FLUSHING....WHY?

[CakeHole]

Great series of videos @mikling covers the basics but at the same time explains the ins and outs of what a cartridge is doing and how it works.

 

[martin0reg]

Mikling, thank you for the new videos which are very instructive indeed!
So in future I will refill whenever my canon printer says "low ink" - rather than waiting until "empty"

Beside this now I think to understand also what is my most annoying issue while refilling by german durchstich:
this way you are filling through the sponge into the airtight (!) reservoir and therefore air must be able to come through the vent and sponge and ridges into the reservoir.
Whenever the sponge is blocked (from foam?..or stained ink? ..or what ever) then there is no air exchange and instead of refilling the reservoir ink will be pressed into the upper sponge (then to the vent if you don't stop) .. or it will be pressed out directly through the outlet or the refill hole ..

There COULD be an advantage of this method: you can try to fill a "foamed sponge" by injecting ink in it ... but I can't really say this would work as mostly the only solution for me was indeed: flushing!

 

[mikling]

The other ways to remove these voids that are trapped in the sponge is exactly what remanufacturers of cartridges like HP ice cube types do and that is to flush...which we know about or use a vacuum chamber that can pull down to 26-28inches while having the sponge outlet immersed and inlet shut off and then , slowly release the vacuum. We could get near total filling of the cartridge but the release rate needs to be carefully monitored. The latter is simply impractical to the home person. Even after that, the ink will have permeated into the air labyrinth and you'll need to get it out.

As you've indicated flushing is the only practical way and I think it is.. The last video where I discuss the slow loss of ink capacity is likely lost on some and what its implications are. This loss in ink capacity means that the printhead will have started to slowly becoming starved approaching empty. Each refill cycle it gets worse but it might go unnoticed. Now when we think back about the Pro9000....we know that PM is used a lot and if one tops off all tanks when the time comes to refill, then the only candidate to have the starvation effect will be the first one to empty....many but not all the time it is PM. Might this be the causative factor in some printhead failures in the PM channel.....the slow loss in capacity and mistaken belief that if the reservoir is full, the printer is well fed.

One aspect of the Canon cartridge that no one has ever brought up is why did the engineers create an increasing density towards the bottom (wedge) and also ever notice the straight vertical change in density directly above the outlet? What functions does increased density of the fibers serve? Is it a filtering process of some type that is not necessarily for solids?
What does increased density of fibers do relative to one that is less dense?

 

[mikling]

One other aspect of refilling that has also unnnoticed is at what rate the replenishment of the sponge takes place. You german refillers never picked up on this. In the second video notice the low rate of filling. What effect does that serve? What happens when you do it quickly?

You'll come to see the relevance of the variable density as well the rate of refill in how it can affect the quality of refill. These were all variables in trying to understand why some people need to flush and others don't. It was never the ink story as some would have you believe.....

As you can see I like to make people think. These simple ink carts are highly engineered.

 

[stratman]

One aspect of the Canon cartridge that no one has ever brought up is why did the engineers create an increasing density towards the bottom (wedge) and also ever notice the straight vertical change in density directly above the outlet? What functions does increased density of the fibers serve? Is it a filtering process of some type that is not necessarily for solids?
What does increased density of fibers do relative to one that is less dense?

I'm pretty sure the topic of variable sponge density has come up before. What this may import would, intuitively, be rate control of ink flow.

Do you have a better theory?

 

[mikling]

I'm not sure of the rate control because if you look carefully or take one of the cartridges apart, right above the outlet there is a curved distortion in the wall. It allows the density to decrease going up! If it was to control flow rate it would have had to be uniform or consistent right to the outlet.
The flared portion going up with decreased density I think acts like a drain pipe. The density going towards the bottom gets higher as that will increase the saturation level of the sponge as the sponge empties. This is then easier to drain out to the outlet via flare due to the curvature of the wall. In other words, the increased density towards the bottom ensures that there will be less air voids all the way to the bottom and it is easier to keep the denser portion saturated. This will provide better ink conduction/creep properties so that the outlet is well fed. To allow the outlet to get more exposure to these saturated areas, they flare the walls and decrease the density vertically a little bit.

Now as to the refill rate. I understand that with many german refillers, they fill the reservoir, let it stand and then refill a bit again. That allows the sponge to be resaturated at its natural rate. This then allows the incoming ink to lift or to push the air voids/bubbles up. Remember that with the German method it will only resaturate at the natural rate. Similarly, if one top fills and slowly puts the ink back in, they'll be able to possibly achieve the same effect. If you refill the reservoir too quickly, there is possibility of ink spreading over the air voids and trapping them. Most topfillers will not have the same patience to refill a cart in minutes or even one minute. Many just instantly fill the reservoir and then this pressure from the ink head forces ink into the sponge faster than it would naturally wick and this covers the air voids...traps them and compromises sponge capacity.

So is this advantageous to use the German method....the only issue is that many refillers will not have the patience and the most difficult part is refilling when the tank is partially full and the sponge is fully saturated. If one develops the knack or skill, then it could be advantageous but many have tried and failed to do it properly.

What seems important though is that there exists a time element. The fastest is to refill at low and refill the reservoir as fast as you want. This does not allow the sponge to change its condition much. Any other method will require patience.....and testing of will.

