heat evolution in the foil after the ends of the strip 100 have melted they flow into one another and a weld forms which is amorphous this weld is treated in such a manner that the support material crystallizes at the location of the weld for this purpose an amorphous weld that has cooled in the meantime can be heated to a temperature at which the molecules in the foil are sufficiently mobile to re crystallize but not so mobile that the material again passes over to the melt typically a temperature is selected which is a few degrees below the melting temperature of the material heating of the weld to this temperature can be effected by irradiating the weld with laser light from the laser sources 50 and 51 referred to above in the manner described above it is thus possible to obtain an endless support suitable for forming an endless image forming medium in a particular embodiment of the present invention the ends of the initially amorphous weld i e those parts of the weld that coincide with the edges of the newly formed belt are not treated to become crystalline instead these ends remain amorphous it appears that in this way the local resistance against mechanical damage of the weld is increased significantly fig3 shows an endless support 100 obtained by the use of the welding.