Abstract:
The amount of achromatic toner used is reduced without decreasing adhesive force. A printer apparatus derives the densities of chromatic toner corresponding to the tone values of image data in the cyan, magenta and yellow format, and derives a total density by adding up the respective densities of the chromatic toner of cyan, magenta, and yellow. Then, the apparatus compares a threshold density such as 100% or 60% with the total density of the chromatic toner of cyan, magenta, and yellow. When the total density is higher than the threshold density, the apparatus sets the density of achromatic toner to 0. When the total density of the chromatic toner of cyan, magenta, and yellow is not higher than the threshold density, the apparatus sets the density of the achromatic toner to a value acquired by subtracting the total density from the threshold density.