| 摘要 |
PURPOSE:To perform tentative operation in case of a abnormality display by comparing the output L of a photodetecting element which detects toner density with the upper-limit and lower-limit values of an output area used for toner supplementation, and further comparing it with a specific level when necessary. CONSTITUTION:The upper-limit value Lmax and lower-limit value Lmin of the output area of the photodetecting element which is used for toner supplementation are set to 4.8 and 2.5V respectively. When the photodetecting element generates an output L, whether the output L is 4.8>=L<=2.5 or not is judged and when so, a normal toner supplementation system is operated. Namely, toner is supplemented according to the large/small relation between the output L and an output L0 corresponding to optimum toner density. When this condition is not satisfied, the normal toner supplementation system is turned off and the abnormality display is performed; a copying machine, etc., are still in operation at this state to perform tentative copying operation, etc. |
