A slack start is the cause of paper wrinkling near the beginning of the core of a paper roll. Web offset printers will usually splice off early to avoid these defect wrinkles. However these wrinkles can extend part way into the roll and results in distorted print or even web breaks.
How does this defect happen?
Paper machine companies begin a new roll called a jumbo when starting a new paper roll. These rolls rely and a tight start at the core. When this doesn't happen, the first few winds can have wrinkles.
 |
| Paper roll jumbo on paper machine. |
Paper manufacturers will make some kind of disclaimer that their rolls are usable only at a certain distance from the core. If this paper defect goes beyond this, a complaint or even a claim can be made by the offset printer against the paper company. To be safe, it is best to establish a buffer amount and to splice off slightly early on each roll.
thanks for sharing this
ReplyDelete