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US 4,164,745 AGranted
Printing by modulation of ink viscosity
AssigneeNorthern Telecom Limited
InventorsPaolo Cielo, William D. Westwood
Life of this patent
Estimating the term…
Abstract
In a liquid ink printing system, ink is supplied to a reservoir at a constant pressure, and viscosity of ink in orifices in the reservoir wall is decreased by electrically heating the ink in the orifices. By this means the amount of ink deposited on a paper sheet moving past the orifices can be varied.
Claims8
Apparatus for printing by modulation of the viscosity of liquid ink, comprising:
- a reservoir for holding a supply of liquid ink of a predetermined viscosity, said reservoir including a wall and at least one orifice of a predetermined size in said wall;
- means for supplying ink to said reservoir at a predetermined pressure;
- electrical heating means associated with said orifice, said electrical heating means being controllably variable;
- and
- a bye-pass passage intercepting said orifice and connected to said reservoir;
- whereby when no heating is applied said ink flows through said bye-pass, application of heat reducing the viscosity of the ink and increasing the ink flow above the capacity of said bye-pass and ink issuing from said orifice.
3 more elements
A method of printing by undulating the viscosity of a liquid ink, comprising:
- feeding liquid ink having a predetermined viscosity to a reservoir at a predetermined pressure, said reservoir having at least one orifice in a wall thereof, said ink flowing to said orifice at a predetermined rate;
- electrically heating said ink at a controllably variable rate to vary the viscosity of the ink to thereby increase the flow of ink through said orifice;
- bye-passing ink from said orifice, all of the flow through said orifice bye-passed at one heating level, increased heating of said ink causing ink to flow from said orifice;
- feeding a paper sheet over said orifice for deposition of ink thereon.
1 more element
Dependencies are inferred from the claim text.