if its doing it on all stocks (thick and Thin) i wouldn't think you have badly set Grippers but maybe you inp cylinder bearing is stiff and not Moving very easily.
or on the other hand although it may sond like a simpletons answer but if you have recntly changed the blanket, check to make sure it is tight and not slack off the cylinder
Doubling is typically caused by:
Gripper settings incorrect
Unstable paper - ink/water balance - too much water
Loose plate
Loose blanket - tighten blanket clamps, adjust packing, or replace blanket
ok, so doubling it is. for some reason i was under the impression that it was slur. all these years ive had my terminology wrong, that's embarrassing lol.
anyway, i checked and re-checked all my grippers, cam followers and such from the infeed back to the transfer cylinder after the offending unit and everything seemed fine. it's the third time ive checked them in a week. the blanket is properly torqued with the correct packing. i did however recalibrate my plate clamp to zero setting and ran some sheets at various speeds and the problem seemed to go away. i highly doubt the clamp pressure was the cause but i think it might be possible that the clamp wasn't tightening enough allowing the plate to move while under impression. i cant find anything else wrong. there has to be a better explaination.
Slur and doubling are very easy to confuse. With slur the halftone dot looks like it has been smeared usually in the direction of sheet travel through the press. With doubling you'll see a very good faint reproduction of the dot following it usually in the direction of sheet travel through the press.
The photo of your colorbar shows the very clear second ghost image of dot doubling rather than a smear of the original graphic.
Hello again,
I think you need to get a qualified tech to check your gripper systems. If the problem is every sheet then it must be coming from a single diameter cylinder, most likely culprit is the perfector.
Hello again,
I think you need to get a qualified tech to check your gripper systems. If the problem is every sheet then it must be coming from a single diameter cylinder, most likely culprit is the perfector.
yeah i was originally thinking it was the impression cylinder grippers but i found nothing wrong there. i never thought to check the perfector. i'll have to check that first thing tomorrow.
well i checked the perfecter grippers and theya re all fine.
havent seen the issue though since ive not ran anything over 10500sph
ive got a larger run coming up so i will see what comes up with it hits press
Albert,
How is the infeed. Check the front lays for squareness and gripper bite. Even if they are indicating square on the console display, put a sheet in the infeed and check the gripper bite to see if the lays are actually square.
I still think you are going to need some help though. When and if the problem happens again could you send us about 100 samples making sure that they are in sequence and show what happens as you increase the speed of the press. Mark them to my attention and I will find out what is happening on your machine.
Albert,
How is the infeed. Check the front lays for squareness and gripper bite. Even if they are indicating square on the console display, put a sheet in the infeed and check the gripper bite to see if the lays are actually square.
I still think you are going to need some help though. When and if the problem happens again could you send us about 100 samples making sure that they are in sequence and show what happens as you increase the speed of the press. Mark them to my attention and I will find out what is happening on your machine.
i will check them again tomorrow and this time also check for infeed bite
as for the sheets, i will most definitely do that the next time it happens.
i think the manager and other operator think i'm out of it since neither of them have seen it happen in real time (only the couple of sheets i saved)
Linear Mode
