Marks on uncoated stock

Hi
We have a problem when we run uncoated board with the suction tape marking the sheet?
We get by by reducing the amount of suction but does anybody have a total cure?
Heidelberg told me it is a design flaw,
Press is a cd 74 with new style feeder head so basically an xl 75 feeder
When we back up a job say its work and turn the center 6 inches of the job will always leave a mark as the sheet gets pulled on the side lay
Very frustrating

 

Have you tried cleaning the suction tape ? I would suggest a faster drying ink. Some printers add a dryer compound tothe ink in the fountain. The dry ink should not skuff, or mark.

 

If your press is equipped with an aqueous coater you could try coating jobs. Or if you have an extra unit you could overall varnish.

 

Hi
It only happens on uncoated stock so coating is not an option
Surely somebody with an xl 75 gets same marks as our parent company gets it on the new komori with a suction belt feeder
It's not a mark really that adding driers will cure
If you saw the mark live you would know what I mean
Peter

 

This may be true Peter, a picture or short video would help to identify your mark and a possible fix. What type of uncoated stock are you running, text weight or cover weight? does it do the same on both? Have you tried to shorten your pull at the headstop ? You have 2 control knobs on the feed table, I would suggest a possibility of fine tune these adjustments a little more ( make a note of the origonal position before you start ), you can always set them back to the current running position. ( some of the newer models may have 3 knobs on them )

One of the presses I run, has a similar feed system like yours, but not the same model. I hope some of the suggestions I have made, give you something to look at? At times I had run into similar problems and I had adjusted those knobs to a position which I was sure was bad off, but the paper ran fine with no skuff, so who's to say,.... it may be worth trying if you have a little extra paper.

 

Frustrating indeed!

It is a design problem. We coat any offset stock above about 150gsm which avoids the problem, below 150gsm we turn the front third feed tape suction off, when backing up, via the dial on the feed table, although this doesn't always negate the scuff markings.
Failing that we print the job on the SM74...