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

Laser printers, ranging from small desktop units to workgroup-class machines, can provide your company with years of trouble-free output. When your trusted hardware begins to produce pages with vertical or horizontal lines that aren’t part of the content you printed, start with simple possibilities before assuming the worst. Correlating the symptoms you see with the suspects that can cause them can help you narrow down the source of these defects.

Roller Tracks
When toner leaks from a cartridge and into your printer’s mechanical assemblies, it can contaminate the rollers that move paper through the machine. The “tire-tracks” pattern produced by this contamination appears at the sheet’s edges or centre and corresponds to the location of the rollers relative to the paper-feed path. Unless you are a printer technician, leave this task to the professionals, especially if your hardware is still under warranty. However, before calling for service, replace your toner cartridge (or cartridges in a colour printer) to rule out defective supplies.

Vertical Streaks or Lines
Depending on whether you see black or white vertical defects – printed marks or voids in the printing – you may be dealing with nothing more serious than a nearly empty toner cartridge, one with a scratched drum, or toner that is not evenly distributed. Changing the cartridge should help you rule it out as the culprit. Vertical white lines can also indicate an obstruction that prevents the laser from properly imaging pages. To resolve the issue, the laser assembly may need to be cleaned or replaced entirely.

Horizontal Lines
Horizontal printing flaws and marks that appear at regular intervals can be caused by contaminated rollers. Manufacturers provide model-specific repetitive defect rulers that can be used to correlate the position of the defects on the page with the layout and size of the rollers, cartridge components, fuser parts, and other potential causes of non-random markings. Dropouts and non-repeating marks can be caused by the same issues as vertical defects, such as laser contamination and toner cartridge malfunctions.

Considerations
Toner cartridges are the most commonly replaced parts in laser printers. Light damage their drums and jeopardises print quality. Contaminants introduced through the paper supply may also cause scratches that obstruct proper imaging. Because print defects can occur at any time, having spare cartridges on hand allows you to resume work immediately if your consumables fail. Many of the other potential causes of lines and streaks on your output, particularly lasers and fusers, can endanger the well-intentioned but inexperienced. Set down the tools and delegate the work to an expert if you are unsure of what you are doing under the lid.