Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-12-20
2003-01-21
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
Reexamination Certificate
active
06508548
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing method which employs a porous receiver and an ink jet composition which provides improved stability to light and other environmental contaminants such as ozone.
BACKGROUND OF THE INVENTION
Ink jet printing is a non-impact method for producing images by the deposition of ink droplets on a substrate (paper, transparent film, fabric, etc.) in response to digital signals. Ink jet printers have found broad applications across markets ranging from industrial labeling to short run printing to desktop document and pictorial imaging. The inks used in ink jet printers are generally classified as either dye-based or pigment-based.
A dye is a colorant which is molecularly dispersed or solvated by a carrier. The carrier can be a liquid or a solid at room temperature. A commonly used carrier is water or a mixture of water and organic co-solvents. Each individual dye molecule is surrounded by molecules of the carrier. In dye-based inks, no particles are observable under the microscope. Although there have been many recent advances in the art of dye-based ink jet inks, such inks still suffer from deficiencies such as low optical densities on plain paper and poor light-fastness. When water is used as the carrier, such inks also generally suffer from poor water fastness.
Ozone is generally present in the air at sea level at concentration of about 10 to 50 parts per billion. Under certain conditions, the ozone concentration even exceeds those levels. However, even at the low ozone concentration, dyes such as ink jet dyes can be very sensitive and fade significantly when the air permeability of a receiver is high.
U.S. Pat. No. 4,460,637 relates to a porous ink jet receiver element. However, there is a problem with this element in that when it is printed using a conventional aqueous dye-based ink, the printed image has poor stability to light and other environmental contaminants such as ozone.
JP 08-259863A relates to an ink jet ink composition comprising a water-soluble dye and resin microparticles. However, there is a problem with this ink in that when it is printed onto a conventional, nonporous receiver, the dry time is slow.
It is an object of this invention to provide an ink jet printing method which provides a print having an image which has a fast dry time. It is another object of this invention to provide an ink jet printing method which provides a print having an image which has improved ambient light and ozone stability.
SUMMARY OF THE INVENTION
These and other objects are achieved in accordance with this invention which relates to an ink jet printing method, comprising the steps of:
A) providing an ink jet printer that is responsive to digital data signals;
B) loading the printer with ink-receptive elements comprising a support having thereon a porous ink-receptive layer;
C) loading the printer with an ink jet ink composition comprising a water-dispersible polymeric latex and a water soluble dye; and
D) printing on an ink-receptive substrate using the ink jet ink in response to the digital data signals.
DETAILED DESCRIPTION OF THE INVENTION
The support for the ink-receptive element employed in the invention can be paper or resin-coated paper, plastics such as a polyester-type resin such as poly(ethylene terephthalate), polycarbonate resins, polysulfone resins, methacrylic resins, cellophane, acetate plastics, cellulose diacetate, cellulose triacetate, vinyl chloride resins, poly(ethylene naphthalate), polyester diacetate, various glass materials, etc. The thickness of the support employed in the invention can be, for example, from about 12 to about 500 &mgr;m, preferably from about 75 to about 300 &mgr;m.
In a preferred embodiment of the invention the porous ink-receptive layer contains inorganic particles such as silica, alumina, titanium dioxide, clay, calcium carbonate, barium sulfate, or zinc oxide. In another preferred embodiment, the porous ink-receptive layer comprises from about 20% to about 90% inorganic particles and from about 10% to about 80% polymeric binder, such as gelatin, poly(vinyl alcohol), poly(vinyl pyrrolidinone) or poly(vinyl acetate). The porous ink-receptive layer can also contain polymer micro-porous structures without inorganic filler particles as shown in U.S. Pat. Nos. 5,374,475 and 4,954,395, the disclosures of which are hereby incorporated by reference.
A broad range of water-soluble dyes can be used in this invention, such as reactive dyes, direct dyes, anionic dyes, acid dyes, food dyes and the like, such as those described in U.S. Pat. No. 5,973,026, the disclosure of which is hereby incorporated by reference. In a preferred embodiment of the invention the water-soluble dye may be a cationic or an anionic dye.
Examples of cationic dyes which may be used are azo dyes, such as a quarternized pyrazoleazoaniline dye as disclosed in U.S. patent application Ser. No. 09/643,281, filed Aug. 22, 2000, the disclosure of which is hereby incorporated by reference; triarylmethane dyes; azine dyes; phthalocyanine dyes; oxazine dyes or thiazine dyes.
Examples of anionic dyes which may be used are metal-complex dyes, such as transition metal complexes of 8-heterocyclylazo-5-hydroxyquinoline; azo dyes, such as C.I. Direct Yellow 132; phthalocyanine dyes such as C.I. Direct Blue 199; anthraquinone dyes, or anthrapyridone dyes. U.S. Pat. No. 6,183,548, filed Aug. 31, 1999 of Erdtmann et al. discloses examples of the above dyes.
The water-soluble dye used in method of the invention is present in the ink jet ink in any effective amount, generally from about 0.1 to about 10% by weight, and preferably from about 0.5% to about 6% by weight.
The ink jet ink containing the water-dispersible polymeric latex employed in the invention consists of water as a continuous phase and polymeric latex as a dispersed phase. The water-soluble dye and the water dispersible polymeric latex are present in the ink so that the water-soluble dye and the water dispersible latex exist either individually or are physically mixed. In a preferred embodiment of the invention, the polymeric latex meets the following test: At 25° C., the polymeric latex must: (a) be capable of forming a stable dispersion with water at a concentration of from 0.2 to 50 percent by weight, preferably 1 to 20 percent by weight, and (b) when 100 ml of the latex is then mixed in an equal volume of the water-miscible organic solvent described above, stirred and allowed to stand for 10 minutes exhibit no observable coagulation of the polymeric latex. In general, the latex should have an average particle size of <1 &mgr;m, preferably <0.5 &mgr;m, more preferably <0.05 &mgr;m.
The water-dispersible polymeric latex used in this invention are generally hydrophobic polymers of any composition that can be stabilized in an water-based medium. Such hydrophobic polymers are generally classified as either condensation polymer or addition polymers. Condensation polymers include, for example, polyesters, polyamides, polyurethanes, polyureas, polyethers, polycarbonates, polyacid anhydrides, and polymers comprising combinations of the above-mentioned types. Addition polymers are polymers formed from polymerization of vinyl-type monomers including, for example, allyl compounds, vinyl ethers, vinyl heterocyclic compounds, styrenes, olefins and halogenated olefins, unsaturated acids and esters derived from them, unsaturated nitrites, vinyl alcohols, acrylamides and methacrylamides, vinyl ketones, multifunctional monomers, or copolymers formed from various combinations of these monomers.
The water-dispersible polymeric latex can be prepared in aqueous media using well-known free radical emulsion polymerization methods and may consist of homopolymers made from one type of the above-mentioned monomers or copolymers made from more than one type of the above-mentioned monomers. Polymers comprising monomers which form water-insoluble homopolymers are preferred, as are copolymers of such monomers. Preferred polymers may also comprise monomers which give water-soluble homopo
Chen Huijuan D.
Erdtmann David
Yau Hwei-Ling
Barlow John
Brooke Michael S.
Cole Harold E.
Eastman Kodak Company
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