Improved ink compositions for thermal ink jet printing

Abstract: Disclosed is an ink composition which comprises water, a colorant, a bisquaternary ammonium compound, and a material of the formula [(F 3 C(F 2 C) n CH=CHCH 2 OCH(OH)CH 2 ) 2 NCH 2 COO - ][X + ], wherein X is a cation and n is an integer of from about 3 to about 20. Also disclosed are ink jet printing processes employing the aforementioned ink.

Description: The present invention is directed to ink compositions and to processes for the preparation and use thereof. More specifically, the present invention is directed to compositions suitable for use in ink jet printing processes. Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field which adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium. Since drop-on-demand systems require no ink recovery, charging, or deflection, the system is much simpler than the continuous stream type. There are two types of drop-on-demand ink jet systems. One type of drop-on-demand system has as its major components an ink filled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses. The relatively large size of the transducer prevents close spacing of the nozzles, and physical limitations of the transducer result in low ink drop velocity. Low drop velocity seriously diminishes tolerances for drop velocity variation and directionality, thus impacting the system's ability to produce high quality copies. Drop-on-demand systems which use piezoelectric devices to expel the droplets also suffer the disadvantage of a slow printing speed. The other type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets and allows very close spacing of nozzles. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information originate an electric current pulse in a resistive layer within each ink passageway near the orifice or nozzle, causing the ink in the immediate vicinity to evaporate almost instantaneously and create a bubble. The ink at the orifice is forced out as a propelled droplet as the bubble expands. When the hydrodynamic motion of the ink stops, the process is ready to start all over again. With the introduction of a droplet ejection system based upon thermally generated bubbles, commonly referred to as the "bubble jet" system, the drop-on-demand ink jet printers provide simpler, lower cost devices than their continuous stream counterparts, and yet have substantially the same high speed printing capability. The operating sequence of the bubble jet system begins with a current pulse through the resistive layer in the ink filled channel, the resistive layer being in close proximity to the orifice or nozzle for that channel. Heat is transferred from the resistor to the ink. The ink becomes superheated far above its normal boiling point, and for water based ink, finally reaches the critical temperature for bubble formation or nucleation of around 280°C. Once nucleated, the bubble or water vapor thermally isolates the ink from the heater and no further heat can be applied to the ink. This bubble expands until all the heat stored in the ink in excess of the normal boiling point diffuses away or is used to convert liquid to vapor, which removes heat due to heat of vaporization. The expansion of the bubble forces a droplet of ink out of the nozzle, and once the excess heat is removed, the bubble collapses on the resistor. At this point, the resistor is no longer being heated because the current pulse has passed and, concurrently with the bubble collapse, the droplet is propelled at a high rate of speed in a direction towards a recording medium. The resistive layer encounters a severe cavitational force by the collapse of the bubble, which tends to erode it. Subsequently, the ink channel refills by capillary action. This entire bubble formation and collapse sequence occurs in about 10 microseconds. The channel can be refired after 100 to 500 microseconds minimum dwell time to enable the channel to be refilled and to enable the dynamic refilling factors to become somewhat dampened. Thermal ink jet processes are well known and are described in, for example, U.S. Patent 4,601,777, U.S. Patent 4,251,824, U.S. Patent 4,410,899, U.S. Patent 4,412,224, and U.S. Patent 4,532,530. U.S. Patent 5,019,166 discloses a thermal ink jet printing composition comprising a dye, a liquid medium, and a surfactant selected from the group consisting of polyoxyalkylated ethers, anionic bitail fluorothio alkyls, alkyl aryl sulfonates, alkyl amine quaternary salts, and mixtures thereof. Also disclosed is a process for generating