Canon NP1550 User manual

NP1550
SERVICE
MANUAL
COPYRIGHT CANON INC.
PRINTED IN IAPAN
Canon
FY8-13BN-010

IGENERAL DESCRIPTION I
I. FEATURES
1
.
Copies as large as A3 in size (DIRECT) may be made, and the copyboard is of afixed type.
•Although compact in design the copier enables making copies as large as A3 in size in the
DIRECT mode.
•The copyboard is of afixed type so that pages of abook may be copied with much ease.
2. Zooming between 50% and 200%.
•Copies may be made in reproduction rations of between 50% and 200%, selectable in 1%
increments.
3. Front loading for faster supply of paper.
•Paper is loaded from the front of the copier so that the cassette may be replenished with
paper without wasting time. The design also saves space.
4. Single component fine particle toner for high resolution.
•Copies are developed using the single component toner projection method. Further, the
copier uses toner of extremely fine particles for enhanced image quality.
5. Multifeeder (stack bypass) pick-up.
•As many as 50 copies (80 g/rri) may be made continuously using the multifeeding
mechanism.
COPYRIGHT© 1992 CANON INC. CANON NP-1550 REM JAN. 1992 PRINTED IN JAPAN (IMPRIMEAUJAPON) 1-1

IGENERAL DESCRIPTION I
II. SPECIFICATIONS
A. Type
Body Desktop
Copyboard Fixed
Light sourse Halogen lamp (300W)
Lens Zoom lens :
Photosensitive medium OPC
B. System
Reproduction Indirect electrostatic method
Charging Corona
Exposure Slit (moving light source)
Copy density adjustment Auto or Manual
Development Dry
Pick-up Automatic Exclusive cassette
Manual Multifeed
Transfer Corona
Separation Curvature and Static eliminator
Drum cleaning Blade
Fixing Heat roller (900W)
C. Performance
Type of document Sheet,Book,3-D object(2 kg)
Document size A3 max.
Wait time 75sec(approx.;at20°C)
First copy 9.4 sec (A4, AE ON/OFF, 1:1)
Continuous copying 99 copies
Copy size A3(max.),A6(min,;148x105 mm)
Type of
copy
paper
Cassette Plain paper(64 to 80 g/m2),Tracing paper,
Colored paper
Multifeed tray Plain paper(64 to 128 g/m2), Tracing paper*, Colored
paper, OHP film*, Postcard, Label sheet
*Use of tracing paper may cause double feeding. If thin paper or OHP film, feed one sheet at atime.
1-2 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.O JAN.1992 PRINTED IN JAPAN (IMPRIME AU JAPON)

IGENERAL DESCRIPTION I
Two-sided
copying Multifeed tray Plain paper(64 to 128 g/m 2), Colored paper, Postcard
Overlay
copying Multifeed tray Plain paper(64 to 128 g/m 2
), Colored paper, Postcard
Cassette
Claw Provided.
Standard 27 mm deep(about 250 sheets of 80 g/m 2paper)
Universal None.
Copy tray 100 sheets(approx.; A4, 80 g/m2
)
Non-image
width
(1st side)
Leading edge 2.0 ±1.5 mm or less
Left/Right 2.5 ±1 .5 mm or less
Auto clear Provided. (2 min, standard)
Auto shutoff None.
Option ADF-A1 ,CT unit, MS-A1 ,Stapler Sorter-B1 ,CC-V
D. Others
Power
supply
_^_— "Serial Numbers
220V 50Hz UBN XXXXX
240V 50Hz QBN XXXXX
Power
con-
sumption
Maximum 1.5kW or less
Standby 0.1 48 kWh (Reference value)
Continuous copying 0.64 kWh (Reference value)
Noise Copying 55dB or less (sound power level
as prescribed by ISO)
Standby 40dB or less
Ozone 0.05ppm or less (UL standards.)
Di-
mensions
Width 697mm
Depth 617mm
Height 391mm
Weight 50.6kg
Operating
environ-
ment
Temperature 15.0°Cto30.0°C
Humidity 5% to 80%
Atmospheric pressure 0.6 to 1
Others Keep copy paper wrapped to protect against moisture.
COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.0 JAN. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON) 1-3

