Inkjet ink set and inkjet recording apparatus
An inkjet ink set includes an undercoat liquid and one or more inkjet inks. The undercoat liquid contains first binder resin particles, a first aqueous medium, and a first surfactant. The one or more inkjet inks each contain a second pigment, second binder resin particles, a second aqueous medium, and a second surfactant. At a temperature of 20° C., a density ρ1 of the undercoat liquid and a density ρ2 of an inkjet ink of the one or more inkjet inks that has the highest density among those of the one or more inkjet inks satisfy a relationship represented by formula (1): ρ1−ρ2>0.05 g/cm 3 . . . (1).
1 . An inkjet ink set comprising:
an undercoat liquid; and
one or more inkjet inks, wherein
the undercoat liquid contains first binder resin particles, a first aqueous medium, and a first surfactant,
the one or more inkjet inks each contain a second pigment, second binder resin particles, a second aqueous medium, and a second surfactant,
at a temperature of 20° C., a density ρ1 of the undercoat liquid and a density ρ2 of an inkjet ink of the one or more inkjet ink that has highest density among those of the one or more inkjet inks satisfy a relationship represented by formula (1) below:
ρ1
-
ρ2
>
0.05
g
/
cm
3
,
(
1
)
the density ρ1 of the undercoat liquid is at least 1.10 g/cm 3 and no greater than 1.20 g/cm 3 .
2 . The inkjet ink set according to claim 1 , wherein
the first binder resin particles have a volume median diameter of at least 100 nm and no greater than 250 nm.
3 . The inkjet ink set according to claim 1 , wherein
the density ρ2 of the inkjet ink of the inkjet inks that has the highest density among those of the one or more inkjet inks is at least 1.00 g/cm 3 and no greater than 1.09 g/cm 3 .
4 . The inkjet ink set according to claim 1 , wherein
the first binder resin particles include urethane resin particles.
5 . The inkjet ink set according to claim 1 , wherein
the inkjet ink set is used to print on a non-absorbent recording medium.
6 . The inkjet ink set according to claim 1 , wherein
the inkjet ink set is used in front printing.
7 . The inkjet ink set according to claim 1 , wherein
the first surfactant and the second surfactant both include a silicone surfactant.
8 . An inkjet recording apparatus comprising:
the inkjet ink set according to claim 1 ;
a conveyance section that conveys a recording medium;
an undercoat liquid ejection head that ejects the undercoat liquid onto the recording medium; and
one or more recording heads that are placed downstream of the undercoat liquid ejection head in terms of a conveyance direction of the recording medium and that eject the respective one or more inkjet inks onto at least a part of an area of the recording medium, the area being an area of the recording medium onto which the undercoat liquid has been ejected.
9 . The inkjet recording apparatus according to claim 8 , wherein
the undercoat liquid ejection head is a circulation type head.
10 . The inkjet recording apparatus according to claim 8 , further comprising
a drying device that is provided downstream of the one or more recording heads in terms of the conveyance direction of the recording medium and that dries the recording medium, wherein
the conveyance section preheats while conveying the recording medium.
11 . The inkjet ink set according to claim 1 , wherein
the undercoat liquid further contains a first pigment, a total percentage content of the first pigment and the first binder resin particles being at least 12.0% by mass and no greater than 20.0% by mass in the undercoat liquid,
the first aqueous medium contains water and a water-soluble organic solvent, a percentage content of the water being at least 70.0% by mass and no greater than 78.0% by mass in the undercoat liquid, and a percentage content of the water-soluble organic solvent being at least 5.0% by mass and no greater than 10.0% by mass in the undercoat liquid.
12 . An inkjet ink set comprising:
an undercoat liquid; and
one or more inkjet inks, wherein
the undercoat liquid contains first binder resin particles, a first aqueous medium, and a first surfactant,
the one or more inkjet inks each contain a second pigment, second binder resin particles, a second aqueous medium, and a second surfactant,
at a temperature of 20° C., a density ρ1 of the undercoat liquid and a density ρ2 of an inkjet ink of the one or more inkjet ink that has highest density among those of the one or more inkjet inks satisfy a relationship represented by formula (1) below:
ρ1−ρ2>0.05 g/cm 3 (1), and
the undercoat liquid further contains a first pigment, a total percentage content of the first pigment and the first binder resin particles being at least 12.0% by mass and no greater than 20.0% by mass in the undercoat liquid, of the undercoat liquid does not contain the first pigment, the first binder resin particles having a percentage content of at least 10.0% by mass and no greater than 18.0% by mass in the undercoat liquid.
13 . An inkjet ink set comprising:
an undercoat liquid; and
one or more inkjet inks, wherein
the undercoat liquid contains first binder resin particles, a first aqueous medium, and a first surfactant,
the one or more inkjet inks each contain a second pigment, second binder resin particles, a second aqueous medium, and a second surfactant,
at a temperature of 20° C., a density ρ1 of the undercoat liquid and a density ρ2 of an inkjet ink of the one or more inkjet ink that has highest density among those of the one or more inkjet inks satisfy a relationship represented by formula (1) below:
ρ1−ρ2>0.05 g/cm 3 (1),
the second binder resin particles include particles of at least one of urethane resin and polyester resin, and
the second binder resin particles have a breaking elongation of no greater than 60%.