INK SET INCLUDING A PRE-TREATMENT FIXING FLUID AND A FIXABLE, UV CURABLE INK

A fixable, UV curable ink includes an aqueous ink vehicle including water and a co-solvent, a pigment, 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 fixable, UV curable ink. A base may be included in an amount sufficient to adjust a pH of the UV curable ink so that it ranges from 7.5 to 9.5. An additive may be included and selected from the group consisting of a biocide, a non-ionic surfactant, an anti-kogation agent, a buffer, and combinations thereof.