Air in the ink supply of Ecotank printers

[stg]

Or may be the right question is how the head should get rid from the air in the damper? As I understand the damper doesn't have a way to take out the air, so, I can think of two possible paths:
1. Through the head while printing (or cleaning, or even flushing)
2. Through the tubes air is going back to the tanks... is it possible?
Very confusing...

And now I wonder if kind of valves on the tubes can help to keep the ink in the dampers.
Probably I can do an experiment and put some valves. If it doesn't work, at least, I can get some answers.

Any suggestions are welcome.

 

[Ink stained Fingers]

There is no ink flowing back via the damper, have a look to it, remove the cap over the cartridges/dampers and get one out. There is a spring loaded valve at the ink exit so ink or air won't move backwards. You take a syringe and push it into the ink outlet, slightly tilted and pull ink with the syringe until the small circular reservoir over the ink outlet is filled to 50 - 70% - don't fill it completely and re-insert it again. Do it for all colors and run a cleaning cycle.

 

[Nour]

There is a rarely covered issue with the ink supply in Ecotank printers, inks are fed via tubes to the printhead, actually to a damper which connects the tubes to the ink receptacles, the dampers, in the printhead. The printhead carriage is not changed vs. the baseline cartridge printers, the cartridges are replaced by dampers which provide some essential functions - feeding the ink to the printhead - filtering the ink with a very fine wire mesh filter - and providing a small ink reservoir.
The inks are not travelling with the printhead - the printer is moving the carriage back and forth - effectively moving the ink with the ink flow in the tubes or against the ink flow in the tubes.
This causes small pressure changes in the supply channels , and these changes are buffered, damped in the damper - with a small (elastic) air bubble and a small ink reservoir which is covered by a foil which can breath.
It now happens over time that the ink levels in the damper reservoirs drop - additional air gets into it, and the ink level drops below the filter, and the printhead is randomly pulling small amounts of air with the ink when printing. This leads to an effect which looks like clogged nozzles with random appearance and cannot really be cleaned away. The effect is very persistent if not taken care of.
But where is this air coming from ? There is no explanation in Epson maintenance manuals or elsewhere. But when you look around to a maintenance manual of Brother printers I found some interesting details. Brother printers use tubes since a long time to supply ink to the printhead, and the Brother printhead is designed such that it can take care of this problem. Brother printheads have an air trap built-in which gets released during cleaning cycles. I'm copying this text from the service manual:

'Liquid ink contains trace amounts of air. These molecules coalesce into air bubbles as the piezoceramic actuators vary the pressure on the ink in the ink-jet head channels. Removing as many of these bubbles as possible before the ink reaches the inkjet head is essential to maintaining proper print quality. A drawing shows how the damper assemblies provide air buffers .....for consolidating these air bubbles away from the inkjet head and vent flow paths for purging them at regular schedule intervals.'

I have observed this effect on about every ecotank printer I was using so far that the ink level in the dampers drops very slowly - getting more air into it, and dropping to a point that random nozzle problems show up. But there is quite an easy fix for it - pulling the dampers out from the printhead carriage and pulling ink into the damper - e.g. filling it up to 75% - with a syringe via the ink outlet, the ink outlet is spring loaded and closes when you pull the syringe away.
This is the damper for the magenta channel of a L1800, you need to remove a cover over the tubes with one srew and pull out the dampers one by one, they latch into the carriage the same way as cartridges would do.

View attachment 13292

Thanks a lot for your detailed explanation!
I have a similar issue with my ecotank et 2720, the nozzle check comes out worse after each head cleaning for all the 3 colors
I checked my dampres as you suggested and all of them were empty, I used a syringe to suck the ink and fill them but I still have the same problem..
It was so disappointing
any ideas?

P.S. the first nozzle check I did I only had a problem with the yellow, after the head cleaning I started having issues with the magenta and the cyan, just to say it's most probably not a printing head issue.

 

[Nour]

There is no ink flowing back via the damper, have a look to it, remove the cap over the cartridges/dampers and get one out. There is a spring loaded valve at the ink exit so ink or air won't move backwards. You take a syringe and push it into the ink outlet, slightly tilted and pull ink with the syringe until the small circular reservoir over the ink outlet is filled to 50 - 70% - don't fill it completely and re-insert it again. Do it for all colors and run a cleaning cycle.

I just saw this note!
actually I filled it partially tried nozzel check and cleaning and didn't work, then I saw a youtube video where they fill it fully so I did that and still getting bad results.
did I mess up my printer??

 

[Ink stained Fingers]

I must admit that I don't have a good view what the current status of your printer problem is and what you got done already in the past so it is quite difficult to advise further actions.

 

[Nour]

I must admit that I don't have a good view what the current status of your printer problem is and what you got done already in the past so it is quite difficult to advise further actions.

Thanks for your reply, and sorry maybe my posts were a bit messy, I'll try again

I'm attaching here the first nozzle check (on the left) and the last (on the right)
after the first one as you see the yellow was completely missing and everything else was perfect, so I did a head clean and the check after got worse. kept repeating the cycle and it was just getting worse.
I saw your post and checked my dampers (first time I open my printer) and they were all empty, the yellow the cyan and the magenta.
using a syringe I pulled ink out to fill the chambers, tried the nozzle check again, got only like 5 segments back, so the problem is still there.

does filling the dampers more than 50% create an issue?
and could there be anything else to do? for example could the connection between the damper and the printhead be clogged? like the connecting part on the printhead side, because at the damper's side I managed to pull out ink smoothly with no problems

 

[Ink stained Fingers]

did you already do a nozzle flushing ? There are plenty of similar videos showing this

50% or 60% is o.k, there should be just some air left as an elastic buffer

 

[Nour]

no actually, I'll try! thank you
I left only a little air bubble in the each damper.. maybe I should take out some ink

 

[Ink stained Fingers]

Nozzle flushing is more important, but since you'll have the dampers anyway in your fingers when you take them out just remove some ink at this time.

 

[Nour]

Nozzle flushing is more important, but since you'll have the dampers anyway in your fingers when you take them out just remove some ink at this time.

I don't believe I almost threw away my printer! It worked!!!!
Thanks a lot