Contact Image Sensor - Ricoh C226 Service Manual

ORIGINAL FEED SECTION

1.1.3 Contact Image Sensor

[A]
[B]
[F]
[E]
[D]
[C]
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
will remain stationary 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 reflected light from the
document into the image sensor.
Because of the short optical path inside the CIS, the focal depth is much
shorter than a CCD type scanner. Because of this, two springs at each end of
the CIS to push the unit against the exposure glass [F], so that the distance
from the original is identical all the time. However in book scanning mode, if
the original is out of the CIS's focal range, the scanned image may become
darker.
Because the analog output signal is a sawtooth waveform, data sampling
timing should be adjusted whenever a new CIS is installed in the machine.
C226 2-4 SM