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This looks to be toner starvation on cyan and magenta, or a misaligned transfer belt (though this would usually result in some grinding noise or other obvious issue other than just faded output).
The device will need to have the technician look at it.
You may call to request Onsite Support at 800-821-2797 if in North America.
Otherwise contact Technical Support for your location.
I can't figure out why my Phaser 6605DN is printing like that :
I've tried many things from the support pages.
Does someone have an idea?