What Are the Causes of Lines on the Page From a Laser Printer?

Your office's laser printer is a very complicated piece of technology. As such, there are a number of different systems in the printer that can malfunction. However, in many cases, these malfunctions do not stop the printer from printing, but rather impact your printouts' quality by causing the printer to leave black or white stripes on the pages.

Dirty Corona Wires

Depending on the design of your printer, the corona or corotron wires may be located on the toner cartridge, on the imaging drum cartridge or somewhere below the paper path. They are very fine wires that emit electrical charges to wipe the imaging drum clean or charge the paper so that toner sticks to it. When they get dirty, it can prevent charge from being applied to the paper or the drum, creating fuzzy white lines.

Dirty Developer Unit

The developer is the part of the laser printer that transfers toner from the receptacle in the cartridge to the imaging drum. If there is a blockage in the assembly, it can prevent the developer's roller from picking up toner and depositing it on the drum, leaving a crisp white line. Since many printers have the developer in their cartridges, you may be able to fix this by removing and shaking the cartridge. Replacing the cartridge should also fix the problem.

Fuser Unit Issues

The fuser is the final assembly in your laser printer -- it contains a series of heated rollers that melt the toner onto the paper and eject it to the output tray. A failing fuser can cause black or white lines that are horizontal or vertical. While you can clean fusers on some printers, on others you cannot and therefore have to replace them.

Print Cartridge Issues

The consumable parts of your print cartridge can also cause lines on your page. Faded areas can be caused by low toner levels, while a dirty drum can cause vertical lines on the page. As with developer issues, removing and shaking your cartridge may solve these problems. Some problems can also be caused by your cartridge getting slightly unseated in the printer. As such, you may not need to replace the cartridge -- simply reinsert it to see if that solves the issue.