Image forming apparatus, the charging amount calculation method and billing amount calculation program

摘要

PROBLEM TO BE SOLVED: To properly calculate, in printing an image including an achromatic part, toner usage when the achromatic part is converted into an ink color.SOLUTION: An image forming apparatus includes: an RGB-to-CMYK conversion unit 2211 that replaces part or all of achromatic pixels in a target image with ink pixels to form an ink replacement image; and a transfer toner amount conversion unit 2213 that calculates usage of ink toner and usage of other color toners used for printing the ink replacement image, on the basis of association information between an arbitrary color value related to the ink toner and other color toners and the amount of toner used per unit area.