The image forming apparatus is capable of executing a color mode for forming images of a plurality of colors using the plurality of developer bearing members, and a mono-mode for forming images of mono color using one developer bearing member of the plurality of developer bearing members. The control unit, when the color mode is executed, determines the charging bias and, the first laser power and the second laser power for respective image bearing members, based on information about the plurality of image bearing members. The control unit, when the mono-mode is executed, determines the charging bias and, the first laser power and the second laser power to image bearing member for mono-mode, based on information about image bearing member for mono-mode.