UJF-3042 - Black streaks when printing yellow.

[WalkerP]

I've seen this for a while now, but intermittently. It's not super visible in the image, but you can see black streaks at the bottom of the yellow. It doesn't always do it. I've cleaned the caps, heads, wiper. I'm getting a good nozzle pattern. It is only doing it where yellow is printing (greens, reds, etc) and doesn't appear to do it with C or M. The image is a file where I replaced spot colors to print 100% primaries. I can't seem to find any rhyme or reason.
Any ideas?

 

[WalkerP]

Update: I spoke with another UJF user that has seen this same thing, and it was sporadic with their printer too. They think there is some pressure inconsistency where black ink is being pulled up into the black head from the capping station. The pump and cap appear to be pulling ink just fine. Getting a good seal and can pull ink just fine with a syringe from the bottom of the cap line.

 

[paperstrategies]

Damper needs replacing. Happened to me too. It's a rather cheap fix.

 

[WalkerP]

Good deal. It's not doing it today. I have a couple extra dampers. If/when it starts doing it again.
Thanks!

 

[paperstrategies]

If that doesn't do it, more than likely its your cap top. If there's any corrosion or chips and its not airtight the inks will cross contaminate.

 

[Steve Weist]

Mimaki UV SPECIALIST

If that doesn't do it, more than likely its your cap top. If there's any corrosion or chips and its not airtight the inks will cross contaminate.

I would also check your capping height, if the capping station is to high then the Black/yellow ink that is in the capping station will touch the bottom of the print head and cause this issue. feel free to give me a call and i can walk you thru the capping station adjustment. Steve Weist 615-812-3001