Controlling line widths in flexographic printing

Patent metadata

Field	Value
Publication number	US-9327489-B2
Application number	US-201414162828-A
Country	US
Kind code	B2
Filing date	Jan 24, 2014
Priority date	Jan 24, 2014
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

A method for controlling feature characteristics in a flexographic printing system that forms a printed pattern on a substrate by applying ink from an ink reservoir using a flexographic printing plate mounted on a plate cylinder. An imaging system is used to capture an image of the pattern printed on the substrate, and the captured image is analyzed to determine a feature characteristic of one or more features of the printed pattern. A control system automatically controls an amount of solvent used to replenish the ink in the ink reservoir responsive to the determined feature characteristic.

First claim

The invention claimed is:

1. A method for controlling feature characteristics in a flexographic printing system, comprising:
using the flexographic printing system to form a printed pattern on a substrate by applying ink from an ink reservoir using a flexographic printing plate mounted on a plate cylinder, wherein the flexographic printing plate has raised features corresponding to the printed pattern;
using an imaging system to capture an image of the pattern printed on the substrate;
analyzing the capture image to determine a feature characteristic of one or more features of the printed pattern; and
using a control system to automatically control an amount of solvent used to replenish the ink in the ink reservoir responsive to the determined feature characteristic, wherein the feature characteristic is a line width.

2. The method of claim 1 , wherein the amount of solvent used to replenish the ink is controlled by adjusting a flow rate at which the solvent is added to the ink.

3. The method of claim 2 , wherein the flow rate of the solvent is controlled such that variations of the feature characteristic as a function of time are reduced relative to a target feature characteristic.

4. The method of claim 1 , wherein the line width is between 2 microns and 10 microns.

5. The method of claim 1 , wherein an ink recirculation system is used to replenish the ink in the ink reservoir, the ink recirculation system including:
an ink recirculation line that is connected to the ink recirculation ports of the ink reservoir;
a solvent replenishment chamber containing solvent;
a metering pump for pumping a controlled flow rate of solvent from the solvent replenishment chamber into the ink recirculation line thereby providing replenished ink;
a control system for controlling the flow rate of solvent provided by metering pump; and
a recirculation pump for moving ink through the ink recirculation line and returning the replenished ink to the ink reservoir.

6. The method of claim 5 , wherein the ink recirculation system further includes a distribution tube that receives the replenished ink from the ink recirculation line and supplies the replenished ink to the ink reservoir, wherein the distribution tube includes a plurality of supply ports for supplying the replenished ink to the ink reservoir at a plurality of spaced apart locations across a width of the ink reservoir.

7. The method of claim 5 , wherein the ink recirculation system further includes a mixing device for mixing the solvent and the ink to provide the replenished ink.

8. The method of claim 7 , wherein the mixing device includes a static inline mixer.

9. The method of claim 7 , wherein the mixing device includes a dynamic mixing device.

10. The method of claim 5 , wherein the recirculation pump is a peristaltic pump.

11. The method of claim 5 , wherein the flexographic printing system includes a plurality of print modules each including a corresponding ink reservoir and a corresponding flexographic printing plate, and wherein at least a portion of the ink recirculation system is shared among the plurality of print modules.

12. The method of claim 1 , wherein the flexographic printing system includes a plurality of print modules each including a corresponding ink reservoir and a corresponding flexographic printing plate, and wherein a flow rate of the solvent is independently controlled for at least two of the print modules.

13. The method of claim 1 , wherein the flexographic printing system includes a dynamic ink reservoir mixing device disposed within the ink reservoir.

14. The method of claim 1 , wherein a viscosity of the ink is between 10 centipoises and 20,000 centipoises.

15. The method of claim 1 , wherein the ink reservoir is an ink pan.

16. The method of claim 15 , wherein an anilox roller is used to transfer ink from the ink reservoir to the flexographic printing plate, and wherein a fountain roller that is at least partially immersed in the ink in the ink pan is used to transfer ink to the anilox roller.

17. The method of claim 1 , wherein the ink reservoir is an ink reservoir chamber.

Assignees

• Shifley James Douglas
• Alexandrovich Peter Steven
• Reczek James Albert
• Eastman Kodak Co

Inventors

• Shifley James Douglas
• Alexandrovich Peter Steven
• Reczek James Albert

Classifications

• B41F31/06

  Troughs or like reservoirs with immersed or partly immersed, rollers or cylinders · CPC title

• B41F31/20

  Ink-removing or collecting devices · CPC title

• B41P2251/112

  Peristaltic pumps · CPC title

• B41F31/005

  Ink viscosity control means · CPC title

• Y10T428/24802

  Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.] · CPC title