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3.2 Scanner section
3.2.1 How to scan documents
The scanner has sensors that are arranged in a line.
These sensors scan a certain area of a document at a time
and deliver outputs sequentially. When the line is finished, the
next line is scanned, and this procedure is repeated.
The figure on the side shows the case where the latter
two sections of an image which are scanned are shown
with solid lines and the former two sections which are being
transmitted are shown with dotted lines.
The direction of this line is called "main scanning direc-
tion," and the scanning direction "sub scanning direction."
With reference to the figure, one line is divided into 4
sections. Actually, however, one line is divided into thou-
sands of sections. For scanning, the light receiving element
called CCD is used.
The basic resolution indicates the scanner capacity. The
basic resolution is expressed in dpi (dot/inch) which shows
the number of light emitting elements per inch on the docu-
ment.
The basic resolution of this machine is 400dpi.
In the sub scanning direction, at the same time, the motor
that drives the optical system is controlled to scan the image
at the basic resolution.
3.2.2 Basic structure of scanner section
1
Copy lamp (Xenon lamp)
4
No. 2 mirror
7
No. 2/3 mirror unit
10
Mirror motor
The scanner unit performs scanning in the digital optical system. The light from the light source (Xenon lamp) is reflected by
a document and passed through three mirrors and reduction lenses to the CCD element (image sensor) where images are
formed. This system is known as the reduction image sensor system. Photo energy on the CCD element is converted into
electrical signals (analog signals). (Photo-electric conversion). The output signals (analog signals) are converted into digital
signals (A/D conversion) and passed to the MCU (main control/image process section). The resolution at that time is 400dpi.
The mirror unit in the scanner section is driven by the mirror motor. The MHPS is provided to detect the home position of the copy
lamp unit.
3-2
2
Reflector (light conversion plate)
5
No. 3 mirror
8
Copy lamp unit
11
MHPS (Mirror home position sensor)
Service Manual
3
No. 1 mirror
6
Lens
9
CCD
Y101700-5
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