I've had similar problems when a dust speck or hair or clump of dried ink got caught on the print head and interfered with the path of the ink droplets from the print head to the paper. Think of a hose spraying water in a stream at a wall, and then a stick is placed in the water stream, causing it to splash all over the wall instead of hitting a small part of the wall. You have the same kind of thing happening here, just on a smaller scale.
Try putting the printer in cartridge change mode, so the print head is parked in the middle of the page instead of on the side, then unplug the printer so it stays there. Then take a sheet of paper and fold it so that it fits inder the print head, but somewhat tightly because the head is rubbing on the paper a little. Then move the paper back and forth to rub the debris off the print head. Remove the folded paper, plug the printer back in, then turn it on and do a test print. Hopefully that will fix the problem.