An example image forming apparatus includes a main body, a driving motor, a developing cartridge, and a clutch. The developing cartridge includes a toner container, a mounting portion to receive a toner refill cartridge, a toner inlet portion to connect the mounting portion to the toner container, and a toner inlet shutter to be switched between a blocking location for blocking the toner inlet portion and an inlet location for opening the toner inlet portion. The clutch is to selectively transmit a driving force of the driving motor to the toner inlet shutter.