We've been getting a horizontal bands 8.25" & 10" from gripper. They appear darker than the rest of the sheet. The first one at 8" is barely noticeable but the one at 10" is. The head has a complete new set of ink and water rollers. Plate and blanket packing matches the other 4 heads and the stamped numbers. Vibrator roll sweep and timing has been adjusted all over the map but the best we can get is this faint bar as shown in the picture. It's mainly noticeable on large solids and screens. My press mechanic can't figure it out either. All other heads are fine running the same solution and inks. Has anyone run into this before? Does anyone have a suggestion?

Thanks!

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We get the same thing on our shinohara,, (apparently all shinohara's suffer from this problem)
For us it comes down to the diamater of the water form roller, its circumfrence lines up directly to were the band lays..

If we run a larger ink stripe between the water form and the steel, ie a tigher nip. The band in a solid isn't as noticable.
to check if its your water rollers causing it>
Try running a dry solid,, I bet the band will go away..
Also as your printing a solid, turn your water down till it just starts to scum up along the tail of the sheet.. if the band disapears a bit,, then it will be water roller settings,

If not, double check all your forms too oscillator/plate settings.
and also make sure your oscillator timing is correct.

Hi,

Does the MO have oscillating form rollers and what type of dampening system is it eg. Alcolor or bareback.
What unit is the problem on.

Regards.

__________________
Freelance Heidelberg demonstrator
based in the UK.

Thanks for the replies. We are running the Alcolor system and it shows up only on #2 (Cyan) Head. We have check all of the stripes and even replaced all of the rollers including the water form. The forms are non-oscillating type. The vibrator rolls that feeds the forms are oscillate and we have been all over the timing and sweep adjustments.

Hi,

Do you use any de-calsifier (roller shampoo) on the rollers.

Regards.

__________________
Freelance Heidelberg demonstrator
based in the UK.

Yes we used the Varn decalsifier and have new soft rubber.