images which comprises causing the ink compositions disclosed herein to be ejected from a thermal ink jet printer in imagewise fashion onto a substrate. U.S. Patent 5,401,303 discloses a process wherein the halo effect seen at the interface between a first ink, exhibiting sharp edge acuity, and a second ink, having low surface energy, is addressed by adding certain fluorocarbon compounds to the first ink. Edge acuity of the first ink is maintained. While known compositions and processes are suitable for their intended purposes, a need remains for ink compositions with improved characteristics. In addition, a need remains for ink compositions which exhibit reduced or no intercolor bleed when printed adjacent to other inks of different colors. Further, a need remains for ink compositions having good latency characteristics. Additionally, there is a need for ink compositions with reduced viscosity. There is also a need for ink compositions which exhibit improved viscosity stability with respect to pH and temperature. In addition, there is a need for ink compositions with desirably low viscosities. Further, there is a need for ink compositions with good shelf stability. Additionally, there is a need for ink compositions which are compatible with sponge delivery in thermal ink jet printing hardware. A need further remains for ink compositions which do not interact or react adversely with the materials commonly used to fabricate thermal ink jet printheads. In addition, a need remains for ink compositions which enable the generation of prints on various papers with reduced or eliminated curling of the paper. Further, a need remains for ink compositions which enable uniform print quality over time. Additionally, a need remains for ink compositions which enable good overnight recoverability in thermal ink jet printing hardware. There is also a need for ink compositions which enable the generation of prints having vivid color. In addition, there is a need for ink compositions which exhibit improved waterfastness. Further, there is a need for ink compositions which exhibit improved lightfastness. Additionally, there is a need for ink compositions having dye colorants which exhibit reduced intercolor bleed with ink compositions having pigment colorants, whether or not the pigmented ink compositions contain a fluorinated material. A need also remains for ink compositions with improved color gamut. In addition, a need remains for ink compositions which exhibit reduced showthrough when printed on paper substrates. Further, a need remains for ink compositions suitable for printing onto a wide variety of substrates. Additionally, a need remains for ink compositions which are relatively benign with respect to any tendency to cause degradation of common thermal ink jet printhead materials. It is an object of the present invention to provide ink compositions with the above noted advantages. This object of the present invention (or specific embodiments thereof) can be achieved by providing an ink composition which comprises water, a colorant, a bisquatemary ammonium compound, and a material of the formula [(F 3 C(F 2 C) n CH=CHCH 2 OCH(OH)CH 2 ) 2 NCH 2 COO - ][X + ], wherein X is a cation and n is an integer of from 3 to 20. Inks of the present invention contain an aqueous liquid vehicle. The liquid vehicle can consist solely of water, or it can comprise a mixture of water and a water soluble or water miscible organic component, such as ethylene glycol, propylene glycol, diethylene glycols, glycerine, dipropylene glycols, polyethylene glycols, polypropylene glycols, tripropylene glycol monomethyl ether, amides, ethers, urea, substituted ureas, ethers, carboxylic acids and their salts, esters, alcohols, organosulfides, organosulfoxides, sulfones (such as sulfolane), alcohol derivatives, carbitol, butyl carbitol, cellusolve, ether derivatives, amino alcohols, ketones, N-methylpyrrolidinone, 2-pyrrolidinone, cyclohexylpyrrolidone, hydroxyethers, amides, sulfoxides, lactones, polyelectrolytes, methyl sulfonylethanol, imidazole, and other water soluble or water miscible materials, as well as mixtures thereof. When mixtures of water and water soluble or miscible organic liquids are selected as the liquid vehicle, the water to organic ratio typically ranges from 100:0 to 30:70, and preferably from 97:3 to 40:60. The non-water component of the liquid vehicle generally serves as a humectant which has a boiling point higher than that of water (100°C). In the ink compositions of the present invention, the liquid