A print-mode determination processor determines the print mode of a print job that is described in a page description language (PDL) and that has a print mode set to an automatic determination mode, using image data generated for a preflight check by a preflight checker that performs a preflight check of image data of a print job. The image data for a preflight check has a resolution lower than that of thumbnail image data and sufficient to determine whether to set a color print mode or a black-and-white print mode, such as presence or absence of a color part in the image data of the print job or the degree of the color part, so that the time required for generating and analyzing image data for print mode determination can be shortened.