Patent ID: 8355184

Claim:
An image reading device which reads an image from a document, comprising: a light source part in which plural point light sources are arrayed in parallel to a main scanning direction; a line sensor part in which plural light quantity sensors are arrayed in parallel to the main scanning direction; a reduction optical system containing a lens and focusing a reflected light beam, indicating image information of a document irradiated by a light beam from the light source part, on the line sensor part to read the image information; and a control part configured to control a quantity of irradiating light of each point light source of the light source part in accordance with an optical characteristic of the lens of the reduction optical system, wherein the plural point light sources in the light source part are arrayed into a set of point light source blocks, and the image reading device comprises an irradiating light quantity control part configured to control a quantity of irradiating light of each point light source or each point light source block which irradiates one of reading positions on the document, based on a quantity of irradiating light of a point light source or a point light source block which irradiates an optical axis position of the reduction optical system, a distance between the optical axis position and a corresponding one of the reading positions, and a distance of an optical path between a center of the lens and a surface of the document.