FLUSHING....WHY?

There is a series of pictures by mikling which shows very clear how the lower and upper sponge/fiber works in practice, how they are sucking ink and not dripping, and that the upper is more hydrophobic than the lower because the upper is for breathing/air exchange while only the lower is for ink transfer from reservoir to outlet...
http://www.printerknowledge.com/threads/do-i-have-a-problem-with-dry-sponges.6058/page-7
First the upper sponge would "empty" - while it looks saturated it is not. Then the reservoir would empty - now the upper sponge is only for "breathing" and the lower transfers the ink

PS: and for the scientists among us in post #93 there is a link to the canon cartridge patent, exhaustive reading...

Interestingly I noticed the dif between lower and upper relative to how the ink reacted to them but had not read extensively enough at that point to understand how specific the design was in that regard.

martin0reg said:

There is a series of pictures by mikling which shows very clear how the lower and upper sponge/fiber works in practice, how they are sucking ink and not dripping, and that the upper is more hydrophobic than the lower because the upper is for breathing/air exchange while only the lower is for ink transfer from reservoir to outlet...
http://www.printerknowledge.com/threads/do-i-have-a-problem-with-dry-sponges.6058/page-7
First the upper sponge would "empty" - while it looks saturated it is not. Then the reservoir would empty - now the upper sponge is only for "breathing" and the lower transfers the ink

Click to expand...

From my observations:

1. On the first fill of a purged/dried cart, the ink fills both felts if it is given enough ink.
2. As the ink is used, the top felt is emptied first without pulling ink from the ink chamber. The bottom felt simply acts as a conduit for the top ink.
   
3. Once the top felt is completely empty, ink is them pulled from the ink chamber without lowering the ink level in the bottom felt. Again, the bottom felt simply acts as a conduit for the ink chamber ink.
   
4. Once the ink chamber is empty, ink is pulled from the bottom felt, introducing air. This design guarantees that a minimum amount of ink will always be available once the prism is uncovered.
   
5. I didn't find the upper sponge to be more hydrophobic, but I think that the physical break between the two felts and the location of the top of the vertical grooves close to this break have a lot to do with how these carts operate.
6. When refilling, the break between the two felts seems to reduce the capillary connection between the two felts enough to prevent ink from being pulled up into the top felt on the 2nd and subsequent refills.

martin0reg said:

PS: and for the scientists among us in post #93 there is a link to the canon cartridge patent, exhaustive reading...

Click to expand...

I can't find the link.

Mikling also has a series of vids at his Precision Colors site and in one of them he draws the ink back from the sponge side into the reservoir using one of the earlier, clear Canon carts.

You can see that there is little ink in the upper sponge and it leaves the upper sponge area pretty quickly. Then as he pumps the ink back in even though you are only talking about a few seconds of time between sucking the ink back and then reversing the process, you can also see the upper sponge somewhat more reluctant to take the ink.

Again when I first saw that vid, I could not relate it to anything I was reading here. But there has been some subsequent posting in this forum by Grandad35 that suppliment Mikling's nicely.

These two guys really make quite a pair as it seems that their data is always dovetailing while not duplicitous.

Grandad35 said:

From my observations:
When refilling, the break between the two felts seems to reduce the capillary connection between the two felts enough to prevent ink from being pulled up into the top felt on the 2nd and subsequent refills.

Click to expand...

This has not been my observation. I tried to keep the upper sponge relatively free of ink alike a new OEM cartridge but eventually the upper sponge will appear, externally, completely saturated on a subsequent refill.

jnug said:

These two guys really make quite a pair as it seems that their data is always dovetailing while not duplicitous.

Click to expand...

Deceitful? To what purpose? It won't sell mikling's stuff any better (as it is already some of the best to be bought) and who knows what the emeritus Grandad35 would gain outside of a kudo.

No, the two lads are just trying to figure things out as best they can, right or wrong.

If their observations seems similar it might be that they have read each others posts, maybe consulted over a PM or two, and are looking at the same finite data set (the cartridge). Reverse engineering is usually simpler that coming up with the product de novo.

Well for example, Mikling has his videos about the carts and how ink moves between the reservoir and the sponge side and Gandad35 had his post where he dissects the fibrous material that makes up the sponge side itself with photos to boot....

It may be just me but I did not understand the interaction between the upper and lower sponge in the PC vids until I saw the post that dissected the upper and lower sponge.

Grandad35 said:

.....I can't find the link.

Click to expand...

The link is in post #93 but in the thread: "Do I have a problem with dry sponges". The link was posted by ThrillaMozilla in this post.

stratman said:

This has not been my observation. I tried to keep the upper sponge relatively free of ink alike a new OEM cartridge but eventually the upper sponge will appear, externally, completely saturated on a subsequent refill.

Click to expand...

The behavior of the top sponge would be expected to be different if the top sponge was still clean. After it gets saturated, does it accept or reject ink on subsequent refills?

BTW - I purposely saturate the top sponge on the first refill, as the cart will supply more ink before emptying. I don't see any harm from doing this, as long as any free ink above the top felt is blown out to prevent dripping.

I was looking at my large carts the other day and I noticed the differences between the old BCl-6 and new BCl-6’s, CLl-8 and CLl-42’s.

I knew about the small channel along the bottom of the carts between the reservoir and sponge section but never noticed this large grove that travels down each side to the outlet sponge.

click to enlarge.
I now intend to replace all of my old BCl-6 carts that don’t have these groves on the sides, if they improved the ink flow with this new design then I don’t see why I shouldn’t take full advantage of it.

Another thing I noticed between the two sponge materials used in the carts is the top sponge is made of a much less dense (Course) material, where as the bottom one is more compact and smoother to the touch. (Finger test).


This is the ---------------------- Top sponge ----------------------------------------Bottom sponge