Hewlett-packard Company

Kenneth A Norton

Norman E Pawlowski

Loren E Johnson

Margaret L Wooding

Bruce Cowger

James G Bearss

David E Hackleman

Mary B Heffernan

If a small amount of alcohol (about 0.05 to 6 wt %) is added to water-based inks for thermal ink-jet printing, the resultant print has a rapid dry time and improved smear resistance. In addition, a high quality print is obtained, even on plain paper.

Ink composition having rapid dry time and high print quality for plain

A dye used in ink compositions for ink-jet printing comprises an aromatic dye molecule having attached to the aromatic nucleus thereof from 2 to 10 alkylamino groups having the formula selected from the group consisting of:

Dyes containing alkylamino groups for ink-jet printing inks

The cleanliness in foams used as ink reservoirs and ink delivery systems in ink-jet printing is determined by at least one of two methods. In the first method, the amount of non-volatile residues is measured. An amount of NVRs of less than about 0.2 wt/wt % is sufficient to provide adequate ink fluid properties. In the second method, the surface tension is measured for ink vehicle prior to and following exposure to the foam. For inks formulated for specially-coated paper printing, so long as the surface tension following exposure to the foam is at least about 40 dyne/cm, then adequate ink fluid properties are assured. For inks formulated for plain paper printing, so long as the drop in surface tension is less than about 7 dyne/cm as compared to ink vehicle not so exposed, then adequate ink fluid properties are assured.

Determination of cleanliness level of foam reservoir

An ink composition for printing on plain paper and other media using a thermal ink-jet printer is provided. The ink composition comprises at least one member selected from the group consisting of ethylene glycol and diethylene glycol, present in an amount ranging from about 5 to 10 wt %; dye, ranging from about 1 to 4 wt %; and the balance water. A biocide ranging from about 0.01 to 0.3 wt % and/or a buffering agent ranging in concentration from about 0.05 to 0.5 wt % may also be included. The ink compositions of the invention permit printing on a large variety of plain papers, including bonds, photocopy paper and laser jet paper. These compositions are an improvement over other ink compositions and permit both high quality and letter quality printing to be achieved.

Low glycol inks for plain paper printing

An ink composition is provided for an ink-jet printer, preferably a thermal ink-jet printer. The composition comprises about 5 to 40 wt % glycol, about 60 to 90 wt % water, about 0.001 to 10 wt % polymer blend and about 1 to 7 wt % dye. The polymer blend includes both uncharged and charged monomeric units.

Ink-jet ink for plain paper printing

A process for increasing the solubility of carbon black in desired solvents is provided. The process comprises (a) forming a suspension of the carbon black in a non-reactive medium, such as an aromatic hydrocarbon, (b) adding a silylating agent, such as an organosilane, (c) removing the reaction product of the silating agent and the carbon black, and (d) forming a dispersion of the reaction product in a solvent for use as an ink-jet printing fluid. The increased dispersibility of the carbon black of the invention results in a more non-settling suspension of the carbon black 'molecules' than otherwise obtained.

Growing community of inventors

Houston, TX, United States of America

Kenneth A Norton