Canon Mp500 - What Are These Tubes? - Cleaning Problem Printing Black Pigment

[stratman]

Unfortunately, prior to my complete understanding of how this works, I gave out a lot of incorrect advice for the MP780 and iP4000 printers, that you could easily tell if your purge unit was clogged by putting Windex or water on the purge pads, closing the lid and re-opening it to see if the liquid had been sucked away. That's how it worked on most of my printers, which, in fact, had that second tubes clogged and not the tubes going to the purge unit. If you do that little exercise, it should not clear the pads. If it does, it means those extra tubes are clogged. So if the pads are not cleared, it could be because your printer is working correctly or the purge unit is clogged. The correct test is to do a cleaning.

It turns out that if those extra tubes are clogged, your printer can still purge the print head and it can work properly but it will dump a lot more ink into the waste tank and not keep track of it so you can have an overflow of your waste tank before the printer warns you of the possibility, especially if you are putting a lot of Windex or water on your pads regularly just for preventative maintenance. That happened to me on one of my printers. When I lifted it up for an unrelated reason, I discovered that it was hiding a pool of black ink under it.

The OP's purge test with flooding the purge pads and then doing a cleaning cycle is indicative of what then? Working or not working purge system? Is the purge system ruled out as malfunctioning or not?

Is this like the Karate Kid movie where Mr. Miyagi instructs Daniel to "wax on, wax off" but without the reason why?

 

[ghwellsjr]

After you put Windex or water on the purge pads, then do a cleaning cycle, if it's gone, the purge pump is working.

Then, if you want to test the additional tubes and you have a printer like mine, then you can put liquid on the purge pads, close and re-open the cover, if it's gone, the additional tubes are clogged and you should be wary of the waste ink tank filling before the printer warns you. I have no idea if this process works the same on other printers.

 

[stratman]

After you put Windex or water on the purge pads, then do a cleaning cycle, if it's gone, the purge pump is working.

Then, if you want to test the additional tubes and you have a printer like mine, then you can put liquid on the purge pads, close and re-open the cover, if it's gone, the additional tubes are clogged and you should be wary of the waste ink tank filling before the printer warns you. I have no idea if this process works the same on other printers.

The forum has discussed and recommended this purge system check maneuver for years but I do not recall your observations previously. Yours is a significant and potential paradigm altering comment.

 

[Robert the Bruce]

Update: I think it's working!
I decided to take out the print head and have another go at cleaning out the pigment black. I carefully flushed some cleaning fluid through the nozzles using a syringe and tube sealed around the PGBK ink port. After reinstalling everything and printing an initial nozzle check I got this:

You can see it's slightly washed out, as one would expect after using cleaning solution.
I then did a few more nozzle checks, and finally got this:

Afterwards I printed a page of sheet music (i.e. black and white, which is what I mostly use this printer for these days) and it looks almost perfect - just a slight hint of grey at the bottom of a few pieces of text where it should be solid black.
Fingers crossed it will continue working!
I did wonder whether there was some problem in creating the vacuum necessary to keep the ink flowing, but perhaps it was just dirt in the channels or nozzles after all.
Even if it does fade again, at least I know that the print head nozzles are all OK

 

[stratman]

Great job, Robert! Perseverance pays off. Why a "new" print head would do this is a mystery. Maybe there was ink starvation from the cartridge. To maintain proper function I would suggest flushing the old cartridge and then refill or switch to a new OEM pigment black. Why risk further trouble.

Let the print head rest over night and then try printing your sheet music again to see if all is well. The nozzle check looks super over all with one bottom most horizontal bar in the tenth column from the left.

To decrease your risk of a clogged print head in the future, print a nozzle check, or something that uses ALL cartridges, once a week.

Again, well done.

 

[Robert the Bruce]

Thanks to everyone for their help and advice - I couldn't have done it without you!
@stratman is there any way of keeping a cleaned print head working without leaving it in the printer and doing a weekly print? I've been soaking the old one in cleaning solution for about 24 hours now.
I suspect the old head had fused colour nozzles, and the black is the only one I'd be confident of with that one. I would rather not change print heads at the moment, but keep the old one as a spare for B&W printing. Is it possible to put it in a sealed bag or something so it doesn't dry out completely?

 

[PeterBJ]

Thanks to everyone for their help and advice - I couldn't have done it without you!
@stratman is there any way of keeping a cleaned print head working without leaving it in the printer and doing a weekly print? I've been soaking the old one in cleaning solution for about 24 hours now.
I suspect the old head had fused colour nozzles, and the black is the only one I'd be confident of with that one. I would rather not change print heads at the moment, but keep the old one as a spare for B&W printing. Is it possible to put it in a sealed bag or something so it doesn't dry out completely?

Do not put the old and defective print head back in the printer, for doing maintenance printing or for other purposes. A defective print head can damage the logic board, and the now damaged logic board can damage a new print head. Swapping print heads between printers for instance for troubleshooting is a bad idea.

Maybe the best way to preserve the old print head, to use in an emergency for B/W only printing, is to flush it with de-mineralized or distilled water and allowing it to dry. If you decide not to keep the old print head, then keep the rubber gaskets as spares. Else you will have a problem if you loose a gasket from the new print head.

BTW congratulations with bringing the printer back to life, well done!

And thanks to turbguy and ghwellsjr for the explanations about the functions of the purge unit. I have a much better understanding of the purge unit now.

 

[stratman]

Instruction on how to store a used print head at http://www.printerknowledge.com/threads/how-to-store-a-print-head.6343/#post-47497.

PeterBJ makes a valid point about the risk to your new print head from the old print head. I'd rather have a spare new print head than rely on an old known damaged one.

 

[PeterBJ]

Instruction on how to store a used print head at http://www.printerknowledge.com/threads/how-to-store-a-print-head.6343/#post-47497.

Thanks for the link. I knew pharmacist's cleaning and conditioning solutions, but not the preservation solution. I have bookmarked the link.

 

[stratman]

Thanks for the link. I knew pharmacist's cleaning and conditioning solutions, but not the preservation solution. I have bookmarked the link.

It is how I stay so youthful looking at my age.

You are most welcome.