41309401TH Rev.4
327 /
Figure A.16 (3/4) Fuser Unit Temperature Control
IC2
47
59
27
Heater
on/off circuit
IOGA4
HEAT-N
46F
0V
0V
ACIN
F1
THCHK
5V
TRA1
AOUT
PC4
MPW1446/MPW1546
Thermostat
Thermistor
Heater
Fuser unit
THCHK
THON
IOGA4
P2H Board
THCHK
THON
+5V
ACON
CN7
10
CN6
13
IC2
HEATON
2)
Fuser unit temperature control
The heater in the fuser unit is controlled by the thermister, IOGA4 keeps the heater roller
surface within a prescribed temperature range. The IOGA4 supervises the status of
THCHK (A/D converter input section) periodically, turning HEATON signal on and off
according to IOGA4 of THCHK status to exercise temperature control.
At power on time, the IOGA4 switches the output signal THON from pin 59 (between high
and low states) to check for a blown or shorted thermister according to the status of the
THCHK signal.
A built-in thermostat in the fuser unit prevents the heater from being overheated in event
of failures in the thermister, or temperature control circuit, etc.
Figure A.16 (3/4) shows the fuser unit temperature control.
Note: Heater control
Temperature of the heater at the time of printing is 150 ˚C to 180 ˚C. This temperature
is maintained by controlling the on and off operation of heater according to the input
of the thermister converted into analogue-digital (A/D) values by the IOGA4.
2)-1
Heater control
The ACON control signal on the secondary side is transmitted to the primary side via
PC4 to turn triac TRA1 for AC voltage supply to the heater.
Summary of Contents for OKIFAX4550
Page 156: ...41309401TH Rev 4 156 Figure 4 2 Appearance of the OKIFAX4550 OKIOFFICE87...
Page 428: ...41309401TH Rev 4 428 SECTION 1 CABINET ASSEMBLY OKIFAX4550 OKIOFFICE87...
Page 431: ...41309401TH Rev 4 431 SECTION 2 UNIT PRINTER...
Page 433: ...41309401TH Rev 4 433 SECTION 3 UNIT 051 OPE PANEL...
Page 435: ...41309401TH Rev 4 435 SECTION 4 OPEPANEL OPERATION PANEL ASSEMBLY...
Page 437: ...41309401TH Rev 4 437 SECTION 5 FRAME ASSEMBLY SCANNER L...
Page 439: ...41309401TH Rev 4 439 SECTION 6 PLATE ASSEMBLY SCANNER B...
Page 441: ...41309401TH Rev 4 441 SECTION 7 PLATE ASSEMBLY SCANNER R...
Page 443: ...41309401TH Rev 4 443 SECTION 8 FRAME ASSEMBLY SCANNER U...
Page 445: ...41309401TH Rev 4 445 SECTION 9 COVER ASSEMBLY TOP...
Page 447: ...41309401TH Rev 4 447 SECTION 10 PLATE ASSEMBLY BASE...
Page 449: ...41309401TH Rev 4 449 SECTION 11 PRINTER BASE FRAME UNIT Heat assy...
Page 452: ...41309401TH Rev 4 452 SECTION 12 PRINTER HEAT ASSY...
Page 454: ...41309401TH Rev 4 454 SECTION 13 CABLES...
Page 457: ...41309401TH Rev 4 457 46F PCB Assy 1 9 41196601...
Page 466: ...41309401TH Rev 4 466 R46 PCB Assy 1 10 41033201...
Page 476: ...41309401TH Rev 4 476 04W PCB Assy 1 3 40071401...
Page 479: ...41309401TH Rev 4 479 EN9 PCB Assy 1 6 41144301...
Page 485: ...41309401TH Rev 4 485 INU PCB Assy 41144501 US 1 4 41144502 INT 1 5...
Page 493: ...41309401TH Rev 4 493 MPW1546 120V PCB Assy 1 5 SIPS1303...
Page 498: ...41309401TH Rev 4 498 MPW1446 230V PCB Assy 1 6 SIPS1302...
Page 504: ...41309401TH Rev 4 504 P2H PCB Assy 1 4 40599101...
Page 508: ...41309401TH Rev 4 508 P6L PCB Assy 1 3 40386701...
Page 511: ...41309401TH Rev 4 511 G4N PCB Assy 1 5 41033701...
Page 585: ...41309401TH Rev 4 585 Figure H 7 1 2 RTC Time Read Figure H 7 2 2 RTC Time Set...
Page 587: ...41309401TH Rev 4 587 Figure H 9 Figure H 10 1 3...
Page 588: ...41309401TH Rev 4 588 Figure H 10 2 3 Figure H 10 3 3...
Page 589: ...41309401TH Rev 4 589 Figure H 11 1 3 Figure H 11 2 3...
Page 590: ...41309401TH Rev 4 590 Figure H 12 Figure H 11 3 3...
Page 591: ...41309401TH Rev 4 591 Figure H 13 1 2 Figure H 13 2 2...
Page 592: ...41309401TH Rev 3 592 592 Figure H 14 1 2 Figure H 14 2 2...
