Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2002-03-11
2004-01-06
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031520, C534S709000, C534S716000
Reexamination Certificate
active
06673140
ABSTRACT:
FIELD OF THE INVENTION
The present invention is drawn to the area of ink-jet imaging. More specifically, the present invention is drawn to ink-jet inks that can be used in conjunction with cyan, magenta, and yellow ink set systems for improved gamut and lightfastness while maintaining good chroma in the case of color ink and lightness in the case of black ink.
BACKGROUND OF THE INVENTION
In recent years, computer printer technology has evolved to a point where very high resolution images can be transferred to various types of media, including paper. One particular type of printing involves the placement of small drops of a fluid ink onto a media surface in response to a digital signal. Typically, the fluid ink is placed or jetted onto the surface without physical contact between the printing device and the surface. Within this general technique, the specific method that the ink-jet ink is deposited onto the printing surface varies from system to system, and can include continuous ink deposit and drop-on-demand ink deposit.
With regard to continuous printing systems, inks used are typically based on solvents such as methyl ethyl ketone and ethanol. Essentially, continuous printing systems function as a stream of ink droplets are ejected and directed by a printer nozzle. The ink droplets are directed additionally with the assistance of an electrostatic charging device in close proximity to the nozzle. If the ink is not used on the desired printing surface, the ink is recycled for later use. With regard to drop-on-demand printing systems, the ink-jet inks are typically based upon water and solvents such as glycols. Essentially, with these systems, ink droplets are propelled from a nozzle by heat or by a pressure wave such that all of the ink droplets ejected are used to form the printed image.
There are several reasons that ink-jet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of these reasons include low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. However, though there has been great improvement in ink-jet printing, accompanying this improvement are increased demands by consumers in this area, e.g., higher speeds, higher resolution, full color image formation, increased stability, etc. As new ink-jet inks are developed, there have been several traditional characteristics to consider when evaluating the ink in conjunction with a printing surface or substrate. Such characteristics include edge acuity and optical density of the image on the surface, dry time of the ink on the substrate, adhesion to the substrate, lack of deviation in ink droplet placement, presence of all dots, resistance of the ink after drying to water and other solvents, long term storage stability, and long term reliability without corrosion or nozzle clogging. Though the above list of characteristics provides a worthy goal to achieve, there are difficulties associated with satisfying all of the above characteristics. Often, the inclusion of an ink component meant to satisfy one of the above characteristics can prevent another characteristic from being met. Thus, most commercial inks for use in ink-jet printers represent a compromise in an attempt to achieve at least an adequate response in meeting all of the above listed requirements.
In general, ink-jet inks are either dye- or pigment-based inks. Both are typically prepared in an ink vehicle that contains the dye and/or the pigment. Dye-based ink-jet inks generally use a liquid colorant that is usually water-based to turn the media a specific color. Conversely, pigmented inks typically use a solid or dispersed colorant to achieve color.
Color characteristics of dye-containing inks play an important role in the quality of the printed ink-jet image. Perceived color quality can be characterized using any one of several color space systems, such as CIELAB or Munsell, as is well known in the art. With respect to Munsell color space, a given color is defined using three terms, namely Hue, Value, and Chroma. With respect to CIELAB color space, a color is defined using three terms L*, a*, and b*. With this system, L* defines the lightness of a color, and it ranges from 0 (black) to 100 (white). Additionally, the terms a* and b*, together, define the hue, where a* ranges from a negative number (green) to a positive number (red), and b* ranges from a negative number (blue) to a positive number (yellow). Additional terms such as h° (hue angle) and C* (chroma) are used to further describe a given color, as is known to those skilled in the art.
Inks are known which possess one or more of the above described properties. However, few inks are known that possess all of these properties, since an improvement in one property often results in the degradation in another property. Accordingly, investigations continue into developing ink formulations that have improved properties and that do not improve one property at the expense of the others. However, many challenges still remain to further improve the image quality and lightfastness of ink-jet prints without sacrificing pen performance and reliability.
SUMMARY OF THE INVENTION
It has been recognized that the use of certain ink-jet inks having certain dyes can be used in conjunction with cyan, magenta, and yellow ink set systems for improved image quality. Specifically, a magenta ink for ink-jet printing can comprise an effective amount of an ink vehicle; and an effective amount of a magenta dye having the following chemical structure:
wherein M is H or a monovalent ion, such as Na
+
, Li
+
, K
+
, NH
4
+
, and combinations thereof.
In another embodiment, a black inkjet ink for use with a color ink set can comprise an effective amount of an ink vehicle; and an effective amount of a black dye having the following chemical structure:
wherein M is H or a monovalent ion, such as Na
+
, Li
+
, K
+
, NH
4
+
, and combinations thereof.
The ink-jet inks described above can be used as part of an ink set for ink-jet printing. Such an ink set can comprise a three-ink ink set of cyan ink, magenta ink, and yellow ink; and a second magenta ink having a magenta dye load from 0.1% to 7.0% by weight, wherein the magenta dye has the structure of Formula 1. An alternative ink set for ink-jet printing can comprise a three-ink ink set of cyan ink, magenta ink, and yellow ink; and a black ink having a black dye load from 0.1% to 10.0% by weight, wherein the black dye has the structure of Formula 2.
In a more detailed aspect of the present invention, a six-ink ink set for ink-jet printing can comprise 1) a magenta ink-jet ink having a dye load from 2.0% to 7.0% by weight; 2) a second magenta ink-jet ink having a dye load from 0.1% to 2.0% by weight and having the structure set forth in Formula 1, with the proviso that the magenta ink-jet ink and the second magenta ink-jet ink are not the same composition; 3) a black ink-jet ink having a dye load from 0.1% to 10.0% by weight; 4) a cyan ink-jet ink having a dye load from 2.0% to 7.0% by weight; 5) a second cyan ink-jet ink having a dye load from 0.1% to 2.0% by weight, with the proviso that the cyan ink-jet ink and the second cyan ink-jet ink are not the same composition; and 6) a yellow ink-jet ink having a dye load from 2.0% to 10.0% by weight.
In an alternative more detailed embodiment of the present invention, a six-ink ink set for ink-jet printing can comprise 1) a magenta ink-jet ink having a dye load from 2.0% to 7.0% by weight; 2) a second magenta ink-jet ink having a dye load from 0.1% to 2.0% by weight, with the proviso that the magenta ink-jet ink and the second magenta ink-jet ink are not the same composition; 3) a black inkjet ink having a dye load from 0.1% to 10.0% by weight and having the structure set forth in Formula 2; 4) a cyan ink-jet ink having a dye load from 2.0% to 7.0% by weight; 5) a second cyan ink-jet ink having a dye load from 0.1% to 2.0% by weight, wi
Dupuy Charles G.
Tyrell Paul
Wang Patricia A
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