Datamax H-4212X Operator's Manual page 28

E. If loading media for the first time, or when switching media types, widths, or
configurations, position the Media Sensor as detailed in Section 3.2; otherwise, go to
Step F.
If loading thermal transfer media, also load ribbon; see Section 3.3.
F. Lower the Printhead Assembly then rotate the Printhead Latch completely clockwise.
G. Close the cover. With READY displayed, press and hold the FEED Key until at least one
gap (or mark) advances; see Section 3.4.
If your media is less than the full width of the platen, adjust the Leveling Cam;
see Section 5.4.1.
18 H-Class