System for compensating for drop volume variation during three-dimensional printing of an object

Patent metadata

Field	Value
Publication number	US-9446556-B2
Application number	US-201414298153-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Jun 6, 2014
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A printer compensates for variations in ejected material drop volumes occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates topographical and measurement data of each layer of the object after each layer is printed. Differences in height between columns of material being formed by the ejectors in the printhead are identified with reference to the data produced by the sensor and raster data used to operate the printhead are modified adjust the formation of a next layer in the object.

First claim

What is claimed:

1. A printer comprising:
a platen;
a printhead configured with ejectors to eject material onto the platen;
an optical sensor configured to generate data corresponding to a topography and measurement of the material on the platen; and
a controller operatively connected to the optical sensor and the printhead, the controller being configured to generate raster image data for layers to be printed that form an object on the platen, to operate the printhead to eject material onto the platen with reference to the raster image data for the layers, and to modify raster image data for at least one ejector with reference to topographical and measurement data received from the optical sensor to compensate for variations in drop volumes between the at least one ejector and other ejectors in the printhead ejecting material.

2. The printer of claim 1 wherein the optical sensor is a blue laser sensor.

3. The printer of claim 1 wherein the platen is a planar member.

4. The printer of claim 1 , the controller being further configured to:
identify a difference in height between a column of material being formed by the at least one ejector and columns of material being formed by the other ejectors in the printhead with reference to the topographical and measurement data received from the optical sensor; and
modify the raster image data for the at least one ejector with reference to the identified difference.

5. The printer of claim 1 , the controller being further configured to:
add an additional voxel to the raster image data for the at least one ejector in response to the identified difference indicating the column of material formed by the at least one ejector is shorter than the columns of material formed by the other ejectors; and
operate the at least one ejector to eject a drop of material onto the column of material being formed by the at least one ejector with reference to the additional voxel while not operating the other ejectors to reduce the difference between the column of material being formed by the at least one ejector and the columns of material being formed by the other ejectors.

6. The printer of claim 1 , the controller being further configured to:
remove a voxel from the raster image data for the at least one ejector in response to the identified difference indicating the column of material formed by the at least one ejector is taller than the columns of material formed by the other ejectors; and
operate the other ejectors to eject a drop of material onto each column of material being formed by the other ejectors while not operating the at least one ejector to reduce the difference between the column of material being formed by the at least one ejector and the columns of material being formed by the other ejectors.

7. The printer of claim 5 , the controller being further configured to reduce a size of the material drop to be ejected by the at least one ejector with reference to the added voxel, the reduced size of the material drop being less than a size of the material drops ejected by the other ejectors.

8. The printer of claim 4 , the controller being further configured to reduce a size of the material drop to be ejected by the at least one ejector while operating the other ejectors to eject material drops with a size larger than the reduced size of the material drop ejected by the at least one ejector.

9. A printer comprising:
a platen;
a printhead configured with ejectors to eject material onto the platen;
an optical sensor configured to generate data corresponding to a topography and measurement of the material on the platen; and
a controller operatively connected to the optical sensor and the printhead, the controller being configured to operate the ejectors in the printhead to eject material drops onto the platen, to identify differences between volumes of material drops ejecting by the ejectors with reference to topographical and measurement data received from the optical sensor, and to move the printhead to form each column of material on the platen with material ejected from more than one ejector in the printhead to compensate for the identified differences in drop volumes.

10. The printer of claim 9 , the controller being further configured to move the printhead in a cross-process direction.

11. The printer of claim 9 wherein the optical sensor is a blue laser sensor.

12. The printer of claim 9 wherein the platen is a planar member.

13. The printer of claim 9 , the controller being further configured to:
generate raster image data for layers to be printed to form an object on the platen;
operate the printhead to eject material onto the platen with reference to the raster image data for the layers; and
modify raster image data for at least one ejector with reference to topographical and measurement data received from the optical sensor to compensate for the identified differences in drop volumes.

14. The printer of claim 13 , the controller being further configured to:
add an additional voxel to the raster image data for the at least one ejector in response to the identified differences in drop volumes indicating a column of material formed by the at least one ejector is shorter than columns of material formed by other ejectors in the printhead; and
operate the at least one ejector to eject a drop of material onto the column of material being formed by the at least one ejector with reference to the additional voxel while not operating the other ejectors to reduce the difference between the column of material being formed by the at least one ejector and the columns of material being formed by the other ejectors.

15. The printer of claim 13 , the controller being further configured to:
remove a voxel from the raster image data for the at least one ejector in response to the identified differences in drop volumes indicating a column of material formed by the at least one ejector is taller than columns of material formed by other ejectors in the printhead; and
operate the other ejectors to eject a drop of material onto each column of material being formed by the other ejectors while not operating the at least one ejector to reduce the difference between the column of material being formed by the at least one ejector and the columns of material being formed by the other ejectors.

16. The printer of claim 14 , the controller being further configured to reduce a size of the material drop to be ejected by the at least one ejector with reference to the added voxel, the reduced size of the material drop being less than a size of the material drops ejected by the other ejectors.

17. The printer of claim 13 , the controller being further configured to reduce a size of the material drop to be ejected by at least one ejector while operating other ejectors in the printhead to eject material drops with a size larger than the reduced size of the material drop ejected by the at least one ejector.

18. A non-transitory computer readable storage media on which programmed instructions for operating a printer having been stored, the programmed instructions being configured to enable a controller executing the programmed instructions to:
generate raster image data for layers to be printed that form an object on a platen;
operate a printhead with reference to the generated raster image data to eject material onto the platen to the object; and
compensate for variations in drop volumes between the at least one ejector and other ejectors in the printhead ejecting material to form the object by modifying the generated raster im

Assignees

• Xerox Corp

Inventors

• Hosier Paul A
• Triplett Roger L
• Schweid Stuart A
• Clingerman Terri A

Classifications

• B29C67/0059 Primary

  Operations & Transport · mapped topic

• B29C64/112 Primary

  using individual droplets, e.g. from jetting heads · CPC title