Method and application group for applying a fluid onto a substrate
AssigneeCanon Production Printing Holding B.V.
InventorManfred Viechter
Life of this patent
Estimating the term…
Abstract
A fluid for application onto a substrate is provided in a cavity of a hollow cylindrical application roller that has porous roller wall. Before reaching the transfer point to the substrate, fluid is regionally selectively pushed back away from the outer shell surface of the application roller, into the porous roller wall, by a knockback pressure, in order to regionally selectively produce the effect that, at the transfer point, fluid is located at the outer shell surface of the application roller or no fluid is located at the outer shell surface of the application roller. A regionally selective application of fluid onto a substrate may thus be efficiently produced.
Claims12
An application group for applying a fluid onto a substrate, the application group comprising:
- a hollow cylindrical application roller having a porous roller wall and a cavity, the fluid to be applied onto the substrate being located in the cavity, wherein the fluid moves with an extrusion speed through the roller wall to an outer shell surface of the application roller due to an internal pressure of the application roller;
- a drive configured to rotate the application roller with a rotation speed in a rotation direction;
- and
- a knockback pressure generator arranged before a transport point to the substrate, in the rotation direction, and configured to generate a knockback pressure to regionally selectively push a portion of the fluid away from the outer shell surface of the application roller and towards the cavity of the application roller, wherein the extrusion speed, the rotation speed, and the knockback pressure are matched to one another such that:
- in a first region of the outer shell surface of the application roller in which the knockback pressure has been produced by the knockback pressure generator, minimal or no fluid is located on the outer shell surface of the application roller when the first region reaches the transfer point;
- and
- in a second region of the outer shell surface of the application roller in which the knockback pressure has not been produced, fluid is located on the outer shell surface of the application roller when the second region reaches the transfer point.
A method for applying a fluid onto a substrate, the method comprising:
- producing an effect to cause fluid to move with an extrusion speed from a cavity of an application roller, through a porous roller wall, to an outer shell surface of the application roller;
- rotating the application roller with a rotation speed in a rotation direction;
- and
- selectively generating a knockback pressure at a knockback point on the outer shell surface of the rotating application roller, the knockback point being arranged before a transfer point to the substrate in the rotation direction to regionally selectively push a portion of the fluid away from the outer shell surface of the application roller and towards the cavity of the application roller, wherein the extrusion speed, the rotation speed, and the knockback pressure are matched to one another such that:
- in a first region of the outer shell surface of the application roller in which the knockback pressure has been produced by the knockback pressure generator, minimal or no fluid is located on the outer shell surface of the application roller when the first region reaches the transfer point;
- and
- in a second region of the outer shell surface of the application roller in which the knockback pressure has not been produced, fluid is located on the outer shell surface of the application roller when the second region reaches the transfer point.
Dependencies are inferred from the claim text.