An image forming apparatus includes a black image forming unit that can be used in a black monochrome mode to form supply toner images corresponding to color patches and cause the supply toner images to be carried by an intermediate transfer belt. During the black monochrome mode, a fur brush comes into contact with the supply toner images, so that discharge products are removed from the fur brush. Thus, when the black monochrome mode ends and a full-color mode is returned, the color patches transferred to a secondary transfer roller can be sufficiently removed by single passage and no backside contamination of a recording material occurs.