Patent attributes
A product of a predetermined time interval and the number of periods is set to be an integer multiple of a time (or agitation period) required for one rotation of an agitation member and also a light receiving state is detected when an interval signal is Hi. Therefore, the number of times that light cannot be received due to the agitation member (or the number of agitation influences) is constant within one period. Since the number of agitation influences is set to the constant number of times in one period and the influence of the agitation member is constant at the remaining developer amount ratio of 1/Light Receiving Ratio, the light receiving ratio appropriately indicating the remaining developer amount can be obtained and the remaining developer amount can be correctly detected.
