Our PIXMA G6020 has been very reliable, especially for borderless printing, of which I do a lot.
Last week, it printed 15+ sheets perfectly, then gradually faded from black, to pink, to no detectable output at all (although it's still going through the motions of printing). All standard printing works fine, it is only the borderless setting that results in faded or now blank pages. All ink tanks are at 60% or higher.
To have a better understanding of your issue, please let everyone know the operating system on your computer as well as the program you are printing from. Any other details, such as troubleshooting or maintenance you're attempted, you'd like to give will only help the Community better understand your issue.
If this is a time-sensitive matter, please check out your other support options here: https://canon.us/MyCanonAccount