Water base pigment ink composition for inner lead type writing instrument

Inner lead type writing instruments having inner leads in which fiber bundles are bundled as ink containers and pen tips discharging inks contained in said inner leads, wherein said inks do not comprise white colored inorganic pigments or white colored resin particles as coloring materials, and the content of pigments is 0.5 to 7 wt %, the content of water-soluble resin is 2 to 10 wt % with respect to the total amount of the ink, and the viscosity is 3.5 to 10 mPa·s.

Inner lead type writing instruments having inner leads in which fiber bundles are bundled as ink containers and pen tips discharging inks contained in said inner leads, wherein said inks do not comprise white colored inorganic pigments or white colored resin particles as coloring materials, pigments other than said white colored inorganic pigments or white colored resin particles are one or more species selected from quinacridone red, DPP red, phthalocyanine blue, phthalocyanine green, azo yellow, and disazo yellow, said water-soluble resins are one or more species selected from acrylic acid resins, styrene-acryl acid resins, styrene-maleic acid resins, and the content of pigments other than said white colored inorganic pigments or white colored resin particles is 0.5 to 7 wt %, said water-soluble resin is 2 to 10 wt % with respect to the total amount of the ink, and the viscosity is 3.5 to 10 mPa·s.