Do I have a problem with dry sponges

mikling said:
I added some comments on the pics so I will upload again.

PICS with inserted comments

http://www.mediafire.com/file/4gd9p96584q0zvh/Sponges and tanks with comments.rar
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Great post!

A most interesting and rewarding test. You have managed to answer several questions - the top sponge may look saturated but is/may not be at all, there is/may be a wide latitude for where the Durchstich refill hole may be located, and structural changes between BCI and CLI cartridges are/may be the reason for ghwellsjr's misfortune with the Durchstich method.

You have left us with a cliffhanger ending concerning both how Canon fills their cartridges and what the structural differences are between BCI and CLI cartridges. I'll stay tuned to this Bat-channel for the next episode of Mikling's adventures in printing.

(Bat-channel = 1960's reference to the TV series "Batman".)
 
The mess in your testing photos is how some of my normal refills look like. Amazing that the fully soaked top sponge was still white inside. You did a great job in demystifying the inside workings of a cartridge mate. Thanks Mike.
 
martin0reg said:
@ghwells
I use also blunt needles (hole above bottom). To get over the ridge I just press the syringe a little bit up to get the needle away from the bottom. It is like poking with a picklock.
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That's probably the same as what I do. I called it flexing the needle up and down until it goes in but I couldn't get that to work when I put the hole above the PP. What cartridges are you refilling?

Where does your needle contact the bottom of the cartridge? Before or after the ink outlet hole?
 
@ghwells
If you tried to flex it already, flex it more or less. Sounds annoying and the ridge certainly can be.
Pierced in a hole above the bottom leading down to the "ink tunnel" the needle should contact the bottom near the tunnel, or better not at all, so it goes straight into it. But I have to poke and flex sometimes too...


stratman said:
...
The two factors I believe usually responsible for requiring a flush are a stiff sponge from cake ink or other particulates, and, a blocked air vent from ink. It is not clear to me that a sponge colored/saturated with ink - while not blocking the air vent itself - is a culprit in ink starvation..
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I think caked or dry ink in the upper sponge could block the air exchange - not in the air vent but at the "ink tunnel". The air exchanges through the vent AND through the upper sponge to the grooves in the wall leading to the "ink tunnel".
A colored or even saturated upper sponge may be okay - as long as the ink will leave it down to the lower sponge (miklings new pictures are showing this).
I have sometimes this special issue: while injecting (german durchstich) in the ink chamber the ink in the sponge chamber goes rapidly up to the top and it is impossible to continue without pressing the ink in the air vent. Looks like a slowly ""ink explosion" in the sponge chamber. Reason is: no air exchange to the ink chamber. My explanation: caked or dry ink in the upper sponge and therefor no breathing..

@mikling
Thank you for the annotations to your vivisection of a canon cartridge.
Seems to be a private class of fluid dynamics here in this thread

My guesswork regarding the last two pictures: If a sponge or paper towel is in contact with the fluid in the ink chamber, it will suck it out. But there has to be air exchange though the same hole ... ?
If I drink beer out of the bottle it gurgles...
 
Mikling,

Great work and presentation!!! You have certainly backed up your statements with proof. Everything that you have shown can be explained by surface energy/surface tension.

Questions:
1. Did you also slice open the bottom sponge to see if it was completely saturated?
2. It took 9 ml of ink in the sponges to get the cart to drip. Could you measure the volume of the sponge chamber (up to the top of the sponges) without the sponges to get an idea of the total degree of fill in the sponges? Alternatively, you could weigh each sponge after filling and estimate their maximum capacity by measuring them and calculating their volume.

I still use the "top fill" method, and use a variety of carts - only about 25% of them are OEM (GASP!). My i9900 (x3) has 8 colors, and I have 45 carts used in rotation. My carts are stored in food containers with a paper towel in the bottom that is soaked with iso-propyl alcohol. This prevents drying or bacterial growth in the sponges or filter. It also makes them feel "wet" when removed from the container, so they must be wiped down with a paper towel when removing them from their storage clips. I also blow into the top vent port to cause several drops of ink to flow from the exit (catching the ink in the paper towel, of course) before installing them in the printer to make sure that there is an "ink link" to the exit filter, making it easier for the printer to prime the new carts.

I purposely completely fill the sponges (Double GASP!) to print the maximum volume of ink from each cart, as this minimizes the number of cart changes, and therefore the amount of ink pumped into the waste tank. As your photos clearly show, the printer uses the ink in the top sponge before it starts to draw from the tank, so more ink in the top sponge is a true increase in the useable capacity. After they are refilled, I wash them under the faucet and then blow into the vent port to blow out 0.5-1 CC of ink to remove any excess ink that might have worked its way above the top sponge to prevent drips. This procedure isnt for everyone, but it works for me. No I have never dyed my lips; thats why they carts are washed first.

Why doesnt Canon fill the top sponge? Could it simply be because this would increase the useable ink/cart and therefore reduce their cart sales rather than for a technical reason?

I look forward to seeing your photos of the change in the CLI-8 carts.
 
Grandad35 said:
Why doesnt Canon fill the top sponge? Could it simply be because this would increase the useable ink/cart and therefore reduce their cart sales rather than for a technical reason?
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Perhaps because it allows them to fill more cartridges at the same time.

The time required for the upper sponge to appear fully soaked is probably not worth the advantage of a minority of customers thinking they are getting a better deal.
 
Grandad35 said:
Why doesnt Canon fill the top sponge? Could it simply be because this would increase the useable ink/cart and therefore reduce their cart sales rather than for a technical reason?
Click to expand...
If Canon wanted to increase their cart sales they could just reduce the size of their carts, which is what they are now doing for that reason.

If you look at their original cart design of the BCI-3 series that had only one large sponge in it (see a picture of it on post #47) and realize that they changed the design to have two different sponge materials in the BCI-3e series, I think you will see that they were concerned about the air flow from the top sponge down to the top of the groves along the wall separating the two chambers.

Now that mikling has disclosed the fact that the inside of the upper sponge can remain dry, it is obvious that they do that for air flow. When you handle one of these sponges, you can feel that it has a different density on the inside. It feels like there is a sheet of something rigid inside it.

After all these years, somebody finally actually took a look inside the upper sponge material, thanks mikling.
 
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