Canon i9100: colors printing incorrectly

I've had the Canon i9100 since 2003 and have excellent photo printing results. In 2009 it started playing up and I'd gt some banding. More recently, black didn't want to print. It was as though the black ink in the print head got dry some days.

April 2010 - The colours started printing strange and I bought a brand new print head and installed it. Only takes a minute. Still had an issue with photo printing. Black and white was excellent but colours weren't true.

Found advice online to try cleaning the print head to print head carrier electrical contacts by rubbing them with a rubber eraser.

I did that and now I'm getting perfect colour photo prints again.

I had been thinking about buying a new A3+ printer but this is old printer is now working as good as new.

Simples.
Uninstall/Restart/Install setup disc's/ run to sequence. Test page.

If still not working right , run printhead facilities two or three times.

Otherwise suspect cartridges.