There are several reasons behind the Canon printer not printing Black issues problem.
It can be due to the clogged cartridges and print head nozzles.
Besides this, your black ink might be running short, making your Canon printer not release it.
Every time your Canon printer’s nozzles are blocked with dust; it prevents ink from coming onto the paper.
For fixing it, you should ensure to clean the nozzles and ink cartridges of your Canon printer.