An apparatus and method for applying reference or grid markings to wallboard during the manufacturing process is disclosed. Reference or grid markings are applied to one sheet of cover paper at a location between the originating cover paper rolls and the cover paper creaser or creasers. This is accomplished...http://www.google.es/patents/US7151553?utm_source=gb-gplus-sharePatente US7151553 - Apparatus for applying reference markings to wallboard during manufacture
Apparatus for applying reference markings to wallboard during manufacture
