Solution
Step 1: Update printer fimware version

If available, update code to FW5.2, or later. Refer to Downloading the latest Lexmark printer firmware to know how to check, download and update the printer firmware.

Retest.

If the issue is not resolved, proceed to step 2.
Step 2: Perform a re-calibration

Activate by navigating to Settings > Print > Quality > Advanced Imaging > Color Adjust > Start.
Click here to see the steps illustrated.

Retest.

If the issue is not resolved, proceed to step 3.
Step 3: Increase toner darkness setting

To do this from the control panel, navigate to:
Settings > Print Settings > Quality Menu > Toner Darkness.

Retest.
If the issue persists, search for more information related to this issue or contact support for further assistance.