Abstract: The invention provides a support member which carries at least one axially aligned corona electrode, and a conductive biasing member wrapped around both the support member and the electrode. The biasing member is preferably a wire wrapped about the support and electrode to form a coil and preferably there are four electrodes. A conductor extends the length of the coil to ensure continuity should the biasing member fail locally.

Abstract: A corona charging device including a dielectric-coated elongate conductor contacting or closely spaced from a grid electrode, mounted against an insulating support. A high voltage varying potential between the elongate conductor and grid electrode induces a glow discharge in the vicinity of the dielectric-coated electrode. The grid electrode may act as a ground plane to provide a corona discharge device with respect to a proximate member. Alternatively, the grid electrode may be maintained at a desired potential to provide a charging device with an automatically limited voltage.

Abstract: A corona charging device including a dielectric-coated elongate conductor embedded in a slot in a conductive member. A high voltage varying potential between the elongate conductor and slotted conductive member induces a glow discharge in a region of proximity of the two conductors. The slotted conductor may act as a grounding member to provide a corona discharge device with respect to a proximate surface. Alternately, the slotted conductor may be maintained at a desired potential to provide a charging device with an automatically limited voltage. The slotted conductor and dielectric-coated conductor may be replaced with alternative structures which provide an equivalent enclosure.

Abstract: A corona charging device including a dielectric-coated elongate conductor contacting or closely spaced from a grid electrode, mounted against an insulating support. A high voltage varying potential between the elongate conductor and grid electrode induces a glow discharge in the vicinity of the dielectric-coated electrode. The grid electrode may act as a ground plane to provide a corona discharge device with respect to a proximate member. Alternatively, the grid electrode may be maintained at a desired potential to provide a charging device with an automatically limited voltage.