Heated pressure rolls

Pressure roll apparatus comprising a cylindrical core of material having a plurality of axial slots in side-by-side relationship, said axial slots being alternately bordered by an array of cavities having a depth substantially less than that of said axial slots, a tubular sleeve over said core having an inside diameter which is less than the outside diameter of said core at ambient temperature and greater than the outside diameter of said core at cryogenic temperatures, and a heating element disposed in said slots of said core.

Apparatus for providing a permanent image on a sheet by fixing an image of toner material which is obtained from an electrostatic latent image by depositing toner material upon said sheet to provide such toner material image in conformity with said latent image, said apparatus comprising at least one pressure roll comprising a sleeve component and a core component, said core component having a general circular configuration with an array of axial slots comprising circular sectors, said axial slots being alternately bordered by an array of cavities having a depth substantially less than that of said axial slots, and a heating element disposed in said slots.

Apparatus for providing a permanent image on a sheet by fixing an image of toner material thereto, said apparatus comprising at least one pressure roll comprising a sleeve component and a core component, said core component having a general circular configuration with an array of axial slots comprising circular sectors, said axial slots being alternately bordered by an array of cavities having a depth substantially less than that of said axial slots, a heating element disposed in said slots, and a hydrostatic assembly for establishing a contact pressure between said pressure roll and said sheet.