Printing apparatus, cleaning device of ink-jet head and cleaning method of ink-jet head

1. A printing apparatus comprising:

an ink-jet head comprising a nozzle plate with a nozzle string in which a plurality of nozzle holes for discharging ink are arranged; and

a cleaning device comprising an ink-repellent surface with ink repellency which is configured to come in contact with the nozzle plate in a state in which the ink-repellent surface is opposed to the ink-jet head, an ink-affinitive surface with ink affinity which is configured to create a gap between the ink-affinitive surface and the nozzle plate in a state in which the ink-repellent surface is in contact with the nozzle plate, and to have a smaller ink contact angle than the ink-repellent surface, and a plurality of suction ports formed in the ink-affinitive surface.

2. The printing apparatus of claim 1 , wherein when the suction nozzle is opposed to the ink-jet head, each of the suction ports is located at a position displaced from a position facing the nozzle holes.

3. The printing apparatus of claim 1 , wherein the plurality of suction ports comprise a first suction port and a second suction port which are located on both sides of a position facing the nozzle string.

4. The printing apparatus of claim 1 , wherein when a number of the nozzle strings is n, a number of the suction ports is at least (n+1) or more.

5. The printing apparatus of claim 1 , wherein a diameter of the suction port is greater than a diameter of the nozzle hole.

6. The printing apparatus of claim 1 , wherein the ink-repellent surface is located on each of both sides of the ink-affinitive surface.

7. The printing apparatus of claim 1 , wherein the suction nozzle comprises a guide configured to clamp the ink-jet head in a state in which the suction nozzle is opposed to the ink-jet head.

8. The printing apparatus of claim 1 , wherein the suction nozzle comprises a distal end portion which advances to a position facing the ink-jet head, the distal end portion being an inclined surface having an acute angle to an upper surface of the nozzle plate.

9. The printing apparatus of claim 1 , wherein a distance from an upper surface of the nozzle plate to the ink-affinitive surface, which distance defines the gap, is 0.05 mm or more, and 0.1 mm or less.

10. The printing apparatus of claim 1 , wherein an upper surface of the nozzle plate has ink repellency.

11. A cleaning device of an ink-jet head, the cleaning device comprising a suction nozzle comprising:

an ink-repellent surface with ink repellency;

an ink-affinitive surface with ink affinity which is configured to be recessed from the ink-repellent surface and to have a smaller ink contact angle than the ink-repellent surface; and

a plurality of suction ports formed in the ink-affinitive surface.

12. The cleaning device of claim 11 , wherein the ink-repellent surface is located on each of both sides of the ink-affinitive surface.

13. The cleaning device of claim 12 , wherein the suction nozzle further comprises a guide which is located on an outside of the ink-repellent surface and projects upward from the ink-repellent surface.

14. The cleaning device of claim 11 , wherein the suction nozzle further comprises an inclined surface which is bent downward from the ink-repellent surface and the ink-affinitive surface.

15. A cleaning method of an ink-jet head, comprising:

moving a suction nozzle, with an ink-repellent surface of the suction nozzle being in contact with a nozzle plate and a gap being created between an ink-affinitive surface of the suction nozzle and the nozzle plate, in a state in which the ink-jet head comprising the nozzle plate with a nozzle string, in which a plurality of nozzle holes for discharging ink are arranged, is opposed to the suction nozzle; and

sucking ink, which is drawn by an air flow in the gap, from a plurality of suction ports formed in the ink-affinitive surface.

16. The cleaning method of claim 15 , wherein each of the suction ports moves along a position displaced from a position facing the nozzle holes.

17. The cleaning method of claim 15 , wherein the plurality of suction ports move on both sides of a position facing the nozzle string.

18. The cleaning method of claim 15 , wherein the suction nozzle moves while clamping a mask plate of the ink-jet head.

19. The cleaning method of claim 15 , wherein the air flow is produced by taking air into the gap in a direction parallel to a direction of movement of the suction nozzle.