Ink jet recording apparatus
An ink jet recording apparatus includes a liquid-ejecting head including a pressure-generating chamber filled with a photocurable ink composition containing a polymerizable functional group-containing compound and water, a nozzle communicating with the pressure-generating chamber and ejecting a droplet of the photocurable ink composition, and a pressure-generating member causing a pressure change in the pressure-generating chamber; and an ejection pulse-generating unit generating an ejection pulse for driving the pressure-generating member.
1. An ink jet recording apparatus comprising:
a liquid-ejecting head including a pressure-generating chamber filled with a photocurable ink composition containing a polymerizable functional group-containing compound and water, a nozzle communicating with the pressure-generating chamber and ejecting a droplet of the photocurable ink composition, and a pressure-generating member causing a pressure change in the pressure-generating chamber; and
an ejection pulse-generating unit generating an ejection pulse for driving the pressure-generating member, wherein
the ejection pulse includes:
a first voltage-changing factor expanding the volume of the pressure-generating chamber to pull a meniscus into the nozzle;
a second voltage-changing factor contracting the volume of the pressure-generating chamber to push the meniscus from the nozzle after the first voltage-changing factor;
a third voltage-changing factor causing a volume-expanding change for expanding the pressure-generating chamber after the second voltage-changing factor; and
a fourth voltage-changing factor causing a volume-contracting change for contracting the pressure-generating chamber after the third voltage-changing factor, and
the ink droplet is discharged from the nozzle by means of the ejection pulse.
2. The ink jet recording apparatus according to claim 1 , wherein the second voltage-changing factor and the third voltage-changing factor respectively give a voltage variation (ΔVhb) and a voltage variation (ΔVhc) satisfying Expression (A): ΔVhc/ΔVhb≧0.5.
3. An ink jet recording method using an ink jet recording apparatus according to claim 2 .
4. The ink jet recording apparatus according to claim 1 , wherein the polymerizable functional group-containing compound has a content of 10% by mass or more based on 100% by mass of the photocurable ink composition.
5. An ink jet recording method using an ink jet recording apparatus according to claim 4 .
6. The ink jet recording apparatus according to claim 1 , wherein the photocurable ink composition contains the polymerizable functional group-containing compound at least as an emulsion or as a polymerizable functional group-containing water-soluble compound.
7. An ink jet recording method using an ink jet recording apparatus according to claim 6 .
8. The ink jet recording apparatus according to claim 1 , wherein
the ejection pulse includes a third hold factor for holding the voltage of the third voltage-changing factor for a certain period of time between the third voltage-changing factor and the fourth voltage-changing factor; and
the third hold factor has a holding time of 1.5 μs or less.
9. An ink jet recording method using an ink jet recording apparatus according to claim 8 .
10. The ink jet recording apparatus according to claim 1 , wherein the first voltage-changing factor and the second voltage-changing factor respectively give a voltage variation (ΔVha) and a voltage variation (ΔVhb) satisfying Expression (B): ΔVhb/ΔVha≧0.7.
11. An ink jet recording method using an ink jet recording apparatus according to claim 10 .
12. The ink jet recording apparatus according to claim 1 , wherein the change in volume of the pressure-generating chamber by the third voltage-changing factor is smaller than the change in volume of the pressure-generating chamber by the first voltage-changing factor.
13. An ink jet recording method using an ink jet recording apparatus according to claim 12 .
14. The ink jet recording apparatus according to claim 1 , wherein
the ejection pulse includes a first hold factor for holding the voltage of the first voltage-changing factor for a certain period of time between the first voltage-changing factor and the second voltage-changing factor.
15. An ink jet recording method using an ink jet recording apparatus according to claim 14 .
16. The ink jet recording apparatus according to claim 1 , wherein the ink droplet has a mass of 3.0 ng or less.
17. The ink jet recording apparatus according to claim 1 , wherein the ink droplet is discharged at a discharge speed of 3.0 m/s or more.
18. The ink jet recording apparatus according to claim 1 , wherein the ejection pulse has a frequency of 10 kHz or more.
19. The ink jet recording apparatus according to claim 1 , further comprising a heating member for heating a recording medium to which the ejected ink droplet adheres.
20. An ink jet recording method using an ink jet recording apparatus according to claim 1 .