What is it a protruding or slipped core?
A protruding or slipped core is when the core of the wound paper sticks out beyond the width of the paper roll. This defect concerns web offset printers or any other printing application that uses rolls.
What causes a slipped core?
If a core is sticking out the side, it is probably caused by a slack start when the paper is made at the paper mill. Fore more detail on how paper is made, go here. When a new reel is started, tension must be absolutely tight. This can be a challenge when getting the reel started. Below shows a picture of the result if the tension is not tight.
Occasionally this will cause the core to slide. It can occur at the paper mill or later when the roll is loaded onto the press.
Other causes of a protruding core
Sometimes this is not due to a slack start, but to the fact that the roll was made at the end of a reel at the paper mill. The core was simply a little too long for the entire reel. In this case, the roll should not cause any problem as long as the roll stand shaft will line up properly. (See below)
But a problem can occur when the last roll of a paper reel has the core, not protruding, but slightly inside the roll. This causes the paper to buckle around the core.
What do do about it
It is recommended to splice off the roll early. This is clearly a fault of the paper mill and the weight of the paper can be claimed against it.
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