The influence of fibre shives on calender cuts in newsprint

Latewood shives act as sheet-rupture-inducing weak spots in hard-nip calend ered TMP-based newsprint paper. The latewood shives mise local grammage ove r ct critical level where all voids are completely compressed in the calend er nip. This high degree of compression cuts and damages the fibre material close to the shive and makes it act like a short cut in the paper: About 9 0% of the total amount of shives in the newsprint were found to consist of earlywood fibres, however these shives did nor seem to act as sheet rupture inducing weak spots in the same manner as did the latewood shives.