JV33 Printhead drop colour questions

[Andrew Signs]

Hi All,


So I have searched around and tried to piece this together. I'm having a range of issues with one of our JV33s (we run several).

Main points

- One side of black is not firing (left hand side) - 100% not firing.
- After a few cleans and washed I got a couple of nozzles but only until we did the next fill
- It was functioning fine until yesterday
- The head cables were replaced today
- Ink is flowing to the damper - confirm by opening valves and letting flow
- Pump is brand new put in 2 weeks
- Capping new

We have done al the normal head cleans, fills etc with no luck. The odd things are below;

- It seems to me that the damper on that black channel isn't 'sucking in' as other the others do
- I swapped the two black dampers to test if it was the line. Following this the same left side still doesn't work even with other line/damper
- To test, we manually primed the head with black on the side that wasn't working. This worked and ink fired as normal but no ink pulled into the head therefore is only used what was available in head.


So...this leaves me questioning what to try next. I know everyone always falls on replace the head and just want to see if I've ticked all the boxes before we spend the money on it.

Any help wold be greatly appreciated.

Thanks!

 

[HaleYeah]

Do the JV33 Have the DX4 Heads?

 

[Solventinkjet]

This is a great example of what to put in a tech request post.

Unfortunately it's probably the head. However, make sure there is not a crack in the manifold where the damper is installed. Even a slight crack will allow air into the system and this makes it so air gets pulled instead of ink. Manifolds are replaceable and much cheaper than the head itself.

The fact that it still doesn't print when you swap the dampers tells me that channel is damaged in some way. Could be the membrane that separates the two blacks is broken. It's easier to tell this if the membrane breaks between two channels of different colors because you can see it in the nozzle test. I have seen many times in the field where the membrane broke and it killed one channel either partially or completely. The fact that it printed after a manual prime means you got ink to the nozzles but it wasn't able to hold the pressure properly and dropped out again.

One off chance fix I can think of is that the channel dropped and then coincidentally the pump or cap isn't pulling ink down properly so the black just hasn't had a chance to properly prime. Double check that when you run a cleaning cycle that ink is actually coming out of the waste tubes. It's easy to put a pump in backwards if you don't have a lot of experience with it. It should have a pretty steady flow coming out.

 

[Andrew Signs]

Thank you Solventinkjet for the information. It will be a great help when we have a look over it tomorrow.

I gather from what you have written its work us putting the head that is having this issue, onto a new manifold (being the black plastic area) and re-attached dampers and prime. We have these parts around so I may as well try first.

Can you confirm when you are talking about a channel membrane that this internal to the head?

Thanks!