TONER CARTRIDGE, TONER SUPPLY MECHANISM, AND SHUTTER

This toner cartridge is provided with: a container provided with an accommodation section for accommodating a toner, and a discharge port for discharging the toner from the accommodation section to a receiving device; and an opening/closing member provided with a closing part for closing the discharge port, and an engagement part capable of moving relative to the closing part, said opening/closing member being capable of rotating relative to the container, between an open position (a) in which the closing part is made to open the discharge port, and a closed position (b) in which the closing part is made to close the discharge port. The engagement part is capable of moving relative to the closing part, between: an engagement position (c) for engaging with the receiving device so that a force for moving the opening/closing member from the open position to the closed position is received when the toner cartridge is removed from the receiving device; and a withdrawn position (d) withdrawn from the engagement position. Movement of the engagement part from the withdrawn position to the engagement position accompanies rotation of the opening/closing member from the closed position to the open position.