WO2003104341A1

WO2003104341A1 - Ink compositions containing ultraviolet absorbers

Info

Publication number: WO2003104341A1
Application number: PCT/US2001/023918
Authority: WO
Inventors: Ann P. Holloway; James F. Feeman
Original assignee: Lexmark International, Inc.
Priority date: 2001-05-10
Filing date: 2001-05-10
Publication date: 2003-12-18
Also published as: AU2001280902A1

Abstract

Ink compositions containing ultraviolet absorbing compounds of formula I wherein R₁, R₂ and R₃, are defined herein, and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group, or two -CO₂M groups. Ink jet ink compositions containing ultraviolet absorbing compounds of formula IV wherein R₂, R₃, R₄, R₅ and R₆ are defined herein, and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group or two -CO₂M groups, with the provision that either (1) R₂ and R₃ are not both hydrogen, or (2) R₅ is not hydrogen. The ink compositions are adapted for ink jet printing.

Description

INK COMPOSITIONS CONTAINING ULTRAVIOLET ABSORBERS

AnnP. Holioway James F. Feeman

FIELD OF THE INVENTION

The present invention relates to ink compositions, and more particularly, to ink compositions comprising ultraviolet absorbers. The ink compositions are particularly suitable for ink jet printing.

B CKGROUND OF THE INVENTION

Inkjet printing is accomplished by ejecting ink from a nozzle toward paper or another print medium. The ink may be driven toward the medium in a variety of ways. For example, in electrostatic printing, the ink is driven from a nozzle toward a medium by an electrostatic field. Another ink jet printing procedure, known as squeeze tube, employs a piezo-electric element in the ink nozzle. Electrically-caused distortions of the piezo-electric element pump the ink through the nozzle and toward the print medium. In still another ink jet printing procedure, known as thermal or bubble ink jet printing, the ink is driven from the nozzle toward the print medium by the formation of an expanding vapor phase bubble in the nozzle. These various printing methods are described in "Output Hard Copy Devices," edited by Durbeck and Sherr, Academic Press, 198S (see particularly Chapter 13, entitled, "Ink Jet Printing").

Ink compositions »ed in ink jet printers generally comprise deionized water, a water-soluble or water-miscible organic solvent, and a colorant. Generally, the colorant is a soluble dye or pigment Unfortunately, inks comprising soluble dyes or pigments can exhibit many problems, such as poor water-fastness, poor light-fastness, clogging of the jetting channels as a result of solvent evaporation and changes in the solubility of the dye, dye crystallization, poor ink quality including ink bleeding and feathering, poor thermal stability, chemical instability, and ease of oxidation.

The need for more light-fast inks for ink jet printing is increasing as photo images become mote popular. Resistance to lading due to light has been aided in industrial products by incorporation of ultraviolet absorbers (UV As). Commercially available UVAs are used in textile dying and for additives and coatings. To be effective, UVAs processed during textile dying typically require high temperature exposure for a duration of time; these high temperature requirements making the UVAs impractical for personal ink jet printing applications. UVAs used in the coating industry have limited solubility in water and therefore cannot be easily incorporated in conventional aqueous ink jet ink compositions.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an ultraviolet absorber that is water-soluble and can be easily and directly added into ink compositions, particularly ink compositions suitable for ink jet printing.

Other objects and advantages of the present invention will become apparent from the following disclosure,

In a first aspect, the present invention relates to an aqueous ink composition suitable for use in ink jet printers and comprising ink and a water-soluble ultraviolet absorbing compound of the formula \ N-Ri (I)

wherein R_{ is selected from the group consisting of

R_, is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; R₇ is selected from the group consisting of -H, -SO₃M and -NHCO-lower alkyl; Re is selected from the group consisting of -H, -CO₂M and -SO₃M; , is selected from the group consisting of -H, *CO₂M, -SO₃M and ^NHCO-lower alkyl; and M is selected from the group consisting of -H, -Na, - , -Li and -N-(R,₀)₄ wherein each R₁₀ is independently selected from the group consisting of -H, lower alkyl and CH CH-O)„-H.

