Ccd Pwb - Sharp AR-BC260 Service Manual

(4) Operational descriptions
a. Optical section drive
The optical section drive power is transmitted from the drive motor
(SM) through the belt, the drive pulley, and the wire to drive the
copy lamp unit and the mirror base which are attached by the drive
wires.
The drive motor (stepping motor) is controlled by the drive signal
sent from the MFP PWB.
b. Copy lamp drive
The copy lamp is driven by the copy lamp drive voltage generated
in the inverter PWB according to the control signal sent from the
MFP PWB.
c. Image scan/color separation
The CCD element, appeared as one unit, but has three separate
rows of CCD elements drive each for (RGB).
Light is radiated to a document by the copy lamp (Xenon lamp),
and the brightness of the reflected light is received by the three
line (RGB) CCD element and converted into (analog) image sig-
nals.
Each color component of RGB is separately extracted from the
document image by the three lines (RGB) of the CCD elements.
The red CCD extracts the red components from the document
image, the green CCD the green components, and the blue CCD
the blue components. This operation is called Color Separation.
The CCD element, appeared as one unit, but has three separate
rows of CCD elements drive each for (RGB).
Scanning of a document in the main scanning direction is per-
formed by the CCD elements. Scanning of a document in the sub
scanning direction is performed by shifting the scanner unit posi-
tion with the scanner motor.
Document images are optically reduced by the lens and projected
to the CCD elements.
The scanning resolution is 600dpi × 600dpi.
R
G
B
AR-BC260 DESCRIPTIONS OF EACH SECTION 7 - 24
(Image data for one line)
R
Red component of Green component of
image data image data
d. Image signal A/D conversion
1) Each image signal (analog) of RGB is converted into 8bit digi-
tal signal by the A/D converter. Each color pixel has 8bit infor-
mation (256 gradations).
2) Each 8bit digital image signal of RGB is sent to the image pro-
cess section.

CCD PWB

R analog IC
Color
3-line
G analog IC
CCD
B analog IC
CCD ASIC
R G
ICU PWB
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 by the image process technology (software).
G B
Blue component of
image data
R A/DC
G A/DC
B A/DC
R
G
B
B