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Ink Jet Velocity Error Compensation

IP.com Disclosure Number: IPCOM000084528D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Lominac, HR: AUTHOR

Abstract

In multiple nozzle ink jet printers having nozzles fabricated in silicon wafers 31 with square holes 32, the jet velocity increases as the hole size increases. The faster drops reach the paper sooner than the slower drops, and when the paper is moving, this causes a print registration error. At the same time, the drop breakoff length also increases as the hole size increases which shortens the distance to the paper, which makes the registration error even greater. It is possible to make the drop breakoff length shorter with larger size holes, thus compensating for the velocity error. This will be exact if the breakoff length is short enough to make the time for all drops to reach the paper the same.

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Ink Jet Velocity Error Compensation

In multiple nozzle ink jet printers having nozzles fabricated in silicon wafers 31 with square holes 32, the jet velocity increases as the hole size increases. The faster drops reach the paper sooner than the slower drops, and when the paper is moving, this causes a print registration error. At the same time, the drop breakoff length also increases as the hole size increases which shortens the distance to the paper, which makes the registration error even greater. It is possible to make the drop breakoff length shorter with larger size holes, thus compensating for the velocity error. This will be exact if the breakoff length is short enough to make the time for all drops to reach the paper the same.

The ink jet may be perturbated by electrohydrodynamic means. It comprises an electrode 33 mounted on the nozzle plate 31 which surrounds the nozzles 32. An AC voltage applied at 34 to the electrode 33 perturbs the jet, causing it to break up in synchronism with the driving voltage. This method is more effective if the electrode 33 is closer to the jet stream. The drop breakoff distance decreases as the jet to electrode distance decreases.

Now if these electrodes 33 are optimally placed around each nozzle 32 at the proper distance, all jet breakoff distances will be the same for the same nozzle sizes. A larger nozzle size will place the jet closer to the electrode 33 which will be more efficient, and the drop breakoff length will be...