Method for inkjet printing on at least one curved region of a surface of an object and device for implementing the method

Patent metadata

Field	Value
Publication number	US-9833990-B2
Application number	US-201715427192-A
Country	US
Kind code	B2
Filing date	Feb 8, 2017
Priority date	Feb 17, 2016
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A method for inkjet printing an image onto a curved region of an object surface includes applying a screen of ink drops to the region to create print dots, calculating the screen using a computer and generating and applying ink drops to the region using a print head having nozzles on a nozzle surface. The steps include a) providing data representing the print image, b) providing or calculating data representing the region, c) providing or calculating path data on paths for the print head or object, d) calculating application locations of ink drops using data from steps b) and c), e) calculating data based on tiling the region using data from step d), f) calibrating tone values using data from step e), g) screening the print image using data from step f), and h) printing the screened image onto the region. A device implementing the method is also provided.

First claim

The invention claimed is:

1. A method for inkjet printing a print image onto at least one curved region of a surface of an object, the method comprising the following steps:
applying a screen of ink drops to a region to create print dots by calculating the screen using a computer, and creating and applying the ink drops to the region using nozzles of a nozzle surface of a print head;
carrying out the following steps a) to g) on the computer:
a) providing data representing the print image;
b) providing or calculating data representing the region;
c) providing or calculating path data on paths on which the print head or the object moves;
d) calculating application locations of the ink drops using the data from steps b) and c);
e) calculating data based on a tiling of the region using data from step d);
f) calibrating tone values using the data of step e);
g) screening the print image using data from step f); and carrying out the following step h) by using the print head:
h) printing the screened image onto the region.

2. The method according to claim 1 , wherein step d) includes a step d1) of projecting the locations of the nozzles onto the surface.

3. The method according to claim 2 , wherein step d) includes a step d2) of correcting the projection by factoring in at least an application speed of the ink drops relative to the surface.

4. The method according to claim 1 , wherein step e) includes a step e1) of assigning irregular tiles to the print dots, and a step e2) of calculating surface areas of the respective tiles.

5. The method according to claim 1 , wherein step f) includes using a calibration function that is dependent on the tone values and on surface areas of the tiles.

6. The method according to claim 1 , wherein step g) includes either:
g1) re-projecting the locations of the print dots onto the nozzle surface and g2) screening using a 2D screen process, or
g3) screening using a 3D screen process and g4) re-projecting the locations of the print dots onto the nozzle surface.

7. The method according to claim 1 , which further comprises carrying out an additional step B′ of mapping the print image onto the surface.

8. A device for inkjet printing a print image onto at least one curved region of a surface of an object, the device comprising:
a robot, a print head, and a computer;
said computer implementing steps a) to g) of claim 1 and subsequently actuating said robot and said print head; and
said print head generating ink drops while said robot carries out a movement.

Assignees

• Heidelberger Druckmasch Ag

Inventors

• Rupprecht Andreas
• Fuener Michael
• Mueller Tobias

Classifications

• B41J3/4073 Primary

  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) · CPC title

• G06K15/1825

  Adapting the print data to an output condition, e.g. object trapping (trapping on rasterized data H04N1/58) · CPC title

• B41J2/04586

  controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type · CPC title

• B41J2/04536 Primary

  using history data · CPC title

• B41M5/0088

  by ink-jet printing · CPC title