IGENERAL DESCRIPTION I
Reproduction mode Paper size Cassette Copies/min
DIRECT
A3 (297x420mm) A3 9
A4 (210x297mm) A4 15
B4 (257x365mm) B4 10
B5 (182x257mm) B5 17
A5R (210x149mm) A5R 16
REDUCE I50% ^^^
II A3^A4 A4R 10
ENLARGE IA4-A3 A3 9
II 200% ^^^^^
1-4 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.0 JAN. 1992 PRINTED IN JAPAN (IMPRIIIE All JAPON)

IGENERAL DESCRIPTION I
III. NAMES OF PARTS
A. External View
(D -© ®©Copy tray
©Copyboard cover
@Control panel
@Power switch
©Cassette
©Delivery cover
Figure 1-1
©Copyboard glass
©Multifeeder cover
©Multifeeder tray
©Developing assembly
release lever
©Feeder assembly release
lever
©Drum unit
©Fixing assembly knob
COPYRIGHT© 1992 CANON INC. CANON NP-15S0 REM JAN.1992 PRINTED IN JAPAN (IMPRIME AU JAPON) 1-5

IGENERAL DESCRIPTION I
B. Cross Section
©©® © .©
©No. 3mirror
©No. 2 mirror
(3) No. 1mirror
®Scanning lamp
©Copyboard glass
©Copyboard cover
©Lens
®Pre-exposure lamp
©Primary corona assembly
)No. 6 mirror
)No. 5mirror
)No. 4mirror
)Multifeeder tray
)Developing assembly
)Feeder roller 1
)Registration roller
)Pick-up roller
)Feeder roller 2
Figure 1-3
&Transfer corona assembly
(Photosensitive drum
)Cassette
)Feeder assembly
)Exhaust fan
)Fixing assembly
)Delivery roller
1-6 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON)

IGENERAL DESCRIPTION I
IV. OPERATION
A. Control Panel
©©
(D ©
Figure 1-4
©SORT/GROUP key
Press it to select the sort, group, or non-
sort mode. The indicator remains unit
when the non-sort mode is selected.
^- sorting
2- grouping
©PAGE SEPARATION key
Press it to select the page separation
mode.
(D JAM indicator
®CONTROL CARD indicator
©ADD PAPER indicator
©ADD TONER indicator
©COPY COUNT/RATIO indicator
It indicates the reproduction ratio when
the %key is pressed.
®COPY START key
•glows orange when the copier is not
ready for copying.
•glows green when the copier is ready
for copying.
®RESET key
Press it to reset the copier to its default
settings.
Default Settings
•copy count 1
•DIRECT
•AE (may be turned OFF using 'C15' of
service mode)
•non-sort
»CLEAR/STOP key
)STANDBY key
)NUMERIC keypad
»%key
Press it to check the reproduction ratio
using the copy count indicator.
The display changes to the copy count 2
sec after the key is released.
)ZOOM key "
Press it to select desired reproduction
ratios between 50% and 200% in 1%
increments.
DAUTO RATIO key
Press it to select or deselect the auto
reproduction ratio mode.;
The key is effective when the ADF is attached.
iPAPER SELECT key
Press it to select the cassette or multifeeder
as the source of paper.
)PAPER SELECT/JAM indicator
ALED goes ON to indicate the location of
the paper or flashes to indicate the location
of the jam, if any.
DENLARGE key
IDIRECT key
JREDUCE key
DAE (automatic exposure (density) adjust-
ment) key
DCOPY DENSITY lever
COPYRIGHT© 1992 CANONINC. CANON NP-1550 REV.1 SEPT. 199! PRINTED IN JAPAN (IMPRIME All JAPON) 1-7

