TallyGenicom 6600 Series, Maintenance Manual

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Shuttle Drive Motor
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While the hammer is in flight the coils are de-energized and their magnetic
field collapses, restoring the magnetic attraction of the permanent magnet in
the hammer bank. After striking the ribbon and paper, the hammer rebounds
and is recaptured by the permanent magnet. When the shuttle reaches the
end of a sweep, it reverses direction, the paper is micro-stepped upwards one
dot row, and the hammer springs print the next row of dots as the shuttle
sweeps in the opposite direction. All this happens extremely rapidly: hammer
re-firing in a 2000 lpm printer, for example, takes about 419 microseconds,
with the vertical paper movement between dot rows occurring in 2.10
milliseconds.
Paper Transport System
Figure 58. Paper Transport System
A two-phase DC stepper paper feed motor, directed by the engine controller
(EC) on the controller board, drives two tractor sprockets by means of a
toothed belt linked to a pulley on the splined shaft. The stepper motor permits
extremely accurate vertical paper movement in 1/72 inch increments. This
drive configuration is designed for continuous, fan-folded paper from 3 to 17
inches wide and 1 to 6 sheets thick. To reverse paper movement (that is,
move it downward) a second motor opens and closes the platen by means of
a toothed belt linked to a pulley on the platen shaft. Opening the platen
183891a
Paper Supports
Shuttle Cover
Assembly
Tractor
Support
Shaft
Tractors
Paper Path
Splined
Shaft
Vertical
Adjustment
Knob and
Splined Shaft
Pulley
Paper Feed Timing
Belt (under the cover)