Patent ID: 8666264

Claim:
A toner refilling method for an image forming apparatus which comprises (i) a reserve tank which is integrally provided in a main body of the image forming apparatus and which does not include a detection sensor that directly detects whether or not a toner exists inside the reserve tank; (ii) a two-component developing equipment which is detachably connected to the reserve tank and which develops an image on a photoreceptor with a two-component developer for printing; (iii) a toner density sensor which detects a density of the toner in the two-component developing equipment; and (iv) a toner cartridge which is detachably connected to the reserve tank and which supplies the toner to the two-component developing equipment via the reserve tank, wherein the toner cartridge does not include a detection sensor that directly detects whether or not the toner exists inside the toner cartridge, the toner refilling method comprising: receiving a notification from a detecting device indicating that the toner cartridge which is an original toner cartridge is mounted on the reserve tank; starting a printing in accordance with the notification of the mounting of the original toner cartridge; determining an amount of remaining surplus toner remaining in the original toner cartridge by subtracting an amount of full accommodation toner for filling up the reserve tank from an amount of charged toner in the original toner cartridge; acquiring an amount of toner consumption using a dot counter which counts total printing data from a printing start to a current state; determining whether or not the amount of the toner consumption exceeds the amount of the remaining surplus toner, and when it is determined that the amount of the toner consumption exceeds the amount of the remaining surplus toner, exchange-informing a user to exchange the original toner cartridge with a new toner cartridge while operating the main body of the image forming apparatus; waiting for a notification of detection of the new toner cartridge which replaces the original toner cartridge; and informing the user of an amount of toner which can be consumed after the exchange to the new toner cartridge and proceeding with the printing, when the notification of detection of the new toner cartridge is received.