A calender for the treatment of web-like materials, including a fixed structure adapted to support two heated rollers shaped to be connected to the fixed structure, to a drive unit and to a heating system. The calender includes automatic elements for engaging and respectively for disengaging the rollers to and from the fixed structure, the drive unit and the heating system; the automatic elements are controlled by a programmable control unit and each of the rollers has an engaging surface shaped to be engaged by mechanical elements for moving the rollers which move the rollers between the calender and one or more waiting or parking stations while the rollers are at a temperature between 50° C. and 200° C.