Abstract: A non-aqueous pigment dispersion includes a quinacridone pigment, a polymeric dispersant, and a dispersion synergist in a non-aqueous dispersion medium wherein the dispersion synergist is a quinacridone derivative substituted on one of the two nitrogen atoms of the quinacridone basic chromophore structure by a group including at least one carboxyl group or a salt thereof. Also, a method for printing an ink-jet image with an ink including the non-aqueous pigment dispersion.

Abstract: A non-aqueous pigment dispersion includes a color pigment, a polymeric dispersant, and a dispersion synergist wherein the molecular weight of the anionic part of the dispersion synergist containing at least one carboxylate anion is smaller than 98% of the molecular weight of the color pigment and that the anionic part of the dispersion synergist has a similarity coefficient SIM of at least 0.5 with the similarity coefficient defined by: SIM = t · C S + P - C wherein, S represents the number of atoms in the anionic part of the dispersion synergist; P represents the number of atoms in the color pigment; C represents the largest number of atoms in common between the anionic part of the dispersion synergist and the color pigment as one continuous structure; and t is an integer representing the number of times that the largest number of atoms in common C fits into the organic color pigment, without using atoms of the color pigment twice.

Abstract: A non-aqueous pigment dispersion includes a color pigment, a polymeric dispersant, and a dispersion synergist in a dispersion medium wherein the dispersion synergist is represented by Formula (I): wherein AR1 and AR2 represent a substituted or unsubstituted aromatic group, and R represents a substituted or unsubstituted aliphatic group, with the proviso that one of R, AR1, and AR2 contains at least one carboxylate anion and that the molecular weight of the anionic part of the dispersion synergist is smaller than 98% of the molecular weight of the color pigment. Also, methods of preparing the non-aqueous pigment dispersions.

Abstract: A non-aqueous pigment dispersion includes a color pigment, a polymeric dispersant, and a dispersion synergist in a dispersion medium wherein the dispersion synergist is represented by Formula (I): wherein AR1 and AR2 represent a substituted or unsubstituted aromatic groups, and R represents a substituted or unsubstituted aliphatic group, with the proviso that one of R, AR1, and AR2 contains at least one carboxylate anion and that the molecular weight of the anionic part of the dispersion synergist is smaller than 98% of the molecular weight of the color pigment. Also, methods of preparing the non-aqueous pigment dispersions are also.

Abstract: A non-aqueous pigment dispersion includes a color pigment, a polymeric dispersant, and a dispersion synergist wherein the molecular weight of the anionic part of the dispersion synergist containing at least one carboxylate anion is smaller than 98% of the molecular weight of the color pigment and that the anionic part of the dispersion synergist has a similarity coefficient SIM of at least 0.5 with the similarity coefficient defined by: SIM = t · C S + P - C wherein, S represents the number of atoms in the anionic part of the dispersion synergist; P represents the number of atoms in the color pigment; C represents the largest number of atoms in common between the anionic part of the dispersion synergist and the color pigment as one continuous structure; and t is an integer representing the number of times that the largest number of atoms in common C fits into the organic color pigment, without using atoms of the color pigment twice.

Abstract: A non-aqueous pigment dispersion includes a quinacridone pigment, a polymeric dispersant, and a dispersion synergist in a non-aqueous dispersion medium wherein the dispersion synergist is a quinacridone derivative substituted on one of the two nitrogen atoms of the quinacridone basic chromophore structure by a group including at least one carboxyl group or a salt thereof. Also, a method for printing an ink-jet image with an ink including the non-aqueous pigment dispersion.