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Induced Charge Compensation for Ink Jet Heads

IP.com Disclosure Number: IPCOM000088518D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Albrecht, DW: AUTHOR

Abstract

A multistream ink jet system is shown in which charged drops are deflected to the gutter and uncharged drops are used to print.

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Induced Charge Compensation for Ink Jet Heads

A multistream ink jet system is shown in which charged drops are deflected to the gutter and uncharged drops are used to print.

Drops 10 are produced in a plurality of streams moving into the paper and the drops are selectively charged by drivers 12, placing the voltage from source 14 on the associated charge electrode 16 at the time of drop breakoff. The first drop following a charged drop can have a significant induced charge of the opposite polarity to the charge of the guttered drops, and this induced charge causes misregistration of that drop and, therefore, degraded print quality.

A bias electrode 18 is positioned opposite the charge electrodes, and a charge is produced on all ink drops by the bias source 20 at the beginning of each print cycle for the duration of one drop cycle. The bias source is of magnitude and sign so that the induced charge is cancelled on all drops to be used to print. Should a particular driver charge the drops to not print, the bias signal would add a small amount of charge to the first drop, and it would be deflected an extra amount.

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