Browse Prior Art Database

Nozzle Cleaning Process

IP.com Disclosure Number: IPCOM000088739D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 58K

Publishing Venue

IBM

Related People

Seitz, HK: AUTHOR

Abstract

The directionality of a magnetic ink stream is extremely sensitive to changing conditions at the interface of the ink stream and the outer surface of the nozzle, i.e., a particle of only a few mu in size can deflect the stream by >1 millirad. It is, therefore, important to keep the exit side of the nozzle clean after a start-up to prevent ink particles from drying.

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Nozzle Cleaning Process

The directionality of a magnetic ink stream is extremely sensitive to changing conditions at the interface of the ink stream and the outer surface of the nozzle,
i.e., a particle of only a few mu in size can deflect the stream by >1 millirad. It is, therefore, important to keep the exit side of the nozzle clean after a start-up to prevent ink particles from drying.

An efficient nozzle cleaning process is illustrated in Figs. 1 and 2. Before start, a nozzle 1 is covered with an air-tight cover 3 placed on the nozzle after the previous shutdown rotating valve 2 in position 1. The space between the cover and the nozzle is filled with ink or with any other compatible fluid. Ink is cheaper and provides reproducible start-up condition. Low viscosity fluids would mix with the ink and result in higher starting velocity at a given pressure. This is not necessarily desirable.

The cover 3 is then removed and a gentle radial flow of a suitable flush fluid is started in the direction of arrows 8 and 10 rotating valve 2 in position III, as shown. This effects the partial removal or dilution of the external ink (or ink cap- fluid mixture).

The ink stream has to be started within less than one second after the initiation of the flushing process, if mixing of flush fluid with ink inside the nozzle should not occur.

After starting the ink stream, the flushing process has to be continued for at least two more seconds. During this time the ink stream pumps some of the flush fluid off the surface, creating a radial flow and pulling particles along. Excess flush fluid flows off from the surface. If too much flush fluid is available, the stream is caught and floods the nozzle. This depends to some degree on the material and shape of the nozzle head. On polished metal surfaces of proper shape, the excess fluid flows...