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Ink Drop Velocity Measurement by Drop Fluorescence

IP.com Disclosure Number: IPCOM000083055D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Kuhn, L: AUTHOR [+4]

Abstract

In order to measure drop velocity of a given ink drop by measuring its transit time across a fixed distance, the given drop must be marked to distinguish it from neighboring drops. It is desirable to use a moderately long distance for the fixed distance so that a relatively accurate determination of the velocity, that is the transit time, may be made without resorting to high-speed electronics. For instance, if the fixed distance is 1 cm and the drop velocity is 2000 cm/sec, the transit time is 1/2 ms. Determination of a 1% velocity variation may be measured by measuring a time difference of 5 mu s.

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Ink Drop Velocity Measurement by Drop Fluorescence

In order to measure drop velocity of a given ink drop by measuring its transit time across a fixed distance, the given drop must be marked to distinguish it from neighboring drops. It is desirable to use a moderately long distance for the fixed distance so that a relatively accurate determination of the velocity, that is the transit time, may be made without resorting to high-speed electronics. For instance, if the fixed distance is 1 cm and the drop velocity is 2000 cm/sec, the transit time is 1/2 ms. Determination of a 1% velocity variation may be measured by measuring a time difference of 5 mu s.

With reference to the figure, a stream of ink 2 has a fluorescent dye introduced therein, such that a drop of ink fluoresces when illuminated by light. The fluorescence must persist for a time on the order of 1 ms, to be detected between two points downstream along an ink droplet flight path. A light-emitting diode 4 illuminates a droplet of ink 6, which is then detected by a light detecting device 8 at a first point along the droplet path. A second light detecting device 10 situated at a distance L from the first detector 8, is used to detect the drop 6 as it fluoresces when passing the detector 10.

The velocity Vd is measured by electronically determining the time T required for the fluorescent drop to travel the distance L between the detectors 8 and 10. The velocity is determined in accordance with the equation Vd...