Ink-jet ink set, ink-jet recording method, and ink-jet recording apparatus
The present invention provides an ink-jet ink set including an ink-jet ink containing a colorant and a surfactant, and a treatment liquid, wherein an ink droplet formed by bringing the ink-jet ink into contact with the treatment liquid has a ratio (H/R) of height (H) to contact-area diameter (R) of from 0.15 to 0.30, the ratio (H/R) is detected at a point 100 milliseconds (ms) after ejecting the ink droplet onto a plain paper. The present invention also provides an ink-jet recording method and ink-jet recording apparatus using the ink-jet ink set.
1. An ink-jet ink set comprising: an ink-jet ink containing a colorant and a surfactant; and a treatment liquid, wherein an ink droplet formed by bringing the ink-jet ink into contact with the treatment liquid has a ratio (H/R) of height (H) to contact-area diameter (R) of from 0.15 to 0.30, said ratio (H/R) is detected, when the ink is in liquid form, at a point 100 milliseconds (ms) after ejecting the ink droplet onto a plain paper.
2. An ink-jet ink set according to claim 1 , wherein the surfactant comprises a branched-chain surfactant and a straight-chain surfactant.
3. An ink-jet ink set according to claim 2 , wherein the straight chain surfactant is an anionic surfactant.
4. An ink-jet ink set according to claim 3 , wherein the anionic straight-chain surfactant is an alkylaromatic surfactant having an alkyl group having 3 to 6 carbon atoms.
5. An ink-jet ink set according to claim 4 , wherein the alkylaromatic surfactant having an alkyl group having 3 to 6 carbon atoms is an alkylbenzenesulfate or an alkylnaphthalenesulfate.
6. An ink-jet ink set according to claim 2 , wherein the straight-chain surfactant is a nonionic surfactant.
7. An ink-jet ink set according to claim 6 , wherein the nonionic straight-chain surfactant is a polyoxyethylene straight-chain alkylether or a polyoxyethylene straight-chain alkylphenyl ether.
8. An ink-jet ink set according to claim 2 , wherein the branched-chain surfactant is a nonionic branched-chain surfactant.
9. An ink-jet ink set according to claim 8 , wherein the nonionic branched-chain surfactant is an acetylene glycol derivative or a polyoxyethylene branched-alkylether.
10. An ink-jet ink set according to claim 2 , wherein the straight-chain surfactant is an alkylaromatic surfactant having an alkyl group having 3 to 6 carbon atoms, and the branched-chain surfactant is a nonionic branched-chain surfactant.
11. An ink-jet ink set according to claim 2 , wherein the straight-chain surfactant is selected from polyoxyethylene straight-chain alkylethers, polyoxyethylene straight-chain alkylphenylethers, N-straight-chain alkyl-substituted pyridinium salts, alkylaromatic surfactants, and the branched-chain surfactant is selected from acetylene glycol derivatives, polyoxyethylene branched-alkylethers, dialkylsulfosuccinates, quatemary ammonium salts, N-branched alkyl-substituted pyridinium salts, betaine surfactants.
12. An ink-jet ink set according to claim 2 , wherein the straight-chain surfactant is selected from an alkylbenzenesulfate and an alkylnaphthalenesulfate, each having an alkyl chain of 3 to 6 carbon, and the branched-chain surfactant is selected from acetylene glycol derivatives and polyoxyethylene branched-alkylethers.
13. An ink-jet ink set according to claim 2 , wherein the ink-jet ink has the straight-chain surfactant in an amount of from 0.05 to 2.5% by mass to a total solids content of the ink-jet ink, and the ink-jet ink has the branched-chain surfactant in an amount of from 0.01 to 2.0% by mass to a total solids content of the ink-jet ink.
14. An ink-jet ink set according to claim 2 , wherein the ink-jet ink has the straight-chain surfactant in an amount of from 0.1 to 1.5% by mass to a total solids content of the ink-jet ink, and the ink-jet ink has the branched-chain surfactant in an amount of from 0.01 to 1.0% by mass to a total solids content of the ink-jet ink.
15. An ink-jet ink set according to claim 2 , wherein the ink-jet ink has a content ratio of the straight-chain surfactant to the branched-chain surfactant of from 1.2:1 to 20:1.
16. An ink-jet ink set according to claim 2 , wherein the ink-jet ink has a content ratio of the straight-chain surfactant to the branched-chain surfactant of from 1.5:1 to 7:1.
17. An ink-jet ink set according to claim 1 , wherein the ink-jet ink has a surface tension of from 18 to 30 mN/m, and has a viscosity of from 1.8 to 4.5 mPa·s.
18. An ink-jet ink set according to claim 1 , wherein the treatment liquid has the surface tension of from 20 to 50 mN/m, and has the viscosity of from 1.5 to 3.5 mPa·s.
19. An ink-jet ink set according to claim 1 , wherein the ink-jet ink and the treatment liquid have an absolute value of the difference in pH of 3.0 or more.
20. An ink-jet recording method using an ink-jet ink containing a colorant and a surfactant, and a treatment liquid, comprising forming images by bringing the ink-jet ink into contact with the treatment liquid on to a recording medium, wherein an ink droplet formed by bringing the ink-jet ink into contact with the treatment liquid has a ratio (H/R) of height (H) to contact-area diameter (R) of from 0.15 to 0.30, said ratio (H/R) is detected, when the ink is in liquid form, at a point 100 milliseconds (ms) after ejecting the ink droplet onto a plain paper.
21. An ink-jet recording method according to claim 20 , wherein the surfactant comprises an alkylaromatic surfactant having an alkyl group having 3 to 6 carbon atoms and a nonionic branched surfactant.
22. An ink-jet recording method according to claim 20 , wherein the ink-jet ink and the treatment liquid have a total ejected amount per unit area of from 0.2 to 1.5 mg/cm 2 in a printing mode of 400 to 1200 dpi.
23. An ink-jet recording method according to claim 20 , wherein the ink-jet ink and the treatment liquid have a total ejected amount per unit area of from 0.3 to 1.0 mg/cm 2 in a printing mode of 400 to 1200 dpi.
24. An ink-jet recording method according to claim 20 , wherein the treatment liquid has an ejected amount of from 5% to 30% of the ejected amount of the ink-jet ink.
25. An ink-jet recording method according to claim 20 , wherein the treatment liquid has the ejected amount of from 5% to 15% of the ejected amount of the ink-jet ink.
26. An ink-jet recording apparatus using an ink-jet ink set containing an ink-jet ink and a treatment liquid, wherein an ink droplet formed by bringing the ink-jet ink into contact with the treatment liquid has a ratio (H/R) of height (H) to contact-area diameter (R) of from 0.15 to 0.30, said ratio (H/R) is detected, when the ink is in liquid form, at a point 100 milliseconds (ms) after ejecting the ink droplet onto a plain paper.