| 摘要 |
The present invention is a charging apparatus capable of electrically tuning or altering, on a relatively local scale, the corona ion current passing between a corona producing device and a charge retentive surface. The charging apparatus, which may be either a corotron or a scorotron, is specifically adapted to apply a uniform charge to a charge retentive surface which characteristically exhibits non-uniform charging behavior. More specifically, the charging apparatus comprises corona producing devices, spaced apart from the charge retentive surface, for emitting a corona ion current, and device, responsive to a bias voltage, for locally altering the corona ion current passing between said corona producing device and the charge retentive surface. In the described embodiments, the ion current altering device includes segmented grids, segmented shields and segmented electrodes, all of which may be maintained at variable bias voltages to produce local variation in the ion current passing to the charge retentive surface.
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