Are you and have you always used Canon ink.  I have an IP4000 which in computer terms is getting long in the tooth and am not having any problems.

Christopher Jones wrote:

On the nozzle check pattern, the light cyan and light magenta stripes are completely missing. Have tried everything I can think of: nozzle cleaning, nozzle deep cleaning, print head alignment, new ink tanks, new print head, remove and reinstall drivers, but the problem persists. Is there anything else I can try before consigning this printer to oblivion?