摘要 |
A corona charging device including a dielectric-coated elongate conductor (11) contacting or closely spaced from a control electrode. In the first version of this device, the control electrode comprises a conductive grid (17), which is mounted against an insulating support (15). In a second version, the control electrode consists of a slotted conductor (94), with the dielectric-coated elongate conductor (11) embedded in the slot (96). A high voltage varying potential (25) between the elongate conductor (11) and control electrode induces a glow discharge in an air region in proximity to the two conductors. The control electrode may act as a grounding member to provide a corona discharge device with respect to a proximate surface (20). Alternatively, the control electrode may be maintained at a desired potential (27) to provide a charging device with an automatically limited voltage. The corona charging devices of the invention are characterized by a linear relationship between output ion currents and a direct current extraction potential. In further versions of the second corona device, the slotted conductor and dielectric-coated conductor may be replaced with alternative structures which provide an equivalent enclosure. |