Ink discharging apparatus and ink discharging method

1. An ink discharging apparatus comprising:

an active-energy-ray-curable ink; and

an ink discharging head,

wherein the ink discharging head comprises:

liquid chambers;

a nozzle plate that comprises nozzle holes; and

a flow path,

wherein members of the ink discharging head to contact the active-energy-ray-curable ink are joined using an epoxy adhesive,

wherein the ink discharging head is configured to discharge the active-energy-ray-curable ink from the nozzle holes,

wherein the active-energy-ray-curable ink comprises at least any one selected from the group consisting of an acrylamide compound and an N-vinyl compound, and

wherein an elastic modulus decreasing rate represented by a formula (1) below is 50 percent or less,

Elastic modulus decreasing rate (%)={( E 1 −E 2 )/ E 1 }×100   formula (1)

where E 1 represents an elastic modulus (GPa) of a cured product obtained by curing the epoxy adhesive at 90 degrees C. for 4 hours, and E 2 represents an elastic modulus (GPa) of an immersed product obtained by immersing the cured product in the active-energy-ray-curable ink at 60 degrees C. for 4 weeks.

2. The ink discharging apparatus according to claim 1 ,

wherein the acrylamide compound comprises acryloylmorpholine, and

wherein the N-vinyl compound comprises N-vinylcaprolactam.

3. The ink discharging apparatus according to claim 1 ,

wherein the elastic modulus decreasing rate of the cured product is 10 percent or less.

4. The ink discharging apparatus according to claim 1 ,

wherein a content of epoxy group in the epoxy adhesive before cured is 0.4 mol/100 g or greater.

5. The ink discharging apparatus according to claim 1 ,

wherein a total of contents of the acrylamide compound and the N-vinyl compound is 30 percent by mass or greater of a total amount of the active-energy-ray-curable ink.

6. The ink discharging apparatus according to claim 1 ,

wherein the members that are to contact the active-energy-ray-curable ink and are joined using the epoxy adhesive comprise at least any one selected from the group consisting of the nozzle plate, a flow path plate, and a vibration plate.

7. An ink discharging apparatus comprising:

an active-energy-ray-curable ink; and

an ink discharging head,

wherein the ink discharging head comprises:

liquid chambers;

a nozzle plate that comprises nozzle holes; and

a flow path,

wherein members of the ink discharging head to contact the active-energy-ray-curable ink are joined using an epoxy adhesive,

wherein the ink discharging head is configured to discharge the active-energy-ray-curable ink from the nozzle holes,

wherein the active-energy-ray-curable ink comprises at least any one selected from the group consisting of an acrylamide compound and an N-vinyl compound, and

wherein a Martens hardness decreasing rate represented by a formula (2) below is 50 percent or less,

Martens hardness decreasing rate (%)={( M 1 −M 2 )/ M 1 }×100   formula (2)

where M 1 represents a Martens hardness (N/mm 2 ) of a cured product obtained by curing the epoxy adhesive at 90 degrees C. for 4 hours, and M 2 represents a Martens hardness (N/mm 2 ) of an immersed product obtained by immersing the cured product in the active-energy-ray-curable ink at 60 degrees C. for 4 weeks.

8. The ink discharging apparatus according to claim 7 ,

wherein the acrylamide compound comprises acryloylmorpholine, and

wherein the N-vinyl compound comprises N-vinylcaprolactam.

9. The ink discharging apparatus according to claim 7 ,

wherein the Martens hardness decreasing rate of the cured product is 10 percent or less.

10. An ink discharging method comprising

forming an image using an ink discharging apparatus that comprises:

an active-energy-ray-curable ink; and

an ink discharging head,

wherein the ink discharging head comprises:

liquid chambers;

a nozzle plate that comprises nozzle holes; and

a flow path,

wherein members of the ink discharging head to contact the active-energy-ray-curable ink are joined using an epoxy adhesive,

wherein the ink discharging head is configured to discharge the active-energy-ray-curable ink from the nozzle holes,

wherein the active-energy-ray-curable ink comprises at least any one selected from the group consisting of an acrylamide compound and an N-vinyl compound, and

wherein an elastic modulus decreasing rate represented by a formula (1) below is 50 percent or less,

Elastic modulus decreasing rate (%)={( E 1 −E 2 )/ E 1 }×100   formula (1)

where E 1 represents an elastic modulus (GPa) of a cured product obtained by curing the epoxy adhesive at 90 degrees C. for 4 hours, and E 2 represents an elastic modulus (GPa) of an immersed product obtained by immersing the cured product in the active-energy-ray-curable ink at 60 degrees C. for 4 weeks.

11. The ink discharging method according to claim 10 ,

wherein the acrylamide compound comprises acryloylmorpholine, and

wherein the N-vinyl compound comprises N-vinylcaprolactam.

12. The ink discharging method according to claim 10 ,

wherein the elastic modulus decreasing rate of the cured product is 10 percent or less.

13. The ink discharging method according to claim 10 ,

wherein a content of epoxy group in the epoxy adhesive before cured is 0.4 mol/100 g or greater.

14. The ink discharging method according to claim 10 ,

wherein a total of contents of the acrylamide compound and the N-vinyl compound is 30 percent by mass or greater of a total amount of the active-energy-ray-curable ink.

15. The ink discharging method according to claim 10 ,

wherein the members that are to contact the active-energy-ray-curable ink and are joined using the epoxy adhesive comprise at least any one selected from the group consisting of the nozzle plate, a flow path plate, and a vibration plate.