Summary

While the circumferential register in newspaper presses can be controlled with the use of electronic register controls (see IFRA Special Report 3.23), the application of such devices is possible only to a limited extent on the crosswise direction. Even when electronic sidelay register controls are offered to the industry and are partly used, we have to keep in mind that these are able to control only a single trace of the cylinder, but not the hydro-expension of the web caused by damping application and commonly called the fan-out effect. To compensate this fan-out effect so called anti fan-out rollers, also called "buzzle wheels", have been developed by varies suppliers, but their efficiency has been debated for many years. To clarify the situation IFRA commissioned the Swedish Newsprint Research Centre (TFL) in Djursholm, Sweden, with a research project on this. The study, carried out in a 400 mm wide pilot plant, demonstrated that the width of the web can be controlled by this means within appr. 20 urn which corresponds to an accuracy of the order of 0.05% of the 400 mm web. The control range for newsprint produced from virgin fibres has been found to be in the interval from 0 to 0.34%~ while that for newsprint produced from recycled fibres is in the range of 0-0.27%~. With the aid of prepositioning the plates this is more than enough to compensate the fan-out effect in daily practice. We hope that this report will promote the use of anti fan-out rollers and will inspire our supplier members to take actions along these lines for further developments, esp. on contactless devices like Mitsubishi’s Air Guns.