Lexmark MS421dn: Setup, Drivers, Ink and Common Problems

Is the Lexmark MS421dn right for you?

The MS421dn steps up from the MS321dn with a higher duty cycle, a 1 GHz dual-core processor and support for the 20,000-page extra high-yield cartridge, which makes it the better buy for anyone printing more than a few thousand pages a month. It is a workhorse with few moving parts beyond the cartridge and imaging unit. Repeated 121.xx fuser codes on high-mileage units usually mean the fuser assembly itself is due for replacement.

Best for: Busy small offices printing 5,000-15,000 mono pages a month

Setting up the Lexmark MS421dn

Use the front-panel Network/Ports menu to confirm DHCP has handed out an address, then open that address in a browser for the Embedded Web Server where you can set a static IP and email alerts for low toner. The Lexmark Universal Print Driver covers this model on Windows; Linux users can use the Lexmark CUPS package or the generic PCL driver. Firmware updates are applied from the Embedded Web Server's Update Firmware page.

1. Unbox and prepare. Remove every piece of shipping tape and packing material, install the toner cartridge and drum unit, and load paper in the tray.
2. Join your Wi-Fi. Keep the printer close to the router for setup. Most printers only connect to the 2.4GHz band, so if your router broadcasts one merged network name you may need to split the bands temporarily. See our Wi-Fi guide if it will not join.
3. Install the setup app. Use Lexmark's official app rather than a driver you found on a search result — third-party driver sites are the most common source of printer malware.
4. Add the printer. On Windows 11: Settings › Bluetooth & devices › Printers & scanners › Add device. On macOS: System Settings › Printers & Scanners › Add Printer.
5. Print a test page and run a scan if this is an all-in-one, so you find any problem now rather than when you are in a hurry.

Ink, toner and supplies

The Lexmark MS421dn uses the following consumables. Match the number exactly when you buy: the same printer family often uses several different cartridge numbers by region.

• 56F1000 Return Program toner (6,000 pages)
• 56F1H00 high-yield toner (15,000 pages)
• 56F1X00 extra high-yield toner (20,000 pages)
• 56F0Z00 imaging unit (60,000 pages)

High-yield (XL) versions almost always cost less per page if you print regularly. On third-party ink and toner, read our honest assessment first, and note that some manufacturers push firmware that rejects non-original chips.

Full specifications