I

R is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃', and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -C0₂M group, or two -CO₂M groups. In a second aspect, the present invention is directed to an ink jet print cartridge comprising an ink jet storage receptacle, an ink jet printhead and an ink jet ink

composition comprising ink and a water-soluble ultraviolet absorbing compound of the formula

wherein R, is selected from the group consisting of

R₂ is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; R_? is selected from the group consisting of -H, -S0₃ and -NHCO-lower alkyl; Rg is selected from the group consisting of -H, -CO₂M and -SO₃M; Rj, is selected from the group consisting of -H, -CO₂ , -SO₃M and -NHCO-lower alkyl; and M is selected from the group consisting of -H, -Na_ -K, -Li and -N-(R,₀)₄ wherein each R,₀ is independently selected from the group consisting of -H, lower alkyl and

-(CH₂-CH-O)^H;

I R„

R„ is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1

to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group, or two -CO₂M groups. Another aspect of the present invention comprises an aqueous ink composition comprising ink and a water soluble ultraviolet absorbing compound of the formula

wherein R₂ is selected from the group consisting of -H and halogen; R₃ is selected

from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -

SO₃M; , is selected from the group consisting of halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; R₅ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, and -OH; _$ is selected from the group consisting of -H, halogen,

lower alkyl, lower alkoxy, -CO₂M and »SO₃M; M is selected from the group consisting of -H, -Na, -Li and -N-(Rι₀)₄ wherein each R,„ is individually selected from the group consisting of -H, lo er alkyl and -(CH₂-CH-O)_π-H;

I

R_n is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -COjM group or two -CO₂M groups, with the provision that either (1) R₂ and R₃ are not both hydrogen, or (2) R₅ is not hydrogen.

The ink compositions of the present invention are advantageous in exhibiting

good color lightfastness when printed. The compositions are particularly advantageous for use in ink jet printers owing to the easy and direct combination of the aqueous ink and the water soluble ultraviolet absorber.

Still other objects, advantages and novel features of the present invention will become apparent to those skilled in the art from the following detailed description, which is simply by way of illustration various modes contemplated for carrying out the invention. As will be realized, the invention is capable of other different obvious aspects all without departing from the invention. Accordingly,.the description is illustrative in nature and not restrictive.

DETAILED DESCRIPTION

The present invention relates to ink jet ink compositions comprising ink and a water-soluble ultraviolet absorbent compound of the formula

wherein Rj is selected from the group consisting of

^ is selected from the group consisting of -H and halogen; R₃ is selected from the

group consisting of -H, halogen, lower alkyl, lower alkoxy, -C ₂M and -SO₃M; R₇ is selected from the group consisting of -H, -SO₃M and -NHCO-lower alkyl; Rg is

selected from the group consisting o -H, ~CO₂M and -SO₃M; R» is selected from the group consisting of -H, -CO₂M, -SO₃M and -NHCO-lower alkyl; and M is selected from the group consisting of -H, -Na, -K, -Li and -N-(R₁₀)₄ wherein each R,₀ is independently selected from the group consisting of -H, lower alkyl and

-(CH₂-CH-O)_n-H; i

R_π is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃ and

one -CO₂M group, or two -CO₂M groups.

Reference to lower alkyl throughout this specification refers to C,-C_β alkyl, preferably C,-C₄ alkyl. In addition, reference to lower alkoxy throughout this specification refers to C,-C₈ alkoxy, preferably C|-C₄ alkoxy.

Preferred ultraviolet absorbing compounds according to this embodiment of the present invention have the following structural formulas:

Another embodiment of the present invention comprises an ink composition

comprising ink and a water-soluble ultraviolet absorbing compound of the formula

wherein R_j is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -

SO_jM; R, is selected from the group consisting of halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; R, is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, and -OH; Re is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; M is selected from the group consisting of «H, -Na, -Li and -N-(R,₀)₄ wherein each R₁₀ is individually selected from the group consisting of -H, lower alkyl and -(CH₂-CH-O)_π-H;

R.

