Folded filter paper produced by grooving rolls - fed with paper under slight thrust to compensate variations

摘要

In making folded filter sheets, esp. folded paper strip, the strip is clamped between the grooving (creasing) rolls then a portion of strip on the feed side of these rolls is subjected to a pushing stress, which is released after the strip has been grooved. The variations in action caused by irregularities and unevenness of the paper are removed and uniform folding results. By varying the feed speed on the feed side of the grooving rolls, folds of different heights can be produced.