Cartridge, image forming apparatus and method of controlling the image forming apparatus

摘要

In a developer container, there are provided a flat antenna for measuring the predetermined range of the developer-remaining-amount, and a plate antenna for measuring the predetermined amount or less of the developer-remaining-amount. When the detected value by the flat antenna is a predetermined value or greater, the minimum detected voltage value of the plate antenna is measured, and this value is stored as PAF (plate antenna full) in the storing means of a cartridge. During the measurement of the predetermined value or less of the developer by the plate antenna, the detected voltage value is calculation-processed and corrected by PAF to thereby obtain the developer amount.