| 摘要 |
PURPOSE:To drive to rotate a detection probe with the rotation of a photosensitive drum and to quickly and accurately detect the density of toner by providing the detection probe on a specified position. CONSTITUTION:The detection probe 45 obtained by integrally molding a power supply part 70 with a detection part 71 is fitted out of the image forming area of the photosensitive drum 21. And the toner supplied to the drum 21 is made to adhere to the detection part 71. Then a light beam from a light emission diode is radiated onto the detection part 71 and the reflected light is received by a photodiode so as to detect the density of the toner by converting the variation of a light receiving quantity into a voltage. Thus it is unnecessary to turnably mount the probe 45 and a special driving mechanism is not necessitated. Since the probe 45 is provided on the end part of the drum 21 opposite to the toner replenishing port of a developing unit 56, toner detecting speed becomes high and the detection becomes accurate. |
