Canon i960 print head leak

elsofar

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Here's what happened.
The i960 had been great at not drying out, in spite of very infrequent use. Recently it began to show streaks in the nozzle check and some of the tanks looked empty, so I decided to try a cleaning and refill it with aftermarket ink. This was a 6 color CoYlBod Dye Refill kit, (not specifically for Canon) plus a set of refillable ink cartridges specifically for the i960.
I cleaned the print head using a solution of 10 parts distilled water, 2 parts isopropyl and 1 part ammonia. Filled the new cartridges and reassembled. Got a good nozzle check pattern, everything working!
Back in business, right?
About a week later I went to print something and the colors seemed off. Did a nozzle check and the yellow was showing some grayish tinge. More investigation showed that the black ink was somehow bleeding into the yellow and cyan, which are adjacent tanks. The problem seemed to get worse as I did more testing - green and and bright blue printed almost black. Sure enough, on inspection, the yellow tank was half black and the light cyan looked suspiciously dark. The magentas seemed unaffected.
The print head showed an interesting clue: On the edge of the white ceramic block that holds the nozzles, there were slight streaks of each of the colors, as if the ink was leaking out above the block at the interface with the plastic frame.
So now I have to determine if the problem can be fixed or not. I have several theories:
1. Maybe the ink contained trace amounts of some solvent that softened the glue between the ceramic and the ink galleries (assuming there is any glue) allowing cross-leakage.
2. When I filled the tanks, I didn't notice that they had tape at the top that was supposed to be removed, probably over a vent. Maybe atmospheric pressure cycles forced ink out of and back up into the tanks while the head was parked.
3. The ink accumulated at the parking position during a clean cycle (did not use a deep clean) but the waste pump did not operate to remove it, allowing it to siphon back into the galleries over time.

I'm sure some of these are bogus ideas based on my ignorance. Need some help to tell which which direction to go.
 

The Hat

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I'm sure some of these are bogus ideas based on my ignorance. Need some help to tell which which direction to go.
Ok let’s start afresh, dump that crap ink you bought and buy any 3rd party CANON ink, it doesn’t matter which one just as long as it’s for use in a Canon printer. There is a big difference..

Next also dump the compatible carts and get some OEM carts any of the CLl-8 generation will do and refill them.

Next you need to completely flood your purge pads (Where the Print head sits) and not while you’re using that CoYlBod Dye ink, close the top lid and run a cleaning cycle, then open the top lid and check if the purge pads are clear, if not do the same again and see if the purge unit is clearing the pads..

Summery;- You have a perfectly good printer, so try not to kill it with poor carts and inks..
 

Artur5

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elsofar, the printhead of your Canon I960 ( model QY6-0043 ) is impossible to find new anywhere. Yours must be one of the very few in the world still working OK. As the Hat said, don't kill it with generic ink and avoid aggressive cleaning methods ( i.e. using ammonia ).
 

elsofar

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Yes, the ink will have to go.
After more experimentation and education, the facts begin to resolve:
Theory number 3 looks like the correct one - the parking pad is accumulating waste ink which is seeping back into the ink supply during parking.
After flushing and partially filling the yellow tank, I could get a clean nozzle check, but on the next nozzle check after an hour, the yellow area began to gray. Inspection of the yellow tank showed that nothing had gotten into it so I checked the parking pad - which was saturated! I blotted it dry. Since the nozzle check appears to start with a clean cycle which would load up the pad, I printed a test pattern rather than the nozzle check. The yellow pattern was clean. I ran the same test the next day and the yellow was still clean. And it stayed clean if I avoided doing the nozzle check.
Next step is to disassemble and refurbish the waste pump. I believe The Hat had some postings about pump problems.

The other fact I discovered was that the ink I bought was formulated for Epson printers which use a piezo technology rather than the thermal method used by Canon. I don't know what happens when you run that ink through a thermal print head. Maybe nothing... or it permanently clogs the jets after a while. I see a lot of posts about some aftermarket inks clogging, but they can be cleaned again. Wonder if this is what causes it.
 

Ink stained Fingers

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I don't know what happens when you run that ink through a thermal print head. Maybe nothing.
it just won't print reliably - the thermal properties are different between the inks - the bubble generation iin the Canon nozzles just needs a specific amount of electrical energy which varies with the different composition of the solvents - glycoles + water + colorant + some additives. Running Epson ink in a Canon printer won't damage the printhead in the short term , you just wash it out with a correct Canon ink.
Clogging from aftermarket inks is a difficult subject overall since reliable tests about their differences to genuine inks, their effects onto the printouts and the printhead do not exist but there are plenty of one-off user reports claiming that effect, but without evaluation whether other causes exist like insufficient cartridge ventilation , constructional problems with 3rd party cartridges , incorrect refill practice and more.
 

elsofar

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elsofar, the printhead of your Canon I960 ( model QY6-0043 ) is impossible to find new anywhere. Yours must be one of the very few in the world still working OK. As the Hat said, don't kill it with generic ink and avoid aggressive cleaning methods ( i.e. using ammonia ).
To investigate the waste pump question, I disassembled the i960 so I could clean the pads and watch the operation of the pump. After saturating the parking pad with water at the right instant, I could see it get drained down in less than a second and come out the bottom of the pump. So it was either working all along or started working during my testing process. After reassembling the printer and flushing the yellow tank I did a nozzle check and got a clean test. A week later another test showed the yellow turning gray. At this point I am suspecting an internal leak in the print head, but I don't think it's conclusive yet. I could only see one hose going from the center of the parking pad to the pump, where other posts say there are two hoses. I could not see a second inlet nipple on the pump (but there are two outlets).
Is it possible that the black aftermarket tank could be leaking out through the print head if it was faulty?
Assuming a seal in the print head has failed, has anyone disassembled a print head to tell if it's either possible or impossible to re-seal the ink galleries?
Can't buy more supplies until I prove the print head is OK.
 

PeterBJ

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Canon printheads become fragile when they get old. They can then fail for no apparent reason, either electronically or by an internal leak causing cross contamination. An often seen contamination is black ink entering the yellow cartridge.

The printhead contains a silicone rubber gasket between the upper black part and the white ceramic plate. I once took a printhead apart to see if this gasket was the cause of the contamination. The gasket was OK. There was no signs of leaked ink on the white ceramic plate, so the leakage was inside the ceramic part, under the nozzle foil plate. A leaking gasket might have been cleaned and re-glued, but there is no way you can repair an internal leak in a printhead.

pharmacist has made a popular recipe for a printhead cleaner. A metric drop is 0.05 ml. 20 drops equals 1 ml. This means the amount of ammonia in the cleaner is 1% by volume. Don't exceed this amount of ammonia. In higher concentrations ammonia becomes very aggressive and might damage the printhead. Your formula contains 7.6% ammonia by volume. I think this could very well be the cause of the cross contamination that began after your nozzle cleaning.

I have also made the mistake of using too much ammonia in printhead cleaning. It ruined a printhead. See this.
 
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