What is the Difference Between a Toner Cartridge and a Drum Unit?

While shopping for toner cartridges, you may have noticed that some printers take a toner cartridge and a drum unit as well. But what exactly is the difference between the two, why do they have different page yields and which one do you need to buy?
What are Toner Cartridges?
Toner cartridges are fairly simple pieces of equipment. They are essentially a plastic casing that contains the toner powder. Some toner cartridges do come with the drum unit combined as a single unit, like the HP 12A black toner. Simple ones, like the Samsung 406 black toner need a separate imaging drum unit in order to print. The images below show the difference between the two types of toner cartridge:
What are Drum Units?
Drum units, like the Brother DR-2255 drum unit, are complex pieces of equipment and this is where the printing mostly happens. Inside the drum unit you will find the photo-sensitive drum and the corona wire. A laser writes the image or text onto the drum and alters the electric charge wherever it makes contact. The drum is then rolled through the toner which is picked up by the charged portions of the imaging drum. Finally, toner is transferred to the paper using heat and pressure. The image below is an example of a drum unit.
In the case where you need to use a toner cartridge and a drum unit, the two items will be sold separately. The toner cartridge slots in to the drum unit and the drum unit goes into the printer.

So why do drum units and toner cartridges have different page yields?
Toner cartridges contain a finite amount of toner powder, so they can only print a limited amount of pages. A drum unit usually only needs to be replaced after about 3-4 toner cartridges have been replaced, some drum units can last a little longer. For example, the Brother TN-2060 toner cartridge can print an estimated 1200 pages while the drum unit it works with, the Brother DR-2255, is good for 12 000 pages. That means that you will only need to replace the drum unit after replacing about 10 toner cartridges.

Which one do I buy?
Generally, your printer will let you know if the toner cartridge or the drum unit needs to be replaced. If your printer doesn’t let you know that the toner cartridge or drum unit needs to be replaced, you can check the quality of the prints. If the prints you are getting are faded, you will need to replace your toner cartridge. If you are getting blank spaces or streaks in your print, you will need to replace the drum unit.

The best way to determine whether your printer needs a separate drum unit is to check the user manual. The user manual will usually have a list of which printer consumables you need. All Brother tonerOKI toner and Xerox toner printers have a separate drum unit and toner cartridge, while only some Samsung tonerHP tonerCanon toner and Lexmark toner printers will need you to buy both.

If you’re still in doubt, you can always contact us.
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