Ink set and method for recording printed matter
An ink set including an inkjet ink, and a treatment liquid used in combination with the inkjet ink, wherein the inkjet ink includes a pigment, a water-soluble organic solvent, a surfactant and water, the treatment liquid includes a coagulant, an organic solvent and water, the coagulant includes calcium nitrate in an amount of 21.5 to 41.7% by mass relative to the total mass of the treatment liquid, an amount of organic solvent having a boiling point at one atmosphere of 240° C. or higher in the treatment liquid is not more than 8% by mass, a pH of the treatment liquid is within a range from 3.5 to 10.5, and a viscosity of the treatment liquid at 25° C. is within a range from 5.5 to 18.5 mPa·s.
1. An ink set comprising an inkjet ink, and a treatment liquid used in combination with the inkjet ink, wherein
the inkjet ink comprises a pigment, a water-soluble organic solvent, a surfactant and water,
the treatment liquid comprises a coagulant, an organic solvent, a binder resin, and water,
the coagulant comprises calcium nitrate in an amount of 24.3 to 34.7% by mass relative to the total mass of the treatment liquid, and the amount of calcium nitrate is calculated in terms of anhydrous calcium nitrate,
an amount of organic solvent having a boiling point at one atmosphere of 240° C. or higher in the treatment liquid is not more than 8% by mass,
the binder resin contains at least one resin selected from the group consisting of polyvinyl alcohols having a degree of saponification of at least 95%, (meth)acrylic resins having an acid value of not more than 100, and styrene-(meth)acrylic resins having an acid value of not more than 100, and
a pH of the treatment liquid is within a range from 3.5 to 10.5, and a viscosity of the treatment liquid at 25° C. is within a range from 5.5 to 18.5 mPa s.
2. The ink set according to claim 1 , which is used for recording to a recording medium that exhibits an amount of absorption of pure water in a contact time of 100 msec, measured using a dynamic scanning absorption meter, of 5 to 15 g/m 2 .
3. The ink set according to claim 1 , wherein the treatment liquid also comprises a basic pH adjuster.
4. The ink set according to Clam 1 , wherein
the inkjet ink also comprises a resin, and
an amount of the resin, relative to a solid fraction of the inkjet ink, is within a range from 30% by mass to 90% by mass.
5. The ink set according to claim 4 , wherein an acid value of the resin is within a range from 10 to 65 mgKOH/g.
6. The ink set according to claim 1 , wherein the inkjet ink also comprises a wax.
7. The ink set according to claim 1 , wherein an amount of organic solvent having a boiling point at one atmosphere of 240° C. or higher in the inkjet ink is not more than 8% by mass.
8. A method for producing printed matter using the ink set according to claim 1 , the method comprising:
applying the treatment liquid to a recording medium, and
applying the inkjet ink in a state where a drying rate of the treatment liquid on the recording medium is not more than 10% in terms of mass.
9. Printed matter obtained by printing the ink set according to claim 1 onto a recording medium.
10. The ink set according to claim 1 , wherein the treatment liquid further comprises a nonionic water-soluble resin.