MX-6500N, MX-7500N (serv.man27). Section 13 Operational Descriptions - Sharp Copying Equipment Service Manual (repair manual). Page 10

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MX-7500N  OPERATIONAL DESCRIPTIONS  13 – 10
B. Operational descriptions
(1)
Outline
This section performs the following functions.
1)
Light is radiated to the document by the scanner lamp, and the
contrast of the reflected light is read by the CCD elements of
three lines of RGB to be converted into the image signal (ana-
log). 
2)
The image signals (analog) are converted into 10bit digital sig-
nals by the A/D converter.
3)
The image signals (digital) are sent to the image process sec-
tion (scanner control PWB).
(2)
Detail description
a. Optical section drive
The optical section drive power is transmitted from the scanner
motor (MIM) to the drive pulley and the wire through the belt, to
drive the copy lamp unit and the mirror base which are attached by
the drive wires.
The scanner motor (MIM) is controlled by the drive signal sent from
the scanner control PWB.
b. Scanner lamp drive
The scanner lamp (CLI) is driven by the scanner lamp drive voltage
generated in the CL LED Drive PWB according to the control signal
sent from the scanner control PWB.
c. Image scan/color separation
Light is radiated to the document by the scanner lamp, and the con-
trast of the reflected light is read by the CCD elements of three
lines of RGB to be converted into the image signal (analog).
The color components of document images are extracted to R, G,
and B separately by the three kinds of CCD elements (R,G,B).
The red CCD extracts the red component of document images, the
green CCD green the components, and the blue CCD the blue
components. This operation is called the color separation.
The CCD unit looks like one unit, but it includes three kinds of CCD
elements, R, G, and B. 
The document scan in the main scanning direction is performed by
the CCD element. The document scan in the sub scanning direc-
tion is performed by shifting the scanner unit with the scanner
motor. Document images are optically reduced by the lens and
reflected to the CCD.
The scan resolution is 600 dpi. 
(Image data for 1 line)
d. Image signal A/D conversion
1)
The image signal (analog) for each of R, G, and B is converted
into 10bit digital signal by the A/D converter.
Each color pixel has 10bit information. 
2)
The 10bit digital image signals of R, G, B are sent to the image
process section. 
e. Zooming operation
Zooming in the sub scanning direction is performed by changing
the scanning speed in the sub scanning direction.
Zooming in the main scanning direction is not performed optically,
but performed with the image process technology (by the software).
B
R
G
R
G
B
R
G
B
Red component 
image data
Green component 
image data
Blue component 
image data
CCD PWB
R
G
B
CCD
(6 Lines)
Analog IC
AFE ADC
LVDS
Buffer
Timing
Generator
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