Patent ID: 8757786
Filing Date: 2014-06-24
Classification: B41J,B41M,C09D

Abstract:
1. An ink set comprising: a yellow ink composition containing a resin-coated yellow pigment in which a yellow pigment is coated with a crosslinked water-soluble resin, a water-soluble polymerizable compound and water; a magenta ink composition containing a resin-coated magenta pigment in which a magenta pigment is coated with a crosslinked water-soluble resin, a water-soluble polymerizable compound and water; a cyan ink composition containing a resin-coated cyan pigment in which a cyan pigment is coated with a crosslinked water-soluble resin, a water-soluble polymerizable compound and water; and a treatment liquid containing an aggregating agent for aggregating components in the ink compositions, wherein the yellow pigment is C.I. Pigment Yellow 74, the magenta pigment is at least one selected from the group consisting of C.I. Pigment Red 122, C.I. Pigment Red 202, C.I. Pigment Red 209 and C.I. Pigment Violet 19, and the cyan pigment is at least one selected from the group consisting of C.I. Pigment Blue 15:3 and C.I. Pigment Blue 15:4, wherein the resin-coated yellow pigment has a volume average particle diameter of from 50 nm to 150 nm, the resin-coated magenta pigment has a volume average particle diameter of from 50 nm to 150 nm, and the resin-coated cyan pigment has a volume average particle diameter of from 50 nm to 150 nm, wherein a content of resin particles in the yellow ink composition is 3% by mass or less based on the total amount of the yellow ink composition, a content of resin particles in the magenta ink composition is 3% by mass or less based on the total amount of the magenta ink composition, and a content of resin particles in the cyan ink composition is 3% by mass or less based on the total amount of the cyan ink composition, and wherein, when a red, green or blue image is formed by superposing any two ink compositions selected from the group consisting of the yellow ink composition, the magenta ink composition and the cyan ink composition, the yellow ink composition, the magenta ink composition or the cyan ink composition jetted first among the two ink compositions satisfies one of the following requirements (1) to (3): (1) when the ink composition jetted first among the two ink compositions is the magenta ink composition, the magenta ink composition has a content of the magenta pigment of from 4.2 to 6.0% by mass based on the total amount of the magenta ink composition, and a mass ratio of the crosslinked water-soluble resin to the magenta pigment (mass of crosslinked water-soluble resin/mass of magenta pigment) is 0.25 or more; (2) when the ink composition jetted first among the two ink compositions is the cyan ink composition, the cyan ink composition has a content of the cyan pigment of from 2.0 to 4.0% by mass based on the total amount of the cyan ink composition, and a mass ratio of the crosslinked water-soluble resin to the cyan pigment (mass of crosslinked water-soluble resin/mass of cyan pigment) is 0.40 or more; or (3) when the ink composition jetted first among the two ink compositions is the yellow ink composition, the yellow ink composition has a content of the yellow pigment of from 3.0 to 6.0% by mass based on the total amount of the yellow ink composition, and a mass ratio of the crosslinked water-soluble resin to the yellow pigment (mass of crosslinked water-soluble resin/mass of yellow pigment) is 0.40 or more.