Organic compounds -- part of the class 532-570 series – Organic compounds – Polycyclo ring system containing anthracene configured ring...
Reexamination Certificate
2001-08-24
2002-08-20
Pryor, Alton (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Polycyclo ring system containing anthracene configured ring...
Reexamination Certificate
active
06437155
ABSTRACT:
BACKGROUND OF THE INVENTION
1 Field of Invention
The present invention relates to selected anthraquinone colorants and their use in printing inks and toners, particularly phase change inks.
2. Description of Related Art
Many inks and toners have been developed in recent years for use in printing and xerographic processes, and are herein referred to as printing inks and toners. More recently, there has been a strong focus on colored printing inks and toners for creation and/or reproduction of colored images. Such printing inks and toners have specific requirements in terms of both colors and compatibility with the apparatus, substrates and conditions with which they are used. Likewise, the individual components of such printing inks and toners have specific requirements in terms of the same above variables plus compatibility with one another.
Phase change inks in digital printing applications (also sometimes called solid inks or hot melt inks) have in the past decade gained significant consumer acceptance as an alternative to more traditional printing systems such as offset printing, flexography printing, gravure printing, letterpress printing and the like. Phase change inks are especially desirable for the peripheral printing devices associated with computer technology, as well as being suitable for use in other printing technologies such as gravure printing applications as referenced in U.S. Pat. No. 5,496,879 and German Patent Publications DE 4205636AL and DE4205713AL assigned to Siegwerk Farlenfabrik Keller, Dr. Rung & Co.
In general, phase change inks are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the printing media, they quickly solidify to form a predetermined pattern of solidified ink drops.
They are easy to use and safe. They can be easily loaded into the printer by the user, generally in the form of solid sticks of yellow, magenta, cyan and black ink having a solid consistency similar to children's crayons. Inside the printer, these inks are melted at an elevated temperature in a print head having a number of orifices, through which the melted ink will be ejected onto the desired substrate such as media like paper or an overhead transparency film. Alternatively, the melted ink may be transferred to a rotating drum or the like and then transferred to the substrate. As the ink cools on the substrate, it re-solidifies into the desired image. This resolidification process, or phase change, is substantially instantaneous and a printed, dry image is thus available as the substrate leaves the printer, and is available immediately to the user.
Phase change inks need not contain solvents or diluents that can lead to undesired emissions. In all, the use and specific design of phase change inks address many of the limitations of more traditional ink and printing processes.
Furthermore, because the ink is in a cool, solid form at any time when the user can actually come in contact with the ink, and the ink is in a molten state only inside the printer (inaccessible to the user), it is generally safe to use. These inks also have long-term stability for shipping and long storage times.
Phase change inks generally comprise a phase change ink carrier composition, which is combined with at least one compatible phase change ink colorant. The carrier composition has been generally composed of resins, fatty acid amides and resin derived materials. Also, plasticizers, waxes, antioxidants and the like have been added to carrier compositions. Generally the resins used are water-insoluble and the carrier composition preferably contains no ingredients that are volatile at the jetting temperatures employed. Also, these carrier ingredients are preferably chemically stable so as not to lose their chemical identity over time and/or under elevated temperature conditions.
Preferably, a colored phase change ink will be formed by combining an ink carrier composition with compatible colorant material, preferably subtractive primary colorants. The subtractive primary colored phase change inks comprise four component dyes, namely, cyan, magenta, yellow and black. U.S. Pat. Nos. 4,889,560 and 5,372,852 teach preferred subtractive primary colorants employed. Typically these may comprise dyes from the classes of Color Index (C.I.) Solvent Dyes, C.I. Disperse Dyes, modified C.I. Acid and Direct Dyes, as well as a limited number of C.I. Basic Dyes. Suitable colorants also include appropriate polymeric dyes, such as those described in U.S. Pat. No. 5,621,022 and available from Milliken & Company as Milliken Ink Yellow 869, Milliken Ink Blue 92, Milliken Ink Red 357, Milliken Ink Yellow 1800, Milliken Ink Black 8915-67, uncut Reactant Orange X-38, uncut Reactant Blue X-17, and uncut Reactant Violet X-80, and those described in U.S. Pat. No. 5,231,135.
Colored resin reaction products such as those described in U.S. Pat. No. 5,780,528 issued Jul. 14, 1998, and assigned to the assignee of the present invention, are also suitable colorants.
Polymeric colorants have also been utilized in preparing commercial phase change ink jet inks, as well as potentially for use in other applications, such as gravure printing, and other types of inks and coating applications where coloration is desired. For example, the specific class of polymeric dyes characterized by: (1) an organic chromophore having (2) a polyoxyalkylene substituent and optionally (3) a carboxylic acid or non-reactive derivative thereof covalently bonded to the polyoxyalkylene substituent, have been described in U.S. Pat. No. 5,621,022 (Jaeger et al.).
Anthraquinone dyes and pigments have been employed as chromogens for many applications where colorants are required. Furthermore, it is known to make many derivatives of anthraquinones for specific colorant applications. Yet, anthraquinones and their derivatives have some shortcomings when used in phase change inks. For example, solubility and blooming problems often arise when known anthraquinone dyes are used in phase change inks. They are believed to be caused by the planar nature of the molecules of these colorants. Aggregation of dye moieties can take place more readily when the dye molecules are planar in nature. This aggregation leads to solubility problems at operating temperatures inside printers. Furthermore, unaggregated dye molecules may work their way to the surface of the hardened phase change ink stick, resulting in blooming problems. Furthermore, the manufacturing processes for making commercially available anthraquinone derivative dyes have several disadvantages (e.g., solvents are typically used in making such derivatives, thus requiring solvent recovery, and such processes also involve elaborate purification procedures).
SUMMARY OF THE INVENTION
The present invention retains known advantages of anthraquinone chromogens (e.g., wide variety of red to purple to cyan shades, outstanding lightfastness and thermal stability) while overcoming solubility and blooming problems of conventional anthraquinone colorants as well as eliminating manufacturing disadvantages of their preparation.
One aspect of the present invention is directed to solid ink and toner compositions that comprise a colorant that comprises a monofunctional amine-substituted-9,10-anthraquinone compound, optionally with at least one carrier component.
It is a feature of the present invention that this class of anthraquinone, dyes can be easily tailored by adjusting the degree of substitution by monofunctional amine substitutents to provide a desirable range of particular color shades.
It is another feature of the present invention that preferred dyes of this class of anthraquinones are liquid at the elevated temperatures at which phase change ink printers and toner fusing apparatus operate, yet are solid at room temperatures.
It is another feature of the present invention that these anthra
Banning Jeffery H.
Titterington Donald R.
Oliff & Berridg,e PLC
Pryor Alton
Xerox Corporation
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