Question Mimaki JFX200 - yellow stopped printing over the weekend.

[NathanR]

Printer was working fine on Friday when I left the shop, and when I came in Monday and started doing the normal print tests and cleaning in the morning noticed the entire section of yellow was missing in the test.
I should note that I did recently change the main capsule filters about 2 weeks ago but printing has been fine up until today.
Anyway I've spent most of the day running the different cleaning cycles, doing a nozzle wash, head maintenance cleaning, a nozzle soak, and air purge.
I pulled the cover off the sub tank and there is plenty of ink in the tank and as far as I can tell the tank itself seems to be fine.
Working with my boss we isolated the yellow sub-tank and manually and where able to get the ink to start to leak out that way, but after reattaching (running an air purge etc) still no luck getting yellow to print.

We suspect that the filter in the head itself might be clogged on the yellow side but its only a guess so the question is there a way to possibly clean that filter some how or is there maybe something we are overlooking?
We're pretty sure at this point we will need a new head but it would be nice if we could find some sort of temp fix until it gets here.

 

[Solventinkjet]

When you replaced the primary filter, did you attach the supply side, pull ink into the filter with a syringe, and then attach it to the pump side? If not, you probably have a giant bubble in the line that is preventing ink flow which an air purge wouldn't necessarily purge since it's so deep in the machine. Since it sounds like you changed all of the filters and aren't having issues with the other colors, it's probably not this but figured I would mention it.

Have you double checked the positive and negative pressure systems? If not I would check to make sure they are in speck and consistent. Sometimes issues can happen even if it is within spec but it's moving around a lot.

Other than that, if there is ink in the sub tank, no air comes out when you air purge, and you aren't getting any other errors, it's probably the head.

 

[NathanR]

When you replaced the primary filter, did you attach the supply side, pull ink into the filter with a syringe, and then attach it to the pump side? If not, you probably have a giant bubble in the line that is preventing ink flow which an air purge wouldn't necessarily purge since it's so deep in the machine. Since it sounds like you changed all of the filters and aren't having issues with the other colors, it's probably not this but figured I would mention it.

Have you double checked the positive and negative pressure systems? If not I would check to make sure they are in speck and consistent. Sometimes issues can happen even if it is within spec but it's moving around a lot.

Other than that, if there is ink in the sub tank, no air comes out when you air purge, and you aren't getting any other errors, it's probably the head.

So embarrassingly I did not know I needed to pull ink through the filter first but in retrospect that makes sense, so bit of a facepalm moment there.
Once I did that I got about 75% of the yellow channel printing out ink so that was a large chunk of the problem now to see if I can get the non working nozzles firing again.
Once again thank you for the advice it has helped saved many handfuls of hair.

 

[Dasdesignguy]

Be sure you don't install the filter upsidedown. There is a flow direction.

 

[NathanR]

Be sure you don't install the filter upsidedown. There is a flow direction.

That I did keep a close eye on and as far as I can tell it should be flowing in the right direction. After a bit of work it does look like it was just an air bubble that was being extra stubborn.