Lexmark C2335/CS531/CS632/CS639 printer platform — 31.60
Lexmark 31.60 means the black imaging unit is not installed or seated correctly. The guidance here is specific to C2335/CS531/CS632/CS639 printer platform and the Black imaging unit operation.
Error meaning
The black imaging unit is not installed or seated correctly.
This interpretation is tied to the reviewed family/platform and subsystem. Do not reuse the code by itself on another printer family.
Applies to
C2335/CS531/CS632/CS639 printer platform
- C2335
- CS531
- CS632
- CS639
Common formatting
These are lookup/formatting aliases for this reviewed condition, not separate pages.
- 31.60
What usually causes it
- The black imaging unit is not installed or is not being detected in its normal position. This unit is separate from the toner cartridge, so replacing black toner alone does not address the condition.
- The exact condition recorded for this code is: The black imaging unit is not installed or seated correctly.
- Using the documented consumable-access procedure, verify that the black imaging unit is present, correctly oriented, and fully seated. Remove any remaining installation material only if the user guide identifies it as packaging.
What to try
Check the condition this code actually names
Reseat the black imaging unit using the normal supply-access procedure.
Isolate the affected part of the workflow
Using the documented consumable-access procedure, verify that the black imaging unit is present, correctly oriented, and fully seated. Remove any remaining installation material only if the user guide identifies it as packaging.
Run a controlled confirmation test
Restart and print a black-text test page. If the message clears, leave the imaging unit seated; repeated removal can create new contamination or handling issues.
After each corrective action
Retry the original operation that produced 31.60. If it works, stop there rather than moving into unrelated troubleshooting.
If the code returns
If 31.60 follows a recently installed black imaging unit, confirm the part is intended for this printer platform and that the same unit is not producing a separate unsupported-supply message.
When service may be needed
Avoid touching sensitive imaging surfaces or opening the unit itself. A correctly seated supported unit that remains undetected requires service.
Continue with guided troubleshooting
If the printer still is not working after the reviewed checks, carry this verified error context into the guided troubleshooter.
Related information
Verified source
Official four-model User’s Guide (2026 edition) contains the printer error-code section and safety cautions.