Donald J Palmer

US Patent:

46859683, Aug 11, 1987

Filed:

May 27, 1986

Appl. No.:

6/866894

Inventors:

Donald J. Palmer - San Diego CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

C09D 1100

US Classification:

106 23

Abstract:

A process for preparing an aqueous-based ink composition for use in ink-jet printers in disclosed. The process comprises (a) forming a solution of a dye having at least one negatively charged functional group per molecule; (b) acidifying the solution; (c) cycling the solution through a reverse osmosis membrane to form a concentrate and a permeate, the concentrate including a cation of the compound associated with at least one functional group on the dye and the permeate including a cation formerly associated with at least one functional group; (d) adding water as necessary (e) concentrating the dye by reverse osmosis; and (f) admixing the concentrated dye with at least one glycol ether. The pH of the ink composition is maintained below about 7.

US Patent:

49438131, Jul 24, 1990

Filed:

Sep 25, 1989

Appl. No.:

7/412581

Inventors:

Donald J. Palmer - San Diego CA
Peter C. Morris - El Cajon CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

B41J 201

US Classification:

346 11

Abstract:

Printing of overhead transparencies, comprising non-absorbent, hydrophobic media such as polyester, is accomplished by an ink-jet printer by providing a time delay between printing of dots (10) at the same location or by printing adjacent dots. In one embodiment, a line is printed with dots at selected locations and the line is then reprinted with dots at the same locations, using the same color or a different color, as desired. An area-fill pattern (20), produced in accordance with the invention, is substantially homogeneous, lacking the drip lines and non-homogeneity (18) resulting from coalescence of prior art approaches.

US Patent:

48102920, Mar 7, 1989

Filed:

Dec 17, 1987

Appl. No.:

7/134648

Inventors:

Donald J. Palmer - San Diego CA
Adrienne R. Meuter - Encinitas CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

C09D 1100

US Classification:

106 23

Abstract:

An aqueous-based ink composition for use in ink-jet printers in disclosed. The composition comprises (a) a vehicle of about 5 to 95% water and the balance at least one glycol ether, such as diethylene glycol; (b) a dye, such as Food Black 2, having at least one negatively charged functional group per molecule, present in an amount up to about 10% of the vehicle composition; and (c) a cationic compound selected from the group consisting of alkanol ammonium compounds and cationic amide compounds, present in an amount such that there is at least one molecule of cationic compound for at least one of the negatively charged functional groups on the dye, the pH of the ink composition being maintained in the acidic region below about 7. The ink composition of the invention evidences minimal crusting and reduced evaporation loss of water. The solubility of anionic dyes is increased in the acidic medium over that otherwise obtainable, due to the presence of the alkanol ammonium compound of amide.