The conversion of the dot percentages using the first conversion table Td1 and the second conversion table Td2 is performed for the gradation data Dh by the defective nozzle corrector 95. Here, the first conversion table Td1 converts the dot percentages of the pixels Px corresponding to the normal nozzles Nn having no discharge defect by the first rate Rd1 lower than 100%, and the second conversion table Td2 converts the dot percentages of the pixels Px corresponding to the surrounding nozzles Na located around the defective nozzle Nd by the second rate Rd2 higher than the first rate Rd1. Then, the shading correction is performed for the defect complemented gradation data Dc obtained by converting the dot percentages in this way by the shading corrector 96.