Panasonic KX-FC253UA-T / KX-FC258RU-T Service Manual ▷ View online
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KX-FC253UA-T/KX-FC258RU-T
6.4.
Facsimile Section
6.4.1.
Image Data Flow During Facsimile Operation
Copy (Fine, Super-Fine, Half Tone)
1. Line information is read by CIS (to be used as the reference white level) via route1, and is input to IC10. Refer to Block Dia-
gram (P.22)
2. In IC10, the data is adjusted to a suitable level for A/D conversion in the Analogue Signal Processing Section, and via route2
it is input to A/D conversion (8 bit). After finishing A/D conversion, the data is input to the Image Processing Section via
route3. Then via route4 and route5, it is stored in RAM as shading data.
route3. Then via route4 and route5, it is stored in RAM as shading data.
3. The draft’s information that is read by CIS is input to IC10 via route1. After it is adjusted to a suitable level for A/D conversion
via route2, the draft’s information is converted to A/D (8 bit), and it is input to the Image Processing Section. The other side,
the shading data which flows from RAM via route6 and route7, is input to the Image Processing Section. After finishing the
draft’s information image processing, white is regarded as "0" and black is regarded as "1". Then via routes4 and 5, they are
stored in RAM.
the shading data which flows from RAM via route6 and route7, is input to the Image Processing Section. After finishing the
draft’s information image processing, white is regarded as "0" and black is regarded as "1". Then via routes4 and 5, they are
stored in RAM.
4. The white/black data stored as above via routes6 and8 is input to the P/S converter. The white/black data converted to serial
data in the P/S converter is input to the Thermal Head via route9 and is printed out on recording paper.
Note:
Note:
Standard: Reads 3.85 lines/mm
Fine/Photo: Reads 7.7 lines/mm
Super-Fine: Reads 15.4 lines/mm
Fine/Photo: Reads 7.7 lines/mm
Super-Fine: Reads 15.4 lines/mm
Transmission
1. Same processing as Copy items 1 - 3.
2. The data stored in the RAM of IC10 is output from IC10 via routes6 and 10, and is stored in the system bus.
2. The data stored in the RAM of IC10 is output from IC10 via routes6 and 10, and is stored in the system bus.
Via route11, it is stored in the communication buffer inside DRAM (IC17).
3. While retrieving data stored in the communication buffer synchronous with the modem, the CPU (inside IC10) inputs the data
to the modem along route12, where it is converted to serial analogue data and forwarded over the telephone lines via the
NCU Section.
NCU Section.
Reception
1. The serial analogue image data is received over the telephone lines and input to the modem via the NCU section, where it is
demodulated to parallel digital data. Then the CPU (IC10) stores the data in the communication buffer DRAM (IC17) along
route12.
route12.
2. The data stored in DRAM (IC17) is decoded by the CPU (IC10) via route12, and is stored in DRAM (IC17) via routes13 and 5.
3. Same processing as Copy item 4.
3. Same processing as Copy item 4.
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KX-FC253UA-T/KX-FC258RU-T
6.4.2.
Block Diagram
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KX-FC253UA-T/KX-FC258RU-T
6.4.3.
Thermal Head
1. Function
This unit utilizes the state of the art thermal printer technology.
The ink film is chemically processed. The ink film is comprised of two parts: an ink layer and a base film. When the thermal
head contacts this ink film, it emits heat momentarily, and the ink layer is melted and transferred to the paper. If this continues,
letters and/or diagrams appear, and the original document is reproduced.
The ink film is chemically processed. The ink film is comprised of two parts: an ink layer and a base film. When the thermal
head contacts this ink film, it emits heat momentarily, and the ink layer is melted and transferred to the paper. If this continues,
letters and/or diagrams appear, and the original document is reproduced.
2. Circuit Operation
Refer to the block diagram and the timing chart on the following page.
There are 9 driver ICs aligned horizontally on the thermal head and each one of these ICs can drive 192 heat-emitting regis-
ters. This means that one line is at a density of 192
There are 9 driver ICs aligned horizontally on the thermal head and each one of these ICs can drive 192 heat-emitting regis-
ters. This means that one line is at a density of 192
×9=1728 dots=(8 dots/mm).
White/Black (white=0, black=1) data in one line increment is synchronized at IC10 pin 117 (THCLK), and sent from IC10 pin
116 (THDAT) to the shift register of the ICs. The shift registers of the 9 ICs are connected in series, and upon the shift of the
1728 dot increment, the shift register becomes filled with data, and a latch pulse is emitted to each IC from IC10 pin 118
(THLAT).
With this latch pulse, all the contents of the shift registers are latched to the latch registers. Thereafter, through the addition of
strobes from the IC10 pins (103, 104), only the dot location of black (=1) among latched data activates the driver, and the cur-
rent passes to heat the emitting body to cause heat emission.
Here, the two line strobes, STB1 and STB2, impress at intervals of 9.216 msec, as required for one-line printout.
The sequence is shown on the next page. [Moreover, for the strobe width, the thermistor value inside the thermal head is
detected according to IC10 pin 4. Depending on that value, the strobe width is recorded in FLASH ROM (IC16). Accordingly,
the strobe width is determined.]
When the thermal head is not used, the IC10 (17, THON) becomes low, Q603 turns OFF, Q401 turns OFF, and the +24V
power supply for the thermal head driver is not impressed to protect the IC.
116 (THDAT) to the shift register of the ICs. The shift registers of the 9 ICs are connected in series, and upon the shift of the
1728 dot increment, the shift register becomes filled with data, and a latch pulse is emitted to each IC from IC10 pin 118
(THLAT).
With this latch pulse, all the contents of the shift registers are latched to the latch registers. Thereafter, through the addition of
strobes from the IC10 pins (103, 104), only the dot location of black (=1) among latched data activates the driver, and the cur-
rent passes to heat the emitting body to cause heat emission.
Here, the two line strobes, STB1 and STB2, impress at intervals of 9.216 msec, as required for one-line printout.
The sequence is shown on the next page. [Moreover, for the strobe width, the thermistor value inside the thermal head is
detected according to IC10 pin 4. Depending on that value, the strobe width is recorded in FLASH ROM (IC16). Accordingly,
the strobe width is determined.]
When the thermal head is not used, the IC10 (17, THON) becomes low, Q603 turns OFF, Q401 turns OFF, and the +24V
power supply for the thermal head driver is not impressed to protect the IC.
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KX-FC253UA-T/KX-FC258RU-T
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