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Driving Pressure Wave Shape for Drop Ejector

IP.com Disclosure Number: IPCOM000062551D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Drago, GA: AUTHOR [+2]

Abstract

The drive signal in a drop-on-demand ink jet printer is selected to provide the optimum pressure wave in the fluid channel that leads to the nozzle. The active element in the channel is a piezoelectric tube which changes diameter when excited by the drive signal. Reflections from the reservoir end of the channel are minimized by an energy dissipative screen. The drive signal produces a pressure wave designed to accelerate a column of ink out the nozzle, break off the column of ink to form a drop, and draw the remaining ink back into the channel through the nozzle without also drawing air into the channel. The drop ejector is shown in Fig. 1. Piezoelectric tube 10 contains an active region 12 having a length L. When the drive signal in Fig. 2A is applied to this active region, the pressure wave in Fig.

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Driving Pressure Wave Shape for Drop Ejector

The drive signal in a drop-on-demand ink jet printer is selected to provide the optimum pressure wave in the fluid channel that leads to the nozzle. The active element in the channel is a piezoelectric tube which changes diameter when excited by the drive signal. Reflections from the reservoir end of the channel are minimized by an energy dissipative screen. The drive signal produces a pressure wave designed to accelerate a column of ink out the nozzle, break off the column of ink to form a drop, and draw the remaining ink back into the channel through the nozzle without also drawing air into the channel. The drop ejector is shown in Fig. 1. Piezoelectric tube 10 contains an active region 12 having a length L. When the drive signal in Fig. 2A is applied to this active region, the pressure wave in Fig. 2C moves forward in channel 20 to the nozzle plate 14 and rearward in the channel to the dissipative screen 16. Screen 16 absorbs the rear pressure wave so that it does not reflect from the interface between tube 10 and ink reservoir 18. Therefore, when selecting the wave shape for optimum drop ejection, the rearward traveling wave may be ignored. After a drop is ejected, ink flows through screen 16 into the channel 20 to replace the ejected ink.

(Image Omitted)

The pressure wave in Fig. 2C may be derived from the drive signal in Fig. 2A by superimposing the drive signal with its negative counterpart delayed by the time i...