This is a very common issue, which can be fixed relatively quickly. Lift the lid of the Machine as though you are going to make a copy from the Main Copy glass. To the direct left of the Main Glass, there is a skinny piece of glass running parallel, known as the Slit Glass. With a clean soft cloth, clean this strip of glass. Typically, as paper passes this Slit Glass it leaves residue, such as white out or tape on this glass causing lines. If the problem persists, add alcohol or glass cleaner to cloth, clean and test again. For extremely suborn and hard to see “spots”, align the print out with the line on the main glass, this will highlight on the slit glass the “spot”.