The role of one way valve and air in the line

[tkonto]

that's a sign for a problem - where is all that air coming from - something is not airtight between the tank outlet and the cartridges - that much air will not pass through the nozzles

Just a clarification.

It is not the whole ink returning back.

Part of the tube gets drained ( about 10% to 15% measured from the cartridge) and the print head is not able to suck enough ink to refill the line.

If I place the bottom of the tanks at top of the catridge height, no issues (have not tested yet for ink leaks though).

Assuming that gravity plays no role and the vacuum length in the line should be nill, maybe I have a suspicion about the root cause.

Air leak between the cartridge and the print head thread (the point of the print head that is inserted into the cartridge to "suck" ink).

Could it be?

 

[Ink stained Fingers]

Could it be?

Sure, that's a possible path for the air.

Raise the ink reservoirs to a level that ink is not flowing back but stays at an equilibrium, and reduce the level from there by half an inch, there should be a slight underpressure for the nozzles to pull ink , it's the hydrodynamics at the nozzle exit - ink is pushed out and creates a pull effect on the ink for the next ink shot. It's a matter of small pressure changes in the ink channels. Genuine Epson cartidges have an internal membrane/air pressure valve for this purpose

 

[tkonto]

Sure, that's a possible path for the air.

Raise the ink reservoirs to a level that ink is not flowing back but stays at an equilibrium, and reduce the level from there by half an inch, there should be a slight underpressure for the nozzles to pull ink , it's the hydrodynamics at the nozzle exit - ink is pushed out and creates a pull effect on the ink for the next ink shot. It's a matter of small pressure changes in the ink channels. Genuine Epson cartidges have an internal membrane/air pressure valve for this purpose

Oh well, sometimes we need to go back to the basics.

Apparently, at some point, I filled up ink through the air chamber and not through the ink chamber.

Add to that that I long ago forgot the tanks are basically Mariotte bottles and this is how a year-long problem is now solved!

Primed the system, rebalanced after refilling, and that was it.

For the last two weeks, I have been printing all colorous without any problems.

Thank you for your time and hints.

 

[Ink stained Fingers]

thanks for the good news .