Patent ID: 8755092

Claim:
An image reading apparatus comprising: an array substrate in which a plurality of point light sources is arrayed and mounted in a linear shape at a predetermined interval along the main scanning direction; a light guide member disposed on a surface of the array substrate that mounts the plurality of point light sources, and guiding light from the plurality of point light sources to the document surface; a frame for fixing the light guide member and the array substrate; a positioning portion that determines the positional relationship of the frame with the light guide member and the array substrate in a configuration in which an incident surface of the light guide member is in proximity to or in contact with the plurality of point light sources; and an image reading unit that uses reflected light when illuminating light from the plurality of point light sources through the light guide member onto the document surface to thereby read the document image, wherein the positioning portion comprises: a first positioning hole formed in the array substrate; a second positioning hole formed in the light guide member; and a first positioning pin provided on the frame, and inserted and fitted into both of the first positioning hole and the second positioning hole.