Patent ID: 7962053

Claim:
A method of controlling a supply of a developer, the method comprising: sensing an amount of the developer; determining whether the sensed amount is equal to or less than a predetermined threshold; supplying the developer and repeating the sensing when a determination is made that the sensed amount is equal to or less than the threshold; and stopping the supplying of the developer when a determination is made that the sensed amount is greater than the threshold; wherein the sensing, the determining, the supplying and the stopping are performed during a warm-up operation; and wherein the supplying comprises: determining whether a warm-up completion time has passed when it is determined that the sensed amount is equal to or less than the threshold, and stopping the supplying of the developer when it is determined that the warm-up completion time has passed; and changing a given flag to a value indicating the result of comparing the sensed amount of the developer with the threshold, when it is determined that the warm-up completion time has passed; wherein said flag is analyzed at a future time to determine whether an amount of the developer is greater than the threshold.