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CONTINUOUS STREAM TYPE INK JET ARRAY WITH CALIBRATION INK STREAMS

IP.com Disclosure Number: IPCOM000025763D
Original Publication Date: 1987-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 107K

Publishing Venue

Xerox Disclosure Journal

Abstract

In the continuous stream ink jet array technology, the use of high voltage deflection fields for substantial droplet deflection is required to calibrate the ink stream array after ink stream start-up from a cold or prolonged shut down condition. Due to temperature and ink property variations coupled with long term droplet generator drift, several reliability problems are encountered with the initial stream operation, whenever substantial droplet deflections are required in order to use a calibration droplet sensor after each ink jet array start-up from a cold start condition. For example, (1) the high voltage deflection plates are usually contaminated by an excessively long breakoff length or satellite droplet merging distance; (2) a stream break-up point upstream of the charge tunnels cause a loss of droplet chargeability; and (3) wide range of stream deflection sensitivity (i.e., droplet deflection per unit charging amplifier voltage) causes difficulty in formulating a reliable ink stream calibration strategy.

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Page 1 of 2

XEROX DISCLOSURE JOURNAL

CONTINUOUS STREAM TYPE INK JET ARRAY WITH CALIBRATION INK STREAMS Int. C1. Gold 15/18 Chein-Hwa S. Tsao
Norman J. Bergman

Proposed Classification
U.S. C1.346/75

12

,

CAL 14- 14 JET CAL A

DROPGEN./APERTURES

JET 8

A

10

-

/ .....

JET 138 1

20 16 v

PRINT JETS

I 785 MIL

I

,- 18

26

In the continuous stream ink jet array technology, the use of high voltage deflection fields for substantial droplet deflection is required to calibrate the ink stream array after ink stream start-up from a cold or prolonged shut down condition. Due to temperature and ink property variations coupled with long term droplet generator drift, several reliability problems are encountered with the initial stream operation, whenever substantial droplet deflections are required in order to use a calibration droplet sensor after each ink jet array start-up from a cold start condition. For example, (1) the high voltage deflection plates are usually contaminated by an excessively long breakoff length or satellite droplet merging distance; (2) a stream break-up point upstream of the charge tunnels cause a loss of droplet chargeability; and (3) wide range of stream deflection sensitivity (i.e., droplet deflection per unit charging amplifier voltage) causes difficulty in formulating a reliable ink stream calibration strategy.

To circumvent the above anticipated difficulties, the addition of extra calibration ink streams just to measure and control stream velocity and break-up point without using high voltage deflection field is shown in the accompanying figure.

Volume 12 Number 6 November/December 1987 265

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CONTINUOUS STREAM TYPE INK JET ARRAY WITH CALIBRATION INK STREAMS (Cont'd)

This figure is a partially shown schem...