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Method for Producing Uniform Spot Size in a Color Ink Jet Printer

IP.com Disclosure Number: IPCOM000039285D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Mills, RN: AUTHOR [+2]

Abstract

This article describes a method for combining color ink droplets to produce mixed color without increasing the spot size relative to single ink droplet colors. Color ink jet printers typically offer a pallet of seven basic colors which are generated from four inks in a subtractive manner. The single ink primary colors (cyan, magenta, yellow, and black) are produced by a single ink drop from a nozzle containing the desired ink color. The two-ink secondary colors (red = magenta yellow, green = cyan + yellow, and blue = magenta + cyan) require a drop from two different inks which are superimposed to produce the desired color. The resultant spot size on paper, therefore, is different for colors produced from a single drop of ink as compared to those produced from two drops.

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Method for Producing Uniform Spot Size in a Color Ink Jet Printer

This article describes a method for combining color ink droplets to produce mixed color without increasing the spot size relative to single ink droplet colors. Color ink jet printers typically offer a pallet of seven basic colors which are generated from four inks in a subtractive manner. The single ink primary colors (cyan, magenta, yellow, and black) are produced by a single ink drop from a nozzle containing the desired ink color. The two-ink secondary colors (red = magenta yellow, green = cyan + yellow, and blue = magenta + cyan) require a drop from two different inks which are superimposed to produce the desired color. The resultant spot size on paper, therefore, is different for colors produced from a single drop of ink as compared to those produced from two drops. In general, this difference can be as great as 40% in diameter or 100% in area for a typical document. For three ink systems in which black is produced from a drop of cyan, magenta and yellow, the differential spot size problem is even more severe. The spot size difference can be compensated for in two ways. A first way is to produce a drop size that results in solid-area fill for single ink colors. While this option produces good text and image quality for the single ink colors, print quality for two ink colors is not optimal because of a reduction in effective resolution in color graphics and a stroke width too heavy for quality color text output. In a four-ink system using black as a single ink color, this approach is preferred for quality black text and graphics. A second way is to tailor the drop size for solid-area fill with the two ink colors. This approach produces inadequate fill with the single ink colors, and quality text or graphics require multiple passes of th...