An image forming apparatus includes a first developing cartridge including a first developing roller and a first projection, the first developing cartridge being detachably mounted to a first mounting portion of a frame such that the first developing cartridge is movable relative to the frame between a position where the first developing roller contacts a first photosensitive drum and the first projection is located in a first lower position and a position where the first projection is located in a first upper position above the first lower position. The apparatus also includes a first contacting member contactable with the first projection. The force applying portion is configured to apply a force to the first developing cartridge such that the first projection being held in the first upper position by the first contacting portion is moved to the first lower position.