2. Fan motor control
This printer has 4 heat exhausting fans and an air intake fan. They are DC brushless motors.
The figure below shows the fan motor control circuit.
Figure 2-2-14
When the power switch of the printer is turned ON, the CPU (IC201) on the DC controller sets
the No.53 pin to "H" and rotates the multi-purpose tray fan (FM5) at half speed for about 15 sec-
onds. The CPU sets the No.65 pin to "H" via the gate array (IC202), and rotates the power sup-
ply fan (FM1), fixing unit/scanner fan (FM2), electrical unit fan (FM3), and fixing unit fan (FM4)
at half speed.
When it receives a /PRNT signal from the video controller, the CPU rotates FM1, FM2, FM3,
and FM4 at full speed and FM5 at half speed (full speed in case of duplex printing). When the
main motor drive stops after printing, the CPU rotates FM1, FM2, FM3, and FM4 at full speed
for about 30 seconds then at half speed. The CPU rotates FM5 at half speed for about 30 sec-
onds (full speed for about 30 seconds in case of duplex printing).
The drive voltages output from the fan motor drive circuit and multi-purpose tray fan motor
2 - 24
CHAPTER 2
