| 摘要 |
PURPOSE:To miniaturize a device, to save a space, to control toner replenish ment with accuracy so that an image having high image quality is always obtained by uniformly replenishing the toner with the calculated toner quantity during a stirring means is driven from the end of developing up to a time just before developing at a following image forming stage is started. CONSTITUTION:For example, the maximum time capable of replenishing C(cyan) toner is defined with the time obtained just before developing at the following image forming stage (copying operation of copying one sheet of full-color copy) is started by a C developing device, a toner replenishment ratio is calculated based on the toner concentration of developer in the C developing device at this time, a target toner concentration and the developer capacity of the C developing device. A C toner replenishing motor 79 is controlled by a CPU 75 so that the C toner may be uniformly replenished at the toner replenishment ratio, and then, replenishing the C toner is finished just before developing by the C developing device at the following image forming stage is started. Thus, toner replenishing capacity can be made as little as possible even in the case that the required quantity of toner to be replenished is large. |
