Need Help Mimaki JV150-160 wont output black color

[kyonthinh]

Hi guys,
I need some helps with the Mimaki JV150-160 in my company.
I was printing today and halfway through the black color disappeared. I printed the test patern and it printed only the other 3 colors (6 paterns). The two black paterns are null. I ran bunch of head wash and nozzle wash and suddenly it came back, test paterns were good, then it disappeared again during the next printing session. Now I dont know what to do next. Can you guys help me? Thank you very much.
The test on the bottom was the first test, and the top one was the second. The 3rd test now looks like the first one.

 

[Solventinkjet]

The first thing you want to check is if there is actually ink in the black cartridge. Sometimes they are empty and don't flag the printer properly. If that's not the issue then I would suspect the dampers need to be changed.

 

[kyonthinh]

The first thing you want to check is if there is actually ink in the black cartridge. Sometimes they are empty and don't flag the printer properly. If that's not the issue then I would suspect the dampers need to be changed.

I have check and changed to new cartridge, both have 100%, no chance.
So it is the damper? Do I need to change all dampers or only the one for black channel?

 

[netsol]

other than cost, there is no down side to a new set of dampers
solventinkjet sells a really nice tapered syringe, perfect for pulling ink into the new dampers