Ricoh SP 8400DN Field Service Manual page 1432

7.Detailed Descriptions
between the fusing unit and the toner bottle, to suppress excessive temperature rise of the toner bottle.
The front development cooling fan takes in air from the front, and blows air over the PCDU to cool it.
Cooling of Fusing Unit
Air taken in from the paper exit fan at the front is discharged from the fusing fan at the rear to outside the
machine. By cooling the paper immediately after fusing, it is used for not only cooling of the paper exit sensor but
also reduction of stored heat of stack paper and reduction of curl are realized. This also serves to prevent dew
condensation of the paper discharge guide sheet. As a measure against odor, an odor filter is installed downstream
from the fusing fan.
Crisis management when temperature rises in the Printer
In order to suppress excessive temperature rise in the printer and maintain equipment quality, a temperature
detection sensor (imaging temperature sensor (thermistor)) [A] is installed in the printer. The imaging temperature
sensor (thermistor) detects the temperature environment in the printer, and controls cooling.
Overview of cooling operation in the machine
The temperature in the machine is detected during output and after output, and the interior of the machine is
cooled by fan operation (stepwise operation of fan, prolonged fan rotation after paper has passed through)
according to the temperature inside the machine.
However, if the temperature inside the machine rises significantly due to passing a large volume of paper, in
addition to fan operation, the CPM is specified to control the temperature in the machine.
The Conditions of Fans Operation
The following table illustrates how/when the fans operate under the specific conditions of the main machine.
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