5.4.3. THERMAL HEAD
1. Function
This unit utilizes state of the art thermal printer technology.
The recording paper (roll paper) is chemically processed. When the thermal head contacts this paper it emits heat momentarily,
and black dots (appearing like points) are printed on the paper. If this continues, letters and/or diagrams appear, and the original
document is reproduced.
2. Circuit Operation
There are 9 driver ICs aligned horizontally on the thermal head and each one of these ICs can drive 192 heat emitting registers.
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 increments is synchronized at IC1 pin 166 (THCLK), and sent from IC1 pin 163
(THDAT) to the shift register of the ICs. The shift registers of the 9 ICs are connected in series, and upon the shift of dot
increment 1728, all the shift registers become filled with data, and a latch pulse is emitted to each IC from IC1 pin 167 (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 IC1 pins (159, 160) only black dot locations (=1) among latched data activates the driver, and the current
passes to heat the emitting body causing heat emission.
Here, the three line strobes, STB1 to 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 IC1 pin 207. (See BLOCK DIAGRAM (P.109).) Depending on that value, the strobe width is recorded in
ROM (IC2).
Accordingly, the strobe width is determined.
When the thermal head is not used, the IC1 (170, THON) becomes low, Q8 turns OFF, Q13 turns OFF, and the +24 V power
supply for the thermal head driver is not impressed to protect the IC.
110
KX-FT72BR-G
Summary of Contents for KX-FT72BR-G
Page 3: ...1 1 LCD MESSAGE 1 INTRODUCTION 3 KX FT72BR G ...
Page 8: ...1 11 TEST CHART 1 11 1 ITU T NO 1 TEST CHART 8 KX FT72BR G ...
Page 9: ...1 11 2 CCITT NO 2 TEST CHART 9 KX FT72BR G ...
Page 10: ...1 12 LOCATION OF CONTROLS 1 12 1 OVERVIEW 10 KX FT72BR G ...
Page 29: ...2 3 4 3 MULTIPLE FEED CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 29 KX FT72BR G ...
Page 30: ...2 3 4 4 SKEW CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 30 KX FT72BR G ...
Page 34: ...CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 34 KX FT72BR G ...
Page 39: ...2 3 5 1 4 THE UNIT CAN COPY BUT CANNOT TRANSMIT RECEIVE 39 KX FT72BR G ...
Page 45: ...45 KX FT72BR G ...
Page 46: ...CROSS REFERENCE TEST FUNCTIONS P 82 46 KX FT72BR G ...
Page 47: ...CROSS REFERENCE TEST FUNCTIONS P 82 47 KX FT72BR G ...
Page 48: ...48 KX FT72BR G ...
Page 49: ...CROSS REFERENCE TEST FUNCTIONS P 82 CROSS REFERENCE TEST FUNCTIONS P 82 49 KX FT72BR G ...
Page 50: ...50 KX FT72BR G ...
Page 51: ...51 KX FT72BR G ...
Page 52: ...CROSS REFERENCE TEST FUNCTIONS P 82 52 KX FT72BR G ...
Page 58: ...58 KX FT72BR G ...
Page 59: ...Normal Wave Patterns 59 KX FT72BR G ...
Page 61: ...CROSS REFERENCE NG EXAMPLE P 63 CHECK THE STATUS OF THE DIGITAL BOARD P 64 61 KX FT72BR G ...
Page 62: ...CROSS REFERENCE CHECK THE STATUS OF THE DIGITAL BOARD P 64 62 KX FT72BR G ...
Page 63: ...2 3 6 2 NG EXAMPLE 63 KX FT72BR G ...
Page 66: ...2 3 7 2 DEFECTIVE ITS INTEGRATED TELEPHONE SYSTEM SECTION 66 KX FT72BR G ...
Page 68: ...2 Troubleshooting Flow Chart 68 KX FT72BR G ...
Page 69: ...69 KX FT72BR G ...
Page 73: ...2 3 11 READ SECTION Refer to SCANNING BLOCK P 112 73 KX FT72BR G ...
Page 79: ...2 4 5 SERVICE MODE SETTINGS Example of a printed out list 79 KX FT72BR G ...
Page 85: ...3 2 HOW TO REMOVE THE OPERATION BLOCK 85 KX FT72BR G ...
Page 86: ...3 3 HOW TO REMOVE THE OPERATION BOARD AND LCD 86 KX FT72BR G ...
Page 87: ...3 4 HOW TO REMOVE THE BOTTOM FRAME AND ANALOG BOARD 87 KX FT72BR G ...
Page 88: ...3 5 HOW TO REMOVE THE DIGITAL POWER SUPPLY BOARD AND AC INLET 88 KX FT72BR G ...
Page 89: ...3 6 HOW TO REMOVE THE MOTOR BLOCK AND SEPARATION ROLLER 89 KX FT72BR G ...
Page 90: ...3 7 HOW TO REMOVE THE MOTOR AND GEARS OF MOTOR BLOCK 90 KX FT72BR G ...
Page 91: ...3 8 HOW TO REMOVE THE IMAGE SENSOR CIS 91 KX FT72BR G ...
Page 92: ...3 9 HOW TO REMOVE THE DOCUMENT FEED ROLLER 92 KX FT72BR G ...
Page 93: ...3 10 HOW TO REMOVE THE THERMAL HEAD 93 KX FT72BR G ...
Page 94: ...3 11 INSTALLATION POSITION OF THE LEAD WIRES 94 KX FT72BR G ...
Page 96: ...4 3 FLAT PACKAGE IC INSTALLATION PROCEDURE 4 4 BRIDGE MODIFICATION PROCEDURE 96 KX FT72BR G ...
Page 97: ...5 CIRCUIT OPERATIONS 5 1 CONNECTION DIAGRAM 97 KX FT72BR G ...
Page 99: ...5 2 1 General Block Diagram 99 KX FT72BR G ...
Page 109: ...5 4 2 BLOCK DIAGRAM 109 KX FT72BR G ...
Page 111: ...111 KX FT72BR G ...
Page 117: ...5 4 6 3 4 COPYING CROSS REFERENCE SENSOR SECTION P 72 117 KX FT72BR G ...
Page 132: ...5 10 1 CIRCUIT DIAGRAM 132 KX FT72BR G ...
Page 135: ...5 12 POWER SUPPLY BOARD SECTION 135 KX FT72BR G ...
Page 137: ...6 TERMINAL GUIDE OF THE ICs TRANSISTORS AND DIODES 137 KX FT72BR G ...
Page 138: ...7 FIXTURES AND TOOLS 138 KX FT72BR G ...
Page 140: ...8 2 UPPER CABINET SECTION 140 KX FT72BR G ...
Page 141: ...8 3 LOWER CABINET P C B SECTION CROSS REFFERENCE MOTOR SECTION P 142 141 KX FT72BR G ...
Page 142: ...8 4 MOTOR SECTION 142 KX FT72BR G ...
Page 143: ...8 5 ACTUAL SIZE OF SCREWS 143 KX FT72BR G ...
Page 144: ...9 ACCESSORIES AND PACKING MATERIALS 144 KX FT72BR G ...
Page 163: ...163 KX FT72BR G Y M KXFT72BRG ...