| 摘要 |
PURPOSE: To suppress the deterioration of image quality after consecutive operation or during the consecutive operation by providing a means for adjusting the toner conc. of the developing unit, when the toner conc. lowering state is stored, after the consecutive operation of the image forming or in a state of idling. CONSTITUTION: At the time of the normal image forming, by the first toner conc. adjusting means, the feed back control for feeding the toner to the developing unit, corresponding to the toner conc. in the developing unit through the toner feeding means so as to maintain the toner conc. at the specified value. In the continuous operation of the image forming, when it is detected that the toner conc. in the developing unit becomes under the specified value, by the toner conc. detecting means, the conc. lowered state is stored by the toner conc. lowered state storing means, after the completion of consecutive operation or at the time of idling, the specified amount of the toner is forcedly fed to the developing unit, by the second toner conc. adjusting means, and moreover the developer composed of the toner and the carrier is stirred within the specified time in the developing unit. Thus, the toner conc. can be restored to the specified conc. |
