SYSTEM AND METHOD FOR DECREASING TIME FOR PRINTING LAYERS IN THREE-DIMENSIONAL OBJECTS AND FOR ENHANCING COLOR FIDELITY AT THE SURFACE OF THREE-DIMENSIONAL OBJECTS

• US 20180229447A1
• Filed: 02/16/2017
• Published: 08/16/2018
• Est. Priority Date: 02/16/2017
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Mantell, David A., Schweid, Stuart A.
• Granted Patent: US 10,457,034 B2
• Time in Patent Office: Days
• 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: B29C 64/393 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B29K 2105/0058 Liquid or visquous
• CPC Class Codes: B29K 2995/002 Coloured
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: H04N 1/60 Colour correction or control H04N1/54 takes precedence

Abstract

A three-dimensional object printer has a controller that operates pluralities of ejectors ejecting drops of different materials having different colors, at least one color of which is white, to produce objects with different levels of color saturation. The controller operates the pluralities of ejectors with reference to a function of a sum of an average number of drops per voxel in each layer, a target value of an average number of drops per voxel of colorants other than white in each layer, and a distance from a closest surface of the object for each material ejected by the ejectors. At a predetermined distance from a closest surface and greater, the controller operates the pluralities of ejectors to form voxels in layers of the object with only clear and white drops. At distances less than the predetermined distance, the number of clear drops increases and the number of white drops decreases.

Claims

1. A system comprising:

a first plurality of ejectors configured to eject drops of a first material having a first color;

a second plurality of ejectors configured to eject drops of a second material having a second color, the first color being different than the second color;

a third plurality of ejectors configured to eject drops of a third material having a third color, the third color being different than the second color and the first color;

at least one actuator operatively connected to the first plurality of ejectors, the second plurality of ejectors, and the third plurality of ejectors; and

a controller operatively connected to the at least one actuator, the first plurality of ejectors, the second plurality of ejectors, and the third plurality of ejectors, the controller being configured to;

identify an average number of material drops per voxel for each material in each layer of an object to be manufactured;

convert image data for the object to material drop data for each of the first material, the second material, and the third material with reference to a first function of a sum of the average number of second material drops per voxel of each layer and the average number of third material drops per voxel in each layer, a target value for the sum of the average number of material drops per voxel of all materials, and a distance between the layer and a closest surface of the object;

converting the material drop data to drop data that identifies material drops for each voxel in each layer; and

operating with reference to the converted material drop data the first plurality of ejectors, the second plurality of ejectors, and the third plurality of ejectors to eject drops of the first material, drops of the second material, and drops of the third material to form the layers of the object corresponding to the image data.

2. The system of claim 1, the controller being further configured to operate the at least one actuator to move the first plurality of ejectors, the second plurality of ejectors, and the third plurality of ejectors to position the pluralities of ejectors for ejecting material drops into voxels of each layer of the object.

3. The system of claim 1, the first plurality of ejectors being configured to eject white material drops.

4. The system of claim 3 further comprising:

a fourth plurality of ejectors configured to eject drops of a fourth material that is clear, which is a different color than the white material drops, the second color, and the third color.

5. The system of claim 4, the controller being further configured to convert the image data for the object to material drop data by calculating material drop data for clear fourth material with reference to a second function of an output of the first function and a distance between the layer and a closest surface of the object.

6. The system of claim 5 wherein the second function has a negative second derivative.

7. The system of claim 5 where the second function is a difference between the target value for the sum of the average number of material drops per voxel of all materials and a sum of the average number of drops per voxel of the first, second, and third materials.

8. The system of claim 7 where the target value for the sum of the average number of material drops per voxel of all materials is greater than one.

9. The system of claim 7 wherein the average number of material drops per voxel of the second and the third materials are increased from an initial average number of material drops at distances from a surface for which the output of the first function is zero for the first material.

10. The system of claim 1 further comprising:

a fourth plurality of ejectors configured to eject drops of a fourth material having a magenta color;

a fifth plurality of ejectors configured to eject drops of a fifth material having a black color; and

wherein the second plurality of ejectors are configured to eject the drops of second material having a cyan color, and the third plurality of ejectors are configured to eject the drops of the third material having a yellow color; and

the sum of the average number of second material drops per voxel of each layer and the average number of third material drops per voxel in each layer includes the average number of fourth material drops per voxel in each layer and the average number of fifth material drops per voxel in each layer.

11. The system of claim 1 wherein the first function monotonically increases the average number of first material drops in each layer of the object as the distance between the layer and a surface of the object increases.

12. The system of claim 1 wherein the first function has a positive or zero second derivative.

13. The system of claim 4 wherein the material drop data for layers at a predetermined distance from a closest surface or greater corresponds to white material drops and clear material drops only.

14. The system of claim 13 wherein the clear material drop data for layers less than the predetermined distance from the closest surface increases and the white material drop data for layers less than the predetermined distance from the closest surface decreases.

15. A method for operating a printer comprising:

identifying with a controller an average number of material drops per voxel for each material in each layer of an object to be manufactured;

converting with the controller image data for the object to material drop data for each of a first material, a second material, and a third material with reference to a first function of a sum of the identified average number of second material drops per voxel of each layer and the identified average number of third material drops per voxel in each layer, a target value for the sum of the identified average number of material drops per voxel of all materials, and a distance between the layer and a closest surface of the object;

converting with the controller the material drop data to drop data that identifies material drops for each voxel in each layer; and

operating a first plurality of ejectors, a second plurality of ejectors, and a third plurality of ejectors with the controller with reference to the converted material drop data to eject drops of the first material, drops of the second material, and drops of the third material to form the layers of the object corresponding to the image data, each plurality of ejectors ejecting material drops have a color different than a color of the material drops ejected by the other pluralities of ejectors.

16. The method of claim 15 further comprising:

operating with the controller at least one actuator to move the first plurality of ejectors, the second plurality of ejectors, and the third plurality of ejectors to position the pluralities of ejectors for ejecting material drops into voxels of each layer of the object.

17. The method of claim 15 wherein operation of the first plurality of ejectors ejects white material drops.

18. The method of claim 17 further comprising:

operating with the controller a fourth plurality of ejectors to eject drops of a fourth material that is clear, which is a different color than the white material drops, the colors of the material drops ejected by the second plurality of ejectors and the third plurality of ejectors.

19. The method of claim 18 further comprising:

converting the image data for the object to material drop data with the controller by calculating material drop data for the clear fourth material with reference to a second function of an output of the first function and a distance between the layer and a closest surface of the object.

20. The method of claim 19 wherein the second function has a negative second derivative.