Finishing Related

I recently completed a duplexing job for a client, they wanted 130 lb cougar sheets that where printed on a digital press, pasted together. Glueing went fine, used super 77 since it was a small amount.

We get to cutting, everything cut down fine until I flipped them over to inspect, the toner chipped of the backside of every edge of every piece.

The front and back where solid black, everything was cut from the back side of the blade.

Would die cutting possibly be the answer in the future? Just looking for some input.


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Lock up one knife and diecut thru one sheet, that should answer your question

I manage a modern printshop as my day job so I have a lot of experience with these kinds of problems. I can give you a few suggestions, but no panacea solutions.

Cracking around cuts is a really common issue with heavy coverage toner prints. The toner is basically a thermoplastic that is bonded to the surface of the paper by heat. Once it cools to room temperature it can wind up pretty brittle. When you cut the paper, the paper is compressed somewhat by the pressure of the clamp and the knife. Sometimes the paper can compress more than the toner can flex and so you wind up with cracking.

Die cutting might help some just because you’re cutting a single sheet at a time instead of a stack but I doubt it will totally alleviate the problem. Another option would be to try guillotine cutting in very short stacks (5 or 10 sheets) with several pieces of chipboard above and below to help even out the pressure. But if the stock is cracking now, you’re always likely to see at least some of it no matter how it’s cut.

You might see if your customer has a different make of printer they can try printing the cards on. Each manufacturer has their own proprietary formulations of toner and they all adhere to different papers in different ways. You may get bad cracking with (for example) prints from a Xerox Phaser, but none at all on the same stock off a Ricoh Pro.

Finally, you might also see if they’re willing to use the Cougar Super Smooth Cover if they aren’t already. It’s more heavily calendered so it’s slightly more compressed than the plain Cougar Cover. The plain Cougar 130# is about 17.5 pts thick, whereas the Cougar Super Smooth 130# is about 16.3 pts. That extra calendering may keep the paper from compressing so badly during the cut.

Michael Hurley
Titivilus Press
Memphis, TN