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DETAILED SECTION DESCRIPTIONS
SCANNER
2.1.2. Image Scanning
The scanner consists of a shading plate [A] and a contact image sensor
(CIS) assembly [B]. Inside the CIS are an exposure glass [C], a rod lens ar-
ray [D], an image sensor [E], and an LED array [F].
The image sensor consists of a row of 1728 photosensitive elements. Light
from the LED array is reflected from the document and focused onto the im-
age sensor by the rod lens array. Because of the short optical path inside the
CIS, the focal depth is much shorter than for a CCD type scanner. Because
of this, the shading plate pushes the document so that the document surface
always touches the exposure glass at the scan line.
The image sensor assembly is not adjusted at the factory, so it does not need
any adjustment at replacement in the field.
The image sensor scans the original one line at a time, and outputs an ana-
log signal for each line. The voltage from each element depends on the
intensity of the light reflected from the original onto the element.
The machine feeds the document through the scanner using one of the fol-
lowing step widths: the scanned lines are transmitted without any OR
processing.
3.85 lines/mm in Standard resolution
7.7 lines/mm in Detail resolution
15.4 lines/mm in Fine resolution
[C]
[D]
[A]
[E]
2-2
November 28th, 1995
[F]
[B]
H505D522.wmf
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