Calender for the treatment of web-like materials, including a fixed structure supporting two heated rollers reciprocally arranged so as to form a nip traversable by web-like materials, where each roller has pins mounted on bearings. The structure includes two lower levers and two upper levers adapted for exerting on the bearings forces oriented according to not coinciding directions, each lever being connected with an actuator that controls its rotation around a horizontal axis to put it in a first engagement position of the respective bearing and in a second release position, such that in the second position of the levers the extraction of the rollers from the calender is allowed.

The manufacturing apparatus of the present invention comprises a die for extruding a resin plate and a first roller and a second roller for molding the resin plate. The manufacturing apparatus further comprises: an inner deckel for dividing the resin plate and pre-forming a thick section; and a main molding section provided on the first roller and/or the second roller for molding a non-uniform thickness section from the thick section.

An extruding unit, a forming roll unit and a thick portion forming mechanism are provided. The extruding unit has an ejecting slit which ejects sheet-shaped molten resin. The ejecting slit includes a standard gap portion and an enlarged gap portion. The standard gap portion is formed as a gap having a constant size. The enlarged gap portion is formed as a gap larger than the standard gap portion in a position corresponding to a thick portion. The thick portion forming mechanism forms one or several thick portions which are thicker than other portion, in the sheet-shaped molten resin continuously in the extrusion direction.

The manufacturing apparatus of the present invention comprises a die for extruding a resin plate and a first roller and a second roller for molding the resin plate. The manufacturing apparatus further comprises: an inner deckel for dividing the resin plate and pre-forming a thick section; and a main molding section provided on the first roller and/or the second roller for molding a non-uniform thickness section from the thick section.