IGENERAL DESCRIPTION I
B. Basic Copying Operation
1
)
Set the power switch to ON (I).
a) If the temperature of the fixing roller is
too low for copying, the indicator of
the COPY START key will blink green.
b) When the temperature of the fixing
roller becomes high enough for
copying, the indicator will glow green.
c) The normal waiting time at room
temperature (20*C) is about ,75
seconds.
2) Raise the copyboard cover, place an
original on the copyboard with the side to
be copied facing downward, and align it
with the size indication.
3) To adjust the copy density manually, the
AE key indicator should be OFF; press
the key once if it is ON. Set the COPY
DENSITY lever to suit the original.
4) Check the size of paper in the cassette,
a) If the cassette does not have the
desired size of paper, remove it and
install acassette with the desired
size.
5) Set the required number of copies (1 to
99) using the NUMERIC keypad and
confirm that the correct number appears
on the COPY COUNT/RATIO indicator,
a) If an error was made in inputting the
number of copies, press the
CLEAR/STOP key and reset the
number of copies.
6) Press the COPY START key
a) To stop acontinuous copying operation,
press the CLEAR/STOP key or RESET
key. The copier will complete the copy in
progress, then stop.
The COPY COUNT/RATIO indicator
will display the initially set copy
quantity.
b) It is possible to switch from automatic
exposure control to manual density
adjustment at any time from the start of
copying to the completion of the final
copy. However, it is not possible to
switch from manual density adjustment
to automatic.
Example:
If the copy is too dark or too faint using AE,
cancel AE and vary the copy density with the
COPY DENSITY lever.
c) If the ADD PAPER indicator goes ON
during copying, the copier will stop.
Refill the cassette and press the COPY
START key. The remaining number of
copies will be made automatically.
d) If the copier has aADF, place adocument
(original) on the document tray. The
document will be fed automatically and
copying will start.
e) If ^no other operation is performed, the
copier will return to the STANDARD
mode approximately 2minutes after it
completes acopy or after the last key
operation.
C. PiCk-Up from Multifeeder
1
)
Set documents on the copyboard.
2) Press the PAPER SELECT key to select
the multifeeder.
3) Open the multifeeder tray.
4) Open the multifeeder cover.
5) Set the slide guide to the size of the copy
paper.
6) Set copy paper.
•As may as 50 sheets (80 g/m) may be
set:
Close the multifeeder cover.
Set the desired reproduction ratio using
the DIRECT, REDUCE, ENLARGE, or
ZOOM key.
Cancel the AE mode, and set the COPY
DENSITY lever if manual adjustment of
the density is desired.
10) Enter the number of copies using the
NUMERIC keypad.
11) Press the COPY START key.
7)
8)
9)
1-8 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON)

