Patent ID: 7235157

Claim:
A method for controlling at least one surface quality variable in a fiber web in a shoe calender having at least one calender nip, comprising the steps of: (a) providing a shoe element in each calendar nip; and (b) controlling, in each calender nip of the shoe calender, overall loading pressure of the shoe element and loading pressure difference between a leading edge and a trailing edge of the shoe element to achieve minimum difference between each determined value for the at least one surface quality variable of the fiber web and each set value for the at least one surface quality variable after the shoe calender, the controlling step being conducted based on the effect of the loading pressure difference between the leading edge and the trailing edge of the shoe element on the at least one surface quality variable as known through a control algorithm chosen from the group consisting of a response model, a table and a curve, whereby, when web rate V is substantially changed from a first fiber web rate V 1 to a second fiber web rate V 2 , controlling is carried out by changing mentioned set value for at least one surface quality variable in a staggered way over consecutive set values based on predicting control algorithm.