Hewlett-packard Company

Hewlett-packard Development Company, L.p.

John M Skene

Suraj L Hindagolla

Charles L Thierheimer, Jr

Matthew Allen Shepherd

Garrard Hume

Norman E Pawlowski

James P Shields

Hiang P Lauw

Loren E Johnson

Majid Azmoon

Donald G Harris

Nicholas Nicoloff, Jr

Joseph H Bauman

Karsten N Wilson

Nancy Leigh Herald

A method and apparatus for calibrating color in an inkjet printing system initiates a calibration procedure by instructing an inkjet printer to print a color calibration sample. From the color calibration sample, an analysis is performed to select a color calibration based on the sample. Based on the characteristics of the selected color calibration, the color of the inkjet printer is calibrated.

Color calibration in an inkjet printer

A replaceable printer component having an integral memory for use in a printing system includes a semiconductor die and a plurality of circuits formed on the semiconductor die. Each circuit is associated with and indicates the state of a bit in the memory. The memory stores a plurality of functional bits that must match values expected by the printing system for proper operation of the printing system. The memory stores a plurality of informational bits that are not critical to proper operation of the printing system. A large percentage of the circuits associated with the functional bits are positioned substantially near a center of the semiconductor die.

Robust bit scheme for a memory of a replaceable printer component

A system and method for detecting an error in data received from a memory of a replaceable printer component includes providing a first parity bit associated with a first data item. The first data item and the first parity bit are stored in the memory. The printer includes a plurality of electrically conductive lines. The memory includes a plurality of bits. At least one of the electrically conductive lines is associated with each bit. The first data item and the first parity bit are read from the memory. An electrical test of at least one of the electrically conductive lines is performed. An error in the first data item is identified based on the first parity bit read from the memory and the electrical test.

At least two different pixel densities are used for different printing devices--such as inkjet pens--that operate concurrently, or different printing steps that proceed concurrently, to produce respective image swaths in a single, pixel-based printing machine. The different print devices or steps produce image swaths of respective different swath heights. In one form of the invention, the taller-swath-height printing device operates at lower pixel density, spreading its colorant over a greater area while printing-medium advance keeps pace with operation of the shallower-swath-height printing device. This procedure allows more drying and penetrating time for the colorant applied by the taller-swath device, thereby improving print attributes such as bleed, offset, cockle, curl, overall drying time and throughput. In another form of the invention the taller-swath device operates at higher pixel density, providing physical and temporal separation of colorant application from the two printing devices--to avoid adverse interfering effects between reactive inks.

Mixed-density print masking in a mixed-swath-height printer

A set of thermal ink-jet inks and method for formulating the same are provided in which the cyan, magenta, and yellow inks contain a combination of surfactants and inorganic salts designed to reduce both color to color bleed as well as black to color bleed. In general, the present cyan, magenta, and yellow inks each comprise about 0.1 to 4 wt. % of at least one dye; about 3 to 20 wt. % of at least one diol; 0 to about 5 wt. % of at least one glycol ether; about 3 to 9 wt. % of 2-pyrrolidone; up to about 4 wt. % of at least one component selected from the group consisting of biocides and buffers; and water. To achieve a reduction in color to color and black to color bleed, the cyan, magenta, and yellow inks are formulated to further comprise the following combination of surfactants and inorganic salts: (a) a surfactant component comprising about 1 to 4 wt. % of a first surfactant consisting essentially of at least one secondary alcohol ethoxylate surfactant predominantly having 4 to 8 ethoxylated units and an aliphatic chain having about 12 to 18 carbon atoms; and (b) about 3 to 6 wt. % of at least one inorganic salt component.

Thermal ink-jet inks having reduced black to color and color to color

Inks for ink-jet printing have improved water resistance and smear resistance when they contain from about 2.5 to 25%, preferably from about 7.5% to about 12.5%, by weight, 2-pyrrolidone, N-(2-hydroxyethyl)-2-pyrrolidone, or mixtures thereof.

Smear resistant inks for ink-jet printers

Inks for ink-jet printing containing Direct Black 168 dye have improved water resistance when the sodium cations on the dye are replaced with cations selected from the group consisting of ammonium, polyfunctional, and volatile amine cations.

Waterfastness of DB-168 ink by cation substitution

Inks for ink-jet printing have improved smear resistance when they contain from about 15 to 50%, preferably from about 20% to about 30%, formamide.

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Lake Oswego, OR, United States of America

John M Skene