Browse Prior Art Database

Ink Jet Head

IP.com Disclosure Number: IPCOM000085196D
Original Publication Date: 1976-Mar-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Pelkie, RE: AUTHOR [+3]

Abstract

A stream at the nozzle orifice of an ink jet head can be initiated and terminated without dribble and most clogs removed by having the capability of applying subatmospheric pressure at the supply side of the orifice. The occurrence of clogging is also reduced by insuring that the supply cavity in the head is continually scrubbed by ink flow during normal operation.

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Ink Jet Head

A stream at the nozzle orifice of an ink jet head can be initiated and terminated without dribble and most clogs removed by having the capability of applying subatmospheric pressure at the supply side of the orifice. The occurrence of clogging is also reduced by insuring that the supply cavity in the head is continually scrubbed by ink flow during normal operation.

An ink jet head having this capability is shown in the figure. The head comprises a pair of concentric tubes 1 and 2, with tube 1 forming a supply chamber about drain tube 2. Pressurized ink is supplied through a control valve 3 to an inlet elbow 4, in which tube 1 is mounted, to communicate with duct 5 of the elbow. At the opposite end of tube 1, an orifice plate 6 provides the nozzle. Tube 2 extends through elbow 4 to within a short distance of orifice plate 6 as at end 7. A vibrational transducer 8 is concentrically mounted on tube 1 to produce varicosities in the issuing ink stream. Tube 2 is connected at its left end through a control valve 9 to a vacuum sump.

During start-up, valve 3 is open while valve 9 is also open allowing pressurized ink to flow up to nozzle plate 6. However, the hydrodynamic resistance to flow is less in evacuated tube 1 so that no ink flows from the orifice at plate 6. Thereafter, valve 9 is closed, producing a water hammer effect on the ink, and causes an instantaneous ink jet to be formed at the orifice. At shutdown, valve 3 is closed and valve 9 is opened a...