vehicle is typically present in an amount of from 60 to 95 percent by weight of the ink, and preferably from 70 to 90 percent by weight of the ink, although the amount can be outside these ranges. Also contained in the ink is a material of the formula wherein X + is a cation and n is an integer of from 3 to 20, preferably from 4 to 15, and more preferably from 5 to 11. Examples of suitable cations include (HO-CH 2 CH 2 ) 2 NH 2 + , (HO-CH 2 CH 2 ) 3 NH + , tris(hydroxymethyl)aminomethane hydrocitrate, protonated 1,4-diazabicyclo[2.2.2]octane, and the like. Materials of this formula are available from, for example, Ciba-Geigy, Ardsley, New York (Greensboro, NC) as LODYNE P-502, containing a mixture of compounds wherein n has varying values and has an average value of about 9. The material of this formula is present in the ink in any effective or desired amount; typically, the amount ranges from 0.1 to 10 percent by weight of the ink, preferably from 0.25 to 6 percent by weight of the ink, more preferably from 0.5 to 5 percent by weight of the ink, and even more preferably from 1 to 4 percent by weight of the ink, although the amount can be outside these ranges. Ink compositions of the present invention also contain a bisquaternary ammonium compound. Bisquaternary ammonium compounds suitable for the present invention include (but are not limited to) those of the general formula wherein each of R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 , independently of the others, is an alkyl group, preferably with from 1 to 6 carbon atoms (and wherein the alkyl group can be substituted with, for example, hydroxide groups, halide groups, or the like, R 7 is an alkylene group, preferably with from 2 to 10 carbon atoms (and wherein the alkylene group can be substituted with, for example, hydroxide groups, halide groups, or the like), and wherein A is an anion. Examples of suitable anions include (but are not limited to) hydroxide, halide, citrate, ethylene diamine tetraacetate, phosphite, and the like. Examples of suitable bisquatemary ammonium compounds include N,N'-hexamethylenebis(tributyl ammonium) compounds, N,N'-hexamethylenebis(trimethyl ammonium) compounds, and the like. Specific examples of suitable bisquatemary ammonium compounds include N,N'-hexamethylenebis(tributyl ammonium hydroxide), of the formula N,N'-hexamethylenebis(trimethyl ammonium bromide) (also called hexamethonium bromide), of the formula and the like. The bisquaternary ammonium compound is present in the ink in any desired or effective amount, typically in a stoichiometric amount of from 0.1 to 4 moles of bisquaternary ammonium compound per one mole of fluorinated material, preferably in a stoichiometric amount of from 0.25 to 2 moles of bisquatemary ammonium compound per one mole of fluorinated material, and more preferably in a stoichiometric amount of from 0.5 to 1 moles of bisquaternary ammonium compound per one mole of fluorinated material, although the relative amounts can be outside these ranges. The bisquatemary ammonium compound typically is present in the ink in an amount of from 0.1 to 10 percent by weight of the ink, and preferably from 0.5 to 4 percent by weight of the ink, although the amount can be outside these ranges. While not being limited to any particular theory, it is believed that the bisquaternary ammonium compound becomes associated with the fluorinated material (which has a carboxylic acid substituent) and imparts shelf stability to the ink. It is further hypothesized that the bisquaternary ammonium compound associated with the fluorinated material may reduce liposome lattice energy through ionic complexation, thereby arresting liposome growth and inhibiting phase separation in the ink composition. Additionally, it is hypothesized that the bisquatemary ammonium compound associated with the fluorinated material may increase the liposome radius of curvature, thereby stabilizing small liposomes relative to large liposomes (which may undesirably increase ink viscosity). In a preferred embodiment, the ink compositions of the present invention contain no imidazole. Imidazole is employed in some embodiments of the present invention to enhance the shelf stability of inks containing the fluorinated material. Since imidazole can cause degradation of many materials commonly used to fabricate thermal ink jet printheads, inks of this embodiment of the present invention are advantageously benign with respect to ink jet printhead materials. In another preferred embodiment, the ink compositions of the present