Table of Contents
Advertisement
1 Nov. '87
- Overheat Protection 2-
In case the thermistor overheat protection circuit fails, a thermoswitch is in
stalled in series with the fusing lamp. If the temperature of the thermoswitch
reaches 169 degrees, the thermoswitch opens.
On
Fusing Lamp
o f f
The above illustration shows how the fusing lamp is controlled to warm up
the hot roller when the power is turned on.
When the main switch if turned on full power is applied to the fusing lamp.
When the hot roller temperature reaches 150 degrees, the ready beeper
sounds and the Start key turns green. At this time copying is possible.
Full power application continues until the temperature reaches 160 degrees.
At this time the CPU changes to a switching control cycle in which the fusing
lamp is turned on for 250 milliseconds and off for 500 milliseconds. Switch-
ing control continues until the temperature reaches 185 degrees. Switching
control is used for the final part of fusing warm-up to prevent excessive over-
shoot of the fusing roller temperature.
After warm-up is complete, the fusing lamp is turned on when the tempera-
ture drops below 184 degrees and it is turned off when the temperature rises
above 185 degrees.
T I M E
Advertisement
Table of Contents
