FLUSHING....WHY?

[martin0reg]

@The Hat and CakeHole, flushing could be easier through the top hole and with a flush clip and I thought of both things already..
..BUT the "german" flushing with overflowing and blowing out the fluid is not so hard to do, IF the sponges are working properly...!
While flushing this way you will find out which are the problem cards and can repeat flushing or soaking them - before drying and refilling without success...

Anyway with my next order I will buy flush clips and silicone plugs and remove some balls.

 

[mikling]

It's finally here, we seem to getting to a plausible theory and how to do it properly after many many years. I religiously tend to refill my carts before they empty or even get low most of the time and hardly really needed to flush. For my relatives that I support and they are not religious about refilling early whatsoever, flushing has been required. So there appeared to be a correlations that I did not pick up earlier.

The question is then raised...if the regimen to refill before the reservoir is empty, can this eliminate flushing.... My answer at this time and it could change is no. Once or maybe twice...I had to flush carts that had hardly been used.....but was stored for a long time. Aging of ink might have something to do with it.....experimenting to prove or disprove this would be near impossible due to time.

Grandad has been instrumental because he keeps track of his practices and makes observations.

The humiliating aspect to all of this is that as I had written before, the issues are well known in integrated printhead cartridges which are only different in that they start use with an empty reservoir and beyond that perform similarly to the systems under discussion. Had we paid attention to this before, the flushing issue might/could have been understood earlier.

As to the empty reservoir, and low ink warning timing, it is not as clear cut as many would think. Subsequent to these findings I am running more detailed observations on the low warning behavior. I have had one new OEM CLI-8 report a low warning even though the reservoir was not empty. This indicated that the chip count can override the optical sensor in certain situations. It only illustrates very well that if the chip feels that the low point should have been reached and it has not, it will proceed with the low point and advance the counter.

This logic backs up my theory on the chips having two separate counters. Once the low warning is triggered either by physical detection or chip count, the chip moves to another counter and begins the countdown to empty. I presented this on discussing what happens to CLI-42 chips that had been disabled and subsequently reset. That theory still works and I have not found anything to indicate it is flawed yet but it is a theory based on observation and subject to changes as evidence presents itself.

As to the newer cartridges, like the 226/221 etc and 251/551 etc. I have definitely observed that the ink reservoir will be empty but the low ink warning will not be issued as yet. My theory is that with the smaller reservoirs especially on carts line the 251 non XL, Canon cannot / will not throw out a low ink warning right after the prism detect because it would be too soon. There is actually more than 50% left in the 251 non XL when the prism will no longer detect ink....consumer reaction would be not good. Over the years, Canon has gained more experience in ink estimation and possibly run the warning based on % of total capacity left and their ability to track it independent of the prism is possibly improved over the earlier years.

On the 9500 and Pro-10 it tracks very well even without ink sensors. Is it a case that sponge systems are much more variable and subject to a host of factors yet uncovered?

 

[Grandad35]

The humiliating aspect to all of this is that as I had written before, the issues are well known in integrated printhead cartridges which are only different in that they start use with an empty reservoir and beyond that perform similarly to the systems under discussion. Had we paid attention to this before, the flushing issue might/could have been understood earlier.

Taking this one step further, I remember how I was able to revive some of the old HP 56/57 carts using a "tube sock centrifuge" to force ink into the sponge. I only have one cart in my "to be purged" container at this time, but I gave it a quick try, filling the ink chamber to about 50% before starting. The test was terminated when it was obvious that satisfying my intellectual curiosity wasn't worth getting an even bigger blister and a sore shoulder. Even with a short (20 seconds or so) test, the sponge next to the ink chamber was now well saturated, and the cart's drip test was better than it was before the centrifuge, even if it still failed. I leave it to someone with young joints or a centrifuge to do a proper test. I closed the refill hole and placed the cart in a clip to prevent ink from leaking out the bottom, but I would also like to see the results with the refill home left open - I suspect that the results would be better, especially if the G-load and time could be increased.

