Scanning; Contact Image Sensor - Ricoh MV310 Service Manual

DETAILED SECTION DESCRIPTIONS May 22nd, 1995
SCANNER

2.1.3. Scanning

1. Contact Image Sensor

[A]
[B]
[F]
[E]
[D]
[C]
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The contact image sensor (CIS) assembly [A] consists of an exposure glass
[B], a roof mirror lens array [C], a xenon lamp [D], and an image sensor [E].
The CIS moves under the exposure glass when scanning a book original, or
stays at the ADF scan line when scanning a sheet original using the ADF.
The image sensor is a row of 4096 photosensitive elements (B4 width x 16
dots/mm). The roof mirror lens array focuses the light reflected from the docu-
ment onto the image sensor.
Because of the short optical path inside the CIS, the focal depth is much
shorter than for a CCD type scanner. Because of this, two springs at each
end of the CIS push it against the exposure glass [F], so that the distance
from the original is kept the same all the time. However in book scanning
mode, if the original is out of the CIS's focal range, the scanned image may
get darker.
Because the analog output signal is a sawtooth waveform, data sampling tim-
ing should be adjusted whenever a new CIS is installed in the machine. Refer
to section 5.2.1 for more details.
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