Ink-jet recording ink set and ink-jet recording method
An ink-jet recording ink set, containing at least one recording liquid containing a colorant and a polymerizable compound and an ink spread suppressing liquid containing at least one surfactant and substantially no colorant, wherein all of the following conditions (A), (B) and (C) are satisfied, and an ink-jet recording method using the same: (A) the surface tension of the ink spread suppressing liquid is smaller than that of at least one recording liquid contained in the ink-jet recording ink set; (B) at least one of the surfactants contained in the ink spread suppressing liquid satisfies the following relationship: γ s (0)−γ s (saturated)>1 mN/m; and (C) the surface tension of the ink spread suppressing liquid satisfies the following relationship: γ s <(γ s (0)+γ s (saturated) max )/2.
1. An ink-jet recording ink set, comprising at least one recording liquid containing a colorant and a polymerizable compound and an ink spread suppressing liquid containing at least one surfactant and substantially no colorant, wherein all of the following conditions (A), (B) and (C) are satisfied:
(A) the surface tension of the ink spread suppressing liquid is smaller than that of at least one recording liquid contained in the ink-jet recording ink set;
(B) at least one of the surfactants contained in the ink spread suppressing liquid satisfies the following relationship:
γ s (0)−γ s (saturated)>1 mN/m; and
(C) the surface tension of the ink spread suppressing liquid satisfies the following relationship:
γ s <(γ s (0)+γ s (saturated) max )/2,
wherein, γ s represents the surface tension of the ink spread suppressing liquid; γ s (0) represents the surface tension of a liquid obtained by eliminating all surfactants from the ink spread suppressing liquid; γ s (saturated) represents the saturated surface tension of the liquid obtained by eliminating all surfactants from the ink spread suppressing liquid when one of the surfactants contained in the ink spread suppressing liquid is added to the liquid obtained by eliminating all surfactants from the ink spread suppressing liquid until the surface tension thereof becomes saturated; and γ s (saturated) max represents the maximum value of the γ s (saturated) values of all surfactants satisfying the condition (B) contained in the ink spread suppressing liquid.
2. The ink-jet recording ink set of claim 1 , wherein the surface tension of the ink spread suppressing liquid is lower than that of the recording liquid containing a colorant higher in visual sensitivity among the recording liquid contained in the ink-jet recording ink set.
3. The ink-jet recording ink set of claim 1 , wherein the surface tension of the ink spread suppressing liquid is lower than that of any recording liquid contained in the ink-jet recording ink set.
4. The ink-jet recording ink set of claim 1 , wherein the concentration Ms, in the ink spread suppressing liquid, of at least one surfactant among the surfactants contained in the ink spread suppressing liquid is larger than the concentration Mk, in the recording liquid, of said surfactant.
5. The ink-jet recording ink set of claim 1 , wherein at least one of the recording liquid and the ink spread suppressing liquid contains a polymerization initiator.
6. The ink-jet recording ink set of claim 1 , wherein the polymerizable compound is a radical-polymerization compound.
7. The ink-jet recording ink set of claim 1 , wherein the polymerizable compound is insoluble in water.
8. An ink-jet recording method using an ink-jet recording ink set comprising at least one recording liquid containing a colorant and a polymerizable compound and an ink spread suppressing liquid containing at least one surfactant and substantially no colorant, the method comprising
forming an image on a recording medium by applying the recording liquid and the ink spread suppressing liquid; and
hardening the formed image by applying energy thereto,
wherein all of the following conditions (A), (B) and (C) are satisfied:
(A) the surface tension of the ink spread suppressing liquid is smaller than that of at least one recording liquid contained in the ink-jet recording ink set;
(B) at least one of the surfactants contained in the ink spread suppressing liquid satisfies the following relationship:
γ s (0)−γ s (saturated)>1 mN/m; and
(C) the surface tension of the ink spread suppressing liquid satisfies the following relationship:
γ s <(γ s (0)+γ s (saturated) max )/2,
wherein, γ s represents the surface tension of the ink spread suppressing liquid; γ s (0) represents the surface tension of a liquid obtained by eliminating all surfactants from the ink spread suppressing liquid; γ s (saturated) represents the saturated surface tension of the liquid obtained by eliminating all surfactants from the ink spread suppressing liquid when one of the surfactants contained in the ink spread suppressing liquid is added to the liquid obtained by eliminating all surfactants from the ink spread suppressing liquid until the surface tension thereof becomes saturated; and γ s (saturated) max represents the maximum value of the γ s (saturated) values of all surfactants satisfying the condition (B) contained in the ink spread suppressing liquid.
9. The ink-jet recording method of claim 8 , wherein the ink spread suppressing liquid is applied on an area corresponding to the image to be formed on the recording medium with droplets of the recording liquid or an area wider than the area corresponding to the image, before application of the droplets of the recording liquid.
10. The ink-jet recording method of claim 8 , wherein the forming of the image on the recording medium by applying the recording liquid and the ink spread suppressing liquid is a single-pass process.
11. The ink-jet recording method of claim 8 , wherein the energy is applied by photoirradiation or heating.
12. The ink-jet recording method of claim 8 , wherein the energy is applied only once after the forming of the image.
13. The ink-jet recording method of claim 8 , wherein the surface tension of the ink spread suppressing liquid is lower than that of the recording liquid containing a colorant higher in visual sensitivity among the recording liquid contained in the ink-jet recording ink set.
14. The ink-jet recording method of claim 8 , wherein the surface tension of the ink spread suppressing liquid is lower than that of any recording liquid contained in the ink-jet recording ink set.
15. The ink-jet recording method of claim 8 , wherein the concentration Ms, in the ink spread suppressing liquid, of at least one surfactant among the surfactants contained in the ink spread suppressing liquid is larger than the concentration Mk, in the recording liquid, of said surfactant.
16. The ink-jet recording method of claim 8 , wherein at least one of the recording liquid and the ink spread suppressing liquid contains a polymerization initiator.
17. The ink-jet recording method of claim 8 , wherein the polymerizable compound is a radical-polymerization compound.
18. The ink-jet recording method of claim 8 , wherein the polymerizable compound is insoluble in water.