Abstract
The rubber surface of a size press roll of a paper making machine is deformed into a certain convex polygon at a high nipforce and at an operating speed. This problem is similar to other pattern formation phenomena, for instance, polygonal deformations of the smoother roll in paper making machine, regenerative chatters in cutting, and the polygonal deformation of the work roll in a hot leveler. In the size press part, the surface of the paper is coated with starch between the rubber rolls. As the operating speed increases, the pattern formation phenomena are likely to occur. This paper describes the countermeasures to avoid the pattern formation by changing the diameter ratio of the top to the bottom roll. It is found from the numerical analysis that the optimum ratio exists to decrease the instability effectively.
