Epson GT-1200, Руководство по обслуживанию

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GT-12000 Operating Principles
Rev. A
2-3
2.3 ELECTRICAL CIRCUIT OPERATIONS
This section describes the electrical circuit of the GT-12000.
2.3.1 Control Circuit Operation
The control circuits of this scanner are:
q
B054MAIN board (Main control circuit board)
q
B054SUB board (Relay board)
q
B054PNL board (Control panel board)
q
B054ISN board (CCD sensor board located on the CR)
Among various functions controlled by B054MAIN board, the core control
circuit of the scanner, and B054ISN, process from reading image with the
CCD sensor to processing image signals is described below:
q
B054ISN Board (CCD image sensor)
n
Photoelectric conversion:
Converts light reflected from the document (light energy) into
electrical energy (electrical charge).
n
Amplification
n
A/D conversion:
Converts the image data produced in the form of analog electrical
signal into 12-bit digital data.
q
B054 MAIN Board (processing image data)
ASIC (IC24) on this board manages most of the following functions:
n
Shading correction:
Performs image data correction on a black and white basis.
n
Numbers of image correction such as gamma correction, color
correction, halftoning correction. (They are carried out according to
the settings on the host side.)
After passed these processes, image data is finally output to the host.
C C D
C P U
I C 1 3
( H D 6 4 1 3 0 0 3 T F )
M P X A / D
I C 2
( A D 9 8 0 7 )
R
G
B
1 2 b i t
I C 2 4
( M E R C U R Y )
I C 2 8
( G G I F )
I C 1
E P R O M ( 1 M b i t )
I C 1 7
P S R A M ( 1 M b i t )
M o t o r d r i v e r
I C 3 / 4 / 5 / 6
D R A M ( 1 M x 4 )
I C 7 / 8 / 9
P S R A M ( 1 M b i t )
I C 1 8 - 2 3
D R A M ( 1 M x 4 )
I C 1 0 / 1 1 / 1 2
C N 2
B i - D I / F
C N 1 / 3
S C S I I / F
C N 6
O p t i o n
D o c u m e n t
I n v e r t e r
B 0 5 4 I S N B o a r d
< L i n e C o r r e c t i o n
M e m o r y >
< R G B I m a g e M e m o r y >
< B u f f e r M e m o r y >
T P U
A D F
< I / F C o n t r o l P r o c e s s o r >
< I m a g i n g P r o c e s s o r >
S h a d i n g
G a m m a C o r r e c t i o n
L i n e C o r r e c t i o n
M a i n / S u b A v e r a g e
C o l o r C o r r e c t i o n
S m o o t h i n g
Z o o m
B i / Q u a d F o r m a t t i n g
T E T
A A S
M i r r o r S h i f t
L e n s S h i f t
H P S e n s o r 1 / 2
B 0 5 4 M A I N B o a r d
Li
ght
Qu
an
tit
y
Mo
ni
tor
Figure 2-3. Control Circuit Block Chart