Abstract: A device is provided for applying a fluid surface treatment agent to a paper web that includes a container for receiving the fluid surface treatment agent to be applied. The container includes a gap which is mounted for contact with the paper web for transferring the fluid from the container to the paper web. A rotary brush is positioned opposite the gap and on the other side of the paper web, and includes fluffy surfaces for applying pressure to the paper web to press the paper web into contact with the fluid applying gap. The position and pressure of the brush are adjustable, and a casing is provided to at least partially surround the brush to produce a fan effect on the paper web as the brush rotates relative thereto.