Hewlett-Packard Company

Roger F Evans

Norman E Pawlowski

Kenneth J Courian

Charles L Thierheimer, Jr

A method is provided for enhancing and accelerating wetting of hydrophobic foams for use as ink reservoirs in ink-jet printer pens. First, the foam is placed in a prewet bath, having already been compressed to expel air. The prewet bath contains an aqueous solution with a low molecular weight alcohol additive, such as n-propanol, ranging in concentration from about 3 to 10 wt. %. Second, the foam is repeatedly compressed and allowed to expand while in the prewet bath, thereby promoting the foam's absorbance of prewetting solution and further improving foam wettability. Finally, the foam is removed from the prewet bath and is compressed to expel excess prewetting solution. The foam retains residual alcohol from the prewet bath that subsequently becomes a constituent of the ink stored in the foam. In addition to improving the wetting process for hydrophobic foam, the alcohol additive prevents orifice plugging within ink-jet pens by becoming a residual constituent of the ink and wetting pen parts through ink usage.

Addition of alcohol to prewet solutions to enhance and accelerate

Multi-color ink-jet pens having an orifice set associated with each color are primed by an apparatus that avoids mixing of two colors during priming. A resilient seal forms a chamber that encloses the orifice sets. The chamber is connected to a vacuum source to reduce the pressure in the chamber for drawing ink out of the orifices. A set of suction tubes connects to the vacuum source, with each tube terminating within the chamber in closely spaced relation with a corresponding orifice set for drawing excess ink away from the orifice set, thereby preventing the various colors of primed ink from mixing.

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Corvallis, OR, United States of America

Roger F Evans