MG7550 clogged pigment black

[PeterBJ]

This is what I suspect was/is my problem.
After bathing the head the nozzle checks are fine, but as soon as you start to print the ink doesn't come through.
Cleaning cycles do not help.
It is not a cartridge feed problem.

It looks to me like a problem with the purge unit section for pigment black. Have you tested its function? Here is a purge unit test by @turbguy .

 

[mikling]

If the above fails report back.
There is something to consider as well. Inlet filters have a dimensional characteristic attached to them like all filters. Pigment ink also contains solids.

 

[PeterBJ]

I have just finished unclogging an MG5250 bought from a thrift store at DKK 50 or 7 or 8 € or $. The pigment black was totally missing, meaning same error as described by iml and palombian. Click to enlarge:



A stamp test showed the pigment black nozzles were clogged, meaning the print head most likely did not suffer from an electronic damage and could could possibly be saved:

I placed the print head on a paper handkerchief wetted with pharmacists cleaning solution in a tray and pushed down on the print head several times. After some time traces of the pigment black started to show. After more "pumping" much more ink stained the paper handkerchief, and I changed it and repeated the process several times with several new handkerchiefs and pauses between pumping. After several handkerchiefs and a couple of hours I attached a piece of plastic hose to the pigment black ink inlet and filled it with pharmacist's cleaning fluid and just waited for the fluid to disappear from the hose, indicating the nozzles or at least some of them had been unclogged:

Shortly after having finished photographing the setup, the cleaning fluid in the hose had disappeared. I made sure the print head was dry and reinstalled it in the printer. I ran a normal, not deep nozzle cleaning and most of the pigment black nozzles were back. After two more nozzle cleanings I got this nozzle check, click to enlarge:



As can be seen the unclogging was a success, and the dye colours are also good, but sadly the dye black nozzles look to have suffered thermal damage, maybe caused by an unsuitable ink, no cleaning can correct this error:

It is very important the print head is dry before reinstalling, else it can be damaged and it can also damage the logic board, making the printer a total loss. Water or cleaning fluid can be trapped behind the ribbon cable and the circuit board on the back side of the print head. See this. Also see this and this.

 

[martin0reg]

Interesting methods, PeterBJ - I haven't "pumped" on the wet paper towels yet. Could be helpful for dissolving dried pigments, because it's kind of push AND pull. But it won't reach far beyond the nozzle plate, I think.

BTW the easiest and quickest, but not the cheapest, "first aid" would be a canon original pgi cartridge. Assuming that canon knows some ingredients to clean their precious bubble jets, which we and also other ink suppliers don't know... But on the other hand canon can clog and burn out with OEM too...

 

[PeterBJ]

Interesting methods, PeterBJ - I haven't "pumped" on the wet paper towels yet. Could be helpful for dissolving dried pigments, because it's kind of push AND pull. But it won't reach far beyond the nozzle plate, I think.

BTW the easiest and quickest, but not the cheapest, "first aid" would be a canon original pgi cartridge. Assuming that canon knows some ingredients to clean their precious bubble jets, which we and also other ink suppliers don't know... But on the other hand canon can clog and burn out with OEM too...

Maybe the standing on the paper handkerchief wetted with a cleaning fluid is what did the trick and not the pumping? Canon OEM ink might be a good but expensive print head cleaning fluid. In Denmark the normal price of a Canon OEM PGI-525 PGBK cartridge is between 100 and 150 DKK, meaning 2 to 3 times what I paid for the printer. Too much money to gamble on saving what was already a gamble. But sometimes you are lucky and get a good printer almost for free.

BTW the MG5250 had OEM Canon CLI-526 C-M-K and aftermarket PGI-525 PGBK and CLI-526 Y cartridges. Probably the aftermarket pigment black cartridge clogged the print head? I don't know what damaged the dye BK nozzles, the EEPROM info doesn't tell the brand of the previously installed cartridges, so maybe some bad dye black cartridge had been installed earlier?

 

[mikling]

I have just finished unclogging an MG5250 bought from a thrift store at DKK 50 or 7 or 8 € or $. The pigment black was totally missing, meaning same error as described by iml and palombian. Click to enlarge:

View attachment 5680

A stamp test showed the pigment black nozzles were clogged, meaning the print head most likely did not suffer from an electronic damage and could could possibly be saved:

View attachment 5681

I placed the print head on a paper handkerchief wetted with pharmacists cleaning solution in a tray and pushed down on the print head several times. After some time traces of the pigment black started to show. After more "pumping" much more ink stained the paper handkerchief, and I changed it and repeated the process several times with several new handkerchiefs and pauses between pumping. After several handkerchiefs and a couple of hours I attached a piece of plastic hose to the pigment black ink inlet and filled it with pharmacist's cleaning fluid and just waited for the fluid to disappear from the hose, indicating the nozzles or at least some of them had been unclogged:

View attachment 5682

Shortly after having finished photographing the setup, the cleaning fluid in the hose had disappeared. I made sure the print head was dry and reinstalled it in the printer. I ran a normal, not deep nozzle cleaning and most of the pigment black nozzles were back. After two more nozzle cleanings I got this nozzle check, click to enlarge:

View attachment 5683

As can be seen the unclogging was a success, and the dye colours are also good, but sadly the dye black nozzles look to have suffered thermal damage, maybe caused by an unsuitable ink, no cleaning can correct this error:

View attachment 5684

It is very important the print head is dry before reinstalling, else it can be damaged and it can also damage the logic board, making the printer a total loss. Water or cleaning fluid can be trapped behind the ribbon cable and the circuit board on the back side of the print head. See this. Also see this and this.

