Had a similar problem with my canon , after several cleans and several original and compatable cartridges it still remained the same
as said above the print head was seperate and can be removed , again cleaned and looked fine , I was about to give up until my friend was upgrading his printer as print feed mechanism broke , so I decided to play frankenstein with the two printers
First thing I tried was swapping the pint head , and what do you know this fixed it lol
After speaking to my mate at the local computer shop I was told there is a chip on the print head and in his experience these can become faulty
so I suggest trying to pick up a replacement print head fixed my situation