There are very few things that can go wrong with laser printers and toner cartridges. One of the few issues commonly experienced is ‘ghosting’, when light images from previous print jobs appear on newly printed pages.

Ghosted images are usually lighter than the fresh text and images on the new page and can make your print look messy and unprofessional. But what causes ghosting and can it be fixed? Our technical team have put together this guide to answer your questions.

What causes ghosting?
The most likely culprit is either the imaging drum unit or the fuser unit, however humidity and the incorrect paper type can all play a role in ghosting.

Ghosting is often caused by a malfunctioning imaging drum unit. When a drum unit comes to the end of its useable life cycle, it may not discharge properly, leaving behind faint traces of the previous printing job. It may also be that the drum unit is defective and is not discharging correctly between print runs. Fuser units can also cause ghosting. If a fuser unit is not heating the toner powder correctly, ghost images can appear when printing.

You can check to see if the fuser unit or drum unit is causing the ghosting by having a look at the ghosted images. If the images are fairly close together (between 2cm and 3cm), the ghosting is most likely being caused by the drum. If the ghost images are further apart (between 4cm and 5cm), the likely culprit is the fuser unit.
Most printer user manuals also come with a ‘diagnostic ruler’ on the back page. You can use this ruler to pinpoint the source of the ghosting by comparing the marks on the ruler to the marks on the page. 

Humidity can affect the toner powder inside a toner cartridge. If it is too humid, the toner powder may clump inside the cartridge. When this happens, the toner powder does not get distributed evenly when printing, which can lead to ghost images on the page.
Because of the heat and pressure used in laser printing, pre-printed paper can also cause ghosting as the printed image can be transferred during the fusing process. If the paper is too thick, glossy or not designed for laser printing, ghosting will most likely occur.

Dust and debris inside the printer can also cause ghosting as too much dirt can interfere with the drum units, transfer units and fuser units.

How can I fix ghosting?
If the drum unit is the cause of the ghosting, check to see that it has not reached the end of its useable life. If the drum unit is separate from the toner cartridge (like most Brother toner and some Samsung toner cartridges), the printer will usually have an error message asking you to replace the drum unit. If the drum unit is built in to the toner cartridge (like most HP toner cartridges), check to see if the toner cartridge needs to be replaced.

However, if the drum unit is either new or built in to a new toner cartridge, the drum unit is most likely faulty. Contact the place you purchased the toner cartridge from and ask them to replace the faulty cartridge.

If the ghosting is caused by the fuser unit, you’ll most likely have to take your printer to an authorised repair centre to get it serviced and have the fuser unit replaced. It could also be that your fuser unit is too hot. Check your user manual to see if you can adjust the temperature of your fuser unit.

If you suspect that paper may be the cause of ghosting, make sure you are using paper that has been designed for use in laser printers. You can also adjust your paper settings if you’re using thick or glossy paper for laser printers.

If you’re using pre-printed paper, make sure that has been printed with laser printer compatible printer ink. You can ask the manufacturer or check the packaging to make sure it’s been manufactured for use in laser printers.

If humidity is the issue, make sure you store your toner cartridges in a cool room with low humidity. This also has the added benefit of making sure your toner cartridge lasts a little longer. You should also clean the outside of your printer regularly to make sure dust and debris don’t get inside the printer.

Some printers also come with a cleaning cycle that makes sure that excess toner powder does not stick to the drum units. Check to see if you can run a cleaning cycle or print a cleaning page to get rid of excess toner.

Make sure that all the power cables are undamaged and plugged into the printer correctly. If there is a problem with the power cable, this could be affecting the way the fuser unit heats up or the way the drum unit holds electric charge.

If you have any questions about how to solve ghosting, please feel free to contact us.