No ink shifting from Yellow to Kay channel. WTF???

[Forty One]

ON my Mimaki JV33 dual CMYK, I had issues where only one of the yellow channels was firing correctly.
The other only had the top half nozzles showing and a few random nozzles.
I few heavy cleaning cycles and general maintinance got it flowing again.

But...

Then I lost half of one Kay channel.
Again, clean cycles and maintanance etc, but now it has completely dropped out.

Everything else is mickey mouse.

WTF is gong on?

 

[DL Signs]

Usually ends up being head caps or dampers when you have to chase problems like that. When was the last time they were replaced?

I'd start with making sure there's ink in the lines, no air bubbles, and dampers have ink in them. I've had a couple of incidents with our Mimaki where it didn't trigger an empty cartridge and sucked a line dry.

if all is good check closely around the edges of the head to see if there's any ink buildup that will prevent the cap from sealing, then replace the head caps. When you run cleaning cycles, if it's a head cap that's no longer sealing it sucks air at the cap instead of ink from the head, and can actually dry the head out plugging even more. You can usually get it back by cleanings and soaking the head, only to have it return.

Dampers have filters in them to catch any contaminates in the ink, if any get restricted it'll prevent that channel from getting ink. When replacing dampers, it's best to replace all at the same time to keep even flow through all. Bottom line is if the head is good and the lines are full of ink, a thorough cleaning, replacing cap tops and dampers usually fixes most other problems.

 

[Solventinkjet]

I agree with DL above. I would also add that these older JV33 models tend to need the ink lines and o-rings throughout the whole machine changed. Anytime I have random ink flow issues on a JV33 or CJV30 I change the dampers, then the damper connector and o-ring and if that doesn't do the trick, I do the whole line.