Patent ID: 7017493

Claim:
In an offset printing machine having at least one printing unit in which a printing substance is applied to sheets and the printed sheets are directed through the printing machine comprising an apparatus for treating surfaces of the printed sheets, said surface treating apparatus including a first roller ( 2 , 7 ) rotatable in a first direction and having a placement surface for sheets during travel through said machine, a second roller, ( 4 , 5 , 6 ) mounted in axially parallel relation to said first roller ( 2 , 7 ) for defining a roller nip with said first roller ( 2 , 7 ) through which printed sheets are directed, said second roller ( 4 , 5 , 6 ) being mounted with a preset radial force in the range of 10–25 N/cm against said first roller ( 2 , 7 ) at said nip, said second roller ( 4 , 5 , 6 ) having a diameter smaller than the diameter of said first roller ( 2 , 7 ) and being rotatable in a direction opposite to the direction of rotation of said first roller ( 2 , 7 ), and a heating device ( 11 , 12 , 15 , 16 ) operatively associated with said second roller ( 4 , 5 , 6 ) for heating the surface of the second roller in the region of the roller nip between said first roller ( 2 , 7 ) and the second roller ( 4 , 5 , 6 ) to a temperature of at least about 350° K as the sheet passes through the nip whereby the heat and pressure on the printed sheet smoothes the surface of the printing substance on the printed sheet passing through the nip.