An ejection malfunction nozzle detecting unit prints a test pattern and detects ejection malfunction nozzles on the basis of a scanned image of the test pattern. The ejection malfunction nozzle detecting unit classifies the ejection malfunction nozzles into periodical nozzles that periodically appear with a specific period in a primary scanning direction and non-periodical nozzles other than the periodical nozzles; for the periodical nozzles, stores the specific period and an offset as the ejection malfunction nozzle data into a storage device, and for the non-periodical nozzles, stores the ejection malfunction nozzle data that individually indicates positions of the non-periodical nozzles into the storage device. A correction processing unit performs the correction process for the periodical nozzles on the basis of the specific period and the offset, and the correction process for the non-periodical nozzles on the basis of the positions of the non-periodical nozzles.