Brother MFC-9420CN Service Manual

Confidential
3-34
(3) Control of the Fusing Temperature
Each roller of the fusing unit is controlled to maintain the appropriate temperature so that
toner will be fixed correctly onto the print paper.
<Basic Structure of Temperature Control (Fig.3-35)>
FLS: Thyristor to control the on/off operation of power supply to the
heat lamp.
THS1 / THS2: Thermostat to shut down the circuit for safety when it will be too
hot within the fusing unit FU.
TH: Temperature sensor to detect the surface temperature of the heat
roller (HR).
RY: Relay to prevent the further heating when it will be hotter than
the set point within the fusing unit FU.
GA/CPU: Process circuit to process the temperature signal
(micro computer).
CM1: Sensor circuit for temperature signal (for ACOFF signal).
CM2: Sensor circuit for temperature signal (for HON signal).
CM3: Sensor circuit for temperature signal (for processing).
Q: Sensor circuit for shut-down by the thermistor
(for THERR signal).
HR: Back-up roller.
<Signal Functions>
HON-N: To turn on/off the heater in side the fusing roller.
ACOFF: To turn off the relay RY1 when it is sensed too hot.
THERR: To detect the shut-down by the thermistor.
AD: To convert the temperature sensing signal to AD.

Brother MFC-9420CN Specifications

General

Print technology	Laser
Maximum resolution	1200 x 2400 DPI
Economical printing	Yes
Print speed (black, normal quality, A4/US Letter)	31 ppm
Print speed (color, normal quality, A4/US Letter)	8 ppm
Digital sender	No
Number of print cartridges	4
Scanner type	Flatbed scanner
Scanner features	Scan to: e-mail, image, OCR, file
Copier resize	25 - 400 %
Maximum copy resolution	600 x 600 DPI
Maximum number of copies	99 copies
Copy speed (black, normal quality, A4)	31 cpm
Copy speed (color, normal quality, A4)	8 cpm
Faxing	Color faxing
Fax memory	500 pages
Modem speed	33.6 Kbit/s
Fax speed dialing (max numbers)	200
Total input capacity	750 sheets
Maximum input capacity	250 sheets
Auto document feeder (ADF) input capacity	35 sheets
Maximum internal memory	576 MB
Bundled software	ScanSoft PaperPort Presto! PageManager
I/O ports	IEEE-1284 USB 2.0
Dimensions (WxDxH)	483.5 x 514 x 530 mm
Printer management	BRAdmin Professional, MIB-II
Networking features	10Base-T/100Base-TX
All-in-one functions	Fax, Scan
Color all-in-one functions	copy, fax, print, scan
Compatible operating systems	Windows 98(SE)/ Me/ NT WorkStation 4.0/ 2000 Professional/ XP Mac OS 9.1 - 9.2, Mac OS X 10.2.4+
Sustainability certificates	ENERGY STAR
Power consumption (standby)	85 W
Power consumption (PowerSave)	16 W
Power consumption (average operating)	1090 W
Operating temperature (T-T)	10 - 32 °C
Operating relative humidity (H-H)	20 - 80 %
Market positioning	Business