IP3000 cross contamination - cause?

[The Hat]

@kanonvater, It’s more than likely that the seal in the bottom of the print head have given up for what ever reason, resulting in the colour mixture your getting on paper and in your purge unit.

When you get your new print head that should solve all your problems hopefully, but before you install the new head you should give the purge unit a very good clean, I mean a GOOD clean, give it the gold standard treatment...

 

[kanonvater]

"you should give the purge unit a very good clean ..."

Thanks again! I hope you'll pardon my ignorance -- how would I do that? Dump a bunch of Windex into it? I wouldn't think that a head cleaning after Windex irrigation would be the way to go, since that would just put more ink into the pads.

I have a couple of dental irrigation syringes with curved tips around here somewhere. They might reach into the purging unit. Maybe use one to squirt Windex in, and one to suck it out?

I guess I'd do this with the head in ink-change position and the power cable pulled, yes? That way the old head wouldn't wander back over to the cleaned purging unit and ink it up again.

I'm a little uneasy about putting too much extra liquid into the purging system, with the printer's drain sheet sliding toward 75% full.

 

[kanonvater]

BTW, after I changed the yellow cart, the nozzle check changed too. Check this out.



Could it be that the yellow cart had a bad vent or seal and was leaking enough to overwhelm the cyan? And now it isn't?

There's still definitely a cyan problem, which continued after a cart change. (However, I'm now wondering if maybe I should try yet another cyan cart.)

Here's the nc after one head cleaning. There's still some cyan in the magenta, but it's better, and the yellow looks clean.

 

[kanonvater]

A new (I hope) printhead and we're back in business:



I couldn't find much on cleaning the purging pads, so I winged it: dripped Windex on them with a syringe, and sopped it up with cotton swabs.

Even the pgb is looking good now. Previously I thought the few missing segments might be ink starvation, since they moved around with different nozzle checks. Now I wonder just what it really was.

Regardless, all seems well now.

Thanks for your help with this!

 

[Tom Hock]

I have had cross contamination from time to time also, but it doesn't seem to be consistent. I rotate ink tanks rather than filling the same one when it runs low. This made me think the problem may with the ink tanks themselves. This is a long shot, but if the venting of an ink tank is not perfect, a very slight vacuum could be created in the tank, especially during a purge cycle, and this could cause ink to be drawn in at the nozzle plate when sitting on the rest pad. I know this sounds far fetched, but easy to test just by changing to a different ink tank.

 

[kanonvater]

That's an interesting idea, but wouldn't you think that if the vent weren't admitting enough air, you'd get ink starvation while printing?

On the other hand, if the vent is allowing TOO MUCH air into a cart, I can see how that cart's ink might flood the purging pad while the head is parked (with no purging vacuum). The excess ink might then be able to wick back up into the head by capillary action. But that's just a guess.

 

[The Hat]

@kanonvater, The only way the Canon cartridge can leak is by an unsuccessful refill, i.e. not sealing the refill hole properly, the top air vent can never cause a leak to occur, and as you rightly pointed out, if the air vent is blocked it will cause ink starvation...

 

[Tom Hock]

I agree a blocked vent would cause ink starvation when printing, but what if the top sponge was so plugged up, or restrictive, it could not breath well enough to handle the larger venting volume of air
required during the purge cycle, but still open enough to handle the very small amount of venting required while printing. This might, for a short period, create a very slight vacuum in the ink tank and print head at the time of purge pump operation. Like I said in my earlier posting, I know this is a long shot, but easy to test.

 

[Ink stained Fingers]

There are at least two different types of causes for cross contamination - there are thin elastomer/rubber seals between ink channels in the printhead just before the nozzle plate, and these seals get weak over the years since they are constantly exposed to the ink solvent, and this allows ink to pass from one color channel to the next one. And there is a completely different effect by the sponge in the cartridge , the sponge when not completely saturated holds back the ink and creates a small level of negative pressure on the ink channel, and this can cause ink being sucked back from the purge unit in the idle position , this becomes most clearly visible when the yellow cartridge is pulling such black ink back and the bottom of the cartridge turns black. It is advised that the sponge gets partially saturated with ink aside from the chamber being filled up again during a refill action, and there is another reason to partially saturate the sponge , only that ink can pull ink from the chamber, as soon as you get an air bubble in front of the little openings at the bottom of the chamber the ink won't flow anymore and will cause ink flow problems which appear to be nozzle problems but they aren't. It's a delicate situation with very small pressure differences within the cartridge.

 

[kanonvater]

"the sponge when not completely saturated holds back the ink and creates a small level of negative pressure on the ink channel, and this can cause ink being sucked back from the purge unit in the idle position..."

This sounds like an argument for refilling all your carts as soon as the printer sounds the "ink is getting low" alarm on any one of them. Or, better yet, when you get to 1/4 or so remaining.

If you did let some of the sponge side ink get used before refilling, could you drip a little ink into the outlet port to refill the sponge at the same time you refill the other side? Or would that tend to just drip out?