Ask an Expert: Why is my printer printing lines or marks?

For this month’s Ask an Expert, we’re putting another common printer problem to James Benbow. You send a document to print expecting a clean, professional copy, but instead it comes out with lines, streaks, marks or patches across the page. Sometimes it happens suddenly, while other times the print quality gradually gets worse.

James, why is my printer printing lines or marks?

There can be a few different reasons, and the cause often depends on what the marks actually look like and where they appear on the page. It could be something fairly simple, such as dirt or toner on part of the machine. It can also be caused by a worn component, an issue with the drum or imaging unit, or something on the scanner glass if the problem only appears when you’re photocopying.

The pattern of the marks usually gives us a good clue as to where the problem is coming from.

What if there’s a line down every photocopy?

One of the first things to check is the scanner glass. When you use the document feeder, the original document passes over a narrow strip of glass. Even a tiny mark, bit of dust or correction fluid on that glass can create a line all the way down every copy.

It’s surprising how small the mark can be.

How can I tell if the scanner glass is the problem?

A simple test is to print something directly from your computer. If the printed document comes out perfectly but copies made through the document feeder have a line on them, there’s a good chance the scanner glass needs cleaning.

If the line is appearing on everything you print as well, the problem is more likely to be somewhere else inside the machine.

Can I clean the scanner glass myself?

Yes, as long as you do it carefully. Use a clean, soft, lint-free cloth and make sure there isn’t anything stuck to the glass. Avoid spraying cleaning products directly onto the machine.

Pay particular attention to the narrow strip of glass next to the main scanner bed, as that’s often where the problem is.

What causes faded or patchy printing?

That can have a few different causes. It might be related to toner, but it can also be caused by a worn drum, imaging unit or another internal component.

If parts of the page are consistently lighter than others, especially in the same position each time, it’s worth getting the machine checked. Simply replacing the toner won’t always solve a print-quality problem.

What about black marks or repeating spots on the page?

Repeating marks can often point towards a particular component inside the machine. If a mark appears at regular intervals down the page, something rotating inside the printer may be damaged or contaminated.

That’s usually something an engineer will need to investigate.

Can the paper cause poor print quality too?

It can. Damp, damaged or unsuitable paper can affect the way toner transfers onto the page. Paper that has been stored somewhere cold or damp can be particularly troublesome.

Using the correct paper and making sure the machine settings match the paper you’re using can make a real difference.

Should I try changing the toner first?

If the machine is telling you the toner is low or needs replacing, then yes. But if you’ve recently replaced the toner and the problem is still there, repeatedly changing cartridges probably isn’t going to fix it.

If the same marks continue to appear in the same place, there’s likely another cause.

Can print-quality problems damage the printer?

The marks themselves won’t necessarily damage the machine, but they can be a sign that a component needs attention. Ignoring the problem can sometimes mean the print quality continues to deteriorate.

If cleaning the glass and checking the obvious things doesn’t solve it, it’s worth getting somebody to look at it.

When should I call an engineer?

If you’ve cleaned the scanner glass, checked the paper and the problem is still happening, give us a call. It’s also worth getting an engineer involved if you’re seeing repeated marks, heavy streaking, patches of missing print or the quality is getting noticeably worse.

A photo or sample of the affected print can also be really useful, as the type and position of the marks can help us work out what might be causing it.

James, what’s your number one tip?

Look at when the problem happens. If the marks only appear when photocopying, check the scanner glass first. If they’re appearing on everything you print, it’s more likely to be an issue elsewhere in the machine.

Knowing that can make finding the problem much quicker.

Got a question for James?

We’ll be answering more common print and photocopier questions in our Ask an Expert series. If there’s something you’d like James to cover next, get in touch.

hello@weaverbomfords.co.uk
03456 123858