Problem with print Roland Vs 640

[MaxGD]

Hi Everyone. I am having an unusual problem when I print. I am getting an unwanted stain of yellow ink. It seems that the yellow is getting into the black ink channel somewhere. The stain is usually on the left side (as you look at the printer). I have attached a photo of the test print and also a photo of the problem during a print. If anyone could direct me to what could cause this problem I would be very grateful. The head and the dampers were replaced a while back, but the problem was there before and also those replacements. It is also getting a lot worse recently.
Thanks for any advice. Max

 

[Zoogee World]

If you had this exact problem prior to replacing the head and dampers, then you can rule out the head as the culprit. I don't think it's the cap top either, but has that been replaced since this issue arose? My guess would be some sort of electrical issue or a board or cable issue. During your troubleshooting, have you replaced any cables?

 

[Medina Signs]

I would have to agree with Zoogee - something is telling the yellow channel to spray. I've only changed heads once, but as I remember there are a lot of calibrations to make - if you did not recalibrate after the head change it may have carried over a bad adjustment. I can't tell you what they are as I had a Roland tech do the replacement. Good Luck.

 

[Solventinkjet]

I agree it seems electrical and I would start with the head cables. That being said, I've been doing this a long time and I've never seen a pattern like that on the nozzle test. Something funky is going on.