I have vertical banding with my MX922 looking like:
https://community.usa.canon.com/t5/Desktop-Inkjet-Printers/Pixma-mx922-shadow-printing-even-after-auto--manual-align/m-p/336095#M12613
Canon tells me to clean the transparent band to correct both this problem, - as well as the BK lowest bar on the test page printing blue instead of black.
I opened up the printer as they show users to do and the transparent band was completely filthy! If the band is so sensitive and the effects so far-reaching, I am surprised it has been working fine for so long! anyway, I cleaned the dirt off with a tissue and rubbing alcohol and firstly, there is no difference to the banding at all, if anything it is worse? But secondly, the BK band is no longer blue, - it is now completely gone??
I'll bet I got 95% of the dirt off the front of that band. Is completely cleaning that band for a few hours the solution here or is it a wild goose chase? I do see on that Canon community support page Canon likes to tell people to clean the band prior to telling them to buy a new printer. to solve this problem.
I have already been told to buy a new printer with this MX922, prior to discovering that the whole problem causing the YOUR PRINTER HAS DIED error message lay with a small piece of paper lodged in the paper path somewhere. So I cant help but think that possibly Canon might conceivably have some ulterior motive for telling me to buy a new printer?