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OVERCOATED INK JET DROPLET EXCITATION ELECTRODE

IP.com Disclosure Number: IPCOM000024912D
Original Publication Date: 1982-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 70K

Publishing Venue

Xerox Disclosure Journal

Abstract

In one form of synchronous or Rayleigh-type ink jet printing, ink droplet production is induced by an alternating electromagnetic field produced in the vicinity of an ink column by an excitation electrode. Electrical breakdown between the electro-hydrodynamic electrode and other parts of the printhead is a critical concern since such an occurrence can result in permanent damage to the printhead. It is proposed that spark failures be avoided by overcoating the electrode with a thin layer of moderately insulating material. The resistivity of the overcoating is chosen to provide a relaxation time of between .01 and 10 seconds, which will allow charge built up on the electrode to dissipate and therefore avoid electrical breakdown and damage to the printhead structure. A suitable coating must be compatible with the ink and might suitably come from the group of materials including parylene, fluotopolymers, glass and silicone dioxide.

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XEROX DISCLOSURE JOURNAL

OVERCOATED INK JET DROPLET EXCITATION ELECTRODE
Ivan Rezanka
Richard Kellerman

Proposed Classification
U.S. Cl. 346/75

Int. C1. Gold 15/18

In one form of synchronous or Rayleigh-type ink jet printing, ink droplet production is induced by an alternating electromagnetic field produced in the vicinity of an ink column by an excitation electrode. Electrical breakdown between the electro- hydrodynamic electrode and other parts of the printhead is a critical concern since such an occurrence can result in permanent damage to the printhead. It is proposed that spark failures be avoided by overcoating the electrode with a thin layer of moderately insulating material. The resistivity of the overcoating is chosen to provide a relaxation time of between .01 and 10 seconds, which will allow charge built up on the electrode to dissipate and therefore avoid electrical breakdown and damage to the printhead structure. A suitable coating must be compatible with the ink and might suitably come from the group of materials including parylene, fluotopolymers, glass and silicone dioxide.

In a typical arrangement, a dielectric spacer is used to mount the electrode in close proximity to the ink jet column. As an alternative coating technique, both the electrode and the spacer can be overcoated with the ink compatible material. If the coating is accomplished in a pinhole-free fashion, the electrode and spacer materials need not be ink resistants thus permitting a...