R„ is selected from the group consisting of -H, -CH, and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group or two -CO₂M groups, with the provision that either (1) R₂ and R₃ are not both hydrogen, or (2) R_s is not hydrogen.

Preferred ultraviolet absorbing compounds of the present invention have the following structural formulas

The ultraviolet absorbing compounds of this invention have been found to be

particularly efficacious in improving light-fastaess of prints made with ink jet printers

containing conventional dyes employed for such purposes including monoazo, poly- azo and copper phthalocyanine dyes. The ultraviolet absorbers of the present invention are highly water-soluble, readily dissolve in the usual aqueous vehicles employed in common ink jet compositions, and remain in solution upon extended

storage.

The ultraviolet absorbing compound is included in the ink compositions in an amount sufficient to improve the light-fastness of printed images. Preferably, the ink

compositions of the present invention comprise from about 0.1 to about 5% by weight

of the ultraviolet absorbing compounds. More preferably, the ink compositions

contain from about 1 to about 3% of the ultraviolet absorbing compounds. The

.ultraviolet absorbing compounds are preferably used in a salt form, which exhibits satisfactory water solubility. Examples of the salt form include sodium, potassium, lithium, ammonium, triethanolammonium, and tetramethylammonium salts, and

mixtures of various salt forms. The ultraviolet absorbent compounds are isolable in the free acid form and convertable to any of the salt forms, or alternatively, may be

synthesized directly in the desired salt form.

The ultraviolet absorbing compounds of the present invention may be prepared

by diazotizing and coupling an optionally substituted ortho-nitroaniline with a substituted phenol or naphthol which couples in the ortho position to the hydroxyl

group, and subsequently reducing the resultant ortho-nitro-ortho'-hydroxy-azo compound to the corresponding benzotriazole in alkaline aqueous medium using, for example, zinc, or more advantageously, hydrogen in the presence of a group VIII noble metal catalyst These reactions are well known to one of ordinary skill in the art and are more fully described in the chemical literature.

Suitable ortho-nitro anilines include, for example, 2-nitroaniline, 2- nitroaniIine-4-sulfonic acid, 4-amino-3-nitro-benzoic acid, 4-methyl-2-nitroaniline, 4- methoxy«2-nitroaniUne, 4-chloro-2-r_itroaniline, 5-chloro-2-nitroaniline, 4,5-dichloro-

2-nitroaniline, and 4-ethyl-2-nitroaniline, among others.

Suitable phenolic couplers include, for example, 4-hydroxybenzene sulfonic acid, guaiacol sulfonic acid, o-cresol-4-suIfonic acid, p-cresol, 2,4-dimethyl-ρhenol,

2-hydroxy-5-methyl<'benzoic acid, 4-hydroxy-benzoic acid, 2-hydroxy-5-methoxy-

benzoic acid, 4-methoxy-phenol, 4-chloro-phenol, 2,4-dichloro-ρhenol, and 3,4-

dichloro-phenol, among others. Examples of suitable naphthols include, for example, 2-naphthol, 2-naphthol- 4-sulfonic acid, 2-naphthol-6-sulfonic acid, 2-naphthol-8-sulfonic acid, 2-naphthol- 3,6-disulfonic acid, 2-naph.thol-6,8-disulfotuc acid, 2-naphthol-3-carboxylic acid, 2-

naphthol-6-carboxylic acid, l-naphthol-3,6-disulfonic acid, l-πaphthol-3-sulfonic acid, l-naphthol-4-sulfonic acid; l-naphthol-5-sulfonic acid, 2-acetamido-5-hydroxy-

naphthaIene-7-sulfonic acid, 2-acetømido-8-hydroxy-naphthalene-6-sulfonic acid, and

l-acetamido-8«hydroxy-naphthalene-3,6-disulfonic acid, among others.

