Quinacridone solid solution pigment, pigment dispersion, method of producing quinacridone solid solution pigment, method of producing pigment dispersion, and ink

A pigment dispersion comprising:

• a dispersion medium;
• and
• a pigment dispersed in the dispersion medium,
• wherein the pigment is a quinacridone solid solution pigment including at least two kinds of quinacridone-based pigments including unsubstituted quinacridone and 2,9-dialkylquinacridone, and
• wherein when a diffraction peak intensity at a diffraction angle 2θ of 5.9°±0.2° and a diffraction peak intensity at a diffraction angle 2θ of 6.4°±0.2°, which are obtained by X-ray diffractometry, are represented by T1 and T2, respectively, T1 and T2 satisfy T2/(T1+T2)≤0.13.

A method of producing a pigment dispersion comprising:

• a kneading step of kneading a mixture containing at least two kinds of quinacridone-based pigments including unsubstituted quinacridone and 2,9-dialkylquinacridone, a water-soluble inorganic salt, and a water-soluble organic solvent with a kneading apparatus to provide a pigment-kneaded product containing a quinacridone solid solution pigment;
• and
• a dispersing step of dispersing the quinacridone solid solution pigment in a dispersion medium after removing the water-soluble inorganic salt and the water-soluble organic solvent from the pigment-kneaded product,
• wherein the kneading step includes kneading the mixture with a kneading energy of 15 kWh/kg or more per unit mass (kg) of the quinacridone-based pigments.