invention contain tripropylene glycol monomethyl ether. When present, the tripropylene glycol monomethyl ether is present in any desired or effective amount, typically up to 15 percent by weight of the ink, and preferably up to 10 percent by weight of the ink, although the amount can be outside these ranges. This material is believed to function as a penetrant and also imparts shelf stability to the ink. In another particularly preferred embodiment of the present invention, the ink contains tripropylene glycol in combination with a polyethylene oxide additive. Also contained in the ink composition of the present invention is a colorant. Any suitable colorant can be employed, including dyes, pigments, mixtures thereof, and the like. Suitable dye or mixture of dyes compatible with the ink liquid vehicle include acid dyes, direct dyes, reactive dyes, and the like, with water soluble anionic dyes being preferred. The dye is present in the ink composition in any effective amount, typically from 0.5 to 15 percent by weight of the ink, and preferably from 1 to 10 percent by weight of the ink, although the amount can be outside of these ranges. Examples of preferred dyes for the inks of the present invention include Reactive Red 180 dye (commercially available as, for example, DUASYN BRILLIANT RED F3B SF VP 218 from Hoechst, Coventry, RI), Acid Red 52 dye (commercially available from, for example Tricon Colors, Elmwood Park, New Jersey), Acid Yellow 23 dye (commercially available as, for example, DUASYN ACID YELLOW XX-SF VP413 from Hoechst, Coventry, RI), Acid Yellow 17 dye (commercially available from, for example Tricon Colors, Elmwood Park, New Jersey), Acid Blue 9 dye, Direct Blue 199 dye (commercially available as, for example, PROJET CYAN 1 from Zeneca Colors, Dighton, Massachusetts), Direct Yellow 132 dye (commercially available as, for example, PROJET YELLOW 1G from Zeneca Colors, Dighton, Massachusetts), Reactive Red 180 dye (commercially available as, for example, PROJET MAGENTA 1T from Zeneca Colors, Dighton, Massachusetts), and mixtures thereof. In one embodiment, the ink contains a mixture of Reactive Red 180 dye and Acid Red 52 dye. In one particular embodiment containing this dye mixture, the ink further contains a mixture of betaine and butyl carbitol. In another particular embodiment containing this dye mixture, the ink further contains a mixture of tripropylene glycol monomethyl ether and a polymeric polyethylene oxide additive. In another embodiment, the ink contains a mixture of Acid Yellow 23 dye and Acid Yellow 17 dye. In one particular embodiment containing this dye mixture, the ink further contains a mixture of betaine and butyl carbitol. Inks of the present invention containing the fluorinated material and one or more of the above dye compositions exhibit excellent shelf stability as a result of the compatibility of these dyes with the fluorinated material. In addition, the inks exhibit good compatibility with printhead hardware, improved waterfastness and lightfastness, excellent optical density, and good color quality. Examples of suitable pigments for the inks of the present invention include various carbon blacks such as channel black, furnace black, lamp black, and the like. Colored pigments include red, green, blue, brown, magenta, cyan, and yellow particles, as well as mixtures thereof. Preferred particle average diameters are generally from 0.001 to 5 microns, and more preferably from 0.1 to 1 micron, although the particle size can be outside these ranges. Within the ink compositions of the present invention, the pigment is present in any effective amount to achieve the desired degree of coloration. Typically, the pigment is present in an amount of from 0.1 to 8 percent by weight of the ink, and preferably from 2 to 7 percent by weight of the ink, although the amount can be outside these ranges. In one particularly preferred embodiment, the ink contains a mixture of Reactive Red 180 dye (commercially available as, for example, DUASYN BRILLIANT RED F3B SF VP 218 from Hoechst, Coventry, RI), and Acid Red 52 dye (commercially available from, for example Tricon Colors, Elmwood Park, New Jersey). In one particular embodiment containing this dye mixture, the ink further contains a mixture of betaine and butyl carbitol. In another particular embodiment containing this dye mixture, the ink further contains a mixture of tripropylene glycol monomethyl ether and a polymeric polyethylene oxide additive. In another particularly preferred embodiment, the ink contains a mixture