How long before a depleted Canon Oem cartridge goes stale?

[pebe]

Excellent post pebe!

Still trying to digest all the implications and ways to test your contentions.
But I do comment that how long the ink inlet hole is left open during the refill process
may be another variable I don't quite understand. But I do believe you are going in the right direction in possibly deepening understanding. I also now wonder if having a two piece sponge like in a Canon OEM cartridge may be an actual detrement to making the cartridge a good refill candidate.

But I do point out that the top Canon sponge showed an excellent ability to wick up hobbicolors ink and wonder if other inks are not as easily wicked up?

And also wonder why a leaking ink inlet hole seal so screws up tbe behavoir of the cartridge.

Yes, I agree on the need to seal the tank inlet as quickly as possible. This is why I seal the vent after the sponge is 50% covered. As I then fill up the tank, a backpressure will build up in the sponge compartment that will tend to resist any further flow of ink in from the tank - or at least slow it down - before I can get the inlet sealed.

The inkJet carts do not appear to have a two part sponge so it may not matter if their sponges are half filled or fully filled. I have not experimented but will do so at the next refill.

I think the leaking inlet hole seal can be explained like this. The tank has no effect on the pressure at the cart outlet when the filling inlet hole is sealed. The outlet feed and the transfer port will both be at atmospheric pressure. But a faulty seal that allows air into the tank will change it from a chicken hopper into a gravity fed tank with a 1 head. That raises the pressure at the transfer port higher than the outlet feed and ink will pass under the sponge and drip out.