Patent ID: 8605319

Claim:
A document reading apparatus communicable with an image processing apparatus, comprising: a conveying unit which conveys a document; a first reading unit which reads an image on a first side of the document conveyed by the conveying unit; a second reading unit which reads an image on a second side of the document conveyed by the conveying unit; a storage unit which stores image data output from the first and second reading units; a transmitter unit which transmits the image data stored in the storage unit to the image processing apparatus; and a control unit which selects a mode in accordance with a length of the document in a conveyance direction, the control unit which, in case that the length of the document is equal to or less than a predetermined length, selects a first mode, the control unit which, in case that the length of the document is longer than the predetermined length, selects a second mode, wherein, in the first mode, the control unit causes the conveying unit to convey the document to a reading position of the first reading unit without waiting for an instruction to start transferring from the image processing apparatus, the control unit causes the first reading unit to read the image on the first side of the document conveyed by the conveying unit, causes the storage unit to store the image data of the first side read by the first reading unit, and causes the storage unit to store the image data of the second side read by the second reading unit, and the control unit causes the transmitter unit to transmit the image data of the first and second sides stored in the storage unit to the image processing apparatus according to the instruction to start transferring from the image processing apparatus, and in the second mode, the control unit causes the conveying unit to convey the document to the reading position of the first reading unit according to the instruction to start transferring from the image processing apparatus, and causes the first reading unit to read the image on the first side of the document conveyed by the conveying unit, the control unit causes the transmitter unit to transmit the image data of the first side read by the first reading unit to the image processing apparatus without storing in the storage unit, the control unit causes the storage unit to store the image data of the second side read by the second reading unit, and causes the transmitter unit to transmit the image data of the second side stored in the storage unit to the image processing apparatus.