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Noncontinuous DITHER Excitation of Drop-On-Demand Ink Jet Printer

IP.com Disclosure Number: IPCOM000042981D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Moss, JD: AUTHOR

Abstract

In conventional methods of drop-on-demand ink jet printing, there is a problem of film build-up on the nozzle which causes the nozzle to stop ejecting ink drops. This article describes noncontinuous dithering or agitation of ink in a ink drop ejector when the ejector is not energized to eject drops. Dithering consists of exciting the drive crystal of the ejector with a low-amplitude cyclic signal. This causes the meniscus at the nozzle of the ejector to oscillate; however, no drops are ejected. Dithering only begins just prior to the start of a print operation by the drop-on-demand ejector. Logic to provide the drive signal for the crystal in the ejector is shown in Fig. 1. Fig. 2 shows signals that exist at the input and the output of the logic. Drive pulses are applied to data AND gate 10 and dither AND gate 12.

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Noncontinuous DITHER Excitation of Drop-On-Demand Ink Jet Printer

In conventional methods of drop-on-demand ink jet printing, there is a problem of film build-up on the nozzle which causes the nozzle to stop ejecting ink drops. This article describes noncontinuous dithering or agitation of ink in a ink drop ejector when the ejector is not energized to eject drops. Dithering consists of exciting the drive crystal of the ejector with a low-amplitude cyclic signal. This causes the meniscus at the nozzle of the ejector to oscillate; however, no drops are ejected. Dithering only begins just prior to the start of a print operation by the drop-on-demand ejector. Logic to provide the drive signal for the crystal in the ejector is shown in Fig. 1. Fig. 2 shows signals that exist at the input and the output of the logic. Drive pulses are applied to data AND gate 10 and dither AND gate 12. When a data pulse is present at gate 10, a drive pulse is passed to high voltage driver 14. When a DITHER ON signal is present at gate 12, drive pulses are passed to low voltage driver 16. Low voltage driver 16 applies low voltage pulses to ejector crystal 18 through diode 20. These low voltage pulses cause the meniscus at the nozzle to oscillate, but a drop is not ejected. High voltage driver 14 applies a high voltage pulse to ejector crystal 18. When the high voltage drive pulse is present, diode 20 is reverse biased. A high voltage drive pulse causes the ejector to eject a drop. The DI...