UBI EasyCoder 601 XP – Service Manual Ed. 1
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Chapter 8 Print Unit
Description
The stepper motor drives the pressing roller via a short belt and the
ribbon return roller and the ribbon rewind unit via another, longer
belt. A freely rotating pulley attached to the printer's centre-line wall
makes the outside of the longer belt drive the ribbon return roller.
The stepper motor is driven in half-step mode between 70 and 145
mm/sec., and in full-step mode between 145 and 225 mm/sec.
However, when motor slows down at the end of a label, it will still
be driven in full-step mode even below 145 mm/sec., which will
result in a slightly increased noise level during the last centimetre
or so of the label.
The stepper motor has a stop accuracy of 2 dots, i.e. the theoretical
feed error will be max. +1 dot. However, mechanical conditions
such as a worn pressing roller or a slippery backing paper may affect
the feed accuracy adversely.
The stepper motor is fitted by means of two #T20 Torx screws to
a bracket, which in its turn is attached to the print unit gable by three
#T20 Torx screws. The pulleys of the stepper motor are glued to the
motor's shaft.
Replacement
Replace the stepper motor as follows:
• Turn off the power to the printer and disconnect the power cord.
• Open the front and right hand doors.
• Remove the cover over the electronics compartment, which is
held by eight #T10 Torx screws.
• Disconnect the cable to the stepper motor from P420 on the CPU
board.
• Remove the tension of the belt to the ribbon rewind unit by
loosening the two #T20 screws that holds the ribbon rewind unit.
• Dismantle the stepper motor from the bracket by removing the
two #T20 Torx screws.
• Free the belt from the pulley of the ribbon rewind unit and
manipulate the stepper motor so it comes free from both belts.
Remove the stepper motor.
• When putting back the stepper motor, fit the short belt first, while
letting the long belt hang loosely on the idler in a loop, through
which you can insert the pulley of the stepper motor. Do not put
the long belt around the pulley of the ribbon rewind unit until you
have fitted the stepper motor to the bracket and checked that both
belts are engaged by the stepper motor's pulleys.
• Connect the cable of the stepper motor to P420 on the CPU board
(marked “STM1”).
• Adjust the tension of the belts as described in chapter 8.5
and put
back the cover.
Refer to illustration on next page!
8.3 Stepper Motor
