Appendix D. Mechanical Description - Ricoh FAX220 Service Manual

APPENDIX D. MECHANICAL DESCRIPTION

1. ADF/Scanner
The machine has two significantly different points in the ADF/scanner mechanism from older models. The first point
is the integrated scanner and sensor mechanism, and the second point is the simplified ADF mechanism.
1-1. Integrated Scanner/Sensor Mechanism
The document sensor (SB-
1) and scan line sensor (SB-
2) are integrated into the
scanner mechanism. The ba-
sic composition of these sen-
sors is similar to
photointerrupters. However,
instead of using discrete
photodiode/phototransistor
assemblies for each sensor,
elements of the LED array
and CCD are used.
On the left hand side of the
LED array, there are red
LEDs dedicated for the two
scanner sensors. These
LEDs are always on. Light
from these LEDs passes
through the lens to the right
hand side of the CCD,
where there are 112 ele-
ments specially provided to detect this light (the 4th bit is allocated to the scan line sensor (SB-2) and the 58th bit is
allocated to the document sensor (SB-1)).
If a sensor actuator blocks the light path, the CCD waveform shows a dropout, then the CPU will detect it.
In standby mode, the CCD output is as shown on the
right. The peak on the left side of the waveform indi-
cates that the light path in both of the sensors is un-
blocked.
When a document is placed in the feeder, the docu-
ment sensor actuator blocks the light path to the
CCD. When the cpu detects this, it starts prefeeding
the document and switches on the rest of the LED ar-
ray.
SB-1 (Document Sensor)
Actuator
SB-2 (Scan Line
Sensor) Actuator
+5V
White Reflector
SBU
CCD
Lens
LED Array
D-1
1728 elements
for
Image
58th bit for document sensor
4th bit for scan line sensor
112 elements
for
SB-1,2
+24V