Browse Prior Art Database

Ink Dump for Ink Jet Printers

IP.com Disclosure Number: IPCOM000052000D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Uhen, D: AUTHOR

Abstract

In the IBM 6640 ink jet system, the ink stream supplied to the head is turned on and off with a two-way valve. In the first position with the ink stream on, the inlet port of the valve is connected directly to the head; in the second position when the valve is off, the inlet is stopped up and a port is opened from the head to the vent line which allows the pressure to drop very quickly to atmospheric pressure in the head, preventing contamination of the nozzle face. Any excess ink which is vented is pushed through a dump line to the siphon break which is connected to a surge tank. The dump tank described hereinafter inhibits excessive air flow through the nozzle orifice, which results in evaporation and ultimate clogging of the valve's internal passageway (and nozzle).

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Ink Dump for Ink Jet Printers

In the IBM 6640 ink jet system, the ink stream supplied to the head is turned on and off with a two-way valve. In the first position with the ink stream on, the inlet port of the valve is connected directly to the head; in the second position when the valve is off, the inlet is stopped up and a port is opened from the head to the vent line which allows the pressure to drop very quickly to atmospheric pressure in the head, preventing contamination of the nozzle face. Any excess ink which is vented is pushed through a dump line to the siphon break which is connected to a surge tank. The dump tank described hereinafter inhibits excessive air flow through the nozzle orifice, which results in evaporation and ultimate clogging of the valve's internal passageway (and nozzle).

When the ink in the conventional two-way valve is vented, the inertia of the fluid in the dump line may pull a vacuum on the head when the ink decelerates. The negative pressure pulse may pull air in through the nozzle orifice, all of which can be alleviated to some extent by shortening the dump line, but this increases problems in evaporation rates. When the printer sits for an extended period of time, the fluid left in the dump line slowly evaporates. With a short dump line, evaporation may drain the line and prematurely dry up the fluid in the valve, which results in the clogging of the valve's internal passageways and a breakdown in performance.

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