Did you try cleaning it out yourself first? There's a thread in
this forum that describs an excellent method.
This happend to me this evening printing with my Canon s9000 and OD
paper: I was printing 8.5 x 11.00 photos and for some reason they
all had a greenish cast on the prints. I did a nozzle check and
everything appeared ok (all grids printed). I then did a head
allighment check and "column e" (photo cyan) showed no patterns.
This seemed strange to me that the nozzle check appeared that
everything was ok while the printhead allignment check the "column
e" would not show any output. After discovering this I tried the
method mentioned in the following thread:
http://forums.dpreview.com/forums/read.asp?forum=1003&message=5603886
Everything is back to normal now....
As far as a replacement head is concerned, if the print head is
determined to be defective, insist that Canon mail you a print
head. When I reported that my printhead was defective, they
instructed me to bring my printer into a service center. I told
them that it was hour drive from me and I didn't think it
reasonable. They ended up mailing me a replacement head the next
day.
Hope this helps
Bill
PS After receiving the new head, I got the old one to work again!