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Drop On Demand Ink Jet Printing Head

IP.com Disclosure Number: IPCOM000053133D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Simpson, HW: AUTHOR

Abstract

In typical drop-on-demand printer heads, the excitation of a piezoelectric crystal, which forms one wall of the head, causes a decrease in the volume of a chamber, forcing an ink droplet out of an orifice or nozzle end of the head. In this manner, each excitation produces one drop. Typically, however, the chamber in which the piezoelectric crystal resides requires some kind of rear impedance to fluid flow from the ink supply because as the piezoelectric crystal excites the fluid within the chamber, ink is forced towards the ink supply line as well as out the nozzle. A rear impedance device is illustrated in the drawing.

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Drop On Demand Ink Jet Printing Head

In typical drop-on-demand printer heads, the excitation of a piezoelectric crystal, which forms one wall of the head, causes a decrease in the volume of a chamber, forcing an ink droplet out of an orifice or nozzle end of the head. In this manner, each excitation produces one drop. Typically, however, the chamber in which the piezoelectric crystal resides requires some kind of rear impedance to fluid flow from the ink supply because as the piezoelectric crystal excites the fluid within the chamber, ink is forced towards the ink supply line as well as out the nozzle. A rear impedance device is illustrated in the drawing.

Referring now to the drawing, a typical drop-on-demand head 10, including a chamber 11 normally filled with ink, is illustrated therein. An ink supply conduit 12 feeds the chamber 11 such that when a crystal 13 is perturbated, a drop will be ejected from the nozzle 14. As the crystal decreases the size of the chamber 11, to eject a droplet 15 from the nozzle, there is a pressure increase within the chamber which forces a ball 16 to move to the left to partially seal the inlet conduit 12. As the crystal 13 returns to its home position, pressure is reduced within the chamber 11, causing the pressure of the ink supply in conduit 12 to effect movement of the ball slightly to the right in the chamber, allowing ink replacement of the amount of ink ejected from the chamber on the last crystal perturbation.

As illustra...