User Guide

CHAPTER 4 IMAGE FORMATION SYSTEM
COPYRIGHT © 1999 CANON INC. CANON NP6512/6612/7120/7130/7130F REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON) 4-30
C. Detecting Waste Toner
The drive occurring as the result of rotation of the photosensitive drum is transmitted to the
drum gear, coupling gear, and waste toner feed blade drive gear in sequence. The waste toner
collected by the cleaning blade is sent to the rear of the inside of the drum unit.
The coupling gear is forced against the drum gear and the waste toner feed blade by means of
a spring, and serves to transmit the drive from the main motor to the toner feed blade drive gear
through the drum gear.
When the inside of the drum unit becomes full of waste toner and, as a result, the rotation of the
waste toner feed blade starts to drag, the engagement of the waste toner feed blade drive gear and
the coupling gear breaks, moving the detecting lever of the waste toner sensor (PS5). This condi-
tion will cause the DC controller PCB to find out that the drum unit is full of waste toner, conse-
quently flashing the Replace Durm Unit message on the control panel.
Copying operation will still be possible even while the Replace the Drum Unit message is
flashing. The DC controller PCB does not retain the memory of the level of waste toner, and the
message will not come back when the power has been turned off and then on again.
DC controller PCB
Replace drum
unit indicator
Waste toner
sensor
(PS5)
Toner feeding blade
Coupling gear
Photosensitive drum
Waste toner
signal
(TNFULL)
Waste toner
Figure 4-203
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