Sharp FO 4400 - B/W Laser - All-in-One Service Manual page 104

FO-4400U
FO-CS1
(4) Scanner control block
1) Image signal process block
The CIS is driven by MAIN ASIC (IC6), and the output video signal from
the CIS is input into IC6 through the amplifying circuit.
The ADC and buffer are provided in IC6, and the digital image process-
ing is performed.
2) Mechanical control block
The mechanical control block is mainly composed of MAIN ASIC to con-
trol the following.
(a) Scanner motor control
The revolution speed and timing of the scanner motor are controlled to
output the control signals to the motor driver (IC3).
(b) Verification stamp and LED lamp control
On/off of the end verification and LED lamp of CIS is controlled with
the software.
AMPLIFIER
CIS
VIDEO
CIRCUIT
SIGNAL
VCC 28
–
PHASE1
25
+
VREF1 26
–
ENABLE1 24
+
–
22
I01
+
–
23
I11
+
I I
0 1
L L Vref/ (10 x R
H L Vref/ (15 x R
L H Vref/ (30 x R
H H
Note: When ENABLE = H or I
0
MAIN ASIC
CLOCK
Fig. 5
14
6 7 1
OUTPUT
BLOCK
TSD
OUTPUT
BLOCK
–
+
3 2
Output Current
) = I
E OUT
) = I x 2/3
E OUT
) = I x 1/3
E OUT
0
= I = H, the output is in OFF state.
1
(5) Speaker amplifier
The speaker amplifier monitors the line under the on-hook mode, out-
puts the buzzer sound generated by SUB ASIC, ringer sound, DTMF
generated from the modem, and line sound.
(6) Page memory block
W986416DH or MT48LC4M16A2TG (IC5): pin-54, TSOP
(64 Mbit SDRAM)
The page memory block is composed of one SDRAM of 64 Mbits, being
commonly used as the image memory. The memory is divided into the
page memory for the scanner and the page memory for printing.
This memory is controlled by the MAIN ASIC directly.
The page memory for scanner is composed of the partial area of IC5.
The image data of approx. one page (except in the super fine mode) of
the draft read with the scanner can be stored. They are stored until they
are contracted by CODEC function in MAIN ASIC.
The page memory for printing is composed of the remaining areas of
IC5 and can store approx. one page of the image data decoded by
CODEC function in MAIN ASIC. The data are stored until they are trans-
ferred to Printer PWB with the SUB ASIC and printed.
(IC6)
(7) Driver block
Sending motor driver (IC3: LB1845) ---- 28-pin DIP
This IC driver at the sending motor at the constant current with the bipo-
lar, chopper system.
8
OUTPUT OUTPUT
BLOCK BLOCK
OUTPUT OUTPUT
BLOCK BLOCK
ONE ONE
SHOT SHOT
27 4 11 15 16 12
Fig. 6
[Truth Table]
ENABLE
L
L
H
5 – 14
9
OUTPUT
BLOCK
OUTPUT
BLOCK
–
+
13
PHASE OUTA OUTB
H H L
L L H
– OFF OFF
–
18 PHASE2
+
17 VREF2
– ENABLE2
19
+
–
21 I02
+
–
20 I12
+