Methods for printing a curved surface of an object by using an inkjet head

1. A method for printing at least one section of a curved surface of an object, the method comprising the following steps:

providing an inkjet head having a row of nozzles expelling ink;

providing an articulated-arm robot for moving the inkjet head;

carrying out a relative movement between the inkjet head and the curved surface of the object to move the inkjet head along a first path while printing a first track and to subsequently move the inkjet head along a second path while printing a second track, at least one of the first track or the second track having a curve; and

causing a first track edge of the first track and a second track edge of the second track to intersect at a point and to enclose an angle between about 1° and about 179° at the point.

2. The method according to claim 1 , wherein the angle lies between about 20° and about 70°.

3. The method according to claim 1 , wherein the angle lies between about 110° and about 160°.

4. The method according to claim 1 , wherein the angle lies at about 45°.

5. The method according to claim 1 , wherein the angle lies at about 135°.

6. The method according to claim 1 , wherein the first path and the second path overlap in an overlap area.

7. The method according to claim 6 , wherein the inkjet head prints only on the first path or on the second path in at least part of the overlap area.

8. The method according to claim 6 , wherein the inkjet head prints on the first path and does not print on the second path in the whole of the overlap area.

9. The method according to claim 7 , wherein the second path crosses the first path in the overlap area.

10. The method according to claim 8 , wherein the second path crosses the first path in the overlap area.

11. The method according to claim 9 , wherein the second path and the first path cross in a plurality of overlap areas.

12. The method according to claim 10 , wherein the second path and the first path cross in a plurality of overlap areas.

13. The method according to claim 11 , wherein the at least one section of the surface of the object is assembled substantially from overlap areas.

14. The method according to claim 12 , wherein the at least one section of the surface of the object is assembled substantially from overlap areas.

15. The method according to claim 1 , which further comprises changing an orientation of the inkjet head relative to a respective one of the paths while the inkjet head is on at least one of the paths.

16. A method for printing at least one section of a curved surface of an object, the method comprising the following steps:

providing an inkjet head having a row of nozzles expelling ink;

providing an articulated-arm robot for moving the inkjet head;

moving the inkjet head along a first path while printing a first track on the curved surface of the object;

subsequently moving the inkjet head along a second path while printing a second track on the curved surface of the object;

providing at least one of the first track or the second track with a curve; and

changing an orientation of the inkjet head relative to a respective one of the paths while the inkjet head is on at least one of the paths.

17. The method according to claim 16 , which further comprises rotating the inkjet head about an axis during a forward movement of the inkjet head on at least one of the paths.

18. The method according to claim 17 , wherein the axis is perpendicular to an area of at least one of the tracks.