| 摘要 |
PURPOSE:To hold the charged potential on an image holding body at a constant value by connecting a variable resistance between an ionic current control member and a ground, detecting a difference between the voltage applied to the ionic current control member and the variable set voltage by an error amplifier, and applying it to a variable resistance element. CONSTITUTION:In an example applied to a device for negative charging, voltage VG is divided and detected by resistances R1, R2 connected between a grid 3 of a scorotron 2 and a ground, and a difference between said voltage and set voltage VS is amplified and applied to the base of a transistor (TR), by which the voltage VG applied to the grid 3 is held at a constant value. Accordingly, the VG can be varied by changing the set voltage VS. As a result, this device is very convenient for making the charged potential variable basing on various conditions, and accordingly, the voltage applied to an ionic current control member is kept constant in accordance with the set voltage, and the charged potential on an image holding body can be held at a constant value, by a simple constitution. |
