Three-dimensional object printing apparatus and method

• US 20010019340A1
• Filed: 02/27/2001
• Published: 09/06/2001
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Yamamoto, Koji, Kubo, Naoki, Nakanishi, Hideaki, Koreishi, Jun
• Granted Patent: US 6,460,958 B2
• Time in Patent Office: Days
• US Class Current: 347/1
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: B41J 3/00 Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed
• CPC Class Codes: B41J 3/4073 Printing on three-dimensional objects not being in sheet or web form, e.g. spherical or cubic objects B41J3/283, B41J3/286 take precedence; building up a 3D object using individual droplets from jetting heads B29C64/112

Abstract

Ejection nozzles (152a-152g) are located in a nozzle surface (153) of an ejection head (150). A distance (H: Ha-Hg) between each of the ejection nozzles (152a-152g) and a printing object (109) is obtained and compared with a permissible distance (H0) which is determined by the required level of print quality. The ejection nozzles (152a-152d) whose distances (H) from the printing object (109) are not more than the permissible distance (H0) are enabled for ink ejection, while the ejection nozzles (152e-152g) whose distances (H) are greater than the permissible distance (H0) are disabled for ink ejection. The surface of a printing object (228) is divided into a plurality of target areas (205), each of which is then approximated by a projective plane (206). Then, image data about a projected image (208) which is obtained by orthogonal projection of a print image (207) onto the projective planes (206), is obtained from print image data about an image to be printed on the surface of the printing object (228). According to the projected image data obtained, printing is performed on the target area (205) while moving a ink-jet printhead (210) in parallel with the projective planes (206). This inhibits image degradation during printing on a three-dimensional printing object and also facilitates control of the inclination and position of the ejection head relative to the printing object, thereby permitting high-speed printing.

Claims

1. An apparatus for supplying ink to a surface of a three-dimensional object, comprising:

a holding section for holding said three-dimensional object in any desired attitude with respect to three axial directions;

an ejection section for ejecting ink;

a mechanism for positioning said ejection section in any desired three-dimensional position while maintaining the attitude thereof with respect to said three-dimensional object which is held by said holding section; and

a controller for controlling said mechanism such that said ejection section performs two-dimensional scanning of a predetermined area of said three-dimensional object which is held in a certain attitude.

2. An apparatus for supplying ink to a surface of a three-dimensional object, comprising:

an ejection section for ejecting ink;

a mechanism for changing relative positions and relative attitudes of said ejection section and said three-dimensional object;

a processing section for approximating a predetermined area of the surface of said three-dimensional object by a flat face; and

a controller for controlling said mechanism to change said relative positions of said ejection section and said three-dimensional object while maintaining said relative attitudes thereof in a plane parallel to said flat face.

3. The apparatus according to

claim 2

, wherein said controller controls ink ejection by said ejection section at the same time as controlling said mechanism, so that a predetermined image is printed on said predetermined area.

4. The apparatus according to

claim 3

, further comprising:

an image generation section for generating a projected image by projecting said predetermined image onto said flat face, wherein

said controller controls said mechanism and said ejection section on the basis of said projected image generated by said image generation section.

5. The apparatus according to

claim 2

, wherein

for representing the surface of said three-dimensional object as a three-dimensional model made of a plurality of polygons, said processing section divides the surface of said three-dimensional object into a plurality of predetermined areas and approximates each of said predetermined areas by a flat face.

6. The apparatus according to

claim 5

, wherein

said processing section approximates each of said predetermined areas by a flat face within predetermined approximation errors.

7. The apparatus according to

claim 6

, wherein

said predetermined approximation errors are specified by a user.

8. The apparatus according to

claim 6

, wherein

said predetermined approximation errors correspond to a difference of altitude of said predetermined area approximated by said flat face.

9. The apparatus according to

claim 6

, wherein

said predetermined approximation errors correspond to the angle between said flat face and said predetermined area.

10. The apparatus according to

claim 2

, wherein

said ejection section comprises an ink-jet printhead for ejecting ink, and

when said flat face is held perpendicularly to a direction of ink ejection from said ink-jet printhead, said controller controls said mechanism such that said ink-jet printhead performs two-dimensional scanning in a plane parallel to said flat face.

11. The apparatus according to

claim 10

, wherein

said controller controls ink ejection by said ink-jet printhead as well as said two-dimensional scanning in response to an image to be printed on said flat face.

12. A method of supplying ink to a surface of a three-dimensional object, comprising the steps of:

a) approximating a portion of the surface of said three-dimensional object by a flat face;

b) fixing the inclination of said flat face of said step a) to a predetermined inclination; and

c) supplying ink to the surface of said three-dimensional object while performing two-dimensional scanning in a plane parallel to said flat face of said step b).

