| 摘要 |
A paper processing calender, esp. for producing gravure-printable paper, has a stack of rolls which are loaded from one end. A working nip is formed between each adjacent hard and soft roll pair, and a change-over nip is formed between two adjacent soft rolls. The rolls are at least partly heated, and at least one of the end rolls can be controllably flexed. The number of rolls (2,9) in the stack is limited to not more than eight, and in order to increase the energy for deformation of the paper, the residence time in at least one nip is at least 0.1 ms. The heating arrangement for a heated roll (2,4,7,9) is such that a surface temp. of at least 100 degrees C is maintained, and the roll loading is such that the pressure in the working nip is at least 42 N/mm<2>. Also claimed is a process for operating a calender in which the average temp., pressure, and residence time in the nip are such that the following equation is satisfied: 1.378-0.00356 x T x (0.00825-5.12x10<-5>xT) x p - Ä0.039+(0.188-0.00112T) x p x e<-0.093>Ü x t x e<-0.412>t =0.8 to 0.9. |
