Temperature Corrections - Ricoh B202 Service Manual

Temperature Corrections

The following SP modes are available to prevent excessive glossiness caused by
fusing temperature overshoot:
• 1-913: Fusing temperature is reduced after this number of pages during the
job.
• 1-914: This shows how much the temperature is reduced
If a job using OHP or thick paper starts while the fusing unit is still warm, the fusing
temperature could be higher than the target for this type of paper. This can cause
marks to show on the output. The following SP modes prevents this problem:
• 1-996-4, 5: These SPs specify a limit, above which printing will not start.
Overheat Protection
The CPU cuts power to the fusing lamp at the following times:
• The heating roller temperature becomes higher than 250°C for two seconds
or more
• The pressure roller temperature becomes higher than 210°C for five seconds
or more.
SC543 for the heating roller or SC553 for the pressure roller are displayed for
these conditions.
The following components are used if the thermistor overheat protection system
fails.
• Two thermostats for the heating roller and two thermofuses for the pressure roller
in series with the common ground line of the fusing lamp.
• If one of the thermostat temperatures becomes higher than 234°C, it opens
and cuts power from the fusing lamp.
If the other thermostat temperature becomes higher than 235°C, it also
opens and cuts power from the fusing lamp.
• If either of the two thermofuses temperature becomes higher than 154°C, the
thermofuse opens and cuts power from the fusing lamp.
NOTE: These thermofuses make a series circuit.
In either case, the machine stops operation.
SM 6-93
FUSING
B202/B178/B180