Image forming apparatus

An image forming apparatus comprising:

• a rotary which is rotatable and to which a cartridge is detachably attached;
• a drive source;
• a transmission device including a driving member and configured to transmit driving force of the drive source;
• and
• a moving device configured to be driven by the driving force transmitted via the transmission device to move the cartridge with respect to the rotary between an attached position and a retracted position retracted from the attached position, the moving device including a driven portion that is provided in the rotary and is configured to receive the driving force from the driving member,
• wherein the driving member includes
• a force transmission portion configured to engage with the driven portion to transmit the driving force, and
• an engaging portion configured to engage with the rotary such that movement of the driving member and the rotary with respect to each other in a manner that the force transmission portion and the driven portion separate from each other is restricted.