Patent ID: 7088485

Claim:
An optical scanner that scans a surface of each of a plurality of latent image carriers with a corresponding light beam, comprising: an optical deflection unit that is rotatable and that deflects and reflects light beams, the optical deflection unit having two or more surfaces, along an axis of rotation of optical deflection unit, that deflect and reflect the light beams in different directions; a lens that takes-in the light beams reflected from the optical deflection unit and divides the light beams into a number of light beams equal to number of the image carrier; and a bending optical system corresponding to each image carrier, the bending optical system configured to guide the light beam output from the lens onto a surface of a corresponding one of the image carriers, wherein the light beams entering into the optical deflection unit include, at least one orthogonal beam that is orthogonal to the axis of rotation of the optical deflection unit, and at least one oblique beam that is oblique to a plane that is orthogonal to the axis of rotation of the optical deflection unit, and wherein the oblique beam satisfies the condition: 10<2 L ·tan θ+ d< 40 (millimeters) where θ is angle of incidence of the light beam with respect to the plane that is orthogonal to the axis of rotation of the optical deflection unit, d is distance between incident positions of the light beams, and L is a distance between the surfaces of the optical deflection unit and an image surface.