In the printing industry, what is a three-sided cutter?

When operating the paper cutter, when the "cut" button of the paper cutter is pressed, if the blade runs abnormally for more than two consecutive times, this is what the printing industry usually calls "cutting". The resulting defective page is a flat cut page.

Even the knife is probably caused by the failure of the limit switch of the cutting knife or the failure to touch the limit switch, and the adhesion or lag of the relay contact.

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