Polymeric additives to improve print quality and permanence attributes in ink-jet inks

Abstract

One-part and two-part fixatives are provided in conjunction with underprinting or overcoating at least one ink printed on a print medium. The one-part fixative of the present invention comprises a polymer in a vehicle. The polymer is selected from the group consisting of vinyl-based polymers, condensation polymers, and copolymers thereof and the polymer has a glass transition temperature within a range of -50° C. to +100° C., a melting temperature within a range of 30° C. to 150° C., and a molecular weight (weight average basis) within a range of 3,000 to 100,000. The fixative is contained in a separate cartridge from the ink-jet ink print cartridge(s). The two-part fixative of the present invention comprises (1) a reactive monomer or oligomer in a vehicle, the reactive monomer or oligomer selected from the group consisting of iso-cyanates and epoxy-terminated oligomers, and (2) at least one second component selected from the group consisting of polyols, polyvinyl alcohols, and base catalysts. The reactive monomer or oligomer is contained in a separate cartridge from the ink-jet ink print cartridge(s), while the second component(s) is contained in at least one ink-jet ink print cartridge. The reactive monomer or oligomer reacts with the second component(s) on the print medium to form a polymer, which has a glass transition temperature within a range of -20° C. to +50° C. and a melting temperature within a range of 30° C. to 100° C. Enhancement of waterfastness, smearfastness, smudgefastness, and lightfastness is provided by use of the fixative solution of the present invention.

Description

[0001] The present invention is directed to ink-jet inks, and, more particularly, to fixer compositions used in ink-jet printing to enhance printing performance, such as smearfastness, smudge resistance, waterfastness, and lightfastness.[0002] There is a considerable demand in a better image quality of ink-jet. The low smearfastness, waterfastness, and lightfastness and the tendency to smudge seem to be the main drawbacks of ink-jet, and this invention addresses these issues.[0003] Several techniques has been used in the prior art to address these issues. One such technique is underprinting, which helps to stratify the colorant to the surface of the paper, reduce wicking, and improve color performance. Underprinting is defined as applying a transparent fluid on substrate prior the ink deposition. There are several patents addressing the technique of underprinting for better waterfastness and bleed control; see, e.g., U.S. Pat. No. 5,624,484, "Liquid Composition and Ink Set, and Imag...

AI Technical Summary

Benefits of technology

[0011] Enhancement of waterfastness, smearfastness, smudgefastness, and lightfastness, as well as print quality (optical density and chroma, for example), is provided by use of the fixative solution in the present invention.

Problems solved by technology

However, for dye-based inks, the underprinting techniques known in art only marginally increase, or, most often, decrease chroma.

Similarly, in the commercial Canon BJC-700 printer, underprinting improves the edge acuity and bleed, but decreases the color vividness (see Examples, below).

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