TM 5-6675-324-14
(1) Cassette feed. Cassette paper feed solenoid SL2 is activated, releasing
the ratchet wheel on the cassette paper feed roller shaft. The feed rollers rotate
exactly one-half turn and then stop. The paper feed rollers are flat on one side,
and they stop in contact with the paper and hold it in place. SL2 acts to hold the
rollers in position. This is called prefeed. At the end of the INTR, the reverse
clutch is switched on and the copyboard moves backward to the start position. The
CBSP signal is generated to switch the reverse clutch off and the forward clutch on.
The halogen lamp output rises to high intensity and the blank shutter closes. When
the copyboard begins to move forward, the image exposure begins. When the copyboard
magnet approaches reed switch RS3, the PFP signal is generated and SL2 is switched
off. This allows the cassette paper feed rollers to rotate farther and feeds the
paper sheet up to the registration rollers. As these are not rotating, the paper
bellies up. This helps to prevent skew feed. At the end of the scanning movement,
the forward clutch disengages and the reverse clutch engages. The distance moved
before stopping and returning to the home position depends on the type of paper
cassette installed.
(2) Manual paper feed. When a sheet of copy paper is inserted in the manual
paper feed guide, a photocell generates PDP1 signal. After 1.5 see, prefeed begins.
feed roller shaft. This permits the rollers to begin rotating, pushing the paper
partway into the copier. Another sensor then emits PDP2 signal. SL1 is deactivated
35 pulses after PDP2, and the pawl release engages the ratchet wheel, stopping the
rotation of the manual feed rollers. This brings the paper to the same point
reached during prefeed when using cassette feed. All timing beyond this point is
identical to cassette feed, except that SL1 is actuated to release the manual paper
feed rollers, which rotate again to feed the copy paper to the registration rollers
when the PFP signal is generated.
When the copy paper trailing edge passes the sensor of the PDP2, the manual feed
solenoid SL1 again is deactivated and its pawl stops the rotation of the manual
paper feed rollers. The manual feed system discriminates between large and small
sizes of paper by sensing the time it takes to pass the sensor PDP3. If paper is
still present 105 clock pulses after generation of the RGP signal during CBFW
movement, it is a large sheet. If no paper is present, it is small.
The position of the copyboard is monitored by reed switches that send signals to the
microcomputer when a magnet on the copyboard passes. The process is repeated for
every copy. If multiple copies are being made, the copyboard does not stop at the
home position after completing a scan, but returns fully to the start position.
After completing a scan, light intensity is reduced during the reverse movement.
The lamp will switch to high intensity in preparation for the next copying operation
33 pulses after the copyboard passes the home position and sends CBHP signal. When
the copyboard finishes its last forward movement and begins to reverse in prepara-
tion for stopping at its home position, 8 pulses are added to the time during which
the drum rotates. This gives time for the copy counter to rotate.
At the end of 8 pulses, the copier enters the last rotation period to give the drum
two turns and to discharge copy paper. During the LSTR (361 pulses), three impor-
tant steps are accomplished: The latent image on the drum is transferred to copy
paper; preconditioning, primary, and transfer coronas are switched off; and the
secondary corona is switched to low output. This prevents the drum surface electric
potential from becoming too negative and ensures a uniform distribution of charge on
the surface.
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