When you have the hose on the large inlet and filled with a column of liquid. Invert the setup to allow a vacuum effect. With the PGBK, it is a good idea to backflush. This is important when the nozzle checks show little flow after a soak. Some pigment inks suffer from non uniform grinds and may have larger particles that get trapped in the inlet filter. I have seen this a few times.

As for the nozzle checks after a soak....do not let that slightly imperfect check bother you at this point. When picking up used printers where the printhead may have been dried out and used unknown or even known ink that had dried out, the imperfect pattern does not necessarily mean that the nozzle is a goner. It might not be. Just keep printing lightly with it a page a day or so over a long period and might come back. Only time will tell.

As for the BK patter displayed. This could be a sign of delayed firing. The nozzles are possibly insulated with dried ink preventing heat from quickly heating the ink. I would install a cleaning cartridge with some windex in it and over a period of days see what comes of it.

I have some printable liquid that can be used instead of windex that will not leave deposits and it is safe in the print mode just like ink.

 

[iml]

If the above fails to resolve then post back. I think I know the solution but do as stratman has outlined first. BTW, how much pigment black has been put through the printhead so far?

Just 5 fills. You will see the poor condition the head is in and you will freak out (as I did)

I probably have to test the purge system next. There is not much clearance with the newer canons to safely spill some water there with the syringe. For now I will be soaking the printhead following @stratman's extra encouraging instructions. Fairy it is for me.

Question: Wouldn't water stay in the waste pads filling them prematurely with this purge test? I suppose that the "upper tank" (where the printhead rests) doesn't take much to fill but I have some second thoughts.

From the photos you can see that even with a... chisel I could probably partially unclog the printhead. No amount of normal cleaning cycle could unclog this. How did it get so messy?
I'm also curious about the -I guess- pigment concentration especially around the dye color nozzles. What is it doing there?

 

[mikling]

Just 5 fills. You will see the poor condition the head is in and you will freak out (as I did)

I probably have to test the purge system next. There is not much clearance with the newer canons to safely spill some water there with the syringe. For now I will be soaking the printhead following @stratman's extra encouraging instructions. Fairy it is for me.

Question: Wouldn't water stay in the waste pads filling them prematurely with this purge test? I suppose that the "upper tank" (where the printhead rests) doesn't take much to fill but I have some second thoughts.

From the photos you can see that even with a... chisel I could probably partially unclog the printhead. No amount of normal cleaning cycle could unclog this. How did it get so messy?
I'm also curious about the -I guess- pigment concentration especially around the dye color nozzles. What is it doing there?

View attachment 5688 View attachment 5689 View attachment 5690

Looks like you have a purge unit (PGBK) on the printer that has likely become disconnected. The only way to remedy this is to take the printer apart.
I had an MP500 that looked so similar in its characrteristics. You are likely to see the wipers also encrusted with pigment goo. Time for surgery or start looking for an alternative.

 

[iml]

After soaking the PH for 48 hours in distilled water with fairy and pushing the PH to a paper handkerchief from time to time, then replacing the solution used, I left the PH for almost 3 days to dry. Would have been more (I think I totaled my last PH due to not being patient enough) but I needed to use the printer. The colors took some time to appear (had to wait several hours and extra 3 normal cleaning circles between nozzle checks) but now I have a perfect nozzle check once again.

PGI-Black and CLI-Yellow are canon OEM cartridges now and I will be replacing the other ARC cartridges as soon as they are declared empty.
Oh the joy...!
A big "THANK YOU" for all the help you gave me

Meanwhile, I cleaned (the best I could) wipers and whatever I could reach from what I reckon "too much pigment black".

The purge test is yet inconclusive. I could see the squared purge pad emptying after a cleaning circle, however the long-narrow one (for bk-pigment) is to far from reach, narrow and shiny from all the excess bk color to be sure at this stage. I will have to come back on that.
Are there any instructions -anyone came by- for diassembling the MG7550 or some similar model?

 

[PeterBJ]

Congratulations with unclogging the print head. Well done

Service manuals for printers newer than the PGI-x25/CLI-x26 cartridge generation seems nowhere to be found, and other instructions seem to be equally scarce. If you find any disassembly instructions please post a link.