Fluid supply device for a printing machine

1. A fluid delivery device for a printing machine comprising:

a rotating roller having a roller surface with a roller radius of curvature, the roller surface carrying a fluid film; and

a metering element having an edge for splitting the fluid film and a first concave surface facing the roller surface;

the metering element being movable with respect to the roller surface so that the edge moves along a radial line from a center of the rotating roller.

2. The device as recited in claim 1 wherein the metering element has a second concave surface opposite the first concave surface.

3. The device as recited in claim 1 wherein the first concave surface has a radius of curvature similar to that of the roller radius of curvature.

4. The device as recited in claim 1 wherein the first concave surface corresponds to an arc of 10 degrees or more of the roller surface.

5. The device as recited in claim 1 wherein the metering element is rigid.

6. The device as recited in claim 1 wherein the metering element has a horizontal bottom surface.

7. The device as recited in claim 1 wherein the fluid is ink.

8. The device as recited in claim 1 wherein a thickness of the fluid film downstream from the metering element is half of an average distance of the concave surface from the roller surface.

9. The fluid delivery device as recited in claim 1 further comprising a reducer roll interacting with the rotating roller.

10. The fluid delivery device as recited in claim 1 further comprising a fluid supply container, the roller surface contacting the fluid supply container and the fluid film before splitting exiting the supply container.

11. A method for metering fluid in a printing press having an operating speed comprising the steps of:

supplying fluid to a supply container;

rotating a roller so as to form a film of the fluid on a surface of the roller; and

splitting the film using a metering element, the metering element having a concave surface facing the surface of the roller;

wherein metering element has an edge movable solely in a radial direction with respect to the roller.

12. The method as recited in claim 11 further comprising setting a distance between the concave surface and the surface of the roller.

13. The method as recited in claim 11 wherein the first concave surface has a radius of curvature similar to that of the roller radius of curvature.

14. A fluid delivery device for a printing machine comprising:

rotating roller having a roller surface with a roller radius of curvature, the roller surface carrying a fluid film; and

a metering element having an edge for splitting the fluid film and a first concave surface facing the roller surface;

the metering element being movable with respect to the roller surface;

wherein the metering element has a second concave surface opposite the first concave surface.

15. The device as recited in claim 14 wherein the metering element has an edge movable radially along a line from a radial center of the roller.