Stepper Motor - Intermec EasyCoder PF2i Service Manual

Chapter 7—Print Mechanism

7.3 Stepper Motor

Description
Replacement
80
The stepper motor drives the platen roller and the liner drive roller using
a double-belt pulley and two timing belts inside the electronics compart-
ment. It also drives the optional liner takeup unit using a pulley on the
opposite side of the motor and a long belt that runs inside a recess in the
center section. The pulleys are permanently fi tted and cannot be replaced.
The stepper motor is driven in micro-stepping mode with 8 steps/dot at 8
dots/mm (203.2 dpi), which means that the theoretical feed error will be
negligible. However, mechanical conditions such as a worn platen roller or
a slippery liner may adversely affect the accuracy.
The stepper motor is fi tted using four #T20 Torx screws and rubber noise
dampeners inside a moulding protruding from the center section.
Replace the stepper motor as follows:
• Switch off the power and disconnect the power cord.
• Remove the front/left-hand cover, see Chapter 3.2.
• Disconnect the stepper motor cable from P10 on the Power Supply
Unit.
• Dismantle the stepper motor from the bracket by removing the four
#T20 Torx screws.
• If the printer has a liner takeup unit (see Chapter 8), remove the media
guide assy (see Chapter 7.5) to gain access to the belt running from the
stepper motor to the liner takeup unit.
• Remove the belts from the stepper motor pulleys. If no liner takeup unit
is fi tted, you can leave its timing belt in the recess in the center section.
• Loosen the 1.5 mm hexagonal grub screws that hold the pulleys of the
platen roller and liner drive roller and remove the pulleys and belts.
• Remove the stepper motor.
• Replace the rubber dampeners with a fresh set.
• Put back the stepper motor. If there is an optional liner takeup unit,
start by fi tting its belt to the motor's inner pulley. If no takeup unit is
fi tted, make sure that the pulley does not engage the belt. Then fi t the
belt and pulley to the liner drive roller and fi nally the belt and pulley to
the platen roller.
• Fit the four screws that hold the fl ange of the stepper motor.
• Connect the cable of the stepper motor to P10 on the Power Supply
Unit.
• Put back all remaining parts.
Intermec EasyCoder PF2i, PF4i, and PF4i Compact Industrial—Service Manual