Patent ID: 7796310

Claim:
An image reading apparatus comprising: a first reading unit disposed on one side of a conveyance path of an original and having a first light source for emitting light to one surface of the original, and adapted to receive the light emitted from the first light source and subsequently reflected at the one surface of the original and adapted to read an image of the original; a second reading unit disposed on the other side of the conveyance path and having a second light source for emitting light to be received by said first reading unit, an optical opening for causing the light emitted from the second light source and subsequently received by said first reading unit to pass therethrough toward said first reading unit, and a reference member disposed so as to be movable between a position at which the optical opening is closed and a position at which the optical opening opens and to be read by said first reading unit, and adapted to receive the light emitted from said second light source and subsequently reflected at the other surface of the original and adapted to read the image of the original; and a control unit adapted to provide a control of detecting the original on the basis of the resultant output of said first reading unit upon receipt of the light emitted from said second light source.