Patent ID: 7864374

Claim:
An image forming method that forms an image by a plurality of ink-jet heads of line type, which contain first inks having secondary chromatic colors, based on an input image, the method comprising: forming a test pattern, which uses a color chart with entire colors of second inks, by the ink-jet heads while using a normal color conversion table for converting a first color space of the input image into a second color space of the formed image, the second inks including the first inks; comparing data obtained by scanning the formed test pattern with second color space data of the test pattern, and identifying a non-matching color portion as a non-ejection color and a line position containing a non-ejection nozzle thereof; preparing a special color conversion table for converting the first color space in which one color of the second inks is omitted from the normal color conversion table into a second color space reproducing a color closest to the input image, the special color conversion table being provided with respect to each omission ink; and setting and using the special color conversion table for the omission ink corresponding to the non-ejection color at the line position containing the identified non-ejection nozzle.