Canon NP6012 Service Manual page 80

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5. Drum Unit Replacement Time
Automatic Indication Mechanism*
*Only for a model with the drum unit
replacement time automatic indication func-
tion.
a. Outline
This mechanism is used to indicate
when the drum unit must be replaced based
on the number of copies made. A PGP PCB
is provided inside the drum unit to inform the
DC controller when the drum unit must be
replaced.
When the time for the replacement of
the drum unit approaches, the DG controller
PCB flashes the Replace Drum Unit indica-
tor on the control panel; when the time for
the replacement comes, the DC controller
turns on the Replace Drum Unit indicator on
the control panel, and indicates 'CC'
(Change Cartridge) on the copy/count indi-
cator after making 100 copies.
The copy may have a drum unit which
accommodates this function or one which is
not designed so. In addition, if you install a
drum unit which does not accommodate the
function in a copier model which is designed
for the function, copying operation will be
suspended while 'CC' (Change Cartridge) is
indicated on the count/ratio indicator.
Control panel
DC controller
PCB
b. Operation
¢ Drum Unit Installed
When the drum unit is installed and the
power is turned on, the DC controller reads
the following four types of data from the
PGP PCB and stores them:
1 serial number of drum unit (recorded on
PGP PCB)
2 copy count
primary charging voltage (DC) correction
value
4 drum sensitivity current correction value
If the DC controller PCB cannot find a
serial number or finds a serial number which
does not belong to the copier, it turns on the
Replace Drum Unit on the control panel and
suspends copying operation while indicating
'CC' on the count/ratio indicator.
Drum unit
(model with automatic
indication of drum unit
replacement time only)
PGP PCB
Figure 3-319
COPYRIGHT © 1995 CANON INC.
CANON NP6012/NPGO12F/NP6212 REV.1 SEPT. 1995 PRINTED IN JAPAN (IMPRIME AU JAPON)
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