TM 5-6675-325-14
(b) Outside cam S11.
With the mirror away from the “home” position, this
switch is held open, producing a high signal at TP9.
(c) Inside cam S1O.
With the mirror away from the ‘home” position, this
switch is closed, producing a low signal at TP7. The logic board now has a high
signal at TP5 and TP9 with a low signal at TP7.
These are indications required to
initiate a paper drive cycle.
The paper drive logic now applies a start signal from
integrated circuit U21O to transistor V3.
This fires triac V1, which energizes paper
drive motor M2.
As main viewing mirror approaches the mirror’s forward position, the
paper is driven down the printing easel to the expose position. As either optical
sensor 0S1 or 0S2, depending on position of print length switch, detects leading edge
of paper, it puts TP5 low.
With TP5 low, the paper drive logic turns off paper drive
triac V1 and stops the paper drive motor.
(8) The main viewing mirror stops at the mirror’s forward position. Contacts
of mirror forward switch S11 close, putting TP9 low. This turns off mirror motor
triac V2, which stops mirror motor M3.
The contacts of exposure lamp switch S9
close and apply voltage to exposure lamp.
The main viewing mirror remains in the
forward position, and exposure lamp exposes paper on the printing easel.
(9) The exposure control VR1 setting adjusts the timing circuit composed of
V5 and U25 on the logic board.
The timing circuit determines the period of time
that the main viewing mirror assembly remains in the forward position and therefore,
how long exposure lamp switch S9 remains closed.
At the end of the exposure cycle,
the timing circuit overrides low on TP9 and starts mirror motor M3.
(10) The main viewing mirror moves away from the forward position back toward
the “home” position.
Contacts of exposure lamp switch S9 open, and exposure lamp
goes out.
As the main viewing mirror approaches the “home” position, linkage of the
mirror actuates the paper cutter, the upper nip rollers contact the paper, and the
drive rollers drive the paper down the printing easel. When the paper is moved down
the printing easel, it clears optical sensors 0S1 and 0S2, and TP5 goes high. With
the main viewing mirror in the “home” position, mirror home switch S1O opens and TP7
goes high.
Mirror forward switch S11 opens and TP9 goes high. Exposure lamp
switch S9 closes and exposure lamp comes on.
The reader-printer is now ready to
begin another print cycle.
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