Heated roller with integral heat pipe

A heatable transfer roller usable in a machine for coating, printing, copying or web heating, the roller comprising:

• a roller core of a thermally conductive material, the roller core having an inner hollow cavity and an outer wall around the inner cavity;
• a sleeve of a thermally conductive material disposed on the roller core for conducting heat with respect to an object contacting an outer surface of the roller;
• wherein the roller core and the sleeve form a ring-shaped cavity for receiving a heat transfer medium, the ring-shaped cavity extending the length of the roller excluding portions on respective ends of the roller and said cavity having an inner interior surface and an outer interior surface relative to the roller core;
• means for transfer of heat in relation to the heat transfer medium in the ring-shaped cavity;
• flow restriction elements disposed around the circumference of the roller core and within said cylindrical cavity to form compartments;
• a wicking material for wicking the heat transfer medium, said flow restriction elements tending to retain the wicking material and the heat transfer medium inside of said compartments, while also allowing the heat transfer medium to move circumferentially around the roller to make temperature more consistent across the outer surface of the roller;
• and
• wherein the flow restriction elements are formed by the wicking material, which further comprises a wire screen with transverse folds, the wire screen extending circumferentially in said cavity, and wherein said transverse folds extend across the cavity from near the inner interior surface to near the outer interior surface.