The ink compositions of the present invention are aqueous compositions.

They contain at least 30% by weight of water, preferably deionized water. In addition to water, they may contain one or more water-miscible solvents, for example in an

amount of up to 70% by weight. Selection of a suitable carrier mixture depends on the requirements of the specific application involved, such as desired surface tension and viscosity, the selected pigment or dye, the desired drying time of the ink, and the type of paper onto which the ink will be printed. Representative examples of water soluble organic solvents that may be selected include (1) alcohols, such as methyl alcohol, ethyl alcohol, n-propyi alcohol, iso-prøpyl alcohol, n-butyl alcohol, sec-butyl alcohol, t-butyl alcohol, iso-butyl alcohol, furfuiyl alcohol, and tetrahydrofurfuryl alcohol; (2) ketones or ketoalcohols, such as acetone, methylethyl ketone and diacetone alcohol; (3) ethers, such as tetrahydrofuran and diσxane; (4) ethers, such as ethyl acetate, ethyl lactate, ethylene carbonate and propylene carbonate; (5) polyhydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol,

propylene glycol, tetraefheylene glycol, polyethylene glycol, glycerol, 2-methyl-2,4~

pentanedioL, 1,2,6-hexanetriol and thiodiglycol; (6) lower alkyl mono- or di-ethers derived from alkylene glycols, such as ethylene glycol monomethyl (or monoethyl)

ether, diethylene glycol monomethyl (or monoethyl) ether, propylene glycol

monomethyl (or monoethyl) ether, triethylene glycol monomethyl (or monoethyl) ether and diethylene glycol dimethy (or diethyl) ether; (7) nitrogen-containing cyclic

compounds, such as pyrrolidone, N-methyl-2-pyrrolidone and 1,3 -dimethy 1-2- imidazolidinone; and (8) sulfur-containing compounds, such as dimethyl sulfoxide and tetramethylene sulfone. Other useful organic solvents include lactones and

lactamJs.

Preferred water soluble organic solvents include polyhydric alcohols, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-

hexanetriol, thiodiglycol, hexylene glycol and diethylene glycol; diols, such as

butanediol, pentanediol, hexanediol and homologous diols; glycol ethers, such as propylene glycol laureate; glycerol; polyalkyl glycols, such as polyethylene glycol; and lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl or monoethyl ether, diethylene glycol methyl or ethyl ether, and triethylene glycol monomethyl or monoethyl ether. Particularly preferred organic solvents include ethylene glycol, diethylene glycol, and tetraethylene glycol.

In another embodiment of the present invention, the aqueous ink compositions

preferably comprise from about 0.5% to about 1 % by weight of an insoluble pigment, from about 0.1% to about S%, preferably from about 1% to about 3%, of an

ultraviolet absorbing compound as disclosed above, and an aqueous carrier.

A wide variety of organic and inorganic pigments, alone or in combination,

may be selected for use in the aqueous inks of the present invention. The key selection criteria for the pigment is that they must be dispersable in the aqueous

medium. The term "pigment," as used herein, means an insoluble colorant. The pigment particles are sufficiently small to permit free flow of the ink through the ink jet printing device, especially at the ejecting nozzles that usually have a diameter

ranging from about 10 microns to about 50 microns. The particle size also has an

influence on pigment dispersion stability, which is critical throughout the life of the ink. It is also desirable to use small particle:, for maximum color strength and gloss.

The range of useful particle size is from approximately 0.05 micron to approximately 15 microns. Preferably, the pigment particle size should range from about 0.05 micron to about 5 microns and most preferably, from about 0.05 micron to about 1 micron.

