Contact Image Sensor - Ricoh C231 Service Manual

SCANNER AND OPTICS

2.1.3 CONTACT IMAGE SENSOR

[A]
[D]
The contact image sensor (CIS) assembly [A] consists of the exposure glass [B],
roof mirror lens array [C], xenon lamp [D], and the image sensor [E].
The CIS moves under the exposure glass when scanning a book original, and
remains 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 light reflected from the document
onto the image sensor.
Due to the short optical path of a CIS unit, the focal depth is much shorter than in a
CCD type scanner. Because of this, two springs are used to push the CIS against
the exposure glass [F], to keep the distance between the CIS and the original
constant. In book scanning mode, if the original is out of the CIS focal range,
however, the scanned image may be darkened.
NOTE: Due to the characteristics of the CIS, shadows of a paste-up original tend
to appear on copies. To counter this, press the paste shadow erase key on
the operation panel to use the paste shadow erase mode.
The strength of the paste shadow erase level can be changed with SP no.
28.
C231/C237/C238
[B]
[C]
2-4
[F]
[E]
C231D503.WMF
SM