| 摘要 |
PURPOSE:To secure the control of development characteristic by making the relation between an output from a photodetecting element and toner adhesive quantity on a photosensitive body linear in case of controlling the output from the photodetecting element and the development characteristic. CONSTITUTION:A toner adhesive area formed on the photosensitive drum 1 is irradiated with light from a light emitting element 6 such as a light emission diode, etc., and reflected light at such a time is received by the photodetecing element 7 such as a photodiode, etc. An electrical signal is outputted from the element 7 corresponding to the toner adhesive quantity and transmitted to a concentration detection circuit 26, then converted into logarithmic value by a logarithm converter. By converting the output from the photodetecting element into logarithm, the relation between the toner adhesive quantity on the photosensitive body and the output becomes linear. Thus, toner concentration can always be kept accurate by setting the toner replenishing quantity constant in case of replenishing the toner according to the output from the photodetecting element. |
