Air lock i think


I have an Epson 7900 that had a really bad clog in the green line. The ink was like jelly almost. So i removed the line and print head and everything. I flushed everything out with Piezo flush. I put it all back together and got the green working again. But now the vivid light magenta seems to have an air lock. The line from the cartridge housing to the print head is only about halfway full of ink. After i put everything back together i did an initial fill procedure. How can i get the vivid light magenta to fill all the way up? Should i do another initial fill? If there is another way i would like to try that so it doesn’t waste all that ink.


You may need to put an EPSON OEM VLM cart in there and do a CL4 cleaning on the VLM/LC channel pair to verify if it’s truly a damper air-lock or just a miss-aligned o-ring at the ink bay or in the cartridge outlet.



If i do a VLM/LC channel pair cleaning what will happen if it is an air lock vs a miss aligned o ring? What should i look for to diagnose one vs the other? I do have an Epson OEM VLM in there currently.


If it was a miss-aligned O-ring than a CL4 level cleaning (essentially an initial fill of that channel pair) should fix it. If it’s air-lock it won’t.



If it is an air lock what is the best way to fix that?


Replace both the dampers + cleaning assembly. This may or may not fix the issue if the printhead was PRINTED with (like more than just nozzle checks) in this locked state.



Hi Walker,
I have been reading this since it sounds as quite connected with the problems i experienced in my 9900. What is an air lock in the dampers, why might it take place and how can it be fixed?
I do not want to hijack here the post, but the technicians spent two days trying to fix my 9900 and in the end, they had to change the head, and again the dampers unit and the cleaning station… that was after trying all sorts of things, and seeing air that remained in two of the channels in the dampers, no matter how many cleaning - init fills they did…



This is a 9900 in a nutshell:

Air Pressure Pump -> Ink cart -> Ink bay -> Damper Inlet -> Damper - > Head Manifold -> Head -> Pump Cap -> Vacuum Motor -> Waste Ink Tank.

Generally the problem happens at the damper/head/pump/vacuum side of the printer because this has the most complex and moving parts (aka, the head is slamming back and forth thousands of times, the head has a thin film laminated to the nozzles that can de-laminate, and the cleaning assembly is moving up and down hundreds of times).

BUT, if the problem persists this can indicated other deeper problems like pressure pump / cartridge problems or electrical under/over current from the main-board.

The really screwed up part about this whole thing is that often it’s a combination of a few different things that cause an issue to cascade. These printers are built too complex and too fragile. Someone in engineering screwed up. The newer SureColors are better IMO.



I ran several CL4 cleanings on the VLM/LC channel and I could see the ink move some but it did not run long enough to pull it all the way through the tube. When it stopped it would flow back to where it started. Would that indicate a bad o-ring seal or a bad damper or something else. It was working fine prior to fixing the green line. I also believe that the VLM/LC damper may of been one I removed when cleaning the head. Could it be the damper is not seated correct?


If you removed a damper and put it back than there is a good chance this is causing an issue where the vacuum is simply not getting ink through. Generally I only replace the whole damper unit itself on this model and don’t mess with the dampers as they are deceptively easy to miss-align.



Walker, I sent this mail yesterday but have not had a reply from you/the list or the Epson Large format List.
I committed the sin of letting my LLK run out—Cone Colour Pro ink and the chip was reset and still showed 11%ink; my fault for not physically checking. I have put another cartridge in, but now need to get the ink through the tubes. I did all the maintenence things to the capping station and cleaning the print head this morning while in service mode. Must I run an Init fill for the whole system or is there a way to “bleed” the LLK or Y/LLK pair. I have searched the site but can’t quite figure out what to do.

Since I replaced the ink selector in April the machine has worked nicely. Any help will be greatly appreciated.



To save ink I suggest doing a power cleaning on just the LLK/Yellow channel pair. Look at the LLK ink line each time. You should see new ink coming into it. You’ll need a flashlight.

If not luck you’ll need to do an initial fill procedure.



Thanks Walker. Will try, Can I do it a few times or will it cause damage somewhere? Is there any way to do an Init Fill on only that Y/LLK channels in service mode? Roy


Hello Walker, Came right! Did a number of Y/LLK power cleans and just when I decided that was the last one before doing an Init Fill, the nozzle checked perfect! Thanks. Happiness is!