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What This Error Means

Lexmark Error 21 indicates a paper jam has occurred, specifically detected in the output bin area or within the duplexing mechanism.

Detailed Explanation

Lexmark Error 21 is a common paper jam message that points to a paper path obstruction after the fuser unit, typically as paper exits into the output bin or during its journey through the duplexing assembly for two-sided printing. This error means the printer detected paper entering a sensor but failed to detect it exiting a subsequent sensor within the expected timeframe, or detected paper where none should be. The most frequent causes include improperly loaded paper, damaged paper, foreign objects obstructing the paper path, or issues with the duplexing unit's rollers or flappers. While often a simple fix, persistent Error 21 can signal underlying mechanical problems. It's crucial to distinguish between a simple paper obstruction and a component malfunction. A piece of torn paper, a staple, or even a misaligned output tray can trigger this error. If the error occurs consistently, even after clearing visible jams, it might suggest worn rollers, a faulty sensor, or a problem with the duplexing motor or gears, requiring a more in-depth diagnosis.

DIY Troubleshooting Steps

Try these steps before calling a specialist

1
Turn off the printer and unplug it from the power outlet to ensure safety before proceeding.
2
Carefully open all access doors, including the front cover, rear cover, and any side panels that provide access to the paper path.
3
Gently look for any visible pieces of paper, torn fragments, or foreign objects (like staples or paper clips) in the output area, around the fuser exit, and within the duplexing unit (if applicable).
4
If you find jammed paper, slowly and carefully pull it out in the direction of the paper path. Avoid tearing it, but if it tears, ensure all small pieces are removed.
5
Check the paper tray to ensure paper is loaded correctly, not overfilled, and that the paper guides are snug against the paper stack without being too tight.
6
Close all covers securely. Ensure they click into place, as some printers will not operate if a cover is ajar.
7
Plug the printer back in and turn it on. Allow it to initialize and see if the error clears.
8
If the error persists, try printing a test page from the printer's menu to see if the jam recurs.
9
Consider cleaning the paper path rollers with a lint-free cloth lightly dampened with water or isopropyl alcohol, especially if you suspect worn or dirty rollers are causing misfeeds.

When to Call a Specialist

If you have thoroughly followed all DIY troubleshooting steps, cleared all visible obstructions, and the Lexmark Error 21 persists, it's time to contact a specialist. This typically indicates a deeper mechanical or electronic issue, such as a faulty paper sensor, a worn or damaged roller in the output or duplex path, or a problem with the duplexing unit's motor or gears. Attempting to disassemble the printer further without proper training could cause more damage. A professional technician has the tools and expertise to diagnose and repair these internal components safely.

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LEXMARK Error Code 21