Web Tension Research on Rotogravure Presses.

Full width or unit type tensiometers may be used for dynamic measurement of web tension on rotogravure or other web fed presses. Calibration and interpretation of quantitative results obtained with tensiometers measuring unit tension in lbs./inch directly must consider the effects of calibrating web widths, hysteresis or memory effect of paper under repeated stressing and the effect of moisture content on paper elastic properties among other things. Qualitative tension measurements made with unit tensiometers on rotogravure presses show that variation in tension setting at the reel influences web tension at all press units including those past the first impression. Tension variations exist during normal press operation of both low and high frequency natures and extreme tension disturbance occurs during paster cycles. These and other tension disturbances pass through the press in the direction of web travel and are definitely correlated with color misregister. More research is needed for a better understanding of these phenomena and to achieve the desired improvement in web press performance.