Patent ID: 8091974

Claim:
An image forming apparatus comprising: a plurality of image recording elements that record with a plurality of coloring materials on a recording medium and form an image, at least one of the plurality of image recording elements provided for each of the coloring materials, the coloring materials comprising a black color coloring material, a cyan color coloring material, a magenta color coloring material, and a yellow color coloring material; a control unit that controls the plurality of image recording elements such that detection images of two coloring materials having different brightness of the plurality of coloring materials overlap each other on the recording medium, and the control unit controls such that the detection image of the black color coloring material and the detection image of the cyan color coloring material overlap each other, and the detection image of the magenta color coloring material and the detection image of the yellow color coloring material overlap each other; a monochromatic sensor that reads a portion of the detection images in which said two coloring materials overlap each other; and a detection unit that detects whether or not each of the respective image recording elements that record said two coloring materials are functioning normally based on an output value corresponding to brightness of the monochromatic sensor when the monochromatic sensor reads the portion of the detection images in which said two coloring materials overlap each other.