Fixing Temperature Control - Konica Minolta 7020 Service Manual

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FIXING UNIT
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Fixing Temperature Control

RL
AC
DCPS
The fixing heat roller is heated by lamps L2 (fixing heater
lamp 1) and L3 (fixing heater lamp 2). The PRDB (printer
drive board) detects the temperature on the roller by
means of TH1 and TH2 (fixing temperature sensor 1 and
2), and controls L2 and L3 accordingly via the DCPS (DC
power source).
1. Operation
a. Temperature control
(1) Warm-up
The PRDB turns on the fixing heater lamp circuit
within the DCPS immediately when power comes on,
and holds L2 and L3 on until the fixing heat roller
reaches the specified temperature. L2 and L3 have
different light (heat) distribution characteristics (see
illustration below), and control temperature through
TH1 and TH2.
Heat roller
Front
TH2
L2 CONT
L3 CONT
RL CONT
L2
L2 DRIVE
TH1 ANG
L3
L3 DRIVE
SGND
TS
TH2 ANG
SGND
PRDB
L2
TH1 L3
L2 light distribution characteristics
TH1
TH2
L3 light distribution characteristics
Once warm-up has completed, the PRDB switches
L2 and L3 ON and OFF as necessary to maintain the
set temperature.
(Warm up time)
4
Other than 7035: Within 30 seconds (from room
Rear
7035/7135:
(2) Idling
L2 and L3 go ON/OFF repeatedly so as to maintain
the temperature between 191°C and 187°C
(U.S.A.)/202°C and 187°C (Europe).
2-K-2
Bright
Dark
Bright
Dark
temperature of 20°C).
Within 45 seconds (from room
temperature of 20°C).