Image forming apparatus and toner refilling method therefor

An image forming apparatus for printing on a paper, the image forming apparatus comprising:

• a developing equipment that develops an image on a photoreceptor by a two-component developer for printing;
• a reserve tank that, as toner is supplied from a detachably connected toner cartridge, supplies the toner to the developing equipment by connecting to the toner cartridge to the developing equipment;
• a detecting device that detects a new toner cartridge being mounted;
• a consumed toner amount calculation unit that calculates an amount of consumption of the toner consumed by the developing equipment for printing from printing data;
• a control device that determines necessity of exchange of the toner cartridge in the image forming apparatus according to the amount of consumption of the toner calculated by the consumed toner amount calculation unit;
• and
• a storage unit that stores an amount of remaining surplus toner remaining in the new toner cartridge, wherein the amount of remaining surplus toner is a difference between an amount of charged toner which charges the new toner cartridge mounted on the reserve tank and an amount of full accommodation toner which fills a predetermined reserve tank,
• wherein the control device is configured to
• display on a display device, in response to a notification from the detecting device that the new toner cartridge is mounted on the reserve tank, an indication of an amount of toner that is consumable until a next exchange of the toner cartridge as consumable information, while the image is being developed on the photoreceptor by the developing equipment;
• control a printing operation of the image forming device according to a user instruction;
• obtain the amount of toner consumption calculated by the consumed toner amount calculation unit as an amount of toner used in the developing equipment from a time that the new toner cartridge is mounted to a current state;
• and
• display on the display device, while the image is developable on the photoreceptor by the developing equipment when whether the amount of toner consumption exceeds the amount of remaining surplus toner stored in the storage unit is determined and the amount of toner consumption exceeds the amount of remaining surplus toner, an instruction informing the user of exchange information that encourages the user to exchange a mounted toner cartridge with another new toner cartridge.