Image reading device including an optical unit for reading a document image, image forming apparatus therewith, and optical unit for reading a document image

摘要

An image reading device has an optical unit and a rail portion formed of sheet metal. The optical unit is scanned in the sub scanning direction to read an image on a document on a contact glass. The rail portion slidably supports the optical unit. The optical unit has a sliding portion which slides on the rail portion while making contact therewith, and at least one pair of gripping portions which grip the rail portion. The surface of the sliding portion has a substantially arc-shaped cross section. The rail portion has two inclined surfaces that make contact with the substantially arc-shaped surface at two points.