Patent ID: 8879126

Claim:
An image reading device comprising: a housing defining a conveying path for conveying sheets having first and second sides; a first reading unit configured to read data on the first sides of the sheets conveyed along the conveying path; a second reading unit disposed downstream of the first reading unit with respect to the conveying path, the second reading unit configured to read data on the second sides of the sheets conveyed along the conveying path; and a controller configured to: determine, based on first read data obtained from the first side of a first sheet with the first reading unit before the first sheet has arrived at the second reading unit, whether an image is formed on the first side of the first sheet; control the first reading unit to continue reading the first side of the first sheet to acquire second read data including the first read data and data different from the first read data, and the second reading unit does not obtain data from the second side of the first sheet, when the controller determines that an image is formed on the first side of the first sheet; and control the second reading unit to read the second side of the first sheet to acquire third read data different from the first and second read data and stop the reading of the first side of the first sheet by the first reading unit, when the controller determines that an image is not formed on the first side of the first sheet.