of Acid Yellow 23 dye (commercially available as, for example, DUASYN ACID YELLOW XX-SF VP413 from Hoechst, Coventry, RI) and Acid Yellow 17 dye (commercially available from, for example Tricon Colors, Elmwood Park, New Jersey). In one particular embodiment containing this dye mixture, the ink further contains a mixture of betaine and butyl carbitol. The ink compositions are generally of a viscosity suitable for use in thermal ink jet printing processes. At room temperature (i.e., about 25°C), typically, the ink viscosity is no more than 5 centipoise, and preferably is from 1 to 3 centipoise, although the viscosity can be outside this range. Ink compositions of the present invention can be of any suitable or desired pH. For some embodiments, such as thermal ink jet printing processes, typical pH values are from 8 to 9.5, preferably from 8.0 to 9.0, and more preferably from 8.5 to 9.0, although the pH can be outside of these ranges. The present invention is also directed to a process which entails incorporating an ink composition of the present invention into an ink jet printing apparatus and causing droplets of the ink composition to be ejected in an imagewise pattern onto a substrate. In a particularly preferred embodiment, the printing apparatus employs a thermal ink jet process wherein the ink in the nozzles is selectively heated in an imagewise pattern, thereby causing droplets of the ink to be ejected in imagewise pattern. Any suitable substrate can be employed, including plain papers such as Xerox® 4024 papers, ruled notebook paper, bond paper, silica coated papers such as Sharp Company silica coated paper, JuJo paper, and the like, transparency materials, fabrics, textile products, plastics, polymeric films, inorganic substrates such as metals and wood, and the like. In a preferred embodiment, the process entails printing onto a porous or ink absorbent substrate, such as plain paper. Specific embodiments of the invention will now be described in detail. All parts and percentages are by weight unless otherwise indicated. EXAMPLE I An ink composition was prepared by admixing the following ingredients: Ingredient Supplier Amount (grams) deionized water - - - 11.58 Acid Yellow 23 dye Hoechst 0.9 dipropylene glycol Ashland Chemicals 4.5 betaine FinnSugar Bioproducts 4.5 N,N'-hexamethylene bis(tributyl ammonium hydroxide) Aldrich Chemical Co. 1.02 LODYNE P-502 Ciba-Geigy 6.01 citric acid (10% by weight in water) Aldrich Chemical Co. 0.68 pH=8.0@25°C deionized water - - - 0.82 roll mill 30 minutes The ink composition thus prepared exhibited a viscosity of 6.56 centipoise at 25°C, a pH of 8.62 at 24.3°C, and a surface tension of 19.6 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE II An ink composition was prepared by admixing the following ingredients: The ink composition thus prepared exhibited a viscosity of 2.81 centipoise at 25°C, a pH of 8.90 at 25.4°C, a surface tension of 22.8 dynes per centimeter, and a conductivity of 6.85 millimhos. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE III An ink composition was prepared by admixing the following ingredients: The ink composition thus prepared exhibited a viscosity of 2.92 centipoise at 25°C, a pH of 8.85 at 25.5°C, a surface tension of 21.6 dynes per centimeter, and a conductivity of 3.85 millimhos. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE IV An ink composition was prepared by admixing the following ingredients: The ink composition thus prepared exhibited a viscosity of 2.97 centipoise at 25°C, a pH of 8.99 at 25.2°C, a surface tension of 23.8 dynes per centimeter, and a conductivity of 2.82 millimhos. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE V An ink composition was prepared by admixing the following ingredients: Ingredient Supplier Amount (grams) deionized water - - - 44.9 betaine FinnSugar Bioproducts 15 DOWICIL 150/200 Dow Chemical Co. 0.1 butyl carbitol Van Waters & Rogers 2 Reactive Red 180 dye Hoechst 3 Acid Red 52 dye Tricon Colors 5 deionized water - - - 5.94 sonicate 1 hour with stirring; setting=5; allowed to heat to 45°C 1,4-diazabicyclo[2.2. 