German "Durchstich" refill method for the PGI-520/CLI-521 cartridges

[RMM]

See the pictures on the first page of this post.

 

[PeterBJ]

I tried the bottom fill method suggested by ThrillaMozilla. It doesn't work with a BCI-6 cartridge. If I understand it correctly, then the purpose of both the "Durchstich" and the top-fill methods is to avoid over saturating the sponge and avoid getting ink into the vent chamber.

I used a flushed and dried BCI-6 Y for the test.

I drilled a hole in an orange bottom clip for a BCI-6 cartridge and attached it to a syringe filled with 13 ml of ink. I attached the clip and syringe to the cartridge and secured it in place with rubber bands and started to slowly inject ink from the bottom. The ink went quickly up into the sponge and after 2ml injected, ink entered the vent chamber. Very little ink went into the ink chamber. I then removed the plastic ball sealing the top fill hole. Now ink entered the ink chamber when I slowly injected the rest of it. But then why not just top fill the cartridge with no risk of oversaturating the sponge ? I think the "Durchstich" method is better because of no problems with resealing the top fill hole properly.

The bottom fill kit can be seen here : http://www.amazon.com/InkTec-CB316WN-CB321WN-Pigment-Cartridge/dp/B0031YNEQO

Maybe the method could work with the sponge-only (non-XL) type of HP cartridge ? But I doubt it will work with the XL cartridges if they are similar to the Canon two chamber cartridges.

I guess I'm not the first one to try bottom filling, and find out why the other methods are much better.

Peter.

 

[ThrillaMozilla]

Reply to RMM: Yeah, I see the pictures, but sponge or no sponge, I don't understand why ink doesn't dribble out of that big hole near the BOTTOM of the cartridge. Oh, well.


EDIT: Reply to PeterBJ
Thanks, I see now, I think, although I still don't get why it doesn't leak. I'll have to have another look at the XL cartridges. It would be a lot easier if we could see inside them. I don't know if I'll have occasion to take one apart, since mine are full of ink at the moment. The InkTec kit is sold for the XL cartridges. The directions call for injecting 4 mL and don't say anything about using more for XL cartridges. I saw a report of someone using 8 mL. It makes me wonder now.

 

[PeterBJ]

I don't know why the cartridge doesn't leak through the refill hole, but it is a matter of fact it doesn't. Some forum members are not quite sure of that and seal the refill hole with a piece of tape, just to be sure.

My guess is that capillary forces play a role in keeping the ink inside the cartridge, the sponge acts like a wick, and the refill hole is actually small about 1-1.5 mm or less than 1/16 inch in diameter. If the hole were bigger say 6 mm or 1/4 inch I guess it would leak. I think the ink cartridges with sponges are not simple tanks, I think a lot of physics is involved. Maybe someone who knows more about it could explain it better?

If you cut open an ink tank when it is empty, I'm sure it would be appreciated if you could take some pictures and upload them. Some forum members are investigating the new opaque series of Canon cartridges which look very similar to the new HP cartridges.

Peter.

 

[jimbo123]

once or twice when i accidentally over fill or miss and fill the sponge side i have had a few drips.

been using the german method for over 3 years, over 175 refills, never taped the refill hole, never purged and for the most part never leaked.

J

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Printers: Canon MP830, IP4500, MX700, MX860, MP980
Method: German Durchstich Method
Ink: Hobbicolors ink, PMT-BK, UW8
Misc: Squeeze bottles - so much easier than syringes

 

[websnail]

*in his best Dad voice*

"It's Magic son!"




To be honest I don't know the physics involved in this (and I probably should) but I can confirm it doesn't leak as droplets but that doesn't stop the base evaporating off over time so you would want to seal the hole (and vent) if you're planning on storing the cartridges for extended periods of time.

 

[pharmacist]

Just ask yourself: why does the ink not leak trough the ink outlet hole ??? It is not only in a lower position compared to the durchstich refill hole and we all know that something lower will experience a higher pressure rate. Secondly: the resistance is lower when the diameter of the "tubing" is larger and.....the ink outlet hole is much much larger hole compared to that tiny durchstich refill hole a few mm's higher. So those fearing leakage should much more concerned about leaking through the ink outlet hole based on these two physical laws.....But it doesn't, so something else must cause this static behavior of the ink sitting statically inside the cartridge.

 

[stratman]

...something else must cause this static behavior of the ink sitting statically inside the cartridge.

Me: I'll take Sponges for 200, Alex.
Alex Trebek: And it's the Daily Double!

Yes, everything revolves around pressure (partial pressures) of the air and ink inside the cartridge in relationship to the pressure of the atmosphere around the cartridge. Throw in the sponge to alter the equation and viola - no leak.

Increase the pressure within the cartridge, by squeezing the catridge or over filling with ink or blowing air into the cartridge, and you get a leak. Remove the sponge and its electrostatic/osmotic/whatever effect and you will get a leak even when all other parameters are kept the same.

Now, back to Jepardy! -

Me: Flow of Fluids for 1000, please.
Alex: Differences in flow of fluids related to pressure and tube diameter.
Me: What is the Bernoulli Equation?

 

[ThrillaMozilla]

OK, I think I have it figured out, but I don't have time to describe it now. Basically, I think there's usually a slight vacuum in the reservoir, but there's more to it. It might be worth understanding this further.

Meanwhile, can anyone tell me if the extra large cartridges have the notch shown by the arrow, on the top side? (This one is not an extra large cartridge.) Unfortunately, all my HP564XL cartridges are in use, so I can't take one apart.

By the way, is this a commercial durchstich system?
http://www.youtube.com/watch?v=oUz4va8WyLM

 

[PeterBJ]

Excellent picture ThrillaMozilla

It looks like the partition between the chambers might be the same part as used in the XL carts, just turned upside down, so there is no way ink can be transferred from one chamber to the other. My guess is that the XL cart has the notch on the bottom, so the XL cartridge is similar to the Canon carts. A notch on the top would allow air to enter directly into the ink chamber from the vent chamber, and I'm sure that would cause leaking, as would a top fill hole not sealed properly. I look forward to a picture of a XL cart to see if my guess is right.

Please post your theory when you have got the time. I think you are on to something with the slight vacuum. Your good question of why a cartridge doesn't leak through the durchstich hole really got me speculating.

If the video shows a commercial version of the durchstich method, I think they got it completely wrong. They miss the crucial part of only injecting ink in the ink camber and not forcing any ink into the sponge and afterwards let the sponge passively suck up ink, so it is not getting oversaturated.

Peter.