A process for preparing a dispersion comprising the stages: i) providing a dispersion comprising a particulate solid, a liquid medium and a dispersant having cross-linkable groups and a weight averaged molecular weight of from 1,000 to 70,000; and ii) cross-linking the dispersant in the presence of the particulate solid and the liquid medium thereby preparing a dispersion of an encapsulated particulate solid, wherein the cross-linking is performed such that 0.01 to 0.5 mmoles of cross-linkable groups in the dispersant are cross-linked per g of dispersant; said process also comprising at any stage: iii) adding a metal chelating agent to the dispersion; and after stage iii) the stage of: iv) removing at least some of the metal chelating agent from the dispersion.

A process for preparing a dispersion comprising the stages: i) providing a dispersion comprising a particulate solid, a liquid medium and a dispersant having cross-linkable groups and a weight averaged molecular weight of from 1,000 to 70,000; and ii) cross-linking the dispersant in the presence of the particulate solid and the liquid medium thereby preparing a dispersion of an encapsulated particulate solid, wherein the cross-linking is performed such that 0.01 to 0.5 mmoles of cross-linkable groups in the dispersant are cross-linked per g of dispersant; said process also comprising at any stage: iii) adding a metal chelating agent to the dispersion; and after stage iii) the stage of: iv) removing at least some of the metal chelating agent from the dispersion.

An ink set includes a pre-treatment fixing fluid including at least two metal salts and a fixable, ultraviolet (UV) curable ink. The UV curable ink includes an aqueous ink vehicle, a pigment dispersed in the aqueous ink vehicle, and a dispersant. A polyurethane polymer dispersion is suspended as droplets within the aqueous ink vehicle. The polyurethane polymer dispersion includes a polyurethane polymer selected from the group consisting of a polyether-based polyurethane, a polyester-based polyurethane, a polycarbonate-based polyurethane, and mixtures thereof. The polyurethane polymer has i) an acid number ranging from 0 mg/g to less than 20 mg/g and ii) a glass transition temperature of less than 0 C. A water soluble or water dispersible photoinitiator is present in the pre-treatment fixing fluid or in the fixable, UV curable ink.

An ink set includes a pre-treatment fixing fluid including at least two metal salts and a fixable, ultraviolet (UV) curable ink. The UV curable ink includes an aqueous ink vehicle, a pigment dispersed in the aqueous ink vehicle, and a dispersant. A polyurethane polymer dispersion is suspended as droplets within the aqueous ink vehicle. The polyurethane polymer dispersion includes a polyurethane polymer selected from the group consisting of a polyether-based polyurethane, a polyester-based polyurethane, a polycarbonate-based polyurethane, and mixtures thereof. The polyurethane polymer has i) an acid number ranging from 0 mg/g to less than 20 mg/g and ii) a glass transition temperature of less than 0 C. A water soluble or water dispersible photoinitiator is present in the pre-treatment fixing fluid or in the fixable, UV curable ink.

The present disclosure provides an encapsulated pigment dispersion and an inkjet ink comprising an ink vehicle and an encapsulated pigment dispersion thereof. In particular, the encapsulated pigment dispersion includes a pigment selected from TiO.sub.2 pigment, fluorescent pigment, phosphorescent pigment, and mixtures thereof. The present disclosure also provides a process for producing the aqueous pigment.

The present disclosure provides an encapsulated pigment dispersion and an inkjet ink comprising an ink vehicle and an encapsulated pigment dispersion thereof. In particular, the encapsulated pigment dispersion includes a pigment selected from TiO.sub.2 pigment, fluorescent pigment, phosphorescent pigment, and mixtures thereof. The present disclosure also provides a process for producing the aqueous pigment.

A three-dimensional (3D) printing system includes a fabrication bed, a build material to be introduced into the fabrication bed, an inkjet applicator, a coalescing agent to be selectively introduced by the inkjet applicator onto the build material in the fabrication bed, and a radiation source to expose the coalescing agent and the build material in the fabrication bed to electromagnetic radiation. The coalescing agent includes a co-solvent having a boiling point of less than 300 C, a surfactant having a hydrophilic lipophilic balance (HLB) value that is less than 10, a carbon black pigment, a polymeric dispersant, and a balance of water.

A three-dimensional (3D) printing system includes a fabrication bed, a build material to be introduced into the fabrication bed, an inkjet applicator, a coalescing agent to be selectively introduced by the inkjet applicator onto the build material in the fabrication bed, and a radiation source to expose the coalescing agent and the build material in the fabrication bed to electromagnetic radiation. The coalescing agent includes a co-solvent having a boiling point of less than 300 C, a surfactant having a hydrophilic lipophilic balance (HLB) value that is less than 10, a carbon black pigment, a polymeric dispersant, and a balance of water.

Provided in one example herein is an aqueous ink composition, comprising: pigment particles comprising at least one metal oxide; an aqueous medium; and a cationic double-chain surfactant comprising a quaternary ammonium salt. Methods of making and using the ink composition are also provided.

A hydrophilic pigment dispersant for an inkjet ink includes water and a hydrophilic polyurethane having a weight average molecular weight from 3,000 to 15,000, and an acid number ranging from 50 to 100. The polyurethane is formed from 25 wt % to 70 wt % of a non-aromatic polyisocyanate; 0 wt % to 60 wt % of a polyol having a weight average molecular weight from 500 to 5,000; 0 wt % to 30 wt % of an aromatic diol having a weight average molecular weight ranging from 100 to 1000; 5 wt % to 25 wt % of an acid monomer having a hydroxyl functional group, an amino functional group, or both hydroxyl and amino functional groups; and 0 wt % to 5 wt % of a polyethyleneoxide compound having a hydroxyl functional group, an amino functional group, or both hydroxyl and amino functional groups; wherein at least one of the polyol or the aromatic diol is present.