Fusing Temperature Control; Overview - Ricoh B039 Service Manual

IMAGE FUSING AND PAPER EXIT

6.13.5 FUSING TEMPERATURE CONTROL

Overview

The fusing temperature is controlled using the fusing thermistor [A].
The CPU checks the output from the fusing thermistor once a second. The CPU
compares the current and previous temperature, then decides the power-on ratio
for the next second. To maintain the target temperature, the CPU controls the
fusing lamp power-on ratio as shown in the following table (the temperature control
algorithm only works with whole numbers).
The fusing lamp works to maintain a target fusing temperature of 175°C during
copying.
Initializing
Sampling cycle: 1 second
Soft start setting: 3 cycles
Previous minus Current
–3°C or less
From –2°C to –1°C
0°C
From +1°C to +2°C
+3°C or more
B039/B040/B043
–2° ° ° ° C or
–3° ° ° ° C or
less
100%
100%
100%
100%
100%
Ratio (%): The proportion of time that the fusing lamp power is on
6-62
[A]
B039D506.WMF
Current minus Target
0° ° ° ° C
–1° ° ° ° C
50% 0%
50% 0%
50% 0%
50% 0%
50% 0%
+1° ° ° ° C or
+3° ° ° ° C or
+2° ° ° ° C
more
0% 0%
0% 0%
0% 0%
0% 0%
0% 0%
SM