Abstract: A process and an apparatus for the manufacture of SC-A paper having a high gloss and high smoothness, wherein the paper arriving from the paper machine is supplied on-line to a supercalender (multinip soft calendar), and wherein the paper travels through a plurality of nips for achieving the desired gloss and smoothness properties. The paper web arriving from the paper machine and supplied on-line to a supercalender (multinip soft calendar) is moistened with steam immediately prior to the first nip of the supercalender and is guided through the first nip before the increased moisture of the surface resulting from the application of steam has dropped below a predetermined value in the range of 12% to 25%.

Abstract: A gloss control system especially for use on a super calender roll system uses controllable jets of heated air arranged along the segment of a calender roll not in contact with a paper web to both control the overall gloss level and equalize the expansion and contraction of the roll which would otherwise be affected by the heat sink effect of the paper on the contacted portion of the roll causing an hour-glass effect. The air jet units utilize electrical heating elements and are actually arranged along, for example, 11/2 inch zones of the paper to provide for a differential profile control with relatively cold air on the uncovered ends of the calender roll to compensate for contraction of the center portion of the roll.

Abstract: A throttle valve is provided in each actuator of a calender roll controller with the throttle valve controlling an internal air orifice within each actuator to provide a substantially uniform air mass flow of either hot or cold air. Each throttle valve is controlled in response to the temperature of the air being delivered by the actuator such that a smaller orifice is provided for hot air than for cold air to provide substantially uniform air mass flow from each of the actuators and therefore substantially uniform air velocity to better control the temperatures of the longitudinal zones of a calender roll and better maintain boundaries between the zones. In addition to throttle valve control of the actuators, an air scoop concentric with a calender roll being controlled and spaced from the calender roll is provided to channel air from the actuators over the calender roll. The scoop comprises heat insulating material to prevent heat loss out the back of the scoop.

Abstract: A paper calendering apparatus comprises a nip section for advancing paper sheets formed by at least a pair of rollers, one of which is a metal roller and the other of which is a resilient roller or a metal roller, wherein a gap of equal spacing is formed along the entire width of the roller face at the nip section of the pair of rollers, and is set to less than the thickness of the paper sheet to be finished.