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Ink Jet Nozzle Pressure Measurement Circuit

IP.com Disclosure Number: IPCOM000052383D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Aukschun, RA: AUTHOR [+2]

Abstract

In failure diagnosis of nonimpact printers, such as ink jet printers, is often helpful if the ink pressure in the nozzle is known as a function of time. In IBM Technical Disclosure Bulletin 21, 4925-4927 (May 1979), there is disclosed an ink jet nozzle pressure measurement system to achieve such a function. The circuit presented in the drawing is a simplification of the system illustrated in the aforementioned reference.

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Ink Jet Nozzle Pressure Measurement Circuit

In failure diagnosis of nonimpact printers, such as ink jet printers, is often helpful if the ink pressure in the nozzle is known as a function of time. In IBM Technical Disclosure Bulletin 21, 4925-4927 (May 1979), there is disclosed an ink jet nozzle pressure measurement system to achieve such a function. The circuit presented in the drawing is a simplification of the system illustrated in the aforementioned reference.

Turning now to the drawing, in a continuous-type or "Sweet" ink jet printer the piezoelectric crystal 10 is conventionally utilized to perturbate the ink supply within the head to facilitate drop break-off from the ink stream being projected from the ink jet nozzle. Typically, the piezoelectric crystal 10 is oscillated as by a crystal drive 11, and by switching the crystal from the crystal drive to a high impedance charge amplifier 12 as through an analog switch 13, the crystal may then act as a pressure transducer giving an indication of whether the pressure is increasing or decreasing within the head of the printer.

When the pressure in the head changes, the crystal 10 is deflected, which causes the charge to accumulate on the crystal. This increase in charge is amplified by the charge amplifier 12, the output of which is fed to a pair of operational amplifiers 14 and 15, respectively. The operational amplifier 14 is an inverting amplifier, while the operational amplifier 15 is not. The inverting ampl...