Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-03-29
2003-09-02
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
Reexamination Certificate
active
06613134
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a jet printing ink composition which gives an image of high quality and which is stably jetted out.
BACKGROUND OF THE INVENTION
Ink-jet printers have been widely used in not only offices but also homes with the spread of personal computers. As image-receiving material for ink-jet printer, ordinary paper, film and cloth have been used as well as paper specialized in ink-jet printing. On the other hand, as ink for ink-jet printing, oleaginous ink, aqueous ink and solid ink have been proposed. Practically, aqueous ink is mainly used because it less smells and is easy and safe to produce and deal with.
An aqueous ink is generally prepared by dissolving water-soluble dye in water. The aqueous ink comprising aqueous dye solution is excellent in transparency and color density, but is poor in water resistance and light resistance. Further, when printed on ordinary paper, the aqueous ink is apt to bleed to impair printing quality.
An aqueous ink comprising dispersed pigment or dye in place of water-soluble dye has been proposed (for example, in Japanese Patent Provisional Publication Nos. 56(1981)-157468, 4(1992)-18468, 10(1998)-110126 and 10(1998)-195355). This ink is improved in water resistance in some degree, but that resistance is still insufficient. Further, the dispersed pigment or dye is generally inferior to water-soluble dye in coloration. Furthermore, since the dispersion is unstable, the pigment or dye often chokes a jet nozzle.
Japanese Patent Provisional Publication No. 58(1983)-45272 describes dye enclosed in particles of urethane polymer latex. However, if the dye is enclosed in the particles to such an extent that sufficient density can be obtained, troubles on dispersion stability of the colored particles are often observed.
Further, the ink comprising dispersed pigment or dye is hardly spread and fixed on porous glossy paper. Recent ink jet printers often print images of photographic quality on porous photographic glossy paper. Accordingly, if the ink is insufficiently spread and fixed on the paper, the image has poor wear resistance.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an aqueous ink which is excellent in coloration, which does not choke a jet nozzle, in which fine particles are stably dispersed, and particularly which is spread and fixed well on porous photographic glossy paper.
The present invention provides a jet printing ink composition containing a dye dissolved in an oil phase, which is emulsified in an aqueous medium, wherein the oil phase comprises an organic solvent having a boiling point of not lower than 150° C., said oil phase having a viscosity in the range of 20 to 8,000 mPa·s at 25° C., and wherein droplets of the emulsified oil phase have a volumetric average diameter of not larger than 100 nm.
The invention also provides a process for the preparation of a jet printing ink composition, which comprises the steps of: dissolving a dye in an organic solvent having a boiling point of not lower than 150° C. to form an oil phase having a viscosity in the range of 20 to 8,000 mPa·s at 25° C.; and then emulsifying the oil phase in an aqueous. medium to form droplets of the oil phase having a volumetric-average diameter of not larger than 100 nm.
The invention further provides an ink-jet recording method in which an image is recorded with ink drops on an image-receiving material, said image-receiving material comprising a support and an image-receiving layer containing white inorganic pigment particles, and said ink drops being jetted out according to recording signals, wherein the ink drops consist of a jet printing ink composition containing a dye dissolved in an oil phase, which is emulsified in an aqueous medium, and wherein the oil phase comprises an organic solvent having a boiling point of not lower than 150° C., said oil phase having a viscosity in the range of 20 to 8,000 mPa·s at 25° C., and wherein droplets of the emulsified oil phase have a volumetric average diameter of not larger than 100 nm.
DETAILED DESCRIPTION OF THE INVENTION
The jet printing ink composition of the invention is an emulsion in which droplets of an oil phase are emulsified in an aqueous medium.
The term “aqueous medium” means water or a mixture of water and an organic solvent, which is miscible with water. The aqueous medium can further contain additives such as a surfactant, a wetting agent, a stabilizing agent and an antiseptic.
The oil phase can be obtained by dissolving an oleaginous dye in a water-incompatible organic solvent having a high boiling point (which is not lower than 150° C.). The oil phase can contain, if needed, additives such as an ultraviolet absorbing agent, an oxidation inhibitor, a stabilizing agent and a viscosity adjusting agent.
The oil phase has a specific gravity preferably in the range of 0.90 to 1.15 at 25° C., more preferably in the range of 0.95 to 1.10 at 25° C., and most preferably in the range of 0.95 to 1.05 at 25° C.
The oil phase has a viscosity in the range of 20 to 8,000 mPa·s, preferably in the range of 100 to 4,000 mPa·s, and more preferably in the range of 200 to 3,000 mPa·s. If the viscosity is too high, the ink is hardly spread and fixed on porous photographic glossy paper, and accordingly the wear resistance of printed image is impaired.
The viscosity of the oil phase can be measured according to known methods (for example, described in “JIKKEN KAGAKU KOZA”, 4th edition, pp.113). It can be also measured by means of a commercially available viscometer (e.g., rotating-vibrating viscometer).
The viscosity of the oil phase can be controlled by the amount of the organic solvent dissolving the oleaginous dye and/or by selecting the solvent and the dye. The viscosity of the organic solvent directly affects that of the oil phase. Further, the oil phase having a low viscosity can be obtained by using an oleaginous dye having a molecular structure in which many ester linkages or ether linkages are contained and rotation between C—C or C-hetero atom is restricted in a small degree.
The oleaginous dye preferably has a water-solubility of not more than 1 wt.%.
Examples of yellow dye include aryl azo dyes, hetero aryl azo dyes, azomethine dyes, methine dyes and quinone dyes. The aryl azo dyes and the hetero aryl azo dyes can have, as a coupling component, phenols, naphthols, anilines, pyrazolones, pyridones or open-chained active methylene compounds. The azomethine dyes can have open-chained active methylene compounds as a coupling component. The methine dyes include benzylidene dyes and monomethine oxonol dyes. The quinone dyes include naphthoquinone dyes and anthraquinone dyes.
Further, quinophthalone dyes, nitro dyes, nitroso dyes, acridine dyes and acridinone dyes can be also used as yellow dye. A dye whose chromophore partially dissociates to give yellow color can be also used as yellow-dye. In that dye, a counter cation for dissociation may be either an inorganic cation (e.g., alkali metal ion, ammonium ion) or an organic cation (e.g., pyridinium ion, quaternary ammonium ion). Further, a polymer cation having a partial structure of cation can be used as a counter cation.
Examples of magenta dye include aryl azo dyes, hetero aryl azo dyes, azomethine dyes, methine dyes, carbonium dyes, quinone dyes and condensed pqlycyclic dyes. The aryl azo dyes and the hetero aryl azo dyes can have phenols, naphthols and anilines as a coupling component. The azomethine dyes can have, as a coupling component, pyrazolones and pyrazolotriazole open-chained active methylene compounds. The methine dyes include arylidene dyes, styryl dyes, merocyanine dyes and oxonol dyes. The carbonium dyes include diphenylmethane dyes, triphenylmethane dyes and xanthene dyes. The quinone dyes include anthraquinone dyes and anthrapyridone dyes. The condensed polycyclic dyes include dioxadine dyes.
A dye whose chromophore partially dissociates to give magenta color can be also used as magenta dye. In that dye, a counter cation for dissociation may be either an inorganic cation (e.g., a
Fuji Photo Film Co. , Ltd.
Klemanski Helene
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