Tektronix Phaser 840, Service Manual

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106 Phaser 840 and 850 Color Printers
Cap/wipe/purge assembly belt adjustments
The tension of the cap/wipe/purge assembly belts is factory-set. Do not adjust
the belts’ tension unless you remove or replace one or both belts. The belts are
Kevlar-reinforced; they will not stretch over their lifetime. The belts are also
factory-adjusted for parallel tracking (alignment). As long as the belts, cap/
wipe/purge assembly motor, or the belt clips (which hold the cap/wipe/purge
assembly) are not disturbed, no adjustment is needed.
However, if you replace one or both of the belts or the cap/wipe/purge drive
motor, you must ensure that the belts are in alignment (timing) with each other;
this ensures that the cap/wipe/purge assembly is perfectly aligned to the
faceplate of the printhead. If the belts are not aligned, the printhead purging is
ineffective, due to poor sealing between the printhead faceplate and the cap/
wipe/purge assembly.
1. Ensure that the cap/wipe/purge assembly is properly installed.
2. Tilt the printhead back to its locked position.
3.
Rotate the large drive gear to pull the cap/wipe/purge assembly to
about the middle of its travel in the chassis frame slot.
4. Ensure each timing belt lock is tightened to its fourth tooth, as
illustrated.
5. Position the right-side timing belt lock so its pointer points at the index
mark on the printer frame.
6. Holding the right belt so it does not move, inspect the left-side timing
belt lock’s pointer; it should point between the index marks on the left-
side printer frame.
If the left-side pointer does not point between the index marks while
the right-side belt lock is at its mark, loosen the right timing belt by
removing the lower idler pulley and adjust the belt so that it aligns with
the timing mark.
7. Repeat until the right-side timing lock’s pointer points at the index
mark on the right-side frame as the left-side timing belt lock’s pointer
points between its index marks on the left-side frame.