Windmill gripper tearing packing when stopped at the wrong timing

Sometimes I tried to stop the press a bit out of rhythm when I saw a paper misfeed. At some occasions the machine revert a bit and the gripper, with two to three paper in it, tear the packing sheets with its edge. Sometimes it still tears the packing even it not carrying paper. Is there a way to prevent this?

Log in to reply   2 replies so far

If the gripper is tearing the packing as it runs across the platen when it double or triple feeds, it’s tearing under pressure because there isn’t enough clearance for your packing as well as three print sheets. The way to prevent this is to better set-up your feed so your grippers don’t ever pull triples through the press. You cannot adjust the gripper clearance to make them run farther away from the platen surface.

If printing with guides, the gripper arms can also tear packing or your top-sheet off the platen when they close on your print sheet after impression. This happens because the packing or top sheet are positioned off the gripper edge of the platen: make sure they do not overhang the edge of the platen (and that there’s also no topsheet interfering with the movement of the sideguide.)

Thanks for the advise. I guess now I should untoggle the pressure lever first, than disengage the fly wheel lever when the moment is right.