Re-glue ceramic part to print head

[turbguy]

Interesting...there is no type of sealant between the nozzle plate and ceramic? Since the cooeficient of expansion between the materials can vary, (and the nozzle plate definitely gets hot), I would expect SOMETHING is used to prevent inter-channel leakage.

 

[Emulator]

The seals between the ceramic plate and the grey plastic gasket use semi 'O' ring technique, (see image and enlargement below). 'O' ring seals can withstand thousands of PSI pressures on things like SCUBA equipment, so even these molded half ring seals should be good, without any additional sealant unless, they are poor quality.



You can see that the only additional sealant/adhesive on the 9000 II head is the ?"silicone"? band around the ceramic plate, making contact with the aluminium heat sink plate. This failed in use on my 9000 and the plate rattled when the head was shaken. Presumably this might have led to the ceramic plate over heating in use.

I think the intermixing of ink must occur in the joint between the ceramic plate and the actual printhead plate.

Or could it even occur by excess ink accumulating below the printhead jets and merging while the printer is not in use?

 

[martin0reg]

Emulator, like you I think that there is probably no additional adhesive to seal the contact between gasket and ceramic, the pressure seals the gasket rings over the ink holes.

Which is the second of three steps: first the "tubing" in the black plastic body, second the gasket between body and ceramic, third the actual nozzle plate on the other side of the ceramic. Softest target is the silicone gasket, isn't it..?
I suspect that the sealling contact could "wear out" or break. Perhaps even more when the printer stands idle for YEARS, loaded with ink, like the second of my ip3000...

...
Or could it even occur by excess ink accumulating below the printhead jets and merging while the printer is not in use?

This would mean, that the purging pad is full of ink...which I did not noticed on this ip3000.
But all three color cartridges were totally contaminated, all dark grey ink, when I received the printer (untouched since 4 years when my husband died, said the woman who gave it to me)

 

[Emulator]

Have you inspected your gasket? It depends on the material used, but from the look of mine it is still in good condition. The ink pressure on the seal must be very small, unless someone uses a syringe to unblock the head, but even that is unlikely to disrupt that sort of "O" ring seal.

The all grey ink on the head jets sounds a bit suspicious, I think it is true to say that this is not normally the case.

When you separated the ceramic plate from the electrical printing head, (something I have not done) what type of seal was there between each colour section?

 

[martin0reg]

...The all grey ink on the head jets sounds a bit suspicious, I think it is true to say that this is not normally the case...

Note that it took 4 years to mix the ink in all three color carts!
When I received the printer first of all I took the carts out, then flushed the head on paper towels. Put the clean head and new refilled carts back in, first prints were fine... until the yellow becomes red. After only one day contamination was not only in printing but also visible at the cart outlet / bottom of the sponge.

...When you separated the ceramic plate from the electrical printing head, (something I have not done) what type of seal was there between each colour section?

Look at the last two photos: the actual nozzle plate (for the photo ink channel: the tiny square, golden on the printing side) sits directely on the "back" (or front, as you like) of the ceramic.
There are five "slots" or "grooves" in the ceramic, as counterpart of the five holes on the gasket side. The grid of the nozzle plate (back side) fits exactly on the grooves of the ceramic.

There might be some gluing or sealing used when it's originally mounted, anyway I had to destroy this bonding..

 

[The Hat]

I still reckon the contamination was probably cause from the cartridges themselves sitting in the print head untouched for four years and the rubber seals were depressed for so long that they have not been given enough time to recover, or use a rubber rejuvenator on them if it not to late..

 

[martin0reg]

This photo shows the head without the rubber seals around the inlets. I took them out for flushing the head on paper towels with tubes on the inlets, filled with cleaning solution. Meanwhile I use to clean these rubber parts in warm water. So everything was fine at this state... until ..

Besides I think these rubber seals can cause problems with ink flow, but probably not cross cantamination, because at this step the inks are still seperated. In other words: how could M flow in Y before entering the inlets?

My speculation that the years of idle time may be the reason not only for the contaminated carts, but also for the main problem: contamination in actual printing - has one big counter argument: the other printer was used ... not often but often enough that the carts were not contaminated. And this one showed almost the same strong contamination of Y and M !

On the other hand, this one possibly had also long idle times ... which is not good in general, regarding cloggs and perhaps intermixing ink channels too

After installing a brand new qy6-0064 in the printer (the one which is not damaged by installing a bad head) the printing is flawless, like new. No more contamination / ink mixing. So I can confirm that it had to be due to the head, not the purging unit. But the question remains, which part of the printhead fails and for what reason?

 

[The Hat]

@martin0reg, what ever the reason was for the cross contamination is of little importance now, (Maybe the previous owner had the same problem for ages) because you got her back up and running like new, that’s the best news of all, congratulations..

 

[turbguy]

After installing a brand new qy6-0064 in the printer (the one which is not damaged by installing a bad head) the printing is flawless, like new. No more contamination / ink mixing. So I can confirm that it had to be due to the head, not the purging unit. But the question remains, which part of the printhead fails and for what reason?

Great question.

IMO, there MUST be some type of sealing used between the nozzle plate and ceramic, otherwise leakage between channels would be inevitable. When this proposed sealing fails, cross-contamination is the result.

 

[Emulator]

If leakage leading to mixing is to occur between openings on the rubber gasket and the ceramic plate, the ink has to pass two half "O" ring seals, an unlikely series of events, when it is free to escape out the sides.

Leakage between openings on the ceramic plate and the nozzle plate is not unlikely if the adhesive holding the latter breaks down. There must be an adhesive as there is nothing else holding the nozzle plate in place. There appears to be a pink coating in your image.