An image forming device includes an image forming unit that forms an image including at least one of a user-requested image and a test image onto a recording medium, a controller that controls the image forming unit to form a test image including a mixed color on the recording medium, a transporting path that transports the recording medium on which the test image is formed by the image forming unit, an image detecting unit disposed at the transporting path that detects the test image formed on the recording medium, and a calibration unit that performs a color calibration process based upon the test image detected by the image detecting unit.