Inkjet ink and inkjet recording apparatus
An inkjet ink contains a quinacridone pigment, a resin, and an aqueous medium. A ratio of a mass of the resin to a mass of the quinacridone pigment is no greater than 0.50. The resin has an acid value of at least 60 mgKOH/g and no greater than 120 mgKOH/g. A supernatant has a phosphorus concentration of no greater than 2.0 ppm. The supernatant is obtained by centrifugation of the inkjet ink at 1,050,000 G for 3 hours.
1 . An inkjet ink comprising:
a quinacridone pigment;
a resin; and
an aqueous medium, wherein
a ratio of a mass of the resin to a mass of the quinacridone pigment is no greater than 0.50,
the resin has an acid value of at least 60 mgKOH/g and no greater than 120 mgKOH/g,
a supernatant has a phosphorus concentration of no greater than 2.0 ppm, the supernatant being obtained by centrifugation of the inkjet ink at 1,050,000 G for 3 hours, and
the resin includes at least one repeating unit derived from (meth)acrylic acid, at least one repeating unit derived from alkyl (meth)acrylate, and a repeating unit derived from styrene selected from styrene, a-methylstyrene, and vinyltoluene.
2 . The inkjet ink according to claim 1 , wherein
the phosphorus concentration is at least 1.0 ppm and no greater than 2.0 ppm.
3 . The inkjet ink according to claim 1 , wherein
the ratio of the mass of the resin to the mass of the quinacridone pigment is at least 0.35 and no greater than 0.50.
4 . The inkjet ink according to claim 1 , wherein
the at least one repeating unit derived from (meth)acrylic acid has a percentage content to a mass of all repeating units included in the resin of at least 4.5% by mass and no greater than 10.0% by mass.
5 . The inkjet ink according to claim 1 , wherein
the phosphorous concentration is a concentration of a phosphorous atom included in at least one selected from the group consisting of polyphosphoric acid and a derivative thereof.
6 . The inkjet ink according to claim 1 , wherein
the resin consists of at least one repeating unit derived from (meth)acrylic acid, at least one repeating unit derived from alkyl (meth)acrylate, and a repeating unit derived from styrene selected from styrene, α-methylstyrene, and vinyltoluene.