An image formation controller judges whether or not a tint block has been detected by a tint block processor upon judging that an automatic color determination mode is set in a multi functional peripheral. The image formation controller causes an image forming section to perform a monochromatic image forming operation if the tint block is a chromatic tint block when the tint block was detected by the tint block processor. On the other hand, the image formation controller causes the image forming section to perform an image forming operation corresponding to a determination result by an ACS processor when no tint block was detected and when the tint block was determined to be a monochromatic tint block.