blurr/doubling image '98 K40"

Having a blurr/double image on a '98 Komori 40". On a 25 x 38 sheet it starts 8-5/8 past the gripper and stops at 23-1/2 (doesn't go all the way to the tail of the sheet). From the left and right it comes in 6 to 6-3/4 inches from either side. Sooo...its an area of 25-1/2" wide by 15" long. It is not just a single unit. It is seen whether it is printing on the 2nd or 6th unit. Its not hitting another blanket. It shows more on text weight than cover. Have tried the obvious, sheet compensator etc...Any ideas?? Running this same machine for years, never have seen this.

 

Sounds like you need a gripper service. the sheet could be slipping in the grippers as it moves through the press. Is it a double impression cylinder??

 

Yes its a double cylinder, it doesn't show up on a 20 x 26 text, just the larger sheet. Swing arm or first transfer, what do you think?

 

Does that press have ossentric bearings on transfercylender. or it's a gripper issue on outer grippers

 

I'd start by cleaning the grippers with a wire brush, cylinder by cylinder. While cleaning the grippers, inspect them for obvious damage. If not noticed, clean your swing gripper. This is not too easy and may require some tool manufacturing to get done. ( wire brushes trimmed, etc...) If that doesn't take care of it and you can visually see that the sheet has no bubble in it at the headstops, then I would lean towards a gripper/pad adjustment and replacement. The machine isn't that old and I'm thinking a damaged gripper in either the first unit or swing gripper but that's just my thinking.

 

All stocks do this? How about grain direction, long or short?

Unless the pads are in good condition and wirebrushed every 3 - 6 months you'll end up with poor transfer (there should be a special cam in your tool kit to open the transfer grippers for cleaning).

Gripper wear isn't usually troublesome (they impregnated with industrial diamond dust for a really long life).

But you say it happens on all units and just in specific areas. How about cleanliness of all cylinders? Have you any anti marking material on the transfers? Could be picking up there and just giving the impression (no pun intended) of a double.