A toner cartridge and a drum unit are both essential components of a laser printer, but they serve different functions.
A toner cartridge contains the toner powder, which is a fine, dry mixture of plastic particles, carbon, and coloring agents. This powder is used to create the text and images on the paper. When you print, the laser printer uses an electrostatic charge to transfer the toner from the cartridge onto the drum unit.
The drum unit, on the other hand, is a cylindrical component that transfers the toner onto the paper. It receives an electrostatic image from the laser, which attracts the toner particles. As the paper passes through the printer, the drum unit rolls the toner onto the paper, and then the paper goes through a fuser unit that melts the toner, permanently bonding it to the paper.
In many printers, the toner cartridge and drum unit are separate components, allowing you to replace them individually. This can be cost-effective, as the drum unit typically has a longer lifespan than the toner cartridge. However, some printers use an all-in-one cartridge that combines both the toner and the drum unit, simplifying the replacement process but potentially increasing costs over time.
In summary, the toner cartridge supplies the toner powder, while the drum unit transfers the toner onto the paper. Both are crucial for the printing process, but they have distinct roles and lifespans.