Temperature Corrections; Overheat Protection - Ricoh J-P3 Service Manual

20 February 2004

Temperature Corrections

To prevent excessive glossiness caused by fusing temperature overshoot, the
following SP modes are available:
• 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, causing marks
on the output. To prevent this problem, we have the following SP modes:
• 1-996-004, 005: These SPs specify a limit, above which printing will not
start.

Overheat Protection

If the heating roller temperature is more than 220°C, the CPU cuts off the power to
the fusing lamp and SC543 occurs.
If the pressure roller temperature is more than 200°C, the CPU cuts off the power
to the fusing lamp and generates SC553 occurs.
If thermistor overheat protection fails, there are the thermostat for the heating roller
and two thermofuses for the pressure roller in series with the common ground line
of the fusing lamp.
• If the thermostat temperature becomes higher than 225°C, the thermostat
opens, removing power from the fusing lamp.
• If either of the two thermofuses temperature becomes higher than 126°C,
the thermofuse opens, removing power from the fusing lamp.
NOTE: These thermofuses make a series circuit.
In either case, the machine stops operation.
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FUSING