Canon ip4000 stopped printing

I have a Cannon ip4000, about 3 years old, but have never had a problem. It has just stopped printing. I have run all the clean and alignment tests. I have removed the ink and taken out the print head and put it all back. It goes thru all the motions of printing but the page is blank. Very sudden issue. One minute it was printing and then the next page was, nothing. If I try to run the auto alignment I get the error, orange flashing, reset, and then the same thing. Does this mean the printer head is gone?
 
It might not be the printer. Have you tried the lastest Printer Driver? Is it a networked printer or a USB printer? or on a Print server?
 
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