Sm74 swinging gripper marking sheet

[Paultheprinter]

Hi there,

Yesterday i ran a job on a 350gsm 395 micron board, they were our companies folders and after production i noticed marks on the tail of the sheet from the swinging grippers on the reverse of the sheet. I have had issues in the past with certain board thickness giving more grief than others, mainly 225gsm and now 350. The board was matt and very prone to slight scuffs even if you run your nail lightly across the sheet a mark was shown, normaly i just remove the guard and clean them and the marking/scratching goes away but because the board was so sensitive i doubt that this would have improved the situation much. My questions are, does anybody have any major issues with this?, does anybody remove the hold down fingers on the front guard to help the sheet from remain flat? does anybody use an antimarking tape on these grippers.
All help welcomed

Paul

 

[rbailleu]

I have never had this issue, but I notice on some newer models they have a roller on the hold downs. can you run a larger sheet to help out. as long as the sheets are straight you could crank up the hold down and turn up the air on the venturi guidance.

 

[madjock]

What I have done in the past to elliminate marking from the swing arm, was to stick small pieces of foam weather strip to the tops of the grippers, it's a bit fiddly, but as a last resort it has got many a job through the press.

 

[Paultheprinter]

Thanks for the input, this problem only occures very rarely and in the past i used some anti-marking teflon tape i stole of the finninshing department and that too worked well but as the swinging gripper passes the sheet to the first transfer/ranger drum they get caught and pulled off.

Thanks Paul