We had reported earlier (NIP 18) the use of high intensity continuous radiation and pulsed radiation for color independent radiant fusing. We had found that there is a potential if special developed sharp melting dry ink is used.At duplex fusing of sheet substrates with electrophotographic engines of duplex loop type the paper passes twice the fusing station with the risk of reheating the first image above softening point. We have analyzed different methods of paper feeding in the fusing area: With radiant fusing the heating time is relatively long with the risk of backside damage. Thus a non-contact paper feeding in the heating zone followed by a non contact paper feeding in the following cooling zone is required.At flash fusing the energy is incorporated into the surface for short time intervals only and backside problems are not expected. To prove this we evaluated the time dependant backside temperature of the substrate after flash fusing with a fast pyrometer. We could prove that backside image artifacts of toner back side layers in full color printing start well above the flash energy density necessary for fusing. Thus conventional contact paper transport means like Kapton® belts are sufficient for duplex color flash fusing of sheet materials.