Fountain solution thickness measurement using a hot wire anemometer in a lithography printing system

Patent metadata

Field	Value
Publication number	US-11320737-B1
Application number	US-202017137711-A
Country	US
Kind code	B1
Filing date	Dec 30, 2020
Priority date	Dec 30, 2020
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

According to aspects of the embodiments, there is provided a method of measuring the amount of fountain solution using a hot wire anemometer. Fountain solution thickness is measured using the flow rate of vaporized fountain solution and comparing to baseline air only flow rate. The vaporized measurement is correlated with the baseline utilizing specific heat, density and enthalpy values and keeping velocity of fluid constant. Changes in the measurement will then be related to the specific heat, density and enthalpy. Density can be back calculated to yield volume and knowing the area of the image being printed give a real time thickness value.

First claim

What is claimed is:

1. A method useful in printing with a variable data lithography system, comprising:
using a dampening station configured to provide fountain solution in an airborne state to a reimageable surface;
performing an assessment check, including taking a base line measurement of air flow, and storing said base line measurement in a memory;
taking an operational measurement of the air flow with a flow measurement device during application of the fountain solution in an airborne state to the reimageable surface;
determining fountain solution thickness at the reimageable surface from a difference between the operational measurement and the base line measurement.

2. The method according to claim 1 , wherein said flow measurement device is a thermal anemometer.

3. The method according to claim 2 , wherein said thermal anemometer is a hot-wire anemometer.

4. The method according to claim 3 , wherein the applied fountain solution in an airborne state forms a fixed image area on the reimageable surface.

5. The method according to claim 4 , the method further comprising:
determining density of the air flow during the baseline measurement and the operational measurement.

6. The method according to claim 4 , the method further comprising:
determining a change in density due to the application of the fountain solution in an airborne state on the reimageable surface.

7. The method according to claim 6 , the method further comprising:
determining volume of the applied fountain solution on the reimageable surface from the change in density.

8. The method according to claim 6 , the method further comprising:
determining fountain solution thickness of the applied fountain solution from the determined volume and the fixed image area.

9. The method in accordance to claim 8 , the method further comprising:
controlling an optical patterning subsystem based on the determined fountain solution thickness of the applied fountain solution.

10. The method in accordance to claim 8 , the method further comprising:
controlling a fountain solution deposition process at the dampening station based on the determined fountain solution thickness.

11. An apparatus useful in printing with a variable data lithographic system having a reimageable surface, comprising:
a flow control structure that confines airborne fountain solution provided from a flow conduit to a condensation region to support forming a fountain solution layer at the reimageable surface;
an optical patterning subsystem being configured to irradiate the fountain solution layer according to digital image data;
a flow measurement device in line with said flow control structure which measures air flow around the reimageable surface;
a processor; and
a storage device coupled to the processor, wherein the storage device comprises instructions which, when executed by the processor, cause the processor to control optical patterning subsystem based fountain solution layer thickness by:
performing an assessment check, including taking a base line measurement of the air flow, and storing said base line measurement in a memory;
taking an operational measurement of the air flow with the flow measurement device during application of the fountain solution in an airborne state to the reimageable surface;
determining fountain solution thickness at the reimageable surface from a difference between the operational measurement and the base line measurement.

12. The apparatus according to claim 11 , wherein said flow measurement device is a thermal anemometer.

13. The apparatus according to claim 12 , wherein said thermal anemometer is a hot-wire anemometer.

14. The apparatus according to claim 13 , wherein the applied fountain solution in an airborne state forms a fixed image area on the reimageable surface.

15. The apparatus according to claim 14 , the apparatus further comprising:
determining density of the air flow during the baseline measurement and the operational measurement.

16. The apparatus according to claim 14 , the processor further performing:
determining a change in density due to the application of the fountain solution in an airborne state on the reimageable surface.

17. The apparatus according to claim 16 , the processor further performing:
determining volume of the applied fountain solution on the reimageable surface from the change in density.

18. The apparatus according to claim 16 , the processor further performing:
determining fountain solution thickness of the applied fountain solution from the determined volume and the fixed image area.

19. The apparatus in accordance to claim 18 , the apparatus further comprising:
controlling the optical patterning subsystem based on the determined fountain solution thickness of the applied fountain solution.

20. The apparatus in accordance to claim 18 , the apparatus further comprising:
controlling a fountain solution deposition process at the flow control structure based on the determined fountain solution thickness.

Assignees

• Xerox Corp

Inventors

• Mieney Christopher
• Vankouwenberg David A
• Frachioni Martin L
• Gurak David M
• Schweid Stuart A

Classifications

• G01B13/06

  for measuring thickness · CPC title

• G01P5/12 Primary

  using variation of resistance of a heated conductor · CPC title

• G03F7/20 Primary

  Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00) · CPC title

• G01P5/10

  by measuring thermal variables · CPC title