2]octane Aldrich Chemical Co. 1.98 citric acid Aldrich Chemical Co. 0.78 hexamethonium bromide hydrate Aldrich Chemical Co. 1.32 LODYNE P-502 Ciba-Geigy 19.98 The resulting ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch. The ink composition thus prepared exhibited a viscosity of 2.49 centipoise at 25°C, a pH of 9.02 at 25°C, and a surface tension of 27.1 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE VI An ink composition was prepared by admixing the following ingredients: The resulting ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch. The ink composition thus prepared exhibited a viscosity of 2.15 centipoise at 25°C, a pH of 8.80 at 25°C, and a surface tension of 26.8 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE VII An ink composition was prepared by admixing the following ingredients: Ingredient Supplier Amount (grams) deionized water - - - 30.9 betaine FinnSugar Bioproducts 15 DOWICIL 150/200 Dow Chemical Co. 0.1 butyl carbitol Van Waters & Rogers 2 Acid Yellow 23 dye Hoechst 2 Acid Yellow 17 dye Tricon Colors 20 deionized water - - - 5.94 sonicate 1 hour with stirring; setting=5; water jacket cooled to 30°C 1,4-diazabicyclo[2.2. 2]octane Aldrich Chemical Co. 1.98 citric acid Aldrich Chemical Co. 0.78 hexamethonium bromide hydrate Aldrich Chemical Co. 1.32 LODYNE P-502 Ciba-Geigy 19.98 The resulting ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch. The ink composition thus prepared exhibited a viscosity of 2.52 centipoise at 25°C, a pH of 8.95 at 25°C, and a surface tension of 26.6 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE VIII To 59.4 grams of distilled water was added 19.8 grams of 1,4-diazabicyclo[2.2.2]octane (obtained from Aldrich Chemical Co., Milwaukee, WI, D2,780-2), 7.8 grams of citric acid (obtained from Aldrich Chemical Co., C8,315-5), 13.2 grams of hexamethonium bromide hydrate (obtained from Aldrich Chemical Co., 21,967-3), and 199.8 grams of LODYNE P-502 (containing 14.9 percent by weight of the fluorinated material, obtained from Ciba-Geigy, Ardsley, New York (Greensboro, NC)). The mixture was stirred for 15 minutes, after which time it exhibited a viscosity of 6.10 centipoise at 25°C. Thereafter, a 25 gram portion of the mixture was placed in a 30 gram vial. The vial was placed into a 550 SONIC DISMEMBRATOR (obtained from Fisher Scientific Co.) tuned at 20 kiloHertz and the LODYNE P-502 was subjected to ultrasonification for a period of 60 minutes at an amplitude setting of 5, with the power turned on and off every 30 seconds. The resulting colorless mixture had a viscosity of 3.57 centipoise at 25°C, a pH of 9.16 at 25°C, a conductivity of 7.62 millimhos, and a surface tension of 28.9 dynes per centimeter. EXAMPLE IX An ink composition was prepared by admixing the following ingredients: Ingredient Supplier Amount (grams) deionized water - - - 3.279 betaine FinnSugar Bioproducts 2.25 sarcosine Aldrich Chemical Co. 2.25 DOWICIL 150/200 Dow Chemical Co. 0.03 Acid Yellow 23 dye Hoechst 0.6 Acid Yellow 17 dye Tricon Colors 6.03 butyl carbitol Van Waters & Rogers 0.6 deionized water - - - 2.967 sonicate 1 hour with stirring; setting=5; allowed to heat to 50°C 1,4-diazabicyclo[2.2. 2]octane Aldrich Chemical Co. 0.99 citric acid Aldrich Chemical Co. 0.39 hexamethonium bromide hydrate Aldrich Chemical Co. 0.66 LODYNE P-502 Ciba-Geigy 9.99 The resulting ink composition exhibited a viscosity of 4.38 centipoise at 25°C, a pH of 8.83 at 25°C, and a surface tension of 21.3 dynes per centimeter. EXAMPLE X An ink composition was prepared by admixing the following ingredients: The resulting ink composition exhibited a viscosity of 3.04 centipoise at 25°C, a pH of 8.99 at 20°C, a conductivity of 7.36 millimhos, and a surface tension of 32.2 dynes per centimeter. EXAMPLE XI An ink composition was prepared as follows. To 46.4 grams of deionized water were added 0.167 gram of DOWICIL 150/200 biocide (obtained from Dow Chemical Co., Midland, Ml), 0.0833 gram of polyethylene oxide (bisphenol-A derivative, of the formula molecular weight 18,500, obtained from Polysciences Corp.), 20.00 grams of tripropyleneglycol monomethylether (DOWANOL TPM, obtained from Dow Chemical Co.), 41.67 grams of PROJET MAGENTA 1T dye solution (dye solution contained 10 percent by weight dye solids, obtained from Zeneca Colors, Dighton, Massachusetts), 8.33 grams of Acid Red 52 dye solution (dye solution contained 10 percent by weight dye solids, obtained from Tricon Colors, Elmwood Park, New Jersey), and an additional 9.90 grams of deionized water. The mixture thus prepared was then sonified by the process described in Example VIII. To the mixture were then added 3.30 grams of 1,4-diazabicyclo[2.2.2]octane (obtained from Aldrich Chemical Co., D2,780-2, Milwaukee, WI), 1.3 grams of citric acid (obtained from Aldrich Chemical Co.), 2.2 grams of hexamethonium bromide hydrate (obtained from Aldrich Chemical Co., 21,967-3), and 33.3 grams of LODYNE P-502 (solution containing 14.9 percent by weight