Why the unwinding web is wrinkled?

A: If the web is wrinkled in the unwinding part, the possible cuases would be as follows:
a. The web is originally wrinkled. No need to take any action in this case. The web would be pressed evenly later on. Or, the original wrikle can' t at all be removed. The master roll need to be replaced.
b. The wrinkle is caused by uneven pressure of the unwinding roller. Need to adjust the roller pressure by the handwheel manually or on the touch screen.