Patent Number: 8,441,512

Title: Optical scanner and image forming apparatus addressing uneven birefringence distribution of a scanning lens

Abstract: An optical scanner includes a light source, a deflector and a scanning optical system. The scanning optical system includes a first optical system including at least one resin scanning lens, and a second optical system between the target surface and one resin scanning lens. The second optical system includes at least one of a folding mirror(s) and a glass sheet(s), wherein m1+g2=m2+g1 is satisfied wherein m1 and g1 are respectively number of the folding mirror(s) and number of the glass sheet(s) to which the first ray has a shorter optical path than the second ray does, m2 and g2 are respectively number of the folding mirror(s) and number of the glass sheet(s) to which the first ray has a longer optical path than the second ray does.

Inventors: Tatsuno; Hibiki (Kanagawa, JP), Ichii; Daisuke (Kanagawa, JP), Arai; Nobuyuki (Kanagawa, JP)

Assignee: Ricoh Company, Limited

International Classification: B41J 15/14 (20060101); B41J 27/00 (20060101)

Expiration Date: 2021-05-14 0:00:00