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operations and
timing
V.
POWER
SUPPLY
A.
AC
Driver
DC
Power
Supply
1.
Outline
The
AC
driver/DC
power
supply
PCB
is
supplied
with
AC
power
when
the
door
switch
(SW2) and
the
power
switch
(SW1)
go
ON.
On
the other
hand
the
DC
power
supply
supplies the
main body
with
36
VDC,
24
VDC,
and
5
VDC.
36
VDC
is
used
to
drive
the
scanner
motor
(M2),
and 24
VDC
is
used
to drive
fans
and
solenoids
as
well
as
high-voltage
transformer (HVT);
5
VDC
is
used by
the
sensors
and
ICs
on
the
DC
controller
PCB.
2.
DC
Power
Supply
Circuit
The
AC
voltage
is
lowered
to
32
V
by
the
external
transformer
(T1
)
and
sent
to
the
DC
power
supply/AC
driver
PCB.
The
lowered
voltage
is
then
rectified to
36
VDC
and
converted
to
24
VDC
and 5
VDC
by two
regulators.
These
regulators
serve
to
prevent
overcurrent
and
help maintain the output
voltage against
fluctuations
in
the voltage
of
the
power
supply.
The
DC
power
supply/AC
driver
PCB
is
equipped
with
a
zero-cross
(ZXDP)
signal
generator
circuit;
the
circuit
generates
zero-
cross
signals
and sends them
to
the
DC
controller
for
control of
the
fixing
heater
temperature
and
the
copying sequence.
'E261'
is
indicated
on
the
control
panel
when
an
error
is
identified
in
the zero-cross
(ZXDP)
signal.
3.
AC
Driver Circuit
The
DC
power
supply/AC
driver
PCB
has
AC
driver
circuit
and,
based on
the signals
from
the
DC
controller
PCB,
controls the
SSRs
and
relays
on
the
DC
power
supply/AC
driver
PCB
to drive
AC
loads.
If
the
DC
controller
PCB
detects
an
error,
the
ACOFF
signal
is
generated
to
turn the
relay
(S105) on
the
DC
power
supply/AC
driver
PCB
OFF,
thereby
shutting
off
the
power
to
the
CVR
and
the
fixing
heater.
When
the
power
is
shut
off,
switch the
copier
OFF, and
identify
the
cause;
then,
switch the copier
OFF.
Note
that
repeated
short-circuiting
and
resetting
can cause
the
built-in
fuse
to
blow.
COPYRIGHT©
1992
CANON
INC.
CANON
HP-1SS0
REV.1
SEPT. 1992
PRINTED
IN
JAPAN
(IMPRIME
AU
JAPON)
3-39
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