31.01CS421dn

Lexmark CS421dn error 31.01: Causes and Fix

The Lexmark CS421dn error 31.01 is a paper jam warning localized in the tray pickup area. This error triggers when the rollers attempt to move the paper but the pass-through sensor fails to detect the document in time. It is common if paper is misaligned or damp.

1 views

Common causes

  • 1Damp paper causing sheets to stick.
  • 2Pick rollers worn out from heavy use.
  • 3Misadjusted tray guides.
  • 4Sensor obstruction from accumulated toner dust.

Solutions

Quick Diagnosis

If the error appears without visible paper, the tray sensor might be blocked by a tiny particle or paper scrap.

Step-by-Step Solution

  1. Turn off the printer.
  2. Remove the paper tray and check the condition of the pick roller.
  3. Use a flashlight to inspect the path behind the tray.
  4. Reinstall the tray, ensuring paper is correctly adjusted in the guides.

Prevention and Maintenance

Fan the paper before loading to separate sheets. Keep the device in a low-humidity environment to prevent paper from sticking.

When to Call a Technician

If rollers spin but do not pick up paper even with a new load, the feed motor might be failing.

Equipment Datasheet

  • Technology: Color Laser
  • Speed: Up to 35 ppm
  • Connectivity: USB, Ethernet
  • Compatible consumable: 50F series toner (CS421dn)
  • Official drivers / firmware: https://www.lexmark.com/support

Steps to follow

  1. 1

    Tray Removal

    Remove the input tray completely from the device.

  2. 2

    Visual Inspection

    Look for torn paper fragments in the roller area.

  3. 3

    Reset

    Reload paper and close the tray firmly.

Frequently asked questions

By clearing any paper obstruction in the feed area.

It indicates a paper sensor is not detecting correct advancement after feeding from the tray.

Use standard 80g paper; very thick stocks can cause this error.

Yes, clean them every 10,000 prints to prevent slipping.