What is the Difference Between a Drum and Toner?

Whilst the differences and benefits may not be apparent at first glance between a drum and toner, once you understand a little better how they’re different, it will help you to understand the replacement and maintenance of these consumables.

Generally, modern laser printers contain both the drum and toner and some house the toner and drum within a single unit. However, some manufacturers like Brother keep these two components separate.

The benefits to this is being able to replace the components individually if your toner runs out or the drum unit becomes damaged. However, if the two components are housed together and one or the other needs replacing then the whole unit will need replacing.

How Do They Work?

original drum and toner

The drum unit transfers the toner to the paper. It is an aluminium cylinder with a photosensitive coating and when you press ‘print’ the surface of the drum receives a static charge and the laser scans an image onto its surface. The drum then turns and picks up toner from the cartridge to make the image and this is either rolled directly onto the paper passing underneath or a charged transfer belt, which takes the image to meet the paper at a later stage and finally, through the fuser which bakes the image on to the paper.

Manufacturers use different descriptions for the drum such as Photoconductor Unit, Imaging Drum and Print Unit.

Generally speaking, a toner cartridge contains a dust-like powder that fuses onto a page to create your prints.  The drum is combined in the same cartridge as the toner. Where supplied separately, the toner cartridge is basically a container for the toner and a roller for supplying the toner to the image drum.


In terms of replacing these consumables, combined drum units and toner cartridges will cost more than individual toner cartridges as you might imagine, but it doesn’t cost as much as a single drum unit.

Individual drum units tend to outlast two or three toner cartridges. This means that if the components are kept separate then you can change the toner without having to unnecessarily replace the drum unit when it’s not needed. But of course when the drum unit does need replacing, this cost comes at a higher price than the replacement of a combined unit. As you move up the price bracket you’ll find that the drum units and cartridges are kept separate anyway to accommodate not having to unnecessarily replace individual components.

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