Image forming apparatus including development cartridge having a development memory storing toner amount information

An image forming apparatus comprising:

• a main body;
• a development cartridge installable in the main body, the development cartridge comprising a development roller, a development chamber in which toner is storable, and a development memory;
• a toner cartridge installable in the development cartridge, the toner cartridge comprising a case in which toner is stored, a toner supply unit configured to supply toner from the case into the development chamber, and a toner memory;
• and
• a controller configured to:
• store, in the development memory, information regarding a cumulative received toner amount that is a cumulative amount of toner supplied from the case and received in the development chamber, and a cumulative toner consumption amount that is a cumulative amount of consumed toner;
• subtract the cumulative toner consumption amount from the cumulative received toner amount to find a difference, and cause the toner supply unit to supply a first predetermined amount of toner into the development chamber when the difference is equal to or smaller than a first threshold value;
• and
• store, in the toner memory, information regarding a cumulative supplied toner amount that is a cumulative amount of toner supplied by the toner supply unit from the case into the development chamber.