Pretreatment ink and ink set containing same
A pretreatment ink that suppresses white spots, suppresses the occurrence of overflow defects from water-based ink, and can produce recorded matter having high image reproducibility. This pretreatment ink, which is coated in advance onto a base material before a water-based ink is coated onto the base material, contains at least a reaction agent, water, and an organic solvent. The organic solvent includes a water-soluble solvent A selected from the group consisting of alkanediols and monools.
1 . An ink set comprising a pretreatment ink to be applied to a substrate in advance of application of a water-based ink to the substrate, and the water-based ink to be applied on the pretreatment ink:
the pretreatment ink comprising at least:
a reactant; water; an organic solvent; and a resin, wherein at least a portion of the resin is contained as a resin emulsion,
the organic solvent comprising a water-soluble solvent A selected from the group consisting of an alkanediol and a monool;
the water-based ink comprising a colorant; and
the static surface tensions of the respective inks comprised in the ink set satisfy the following relation:
static surface tension Sp of the pretreatment ink<static surface tension Sc of the water-based ink.
2 . The ink set according to claim 1 , wherein the water-soluble solvent A is selected from the group consisting of a 1,2-alkanediol and a monool.
3 . The ink set according to claim 1 , wherein the content of the water-soluble solvent A is in a range of 5 mass % or more and 50 mass % or less based on the total mass of the pretreatment ink.
4 . The ink set according to claim 1 , wherein the reactant comprises a cationic group-containing compound.
5 . The ink set according to claim 4 , wherein the cationic group-containing compound comprises a cationic resin.
6 . The ink set according to claim 1 ,
wherein the surfactant comprises a silicone surfactant and/or an acetylene glycol surfactant.
7 . The ink set according to claim 1 , wherein each of the inks comprised in the ink set is to be jetted by an inkjet method.
8 . The ink set according to claim 1 , further comprising an overcoat ink for forming an overcoat layer on a surface of a recorded matter.
9 . The ink set according to claim 8 , wherein the pretreatment ink, the water-based ink, and the overcoat ink have static surface tensions satisfying the following relation:
the static surface tension S O of the overcoat ink≤the static surface tension S P of the pretreatment ink<the static surface tension S C of the water-based ink.
10 . An inkjet recording method using the ink set according to claim 1 , the inkjet recording method comprising:
jetting each of the inks comprised in the ink set onto a substrate.
11 . The inkjet recording method according to claim 10 , wherein each of the inks is jetted onto the substrate by an inkjet method, such that drying mechanism is not placed between at least one adjacent pairs of ejection parts jetting each of the inks comprised in the ink set.
12 . The inkjet recording method according to claim 10 , wherein each of the inks comprised in the ink set is dried after the ink jetting.
13 . A method according to claim 1 , the method comprising:
jetting each of the inks comprised in the ink set onto a substrate.
14 . A device for jetting the inks comprised in the ink set according to claim 1 .
15 . The device according to claim 14 , wherein the device comprises ejection units for respectively jetting the inks of the ink set, and the device has no drying mechanism between at least one of adjacent pairs of the ejection units.
16 . The device according to claim 14 , further comprising drying mechanisms for drying each of the inks comprised in the ink set after ink jetting.
17 . The ink set according to claim 2 , wherein the content of the water-soluble solvent A is in a range of 5 mass % or more and 50 mass % or less based on the total mass of the pretreatment ink.
18 . The ink set according to claim 2 , wherein the reactant comprises a cationic group-containing compound.