摘要 |
<p>A coater head (22) has a housing (23) which defines a coating pond (28) supplied with coating under pressure. A plurality of bars (21) extend within the coating pond (28) in the cross-machine direction, and are spaced parallel to one another in the machine direction. A paper web (36) is engaged against a backing roll (24), and travels through the coating pond (28) past a metering blade (30) which applies coating from the pond to the web. The bars (21) induce a turbulent flow which shears bubbles of air entrained in the coating pond, thereby reducing the bubble diameters and air-induced imperfections in the coating. Greater machine speed, which tends to entrain more air, induces greater shear at the bars which causes bubble size to be more greatly reduced.</p> |