Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1998-12-18
2001-08-21
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S100000, C347S105000, C347S095000
Reexamination Certificate
active
06276791
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing process for improving the light stability and wet abrasion resistance of an ink jet image formed from an aqueous ink containing a certain cationic 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 fades when exposed to light over a period of time, i.e., has poor light stability. The image also has poor wet abrasion resistance.
It is an object of this invention to provide an ink jet printing process for improving the light stability of an ink jet image formed from an aqueous ink containing a deprotonated cationic dye. It is another object of this invention to provide an ink jet printing process wherein a hardener is applied to improve wet abrasion resistance 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 applied can be precisely controlled independently of ink laydown and can be applied non-imagewise to the entire element.
SUMMARY OF THE INVENTION
These and other objects are achieved in accordance with the present invention which comprises an ink jet printing process for improving the light stability and wet abrasion resistance 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 polymer of gelatin or acetoacetylated poly(vinyl alcohol) and a mordant;
b) applying liquid ink droplets of a dye on the image-recording layer in an image-wise manner the dye being a water-soluble deprotonated cationic dye which is capable of being reprotonated to a cationic dye having a N—H group which is part of a conjugated system; and
c) applying an aqueous solution of an organic hardener to the image to cross-link the polymer.
It was found that when an aqueous solution containing a hardener is applied to a cationic dye-based ink image where the image-receiving layer has a cross-linkable polymer and a mordant, that the wet abrasion resistance and light stability of the image is improved.
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, and the laydown can be precisely controlled independent of ink laydown.
The hardeners employed in the invention 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.
The organic hardener that can be employed in the invention include 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-melamine 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; and
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.
Specific examples of hardeners useful in the process of the invention include the following:
Hardener 1: formaldehyde
Hardener 2: bis(vinyl sulfonylmethane) (Eastman Kodak Company)
Hardener 3: 2,3-dihydroxy-1,4-dioxane (Aldrich Chemical Co.)
Hardener 4: blocked hexamethylene diisocyanate (Bayer Co.)
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)
Hardener 11: phthaldehyde
Hardener 12: formaldehyde
In a preferred embodiment, the hardener employed in the invention is bis(vinyl sulfonylmethane), 2,3-dihydroxy-1,4-dioxane, glutaraldehyde or formaldehyde.
The aqueous hardener solution may be applied to the ink jet image in accordance with the invention in a non-imagewise manner either through a separate thermal or piezoelectric printhead, or by any other method which would apply the hardener solution evenly to the image, such as a spray bar or immersing the element in a bath of hardener. Methods of applying a hardener solution are disclosed in commonly-owned U.S. patent application Ser. No. 09/083,673 filed May 22, 1998, entitled “Printing Apparatus With Spray Bar For Improved Durability” of Wen et al. and U.S. patent application Ser. No. 09/083,876, filed May 22, 1998, entitled “Ink Jet Printing Apparatus With Print Head For Impro
Kovacs Csaba A.
Kung Teh-Ming
Romano, Jr. Charles E.
Barlow John
Cole Harold E.
Eastman Kodak Company
Shah M.
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