Abstract: An optical sheet forming technique includes an extrusion unit having a discharge slit, a forming roll unit having rolls rotatable about rotation axes, a thick portion forming groove provided in the forming roll unit, and a position adjustment mechanism which adjusts a position of a discharge slit with respect to the thick portion forming groove. In a discharged molten resin, a neck-in portion caused by a neck-in phenomenon is continuously formed in an extrusion direction. The neck-in portion is positioned to be opposed to the thick portion forming groove by the position adjustment mechanism.

Abstract: By provision of a plurality of rolling rubber rolls 70 each adapted for a sliding contact with an outer circumferential surface of a central rotational shaft 20 and a sliding contact with an inner circumferential surface of an outer tube 40, an annular space between the central rotational shaft 20 and the outer tube 40 is divided by the rolling rubber rolls 70 in the circumferential direction into a plurality of heat medium chambers 91, 92, 93, and 94, the plurality of heat medium chambers being each respectively configured for individual conduction of heat medium.

Abstract: By provision of a plurality of rolling rubber rolls 70 each adapted for a sliding contact with an outer circumferential surface of a central rotational shaft 20 and a sliding contact with an inner circumferential surface of an outer tube 40, an annular space between the central rotational shaft 20 and the outer tube 40 is divided by the rolling rubber rolls 70 in the circumferential direction into a plurality of heat medium chambers 91, 92, 93, and 94, the plurality of heat medium chambers being each respectively configured for individual conduction of heat medium.