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4.6.36 Ribbon Shields (285 Ipm)
Lower Shield
Removal
1.
2.
3.
4.
Remove the printer covers.
Remove the print unit (4.6.10).
Remove six screws
m
from the front of the
platen.
Remove the ribbon shield.
Replacement
1.
2.
3.
4.
Install the ribbon shield using the six screws
m
(do not tighten).
Hold the ribbon shield up against the platen
as shown
Ill,
then tighten the screws.
Replace the print unit (4.6.10).
Replace the ribbon (4.6.28) .
5.
Replace the covers.
Upper Shield
Removal
1.
2.
3.
The screws are located under the print
position scale near print positions 4 and
129. Break the scale at these points to
expose the screws
II.
Remove the mounting screws from the pivot
brackets
m.
Remove the upper ribbon shield
II
and the
pivot brackets.
Replacement
1.
Place the pivot brackets
m
on the shield
assembly
[I .
2.
Locate the shield and pivots on the platen.
3.
Start the screws in the pivot brackets, but
do not tighten.
Do the upper ribbon shield adjustment.
Service Check
1.
Set forms thickness control on 1.
2.
3.
Open the print unit, then slowly lift it until
the upper ribbon shield comes near the
hammer plates. At this point, ensure that
the upper ribbon shield is parallel to the
hammer plates
m .
Open the upper ribbon shield and verify
that there are no damaged edges on the
shield
II.
4-132
Adjustment
1.
2.
3.
4.
Remove the paper, ribbon, and type belt.
Close the print unit and set the forms
thickness control to 6.
Loosen the upper ribbon shield
mounting screws
II .
Push the upper shield toward the paper
path until the lip of the shield
II
just
contacts, and is parallel with, the hammer
plate at
m .
Tighten the mounting screws.
5.
Load approximately 22 inches (550 mm)
of one-part forms that are wide enough to
cover the print line.
6.
7.
8.
Close the print unit and set the forms thick-
ness control to 1.
Measure the tension while pulling the forms
upward
m .
The tension should not be
more than 250 grams. If the tension is
correct, go to step 7.
If the tension measured in step 5 is more
than 250 grams:
a. Open the upper ribbon shield, then
measure the tension
m
again. The
tension should not be more than 250
grams. If correct, go to step 6d.
b. If not correct, the extra tension is from
the forms path below the upper ribbon
shield. Inspect the forms tension assem-
bly (4.6.45), lower ribbon shield, and
lower forms path.
c. Close the upper ribbon shield. Measure
the tension again (same as step 5). If
correct, go to step 7.
d. Close the upper ribbon shield. Loosen
the mounting screws, then move the
upper ribbon shield 0.005 inch (0.13
mm) toward the front of the machine.
Measure the tension again. If not
correct, repeat step 6c, but make the
gaps
II
0.005 inch (0.13 mm) smaller
each time until the tension is correct.
e. Tighten the mounting screws in the
pivot brackets.
9.
Replace the type belt and the ribbon.
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