IMAGE PROCESSING METHOD FOR THREE-DIMENSIONAL PRINTING

• US 20110249048A1
• Filed: 12/01/2009
• Published: 10/13/2011
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: Agfa Nv (Agfa-Gevaert N.V.)
• Original Assignee: Agfa Graphics Nv (Agfa-Gevaert N.V.)
• Inventors: Lenders, Rudi, Gullentops, Chris
• Granted Patent: US 8,705,144 B2
• Time in Patent Office: Days
• US Class Current: 347/5
• CPC Class Codes: B29C 64/112 using individual droplets, e.g. from jetting heads
• CPC Class Codes: B29C 64/386 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B41C 1/003 the relief or intaglio pattern being obtained by imagewise deposition of a liquid, e.g. by an ink jet
• CPC Class Codes: B41J 29/38 Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
• CPC Class Codes: H04N 1/40081 Soft dot halftoning, i.e. producing halftone dots with gradual edges

Abstract

A relief print master is created by printing a sequence of layers on top of each other by an inkjet printing system. The top layer corresponds with the binary halftoned image that is to be printed by the print master and the lower intermediate layers are supporting layers. The features in a lower supporting layer have an area that is larger than the corresponding features in a higher supporting layer. A circular spread function is applied on the features of a higher intermediate layer to increase the area of the features in a lower intermediate layer. By using a sequence of two non-circular spread functions, the circular spread function is approximated and the number of required calculations can be reduced.

Claims

1-11. -11. (canceled)

12. A method for calculating a series of intermediate bitmaps corresponding to a series of intermediate layers for creating a relief print master for printing a digital image, the method comprising the steps of:

calculating a halftone bitmap of the digital image, the halftone bitmap representing a first intermediate bitmap; and

calculating from the first intermediate bitmap a series of intermediate bitmaps by applying a spread function on a previous intermediate bitmap to obtain a next intermediate bitmap;

wherein

the step of calculating the series of intermediate bitmaps includes using an alternate sequence of a first spread function and a second spread function that is different from the first spread function.

13. The method according to claim 12, wherein the first spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of the previous intermediate bitmap.

14. The method according to the claim 12, wherein the second spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of the next intermediate bitmap and in four directions diagonal to the XY grid.

15. The method according to the claim 13, wherein the second spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of then next intermediate bitmap and in four directions diagonal to the XY grid.

24. A system for creating a relief print master on a substrate for printing a digital image by printing a series of intermediate layers from a series of intermediate bitmaps, the system comprising:

a print head arranged to move in XY directions relative to the substrate to print the series of intermediate bitmaps; and

a computer to calculate the series of intermediate bitmaps according to claim 12.

25. A system for creating a relief print master on a substrate for printing a digital image by printing a series of intermediate layers from a series of intermediate bitmaps, the system comprising:

a print head arranged to move in XY directions relative to the substrate to print the series of intermediate bitmaps; and

a computer to calculate the series of intermediate bitmaps according to claim 13.

26. A system for creating a relief print master on a substrate for printing a digital image by printing a series of intermediate layers from a series of intermediate bitmaps, the system comprising:

a print head arranged to move in XY directions relative to the substrate to print the series of intermediate bitmaps; and

a computer to calculate the series of intermediate bitmaps according to claim 14.

27. A system for creating a relief print master on a substrate for printing a digital image by printing a series of intermediate layers from a series of intermediate bitmaps, the system comprising:

a print head arranged to move in XY directions relative to the substrate to print the series of intermediate bitmaps; and

a computer to calculate the series of intermediate bitmaps according to claim 15.

28. The system according to claim 24, further comprising a curing source to cure a previous intermediate layer before a next intermediate layer is printed.

29. The system according to claim 25, further comprising a curing source to cure a previous intermediate layer before a next intermediate layer is printed.

30. The system according to claim 26, further comprising a curing source to cure a previous intermediate layer before a next intermediate layer is printed.

31. The system according to claim 27, further comprising a curing source to cure a previous intermediate layer before a next intermediate layer is printed.

16. A method for creating a relief print master for printing a digital image using a series of intermediate bitmaps, the method comprising the steps of:

calculating a halftone bitmap of the digital image, the halftone bitmap representing a first intermediate bitmap;

calculating from the first intermediate bitmap a series of intermediate bitmaps by applying a spread function on a previous intermediate bitmap to obtain a next intermediate bitmap; and

printing the series of intermediate bitmaps in an opposite order in which the series of intermediate bitmaps were calculated to obtain a plurality of intermediate layers;

wherein

the step of calculating the series of intermediate bitmaps includes using an alternate sequence of a first spread function and a second spread function that is different from the first spread function.

17. The method according to claim 16, wherein the first spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of the previous intermediate bitmap.

18. The method according to claim 16, wherein the second spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of the next intermediate bitmap and in four directions diagonal to the XY grid.

19. The method according to claim 17, wherein the second spread function includes:

generating next to each pixel that corresponds to printing ink in the series of intermediate bitmaps an additional pixel for printing ink in four directions corresponding to an XY grid of the next intermediate bitmap and in four directions diagonal to the XY grid.

20. The method according to the claim 16, wherein a previous intermediate layer is cured before a next intermediate layer is printed.

21. The method according to the claim 17, wherein a previous intermediate layer is cured before a next intermediate layer is printed.

22. The method according to the claim 18, wherein a previous intermediate layer is cured before a next intermediate layer is printed.

23. The method according to the claim 19, wherein a previous intermediate layer is cured before a next intermediate layer is printed.

32. A method for applying a circular spread function on an object in an image including pixels, the object including a first color that is different from a second background color, the method comprising a sequence of the following two steps in either order:

generating next to each pixel that corresponds to the first color in a bitmap an additional pixel of the same first color in four directions corresponding to an XY grid of the bitmap and in four directions diagonal to the XY grid to obtain an intermediate bitmap; and

generating next to each pixel that corresponds to the first color in the intermediate bitmap an additional pixel of the same first color in the four directions corresponding to the XY grid of the bitmap.