Image forming apparatus

An image forming apparatus to and from which a first cartridge containing a first developer and a second cartridge containing a second developer are attachable and detachable, the image forming apparatus comprising:

• a first developing unit including:
• a first container for containing the first developer supplied from the first cartridge;
• and
• a first developing member configured to develop an electrostatic latent image formed on a photosensitive member using the first developer contained in the first container;
• a second developing unit including:
• a second container for containing the second developer supplied from the second cartridge;
• and
• a second developing member configured to develop the electrostatic latent image formed on the photosensitive member using the second developer contained in the second container;
• a rotatable rotary including the first developing unit and the second developing unit;
• a drive mechanism configured to drive the rotary to rotate the rotary;
• and
• a controller configured to control the drive mechanism,
• wherein the first developer in the first cartridge is supplied to the first container by being discharged from a first discharge opening formed in the first cartridge to a first receiving opening formed in the first container,
• the rotary is configured to assume:
• a first feeding orientation in which a direction from the first discharge opening to the first receiving opening has a vertical downward component;
• and
• a first developing orientation in which the first developing member is capable of developing the electrostatic latent image on the photosensitive member,
• the controller comprises:
• at least one memory storing instructions;
• and
• at least one processor that is in communication with the at least one memory and that, when executing the instructions, cooperates with the at least one memory to execute processing, and
• the processing includes controlling the drive mechanism to perform at least two times an acceleration/deceleration operation in which the rotary accelerates and thereafter decelerates, during a period in which the rotary rotates from the first feeding orientation to the first developing orientation.