Patent ID: 6854496

Claim:
A double facer for use in a corrugated fiberboard sheet manufacturing system which conveys a single faced corrugated fiberboard sheet and a linerboard in a state where they are placed in a superposed condition, put between heating means and pressing means, and heated and bonded at the same time forming a double faced corrugated fiberboard sheet, said double facer comprising: moisture content detecting means for detecting moisture content or a parameter correlating with the moisture content of said double faced corrugated fiberboard sheet after said sheet is passed through said heating means; control means for controlling a heat reception quantity of said double faced corrugated fiberboard sheet on the basis of a detection result from said moisture content detecting means so that the moisture content of said double faced corrugated fiberboard sheet approaches a predetermined optimum moisture content, said control means including a decision means for making a decision as to whether or not a deviation between the optimum moisture content and a moisture content detected by said moisture content detecting means is below a predetermined value, said control means further including: a feedback control element for implementing the heat reception quantity control through the use of feedback control when said decision means makes the decision that said deviation is below a predetermined value; and a feedforward control element for implementing the heat reception quantity control through the use of feedforward control when said decision means makes the decision that said deviation is equal to or more than said predetermined value.