Pigments suitable for use in the present invention include, for example, azo pigments, such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments, polycyclic pigments, perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments,

isoindolinone pigments, quinophthalone pigments and dry lakes. Additional organic pigments include nitro pigments, nitroso pigments, aniline black and daylight

fluorescent pigments. Preferred pigments include titanium oxide, iron oxide, and

carbon black. Examples of commercially available pigments which may be used in the present invention include the following: Heliogen® Blue L 6901F (BASF),

Heliogen® Blue NBD 7010 (BASF), Heliogen® Blue 7090 (BASF),

Heucophtftai® Blue GXBT-583D (Heubach), Irgalite® Rubine 4 BL (Ciba-Gejgy),

Quindo® Magenta (Mobay), Indofast® Brilliant Scarlet (Mobay), Hostaperm® Scarlet GO (Hoechst), Permanent Rubine F6B (Hoechst), Monostral® Scarlet (Ciba- Geigy), Raven® 1170 (Col. Che .), Special Black 4A (Degussa), Black FW 18 (Degussa), Sterling® NS Black (Cabot), Sterlmg® NSX 76 (Cabot), Monarch® 880 (Cabot), Tipure® R-101 (DuPont), Mogul L (Cabot), BK 8200 (Paul Uhlich), Heliogen® Green K 8683 (BASF), Heliogen® Green L 9140 (BASF), Monostral®

Red B (Ciba-Geigy), Monastral® Violet R (Ciba-Geigy), Hostaperm® Orange GR (Hoechst), Paliogen® Orange (BASF), L75-2377 Yellow (Sun Chem,), L74-1357

Yellow (Sun Chem.), Hostaperm® Yellow H4G (Hoechst), Irgazin® Yellow 5GT (Ciba-Geigy), Permanent Yellow G3R-01 (Hoechst), Novoperm® Yellow FGL

(Hoechst), Chromophthal® Yellow 3G (Ciba-Geigy), Hansa Yellow X (Hoechst), Dalamar® Yellow YT-858-D (Heubach) and Hansa Brilliant Yellow 5GX-02 (Hoechst).

The ink compositions may also contain conventional amounts of various modifiers such as binders, surfactants, polymer dispersants, biocides, corrosion inhibitors, sequestrants, pH buffers, and/or conductivity addivitives. They may also contain ftirfher water-soluble ultraviolet light absorbers, if desired.

Another embodiment of the present invention comprises an ink jet print cartridge comprising an ink jet ink storage receptacle, an ink jet printhead and an ink jet ink composition comprising ink and a water-soluble ultraviolet absorbing

compound of the formula

wherein Rg is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -

SO₃M; R, is selected from the group consisting of halogen, lower alkyl, lower alkoxy,

-CO₂M and «SO₃M; R_s is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, and -OH; R_<. is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; M is selected from the group consisting of -H, -Na, -Li and -N-(R,₀)₄ wherein each R,₀ is individually selected from the group consisting of -H, lower alkyl and -(CH₂-CH-O)_n-H;

I R„

R_u is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group or two -CO₂M groups, with the provision (hat either (1) R₂ and R₃ are not hydrogen, or (2) R_j is not hydrogen.

Suitable ink jet ink storage receptacles and Inkjet printheads are disclosed, for example, in U.S. Patents Nos. 5,661,510, 5,751,324, 5,818,478 and 5,719,605, all of

which are incorporated herein by reference.

The following examples demonstrate various embodiments and advantages of

the ink compositions and ink jet print cartridges containing the ultraviolet absorbing compounds of the present invention. In the examples and throughout the present

specification, parts and percentages are by weight unless otherwise indicated. Example 1:

This example is directed to ink compositions of the present invention which

utilize the ultraviolet absorbing compound having the structural formula

The ink jet ink compositions were formulated using conventional ink jet inks comprising either sodium dye salts or tetramethylammonium (TMA) dye salt. A

yellow ink was formulated employing a tetramethylammonium (TMA) dye salt and 3% of the ultraviolet absorbing compound (V). Magenta and cyan inks were formulated using sodium dye salts and 3% of the ultraviolet absorbing compound (V). Comparative Inkjet compositions were formulated using conventional cyan, magneta and yellow inks without incorporating the 3% ultraviolet absorbing compound.

