Patent ID: 7133165

Claim:
An image reading apparatus comprising: an image reading unit adapted to read a document; a driving unit adapted to move said image reading unit; a position detecting unit adapted to detect a position of said image reading unit to move said image reading unit by said driving unit; a storing unit adapted to store position information in a case that said position detecting unit detects that said image reading unit is placed at a reference position; and an updating unit adapted to update the position information stored in said storing unit, wherein, in the case that said image reading unit does not detect an image for detecting a position after said image reading unit is moved to the reference position by said driving unit on a basis of the position information stored in said storing unit, said driving unit moves said image reading unit to an end of a movable range and moves said image reading unit in a direction opposite direction from the end of the movable range to update the position information by said updating unit.