Datamax DMX E E-4204 Operator's Manual page 14

Present Sensor
The Present Sensor allows the printer to be configured for "one up"
printing. With the sensor installed, the printer will not print the next
label until the previously printed label has been removed from the
printer.
Thermal Transfer
The Thermal Transfer option allows the printer to use ribbon. The
ink/wax from the ribbon transfers to the media to create an image
with exceptional clarity and scanability.
4 E-4203/E-4204/E-4304