Image reading apparatus

Abstract

There is disclosed an image reading apparatus in which the scanning optical system having a slit is caused to scan in a short-side direction of the slit, and light passed through the slit and reflected from or transmitted through an original is guided to a solid-state image pickup element through an optical image forming element so that the image is formed on the solid-state image pickup element and is read. In the apparatus, opening portions for detecting a shift in relative positional relationship between the slit and the solid-state image pickup element are formed in both end portions of the slit in its longitudinal direction corresponding to a portion other than an effective image region of the solid-state image pickup element.

Dependencies are inferred from the claim text.