A printer includes a data obtaining unit, a storage unit, an engine, and a printing unit. The data obtaining unit obtains, from print data stored in the storage unit, print data for sheets less than the maximum number of sheets dischargeable to a discharge tray as target print data and sends the target print data to the engine via the printing unit. The target print data includes first print data of odd pages and second print data of even pages. After printing the first print data on one side of sheets fed from a feed tray and discharges the sheets onto the discharge tray, the engine prints the second print data on the other side of the sheets manually returned from the discharge tray to the feed tray.