Abstract: A continuous ink jet printer aqueous ink composition including pigment particles dispersed with a dispersant or self dispersing pigment particles without the need for a dispersant, and a polymer additive distinct from any dispersant used to disperse the pigment particles, wherein the polymer additive comprises a styrene-acrylic copolymer that does not substantially displace any dispersant used to disperse the pigment, present in an amount effective to stabilize the ink composition against shear induced agglomeration caused by pumping the ink composition through a continuous ink jet printing fluid system.

Abstract: The invention relates to continuous ink jet printing of an aqueous pigmented ink composition recycled from a main ink supply reservoir, employing a printer with a fluid delivery system capable of measuring the ink electrical resistivity, and providing needed quantities of either vehicle replenisher fluid or fresh ink to maintain the desired recycled ink concentration. The electrical resistivity of the pigmented ink can be modified advantageously for stable ink recycling by the addition of the organic amine salt of an acid, and the pH stability of the ink can be simultaneously improved by the additional inclusion of the neutral form of the organic amine in similar molar proportions to the amine salt. The pigmented ink jet ink compositions provide for particularly stable and invariant fluid properties during periods of extended printer operation and ink recirculation.

Abstract: A continuous ink jet printer aqueous ink composition including pigment particles dispersed with a dispersant or self dispersing pigment particles without the need for a dispersant, and a polymer additive distinct from any dispersant used to disperse the pigment particles, wherein the polymer additive comprises a water soluble block copolymer having one or more poly(ethylene oxide) block segments wherein the polymer additive is present in an amount effective to stabilize the ink composition against shear induced agglomeration caused by pumping the ink composition through a continuous ink jet printing fluid system.

Abstract: A continuous ink jet printer aqueous ink composition including pigment particles dispersed with a dispersant or self dispersing pigment particles without the need for a dispersant, and a polymer additive distinct from any dispersant used to disperse the pigment particles, wherein the polymer additive comprises a styrene-acrylic copolymer that does not substantially displace any dispersant used to disperse the pigment, present in an amount effective to stabilize the ink composition against shear induced agglomeration caused by pumping the ink composition through a continuous ink jet printing fluid system.

Abstract: The invention relates to continuous ink jet printing of an aqueous pigmented ink composition recycled from a main ink supply reservoir, employing a printer with a fluid delivery system capable of measuring the ink electrical resistivity, and providing needed quantities of either vehicle replenisher fluid or fresh ink to maintain the desired recycled ink concentration. The electrical resistivity of the pigmented ink can be modified advantageously for stable ink recycling by the addition of the organic amine salt of an acid, and the pH stability of the ink can be simultaneously improved by the additional inclusion of the neutral form of the organic amine in similar molar proportions to the amine salt. The pigmented ink jet ink compositions provide for particularly stable and invariant fluid properties during periods of extended printer operation and ink recirculation.

Abstract: A pigment is synthesized in an aqueous medium and the pigment dispersion is purified by ultrafiltration or microfiltration. In particular, an aqueous pigment dispersion having a very small average particle size and a narrow particle size distribution may be prepared by the steps of (a) synthesizing a pigment in an aqueous medium and (b) removing an impurity such as a dissolved synthesis by-product or unreacted starting material through cross flow filtration using a membrane having an average pore diameter of from about 3 nanometers to about 3000 nanometers to produce a purified aqueous pigment dispersion.

Abstract: Salts of phenylazonaphthyl sulfonic acids useful as blue-red colorants for textile fabrics, cellulosic fibers and edible compositions are prepared by diazotizing aniline sulfonic acid and coupling the resulting diazo compound to a 1-hydroxynaphthalene mono- or disulfonic acid.

Abstract: Physiologically acceptable cation salts of (2-alkoxy-4-sulfonyl-5-alkylphenyl)azo-1-hydroxynaphthalene sulfonic acids useful as blue-red colorants for textile fabrics, cellulosic fibers and edible compositions are prepared by diazotizing 2-alkoxy-4-sulfonyl-5-alkylanilines and coupling the resulting diazo compounds to a 1-hydroxynaphthalene mono- or disulfonic acid.

Abstract: The disodium salt of 1-[(6-methoxy-4-sulfo-3-methylphenyl)azo]-2-naphthol-6-sulfonic acid (FD and C Red 40), the disodium salt of 1-[(4-sulfophenyl)azo]-2-naphthol-6-sulfonic acid (FD and C Yellow 6), the trisodium salt of 1-[1-(4-sulfonaphthyl)azo]-2-naphthol-3,6-disulfonic acid (FD and C Red 2), the disodium salt of 2-[1-(4-sulfonaphthyl)azo]-1-naphthol-4-sulfonic acid (Carmoisine) and the sodium salt of 2-(2-quinolyl)-1,3-indanedione-sulfonic acid (D and C Yellow 10) are prepared and purified in high yield and in a high state of purity by subjecting their aqueous reaction mixtures to ultrafiltration through a membrane of such structure and under such conditions that the impurities are separated from the reaction mixtures, and the products are concentrated in high purity concentrates from which the products can be isolated directly by evaporation of the solvent.