An image forming apparatus includes ink cartridges, image forming units, an ink-remaining-amount manager, a maintenance determiner, an information writer, an ink-amount estimator, and a maintenance-executability determiner. If an ink near-empty or empty state occurs in one of the ink cartridges due to image formation, the ink-amount estimator estimates an amount of ink required to execute the maintenance on the other ink cartridges based on the at least one of the need for and the type of maintenance determined by the maintenance determiner. If the maintenance-executability determiner determines that the maintenance is unexecutable on at least one of the other ink cartridges based on the required ink amount and a remaining ink amount, the maintenance-executability determiner determines that the unexecutable ink cartridge is at an ink near-empty or empty state and stops writing or updating information indicative of a spent state on the memory of the unexecutable ink cartridge.