[Solved] Fuzzy black text from Canon TR8520 printer

My Canon printer recently started to print some fuzzy text on some of the lines on a page. I ran a nozzle print check and saw some blurred lines on the lower part of PBGK pattern; the color patterns looked fine. I assumed I had some debris in the PBGK portion of the print head and ran a cleaning cycle, which had no effect. I then did some manual cleaning of the print head, soaking it in a solution of 10 parts water, 2 parts isopropanol and 1 part ammonia. This had no effect on the nozzle print pattern or printed text. I did an overnight soaking of the print head in the same solution and wiped the pins contacting the print head on the printer, but the results were unchanged. I also replaced the black PBGK cartridge with a new one, with no effect. What's interesting is that when I compare the same page of text, the same lines that were blurry before cleaning are blurry after cleaning, and the same for the clearly printed text. See attached nozzle check results and sample text. Thank you, in advance, for any suggestions on what the issue might be. (The scanned nozzle pattern looks worse than the actual printed pattern, and the scanned text looks better than the actual printed text; red arrows indicate blurry lines).

 

Actually, the light colors are on the printed page, but didn't scan well. But I'll try the deep cleaning. I hesitated to do that since I know it uses a fair amount of ink and didn't think it would be as effective as the manual cleaning. Thanks for the suggestions.

 

The deep cleaning did not change the nozzle print pattern. I’m going to clean the pins contacting the back of the print head and the pins contacting the ink cartridges to see if that might help. Also, I can try cleaning the timing strip on the printer, if I can figure out how to access it. Any other suggestions would be welcome.

 

I cleaned the pins to no effect. I did a more extensive cleaning of the printhead, adding a little laundry detergent to the cleaning solution above and soaked overnight. After rinsing and drying the printhead, there was no change in the nozzle check. Canon requires a service contract after the warranty period has ended and the Canon community has not been very responsive to my post about this issue. The printer is 6 years old but relatively lightly used (which may be part of the printing issue) and had been working well until recently. I am ecologically minded and would rather try and fix the problem rather than buying a new printer, which, of course, I would do if necessary. I'm now looking into replacement printheads. The issue with the replacement is that there are only a few reviews for the few replacements I see online, and the reviews are not spectacular in general. I'm wondering whether to purchase one and take my chances. Any suggestions would be welcome. Thanks.

 

To follow up, I ordered and installed a new printhead. The printed text is now sharp and clear! I try to fix things whenever I can, but sometimes you can't (sigh), and they need to be replaced.