Ricoh FT6645 Manual page 40

23 April 1993
1.4.2 Image Density Sensor Detection
[B]
Drum
[A]
V and V are checked by the ID sensor [A]. The ID sensor is located
SG SP
underneath the drum cleaning section.
There is no ID sensor pattern in the optics, however, a pattern image is made
on the OPC drum by the charge corona unit [B] and the erase lamp [C].
V is the ID sensor output when checking the erased drum surface.
SG
V is the ID sensor output when checking the ID sensor pattern image.
SP
To compensate for any variation in light intensity from the sensor LED, the
reflectivity of both the erased drum surface and the pattern on the drum are
checked.
V Detection
SP
1 2
1st Series of Copies
(8 copies)
V
SG
Detection
V is detected every time the machine starts copying.
SG
During V detection, the development sleeve rollers do not rotate and no
SG
development bias is applied.
V is detected after copying is completed if 10 or more copies have been
SP
made since V was last detected. Since the transfer belt must be released
SP
when checking V
SP
[C]
bias
3 4 5 6 7 8
, a V check cannot be done during continuous copying.
SP
LED
ON
V
SG
V Detection
SP
9 10 11 12 13
2nd Series
of Copies
V
SG (5 copies)
Detection
2-15
PROCESS CONTROL
LED
ON
4 V
V
SP
V Detection
SP
14 15 29 30
3rd Series of
Copies (17
V
SG copies)
Detection
31
V
SG
Detection