- HP Printer User Manual

114 MFP unit explanation ENWW
Fuser temperature control
The fuser roller (upper) is heated by L2
(fuser heater lamp 1) and L3 (fuser heater
lamp 2), and the fuser roller (lower) is heated
by L4 (fuser heater lamp 3). The PRCB
(printer control board) detects the
temperature of the fuser roller (upper) using
TH1 (fuser temperature sensor/1) and TH2
(fuser temperature sensor/2), and controls
L2 and L3 via DCPS (DC power supply unit).
1 Operation
a Temperature control
The PRCB (printer control board) turns
on the fuser heater lamp circuit in DCPS
as soon as the SW2 (sub power) is
turned on, holding L2 (fuser heater
lamp/1), L3 (fuser heater lamp/2), and
L4 (fuser heater lamp/3) lit until the
fuser roller (upper) reaches the
specified temperature. L2, L3, and L4
are turned on/off under the control of the
TRC1 (triac/1), TRC2 (triac/2) and
TRC3 (triac/3).
b Protection against abnormal
temperature rise
Thermostats are used to prevent the
temperature of the fuser rollers from
rising abnormally. TS1 (thermostat/U)
and TS2 (thermostat/L) are used for the
fuser roller (upper/lower). As these
thermostat are of the noncontact type,
those do not touch the fuser roller
(upper/lower).
The operating temperature of the
thermostats are as follows:
TS1: Opens at 180° C
TS2: Opens at 110° C
2 Signals
a PRCB input signals
1 TH1+,- (TH1 to PRCB)
Fuser roller (upper) temperature
detection signal
This signal is used to control the
temperature of the fuser roller (upper)
and to detect abnormal temperature
rise.
DCPS
PRCB
FIXHT1_CONT
FIXHT2_CONT
FIXHT3_CONT
MAINRL_CONT
AC(H)
AC(C)
TH1+
TH1-
TH2+
TH2-
5V2
S.GND
TH2
TH1
TRC1
RL1
L3
L4
L2
TS1
TRC2
TRC3
24VDC
TS2