Image forming apparatus and method

Abstract

The image forming apparatus forms an image on a recording medium by using coloring materials of at least three colors of cyan, magenta and yellow, wherein: at least one of the cyan and magenta color materials is a coloring material of lower density than the yellow; and ink brightness or perception of graininess on the recording medium is substantially the same for each of the three coloring materials, if recording is carried out on the recording medium according to any one condition of: a first condition wherein recording is carried out using substantially the same dot size for each color, at a recording rate of 100%; a second condition wherein recording is carried out using substantially the same dot size for each color, at the same recording rate for each color with respect to the surface area of the recording medium that is to be evaluated, and at an overlap rate of 100%; and a third condition wherein recording is carried out using substantially the same dot size distribution for each color, at the same recording rate for each color with respect to the surface area on the recording medium that is to be evaluated, and at an overlap rate of 100%, where a maximum number of dots recorded onto the recording medium per unit surface area is taken as N, a number of dots actually recorded per unit surface area as r, a sum of a surface area covered by the recorded dots per unit surface area as c, a total surface area of the dots recorded per unit surface area as Ds, and the unit surface area as S, and the following equations are established: a recording rate=(r/N)×100(%), a coverage rate=(c/S)×100(%), and an overlap rate={Ds/(S×Coverage rate/100)}×100(%)=(Ds/c)×100(%).