Browse Prior Art Database

BINARY CONTINUOUS THERMAL INK JET BREAK OFF LENGTH MODULATION

IP.com Disclosure Number: IPCOM000025964D
Original Publication Date: 1989-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 6 page(s) / 241K

Publishing Venue

Xerox Disclosure Journal

Abstract

In Figure 1, a basic continuous stream type ink jet system 10 is shown. Droplet generator 12 has apertures or nozzles 14 which emit continuous pressurized streams 16 of ink from a cavity (not shown) within the droplet generator. A pressure perturbation (typically formed from a single piezoelectric transducer, not shown) breaks up the continuous ink streams into ink droplets 18 a predetermined distance downstream from the nozzles. Prior to break off, the ink streams are individually charged to various levels by an array of discrete charge tunnels 20. When the droplets break off from the streams, they are charged. These charged droplets are then deflected by varying degrees depending on the droplet charge by a deflection plate 22 common to all of the droplet streams.

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Page 1 of 6

XEROX DISCLOSURE JOURNAL

BINARY CONTINUOUS THERMAL Proposed Classification INK JET BREAK OFF LENGTH
MODULATION Int.
C1. Gold 15/18 Donald J. Drake

US. C1.346175

12

22

FIG. 1

i'

22

FIG. 2

Volume 14 Number 3 May/June 1989 95

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Page 2 of 6

BINARY CONTINUOUS THERMAL INK JET BREAK OFF LENGTH MODULATION (Cont'd)

16

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I-AI

16

18

b

96 XEROX DISCLOSURE JOURNAL

Volume 14 Number 3 May/June 1989

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

Page 3 of 6

BINARY CONTINUOUS THERMAL INK JET BREAK OFF LENGTH MODULATION (Cont'd)

t

FIG. 5

28

6 FIG. I I

 XEROX DISCLOSURE JOURNAL Volume 14 Number 3 May/June 1989 97

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

Page 4 of 6

BINARY CONTINUOUS THERMAL INK JET BREAK OFF LENGTH MODULATION (Cont'd)

In Figure 1, a basic continuous stream type ink jet system 10 is shown. Droplet generator 12 has apertures or nozzles 14 which emit continuous pressurized streams 16 of ink from a cavity (not shown) within the droplet generator. A pressure perturbation (typically formed from a single piezoelectric transducer, not shown) breaks up the continuous ink streams into ink droplets 18 a predetermined distance downstream from the nozzles. Prior to break off, the ink streams are individually charged to various levels by an array of discrete charge tunnels 20. When the droplets break off from the streams, they are charged. These charged droplets are then deflected by varying degrees depending on the droplet charge by a deflection plate 22 common to all of the droplet streams.

U.S. Patent 4,638,328 to Drake et a1 describes the use of thermal pulses in stably breaking up individual ink streams using thin film resistors in each channel. This architecture allows a novel method of binary continuous ink jet printing.

The basic princi le of this new binary printing method is a modulation of ink

. resistor. The break off length can be easily changed by one wavelength distance. Referring to Figure 2, if a charge plate 22 is placed at the furthest

BOL, it will induce some level of charge In the droplet 18 breaking offf. However, if the resistor 24 is given a more powerful heater pulse, the break off length will decrease, and the droplet will break off some greater distance from the charge electrode and receive much less charge. If both heavily charged and lightly charged droplets are exposed to deflection plates or even a ground plane (neither shown), the heavily charged droplet will deflect much more and can be directed to a gutter (not show!.) while the lightly charged drop will hit the recording medium (not shown).

In somewhat more detail, a simplified equivalent electrical circuit is shown in Figure 3. For the purposes of illustration, the jet diameter (dj) is assumed to be 1 mil, the Mdj ratio is assumed to be 7 and the minimum nominal distance from the charge electrode 22 to the jet 16 (dell is assumed to be 1 mil. The distance de is del when the weaker heat...