Web lifter/stabilizer and method
Web lifter and/or stabilizer and method of lifting and/or stabilizing a travelling web and for coating a web. The device creates a web hold down force via a negative pressure slot at its exit side, which draws the web down against the surface on the entry side. The device can be actuated to move the web relative to a slot die coater off the die lips and stop the application of slurry to the web, thereby creating uncoated regions on the web surface. The device can then be actuated to move the web back into contact with the coater to start the application of slurry to the web, thereby creating coated regions on the web surface. Web lifting can be accomplished by rotating the device in first and second directions to lift the web off of the slot die coater and return the web back into contact with the coater.
1. A method of applying a coating to a web using a system comprising a supply valve, a bypass valve, a free span slot die coater having die lips, a web lifter and a controller to control said supply valve, said bypass valve and said free span slot die coater, said method comprising:
inputting to said controller the reference positions on said web where said supply valve is to open and close;
inputting to said controller the reference positions on said web where said bypass valve is to open and close;
inputting to said controller the reference positions on said web where said web lifter is to be actuated to move said web toward and way from said free span slot die coater;
moving said web past said free span slot die coater;
tracking the position of said web; and
using said controller to control said supply valve, said bypass valve, said free span slot die coater and said web lifter based on said inputted reference positions to lift said web off said die lips of said free span slot die coater and stop the application of coating to said web to create uncoated regions on said web, and to move said web into contact with said die lips of said free span slot die coater and initiate the application of coating to said web to deposit said coating on said web to create coated regions on said web.
2. The method of claim 1 , wherein said controller comprises memory storage to store reference position data for said web.
3. The method of claim 2 , wherein said reference position data comprises positions of said web where said supply valve is to open and close.
4. The method of claim 2 , wherein said reference position data comprises positions of said web where said bypass valve is to open and close.
5. The method of claim 2 , wherein said reference position data comprises positions of said web where said web lifter is to be actuated to deflect said web.
6. The method of claim 1 , further comprising sensing the position of said web and communicating the sensed position to said controller.
7. The method of claim 1 , wherein said web lifter is positioned upstream of said free span slot die coater in the direction of travel of said web.
8. The method of claim 1 , wherein said web is a conductive substrate.
9. The method of claim 1 , wherein said actuation of said web lifter rotates said web lifter.
10. The method of claim 1 , wherein said controller controls the opening and closing of said bypass valve and the speed at which said bypass valve is opened and closed.
11. The method of claim 1 , wherein said controller controls the opening and closing of said supply valve and the speed at which said supply valve is opened and closed.
12. The method of claim 1 , wherein said web lifter has a body having a first portion defining a leading edge of said body, and a second portion defining a trailing edge of said body, said first portion being spaced from said second portion so as to define an air entry slot between them for the entry of air upon application of negative pressure to said body.
13. The method of claim 12 , further comprising applying negative pressure to said air entry slot.