fluorocarbon material, obtained from Ciba-Geigy, Ardsley, New York (Greensboro, NC)). The resulting magenta ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch over a period of 55 seconds. The ink composition thus prepared exhibited a viscosity of 4.34 centipoise at 25°C, a pH of 8.56 at 25°C, a conductivity of 8.46 millimhos, and a surface tension of 24.6 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE XII An ink composition was prepared as described in Example XI except that the initial amount of deionized water was 38.1 grams (and not 46.4 grams) and that 58.33 grams of PROJET CYAN 1 dye solution (dye solution contained 10 percent by weight dye solids, obtained from Zeneca Colors, Dighton, Massachusetts) was substituted for the PROJET MAGENTA 1T and Acid Red 52 dyes. The resulting cyan ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch over a period of 65 seconds. The ink composition thus prepared exhibited a viscosity of 3.72 centipoise at 25°C, a pH of 8.79 at 25°C, a conductivity of 7.07 millimhos, and a surface tension of 18.8 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5. EXAMPLE XIII An ink composition was prepared as described in Example XI except that the initial amount of deionized water was 38.1 grams (and not 46.4 grams) and that 33.3 grams of PROJET YELLOW 1G dye solution (dye solution contained 7.5 percent by weight dye solids, obtained from Zeneca Colors, Dighton, Massachusetts) and 25.0 grams of Acid Yellow 17 dye (dye solution contained 10 percent by weight dye solids, obtained from Tricon Colors, Elmwood Park, New Jersey) were substituted for the PROJET MAGENTA 1T and Acid Red 52 dyes. The resulting cyan ink composition was then filtered through a 1.2 micron 47 mm Gelman filter at 10 pounds per square inch over a period of 50 seconds. The ink composition thus prepared exhibited a viscosity of 4.46 centipoise at 25°C, a pH of 8.62 at 25°C, a conductivity of 7.81 millimhos, and a surface tension of 20 dynes per centimeter. The ink composition thus prepared was then incorporated into a Hewlett-Packard 1600C thermal ink jet printer and printed onto Xerox® 4024 DP paper and Xerox® Image Series Elite paper. The prints thus formed exhibited low intercolor bleed with a MFLEN value of 5.

Claims: An ink composition which comprises water, a colorant, a bisquatemary ammonium compound, and a material of the formula [(F 3 C(F 2 C) n CH=CHCH 2 OCH(OH)CH 2 ) 2 NCH 2 COO - ][X + ], wherein X is a cation and n is an integer of from 3 to 20. The ink composition according to claim 1 wherein the bisquatemary ammonium compound is present in an amount of from 0.1 to 10 percent by weight of the ink. The ink composition according to claim 1 wherein the material of the formula [(F 3 C(F 2 C) n CH=CHCH 2 OCH(OH)CH 2 ) 2 NCH 2 COO - ][X + ] is present in an amount of from 0.1 to 10 percent by weight of the ink. The ink composition according to claim 1 wherein X is selected from the group consisting of (HO-CH 2 CH 2 ) 2 NH 2 + , (HO-CH 2 CH 2 ) 3 NH + , tris(hydroxymethyl)aminomethane hydrocitrate, protonated 1,4-diazabicyclo[2.2.2]octane, and mixtures thereof. The ink composition according to claim 1 wherein the bisquaternary compound is selected from the group consisting of N,N'-hexamethylenebis(tributyl ammonium hydroxide), N,N'-hexamethylenebis(trimethyl ammonium bromide), and mixtures thereof. The ink composition according to claim 1 wherein the ink also contains betaine. The ink composition according to claim 6 wherein the ink also contains dipropylene glycol. The ink composition according to claim 6 wherein the ink also contains butyl carbitol. A process which comprises (i) incorporating into an ink jet printing apparatus an ink composition comprising water, a colorant, bisquatemary ammonium compound, and a material of the formula [(F 3 C(F 2 C) n CH=CHCH 2 OCH(OH)CH 2 ) 2 NCH 2 COO - ][X + ], wherein X is a cation and n is an integer of from 3 to 20; and (ii) causing droplets of the ink composition to be ejected in an imagewise pattern onto a substrate. The process according to claim 9 wherein the printing apparatus employs a thermal ink jet process wherein the ink in the nozzles is selectively heated in an imagewise pattern, thereby causing droplets of the ink to be ejected in imagewise pattern.

Inventors: COLT RICHARD L, GUNDLACH KURT B, MCGRATH RACHEL L, SANCHEZ LUIS A, COLT, RICHARD L., GUNDLACH, KURT B., MCGRATH, RACHEL L., SANCHEZ, LUIS A.
Applicants: XEROX CORP, XEROX CORPORATION
Application year: 1998
Main classification: C09D11
IPC codes: C09D11, B41J2, B41M5