An image forming apparatus includes multiple image forming stations, and a controller for executing selectively a multi-color image mode or a monochromatic image forming mode, wherein in the monochromatic image forming mode, a first one of image forming stations which forms the image, and a second one which is upstream of the first image forming station exposes the image bearing members to a first image pattern and a second image pattern, respectively, and the controller determines the second image pattern in accordance with the first image pattern, and effects the exposure to the second image pattern.