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METHOD AND APPARATUS FOR INCREASING CORONA EFFICIENCY IN AN IONOGRAPHIC IMAGING DEVICE

IP.com Disclosure Number: IPCOM000026014D
Original Publication Date: 1989-Oct-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 107K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an ionographic device including an ionographic printing head exemplified by US-A 4,644,373 to Sheridon et al., projecting a modulated stream of ions in imagewise fashion towards a moving imaging surface, wherein the head is provided with an ion chamber supporting a coronode held at a voltage VC to produce ions for deposit on an imaging surface and a modulation channel extending from the ion chamber towards the imaging surface through which a stream of ions is directed for imagewise modulation by a plurality of modulation electrodes, electric field distribution within the ion chamber is controlled by selectively biasing regions of the head structure that form the chamber at different voltage levels, in an arrangement causing the focusing of ion density in the area of the ion chamber adjacent to the modulation channel. When ions are entrained for movement through the modulation channel, the increased ion density in the area adjacent to modulation channel increases the effective corona current output of the printing head without requiring increased airflow or displacement of the coronode from the optimum corona producing location. Desirably, the head regions are selectively biased along the desired path of ions through the ion chamber so that ions flowing from the coronode pass though successively lower voltages from the coronode to the modulation channel.

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KEROX DISCLOSURE JOURNAL

METHOD AND APPARATUS FOR INCREASING CORONA EFFICIENCY U.S. C1.346/158 IN AN IONOGRAPHIC IMAGING
DEVICE
Oscar G. Hauser
Robert W. Anderson
Lawrence M. Hart

Proposed Classification

Int. C1. Gold 15/06

In an ionographic device including an ionographic printing head exemplified by US-A 4,644,373 to Sheridon et al., projecting a modulated stream of ions in imagewise fashion towards a moving imaging surface, wherein the head is provided with an ion chamber supporting a coronode held at a voltage VC to produce ions for deposit on an imaging surface and a modulation channel extending from the ion chamber towards the imaging surface through which a stream of ions is directed for imagewise modulation by a plurality of modulation electrodes, electric field distribution within the ion chamber is controlled by selectively biasing regions of the head structure that form the chamber at different voltage levels, in an arrangement causing the focusing of ion density in the area of the ion chamber adjacent to the modulation channel. When ions are entrained for movement through the modulation channel, the increased ion density in the area adjacent to modulation channel increases the effective corona current output of the printing head without requiring increased airflow or displacement of the coronode from the optimum corona producing location. Desirably, the head regions are selectively biased along the desired path of ions through the ion chamber so that ions flowing from the coronode pass though successively lower voltages from the coronode to the modulation channel.

In a first embodiment of the invention, the head structure is divided into plural segments, each segment electrically insulated from the adjacent and biased with a voltage source appropriate for the biasing scheme. In a second e...