| 摘要 |
PURPOSE:To accurately perform empty processing for a toner hopper by replenishing toner within a fixed period before image formation is started and performing the empty processing for the toner hopper when a toner density level is less than a toner replenishment level even after this toner replenishment. CONSTITUTION:A toner density sensor 14 detects the toner density in a developing tank 11 and inputs the detected value to a CPU 3. This toner density is indicated as 'H' or 'L' based upon preset constant density. The CPU 3 supplies toner to the developing tank 11 by rotating a toner supplementary roller 13 when the toner density is 'L'. When, however, the toner density in the developing tank 11 does not reach a sufficient value even after the toner replenishing operation, it is judged that the toner in the toner hopper is all consumed and a toner empty display is made at a display part and a copying process is inhibited from being performed. |