Light-fastness was measured by determining the delta E value between a control ink that has had no exposure to light and a sample that has been exposed to a Xenon Arc lamp for 48 hours. Therefore, the lower the delta E value, the better the light-fastness of the ink composition. Each of the ink compositions of the present invention and the comparative ink compositions of this example were used in ink jet recording on three different types of paper: plain (Xerox 4200), coated (Hi Res), and photo (Lexmark). Table 1 summarizes the delta E values for the ink jet ink compositions of the present invention and the comparative ink jet ink compositions.

As can be seen by the results in Table 1, the ink jet ink compositions comprising the ultraviolet absorbing compound showed dramatic improvement in light-fastness for most of the ink compositions in various paper types. Furthermore, the most dramatic improvement in light-fastness was demonstrated by the yellow ink containing the 3% ultraviolet absorbing compound. The yellow ink employs a tetramethylammonium (TMA) dye salt as compared to the sodium dye salts used in the magenta and cyan inks. Example 2:

This example is directed to ink jet ink compositions of the present invention comprising the ultraviolet absorbing compound having the following structural formula

Similar to the methods shown in Example 1, ink jet ink compositions were prepared using conventional ink jet inks and 3% of the ultraviolet absorbing compound VIII as shown above. Comparative ink jet ink compositions were formulated comprising the same ink jet inks without the 3% ultraviolet absorbing

compound. The yellow ink was prepared using a TMA dye salt while the magenta and cyan inks were prepared using sodium dye salts.

Similar to Example 1, the Inkjet ink compositions of the present invention and the comparative ink jet inks were then used in ink jet printing on the three types of paper as described in Example 1. Light-fastness of the ink jet ink compositions was then measured as described in Example 1. Table 2 details the delta E values for the present example.

Table 2

As shown in Table 2, the ink jet ink compositions of the present invention employing a 3% ultraviolet absorbing compound showed dramatically lower delta E values than (he comparative ink jet ink compositions. Therefore, the ink jet ink compositions of the present invention have superior light-fastness as compared to conventional ink jet ink compositions. It can be noted from Table 2 that the most dramatic improvement with the 3% ultraviolet absorbing compound was seen with the yellow ink. Exam le ?,

Inkjet ink compositions of the present invention which utilize the ultraviolet absorbing compound of Example 2 were formulated. Tetramethylammonium dye salts were employed in making the yellow, magenta and cyan inks. The tetramethylammonium dye salts were mixed with 3% of the ultraviolet absorbing compound to form yellow, magenta and cyan ink jet ink compositions. Comparative ink jet ink compositions were also prepared as detailed in Example 1. The ink jet ink compositions of the present invention and the comparative ink jet ink compositions were then used for Inkjet printing t measure light-fastness as described in Example 1. Table 3 details the results of this example.

Table 3

As shown in Table 3, ink jet ink compositions comprising the ultraviolet absorbing compounds of the present invention demonstrate improvements in light- fastness. Moreover, the most dramatic improvement in light-fastness was seen with the inkjet ink compositions comprising tetramethylammonium dye salts and the

ultraviolet absorbing compounds of the present invention. The examples demonstrate that the inkjet ink compositions according to the present invention exhibit surprising results in the improvement of Hght-fastoess over

conventional inkjet ink compositions.

The various preferred embodiments and examples set forth herein are presented in order to further illustrate the claimed invention and are not intended to be limiting thereof. Additional embodiments and alternatives within the scope of the claimed invention will be apparent to those of ordinary skill in the art.

