Patent ID: 7088476

Claim:
An image reading apparatus comprising: an original plate adapted to support an original; a longitudinal reading unit adapted to read an original image, said longitudinal reading unit including, in a frame, a light source, a light receiving unit, and an imaging unit adapted to form an original image on said light receiving unit; a supporting member adapted to support said frame of said longitudinal reading unit, said supporting member having a first engaging portion and a second engaging portion to engage with said frame of said longitudinal reading unit; a movement unit adapted to move said supporting member relative to said original plate in a direction perpendicular to a longitudinal direction of said longitudinal reading unit; a first positioning portion adapted to determine a position of said frame of said longitudinal reading unit relative to said supporting member in the longitudinal direction by engaging with said first engaging portion of said supporting member, said first positioning portion being provided substantially at a central portion of said frame of said longitudinal reading unit; and a second positioning portion adapted to determine a position of said frame of said longitudinal reading unit relative to said supporting member in a moving direction by engaging with said second engaging portion of said supporting member, said second positioning portion engaging with said second engaging portion while being afforded some degree of latitude in the longitudinal direction.