Ricoh A085, Manual

Page: 358 / 617

12.4 FUSING LAMP CONTROL
When the main switch is turned on the CPU starts sending a trigger pulse to
the fusing control circuit to turn on the fusing lamp.
When the CPU detects a fusing temperature of 175°C through the thermistor,
the copier starts fusing idling. When the fusing idling finishes, the warm-up
period is completed and the Ready indicator turns on. This should take less
than 110 seconds. If the fusing temperature is above 60°C when the main
switch is turned on, the copier does not go into the fusing idling mode.
When the fusing temperature reaches 180°C the CPU changes the fusing
lamp on/off check cycle from every 1 second to every 5 seconds.
The CPU also changes the fusing lamp on period every check cycle. The
change is calculated according to the result of the previous check. This
keeps the fusing temperature as close as possible to the target temperature
(185°C).
If the fusing lamp (830W) is turned on or off while the exposure lamp is on,
the power supplied to the exposure lamp may fluctuate, possibly degrading
the copy image.
To prevent this, the fusing lamp does not change while the exposure lamp is
on; it stays either on or off.
This copier controls the fusing temperature in zero cross control mode as a
standard. It can be changed to phase control mode by SP29 as necessary.
185°C
180°C
175°C
60°C
Time
Fusing
Lamp
ON
OFF
100S
5S 5S
Temp
Det
a
il
ed
Descriptions
12 February 1992 IMAGE FUSING
2-103