Intermec EasyCoder 501 XP Service Manual page 50

Chapter 8 Print Unit
8.1 Description, cont.
48
The main parts of the print unit are:
• The rubber-coated platen roller drives the media forward under
the printhead and provides the necessary counter-pressure.
• The stepper motor drives the platen roller via one belt and the
ribbon assist roller and the ribbon rewind unit via another. The
liner drive roller is idle, unless a liner/batch takeup kit is fi tted,
see Chapter 9.
• The tear bar makes it easier to tear off continuous and pre-
perforated media stock. It is also used for peel-off (self-strip)
operation.
• The label stop sensor (LSS) controls the media feed and checks
for out-of-paper conditions.
• The printhead produces the heat that melts the "ink" on the
transfer ribbon or blackens the direct thermal paper in patterns
that make up the letters, graphics, or bar codes.
• The headlift mechanism presses the printhead against the media
or transfer ribbon, or raises the printhead to allow media and
ribbon load.
The print unit is a self-contained module and attached to the print-
er's center section by means of four #T20 Torx screws. There are
also a number of cables running from the print mechanism to the
CPU board (see Chapter 15.3), which are not illustrated.
The ribbon rewind unit is driven by a belt from the motor of the
print unit via an idle pulley attached to the inside of the center sec-
tion. The liner drive roller (fi tted underneath the platen roller) may
be driven by a belt to the optional liner/batch takeup stepper motor,
if a liner/batch takeup kit is fi tted. These belts have to be removed
before the print unit can be pulled out.
Intermec EasyCoder 501 XP & 601 XP – Service Manual