Konica Minolta 7020 Service Manual page 91

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(3) Copying
(When feeding from any trays other than the by-pass
tray)
Temperature control during copying goes ON/OFF
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repeatedly so as to maintain temperature at about
194°C. If the selected size is small (B5R, B6R, A5R,
or 5.5x8.5R), then although L2 and L3 both go ON/
OFF repeatedly control is for the most part
implemented by L2 only (so as to prevent
overheating at the ends of the fixing roller).
(When feeding from the bypass tray)
The temperature is held approximately 10°C higher
than the temperature indicated above. Where OHP
has been selected using the application function,
control is the same as for normal copying.
(Doble sided copying)
Temperature is held about 5°C lower that the
temperature used when feeding from any tray other
than the by-pass tray.
(4) Low-power mode
L2 and L3 go ON/OFF repeatedly so as to maintain
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the temperature at about 85°C (about 170°C in the
case of the 7035/7135, about 150°C in the case of
the 7122).
The temperature for low power mode can be changed
by 25 mode DIPSW.
b. Protection against abnormality
A thermostat (TS) in contact with the fixing heat roller
protects against overheating of the roller. The
operating temperature of TS is shown below.
TS: Approximately 220°C
2. Signals
a. Input signals
(1) TH1 ANG (TH1 −> PRDB)
TH1 output signal.
Outputs a voltage that varies according to the surface
temperature at the center of the fixing heat roller. This
signal is used both for normal temperature control
and for detection of heating error (overheating, etc.).
(2) TH2 ANG (TH2 −> PRDB)
TH2 output signal.
Outputs a voltage that varies according to the surface
temperature at the ends of the fixing heat roller. This
signal is used both for normal temperature control
and for detecting of heating error (overheating, etc.).
b. Output signals
(1) L2 DRIVE (DCPS −> L2)
AC (N) power line for L2.
Sets AC power on and off in accordance with the L2
CONT signal.
(2) L3 DRIVE (DCPS −> L3)
AC (N) power line for L3.
Sets AC power on and off in accordance with the L3
CONT signal.
(3) L2 CONT (PRDB −> DCPS)
L2 ON/OFF control signal.
[L]: L2 ON
[H]: L2 OFF
(4) L3 CONT (PRDB −> DCPS)
L3 ON/OFF control signal.
[L]: L3 ON
[H]: L3 OFF
2-K-3
FIXING UNIT