Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2001-10-31
2003-06-17
Hess, Bruce H. (Department: 1774)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C428S195100
Reexamination Certificate
active
06578960
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing process for improving the Dmax density and light stability of an ink jet printed image containing a water-soluble 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 that 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 that 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 that swells to absorb the ink or a porous layer that 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 ink jet 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 or fade induced by atmospheric ozone.
U.S. Pat. No. 4,926,190 relates to the use of UV-absorbers in a recording material. However, there is a problem with these materials in that they are not polymeric and may tend to wander out of the layer.
U.S. Pat. No. 5,384,235 relates to the use of polymeric UV-absorbers in a silver halide color photographic element. However, there is no disclosure in this patent of the use of these materials in an ink jet recording system.
U.S. Pat. No. 6,045,917 relates to the use of cationic mordants in an ink jet image-recording layer. However, there is a problem with this element in that images formed in the image-receiving layer have poor light stability, as will be shown hereafter.
U.S. patent application Ser. No. 09/611,123, filed Jul. 6, 2000, relates to the use of stabilizers in an ink jet receiver for improved light stability. However, it would be desirable to improve the light stability of images formed in the image-receiving layer of this element.
It is an object of this invention to provide an ink jet printing method using anionic dyes suitable for use in aqueous inks for ink jet printing that will provide images with better Dmax density and light stability.
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 an ink jet recording element comprising a support having thereon the following layers in order:
i) a base layer comprising a polymeric binder, a polymeric mordant and a stabilizer having the following formula:
wherein:
each R individually represents a substituted or unsubstituted alkyl or alkoxy group having from about 1 to about 7 carbon atoms, a phenyl group having from about 6 to about 10 carbon atoms; a phenoxy group having from about 6 to about 10 carbon atoms; a carbonamido group having from about 1 to about 8 carbon atoms; or two or more R groups can be combined together to form a ring structure;
n is 1 to 4;
L is a linking group containing at least one carbon atom; and
M
+
is a monovalent cation,
with the proviso that the total number of carbon atoms in all the R's and L taken together is at least 3, and at least one R is an alkoxy group; and
ii) an overcoat layer comprising a polymeric UV-absorbing material;
C) loading said printer with an ink jet ink composition comprising water, a humectant, and a water-soluble dye; and
D) printing on said overcoat layer using said ink jet ink in response to said digital data signals.
It has been found that use of the above dyes and image-receiving layer provides excellent Dmax density and light stability.
DETAILED DESCRIPTION OF THE INVENTION
Any 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. Examples of dyes that may be used in the invention are 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 polymeric UV-absorbing material comprises the following repeating units:
wherein:
R
1
represents H or CH
3
;
R
2
represents H, halogen, alkoxy or a straight chain or branched alkyl group having from 1 to about 8 carbon atoms;
R
3
represents H, Cl, alkoxy or an alkyl group having from 1 to about 4 carbon atoms;
X represents COO, CONH or aryl; and
Y represents an alkylene group having from about 2 to about 10 carbon atoms or (CH
2
)
m
O wherein m is 1 to about 4.
Specific examples of polymeric UV-absorbing repeating units useful in the invention include the following:
TABLE 1
UV-
Absorber
R
1
R
2
R
3
X
Y
UV-1
CH
3
H
H
COO
(CH
2
)
2
UV-2
H
H
Cl
COO
(CH
2
)
3
UV-3
H
H
H
CH
2
O
UV-4
CH
3
C(CH
3
)
3
H
COO
(CH
2
)
3
UV-5
H
CH
3
H
CONH
CH
2
UV-6
H
CH
3
OCH
3
CONH
CH
2
UV-7
H
C(CH
3
)
3
Cl
CONH
CH
2
UV-8
CH
3
H
H
COO
(CH
2
)
2
OCONH
UV-9
CH
3
Cl
H
COO
UV-10
CH
3
H
Cl
COO
(CH
2
)
3
UV-11
H
H
Cl
COO
(CH
2
)
3
UV-12
CH
3
H
Cl
COO
UV-13
H
H
Cl
COO
UV-14
CH
3
H
Cl
COO
UV-15
H
C
Lawrence Kristine B.
Merkel Paul B.
Cole Harold E.
Eastman Kodak Company
Grendzynski Michael
Hess Bruce H.
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