FLUSHING....WHY?

[fotofreek]

My habit has been to check all carts when one shows low or empty. I then replace not only the low or empty cart but others that are somewhat low as well. What I want to avoid is the scenario in which I would replace one cart, have the printer automatically run the cleaning routine (in which all carts lose some ink) and have one of the previously somewhat low carts now show low or empty after just a few prints. In the long run I believe that I lose less ink and gain more printing time as there are less numbers of cleaning routines. I haven't done the math, but I think this routine is better than just replacing the cart that shows low or empty.

If I were using new factory filled OEM carts instead of refilling I'd then try to use as much ink as possible before changing a cart. Because the ink is so inexpensive for refilling I'm not concerned about wasting a bit of ink now and then. Even when I refill a cart and, when testing it, find that the ink flow is not great I have no problem wasting a cart full of ink to purge the cart and restore its ability to have really good ink flow.

 

[stratman]

I used to run the carts to empty to minimize the waste ink pumped into the pads, and kept detailed records of the number of "equivalent 8x10" pages printed/cart. The PM carts averaged 30-35 pages to "low". plus an additional 3-4 pages to "empty". From this data, you get an additional 10% of ink from the bottom sponge after the ink chamber is empty and therefore reduce the life of the purge pads by about the same 10% by refilling on "low".

Some interesting data. Thank you. I take it you reference the PM cartridge because they are the first to be used up? Or are the PM cartridges the most problematic in your drip test?

When I "ran to empty", this was definitely not the case, and there were many times when I had extended troubleshooting sequences which I now believe to have been caused by cart starvation.

That certainly would be motivation to change your refilling strategy. Glad to hear those troubles are a thing of the past.

Why not just start with a clean cart each time and purge after one refill? Because I am retired and don't like doing any more than is necessary. Also, there is a lot of unrecoverable ink left in a cart when it is purged. It may not end up in the purge pads, but it is still lost.

Not what I was trying to convey. I was thinking why not use the cartridges until a problem exists. But, given your statement that you had problems with freshly refilled cartridges after one time then I understand your reluctance to change your current strategy.

What I do not understand is how a newly purged or first time refill on a new and never purged cartridge could fail? The purged cartridge may be due to improper purging -- separated sponges -- or a bone dry sponge that needs time to absorb the ink. But the new, refilled first time cartridge should not fail unless there is something odd.

That's what the manual says, but how does it know that a cart has been removed and replaced...

This is out of my wheelhouse but I would think it has something to do with electricity. My printer has a solid red light when a properly chipped cartridge is installed and has sufficient ink. This light then instructs the user to which cartridge is empty by flashing on/off. When you take the cartridge out, something happens electronically to the loss of contact with the cartridges electronics. This may behave a a simple switch for all I know. Hence, the printer records the removal of a cartridge and then does a maintenance purge when same/a cartridge is (re)installed.

What would happen if the power was off or the power plug was pulled from the electrical outlet? It may be that there is a residual current draw on the printers even when shut off that is enough that if you were able to bring the print head carriage out away from the parked position over the purge pads that the printer would "know" that a cartridge was taken out. The printer would definitely not know this if the plug was pulled or the power and you could take out the print head or any cartridge, reinstall, reposition the print head in the parked position, turn on the power and the printer would be none the wiser.

It does behoove Canon to be able to determine a cartridge has been removed from the print head in order to make sure the "new" cartridge has had sufficient ink drawn out to ensure proper functioning (no air in the print head and the sponge is nice and primed with ink for printing).

 

[stratman]

My habit has been to check all carts when one shows low or empty. I then replace not only the low or empty cart but others that are somewhat low as well. What I want to avoid is the scenario in which I would replace one cart, have the printer automatically run the cleaning routine (in which all carts lose some ink) and have one of the previously somewhat low carts now show low or empty after just a few prints. In the long run I believe that I lose less ink and gain more printing time as there are less numbers of cleaning routines. I haven't done the math, but I think this routine is better than just replacing the cart that shows low or empty.

It is like we are twin sons of different mothers, though I wait till one cartridge is marked Empty.

 

[stratman]

Considering this air in the sponge issue as real, the air may be the symptom and not the cause of the problem.

Granted that the air in the sponge occurs as ink is used up. But why does the air remain instead of being supplanted by ink? After all, Canon went through a lot of money and research to figure out the proper balance of retaining ink versus allowing the ink to flow out of the sponge smoothly on demand.

This ties in with why purging helps and Pharmacist's solution helps.

The root of this issue may be due to changes in the charge of the sponge during usage as ink flows out. Is this static electricity caused by the flow of ink or air in the sponge? Is this a difference in the ionic nature between OEM ink and aftermarket ink?

Whatever contribution the air has in Mikling's hypothesis, It may be more than the presence of air that creates the condition for the air to be an issue.

 

[The Hat]

@stratman has his professor hat on and is trying to confuse the hell out of me again.

It’s certainly a good theory and one that might spark more investigation, and as you say there’s more to these pesky little cartridges than meets the eye..

 

[Grandad35]

….I take it you reference the PM cartridge because they are the first to be used up? Or are the PM cartridges the most problematic in your drip test?

Both, with the PC carts a close second. As I have written previously, I seldom have to purge the other carts, making one wonder if there is a relationship between never running “low” and not requiring purging. There are a number of members on this forum who report never having to purge, and there are also a number who refill before their carts run “low”. Is there a correlation?

What I do not understand is how a newly purged or first time refill on a new and never purged cartridge could fail?

Sorry if I wasn’t clear. I have never had a failure on a fresh cart, but if a fresh cart is allowed to run to “empty” I have had a failure on the 2nd fill (not often, but it has happened).

