Advice needed re nozzle dropout

[Forty One]

So, this particular jv33-160 has become my white whale.
So far I've successfully changed it from running BS inks, replaced the ink lines and various consumable parts etc to get it up and running to be a stable solvent printer.
But... I'm having this continuous issue of nozzles dropping out after it goes to sleep over the weekend.
I've replaced the cap top, dampers, capping station.
It's a new head too.
I did have issues where I couldn't get a tight seal previously with the cap top and after a bit more of a strip and clean of the print head plate etc, I've managed to create a good seal.
I normally run about a 2m (8 foot for you imperialists) test print of a colour bar after rebuilding the print head assembly to test if there is any dropouts, alignment, colour issues etc. as you can see I'm getting a good consistent colour and my nozzle test has been good.

But after the weekend, while the printer is not in usee (in this case it was still in remote mode, not power off) I came back and did a nozzle test.
Majority of the Kay channel keeps dropping out and some other nozzles for the other colours are dropping out.

A couple of hard cleans brings back some of the nozzles but not all. And mostly it does not effect the Kay.

Now, if I open up the ink channels with the #test function, and while the machine is powered on, I disconnect the pump and manually pull ink through the discharge hoses below the cap top. This brings all the nozzles back perfectly. Then I can continue printing with no issues.

So...
Is this still an issue of air getting in? Am I still not getting a proper seal? Would the change of the ID of the ink lines effect the flow of ink to the head?

What is creating the drop in pressure that is effecting the supply of ink to the head?

 

[Neil]

Wow, that's a doozy.
That you replaced the ink lines and dampers, I would say look there.
That you replaced the cap top and station, I would say look there.
But, that you can pull ink through manually effectively rules all that out.
Except maybe the line I.D. as you say - if they are smaller for some reason.

It sounds like an air leak, due to the ink gradually dropping out.
Usually not getting a good enough prime when cleaning.
Are the dampers nearly empty?
Do you get good ink pooling in the cap when cleaning?

When you are manually drawing the ink through, you're replacing the pump.
Is it the pump or the lines going through the pump?

 

[Forty One]

It sounds like an air leak, due to the ink gradually dropping out.
Could be. Maybe from the cart end? but I would see bubbles in the line yeah? Or would it just reduce the vacuum?

Usually not getting a good enough prime when cleaning.
Are the dampers nearly empty?
Nope. dampers are full and primed

Do you get good ink pooling in the cap when cleaning?
It's hard to tell because all the other nozzles are firing. Cant single out the black

When you are manually drawing the ink through, you're replacing the pump.
Is it the pump or the lines going through the pump?
I'm pulling ink from under the cap top. The pump isnt an issue as it is also a new one and I'm pulling ink from the other channels.

THoughts...
Could it be the connection between the damper and head? Could it be that theres a leak there?

I've done another test print.
The black has completely dropped out. But there's ink in the dampers.

WHy is it keeping charge after manually puling ink and during print but then dropping nozzles while in rest?

 

[cornholio]

Are you using cheap Chinese captops?

 

[Forty One]

"Chinese". Yes.
Cheap. No.
I've used my same supplier for over 5 years for parts and never missed a beat

 

[rcali]

I have a DCS 7200z and have had nozzle drop outs due to the following:

My print head was seized, easy to tell when using a tube and syringe to try to prime through the capping station and got no ink flow.

There were air bubbles in my ink lines, bubbles in my syringe when I primed through the capping station.

My circulation pumps were dead, unhooking the output tubing on my ink tank and turning on the circulation to see if any ink was actually moving through the tubing and finding out that there was not.

The tank fittings that attached to my ink lines were clogged up, I had cleaned out my ink tanks and replaced my ink lines and dampers but was still having drop outs, I had not replaced the male fittings of my tanks and once I did, I got all my nozzles back.

Hope this helps!

 

[Forty One]

This morning I swapped over the magenta and Kay dampers, did an ink fill and then a test print.

The black/Kay fired perfectly in place of magenta. So I know there's no supply issue.
Magenta in the two centre channels didn't fire at all.

What I can confidently confirm so far is...
1. All ink supply has no issues. No blockages, bubbles, etc
2. After manually "priming" the head (syringe, cap-top etc) it prints perfectly and does not drop out during print.
3. All the nozzles are good. No blockages...
4. The lower section, IE. pump is good and creates suction.
5. From what I can see and assume is I am getting a good seal with the captop.

Letting the machine rest overnight and then continuing a print, no issues.

However, letting it rest for 2 days created a dropout on the majority of all black nozzles and some of the other colour nozzles to drop.

Do I need to work on the captop? Don i just really flush the head out?

 

[Neil]

The last time this happened to me - where I just could not work out wtf was causing similar problem where I couldn't get the nozzles back, I did a head flush and it fixed it.
Pretty easy on the JV33. I put a take away container with paper towel in it in the recess area under the head.
First thing I do is pull backwards to suck out anything in that head channel, then basically massage the cleaning fluid back and forth injecting in and pulling out.
Then put some new clean fluid in and push it through gently, then enough that I can see it spraying with a light behind it.