Patent ID: 7206531

Claim:
An image forming apparatus comprising: image forming means for forming a toner image using light color toner and dark color toner, which have the same hues and which have different densities, wherein said image forming means effects image formation using only the light color toner in a first image density region and effects image formation using both of the light color toner and the dark color toner in a second image density region; test image forming means for operating said image forming means to form, using the light color toner and the dark color toner, a plurality of test patterns, which have different densities, for density control, wherein the test patterns formed by said test image forming means using said image forming means include groups of test patches at density difference intervals which are smaller in the second image density region than in the first image density region; detecting means for detecting the test patterns; and control means for controlling an image forming condition of said image forming means in accordance with an output of said detecting means.