Ricoh B089 Service Manual page 127

Fusing Lamp Control
Turning on and off the fusing lamp power causes fluorescent light in the room to
flicker. To reduce the flickering, use the following SP modes.
Fusing temperature detection cycle (SP mode 1-108)
The CPU checks the output from the fusing thermistor once a second (default
setting). The CPU compares the current and previous temperatures. Based on the
result, it then decides how long the fusing lamp power should be on during the next
one-second interval (also, if the current temperature is too high, the power will not
be needed).
Starting and stopping the fusing lamp power every second causes fluorescent
lighting in the room to flicker. To reduce this flickering, use SP1-108 to change the
cycle from 1 second to 3 seconds.
Fusing soft-start
In addition, whenever the fusing lamp power switches on, full power is applied to
the fusing lamp gradually, not all at once. This prevents the power in the room from
dropping suddenly. This feature is known as "Soft Start". The machine does this by
gradually allowing more power to the fusing lamp over a number of zero-cross
cycles of the ac supply. The diagram below shows full power being applied
gradually over the duration of 3 zero-cross cycles. Soft start occurs every time the
fusing lamp power switches on (i.e., at some time during every second), not just at
the start of the print job.
NOTE: This feature is effective to counter flickering lights. However, generated
noise increases if the setting is changed from the default. If a radio or a TV
is close by the machine, the noise may have some effect on the image or
sound.
SM
IMAGE FUSING AND PAPER EXIT
2-67
B027D512.WMF
B089/B093