FIG. 2 is a diagram explaining a toner application amount. The image feature quantity in an area determined in advance within a page is found by the CPU 103 and the printer controller 132 of the printer 130 is notified of the image feature quantity. FIG. 2 shows the toner application amounts in pixels on a certain page. The toner application amount having the maximum value within the page of the toner application amounts of objects whose size is larger than or equal to a predetermined size is taken to be the maximum toner application amount and the quotient obtained by dividing the sum of the toner application amount of each pixel by the total number of pixels is taken to be the average print ratio. Further, the quotient obtained by dividing the sum of the pixels whose toner application amount is 0 (white) by the total number of pixels is taken to be the coverage. Then, the printer controller 132 performs temperature control at the time of fixing a toner image onto a sheet, inter-sheet control at the time of sheet conveyance, and the like based on the notified image feature amount.

(Configuration of Image Processing Unit)

FIG. 3 is a block diagram showing the internal configuration of the image processing unit 105. The image processing unit 105 includes data transfer units 201 and 202, a binary image compression/decompression unit 211, a multivalued image compression/decompression unit 212, a modification unit 213, a RIP unit 214, and a binarization unit 215. In the following, each unit is explained.