IGENERAL DESCRIPTION I
D. Two-Sided Copying
Copy one side of a2-sided original.
Invert the original so that the same edge
faces the front. >Invert the copy in the same
way (front edge facing the front) and feed it
into the copier.
a) Use dry, uncurled paper.
b) Use paper in the weight range 60 to
128g/rri
c) When making two-sided copies, only
one image can be made on each
side of the copy paper.
d) Both overlay and two-sided copies
cannot be made on the same sheet
of copy paper.
Back edge
Front edge 01=1
Back edge
Front edge
Figure 1-5
E. Overlay Copy Operation
By changing the developing assembly, a
2-color copy can be made on the same side
of the copy paper.
a) Use paper in the range of 60 to 128 g/m
b) When making an overlay copy a
maximum of two images can be
made on one side of the copy paper.
c) Overlay and two-sided copies cannot
be made on the same sheet of copy
paper.
F. Autostart
The auto start mechanism may be made
use of while the copier is in the wait mode
(COPY START key blinking green); i.e., after
it is switched ON or after the standby mode
is cancelled.
Set adocument while the copier is in the
wait mode, and select the copy mode; then,
press the COPY START key.
The COPY START key changes from
blinking green to orange to indicate that the
auto start mechanism has been activated.
The copier starts making copies as soon
as it enters the standby mode using the
selected copy modes.
The auto start mechanism may be can-
celled by pressing the CLEAR/STOP or
RESET key. ;
G. Replacing the CT Unit
1
)
Open the front door.
2) Swing the developing assembly release
lever counterclockwise.
3) Pull the developing assembly forward.
4) Grasp the handle of the developing
assembly, and gently raise it.
Figure 1-6
5) Place the CT unit gently on the develop-
ing assembly guide rails and push it in
the copier.
6) Shift the developing assembly release
lever clockwise until it is horizontal.
7) Close the front door.
i. Do not tilt or handle the developing
assembly or the CT unit roughly,
ii. Do not place the developing assembly
'i •-•^p^W^'^W^W*^* box or in
the pedestal of the copier.
COPYRIGHT© (992 CANON INC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IUPRHIE AU JAPON) 1-9

IGENERAL DESCRIPTION I
V. WARNING INDICATOR AND
REQUIRED ACTION
A. JAM Indicator sV
If an area of this indicator flashes while
copying is taking place, it is likely that the
paper has jammed at the position represent-
ed by the part that is flashing. Check and
take action as follows.
ADF unit document JAM indicator
Copier paper JAM indicator
Right door OPEN indicator
Cassette OUT indicator
Sorter JAM indicator
Figure 1-7
When clearing apaper jam which has
occurred in an option unit (sorter or ADF), refer
to the Service Manual for the option unit.
•ADF unit document JAM indicator
•Copier paper JAM indicator
•Right door OPEN indicator
•Cassette OUT indicator
•Sorter JAM indicator
If paper jams inside the copier, check the
paper pick-up area, separation feeder area,
fixing/copy delivery area, and cartridge area;
and remove all jammed paper.
1
)
Open the front door.
2) Remove the copies from the copy tray.
3) Operate the release and open the copy
delivery assembly.
4) Check if there is copy paper jammed in
the fixing assembly. If there is paper jam
in it, turn the knob of the fixing rollers
clockwise to remove the jammed paper.
5) Close the copy delivery assembly.
6) Check if there is paper jammed in the
separation/feeder area. If there is, swing
the feeder release lever counterclock-
wise to open the feeder, then remove the
jammed paper. Be careful not to tear it.
When removing jammed paper from
the separation area be very careful not to
"tou&theli'pii^eiserisitive drum.
Figure 1-9
7) Open the multifeeder cover, and remove
the paper from the multifeeder tray.
8) Hold the grip found at the bottom of the
multifeeder cover, and open the right
door; then, remove the jam.
Figure 1-10
Figure 1-8
1-10 COPYRIGHT© 1992 CANON INC, CANON NP-1S50 REV.1 SEPT. 199! PRINTED IN JAPAN (IMPRIME AU JAP0N)

IGENERAL DESCRIPTION I
9) Close the right door.
Figure 1-11
10) Close the front door.
B. ADD PAPER Indicator £
1. Cassette
The indicator goes ON when no cassette
is found in the cassette or no paper is found
inside the cassette.
1)Push the center of the cassette.
•The cassette springs out automatically.
Figure 1-12
2) Set copy paper inside the cassette,
rAs many as 250 sheets of copy paper
(80 g/rri) may be set.
Figure 1-13
3) Hold the center of the cassette, and slide
it into the cassette holder until it stops.
2. Multifeeder
The indicator goes ON when the paper
on the multifeeder tray is not positioned
correctly or the multifeeder cover is left
open.
•As many as 50 sheets of copy paper
(80 g/rri) may be set on the
multifeeder tray.
COPYRIGHT© 1992 CANON INC. CANON NP-1550 REM JAN. 1992 PRINTED IN JAPAN (IMPRIMEAUJAPON) 1-11

