| 摘要 |
PURPOSE:To constitute an apparatus in a tightly closed structure and to eliminate the need of special consideration at the built-in time of a copying device, by detecting electric potential of the surface to be detected by an electric signal basing on the change of capacity of a capacitor caused by the change of distance between electrodes. CONSTITUTION:A line of electric force from a high potential surface 1 is given to a current collecting electrode 2 by applying high voltage to the surface 1 to be detected and an electric charge being equal to that generating in the electrode 2 is accumulated between capacitor electrodes 3, 4. Further, an electric charge is charged and discharged by the change of capacity by varying the distance between the electrodes 3, 4, that is, the capacity by vibrating the electrodes 3, 4 by driving a piezo-electric tuning fork 7 and an electric signal basing on it is given to an FET and detected voltage is fetched out of this FET. A toner etc. is not invaded into a case and the special consideration is unnecessary at the built-in time of a copying device in such surface electric potential detecting apparatus because the apparatus is constituted by a tightly closed structure. |
