Roller marks same place all Units komori l528

[tijohnn]

Yep, we have a big problem with a komori lithrone l528 2003. We have 2 Stripes on my sheet like a roller mark. The first mark is at 4 15/16 in to the gripper and the second one is at 10 1/2 in. The first one is black and the second one is white. I have this 2 stripes on all units at the same place. We see this stripe only when I print more than 60% screen. I did many test and I don't resolve my problem. I tested :

1- Changed my Dampening Rollers and ink Roller.
2- Check all nips to make sure that respect the specs
3- Check packing with packing gage, everything is ok, we have 5 sheets of 8 mm.
4- Change the timming, no changement
5- Try a order brand plate, no changement
6- Try different blanket hard and smooth surface
7- Try a different ink and fountaine solution, same result
8- I removed the pressure betwen form roller and plate, no result
9- I removed the pressure betwen occiator and form. no result
10- I verified all of bearing. Everything look good.

If people see a solution, please let me know.

Thanks

 

[RichardK]

Did you try a dry solid? If the marks are still there it rules out the damp.

Do you have oscillating forme rollers (it's an optional kit for difficult solids/tracking/ghosting). If they're in replace with standard or lock them to non-oscillate.

Did you try reducing tack? 2nd mark could be a shock mark from the sheet transfer.

This affects many Komori's - in fact there's a 'cheat' sheet that engineers use to identify the culprit roller or transfer mark. We could use one of those for both L26/28/40 as a sticky on the forum...any kind member got one to upload?

 

[tijohnn]

answers

Did you try a dry solid? Yes, we try to print a dry solid and we don't see the shock mark. But I tried to change the configuration nips more and less pressure and it's the same result. We also change the metering and form for a brand new, same result.

Do you have oscillating forme rollers (it's an optional kit for difficult solids/tracking/ghosting). Actually I change the shaft occilator for standard shaft, but I did not set

Did you try reducing tack? I try different kind of ink, the tack is approximatly the same, It is possible for you to explain me why if I reduce tack we will resolme my problem. The tack is différent betwen the black,cyan,yellow,magenta. And we find the same probelm at the same place. 2nd mark could be a shock mark from the sheet transfer. I mesure the transfert point dirrectly on the press and the transfert point is 2 inche before my shock mark.

I have a really weird problem.

This affects many Komori's - in fact there's a 'cheat' sheet that engineers use to identify the culprit roller or transfer mark. We could use one of those for both L26/28/40 as a sticky on the forum...any kind member got one to upload? where ?

 

[RichardK]

You're not getting the mark on a dry solid...this eliminates the inkers and points to the damp. Are you running copper rider rollers (try taking them out).

Are your forme dampeners geared to the chrome oscillator?

The reason to add reducer is to make the release from the blanket easier and so reduce the transfer shock mark.

What fount/alcohol combination and % are you running?

 

[tijohnn]

You're not getting the mark on a dry solid...this eliminates the inkers and points to the damp. Are you running copper rider rollers (try taking them out).Yes and we did'nt resolve my problem.

Are your forme dampeners geared to the chrome oscillator? Yes and I tried without gear and it's the same result.

The reason to add reducer is to make the release from the blanket easier and so reduce the transfer shock mark. Thanks, I will try

What fount/alcohol combination and % are you running? I use a alcohol Subtitut from Anchor ( ARS-JP ) with fountain solution ( Emeral JRZ ) from Anchor. We use 3oz fountain solution for 2oz. Alcohol subtitut. We tested different compagnie and we have the same result.

 

[danakomori]

Here's the charts I have




hope this helps
-Dana

 

[RichardK]

Dana you're a star

This should be a sticky for future reference.

 

[jonnyt0125]

Try cutting the tail of the packing at an angle. Or make each packing sheet longer than the next as to "stair step" them.

 

[dearne]

Help

Hi Can anyone please tell me where the charts that danakomori posted have gone would love to see them.
Thanks
De

 

[Yeslek]

If the machine has bridge rollers try removing them.