13. The method according to

claim 12

, wherein

said step a) includes the step of approximating a plurality of portions of said three-dimensional object respectively by flat faces thereby to approximate said three-dimensional object by a polyhedron made of a plurality of polygons, and

said steps b) and c) are repeatedly performed at the conclusion of scanning of each of said flat faces, so that ink is supplied to said plurality of polygons in sequence.

14. An apparatus for supplying ink to a surface of a three-dimensional object, comprising:

an ejection head with a plurality of nozzles for ejecting ink to the surface of said three-dimensional object located opposite said nozzles;

a scanning section for causing said ejection head to scan the surface of said three-dimensional object; and

a controller for enabling predetermined nozzles and disabling the other nozzles out of said plurality of nozzles in accordance with a shape of the surface of said three-dimensional object located opposite said ejection head, thereby to control scanning by said scanning section and ink ejection by said ejection head.

15. The apparatus according to

claim 14

, wherein

said scanning section causes said ejection head to perform scanning in close proximity to said three-dimensional object while maintaining a minimum clearance therebetween, and

said controller disables nozzles which are at more than a predetermined permissible distance away from the surface of said three-dimensional object, out of said plurality of nozzles.

16. The apparatus according to

claim 15

, wherein

said permissible distance is variable.

17. The apparatus according to

claim 16

, wherein

said permissible distance varies according to the setting determined by an operator.

18. The apparatus according to

claim 16

, wherein

said permissible distance varies according to the shape of said three-dimensional object.

19. The apparatus according to

claim 16

, wherein

said permissible distance varies according to an image to be printed on the surface of said three-dimensional object.

20. The apparatus according to

claim 19

, wherein

said permissible distance is set shorter in an edge portion of said image than in the other portions thereof.

21. The apparatus according to

claim 15

, further comprising:

a changing section for changing the attitudes of said ejection head and said three-dimensional object.

22. The apparatus according to

claim 21

, wherein

said changing section changes said attitudes so as to increase the number of nozzles to be enabled out of said plurality of nozzles.

23. The apparatus according to

claim 14

, wherein

said controller approximates said three-dimensional object by a three-dimensional model made of a plurality of polygons and determines nozzles to be enabled out of said plurality of nozzles for each of said polygons.

24. The apparatus according to

claim 15

, wherein

said scanning section is so configured as to cause said ejection head to perform linear scanning within a predetermined range in part of its scanning operation, and

said controller controls ink ejection during said linear scanning by using only nozzles which are enabled at all times during said linear scanning within said predetermined range.

25. An apparatus for supplying ink to a surface of a three-dimensional object, comprising:

a table to place said three-dimensional object, said table being rotatable about an axis perpendicular to a placing surface of said table;

an ejection head with a plurality of nozzles for ejecting ink, said ejection head being capable of being positioned in any desired position in three-dimensional space; and

a controller for controlling ink ejection by said ejection head in response to rotation of said table, by rotating said table with said ejection head in a predetermined position in three-dimensional space so that ink is supplied to said three-dimensional object with a predetermined width in a direction of said axis.

26. A method of supplying ink to a surface of a three-dimensional object, comprising the steps of:

a) locating said three-dimensional object opposite an ejection head with a plurality of nozzles for ejecting ink;

b) causing said ejection head to scan the surface of said three-dimensional object; and

c) enabling predetermined nozzles and disabling the other nozzles out of said plurality of nozzles in accordance with a shape of the surface of said three-dimensional object located opposite said ejection head, thereby to eject ink from said enabled nozzles during said scanning.

27. The method according to

claim 26

, wherein

said step b) includes the step of causing said ejection head to perform scanning in close proximity to said three-dimensional object while maintaining a minimum clearance therebetween, and

said step c) is for disabling nozzles which are at more than a predetermined permissible distance away from the surface of said three-dimensional object, out of said plurality of nozzles.

28. The method according to

claim 26

, wherein

said step c) includes the step of approximating said three-dimensional object by a three-dimensional model made of a plurality of polygons and determining nozzles to be enabled out of said plurality of nozzles for each of said polygons.

29. A method of supplying ink to a surface of a three-dimensional object, comprising the steps of:

placing said three-dimensional object on a table which is rotatable about an axis perpendicular to a placing surface of said table; and

rotating said table with an ejection head with a plurality of nozzles for ejecting ink being in a predetermined position in three-dimensional space, and ejecting ink from said ejection head in response to rotation of said table so that ink is supplied to said three-dimensional object with a predetermined width in a direction of said axis.