Drum Units Explained: Function, Maintenance, and Replacement Tips

A drum unit (sometimes called an imaging drum or photoconductor unit) is a light-sensitive aluminum cylinder coated with an organic photoconductor layer. During each print cycle, the laser discharges points on the drum surface, forming an invisible “map” of your page that later attracts toner.

1. Charge - A corona wire or charge roller gives the drum a uniform electrical charge.
2. Write - The laser sketches the image, neutralising selected areas.
3. Develop - Toner clings to the discharged areas on the drum.
4. Transfer - A stronger, opposite charge pulls the toned image onto paper.
5. Clean & Erase - A wiper blade removes stray toner and a discharge lamp resets the drum.

• Image quality gatekeeper - A worn drum causes ghosts, gray background, and blurred text.
• Cost control - Separating drum and toner can cut cost-per-page for high-volume fleets.
• Longevity of other parts - Clean drums shed less waste toner, helping the fuser and transfer system last longer.

When storing spare drums, keep it dark by leaving them in the original foil bags, as light quickly degrades the photoconductor. Oils from your skin can permanently mar the drum surface, so handle the cartridge carefully and avoid fingerprints. To maintain proper charge characteristics, remember to control humidity in the storage or print area. Finally, once a new drum is installed, be sure to reset the drum counter so the printer can track maintenance accurately.

• Repeating dots or streaks every 2–3 inches
• Gray haze over the entire page
• Sharp black spots or horizontal lines
• Printer alert saying “Replace Drum”

• OKI B411 OEM Black Drum, 30,000: (Part Numbers: 44574301)
• OKI MPS5501mb OEM Image Drum, 72K: (Part Numbers: 45456301, 45456306)
• OKI ES5112 OEM Black Drum Unit, 30,000: (Part Numbers: 44574317)

• How to replace the Drum Unit for Canon imageRUNNER ADVANCE C5030
• End of Life Error: Xerox C310 and C315 Black and Color Imaging Kit Replacement
• How to replace the Drum Unit, Waste Toner Cartridge and Toner Cartridge for Canon imageRUNNER 1730, 400IF

The drum unit converts digital data into physical images thousands of times a day. Treat it with care, replace it at the first signs of wear, and pair it with quality toner to keep your documents crisp and your maintenance costs predictable.

Our experts can help you find the right drum unit for your device.