Ricoh LDD250, Руководство по обслуживанию

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DRUM
C262/C265 6-74 SM
6.7.6 MASTER DETECTION
The 1st drum master sensor [A] detects a master on the drum.
If a master is on the drum, the black patch [B] is covered and the sensor detects
the light reflected from the master. Printing starts when the start key is pressed. If
an original has been set, the old master is ejected from the drum before making a
new master.
If no master is on the drum, the black patch is exposed. The black patch does not
reflect light back to the sensor. The machine will skip the master eject process and
immediately begin making a new master.
A similar sensor, the 2nd drum master sensor [C], is located just above the 1st
drum master sensor. This sensor determines if the master making process
correctly wrapped the master around the drum.
The drum starts turning soon after the drum master clamper clamps the leading
edge of the master. The 2nd drum master sensor checks for the presence of the
master (master clamping error check). If a master is not detected, a clamping error
occurred. The master feed stops, the drum returns to the home position, and the
machine displays a master feed jam message.
The 1st drum master sensor cannot check for master clamping errors, because the
black patch has moved.
Both sensors use the same black patch [B] to detect the master.
NOTE: In this model, the black patch on the drum is larger.
The patch ensures that the master pick-up roller in the master eject roller
unit contacts the drum surface evenly at this part of the drum, resulting in
even pressure from the roller all across the drum.
C262D067.WMF
[A]
[B]
[C]