Fusing Temperature Control - Konica Minolta BIZHUB 750 Service Manual

21. FUSING SECTION
21.3.2

Fusing temperature control

The heating of the fusing roller /Up is made by the fusing heater lamp/1 (L2) and /2(L3) and the heating of the
fusing roller /Lw by the heater lamp/3 (L4).
The surface temperature of the fusing roller /Up is detected by the thermistors /1 (TH1) [2] and /2 (TH2) [1]. Tem-
perature of the fusing roller/Lw is not specifically detected. For TH1 of these thermistors, an NC sensor superior
in the speed of detection is employed.
The printer control board (PRCB) controls the fusing temperature as the DC power source/1 (DCPS1) turns L2
and L3 ON or OFF based on the surface temperature of the fusing roller/Up detected by TH1.
[1] Thermistor /2 (TH2)
A. Warm-up
While in the warm-up, the fusing heater lamp/1 (L2), /2 (L3), and /3 (L4) are turned ON. They are turned OFF
when the fusing roller/Up surface temperature reaches the specified value. However, L2, L3 and L4 are not
turned ON at the same time to prevent flickering.
B. While in the print or while in the stand-by
The setting temperature of the fusing roller /Up varies with the type of paper, its size, the print mode or other
conditions. A control is made by turning on and off the fusing heater lamp /1 (L2) and /2 (L3) so that a prescribed
temperature can be obtained at all times. However, L2, L3 and L4 are not turned ON at the same time to prevent
flickering.
C. Power save mode
There are 2 modes available for the power save mode: sleep mode and low power mode. In the sleep mode, the
power is not supplied to the fusing heater lamp/1 (L2), /2 (L3) and /3 (L4). In the low power mode, a control is
made by turning L2, L3 and L4 ON/OFF so that the temperature is kept at a prescribed set temperature lower
than that seen while in the stand-by mode. However, L2, L3 and L4 are not turned ON at the same time to pre-
vent flickering.
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[1] [2]
[2]
Theory of Operation Ver1.0 Aug.2005
Thermistor /1 (TH1)
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