US Patent 7746522 Image reading device

A scanner unit includes a housing having an opening on its upper surface, a platen glass provided so as to be exposed from the opening on the upper surface of the housing, a carriage provided in the housing so as to be movable parallel with the platen glass, a linear CIS mounted on the carriage in a direction perpendicular to the moving direction to read the image of a document placed on the platen glass, roller units provided in the vicinity of both ends and central part with respect to the vicinity of the both ends of the CIS in the longitudinal direction so as to abut on the platen glass, and a coil spring provided in the carriage so as to force the CIS toward the platen glass.