A method for prepressing an assembly of stacked, superimposed glass and plastic sheets for subsequent autoclave lamination to provide a glazing. The apparatus includes a frame positioned between a delivery conveyor and a discharge conveyor and carrying prepress and support rollers. An assembly arrives on the delivery conveyor and is aligned and rotated ninety degrees before entry into the frame. The prepress rollers are rotatably mounted in pairs and attached to air cylinders which retract the rollers during entry to clear a vacuum ring which extends about the peripheral edge of the assembly such that a vacuum can be drawn on the assembly during the application of pressure and then extend the rollers into contact with an upper surface of the assembly to apply pressure thereto. The assembly is supported from its bottom side by the support rollers which are rotatably attached to the frame are located on either side of a plurality of drive rollers which are rotatably attached to the frame in pairs. The drive rollers are of different diameters and are adjustably mounted on an axis of rotation which is tilted from the horizontal path of the assembly. The drive rollers are driven to move the assembly through the frame while the prepress rollers apply pressure to the assembly. The different diameters and the tilted axis of rotation compensate for different lengths of the paths of travel of the drive rollers along the surface of assemblies of curved or bent sheets.