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FO-145A
CHAPTER 5. CIRCUIT DESCRIPTION
3.
Operational description
Operational descriptions are given below:
[1] Circuit description
1. General description
The compact design of the control PWB is obtained by using gate
arrays in the main controi section and high density printing of sudace
mounting parts. Each PWB is independent according to its function
as shown in Fig. 1.
2. PWB configuration
AC
cord
L!ne
cable
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p
y'
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r
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Powersupply PWB
f
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L
1
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TEL/LIU PWB
CCD PWB
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Control PWB
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1
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Panel PWB
,
Fig. 1
1) Control PWB
The control
PWB
controls peripheral PWBS, mechanical parts, trans-
mission, and performs overall control of the unit.
This machine employs a l-chip modem (R96SHF) which is installed
on the control PWB.
2) TEL/LIU
PWB
This PWB controls connection of the telephone line to the unit.
3) Power supply PWB
This PWB provides voltages of +5V, +12V, and +24V to the another
PWB.
4) Panel PWB
The panel PWB allows input of the operation keys.
Transmission operation
When a document is loaded in standby mode, the state of the
document sensor is sensed via the main controller gate array. If
the sensor signal was on, the motor is started to bring the docu-
ment into the standby position. With depression of the START key
in the off-hook state, transmission takes place.
Then, the procedure is sent out from the modem and the motor is
rotated to move the document down to the scan line. In the scan
processor, the signal scanned by the CCD is sent to the internal
image processor and the AD converter to convefi the analog sig-
nal into binary data. This binary data is transferred from the scan
processor to the image buffer within the RAM and encoded and
stored in the transmit buffer of the
RAM.
The data is then con-
verted from parallel to serial form by the modem where the serial
data is modulated and sent onto the line.
Receive operation
There are two ways of starting reception, manual and automatic.
Depression of the START key in the off-hook mode in the case of
manual receive mode, or Cl signal detection by the LIU in the
automatic receive mode.
First, the CPU controls the procedure signals from the modem to
be ready to receive data. When the program goes into phase C,
the serial data from the modem is converted to parallel form in the
modem interface of the main control gate array which is stored in
the receive buffer of the RAM. The data in the receive buffer is
decoded software-wise to reproduce it as binary image data in the
image buffer. The data is DMA transferred to the recording
proces-
sor within the main
control
gate array
which is then converted from
parallel to serial form to be sent to the thermal head. The data is
printed line by line by the CPU which is assigned to control the
motor rotation and strobe signal.
Copy operation
To make a copy on this facsimile, the COPY key is pressed when
the machine is in stand-by with a document on the document table
and the telephone set is in the on-hook state.
First, depression of the COPY key advances the document to the
scan line. Similar to the transmitting operation, the image signal
from the CCD is converted to a binary signal in the DMA
mode
via
the main
control
gate
array
which is then sent to the image buffer
of the RAM. Next, the data is transferred to the recording proces-
sor in the DMA mode to send the image data to the thermal head
which is printed line by line. The copying takes place as the opera-
tion is repeated.
5) CCD PWB
This PWB controls the pickup optical device,
6)
LCD
PWB
This PWB controls the LCD display.
5–1
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