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Drum Units vs. Cartridges – What’s the difference?

By Simon Williams
November 29, 2018

If you’ve owned or used laser printers for sometime, then you may already know what the implications are of drum units vs. toner cartridges. This would be especially true if you’ve been handling the maintenance of your laser printers yourself. However, drum units vs. toner cartridges is something that most users of laser printers can’t wrap their heads around, so in this blog we’ll simplify the comparison by explain the key differences between the two.

Toner Cartridge vs. Drum Units

While both of these components are vital to producing a print, it’s often a common misconception that toner cartridges and drum units are the same thing – although they’re not. In short, the toner cartridge is a container that contains the toner powder, whereas the drum unit is an electrically charged cylinder that transfers the powder onto paper. Without a drum unit, the toner powder is unable to be transferred onto a piece of paper, which is why both parts are essential components for producing a print.

Which Should You Replace?

While both the toner cartridge and drum units are essential for printing onto a piece of paper, although you may not have physically come into contact with the drum unit. The replacement of a drum unit will largely depend on the design of your printer, since a drum unit and toner cartridge may be combined unit or sold separately as a single unit. Overall, this may be different from printer to printer, as the consumable requirements of the printer can vary from brand to brand. As such, while some printers simply need you to replace the toner cartridge, others may require a full replacement of both the toner cartridge and the drum unit.

Printer brands such as HP and Brother are typical examples of how different brands incorporate both toner cartridges and drum units into their products. For example, HP laser printers generally have the toner cartridge and drum unit combined as one unit, whereas Brother’s laser printers employ a separate toner cartridge and drum unit.

When Should They Be Replaced?

Printers with separate drum units generally last longer than a toner cartridge, so you should look to replace the unit when you have replaced the toner around 3-4 times. However, your printer should notify you when you when its time to change your drum unit, although you can normally tell when it’s time to change as you’ll notice black spots or lines being printed across the page. Similarly, you should be able to tell when your toner cartridge has run out as you’ll be unable to actually print anything, since there’s no toner left in the cartridge.

Which Is Better?

All in all, there is little noticeable difference in performance, as both variations of toner and drum unit set ups work just as well as the other. Ultimately, though, the main point of difference regards cost, as the prices of the two setups can vary significantly – especially if you’re continually buying replacements for your business. Toners that are combined with the toner unit are typically more expensive than ones that are sold separately, since you’re essentially replacing both the cartridge and drum unit whenever you run out of toner.


In short, both toner cartridges and drum units are essential components that enable a printer to produce a print. Consequently, when you run out of toner, the parts that will need replacing will depend on the brand and set up of the printer. In some printers, only the toner cartridge will need replacing, but in others you’ll need to replace both the drum unit and the toner cartridge each time. Naturally, the cost implications are greater when replacing both, so you should consider buying only what you need, rather than stocking up.