Komori streaks in solid

[QualityPrint]

We are having issues printing solids on our 6 color komori. I have tried to print this solid (a full sheet size solid) in three different units with the same results. We are seeing streaks about a quarter of the way up the sheet from the gripper that you can see an outline of the colorbar in. The first streak is about 4 inches thick and very pronounced. about 10 inches towards the tail there is another one the same size but is much more faint. The ink we are using is a custom match green that looks sort of like 576. I have gone through the units numerous times to check the nips with no change seen. Dry solids print perfect so it is something involving the water system but am lost. We have an older 8 color that prints these solids with no problem and they are using the same consumables. The roller configurations of these two presses is a little different but nothing that seems huge.
Here are a few things I have tried to narrow down some thoughts:
1)changed ink charge with no change.
2) tried running with less water and more water and it didn't get rid of it.
3) different paper... same thing
4) dumped the fountain solution tank and refilled with no change.
5) turned on the bridge while running with no change.
6)I have also tried different ink and it seems like the ones with transparent white in them show the streaks more.

Any thoughts are appreciated
If you need any more info let me know
thanks in advance

[Cornishpastythighs]

Have you tried adjusting the ink form rollers off of the plate individually one at a time to see if you can identify maybe the one roller that could be causing an issue. It sounds like one of the ink form rollers isn't set to the driven osscillator properly, dry solids would print ok but with dampening added it is not mixing ink/water properly
Just a thought.

[nhprinter]

^^Agreed. Usually if you drop your forms on a very dry plate you'll be able to see the difference if one of them isn't touching the occilator. The ones that are touching will be pretty solid and if one isn't it will have fine vertical lines in it.

I also had a similar problem once and it was the adjustment of a double nip roller higher in the ink train. Ours is a 1985 model though so I don't if this would pertain to yours. I only mention it because if it's doing it in three different units maybe there's one area of the train that was not set properly when the rollers were installed.

Dave

[RKS]

Call Komori and ask them for their streak chart for your press. It will give you the measurements from the lead edge of the sheet and show which rollers are affecting you where. We have it for our LS29 press.

[turbotom1052]

in order to get through this job have your tried to mix your ink formula with a bit of opaque white in place of the transparent white? Opaque white has the ability to hide alot of streaks.

[blazini]

I've only ever run web presses but from what I understand of Komori's most of them use a variation of the Duo-trol water system. I run a Man Roland with a Duo-trol that has issues with circumferential streaks. I'm not sure if a Komori uses an oscillator in it's water system but most of the problems with Dahlgren streaks (what they're generally referred to) is the lack of an oscillator. Once the hard rollers (chrome or ceramic) sensitize or the rubber rollers wear it's transferred directly to the plate. I'd try scrubbing any non oscillating chromes with a scotchbrite and then gumming them and changing any rubber metering rollers.

[techy]

Check form roller settings to oscillator SOP, then re-check with roller facing the plate cylinder gap for final adjustment, then set roller to plate. Plate setting to oscillator should be slightly firmer.

[techy]

I forgot to mention when checking roller setting at gap the roller should be in "on" position. We eliminated streaking on 2/C Komori by this method. Apparently not enough contact pressure to oscillater becomes evident by losing minute surface speed at the gap, just enough to cause streaks.