Claims

What is claimed is:

1. An ink composition comprising ink and a water soluble ultraviolet absorbing compound of the formula

wherein R, is selected from the group consisting of

R₂ is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; , is selected from the group consisting of -H, -SO₃M and -NHCO-lower alkyl; R_g is selected from the group consistmg of -H, -CO₂M and -SO₃M; R^ is selected from the group consisting of -H, -CO₂M, -SO₃M and -NHCO-lower alkyl; and M is selected from the group consisting of -H, -Na, -K, -Li and -N-(R,₀)₄ wherein each R₎₀ is independently selected from the group consisting of -H, lower alkyl and (CH CH-OVH;

I

R_n

R_n is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group, or two *CO₂M groups.

2. The ink composition of claim 1. wherein R, is

The ink composition of claim 2, wherein R_g is -H,

4. The ink composition of claim 2, wherein R, is -SO₃M.

5. The ink composition of claim 3, wherein R_> is -SO₃M,

The ink composition of claim 2, wherein _$ is -H.

7. The ink composition of claim 2, wherein Rg is -CO₂M.

8. The ink composition of claim 5, wherein Itj is -H.

9. The ink composition of claim 8, wherein R₃ is -SO₃M.

10. The ink composition of claim 7, wherein j is -H,

11. The ink composition of claim 10, wherein R₃ is -SO₃M.

12, The ink composition of claim 1 , wherein R_} is

13. The ink composition of claim 12, wherein R_. is -H and R₃ is -H.

14. The ink composition of claim 12, wherein R_? is -SO₃M.

15. The ink composition of claim 13, wherein R_? is -SO₃M.

16. The ink composition of claim 13, wherein R, is -CO₂M.

17. The ink composition of claim 1 , wherein the ink comprises ammonium dye salt.

18. The ink composition of claim 17, wherein the ink comprises tetramethylammonium dye salt.

19. The ink composition of claim 2, wherein the ink comprises ammonium dye salt.

20. The ink composition of claim 1 , wherein the ink comprises

tetrametiiylammonium dye salt.

21. The ink composition of claim 12, wherein the ink comprises ammonium dye salt.

22. The ink composition of claim 21, wherein the ink comprises tetramemylammonium dye salt.

23. An inkjet print cartridge comprising an in jet ink storage receptacle, an ink jet printhead and an Inkjet ink composition comprising ink and a water soluble ultraviolet absorbing compound of the formula

wherein R, is selected from the group consisting of

R₂ is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; R₇ is selected from the group consisting of -H, -SO₃M and -NHCO-lower alkyl; R_g is selected from the group consisting of -H, -CO₂M and -SO₃M; R, is selected from the group consistmg of -H, -CO₂M, ~SO₃M and -NHCO-lower alkyl; and M is selected from the group consisting of -H, -Na, -K, -Li and -N-(R₁₀)₄ wherein each Rι₀ is independently selected from the group consisting of -H, lower alkyl and -(CH₂-CH-0)„-H;

I

R_n is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₂M group, or two -CO₂M groups.

24. An ink composition comprising ink and a water soluble ultraviolet absorbing compound of the formula

wherein R, is selected from the group consisting of -H and halogen; R₃ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and - SO₃M; R₄ is selected from the group consisting of halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; _$ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, and -OH; R^ is selected from the group consisting of -H, halogen, lower alkyl, lower alkoxy, -CO₂M and -SO₃M; M is selected from the group consisting of -H, -Na, -Li and -N-(R,₀)₄ wherein each R,₀ is individually selected from the group consisting of -H, lower alkyl and -(CH₂-CH-O)_n-H;

I

Rn R,_! is selected from the group consisting of -H, -CH₃ and -CH₂-CH₃; and n is from 1 to 4; and wherein the compound contains one or two -SO₃M groups, one -SO₃M and one -CO₃M group or two -CO₂M groups, with the provision that either (1) R_> and R₃ are not both hydrogen, or (2) Rj is not hydrogen.

25. The ink composition of claim 24, wherein the ink comprises ammonium dye

salt.

26. The ink composition of claim 25, wherein the ink comprises tetramethylammonium dye salt