How to uninstall a printer driver?

In the office where I work with my Mac there's a Canon copier/scanner model iR2318. Months ago I downloaded and installed the Lion compatible drivers required that worked fine.

• Yesterday (with no reason, no changes, nothing at all: just working) the printer started to refuse to print as it asked for a different paper format: A4 or Letter. Despite many attempts to specifically send print jobs in A4, which is the paper format loaded in the tray, the printer continued to refuse all prints.
• Today I ended up removing the printer from the list, as it became unnecessary, and I also liked to uninstall the printer driver as well, since Canon released a newer version.
• Currently, when trying to reinstall the printer, 2 drivers are displayed: UK and US. This lets me assume that those 2 drivers are still installed in my system: I wanted to remove both of them and start from scratch by reinstall the driver and he printer as the system was new.

How can I remove the driver, so that Lion won't recognize it and that I could make a clean install of the previous working printer?

Please…as a former Windows user, the most unwanted answer is "try to recover your system"!