Patent Application
20080030561
Composite colors were printed on plain paper using magenta and yellow colored inks. The colored inks were prepared with magenta or yellow pigment particles and polymeric dispersant/stabilizing groups. A yellow colored ink having anionic stabilizing groups (“anionic yellow 1”), a yellow colored ink having cationic stabilizing groups (“cationic yellow 1”), a magenta colored ink having anionic stabilizing groups (“anionic magenta 1”), and a magenta colored ink having cationic stabilizing groups (“cationic magenta 1”) were prepared. Each of the colored inks was formulated with the ink vehicle shown in Table 1.
The inks were used to fill thermal inkjet pens and were printed on plain paper using a Hewlett Packard Deskjet 6540 printer. The printed samples were allowed to dry at an ambient temperature. As previously stated, “Lightness,” as the term is used herein, refers to the L* value measured in CIELAB color space. For example, in the CIELAB color space (which allows the specification of color perceptions in terms of a three-dimensional space), the lightness, expressed as L*, extends from zero (black) to 100 (white). It is to be understood that the attributes described herein may be described using other measurement systems (e.g., Munsell) that depict the color stimuli and performance characteristics discussed herein. 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). Alternative terms such as h* (hue angle) and C* (chroma) may also be used to describe a given color. Lightness (L*), (a*), and (b*) were measured, and color richness or saturation was calculated as C*/L*.
Tables 2-5 show the color richness of composite red colors formed using anionic yellow 1 ink with cationic magenta 1 ink (Tables 2 and 3), anionic yellow 1 ink with anionic magenta 1 ink (Table 4, comparative example 1), and cationic yellow 1 ink with cationic magenta 1 ink (Table 5, comparative example 2).
The above results show that a composite red color obtained with oppositely charged magenta and yellow inks printed on plain paper exhibits increased color richness when compared with composite red colors obtained with magenta and yellow inks having the same charge printed on plain paper.
Composite red colors were printed on different papers using magenta and yellow colored inks. Composite blue colors were printed on different papers using magenta and cyan colored inks. The colored inks were respectively prepared with pigment loads of about 5% magenta, 5% yellow, or 4% cyan, and polymeric dispersant/stabilizing groups.
A magenta colored ink having anionic stabilizing groups (“anionic magenta 2”), a magenta colored ink having cationic stabilizing groups (“cationic magenta 2”), a cyan colored ink having anionic stabilizing groups (“anionic cyan”), a cyan colored ink having cationic stabilizing groups (“cationic cyan”), a yellow colored ink having anionic stabilizing groups (“anionic yellow 2”), and a yellow colored ink having cationic stabilizing groups (“cationic yellow 2”) were prepared. Each of the colored inks was formulated with an ink vehicle similar to that shown in Table 1 of Example 1, with the exception of the higher pigment loads (5% magenta, 5% yellow, or 4% cyan).
The inks were used to fill thermal inkjet pens and were printed on Hewlett Packard printing paper and on nine other types of paper. Table 6 shows the saturation of composite red colors formed using anionic yellow 2 ink with anionic magenta 2 ink (comparative example 3), anionic magenta 2 ink with cationic yellow 2 ink, and cationic magenta 2 ink with anionic yellow 2 ink. Table 7 shows the saturation of composite blue colors formed using anionic magenta 2 ink with anionic cyan ink (comparative example 4), anionic magenta 2 ink with cationic cyan ink, and cationic magenta 2 ink and anionic cyan ink. The saturation results of the composite colors on the HP printing paper, and the average of the saturation results for the nine other papers are shown.
The above results show that a composite red color and a composite blue color obtained with oppositely charged inks exhibit increased saturation, and thus enhanced color richness, when compared with composite red and blue colors obtained with inks having the same charge.
Embodiment(s) of the color composites disclosed herein advantageously have increased color richness when printed on a variety of media. Furthermore, the composite colors may be achieved without additional fixer fluids and pen chambers.
While several embodiments have been described in detail, it will be apparent to those skilled in the art that the disclosed embodiments may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
