Sealing the refill hole BCI-6 BCI-3

[Nifty]

Guys, thanks so much for your images... "a picture is worth a thousand words"... well, it's true and I'd rather spend 2 mins taking / posting a few pictures than typing 5000 words!

By the way, I've copied your posts into the nifty-stuff gallery and edited your posts to point to those images. This will make sure that the images are always available.
http://www.nifty-stuff.com/gallery/inkjet-refill-1

 

[Nifty]

Well, I can't let you guys have all the fun, now can I!?

Here is a Arrow cartridge from alotofthings.com.

The first thing I noticed is there is just one sponge and the filter. Second I noticed that the main sponge is EXACTLY like these man made chamois that I have, same color, same texture and feel. Finally I looked at the little "filter". If I hadn't read Grandad's post I would have thought this thing was plastic by the feel of it. Closer inspection does remind me of cigarette filters.

 

[BlasterQ]

if that sponge is comercially available in the supermarket, then we can even extend the life of the cartridge and refills even longer! we'll just have to find a cartridge that can be easily opened and resealed.

 

[Grandad35]

I would like to give an update on the sponge tests, and I apologize in advance for the extreme length of this post. I also hope that this is of interest to more than just a few people.

Before starting, a more detailed explanation of the problem is probably in order.

The bottom sponge does not "go bad", it just "goes empty". To understand the problem, it is first necessary to understand surface tension and capillary action - the attached link is technical, but there is no way to avoid a technical discussion if you want to understand what's happening in the sponge:
http://hyperphysics.phy-astr.gsu.edu/hbase/surten2.html#c5

"Surface tension" is the tendency of a liquid to hang together. The most common example is when you slightly overfill a glass, and the top of the water goes above the top of the glass without spilling. The water's "surface tension" keeps the water from spilling over the edge. The same effect allows water bugs to walk on water, causes water to form drops, etc. "Capillary action" is what pulls water up into trees, and is related to surface tension. These are small forces, but they are still very important in our everyday lives.

If the bottom sponge is full of ink, the tendency of the ink to stick together pulls additional ink from outside the sponge (if it is there) through the sponge's cells to replace any ink that is pulled away by the filter/print head. Once the outside source of ink is depleted, the ink that is pulled from the cells is replaced with air. When this happens, the surface tension effect is lost, and additional ink will not be drawn into the sponge when the ink chamber is refilled. In fact, a closed cell foam (like the bottom sponge) will actually tend to repel ink after the cells are full of air.

For those who are interested in seeing this for themselves, dissect a cart and carefully wash out the ink from both sponges by repeatedly squeezing and releasing them while under water. Then squeeze them as dry as possible and place them in water for 10 seconds. The top (open cell) sponge will absorb a reasonable amount of water in this time, but the bottom (closed cell) sponge will absorb almost nothing. This is why Neil stated that carts that get air in the sponge are dead - it is difficult to get ink back into the cells again. That it is possible to get ink back into the sponge can be demonstrated by a simple test. Carefully fold the bottom foam until it can be tightly squeezed between your thumb and forefinger. Keep it tightly squeezed and put the sponge into a container of water until it is completely under water, then let it go. The sponge will now expand, and it has no choice but to pull water into the cells - it will now be completely filled.

For those with experience refilling HP foam filled carts (including 56/57/58), it is well known that letting these carts go empty is also usually the kiss of death. Fortunately, methods have been developed that sometimes allow an empty HP cart to be salvaged - my personal favorite was "slinging". It involves refilling the cart, placing it into a plastic sandwich bag and then placing the bag into the bottom of an old tube sock with the print head toward the bottom. Take it outside and away from anything that wouldn't benefit from some ink droplets (in case the plastic bag doesn't do its job) and swing it around in whatever plane is most comfortable for you. Swing it as fast as you can for 20 seconds or until your arm hurts. Depending on the length of your sock and the speed of your swing, this motion can easily generate over 10 G's. This makes the ink 10 times heavier than normal, making it much more effective at forcing ink into the foam and pushing out the air than just gravity alone.

The "SlingTest" photo shows the bottom of a cart before and after "slinging". The image on the left shows air around the filter, and is normal for this non-OEM cart. This space is filled with ink when the cart is new, but it soon empties, as it seems to be the first ink used. The image on the right shows that slinging has been pushed the ink lower into the cart, even if it did not completely fill the air voids.

The next step was to use a similar refill technique to that used in the HP foam carts - to inject ink directly at the bottom of the foam. Previous photos showed a "hole to nowhere" in the sponge chamber cover. This is a good place to put a second hole into the sponge chamber. The same type of self tapping #6 flat head screw that was used to seal the ink chamber was simply screwed into the cart to make the hole, then it was removed. A syringe with a 1.5" long needle was inserted into the hole at an angle to put the tip of the needle as close to the exit port as possible. The "Refill 1" image shows the original cart on the left and the needle in position on the right. Note that the top sponge had very little ink in the left image.

