Platen - Printronix T4204 Maintenance Manual

Chapter 4
Removal Procedures

Platen

To remove the platen, follow the steps below and refer to Figure 22.
1. Remove the top cover assembly (page 52).
2. Remove the ribbon drive belt (page 76).
3. Remove the platen drive belt (page 78).
4. Push the printhead release latch (1) to the rear to open the printhead
assembly.
5. Remove the grip rings (2) from both ends of the platen shaft. Remove the
platen shaft nylon washers (3) and the clutch (outer) pulley (4).
6. Using a 5/64 inch hex key, loosen the 42 tooth platen (inner) pulley (5).
Remove the pulley and the large nylon washer (6).
7. Slide the platen (7) toward the center panel until the short end of the
platen shaft (8) slides out of the flanged platen bearing (9). The center
panel flanged bearing (9) will be pushed out of its mounting hole.
8. Tilt the short end of the platen up and remove the platen from the printer.
To replace the platen:
1. Slide the platen sleeves (10) onto the platen shaft.
2. Insert the long end of the platen shaft through the center panel and the
short end of the platen shaft (8) through the support frame.
3. Install a flanged bearing (9) and nylon washer (3) on each side of the
platen shaft (8).
4. Align the platen edges with the guide plate (11) and install the grip ring (2)
on the short end of the platen shaft. Press the grip ring against the nylon
washer (3).
To replace the 42 tooth platen (inner) pulley:
1. Put a small dab of service-removable thread locking compound on the
pulley set screw.
2. Install the nylon washer (3) on the platen shaft.
3. Install the 42 tooth platen pulley (5) on the platen shaft with the flanged
side toward the center panel. Put a 0.005 inch shim between the pulley
and nylon washer to create a gap. Torque the pulley set screw to 11 inch-
pounds. Remove the shim.
To replace the clutch (outer) pulley:
1. Install the large nylon washer (6).
2. Install the clutch pulley (4) with the flanged side outward so the clutch will
rotate in the proper direction.
3. Put a 0.005 inch shim between the inner and outer pulleys to create a
gap. Install the nylon washer and grip ring. Remove the shim.
4. Install the platen drive belt (page 78).
5. Install the ribbon drive belt (page 76).
6. Install the top cover assembly.
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