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Feedback for Synchronized Pressure Jet Using Optical Sensor

IP.com Disclosure Number: IPCOM000081294D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Chen, WH: AUTHOR [+3]

Abstract

An ink jet system shown schematically in Fig. 1 utilizes a nozzle 10 to which ink is supplied under pressure. A piezoelectric ceramic 12 applies perturbations to the ink stream for forming drops. A charging electrode 14 charges the drops in accordance with applied signal voltages, and deflection plates 16 provide a field for deflecting unwanted drops to a gutter 18 and utilization drops to print on a paper 20.

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Feedback for Synchronized Pressure Jet Using Optical Sensor

An ink jet system shown schematically in Fig. 1 utilizes a nozzle 10 to which ink is supplied under pressure. A piezoelectric ceramic 12 applies perturbations to the ink stream for forming drops.

A charging electrode 14 charges the drops in accordance with applied signal voltages, and deflection plates 16 provide a field for deflecting unwanted drops to a gutter 18 and utilization drops to print on a paper 20.

As shown in Figs. 2 and 3 an optical sensor 22 may be positioned to sense nonprinting drops which may be charged by a predetermined sawtooth or square wave. The sensor may comprise a light source 24, lenses 26a-b, and slit 28 arrangement such as shown in Figs. 4 and 5.

The light sensor 22 is set so that the image of the ink stream in a particular position is focused on the slit 28. If the charging process is synchronized, the phototransducer will be activated indicating printing conditions are correct. If the transducer detects no drop presence, the feedback circuit operates to change the phase of the transducer and charging voltage. Fig. 6 shows a flow diagram explaining the system operation. Fig. 7 shows the relationship between drop formation and the calibrating signal.

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