Patent ID: 6917451

Claim:
An image reading apparatus comprising: a first light transmitting member to be opposed to an original; first reading means for reading an image of the original through said first light transmitting member; and a first standard portion which is read by said first reading means to perform shading compensation; a second light transmitting member to be opposed to an original; second reading means for reading an image of the original through said second light transmitting member; and a second standard portion which is read by said second reading means to perform shading compensation, wherein said first light transmitting member, said first reading means, and said first standard portion are provided on a first side of the original, and wherein said second light transmitting member, said second reading means, and said second standard portion are provided on a second side, opposite to said first side, of the original, wherein said first reading means is able to read a stationary original and an original being conveyed, and wherein said second reading means reads an original being conveyed, and wherein a width of said second standard portion is larger than a width of said first standard portion in a direction perpendicular to a direction in which the original is conveyed.