An object of the present invention is to perform printing an image onto both sides of a sheet with high accuracy, even if the sheet is large. A sheet and a feeder YH are used. The sheet has perforations formed at both ends of the sheet for sheet feed, and a feeder includes a drive roller 13 and two pin tractors 14, the drive roller rotating to drive the sheet in contact with the sheet, and the pin tractors including a plurality of pins to engage the perforations and being disposed in both ends of the drive roller to rotate to drive the sheet with a coaxial rotational driving force with the drive roller. The sheet is disposed in the feeder, and, in this state, the sheet is conveyed synchronously with movement of the pins to print an image onto one side of the sheet. The sheet is turned, onto one side of which printing has been performed, inside out and is disposed in the feeder, and, in this state, the sheet is conveyed synchronously with the movement of the pins to print an image onto another side of the sheet.