Lexmark CX725
Remove the top frame cover. See Top frame cover removal.
Remove the top frame base cover. See Top frame base cover removal.
Remove the diverter. See Diverter removal.
Remove the screw (A).
Remove the retainer (B), and then remove the sensor from the bracket.
Lexmark Scanner Technology Comparison of Lens Reduction Scan Module (LRSM) and Contact Image Sensor Module (CISM)
Lexmark CS/X72x and C/XC41xx: Print Quality Diagnosis ? Light Print on Printed Page Colors