Inject the ink slowly to give it time to spread as much as possible. In this case, I was able to inject an additional 4 CCs of ink. If you remove the screw from the ink chamber before injecting the ink, some of the ink will be pushed back into the ink chamber, filling it at the same time. Plug this new injection hole with the screw when you are done, since it is a larger hole than the vent hole and two holes will allow some ink to leak from the sponge chamber if the cart isn't always stored correctly. The condition of the cart at this time is shown on the left in "Refill2". Note that the top sponge is now full of ink and that some ink has been forced into the air void around the filter. This cart was then given the "sling treatment", and is shown on the right side of "Refill 2". The air void has also now been completely filled.

Since there is now a lot of free ink at the exit, you should allow a little more time than normal for the carts to "drip" after they are refilled. I also like to print a few copies of a heavily colored test image onto plain paper after installing newly refilled carts just in case there is initially too much ink at the exit (often the case).

I applied this treatment to a set of carts that had become marginal - they would sometimes give the strange color bands typical of carts that don't feed enough ink, especially after a cleaning cycle. They now give the same print quality as new carts. If someone has a set of "completely dead" carts, they might want to try this technique on them and report the results.

Even though this technique seems to help with air locked sponges, there may be even better solutions.

http://www.nifty-stuff.com/img/files/SlingTest.jpg
http://www.nifty-stuff.com/img/files/Refill1.jpg
http://www.nifty-stuff.com/img/files/Refill2.jpg

 

[Nifty]

This "sling method" is similar to the centrifuge inkjet refilling / cleaning machines. Instead of sucking or pushing ink and/or cleaner into a cartridge the cartridges are placed into a machine that rotates them at a high velocity forcing ink into and distributing equally throughout the sponge.

 

[Grandad35]

Nifty-stuff - What other methods do you know of that are used by recyclers/manufacturers to distribute ink into the sponge? I was not aware that they used centrifuges. That is an elegant solution if you happen to have one of those lying around the house.

My wife saw me looking at the spin cycle on our washing machine, and now I am banned from even touching it.

 

[Nifty]

haha.... can you imagine your wife finding a leaking cartridge in the spin cycle? Actually, my wife half expects it by now.

Somebody want to buy me one of these for Christmas?
http://www.thaifrance.com/TFE/Centrifuge.htm

FYI: For dry erase markers, or other felt tip type markers you can bring them back to life (if just temporarily) by tying / taping the non-writing end to a shoelace or string and spin it around and around. Forces the ink from the sponge in the pen body to the tip.

I use to use a tool with my Lexmark cartridges that sucked ink out of the exit hole and pulled ink into the sponge. This also worked very well for unclogging the built in print head on the cartridge. I wonder if a modified syringe with a piece of large surgical tubing could be fit on the end of a BCI-6 cartridge to draw ink into the air pockets in the sponge.

 

[ocular]

So why do the OEM cartridges have the two sponges?
Do the cartridges with the single sponge - like the arrow have a longer refilling life than the 2 sponge cartridges?
I feel that it is more than just air in the sponge that limits the life of the cartridge. Its likely that when the sponge becomes dry the ink solidifies on the sponge and creates air pockets that are locked in.

A CFS with the cartridges always full overcomes premature sponge failure.

I reckon a technique of washing the sponge clean in situ and allowing it to air dry and then refilling with ink would rejuvenate it. Perhaps dripping thru a solution made up with windex or ammonia and then flushing with water and allowing to dry would do the trick.

 

[BlasterQ]

I still have to try refilling, but I'm learning more and more about it everyday here in this forum, I feel like I've done it many times already!!!

 

[Grandad35]

Nifty-stuff, That is some serious looking equipment, but $621 to revive a few carts may be a little expensive for the casual user. I assume that the venturi ejectors mentioned on their refill machines are the devices that generate a vacuum using compressed air, and that they use a vacuum in their refill process.

Ocular, I believe that the reason for two sponges is that the open cell foam on the top does a good job of uniformly distributing the ink across the top of the bottom sponge when the sponge chamber is initially filled (but this is only speculation on my part). So, why not just use a one piece open cell sponge? If the bottom sponge used open cell foam, the ink would just drip out.

It makes sense that a CFS (that doesnt overfill the sponge and cause leaking) will keep the bottom sponge covered with ink, so it will never pull air into the cells and should last a long time. Likewise, if you refill each cart when your ink chamber has of ink left and you add another few CCs to the sponge chamber at the same time, you should have a similar situation where the bottom sponge stays covered.

The top sponge was relatively easy to flush, but without physically squeezing it, I could not flush out my bottom sponge. Since you already have the sponges out of your cart, see if your sponges act the same.

Because there should always be at least some liquid ink in the cart and there is almost no air movement into or out of the cart, the air in the cart should always be at 100% relative humidity and therefore shouldnt dry out the sponge. It IS possible that the ink will chemically attack the sponge over time and cause it to disintegrate, however.

BlasterQ, Youll have to give refilling a try. Youll print a lot more pictures when you are paying less than 5 cents per 8x10 for ink. Even adding 15 cents/sheet for Kirkland Glossy Photo Paper, your total costs are less than 20 cents for an 8x10.