Image formation unit, image formation apparatus, and developer cartridge

An image formation unit comprising:

• a main body;
• and a developer cartridge that is configured to be detachably attached to the main body, wherein
• the developer cartridge comprises:
• a supply port provided at one end side of the developer cartridge in an orthogonal direction orthogonal to a longitudinal direction and configured to supply a developer stored in the developer cartridge;
• an opening/closing member configured to open and close the supply port;
• a restriction portion provided on the one end side in the orthogonal direction of the developer cartridge and configured to restrict movement of the opening/closing member from a closed position to an open position;
• a first engagement portion provided on one end side in the longitudinal direction of the developer cartridge;
• and
• a first contact portion provided on the other end side in the longitudinal direction of the developer cartridge,
• the main body comprises:
• a reception port provided at a position where the reception port is connected to the supply port in a state where the developer cartridge is attached to the main body and configured to receive the developer from the supply port;
• a second engagement portion provided at a position opposite the longitudinal one end side of the developer cartridge, the second engagement portion being configured to engage with the first engagement portion of the developer cartridge when the developer cartridge reaches a correct position during attachment of the developer cartridge to the main body;
• a restriction release portion configured to release the restriction on movement of the opening/closing member by contacting the restriction portion when the developer cartridge reaches the correct position;
• and
• a second contact portion provided at a position opposite the longitudinal other end side of the developer cartridge, the second contact portion being configured to contact the first contact portion of the developer cartridge when the developer cartridge reaches an incorrect position during attachment of the developer cartridge to the main body, thereby maintaining separation between the restriction portion and the restriction release portion.