To correctly operate a belt, and improve the durability of the belt by eliminating fluctuation even the fluctuation begins to be caused in the feed per revolution of the belt due to the slips between a pulley and the belt.
An endless belt 15 is wound on driving and driven pulleys 13 and 14, and is provided with marks 21 at given intervals in the moving direction of the belt 15. The pulley 13 is intermittently driven at strokes in accordance with the intervals P of marks 22 so as to stop the marks 21 in order at a measuring place S, to measure a distance between the marks 21 stopped at the place S by the sensor 22 and the sensor 22. The deviation, between a reference distance set beforehand and a measured diatance, is determined, to make a set value in accordance with the determined deviation as a belt movement stroke based on the corresponding relation between preset diviation and a set value.
NISHIO YOJI
FUJIKAWA KOJI
UEDA MICHIO
