Affected Products:
Single function: CS820, & C6160
Multi function: CX820, CX825, CX860, XC6152, XC6153, XC8155, XC8160, XC8163.

Issue Description:
Within these given printing parameters:
Heavy media; i.e., cardstock (>200gsm; 110lb index)
Black-only mode
Multiple pages (Not seen on first page)
A black or darker shaded horizontal band appears, positioned ~52mm from the lead-edge of the sheet.
Samples

Solution:

Add spot color to force the printer into color mode.

Add a short delay between the prints.

Switch to a lighter weight (bond) media.

Still Need Help?
Have the following available when calling Lexmark Technical Support;
Printer model(s)
Printer serial number
LEGACY ID: SO8302