Updated 20/05/2019

Is your printer leaving black lines down the page when you print?

Black lines down the page when you print can be very frustrating when you’ve got an important job or presentation to do, especially if you’re running low on time.

Before you decide to go postal on your printer… you aren’t alone! This is one of the most common printer issues that many people experience and normally happens when you need your printer the most and the good news is, it can be fixed!

But what on earth causes your page to look like the monstrosity above? If this is happening with your Brother, Canon, HP, Lexmark, Oki or Xerox printer and you’ve had enough then read on….

Here’s what you’ll learn about printers & black lines

  • What causes black lines or smudges down the page
  • How to fix the printing black lines issue
  • What causes horizontal lines on a printer / how to fix it
  • What’s the deal with faint or missing lines? And how to fix it.


What causes black lines or smudges down the printer page?

So, there are several possible reasons that your printer might be causing black lines or smudges down the page when you print your important document and we’re going to address each one in turn in a process of elimination to help you to fix your problem.

Here are some of the different printer problems:

  1. Black lines or tracks down either side of the page, sometimes in the middle.
  2. Missing areas of print (either always in the same place or not).
  3. Smudges on the page (either always in the same place or not).
  4. Horizontal lines across the page.

If you’ve experience any of these problems, here’s an example of what your prints might look like:


Horizontal lines on a printout:


Horizontal lines caused by an inkjet printer


Here’s why it happens, & how to fix smudges or lines down your printout. First, run a printer clean process to see if it’s a quick fix, you’d be surprised how many times that works. If it didn’t try the following:


Black lines or tracks down either side of the page.


Inside the printer the paper is moved along by rollers and often a piece of film like a conveyor belt (called a transfer belt). This happens when the rollers or the transfer belt inside the printer get dirty or covered in excess toner powder and as the paper is moved through the printer, the ‘tracks’ are being left on the page.

This is normally the case when the tracks on the page are located at either end. If the tracks are located all over the page or even in the middle, it could be due to marks or damage to the transfer belt.

Also, if a blob of dirt or old toner is stuck to a roller or the transfer belt, it smudges a line down the paper as it passes.


The following steps will help to fix this issue:

  1. Get a lint free cloth, rubber gloves (so toner doesn’t get on your hands), some isopropyl alcohol, and a soft paint brush and gently clean any rubber rollers you can easily reach.
  2. With a vacuum hoover out any loose toner particles.
  3. With a lint free cloth very gently wipe the transfer belt (not all printers have one).
  4. If all else fails, you may need to replace the transfer rollers / transfer belt.

Warning: make sure you wear gloves and don’t touch the transfer belt film with your fingers or the hoover, you could leave a mark that will cause additional print problems.

Remember to be careful and if you are at all unsure, find a printer technician who is experienced in cleaning the printer.

Missing areas of print (either always in the same place or not)


There are a few possible causes of this so you may need to check each in a process of elimination to figure out what’s happening but in most cases, the problem is caused by the drum.

The laser printer works by a laser beam ‘sketching’ the image of what you are printing onto a green metal cylinder called a drum or photoconductor unit. This drum then rolls the toner onto the paper as it passes. A drum is a replaceable maintenance part of the printer and can either be built into the toner cartridge, or separate from the toner located on top of or underneath it.

If the drum is damaged in any way with a finger print or dirt on it, it can cause sections of the print out to be missing because the dirt is blocking your image from being rolled on to the page.

It can also be caused by a damaged or dirty mirror that reflects the laser beam or it can be caused by a damaged fuser unit.

The fuser is a replaceable maintenance part in the printer that melts the toner so it stays on the page. It also applies pressure so if some part of it is damaged, it can stop the toner from staying on the page.


Unfortunately, these maintenance parts can’t easily be cleaned but the following steps may help to fix this issue:

  1. Replace the toner if you have a new one spare, it could be defective or running out.
  2. Replace the drum unit – this will fix the problem most of the time.
  3. Replace the fuser unit.

Warning: Never touch the green metal cylinder (drum unit)

Once again, remember to be careful and if you’re not sure, get some help.

Smudges on the page (either always in the same place or not)


If you see smudges across your page and they are always in the same place, then that normally indicates some damage to either the drum or the rollers (see problem 2 above for a definition of the drum). It could also potentially be a roller.

What’s happening is that the drum or rollers could have a fingerprint or dirt that is smudging the toner on the page as it passes through to the fuser. It is normally caused by the rollers.

If the marks are always in different places, then its most likely to be the drum.


Have a look inside the printer and see if you can spot any dirt on the drum or any of the rollers that might indicate a problem. Follow the steps below in turn and do another print before the next step to eliminate the problem.

  1. Clean the rollers
  2. Replace the toner if you have a new one spare, it could be defective or running out.
  3. Replace the drum unit.
  4. Replace the fuser unit.

Be careful and again if you’re not sure, get some help and don’t forget your gloves so you don’t get toner on your hands.

Horizontal lines on an inkjet printout


For laser printers, this is normally the same solution as the ones above so try each and see if they help fix the issue.

If you have an inkjet Printer:

Inkjet printers (that use liquid ink), work totally differently than laser printers (that use powdered toner) but we still get the same issues. So if you have horizontal lines on an inkjet printer, it is normally caused by a blocked or clogged print head.


Firstly try the print head cleaning option in the printer menu. If that doesn’t work, then get some paper towels, cotton buds (Q-tips) and warm soapy water. Take the ink cartridges out, switch the printer off / unplug it. Take the cartridge and place it on the paper towel, then check where the ink comes out. If it looks clogged, use a damp (not soaked) cotton bud to dab and clean the print head. Sometimes the print head is part of the cartridge carriage, if so use the cotton buds to try to clean the area where the ink comes out but don’t get the printer wet!

This should fix the issue once you reinsert inks and try to print again.

What’s the dealio with missing lines down the printout??

 baby confused idk unsure good luck charlie GIFYou may be mucho unimpressed with my focus on black smudges and lines down the printout but what about when your printer spits out a page with faint or even missing lines down the page??

This is a less common issue which is why I didn’t focus on it but don’t worry, I’m here for you too!

Faint or missing lines down the page is normally caused by the cartridge not having the seals removed fully or something being stuck to the rollers or drum unit that’s blocking off a line of toner or ink as it attempts to print.

You can normally fix that by doing the following:

  1. Check the drum, print head, ink cartridge or toner cartridge for seals that should have been removed when it was installed or even sticky blobs left behind.
  2. Run a printer clean.
  3. Replace the drum or toner cartridge.

Try each of the above steps in turn and then print after each to eliminate the problem rather than do every step before you print.

 success borat great success GIF

Hopefully any of the solutions listed in the different types of problems with print above will have fixed your frustrations, but if none of the above steps work then it could well be a much more serious problem with your printer and it might be time to think about a new one!

Kazar! We can help you with that if you’re in the UK as we do sell printers. Let me know in the comments below and I’ll be happy to help!


Did this article help you out? Were you mucho impressed or super disappointed with my ample genius? J Let me know in the comments, or if you just want to ask anything else, get in touch and comment below!