 

[The Hat]

I run a 521/520 small cartridge printer with CLI-8 carts fitted and apart from the initial fumbling with the low ink warning system, when printer was detecting something was wrong.

Now the printer accepts the larger capacity carts as if they were the normal small ones and I only get the low ink warning when the reservoir becomes empty.

There are lots of different thing happening with the OEM cartridge chips and nothing should be taken for granted with them, especially the CLI-42’s, can the EPROM chip reprogram these cart chips ?

 

[stratman]

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:

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.​

​

Point #4 is interesting.

Could surface charge be in play here? What are the roles of the charges of the ink and sponge? Could it be the charge of the refill inks is different than OEM inks and therefore create issues with either ink absorption or ink starvation?

I see how a flush of the cartridge with water under pressure would remove your scenario of a film of ink that allows air bubble to create a block to absorption of ink during a refill, but how does using Pharmacist's solution restore a bone dry cartridge that resists ink absorption in the sponge to "normal" absorption? Surface energy, surface charge, something else? For that matter, why would a bone dry sponge, one that has no ink film, result in a problematic ink absorption?

 

[stratman]

Not everybody needs to flush the cartridges regularly. See this thread by @jimbo123 .

Umm, I also do not purge and haven't for years. Maybe the CLI-8 cartridges were the best design for us refillers.

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.

I do not refill (Durchstitch method using squeeze bottles and 2" blunt needles) until one cartridge is marked as empty. Then I will refill others based upon their fill levels, usually if their spongeless sides are already empty or near empty. While this may fit the mikling hypothesis, it also means that the already empty spongeless cartridges have had air in the sponges and should mean that by waiting to refill till after using some of the sponged ink up and thereby creating foam in the sponges,over time, my cartridges should display the air bubble issue on refilling. Given that some on this forum have stated the air bubble phenomenon may occur quickly, why do I not experience over several years time?

Could it be I do not print enough in a single session? Yet, the mikling hypothesis has been said to demonstrate missing ink with first printed page and not just after sustained printing. This clearly is not happening to me.

I do not print every day and it may be once a week for a handful of pages that may not use all the colors or even most of the page (receipts from bill paying). Sometimes I will print a number of images or tens of pages of documents. I have gone more than a week without printing on occasion. I use only one set of cartridges for years, with these cartridges being several years old (except for the current PGI-5 which I found tucked away in storage recently). The room the printer sits in does not have air conditioning and is basically whatever the humidity is of the outside, and mostly receives heat from whatever is created by the sun or whatever flows in from the room next door. I will use baseboard heating in the winter when in the room, but otherwise, the heat is off.

In other words, the environment and use conditions are far from controlled or optimal. Yet the cartridges keep working. Why am I an outlier? This is why I am not entirely convinced of mikling's theory yet. It is intriguing. It may be more representative of other cartridge models. It may be the holy grail for any and all cartridge (does that include the PGI-9 that is refilled by drip method???). I need time and more info to digest for a while.

 

[stratman]

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..

I agree. It would be easier to make a top hole, either by your suggestion or by drilling a 2mm hole near the ball area, and then securing it with a silicone plug. Then he would be able to generate more pressure in his flush to complete the job faster.

But this is the personal part of refilling that lets each of us express ourselves uniquely. As entrepreneur Martha Stewart says, that's a good thing.

 

[stratman]

There are lots of different thing happening with the OEM cartridge chips and nothing should be taken for granted with them, especially the CLI-42’s, can the EPROM chip reprogram these cart chips ?

Do not understand. Please explain further.

 

[stratman]

It's finally here, we seem to getting to a plausible theory and how to do it properly after many many years. I religiously tend to refill my carts before they empty or even get low most of the time and hardly really needed to flush. For my relatives that I support and they are not religious about refilling early whatsoever, flushing has been required. So there appeared to be a correlations that I did not pick up earlier.

