An image forming device includes a first medium container for a first printing medium; a second medium container for a second printing medium; a medium feeder for feeding one of the first and second media from one of the first and second medium containers; a special process unit that performs a special process on the first printing medium fed by the medium feeder when image data, including instruction information instructing the special process, is received; a detector that detects a characteristic of the first printing medium; a special process capability determination unit for determining whether or not the special process can be performed based on the characteristic; and a control unit that ejects the printing medium and that causes the second medium to be fed from the second medium container when the special process capability determination unit determines that the special process cannot be performed.