Strange lines in VS-540 prints

[Ed's Sign]

I have a Roland VS-540 at the shop i'm at and I've noticed lately that I've been getting some strange lines across my prints. It not banding as they are inconsistent and mostly just show up in certain solid colors. The file i'm printing from is a vector graphic and the green is a solid color with no gradients. We have just gotten a new head and dampers a few weeks ago, and my nozzle test is perfect. I've made sure the calibration is correct and tried cleaning the encoder with alcohol, but so far nothing has changed. Any ideas what might be causing this?

 

[Ragnabrok]

how does the edge look? if it's supposed to have a square edge, is it square? Is it stuck on high head height, or the wrong profile?

If you print on unidirectional, does it go away?

 

[graphx70]

It looks like bad bidirectional calibration. Try it first

 

[Malkin]

We've had this happen when the media roll was still quite full & heavy, and we had removed many of the pinch wheels. The outermost pinch wheels are not strong enough to advance the vinyl properly when the roll is heavy, and it resulted in the inconsistent banding like your photo.
Putting all the pinch wheels back in place fixed the problem instantly.

-Ted

 

[Morph1]

are those lines in x axis or y axis,
I have problems like this some time with Arlon DPF 6000 xrp...
Its a vinyl batch that's faulty , a surface damage absorbing inks differently..