Hello-
I see from original post that this does happen when copying also. So i would tend to agree that it is not a driver issue. i'll include this link for print quality :
check the print quality page, and also perform a cleaning of the ink cartridges. You should be able to find this if you hit the wrench button the front panel of the printer, go to tools and find "clean cartridges". Normally the printer does "self" maintenance to keep the nozzles healthy.
Does the issue clear up when you install new ink ??
Also , make sure to power the printer down with the power button, as this make the carriage "park" in the service station and cap the ink. I hope this helps.