Canon NP6012F Service Manual page 70

3. Cleaning the Primary Charging Roller
a. Outline
The primary charging roller remains in
contact with the photosensitive drum at all
times; for this reason, it can collect dirt from
the photosensitive drum, possibly causing
unstable primary charging.
To prevent such a problem, the copier is
equipped with a cleaning mechanism for the
primary charging roller, thereby ensuring sta-
ble primary charging at all times.
Cleaning is executed depending on the
following two conditions:
9 Condition 1
Copies made since power-on are count-
ed (cumulative), and cleaning is executed
when 10 or more copies have been deliv-
ered. If the number of copies is less than 10,
the copy count is stored when the power is
turned dff, and the new count is added to it
when the power is returned.
l
Condition 2
Copies made since power-on are count- b. Operation
When the cleaning solenoid (SL5) turns on, ed, and icleaning is executed when the 20th
the cleaning pad is butted against the
copy hag been discharged. The copy count
primary charging roller to stat-l cleaning. is cleared when the power is turned off, and
Cleaning is executed during post rotation
the copy count starts newly when the power
and lasts about 1.5 set, making post is returned next time. When the count reach-
rotation longer than rotation without es 20 or higher, cleaning will be executed
cleaning. once again.
DC controller PCB
Photosensitive drum
Figure 3-315
3 - 32
COPVAIGHT 0 1995 CANONINC. CANON NP6012/NP6012F/NPS212 REV.1 SEPT.1995 PRlNTEDINJAPAN(IMPAIMtAUJAPON)