These types of lines are typically caused by dirt or white out (correction fluid) on the scanner unit, or one of the corona wires for printing is dirty. This problem is usually resolved by cleaning the scanner glass, scanner glass strip and white plastic bar with a soft lint-free cloth, or cleaning the corona wires.

Please refer to the instructions, "How do I clean the scanner to improve the copy or fax quality?" and "How can I clean the corona wires?"