My printer has a solid red light when a properly chipped cartridge is installed and has sufficient ink…..

This is a generational problem – my i9900s don’t have chipped carts, and no signal is sent to the mother board until the carriage goes home and the (single) sensor looks at the prisms of all 8 carts. With chips, your printer has the ability to immediately sense when you remove a cart.

Considering this air in the sponge issue as real, the air may be the symptom and not the cause of the problem.

Granted that the air in the sponge occurs as ink is used up. But why does the air remain instead of being supplanted by ink? After all, Canon went through a lot of money and research to figure out the proper balance of retaining ink versus allowing the ink to flow out of the sponge smoothly on demand.

Here’s my simplified (and unproven) hypothesis.
The foam in these “sponges” is an open cell foam that allows the ink to completely fill the cells and form a continuous "ink link" from the ink chamber to the exit port. The surface energy of purged and dried foam is such that the ink wets out on the foam and pulls itself into every nook and cranny. What happens when the ink is withdrawn - here comes the conjecture:

1. Because the nozzles are so small, they can generate a sizable suction on the ink (proportional to the ink's surface tension divided by the nozzle diameter - several psi).
2. Pulling the ink out of a cell and replacing it with air also requires suction, but since the sponge's cells are much larger than the nozzles, this suction is much lower than what the nozzles provide. This is why the nozzles can pull ink out of the sponge.
3. When the ink is removed, a film of ink seals off the openings in the cell, much like a soap bubble. This film is fairly weak, allowing single bubbles of air to break through as required as the sponge empties.
4. On subsequent refills, the sponge is now completely coated with ink, so the surface energy is now the same as the ink; there is no driving force to pull the ink into the sponge as there was on the first fill. Is this a design flaw by Canon? On the contrary, it is a design feature that makes refilling more difficult - their only concern is for the cart to work once.
   
5. Even if you put pressure on the ink chamber to push ink into the air pockets in the sponge, you are fighting all of those "soap bubbles" that don't want to be broken, and it is easier for the ink to be pushed up along the sides of the sponge to the top of the sponge chamber (causing a drip until this ink is removed).
6. Purging and drying removes the liquid from the sponge, restoring the surface energy to get a near perfect initial fill.

I first started to dig into this subject a number of years ago when I tried vacuum refilling. This worked, but my method was way too messy to be practical for home use. Note that I have changed my thinking on some of these points over time, so if you catch some inconsistencies between then and now, go easy. Later, @ghwellshr developed his "freedom refill" method which addressed many of my problems.

 

[martin0reg]

....
...my special problem as I wanted to reanimate an old ip4000 and I only have empty BCI's not used for quite a while. Some were flushed some not...trouble began as nearly all of these would not take ink into the reservoir - while the sponge side would easily overflow (see my postings from #31 to #53).

For now I think if you want to flush and then refill an empty BCI cartridge you have to take care of the following (beside other well known points)
- flush without any cleaning solutions which are prone to foam building .. use only water, at least for the last flush use distilled water (for cleaning or conditioning you might try pharmacist's solution)
- if refilling "german": seal the air vent - to avoid sucking the ink too fast and too much into the upper sponge. (what might be the most important advice as I never heard of it before...)
- inject very slowly and be aware of the sponge side sucking too fast and/or too much...in this case you can try blowing into the vent to get rid of faom in the sponge. If nothing helps start again with flushing...

After I have flushed some more of my old BCI (either dried out or refilled without success, bad ink flow) I have learned something more about foam and air blocking..

I use to flush "german" injecting water through the sponge (like refilling "german"...yes I know it would be easier through the top hole, but my carts don't have this yet..)

First I overflow reservoir and sponge with water or conditioner several times, then blow out the water through the outlet by blowing into the vent. Blowing out the liquid out of the sponge side should empty also the reservoir - if the cart is working properly meaning the fluid in the reservoir is sucked into the sponge while doing so.

Now it can happen that
- foam instead of liquid is coming out of the outlet: bad sign because this foam in the sponge would build up also when refilling ink- continue with flushing/overflowing...
- blowing in the vent hole is hard to do: bad sign because the sponge side seems to be blocked, also no fluid is sucked from full reservoir into the sponge - continue with flushing and let the conditioner stay a while in fully filled cart to dissolve the blocking in the sponge.

So accurate flushing of a problem card is as important as careful refilling - at least with my old BCI carts...refilling carts which are in daily use may be easier to do..

PS: grandad35 hypothesis about foam building and blocking sounds plausible...I am thinking how it relates to my "problem carts"...especially points 4-5-6...

 

[PeterBJ]

Not everybody needs to flush the cartridges regularly. See this thread by @jimbo123 . But jimbo123 is refilling the PGI-5/CLI-8 cartridges, not the BCI-3e/6 that might be more difficult to refill. I don't think that Canon introduced the groove at the bottom of the PGI-5/CLI-8 cartridges to make them more refill friendly, so it must be to solve a problem with the BCI-3e/6 cartridges. I don't know which problem.

Note that jimbo 123 refills before the reservoir is empty, thereby reducing or eliminating the risk of the sponge absorbing air, so it seems that early refilling is a good idea. I think this makes mikling's theory very plausible.

 

[The Hat]

I got to hand it to you @martinoreg you certainly go to an awful lot of trouble to get your cartridges working properly again.

But would it not be easier to pop the plastic ball in the top of the cartridge to help you when you want to purge a cartridge, it would be so much quicker, you could refit the ball afterwards and tape over the hole to seal it up again.

You can get a roll of 3M Aluminium tape in your local Lidl supermarket.
My two cent worth..

 

[CakeHole]

Or just make/buy a cheap flush clip.