Patent ID: 8363287

Claim:
An image reading apparatus comprising: a first image sensor configured to read an image of a first side of an original thereby acquiring first image data, and a second image sensor configured to read an image of a second side of the original thereby acquiring second image data, wherein reading of the image of the first side of an original by the first image sensor and reading of the image of the second side of the original by the second image sensor can be performed simultaneously; a storage unit that temporarily stores therein the first image data and the second image data; a first input path through which the first image data acquired by the first image sensor is output to the storage unit, and a second input path through which the second image data acquired by the second image sensor is output to the storage unit; and an output path through which the first image data and the second image data are output from the storage unit to an image processing unit, wherein when a size of the original is equal to or smaller than a predetermined size, reading of the original is performed in a regular reading mode in which the first image data is stored in a first storage area of the storage unit though the first input path and the second image data is stored separately in a second storage area of the storage unit though the second input path, and when the size of the original is larger than the predetermined size, the first storage area and the second storage area are regarded as one storage area, and reading of only the first side of the original is performed in a ring buffer mode in which storing of the first image data in the one storage area through the first input path and outputting of the first image data from the one storage area to the image processing unit through the output path are performed in a parallel manner, and when the size of the original is larger than the predetermined size, and it is necessary to read the first and second sides of the original simultaneously, the one storage area is divided into the first storage area for the first side of the original and the second storage area for the second side, image data of an entire area of the first side is stored in the first storage area in the ring buffer mode, and image data of a specified area of the second side is stored in the second storage area.