You may have ink splattered around the contacts of the printer.
Where the ink cartridge makes electrical contact with the printer can become clogged with ink
When this happens, the ink cartridge wont print or deliver the ink properly.
If you dont have experience with cleaning the area I am talking about, I suggest you take the printer into a shop to have it fully cleaned.
But that is not the ONLY thing that could be wrong.
You could have component failure, and if thats the case, you have to just get a new printer, as it costs more to fix than to buy another.
I know, printers can be a pain in the but.
I have had good luck, and i have had bad luck with canon printers.
I have a conon myself.....and the color cartridge will spew ink all over for some reason.
So open the cover where the ink cartridegs go.....and inspect around and see if you see any ink splattered?
Removed the ink cartridges, and check the electrical contacts on the cartridge and the printer.
If dirty, use alcohol and qtips (lots of them) to clean out the ink.