Ricoh FT9101 - Page 327

2.3.2 Photoconductor
The photoconductor uses a highly sensitive laminated
OPC consisting of two photoconductive layers,
constructed in the form of a belt. The layers consist of a
thin alloy conductive layer and a transparent base.
The OPC belt has conductive portions at both edges.
They are grounded with grounding brushes mounted on
the main body of the machine.
The OPC belt has a peripheral length of 1,280 mm, and
its image producing area is equally divided into 5 A4/B5
segments, 4 B4 segments, or 3 A3 segments.
To avoid forming the image on the seam of the belt and
to detect the segment area (image production area), an
OPC home position mark of (6 mm
2
), that can be
detected by the OPC sensor, is on one edge of the OPC
belt. If this mark cannot be detected, this causes Error
reset #51.
Copy paper A3 DLT B4 LG LT A4 B5
No. of
segments
3 4 5
Segment
intervals (mm)
426.7 320 256
CPM 61 81 101
CAUTIONS
• Never expose the OPC to outside light.
The OPC is especially sensitive to short
wavelength light, such as blue and violet.
• If exposed to direct sunlight, this will cause
partial changes in the ability of the OPC to
function properly. Differences will occur in
the quality between segments, and the OPC
should be left in a dark room for several
days in order to recover from exposure to
light.
• Although the OPC belt is scarcely affected
by exposing it to ordinary indoor light
(1,000 lux or less) for several minutes, be
sure to cover the OPC belt when it is
removed from the machine.
• Signs of optical fatigue in the OPC belt
caused by exposure to light include:
insufficient charge, large residual potential,
reduction in the density of the image, and
dirty background.
• Never clean the OPC belt with organic base
chemicals such as alcohol. Use only a dry
rag to clean the OPC belt.
• Never fold the OPC belt. Folds will show on
copies. Handle the OPC belt carefully
when you are mounting it.
Image production area in A4 copies
Cross-section of the OPC Belt
Home
position
mark
Transparent base
Grounding brush
Seam
Grounding brush
1 July 1994
OPC Unit
2-27