| 摘要 |
PROBLEM TO BE SOLVED: To prevent an image forming action from being interrupted from time to time by toner replenishing. SOLUTION: In the device, when the concentration of a developing device for one color among the four developing devices becomes <= a specified value A (for example, 4%), the copying is stopped. Then, toner replenishing from a toner hopper to the developing device is started not only for the developing device where the toner concentration is <= the specified value A but even for those among the other developing devices where the toner concentration is <=a specified value B. Toner replenishing is successively stopped from the developing device where the toner concentration becomes >= a specified value C. Copying is started when the toner concentration of all of the developing devices is >= the specified value C. |
