Tension controller for controlling tension of running paper web

A tension controller for controlling the tension of running paper web in a rotary press which includes a tension control unit for controlling an infeed roller unit arranged along a paper web path which extends between a paper web feed unit and a printing unit, the paper web feed unit being loaded with a paper roll which is rotatably supported by a support unit having a brake, the printing unit comprising a printing cylinder, the paper web being drawn out from the paper web feed unit by the infeed roller unit, and the infeed roller unit including an infeed roller, an infeed roller drive source which commonly serves as a printing cylinder drive source, an infeed roller drive transmission connected to the infeed roller drive source and used for changing the peripheral speed of the infeed roller, infeed roller drive transmission regulation means for regulating the speed change ratio of the infeed roller drive transmission in accordance with a speed change ratio regulation signal received from the tension control unit, and a peripheral speed ratio detection unit which detects the peripheral speed ratio of the infeed roller to the printing cylinder determined by the speed change ratio of the infeed roller drive transmission and which is connected to the tension control unit so as to input a signal representing the detected peripheral speed ratio to the tension control unit,

• said tension controller comprising an floating roller unit disposed upstream of the infeed roller and a dancer roller unit disposed downstream of the infeed roller, and said tension control unit controlling the infeed roller drive transmission regulation means and the dancer roller unit, wherein
• said floating roller unit comprises a floating roller around which paper web is looped and which can move so as to increase and decrease the length of the paper web path between the paper web feed unit and the infeed roller, a fluid cylinder for displacing the floating roller so as to increase the length of the paper web path against the tension of the running paper web, and a fluid pressure detection unit for detecting the pressure of a fluid fed to the fluid cylinder;
• said dancer roller unit comprises a dancer roller around which paper web is looped and which can move so as to increase and decrease the length of the paper web path between the infeed roller and the printing unit, a fluid cylinder for displacing the dancer roller so as to increase the length of the paper web path against the tension of the running paper web, a fluid pressure change unit for changing the pressure of fluid fed to the fluid cylinder of the dancer roller, dancer roller positioning means for stationarily maintaining the dancer roller at a predetermined position, dancer roller displacement direction detection means for detecting the displacement direction of the dancer roller, dancer roller displacement speed detection means for detecting the displacement speed of the dancer roller, and dancer roller displacement position detection means for detecting the displacement position of the dancer roller;
• and
• said tension control unit is adapted to receive a peripheral speed ratio detection signal from the peripheral speed ratio detection unit of the infeed roller unit, a fluid pressure detection signal from the fluid pressure detection unit of the floating roller unit, and signals related to rotary press operation such as a minimum speed operation signal, a minimum speed signal, an acceleration signal, an impression on signal, a stop signal, a sudden stop signal, an impression off signal, and a paper break signal, based on these detection signals, said tension control unit inputting a speed change ratio regulation signal to the infeed roller drive transmission regulation means so as to control the peripheral speed ratio of the infeed roller to the printing cylinder and inputting clamp and release signals into the dancer roller positioning means, as well as inputting a fluid pressure change signal into the fluid pressure change unit of the dancer roller unit.