How to Fix Printer Printing Horizontal Black Lines?

May 23, 2026 3 min read 18,064 views

To resolve the issue of horizontal black lines printing you need to first find the exact reason behind this problem. There can be two possible reasons why this is happening: the first is a problem with the optics and the second is the problem with the drum.

The optic problem arises when there is some type of material on the top of the glass due to which the scanning is not being done properly and it's blocking the clear view of the image. You can solve this problem by simply cleaning and keeping your equipment clean. The problem with the drum arises when the drum gets damaged. You can fix the problem by replacing the drum.

Why is My Printer Printing Horizontal Black Lines?

If your printer often prints a document with horizontal black lines, then you must first find out the root cause of the problem. There can be two reasons why horizontal black lines appear on the document.

Printer Printing Horizontal Black Lines

Solution 1: For Printer Printing Horizontal Black Lines

If you are seeing black lines on the copies and not on the prints, then that means there is some problem with the optics. This means that there is some material on top of the glass where the scanning is done. Hence, there is something getting in the way of the machine that is blocking it from getting a clear view of the image.

why is my laser printer printing horizontal black lines

If your laser printer machine is forming horizontal lines on the copies and not on the prints, then your problem can get solved by simple cleaning. Even a little bit of debris on the optics can lead to the problem of defective prints.

Therefore, it is necessary to keep your equipment clean. The silver lining is that this solution is comparatively easier to carry out. Moreover, it is affordable as you do not require to replace anything. The next solution is more complicated in comparison to this one.

black horizontal lines when printing

Solution 2 : For Printer Printing Horizontal Black Lines

If your printer is printing horizontal black lines on copies as well as prints, then that means the problem lies in the drum. A drum is a photoconductor or camera that takes a picture. The drum inside your printer is a very delicate part and if it gets damaged, then you will see its impact on every print and every copy you create.

In some cases, the drum gets repaired but mostly they have to get replaced. Consider it like replacing car breaks. Hence, every part of the equipment will require repair and maintenance.

Summing up, when your printer machine prints horizontal black lines, it can be either because of the drum issue or optics issue. To resolve these two issues, you need to clean the optics or replace the drum to fix the problem.

what causes horizontal black lines when printing

If the problem of printer printing horizontal black lines still remains even after cleaning up the optics or you are not comfortable in replacing the drum of the machine, then contact the customer care experts to fix your problem. The experts will diagnose the problem and provide you with the most appropriate remedy to fix the problem that you are encountering.