Advanced Color Technology, Inc.

Steven I Zoltan

David M Hudson

Peter L Duffield

A mechanically balanced pulsed ink droplet mechanism includes a disk or ring of piezoelectric ceramic material positioned within a metal ring of rectangular cross section having an annular channel in its inner surface that is sealed by a thin metal diaphragm to form an annular ink chamber. The piezoelectric transducer is in mechanical engagement with the inner surface of the annular diaphragm, but the ink is electrically insulated from the ceramic. A voltage pulse applied to opposite sides of the disk causes it to expand and eject a droplet of ink from the printing orifice. The ink chamber is shallow and has a ratio of cross section to wetted perimeter or hydraulic radius approximately equal to the diameter of the orifice which quickly damps oscillations resulting from the ejection of each droplet of ink and permitting higher speed operation. The ink chamber is sealed without the use of compliant materials resulting in minimal additional compliance to the liquid. The construction causes the displacement produced by the transducer to be efficiently transmitted to the ink chamber, producing droplets with improved definition at greater efficiencies.

Printing head for ink jet printer

The method of making a print head of the type that includes a piezoelectric transducer positioned within a metal housing having an annular channel in its inner surface that is sealed by a thin metal diaphragm to form an annular ink chamber. The transducer is in mechanical engagement with the inner surface of the diaphragm. The sudden removal of a voltage applied to the transducer expands the disk to reduce the volume of the ink chamber, rupture the meniscus, and force a droplet of ink from the printing orifice. The housing is formed with an internal taper which permits a groove to be cut readily either by a casting or by a tool entering from the larger end of the central opening in the housing. An aluminum mandrel is tapered to match the taper on the inner surface of the housing and provided with an annular groove that corresponds to the groove in the housing. The mandrel is plated with nickel that will later form the diaphragm. The housing and mandrel are then plated with indium. The mandrel is then forced into the central opening of the housing and subjected to ultrasonic energy, or maintained under pressure at an elevated temperature, to form a cold weld. The mandrel is removed by dissolving it in a caustic solution.

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Brookfield, CT, United States of America

Steven I Zoltan