| 摘要 |
PURPOSE:To rotate a detection probe with the rotation of a photosensitive drum by providing the detection probe on one end part of the photosensitive drum. CONSTITUTION:The detection probe 45 obtained by integrally molding a power supply part 70 with a detection part 71 with synthetic resin is fitted on the one end part of the photosensitive drum 21, that is, out of the image forming area of the drum 21. The probe 45 is electrically insulated from the drum 21, and it is desirable that chromium is deposited in vacuum or in sputtering on its surface. And toner supplied to the drum 21 is made to adhere to the detection part 71. A light beam from a light emission diode 48a is radiated onto the detection part 71 and the reflected light is received by a photodiode 48b, then the variation of light receiving quantity is converted into a voltage so as to detect the density of the toner. When the density of the toner lowers, the toner is replenished and mixed by a mixer to be supplied to a developing roller. |