GENERAL DESCRIPTION
C. ADD TONER Indicator i
This indicator flashes when the amount of
toner in the black developing assembly has
become low.
1. Black developing assembly
1
)
Open the front door.
2) Turn the developing assembly release
lever counterclockwise.
3) Pull the developing assembly forward as
far as possible.
4) Open the top cover of the developing
assembly.
5) Shake the toner cartridge back and forth
about 1times.
6) Place the toner cartridge on the develop-
ing assembly.
7) While holding the toner cartridge in
place, remove the seal slowly to allow
the toner to flow out.
Figure 1-14
8) Tap the top of the toner cartridge to
remove any toner remaining in the car-
tridge.
9) Carefully remove the toner cartridge.
10) Close the top cover of the developing
assembly.
11) Put the developing assembly back into
the copier.
12) Swing the developing assembly release
lever clockwise.
13) Close the front door.
2. CT Unit (color developing unit)
If copy images become faint, the color
toner has probably run out. In this case,
replace the CT unit. The copy image can
sometimes be temporarily restored by
placing the CT unit in its storage box and
agitating it.
Note:
The CT unit is adiscardable type.
When the color toner has been used up,
toner is not added to the CT unit; rather,
the entire unit is replaced.
D. CONTROL CARD
Indicators:
The control card indicator operates on a
copier with acontrol card unit. It flashes in
the following cases.
a) When there is no control card in the
control card unit.
b) When there is acontrol card in the
control card unit but the indication on
the control card unit is "P" or "EE".
1-12 COPYRIGHT© 1992 CANONINC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAP0N)

GENERAL DESCRIPTION!
VI. DAILY INSPECTION
TO BE PERFORMED
BY THE CUSTOMER
Carefully instruct the customer to be sure
to clean the following parts of the copier
once aweek.
1.Primary corona assembly
Slide in and out the wire cleaner to clean
the corona wires.
2. Copyboard glass
Clean the copyboard glass with adamp
cloth, then wipe it dry.
3. Copyboard cover
Clean the copyboard cover with amild
detergent solution, then wipe it dry.
4. Transfer corona assembly
Remove the transfer corona assembly
from the copier, then slide the knob (wire
cleaner) at the bottom of the transfer
corona assembly back and forth to clean
the corona wires.
Further, clean the static eliminator using
the cleaning brush (accessory).
COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.1 SEPT.1992 PRINTED IN JAPAN (IHPRIHE AU JAPON) 1-13

ICOPYING PROCESS I
I. IMAGE FORMATION
PROCESS
A. Outline
Copy board glass
III II II " " rr\
/> i-JS—Scanning lamp
<*r—<*>
iLens
1Developing T*
Primary corona assembly assembly
Pre-exposure lamp~-^^j\
Cleaning roller Drum cleaner..
assemrjiy i
Lower fixing roller
Figure 2-1
This copier consists of the units shown in
Figure 2-1.
The image forming process is divided into
the eight steps shown below.
Step 1:Pre-exposure
Step 2: Primary corona (negative DC)
Step 3: Image exposure
Step 4: Developing (positive plus AC)
Step 5: Transfer (negative DC)
Step 6: Separation
Step 7: Fixing
Step 8: Drum cleaning
Electrostatic latent image formation block
c
(2. Primary corona )**(3. Image exposure j
1.Pre-exposure
(8Drum cleaning )
J
(Copy delivery j
.Fixing ~~j
6. Separatio
(4. Developing )
;J,,
(5. Transfer )CMulti feed ")
njQRegistration )
cCassette w
COPYRIGHT© 1992 CANON INC.
Flow of copy paper
-»— Direction of rotation of drum
Figure 2-2
CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON] 2-1

