A Feed-forward Tension Control in Drying section of Roll to Roll e-Printing Systems

The mathematical model for tension behaviors of a moving web by Shin (Shin, 2000) is extended to the tension model considering the thermal strain due to temperature variation in a dryer of the roll to roll systems. The extended model includes the terms that take into account the effect of the change of the Young’s Modulus, the thermal coefficient, and the thermal strain on the variation of tension. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of web could be compensated by using the velocity adjustment. The computer simulation and experimental validation was carried out to confirm the performance of the proposed tension control method. The results show that the suggested tension control logic improves the performance of tension control in a dryer section of the roll to roll systems. NOMENCLATURE A : Cross-sectional area of web E : Young’s modulus L : Length of span T : Change in the web tension from a steady-state operating value t : Tension of web V : Change in the web velocity from a steady-state operating value v : Velocity of roller α : Thermal coefficient β : Velocity difference ε : Strain of web th ε : Thermal strain e ε : Elastic strain θ : Temperature ρ : Density of web SUBSCRIPT eq : Equivalent N : Index op : Steady-state operating value