Device and method for treating substrates using a platen roller with a porous material

An apparatus for treating substrates with a treatment fluid has at least a rotatably mounted support roller on which rests a substrate to be treated during operation. The roller platen has a hollow cylinder having a porous rigid material that rests on the substrate to be treated during operation. The apparatus is designed to via the interior of the hollow cylinder at least to promote the operation of the treatment liquid of a platen roller through the porous rigid material on the outer surface of the hollow cylinder, at least to treat a surface of the substrate with the treatment liquid