Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
1998-12-18
2001-01-09
Hilten, John S. (Department: 2854)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S105000, C427S337000, C427S258000
Reexamination Certificate
active
06170944
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing process for improving the water-fastness of an ink jet image formed from an aqueous ink containing an anionic dye.
BACKGROUND OF THE INVENTION
Ink jet printing is a non-impact method for producing images by the deposition of ink droplets in a pixel-by-pixel manner to an image-recording element in response to digital signals. There are various methods which may be utilized to control the deposition of ink droplets on the image-recording element to yield the desired image. In one process, known as continuous ink jet, a continuous stream of droplets is charged and deflected in an imagewise manner onto the surface of the image-recording element, while unimaged droplets are caught and returned to an ink sump. In another process, known as drop-on-demand ink jet, individual ink droplets are projected as needed onto the image-recording element to form the desired image. Common methods of controlling the projection of ink droplets in drop-on-demand printing include piezoelectric transducers and thermal bubble formation. 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 the various ink jet printers can be classified as either dye-based or pigment-based. A dye is a colorant which is molecularly dispersed or solvated by a carrier medium. The carrier medium can be a liquid or a solid at room temperature. A commonly used carrier medium is water or a mixture of water and organic co-solvents. Each individual dye molecule is surrounded by molecules of the carrier medium. 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 medium, such inks also generally suffer from poor water-fastness.
DESCRIPTION OF RELATED ART
JP
10-219157
relates to an ink jet ink comprising an aqueous medium, a colorant and a very small amount of glutaraldehyde as a biocide.
There is a problem with using this ink, however, in that when it is printed on an image-recording element, the resultant image has poor water-fastness.
It is an object of this invention to provide an ink jet printing process for improving the water-fastness of an ink jet image formed from an aqueous ink containing an anionic dye. It is another object of this invention to provide an ink jet printing process wherein a hardener is applied to improve the water-fastness of the ink jet image. It is another object of the invention to provide an ink jet printing process where the laydown of the hardener can be applied non-imagewise to the entire element.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an ink jet printing process for improving the water-fastness of an ink jet image comprising:
a) providing an ink jet recording element comprising a support having thereon an image-recording layer comprising a cross-linkable gelatin and a mordant,
b) applying liquid ink droplets of an anionic, water-soluble dye on the image-recording layer in an image-wise manner, and
c) submerging the element in an aqueous solution of a hardener to cross-link the gelatin.
It was found that the water-fastness of the image is improved with this treatment with a hardener solution.
DETAILED DESCRIPTION OF THE INVENTION
This process offers an advantage over incorporating a hardener in an ink since the hardener can be applied in both imaged and non-imaged areas.
Any hardener can be used in the invention provided it cross-links the cross-linkable gelatin employed. Hardeners may be used at concentrations ranging from 0.10 to 5.0 weight percent of active ingredient in the aqueous solution, preferably 0.25 to 2.0 weight percent.
The aqueous hardener solution may also contain, if desired, co-solvents, humectants, surfactants, and other ingredients commonly added to ink jet inks.
Examples of hardeners that can be employed in the invention fall into several different classes such as the following (including mixtures thereof):
a) formaldehyde and compounds that contain two or more aldehyde functional groups such as the homologous series of dialdehydes ranging from glyoxal to adipaldehyde including succinaldehyde and glutaraldehyde; diglycolaldehyde; aromatic dialdehydes, etc.;
b) blocked hardeners (substances usually derived from the active hardener that release the active compound under appropriate conditions) such as substances that contain blocked aldehyde functional groups, such as tetrahydro-4-hydroxy-5-methyl-2(1H)-pyrimidinone polymers, polymers of the type having a glyoxal polyol reaction product consisting of 1 anhydroglucose unit: 2 glyoxal units, dimethoxylethanal-melarnine non-formaldehyde resins, 2,3-dihydroxy-1,4-dioxane, blocked dialdehydes and N-methylol compounds obtained from the condensation of formaldehyde with various aliphatic or cyclic amides, ureas, and nitrogen heterocycles;
c) active olefinic compounds having two or more olefinic bonds, especially unsubstituted vinyl groups, activated by adjacent electron withdrawing groups, such as divinyl ketone; resorcinol bis(vinylsulfonate); 4,6-bis(vinylsulfonyl)-m-xylene; bis(vinylsulfonylalkyl) ethers and amines; 1,3,5-tris(vinylsulfonyl) hexahydro-s-triazine; diacrylamide; 1,3-bis(acryloyl)urea; N,N′-bismaleimides; bisisomaleimides; bis(2-acetoxyethyl) ketone; 1,3,5-triacryloylhexahydro-s-triazine; and blocked active olefins of the type bis (2-acetoxyethyl) ketone and 3,8-dioxodecane-1,10-bis(pyridinium perchlorate) bis(vinyl sulfonylmethane), bis(vinyl sulfonylmethyl ether), and the like;
d) compounds that contain two or more amino groups such as ethylene diamine; and
e) inorganic salts such as aluminum sulfate; potassium and ammonium alums of aluminum; ammonium zirconium carbonate; chromium salts such as chromium sulfate and chromium alum; and salts of titanium dioxide, zirconium dioxide, etc.
Specific examples of hardeners useful in the invention include the following:
Hardener 1: aluminum sulfate
Hardener 2: bis(vinyl sulfonylmethane) (Eastman Kodak Company)
Hardener 3: 2,3dihydroxy-1,4-dioxane (Aldrich Chemical Co.)
Hardener 4: ethylene diamine
Hardener 5: glyoxal
Hardener 6: bis(vinyl sulfonylmethyl ether) (Eastman Kodak Company)
Hardener 7: glutaraldehyde
Hardener 8: a glyoxal polyol reaction product consisting of 1 anhydroglucose unit:2 glyoxal units, SEQUAREZ® 755 (Sequa Chemicals, Inc.)
Hardener 9: a cyclic urea glyoxal condensate consisting of 1 cyclic urea unit: 1 glyoxal unit, SUNREZ® 700M (Sequa Chemicals, Inc.)
Hardener 10: dimethoxylethanal-melamine non-formaldehyde resin, Sequa CPD3086-100 (Sequa Chemicals, Inc)
Any anionic, water-soluble dye may be used in the invention such as a dye having an anionic group, e.g., a sulfo group or a carboxylic group. The anionic dye may be any acid dye, direct dye or reactive dye listed in the COLOR INDEX but is not limited thereto. Metallized and non-metallized azo dyes may also be used as disclosed in U.S. Pat. No. 5,482,545, the disclosure of which is incorporated herein by reference. Other dyes which may be used are found in EP 802246-A 1 and JP 09/202043, the disclosures of which are incorporated herein by reference. In a preferred embodiment, the anionic, water-soluble dye which may be used in the invention is a metallized azo dye, a non-metallized azo dye, a xanthene dye, a metallophthalocyanine dye or a sulfur dye. Mixtures of these dyes may also be used. The dye may be present in an amount of from about 0.1 to about 10% by weight, preferably from about 0.25 to about 3% by weight.
Any mordant can be used in the invention provided it produces the desired result of fixing the anionic dye. For example, there may be used a cationic polymer, e.g., a polymeric quartenary ammonium compound, or a basic polymer, such as poly(dimethylaminoethyl)methacrylate, polyalkylenepolyamines, and products of
Gallo Elizabeth A.
Romano, Jr. Charles E.
Cole Harold E.
Eastman Kodak Company
Grohusky Leslie J.
Hilten John S.
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