Patent ID: 6731884
Filing Date: 2004-05-04
Classification: G03G

Abstract:
A toner supply device in an image forming apparatus having a plurality of developing devices, wherein said plurality of developing devices are changeable between a developing position and a standby position, comprising:a calculator for calculating an estimated toner coverage rate of a first print developed by a first developing device at the developing position; a toner density detector for detecting, at the standby position, an actual toner density of a developing agent layer of the first print after the first developing device is changed from the developing position to the standby position; and a controller configured to: begin replenishment of a required amount of toner to the first developing device when said first developing device is changed from the standby position to the developing position for a second print if the estimated toner coverage rate of the first print is equal to or less than a predetermined value, and begin replenishment of the required amount of toner to said first developing device before said first developing device is changed from the developing position when the first print is developed to the standby position if the estimated toner coverage rate of the first print is higher than the predetermined value.