Ricoh B286, Service Manual

Page: 545 / 622

Development
SM 6-37 B286/B289
Det
ails
6.6.6 ID SENSOR
The ID sensor [A] regularly reads two areas of the drum:
! Bare surface of the drum. The ID sensor measures the reflectivity of the bare drum,
converts this reading to a voltage, and stores this value (Vsg) in NVRAM.
! ID sensor pattern. The LPH writes an ID sensor pattern on the drum. The ID sensor
reads the density of this pattern, converts it to a voltage, and stores this value (Vsp) in
NVRAM.
The machine makes an ID sensor pattern to read Vsp after each copy.
But, the machine reads Vsg only one time. This is done during machine warm-up (see the
next section).