Canon MP780 printing stripes?

[John Leary]

My MP780 is exhibiting banding in both blue and magenta. (Yellow and both blacks seem okay.) Repeated cleaning cycles, both CLEANING and HEAD REFRESHING, seem to make no difference.

I've uploaded a scan of the latest nozzle check:
http://georgestreetcoop.com/images/MP780NozzleCheck.png

Any clues what I should do next?

 

[stratman]

Usually people ask whether you've tried new Cyan and Magenta cartridges to see if that would fix the problem, or, be asked to check the purge system. Probably not needed in your case because of the shape and extent of the printing defect.

The issue is a malfunctioning print head or logic assay board, most likely the print head since you did not report any error message and the defect is "perfect" in shape - straight-edged blocks of missing (less) ink. There is no guarantee, but experience leans in favor of the print head.

I did see some for sale on Google Shopping and eBay. Maybe Canon Sales or one of their authorized repair shops in your area have them.