Important : Canon Pro-100 Cli-42 Yellow Ink

mikling said:

The PC42-Y ink is made by IS and sold to normal refillers under another number.

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What about the rest of us who aren't normal refillers?

I meant to say the remanufacturers and refill shops!

Mike,

Have been staring at the wording from your final two sentences in the message above for some hours, and am still confused. Not knocking your work, I am just not sure what is being said.

Have reproduced the paragraph below and reading the final two sentences (Now in bold) you seem to be saying that the same yellow compatibility problem exists with the 9000ii PC inks and the CLI-8 carts.

If I am reading that correctly, then how will changing the 42 chip to a CLI-8 cart overcome the problem?

I must be missing something in translation, but the language is somewhat ambiguous.

Can you clarify for dimwits like me?

The PC42-Y ink is made by IS and sold to normal refillers under another number. It is more widely used than the yellow ink in the Pro-9000 and on other CLI-8 Y and has been used for over ten years by millions of users. So this PC42-Y is not a new ink. I selected it to because it met the physical requirements of the printhead and its color more closely matched the color of the CLI-42 Y than what was used on the Pro9000. The ink used on the Pro9000 has identical issues as seen on the PC42-Y. So
there appears no easy solution to this or else I would have taken that route.

Roy

I think the problem is caused by the CLI-42Y OEM ink, and not the refill inks as the gelling can also be caused by water. This means that many refill inks could cause the gelling reaction, as the refill inks are probably close to neutral pH.

From high school biochemistry I remember that the isoelectric point of a protein like for instance gelatin is the pH value at which the solubility in water is least. The isolectric point was determined by titration using a pH meter.

I think this could be an explanation: The CLI-42Y OEM ink is probably made more alkaline or acidic than the isoelectric point to keep the gelatin(?) in solution. When diluting the OEM ink by refilling with a refill ink that is close to neutral or by flushing with water, at some dilution the isoelectric point is reached and the gelatin(?) precipitates.

There seems to be two types of gelatin, one with an alkaline and one with an acidic isoelectric point. See this: http://www.sammi-gelatin.com/em2.html

Maybe someone with access to the necessary lab equipment could test this hypothesis?

Excellent reasoning PeterBJ. Interesting, could this be a way of discouraging re-fillers?

The note that "gelatin forms thermally reversible gels with water" might allow heating the cartridge to (would it be 40C?) and then flushing. This might mean flushing cartridges with 60C hot tap water for a period of time, might solve the cleaning problem?

It could be tested if someone has some of this gel, by heating in a water bath with a thermometer.

Another cause of this problem is the existence of some cosolvent used in the original CLI-42Y formulation, to keep this particular dye into solution. It could be some phase change technology used by Canon to make the inks more archival: being dye when dissolved, but becomes pigment like or colloidal suspension on paper, greatly enhancing its resistance to fading. Maybe using a 70% alcohol solution with some propylene glycol or glycerol can solve this problem.

Maybe someone can use a pH-meter to determine the intrinsic acidity/akalinity of the OEM yellow ink and adjust accordingly to increase solvability when mixed with 3rd party inks.

Roy said:

If I am reading that correctly, then how will changing the 42 chip to a CLI-8 cart overcome the problem?

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If you purge the CLI-42 cartridge completely clean as in this photo



there still will be enough dried OEM ink left to cause a gelling action to take place inside this cartridge which will then migtate to the print head.

By switching your clI-42 chip over to a CLI-8 cart that will prevent any and all contamination issues between the I.S. ink and the new OEM ink, the problem as @PeterBJ rightly pointed out is the OEM yellow ink itself and not the I.S. ink !

PeterBJ said:

Maybe someone with access to the necessary lab equipment could test this hypothesis?

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Funny you should request that because I reckon I’ve done all the testing that I’m going to do with that crazy CLI-42 OEM yellow ink, my conclusion is yes it does bugger up the print head when diluted with normal 3rd party ink and water !

I think pharmacist's hypothesis may be closer to the truth than mine. I know the use of co-solvents from my work at a paint manufacturing plant, so why didn't I get this idea first?

Co-solvents are used in PVA-emulsion paint and other water-borne emulsion paints, and play a vital role in the drying of the paint. The binder of the paint is an emulsion consisting of small droplets of PVA in water, very similar to white PVA emulsion glue. When the paint is applied it starts to dry by evaporation of water, the main solvent. After the most of the water has evaporated the co-solvent which is less volatile than water makes the PVA droplets form a coherent film. The final drying is caused by evaporation of the co-solvent.

When the PVA is no longer in emulsion but has formed a coherent phase, it is very difficult to re-dissolve, as anybody who has tried to clean a brush or roller with dried PVA emulsion paint will know. If a such emulsion breaks down inside a CLI-42 cartridge, it will certainly be very difficult to remove.

An emulsion might not be present in the CLI-42 Y OEM ink, but a co-solvent could still be used to keep the dye in solution as suggested by pharmacist.

If a co-solvent is used in Canon OEM CLI-42 yellow ink, I think pH testing will reveal nothing.

PVA = Poly Vinyl Alcohol/Acetate, see this: http://en.wikipedia.org/wiki/Polyvinyl_alcohol and this: http://en.wikipedia.org/wiki/Polyvinyl_acetate

Here is more information for the chemists to digest.

The top photo is the drying characteristic of PURE Canon CLI-42 Y ink.
The bottom photo is how normal refill ink dries.

That phase change of the Canon ink does look interesting.

I will upload another photo where indeed, in a dried state, the canon ink appears to be like a gel and gets clumpy. It reminds me of ....swellable paper.

As described, there appears to be two separate issues to this ink...maybe related. One is how it redissolves in the sponge and the dilution factor which occurs at extremely low levels.

mikling said:

I will upload another photo where indeed, in a dried state, the canon ink appears to be like a gel and gets clumpy. It reminds me of ....swellable paper.

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And some swellable papers are/were made with gelatin. Interesting observation of different drying processes

I guess the photos show close ups of ink drops applied on paper by a pipette?