A channel selection section selects whether the subsequent processing to the image data is executed by image distribution precedence processing or by gradation lowering precedence processing in accordance with channel information of the image data. That is, in regard to the channels of C, M and K with relatively high density among inks, the image distribution precedence processing excellent in robustness is selected. On the other hand, in the ink of the color with high brightness or low density, even if the print position of the dot is shifted, the density change due to this shift is not so much large. It is possible to restrict an increase in the processing load due to executing the gradation lowering processing after the distribution processing to each of the plural divided images by thus not selecting the image distribution precedence processing in consideration of the robustness.