Brother MFC9100C Service Manual page 25

2.2.3 Purging mechanism
The purging mechanism is driven by the paper feed motor located at the left side of the main
chassis. The rotation of the paper feed motor is transmitted to the paper feed roller. At the right
end of the paper feed roller, the rotational torque is further transmitted via the arm 12.3 ASSY
located on the main chassis to the gear train (including the sun gear 16/32 and planet gear 20) on
the PF side frame R.
If the carriage travels from the left to right to reach the purge position, the lower left tab provided
on the back of the carriage turns fin "x" of the purge lever counterclockwise (when viewed from the
top), so the bottom end of the purge lever releases the purge switching arm. Accordingly, the
planet gear 20 will be engaged with the gear 20 and the rotational torque of the paper feed motor
will drive the purge cam.
On the contrary, if the carriage travels from the purge position to the left, the upper right tab on the
back of the carriage turns fin "y" of the purge lever clockwise. The purge lever's bottom end
pushes down the purge switching arm so that the planet gear 20 will be disengaged from the gear
20. The sun gear 16/32 will simple idle.
That is, when the carriage is in printing operation or the purge cam is in the home position, no
rotation of the paper feed motor is transmitted to the purge gear train; when the carriage is in the
purge position, the motor rotation is transmitted to the purge gear train which rotates the purge
cam.
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