Ink supply system for ink jet printing apparatus

Abstract

Abstract A recoverable ink supply system, comprising both method and apparatus, includes a primary reservoir which is connected by suitable fluid conduit to a prime, or primary, pump. The prime pump transfers the liquid ink from the primary reservoir to an intermediate reservoir at an increased pressure causing a lower pressure condition in the sealed primary reservoir and a higher pressure condition in the sealed intermediate reservoir. Secondary, or metering pumps, receive pressurized ink from the intermediate reservoir after it is filtered at the reservoir outlet, and supply metered, higher pressure ink through combined filter/pressure fluctuation dampers to associated on/off control valves. The control valves permit the flow of the pressurized ink into the print heads wherefrom the ink is discharged at a controlled uniform velocity. According to known print head technology, a uniform series of ink drops is discharged from the print heads which are either deflected to a recording medium to produce characters or collected by a catcher for recycling to the primary reservoir. Ink recycled to the primary reservoir contains entrapped air, or gas, and the major portion of the entrapped gas is drawn out of the ink in the low pressure reservoir. The remaining gas, both dissolved and undissolved, is carried to the intermediate reservoir wherein the remaining undissolved gases are absorbed in the ink solution due to the high pressure therein. This absorption phenomenon stabilizes the ink and, this stabilized ink is then supplied to the metering pumps before delivery to the print heads.

Inventors

• 👤 Richard A. Hein

Bibliographic Details