A roller consisting of a metal core (1) and a soft elastomeric coating (2) and two rigid necks (3, 3′) has between said metal core (1) and said elastomeric coating (2) a rigid conical layer (4) of a rigid elastomer permanently bound to the metal core, and a rigid, conical, slightly expandable support (5) which is permanently bound to the soft elastomeric layer (2), wherein a space allowing a lateral displacement of the support on the rigid elastomeric layer (4) can be generated between the rigid elastomeric layer (4) and the support (5) by compressed air flowing through. During the blowing through of air, an air cushion forms which allows to laterally displace and position the sleeve on the metal core. After the blowing of the air is stopped, the sleeve contracts and tightly embraces the conical rigid elastomeric layer (4).