Patent ID: 8103193

Claim:
An image forming apparatus having a color mode in which a color image is formed on a recording medium by rotating and driving a plurality of photoreceptor drums, and a monochromatic mode in which a monochromatic image is formed on a recording medium by a single photoreceptor drum of the plurality of photoreceptor drums by rotating and driving the single photoreceptor drum, the image forming apparatus comprising: a first motor which rotates only the single photoreceptor drum of the plurality of photoreceptor drums; a second motor which rotates the plurality of photoreceptor drums; a transmission member, which is capable of being switched between a transmitted state where the second motor transfers a drive force to the single photoreceptor drum and a non-transmitted state where the second motor does not transfer the drive force to the single photoreceptor drum; and a controller which controls a rotation speed of the second motor and a switching of the transmission member between the transmitted state and the non-transmitted state, wherein the controller switches the transmission member to the non-transmitted state while executing an image formation in the monochromatic mode, and when a command to execute a next image formation is not instructed after having executed the image formation in the monochromatic mode, switches the transmission member to the transmitted state after a phase adjusting process that adjusts a phase of each photoreceptor drum has been completed, and controls the second motor to execute a slight rotation operation which executes a slight rotation at every prescribed period of time by synchronizing the plurality of photoreceptor drums including the single photoreceptor drum with each other through the transmission member after the transmission member has been switched to the transmitted state.