Printhead dying or just old inks?

[Gabriel_21]

Hey, hope some people with experience could point me in the right direction with my little problem.

My Canon Pro 4100 suddenly started printing Nozzle Checks where the darker columns for CO are pretty much black or at least very dark grey, which from what I understand would mean major clogging since CO is supposed to be put on top of black color in Nozzle Check patterns forming the grey/light grey columns. I don't really get lines in the columns, just dark columns or a gradient effect in them with top of the column being grey while the bottom being dark.

After Cleaning, the Nozzle Check pattern turns to perfect but there are two problems, the clogging appears soon after, once it even appeared minutes after because I turned off and on the printer to go from Service Mode to normal user mode. And the other problem is a change in color tint in the prints, towards magenta, even after Cleaning with perfect Nozzle Checks. The magenta tint is stronger when the CO columns on the nozzle check pattern are fully dark and of course is barely visible after Cleaning when the Nozzle check pattern is perfect but it still doesn't match the tint that the prints had before this problem started occurring, not even after a Color Calibration. The old prints still look slightly warmer, more greenish tint and they also have slightly more contrast while the new ones seem a little more dull.

Now some clarification, the Printhead was installed in the printer on 2021/07/25 but I did not print heavily with it, mostly test prints in preparation for a printing activity and Nozzle Checks to keep the ink flowing and avoid Self-Cleaning. Total Dot Count is 107604 and surface printed is 31.1 m2 ( 335.6 sq.f ). I'm still not experienced with the printer but seeing some other people's numbers online I would say that the printhead wasn't heavily used. The Diagnosis/Nozzle Check option in the Service Mode shows me OK for all colors and the printer Info tells me I have 2 Non-Ejection Nozzles, 1 for PM (A-a) and 1 for PGY (A-d).

Printer Info shows that the 160 ml CO cartridge was installed in the printer 541 days ago. Is that too long of a time for the ink? Could the degrading quality of the ink inside the cartridge be the problem for this constant clogging and not the Printhead?

[Tuco]

Entirely different printer (Epson p900) - but I had thought I may be terminally clogged, often losing a whole color channel.  Many nozzle flushes later I finally replaced the carts on the colors having problems, which were kinda low anyway, and my problems seem to have gone away.  Printer doesn't get used much, so those carts were probably nearing a couple years old.  Seems worth a shot.

[Lessbones]

there shouldn't be any color at all in the CO, it should be barely visible...  It sounds like it may be picking up ink from your capping station-- try using some cleaning solution to clean off the place where the heads park, it might be that the sponges the head sits against are hardened and not draining properly--

[Panagiotis]

I print with the PRO-4000 since Feb 2019. The printer is it's third printhead. The first time the printer asked for a new printhead at May 2021 (27 months, 600 square meters) and the second at June 2023 (25 months, 1650 square meters). The second at the end it started to print the skies magenta on mat papers and very dark (like dirty) the CO at the beginning of PBK paper prints. Both problems disappeared with the new printhead. 
Yours is also two years+ old so I believe is the printhead.

[Gabriel_21]

I print with the PRO-4000 since Feb 2019. The printer is it's third printhead. The first time the printer asked for a new printhead at May 2021 (27 months, 600 square meters) and the second at June 2023 (25 months, 1650 square meters). The second at the end it started to print the skies magenta on mat papers and very dark (like dirty) the CO at the beginning of PBK paper prints. Both problems disappeared with the new printhead. 
Yours is also two years+ old so I believe is the printhead.

Interesting, so you think even with this low printing volume my printhead is still going? Btw you know of some surefire troubleshooting that could point more surely to the printhead being the problem? Would any of the Diagnosis tools from the service mode help? And when you changed your Printheads did you lose any ink? The manual says the ink is brought into the system for printhead replacement, so its not purged/lost?
Thanks for your answer btw

[Gabriel_21]

there shouldn't be any color at all in the CO, it should be barely visible...  It sounds like it may be picking up ink from your capping station-- try using some cleaning solution to clean off the place where the heads park, it might be that the sponges the head sits against are hardened and not draining properly--

I saw this solution for another type of printer that had same reoccurring clogging problem, but Canon manual didn't show anything for how to get to the Printhead area. Will try to see if there's anything in the Service Manual regarding this or maybe something on the net. Thanks

[Gabriel_21]

Entirely different printer (Epson p900) - but I had thought I may be terminally clogged, often losing a whole color channel.  Many nozzle flushes later I finally replaced the carts on the colors having problems, which were kinda low anyway, and my problems seem to have gone away.  Printer doesn't get used much, so those carts were probably nearing a couple years old.  Seems worth a shot.

Yeah I think I should do that too before considering the more expensive option of changing the Printhead. I was just wondering if I lose any ink when I change the printhead, the manual isn't very clear on this, cause if so I'd prefer losing the actual older ink and then get new cartridges.
Thanks for your answer

[Panagiotis]

Interesting, so you think even with this low printing volume my printhead is still going? Btw you know of some surefire troubleshooting that could point more surely to the printhead being the problem? Would any of the Diagnosis tools from the service mode help? And when you changed your Printheads did you lose any ink? The manual says the ink is brought into the system for printhead replacement, so its not purged/lost?
Thanks for your answer btw

During the replacement procedure ink is lost (goes to the maintenance tank). I cannot calculate how much but keep a replacement MC-30 nearby.

[Lessbones]

Yeah I think I should do that too before considering the more expensive option of changing the Printhead. I was just wondering if I lose any ink when I change the printhead, the manual isn't very clear on this, cause if so I'd prefer losing the actual older ink and then get new cartridges.
Thanks for your answer

There are posts on here about how to get into the service menu-- it's a little annoying because of the touch screen (i'm pretty sure i've posted the procedure myself if you check my posts) but once you get into it, you'll want to go to CR_UNLOCK which i believe is in the FUNCTION section-- you wait a few seconds until it stops making noises and then you should be able to manually pull the head over to the left to expose the capping station.

[Gabriel_21]

There are posts on here about how to get into the service menu-- it's a little annoying because of the touch screen (i'm pretty sure i've posted the procedure myself if you check my posts) but once you get into it, you'll want to go to CR_UNLOCK which i believe is in the FUNCTION section-- you wait a few seconds until it stops making noises and then you should be able to manually pull the head over to the left to expose the capping station.

Already did that, tried to clean the purge pads thinking maybe they were affecting the printhead but they were normal and didn't solve my problem. I saw there's the Function Head Replacement in Service Mode and its manual function description says " Removing or installing a print head again without withdrawing  ink inside the print head" . Did you ever use that function? Does it mean I can get the print head out without losing any ink? And could this Function work for a new printhead installation or this is only for the same printhead , just to be able to get it out and put back without ink loss?

[Lessbones]

I've never used that setting, but by the description it does sound like it would work to get it out if you're just trying to manually clean the head.  I've done this before by just yanking the power cord and removing the head so it doesn't know it's being taken out, but just be careful flipping the head over or it might spill a bunch of ink everywhere.