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INK TEMPERATURE CONTROL FOR CONTINUOUS INK JET USING THIN FILM RESISTORS

IP.com Disclosure Number: IPCOM000025828D
Original Publication Date: 1988-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 139K

Publishing Venue

Xerox Disclosure Journal

Abstract

In continuous ink jet printing systems, temperature fluctuations in the ink are of major importance, since the viscosity and surface tension of water-based fluids are a function of the temperature. For example, the surface tension of water varies from 0.074 N/m at 20°C to 0.059 N/m at 100°C; the viscosity changes from 1.00 centipoise at 20°C to 0.22 centipoise at 100°C. Viscosity and surface tension are critical variables for jet breakoff length and drop generation, so it is generally perceived that the ink temperature should be controlled to some degree.

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Page 1 of 4

(EROX DISCLOSURE JOURNAL

INK TEMPERATURE CONTROL FOR Classification Proposed CONTINUOUS INK JET USING THIN

U.S. C1.346/75

FILM RESISTORS
Int. Donald J. Drake C1. Gold 15/18

13 11 15

FIG. 1

24 23

/ Z2LX-4 11

Volume 13 Number 3 May/June 1988 127

FIG. 2

[This page contains 1 picture or other non-text object]

Page 2 of 4

INK TEMPERATURE CONTROL FOR CONTINUOUS INK JET USING THIN FILM RESISTORS (Cont'd)

In continuous ink jet printing systems, temperature fluctuations in the ink are of major importance, since the viscosity and surface tension of water-based fluids are a function of the temperature. For example, the surface tension of water varies from 0.074 N/m at 20°C to 0.059 N/m at 100°C; the viscosity changes from 1.00 centipoise at 20°C to 0.22 centipoise at 100°C. Viscosity and surface tension are critical variables for jet breakoff length and drop generation, so it is generally perceived that the ink temperature should be controlled to some degree.

U.S. Patent 4,638,328 describes a continuous thermal ink jet printhead comprising an etched silicon channel plate and a heater plate having resistors fabricated by standard integrated circuit processes. This printhead may be improved by the use of additional warm-up resistors whose purpose is to heat the ink in the printhead to some desired temperature, and, by making use of the change of resistor resistance with the temperature change, the use of still additional resistors whose purpose is to monitor the temperature of the ink and thereby permit a control system to stabilize the ink temperature via power modulation to the warm-up resistors.

Figure 1 is a typical cross-sectional view of an improved continuous thermal ink jet printhead 10 of the type described in the above-mentioned U.S. patent comprising an etched silicon channel plate 12 having a fill hole 13, reservoir 11, and a plurality of ink channels 15. The channel plate 15 is aligned and bonded to a heater plate 14 having a plurality of resistors 16, one for each channel. Resistors 16 perturbate the pressurized ink (not shown) which exits the nozzles 18 as ink streams. The perturbation causes the ink streams to break up into droplets (not shown) a fixed distance f...