Falcon II Nozzle dropping out on new head

[Graphics2u]

My Magenta Head keeps dropping nozzles during the print. I printing logos roughly 30" sqare and about half way into the print I start getting banding lines from nozzles not firing. This is a 2 month old head that has printed perfect since I installed it. Replaced the dampers at time of replacement and just today again. Still having the problem. Dampers are plenty full of ink. It's only the magenta head doing this so it's not a feed problem. Just looks like gradually 1 then 2 then maybe 3 nozzles stop printing.

Any ideas?

 

[letterman7]

Almost sounds like there is gunk in the feed lines. A pain, but try flushing the magenta line from the cart to the head, flush the head (not recommended, I'm sure, but I brought a head back by forcing cleaning solution through the damper nipple. Make sure you've got towels handy!), and re-priming the head via the suction method.

 

[randya]

Is it always the same nozzles?

Does it clear up immediatly after a clean?

Make it drop out and the stop the printer - do not allow the print head to cap, drag it down to the left side and see if ink is pooling on the bottom of the head where the nozzles are dropping out.

 

[Graphics2u]

quote=randya

Is it always the same nozzles? Hard to to tell because by the time you stop and then try to do nozzle check manytimes they are all working again. It's like it needs just a little time for the ink to fill the head. But a couple times i have been able to tell that at least one of them is the same nozzle each time.

Does it clear up immediatly after a clean? Clears up after just a minute of not printing, usually I don't have to even clean it. The next print starts off perfect and half way through the lines start again.

Make it drop out and the stop the printer - do not allow the print head to cap, drag it down to the left side and see if ink is pooling on the bottom of the head where the nozzles are dropping out. How can I stop it without it capping? It always returns to the capping station.

And this is a newer head and brand new dampers!

[/quote]

 

[randya]

Normally, you can lift the cover to stop the machine, if you have overridden the cover sensors, it may be work activating them for a short time.

Sounds like you have an leak in the ink line.
I suspect that if you stop the machine you will find ink puddling up on the head covering the nozzles and causing the drop out.

You may also see ink dropping on each side as the carriage changes direction.

A leak can be caused by overtightening the connectors (or not tight enough) you may want to try new o-rings. And in severe cases you may have to trim a bit off the tubing if it is too distorted.

If it is a leak up line, you should be able to see air bubbles in the line, if it is at the dampers, it will not be so evident.

 

[Graphics2u]

Normally, you can lift the cover to stop the machine, if you have overridden the cover sensors, it may be work activating them for a short time.

Sounds like you have an leak in the ink line.
I suspect that if you stop the machine you will find ink puddling up on the head covering the nozzles and causing the drop out.

You may also see ink dropping on each side as the carriage changes direction.

A leak can be caused by overtightening the connectors (or not tight enough) you may want to try new o-rings. And in severe cases you may have to trim a bit off the tubing if it is too distorted.

If it is a leak up line, you should be able to see air bubbles in the line, if it is at the dampers, it will not be so evident.

The cover sensor on mine is bypassed. but I might undo it to check this out.
Would the dampers stay full if there is a leak in the line? And why would a leak in the line cause ink to puddle on the bottom of the head? I not doubting this could be the problem, i just thought if you have a loose fitting you lose vaccum and the ink will syphon back into the cartridge.

 

[randya]

It is extremely rare that will ink siphon back into the cartridge, the carts have mylar bags in them and they are slightly higher than the head itself so that gravity feeds the head.
(next time you get an empty, break open a cartridge and the mylar bag is doublesided taped in the housing, you can rip out the bag and put the shell in the recycle bin).

With a small air leak, the head can be slightly overpressured so that the droplets do not form properly and instead of dropping, will stick on the nozzles and collect forming a small puddle.

Of course, there are some other causes of this (head issues, head rank, firiing curve) a small air leak is the most common.

And it is such a small amount of ink, that there can be no visable change in the damper level.