 

[stratman]

I'm not sure of the rate control because if you look carefully or take one of the cartridges apart, right above the outlet there is a curved distortion in the wall. It allows the density to decrease going up! If it was to control flow rate it would have had to be uniform or consistent right to the outlet.
The flared portion going up with decreased density I think acts like a drain pipe. The density going towards the bottom gets higher as that will increase the saturation level of the sponge as the sponge empties. This is then easier to drain out to the outlet via flare due to the curvature of the wall. In other words, the increased density towards the bottom ensures that there will be less air voids all the way to the bottom and it is easier to keep the denser portion saturated. This will provide better ink conduction/creep properties so that the outlet is well fed. To allow the outlet to get more exposure to these saturated areas, they flare the walls and decrease the density vertically a little bit.

I think you described rate control of ink flow such as what happens to a column of fluid in variable porous membranes. The wetting resistance and gas permeability of the "sponges" determining, in part, how ink flows and is thereby controlled. However, without the negative pressure exerted by the print head on that column of ink then no flow, or sustained flow, would be possible.

Similarly, if one top fills and slowly puts the ink back in, they'll be able to possibly achieve the same effect. If you refill the reservoir too quickly, there is possibility of ink spreading over the air voids and trapping them. Most topfillers will not have the same patience to refill a cart in minutes or even one minute. Many just instantly fill the reservoir and then this pressure from the ink head forces ink into the sponge faster than it would naturally wick and this covers the air voids...traps them and compromises sponge capacity.

What seems important though is that there exists a time element. The fastest is to refill at low and refill the reservoir as fast as you want. This does not allow the sponge to change its condition much. Any other method will require patience.....and testing of will.

This is very interesting. Simple yet elegant, mikling.

Does this malfunction exist with other sponge/filter devices such as water filtration systems?

Is it possible the ionic forces within the sponges exert an effect on ink flow or saturation?

Is there any effect of ink solutes on the sponges?

 

[The Hat]

I think it’s great to be discussing the refilling procedures of the Canon cartridges in a big way once again. (I must get out more)

If you look at the discussions and refilling techniques that were been used back when Adam was a boy, the refilling side haven’t change that much but our understanding of it certainly has.

I as a constant refiller have done it all and have worn the tee shirt but have I really ? but just like most refillers I imagine or think I know it all, Ops.

Like the way Yello Jello syndrome and the 551 cartridges hit us right in our comfort zone and we immediately began to circle the wagons thinking all was lost because we had gotten too comfortable in our own ignorance.

It must have given Canon Techies a bloody good laugh watching us all reeling from the shock and horror of not been able to refill the newest and most popular cartridges anymore.

I bet there are guys out there right now; who think this is all totally unnecessary because their refilling technique is so perfect they don’t need a refresher course.

So come on guys get your thinking caps on and get involved in this thread, if not for your sake then do it for others please ask the questions, give us your opinions and get the right answers..

 

[stratman]

I bet there are guys out there right now; who think this is all totally unnecessary because their refilling technique is so perfect they don’t need a refresher course.

I love this stuff.

Just like Science, nothing is written in stone. Consensus does not confer immutability. Mikling has proffered something intriguing and exciting that wags the tail of the dogma.

 

[ThrillaMozilla]

Mike, I think your explanation is right on the mark. I had wondered why people had success, considering how easily air can fill the sponge.

I'm pretty sure flushing is not the only way to remove air. That's why I still use GHWellsJr's Freedom Fill method, which makes it quite easy to get rid of the air in the sponge with just a syringe and a simple adapter. As a shameless advertisement, here is the very simple syringe adapter that I use, and here are the fine points that I think are necessary. It's quite easy, but it's a bit time-consuming and not for everyone.

The other ways to remove these voids that are trapped in the sponge is exactly what remanufacturers of cartridges like HP ice cube types do and that is to flush...which we know about or use a vacuum chamber that can pull down to 26-28inches while having the sponge outlet immersed and inlet shut off and then , slowly release the vacuum. We could get near total filling of the cartridge but the release rate needs to be carefully monitored. The latter is simply impractical to the home person. Even after that, the ink will have permeated into the air labyrinth and you'll need to get it out.

I'm not sure what you mean by this. First, you don't need an amazing vacuum pump. You can easily get almost all the air out by repeated strokes with a syringe. For example, if there are 10 mL of air in the cartridge, expanding it twice to 50 mL and replacing it with ink each time leaves only 4% of the air in the cartridge. I don't usually expand it that much each time, but my own guidelines call for three strokes. I find that's about right to avoid getting air in the vent. I also find that I don't have to release the vacuum especially slowly, but I do have to be careful not to release it so fast as to move the sponge. It's not perfect (I recently had some evidence of a little ink starvation), but I have had pretty good success with it.

Incidentally, you show one picture with an empty sponge but a full reservoir. It would have been interesting to tap the cartridge to dislodge any bubbles between the chambers. I have had that condition with an older type of (HP) cartridge (which I no longer use). A few taps immediate initiates a flow of bubbles into the reservoir until the sponge is saturated again. You previously mentioned that Canon had made a change in the ink bridge to prevent this condition, and I suspect that HP did also.