Are you accounting for differences in printing use and environmental conditions?

Do you provide them with more than one set of cartridges such that they store these cartridges until needed? Stored cartridges could lead to thickening or drying out of ink and/or sponges. How are you accounting for any differences with these stored cartridges?

the issues are well known in integrated printhead cartridges

Not to me. Please explain.

I have had one new OEM CLI-8 report a low warning even though the reservoir was not empty. This indicated that the chip count can override the optical sensor in certain situations.

Or, that the optical sensor was not functioning as you expected. Without additional information I cannot conclude it was the chip that triggered the Low warning.

As to the newer cartridges, like the 226/221 etc and 251/551 etc. I have definitely observed that the ink reservoir will be empty but the low ink warning will not be issued as yet. My theory is that with the smaller reservoirs especially on carts line the 251 non XL, Canon cannot / will not throw out a low ink warning right after the prism detect because it would be too soon. There is actually more than 50% left in the 251 non XL when the prism will no longer detect ink....consumer reaction would be not good.

Consumer reaction? What about Canon's shareholder reactions when they learn of potential waste of money used to continue to manufacturer cartridges with unnecessary optical sensors? Yes, the optical sensor would be important if a cartridge were to leak ink from the spngeless side. But how often does that occur with a new OEM cartridge? And would the warranty costs exceed the costs of continuing to use optical sensors?

The Low ink warning is to condition the end user to buy more ink for the inevitable replacing of the cartridge go buy a new one soon. It is not a warning that means "replace cartridge now!". While I comprehend the psychology you infer, end users would eventually get used to the rate at which the Low warning occurs once they see the pattern of progression from Low to Empty. Heck, it might even drive the end user to purchase the spiffy XL sized cartridges. Win-win!

 

[Grandad35]

Could surface charge be in play here? What are the roles of the charges of the ink and sponge? Could it be the charge of the refill inks is different than OEM inks and therefore create issues with either ink absorption or ink starvation?

Without getting too complicated, here goes my conjecture:

1. Using an electrostatic charge to pin films has been around for a long time. The voltages involved are usually in the range of 20,000 volts and will throw a spark about 1/4". It's hard to envision generating that kind of voltage inside an ink cartridge, so the forces will be small. Even at 20,000 volts, we are talking less than 20 grams of force across 10 sq cm (from 10 year old memory), and the force drops off rapidly as the voltage is reduced.
   
2. Charging solid particles in air (e.g. powder coating) creates a very weak force because of the low field strength (voltage/distance) - the powder particles slowly drift to the item to be coated, they don't snap to them. This level of force is hardly sufficient to pull ink into a foam cell.
   
3. The uses that require higher forces apply the voltage over a much shorter distance (1/2" in the case of edge pinners), and involve a charging area and a ground area to create a controlled field. How is the field generated in a cart?
   
4. Since the "sponge" is an open cell foam, all of the ink is connected, and applying a charge in one area of the sponge will apply the charge uniformly through the ink. This effectively "shorts out" any attempt at creating a field across a cell wall.

For that matter, why would a bone dry sponge, one that has no ink film, result in a problematic ink absorption?

I experienced this problem twice - on the same day. After further tests, I suspect that the problematic carts were not completely dry on their first fill. During my last purge cycle (I finished purging the batch that I bought on eBay a while ago) , I weighed each cart after they were blown out with compressed air. Most of them weighed about a gram more than a dried cart, but a few weighed as much as 4 grams more. I found that how I held the compressed air nozzle to the refill hole had everything to do with how well the water was blown out, and that re-blowing the heavy carts brought their weight down to normal. The problematic carts had been air dried in my basement for a few weeks, and I just assumed that they were dry. My guess is that these carts weren't blown out properly and weren't dry when I first tried to fill them, and the water in the cells changed the surface energy of the foam.

In any case, my procedure is to now weigh each cart after blow-down and again before they are put into storage as "dried".