Fecha de publicación: -- Fuente: WIPO "tomato" There is described a packaging machine (1) comprising a conveying device for advancing a web (4) of packaging material; a web folding device (5) including a plurality of folding rollers (6) configured to fold the web (4) into a tube (3) by superimposing a first longitudinal edge (4a) of the web (4) onto a second longitudinal edge (4b) of the web (4) thereby defining a superimposing region (50) of the tube (3); a heating device (13) configured to heat the tube (3); a presser roller (14) located inside the tube (3) and configured to press the superimposing region (50) against one folding roller (6) for providing the tube (3) with a longitudinal seal (11); a resting member (16) located inside the tube (3) and configured to receive in abutment said folding roller (6) with the interposition of the packaging material of the tube (3), so that, in use, the packaging material is pressed between said folding roller (6) and the resting member (16)