A process for the production of a quinacridone pigment composition is provided. For use in environmentally friendly inks, the pigment composition offers high chroma, high color strength, and high dispersion stability. Also provided is a water- or alcohol-based environmentally friendly ink that contains a quinacridone pigment composition obtained through this process. According to the inventors' research, adding a quinacridone derivative to a quinacridone solid solution in two different steps in a process, during and after treatment for the control of crystals, gives the resulting pigment composition the color characteristics of high color strength and high chroma, as well as high dispersion stability. The present invention is based on these findings.

The present disclosure is drawn to aqueous pigment co-dispersions. The co-dispersions include self-dispersed pigment with a chemically modified surface; released surface moieties from the self-dispersing pigment; pigment powder having the released surface moieties associated with pigment powder surfaces; polymeric dispersant; and water.

The present disclosure is drawn to aqueous pigment co-dispersions. The co-dispersions include self-dispersed pigment with a chemically modified surface; released surface moieties from the self-dispersing pigment; pigment powder having the released surface moieties associated with pigment powder surfaces; polymeric dispersant; and water.

Provided are a quinacridone pigment having a low content of a primary aromatic amine, a method for producing the same, and also a gravure and flexo ink, a colorant for plastic, a paint, a lithographic ink, a toner, or an ink-jet ink using the pigment. The quinacridone pigment having a low primary aromatic amine content is provided by washing a quinacridone pigment with at least one solvent selected from water and an organic solvent, or by adding an oxidizing agent to a pigment slurry including a quinacridone pigment and at least one solvent selected from water and an organic solvent to oxidatively decompose the aromatic amine.

Provided are a quinacridone pigment having a low content of a primary aromatic amine, a method for producing the same, and also a gravure and flexo ink, a colorant for plastic, a paint, a lithographic ink, a toner, or an ink-jet ink using the pigment. The quinacridone pigment having a low primary aromatic amine content is provided by washing a quinacridone pigment with at least one solvent selected from water and an organic solvent, or by adding an oxidizing agent to a pigment slurry including a quinacridone pigment and at least one solvent selected from water and an organic solvent to oxidatively decompose the aromatic amine.

A process for the production of a quinacridone pigment composition is provided. For use in environmentally friendly inks, the pigment composition offers high chroma, high color strength, and high dispersion stability. Also provided is a water- or alcohol-based environmentally friendly ink that contains a quinacridone pigment composition obtained through this process. According to the inventors' research, adding a quinacridone derivative to a quinacridone solid solution in two different steps in a process, during and after treatment for the control of crystals, gives the resulting pigment composition the color characteristics of high color strength and high chroma, as well as high dispersion stability. The present invention is based on these findings.

A process for the production of a quinacridone pigment composition is provided. For use in environmentally friendly inks, the pigment composition offers high chroma, high color strength, and high dispersion stability. Also provided is a water- or alcohol-based environmentally friendly ink that contains a quinacridone pigment composition obtained through this process. According to the inventors' research, adding a quinacridone derivative to a quinacridone solid solution in two different steps in a process, during and after treatment for the control of crystals, gives the resulting pigment composition the color characteristics of high color strength and high chroma, as well as high dispersion stability. The present invention is based on these findings.

An object of the present invention is to provide an innovative quinacridone pigment that can exhibit even better viscosity stability than conventional pigments and also maintain high saturation in aqueous IJ ink uses. The quinacridone pigment of the present invention has a specific surface area ratio between water vapor and nitrogen of 0.270 or more and less than 0.430. The pigment dispersion of the present invention contains the quinacridone pigment and a solvent. The aqueous inkjet ink of the present invention contains the pigment dispersion.

An object of the present invention is to provide an innovative quinacridone pigment that can exhibit even better viscosity stability than conventional pigments and also maintain high saturation in aqueous IJ ink uses. The quinacridone pigment of the present invention has a specific surface area ratio between water vapor and nitrogen of 0.270 or more and less than 0.430. The pigment dispersion of the present invention contains the quinacridone pigment and a solvent. The aqueous inkjet ink of the present invention contains the pigment dispersion.

There is provided a photoelectric conversion film including a quinacridone derivative represented by the following General formula and a subphthalocyanine derivative represented by the following General formula.