It's a pretty old printer, read this, fix the printhead or replace the printer, whichever you prefer.
"What an amazing printer. The print head died after 5 years of incredible print quality, and service. I tried to upgrade to the PIXMA ip4600 but soon realized that was a mistake - the standard print quality, noise, and klunkiness of this supposed successor was a joke and pailed in comparison to my beloved i960! After much headache to return the ip4600, and spending nearly the same price of what the printer did 5 years ago on the cost of repair, my i960 are now happily reunited. Canon, why did you discontinue this amazing product?"