ok so the subject says it all. i’m printing 1mm thick cardboard and the gripper arm leaves marks on the stock… is there an adjustment to relieve the gripper pressure, grabing the paper?
this happens in a non-linear manner—happens on thinner stocks and randomly… also, sometimes, one of the grippers kisses the front guard sounding a “pimm!”
i need help relating to this problem… thanks once again!
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There’s no adjustment that I’m aware of but either the packing is too heavy or it is possible the gripper is bent. Is there anything in the chase that could be pushing against the gripper?
Is the mark on the grip edge ,about 2inch or so from the lay edge ?
it is on the grippers axis side. but I guess you’re right peter on your last response to the other thread. I guess that I’m demanding too much from this beast…
Can you get over sized stock? treat job like a bleed, trim off marked edge. Keep it simple.
assuming there is nothing else wrong with your press, here is what I think is happening: The paper being .040” is so thick that when the impression is made the gripper is hitting the chase with enough pressure to mark the cardstock.
I have had the same problem trying to print .050” coasters.
Running oversize and trimming would work.
Richrd T , has a good point but i believe its the level the gripper operates at is kinking the material as the impression is created , the gripper is holding it with a downward pressure against the packing .The gripper is not set for a beer mat board and a load of soft packing ,it is designed to print on the heavy board as used for beer mats and packing properly measured to give print evenness this would print without this trouble . However the extra packing used to gain the heavy impression is partly responsible for the marks described formerly .
There have been questions about this here before and thoughts of raising the gripper carrier from the platen will not solve it even if it were possible to do so , raising the cast gripper carrier will create sidelay problems .
I would suggest you have the typical 10mm trim on the gripper edge .
On a poorly set up machine the grippers can mark the edge at the feeding end of the operation , you can only find this properly by running sheets through with as little packing as possible and not printing .
Then again gripper twisted , stop the platen with the gripper angled across the platen ,get a small pocket steel rule that is straight put a piece of double side adhesive at the midway mark , slide rule under platen gripper about three inches from the tip , make to a 90o angle and get the tape beneath th gripper when positioned it will look like a cross for church hold the rule still and with you hand bang the gripper down on the rule and the rule will stick flat to the gripper . Look at the rule at either end and the ends should be an equal distance off the platen , not very scientific but effective . to release rule twist it round dont try lifting it off !