Lexmark MX953, CS963, CX950, 951, 961, 962, 963, 833, XC9525, 9535, 9635, 9645, 9655, 8355 Black Imaging Unit (77L0Z10) – 225,000 Pages

The toner cartridge holds the powder that forms your print; the drum — also called the imaging unit — is the roller that transfers it onto the page. They're separate consumables, and a drum typically outlasts several toner cartridges.

Faded prints, repeating marks or streaks running down the page, or a replace-drum message on your printer are the classic signs the drum's coating is worn.

Check the rated yield on this page — many drums are rated for 12,000 to 20,000 pages or more. Actual life depends on how you print: frequent short jobs wear drums faster than long black-and-white runs.

Many printers track drum life with a counter — reset it through your printer's settings menu after installing the new drum so it measures the new unit accurately. Your printer's manual shows the exact steps for your model.

Yes — drums are user-replaceable by design. Open the printer's front cover, remove the old drum, slide in the new one and close the cover. No tools or technician needed.