An accumulating unit accumulates image data of an original read by a reading unit. A combining unit combines the image data accumulated in the accumulating unit in a single printing sheet according to a predetermined copy mode. An output unit prints and outputs the image data according to the copy mode. An input unit receives an input of a read instruction. When a total number of originals read by the reading unit is smaller than a total number of originals specified in the copy mode and when the input unit does not receive an input of the read instruction within a predetermined time, a discard determining unit discards the image data accumulated in the accumulating unit, and finishes a printing process.