Lexmark CX725
Remove the front cover. See Front cover removal.
Remove the two E-clips (A), and then remove the shaft (B).
Lexmark CS/X72x and C/XC41xx: Print Quality Diagnosis ? Light Print on Printed Page Colors
Lexmark CX/CS8xx_72x and XC/Cxxxx: How to use the Lexmark Scan Center functions found in the 2016 Lexmark printer common utilities package