PCU (PHOTOCONDUCTOR UNIT) 31 March, 1999
2-18
2.2.11 BELT MARK DETECTION
There are 15 belt marks [A] on the right edge of the transfer belt. The transfer belt
home position sensor [B] (a reflective photosensor) on the front cover unit detects
these marks to align the laser exposure start position in the sub-scan direction for
the next image.
In 4C mode, when a page is completed and the transfer belt returns to the
write start position, the transfer belt moves forward one mark. Laser exposure in
the sub-scan direction for the next page starts there.
Because the PCU motor drives the transfer and OPC belts at the same time, this
prevents repeated exposure from the laser beam in the same position on the OPC
belt.
2.2.12 NEW PCU DETECTION
On a new PCU, the new PCU detection lever [A] at the bottom right is pointing
straight down.
When the PCU reset sensor in the main unit detects the new PCU detection lever,
the PCU counter resets. The main motor drives the new detection lever via a gear
[B] to release the sensor from the new PCU detection state.
G024D614.WMF
G024D615.WMF
[A]
[B]
[A]
[A]
[B]
