Pedro F Engel

US Patent:

43694551, Jan 18, 1983

Filed:

Dec 8, 1980

Appl. No.:

6/214149

Inventors:

Charles H. McConica - Fort Collins CO
Michael A. Tremblay - Loveland CO
Pedro F. Engel - Fort Collins CO

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

G01D 1516

US Classification:

346140R

Abstract:

The electrical drive pulse applied to the piezoelectric crystal of an ink jet printer is designed to cause ejection of a single desired ink droplet from the print head and to preclude ejection of unwanted multiple ink droplets. The drive pulse consists of the superposition of two waveforms wherein the first waveform causes ejection of the desired ink droplet and the superimposed second waveform removes energy from the print head so that mechanical ringing of the ink supply within the print head does not cause ejection of unwanted ink droplets.

US Patent:

43475248, Aug 31, 1982

Filed:

Aug 7, 1980

Appl. No.:

6/175991

Inventors:

Pedro F. Engel - Fort Collins CO
Phillip A. McCollum - Loveland CO

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

G01D 1518

US Classification:

346140R

Abstract:

A piezoelectrically driven ink jet printer includes a shock absorbing mechanism positioned in the ink supply tube for minimizing the effects on the ink within the print head of physical shocks to the ink supply tube or ink supply cartridge. The shock absorbing mechanism includes a flow restriction device and a reservoir device arranged such that the physical performance of the shock absorbing mechanism is analogous to the electrical performance of an RC low pass filter.