, and a second scanning lens, of said two scanning lenses, being nearer to said scan surface and satisfying |(1/Rm1)−(1/Rm2)|·L<0.1, where Rm1 is a radius of curvature in the main scanning direction of an entering surface of said second scanning lens, Rm2 is a radius of curvature in the main scanning direction of an exiting surface of said second scanning lens, and L is an optical path length from a point of deflection of said optical deflecting part to the scan surface.