Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-01-26
2002-09-24
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S105000, C428S195100
Reexamination Certificate
active
06454404
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an inkjet printing process for improving the light stability and waterfastness of a printed image containing an inkjet ink containing a water-soluble anionic dye and a cationic receiver.
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. Inkjet 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.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-forming layer. The ink-receiving layer may be a polymer layer which swells to absorb the ink or a porous layer which imbibes the ink via capillary action.
Ink jet prints, prepared by printing onto ink jet recording elements, are subject to environmental degradation. They are especially vulnerable to water smearing, dye bleeding, coalescence and light fade. For example, since inkjet dyes are water-soluble, they can migrate from their location in the image layer when water comes in contact with the receiver after imaging. Highly swellable hydrophilic layers can take an undesirably long time to dry, slowing printing speed, and will dissolve when left in contact with water, destroying printed images. Porous layers speed the absorption of the ink vehicle, but often suffer from insufficient gloss and severe light fade.
U.S. Pat. No. 5,942,335 discloses an ink jet recording sheet comprising a support carrying an ink-receiving layer comprising a hydrophilic polymer and a polyvinylpyridine. However, there is a problem with this recording sheet in that images formed in the image-receiving layer have poor waterfastness.
U.S. Pat. No. 6,045,917 relates to the use of poly(N-vinyl benzyl-N, N, N-trimethyl ammonium chloride-co-ethyleneglycol dimethacrylate) particles in an ink jet image-recording layer. However, there is a problem with these particles in that images formed in the image-receiving layer have poor light stability, as will be shown hereafter.
It is an object of this invention to provide an inkjet printing method using anionic dyes suitable for use in aqueous inks for inkjet printing that will provide images with better light stability and waterfastness using certain receiver elements.
SUMMARY OF THE INVENTION
This 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 an image-receiving layer comprising a cationic, water-dispersible, partially quaternized pyridine-containing polymer,
C) loading the printer with an inkjet ink composition comprising water, a humectant, and a water soluble anionic dye; and
D) printing on the image receiving layer using the ink jet ink in response to the digital data signals.
It has been found that use of the above dyes and image-receiving layer provides excellent light stability and waterfastness.
DETAILED DESCRIPTION OF THE INVENTION
Any anionic, water-soluble dye may be used in composition employed in the method of the invention such as a dye having an anionic group, e.g., a sulfo group or a carboxylic group. The anionic, water-soluble 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-A1 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 composition employed in the method of 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. An example of an anionic dye which may be used in the invention is as follows:
The dyes described above may be employed in any amount effective for the intended purpose. In general, good results have been obtained when the dye is present in an amount of from about 0.2 to about 5% by weight of the ink jet ink composition, preferably from about 0.3 to about 3% by weight. Dye mixtures may also be used.
In a preferred embodiment of the invention, the cationic, water-dispersible, partially quaternized pyridine-containing polymer has the formula:
wherein:
each A independently represents a carbonyl group or a direct link, i.e., a bond;
each B independently represents O, NH or a direct link, i.e., a bond;
each R
1
independently represents H or CH
3
;
each R
2
independently represents an alkyl, cyclic alkyl or alkoxy group having from 1 to about 10 carbon atoms or a direct link, i.e., a bond;
R
3
represents a substituted or unsubstituted pyridine ring;
R
4
represents a substituted or unsubstituted pyridinium ring;
R
5
represents a linear, branched or cyclic alkyl, alkoxy or aryl group having from 1 to about 24 carbon atoms;
X represents an anion or a mixture of anions, such as halide (e.g., chloride or bromide), alkylsulfate (e.g. methylsulfate), alkylsulfonate (e.g. methylsulfonate), or arylsulfonate (e.g. benzenesulfonate or toluenesulfonate);
Z represents at least one ethylenically unsaturated monomer;
a represents a mole % of from about 0 to about 98;
b represents a mole % of from about 5 to about 98; and
c represents a mole % of from about 75 to about 2.
In a preferred embodiment of the invention, each R
1
represents H, each A, B and R
2
represents direct links, R
3
is pyridine and R
4
is pyridinium. In another preferred embodiment, R
5
is hydroxyethyl, a linear alkyl group having from about 12 to about 18 carbon atoms or benzyl.
As noted above, Z in the formula represents at least one ethylenically unsaturated, nonionic monomer. Examples of these include a styrene or an alpha-alkylstyrene, where the alkyl group has 1 to 4 carbon atoms and the aromatic group may be substituted or part of a larger ring system. Other examples of Z include acrylate esters derived from aliphatic alcohols or phenols; methacrylate esters; acrylamides; methacrylamides; N-vinylpyrrolidone or suitably substituted vinylpyrrolidones; vinyl esters derived from straight chain and branched acids, e.g., vinyl acetate; vinyl ethers, e.g., vinyl methyl eth
Lawrence Kristine B.
Teegarden David M.
Barlow John
Cole Harold E.
Eastman Kodak Company
Shah Manish S.
LandOfFree
Ink jet printing method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printing method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printing method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2882292