1. Field of the Invention
The present invention relates to the application of a coating medium by use of a spray device onto a moving surface, whereby in the direct application method the moving surface is the surface of a material web, specifically a paper or cardboard web, and in the indirect application method is the surface of a transfer element from which the coating medium is transferred to the material web.
2. Description of the Related Art
Devices for application of a coating medium by use of a spray device onto a moving surface are already known from EP 0 670 004 B1, WO 94/11116 and EP 0 435 904 B1. Generally, the objective of this type of spray applicator device is to apply the coating medium with as little excess as possible, and in the best case scenario even with no excess at all (1:1 application) to the moving surface. In the application methods described in the above referenced publications, the coating medium is atomized by use of air and is applied to the moving surface. After the coating medium has settled there, the carrier air is suction removed from the application area through channels surrounding the spray apparatus. Even with very low application base weights, very large volumes of air must be supplied to and suction removed from the moving surface in a given time period. It has been demonstrated in practice that, from a quality point: of view, only an insufficiently satisfactory coating result can be achieved with the previously known coating methods. Despite subsequent smoothing of the applied layer, the layer still displays an uneven structure as well as a rough, sandpaper-like a surface.
USPTO Backgrounds
USPTO Backgrounds