Hi Keith.
Happy New Year I’ve solved my Canon printer problem but not as you would have expected.
I removed / re-installed the Linux Mint “Tricia” 19.3 and downloaded the printer and scanner drives from the Canon Pixma TR8550 web site. Then when I restarted the computer the Canon printer was receiving the printer jobs but wasn’t printing them. Also the computer wasn’t seeing the scanner, after various abortive attempts to get the printer and scanner to work I gave up.
My daughter uses Windows and has a HP Envy 5030 printer which we arranged to swap my Canon printer for her HP printer. After connecting the HP printer to my computer upon starting the Mint system it immediately recognised the HP Envy 5050 and I was able to print and scan without any problem.
My daughter says I can keep the HP printer and she will use the Canon printer, so it appears that the Mint 19.3 doesn’t work with the Canon printer as easily as the HP does.
So Keith I thank you once again for your help and patience with me on trying to get the Canon printer to work and I’ll sign this off as “solved” upon receipt of your reply.
Goalie.