ICOPYING PROCESS I
The outer surface of the photosensitive
drum is alayer of organic photoconductor
(OPC).The base is an aluminum (conductive)
cylinder.
Photoconductive
layer
Base
C. Step 1Pre-Exposure
r-"-!"^ Pre-exposure lamp
Filter
Figure 2-3 Figure 2-5
B. Electrostatic Latent Image
Formation Block
This stage consists of three steps. At the
end of the stage, the drum has apattern of
negative electrical charges on its surface
corresponding to the dark parts of the
document image. The light areas of the
document image are represented on the
drum by an absence of charges.
The pattern of negative charges cannot
be seen by the eye, hence it is called an
electrostatic latent image.
Time (t) —
/r"\"
/iLight area
-500- //
/
C 3
ffl \
Q
O
ODark area
1000- ^Q. Ep Image exposure
n. g> tk (step 3)
Figure 2-4
Before the primary corona step, light from
the pre-exposure lamps is shone onto the
surface of the drum (pre-exposure). This
process ieliminates residual charges and
helps to make the density of the copy even.
D. Step 2 Primary Corona
Primary corona assembly
Figure 2-6
The primary corona (negative) applies a
uniform layer of negative charges over the
drum surface.
The drum surface potential, is determined
by the grid potential. The grid is connected
to ground through avaristor, which holds the
drum potential constant at the varistor break-
down voltage.
2-2 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON)

E. Step 3Scanning Exposure
Optical image
Light from the original is projected onto
the drum surface. Charges in these light
areas on the drum are neutralized by drum
photosensitive effects.
F. Step 4Developing
Blade
Cylinder
1Developing
Magnet jcylinder
Figure 2-8
ICOPYING PROCESS
Color developer is atwo-component type
consisting of iron powder (carrier) and toner
mixed together in afixed ratio. The main
component of the toner is resin. The toner is
charged to apositive potential and the iron
powder to anegative potential by friction with
the rotating cylinder.
—Blade
/tk_ Concentrated
Vay-magnetic
Magnet
Developer
Figure 2-9
Aconcentrated magnetic field develops
between the magnet and the edge of the
blade. This field attracts the charged
developer.
The developer is held virtually immobile by
the magnetic field, forming acurtain along
the edge of the blade. As the cylinder
rotates, this curtain skims the toner particles
on its surface to athin uniform layer.
An AC bias plus anegative DC bias are
applied simultaneously to the developing
cylinder so that the waveform of the
developing bias has alarger negative
excursion than positive.
Positive
excursion
Negative
excursion
DC bias
Figure 2-10
As shown in Figure 2-8, the developing
assembly consists of adeveloping cylinder (a
stationary magnet surrounded by arotating
sleeve) and ablade made of magnetic
material. Black toner is asingle component
type consisting of afine powder of mixed
magnetite and resin binder. The toner has
insulating properties and is charged to a
positive potential by friction with the rotating
cylinder.
During copying toner is attracted to the
drum by the charges on the drum surface
and by repulsion due to the developing bias
(during the positive excursion), transforming
the latent electrostatic image into avisible
image. Excess toner particles are attracted
back to the cylinder from the drum due to the
charges on the drum surface and the
developing bias (during the negative
excursion).
The DC bias affects copy density and
fogging: As the DC bias becomes less
negative (approaches 0V), the density and
degree of fogging both increase.
COPYRIGHT© 19)2 CANON INC. CANON NW550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIHE AU JAPON) 2-3

ICOPYING PROCESS I
G. Step 5Transfer H. Step 6Separation
Copy paper Copy paper
Transfer corona
assembly
Figure 2-11 Figure 2-12
In this step, anegative corona is applied
to the back of the copy paper, attracting the
toner from the surface of the drum to the
copy paper.
The copy paper is separated from the
drum by utilizing its stiffness. Thin paper,
however; is not stiff, and may wrap around
the drum instead of separating from it. To
prevent this, apositive voltage is applied to
the separation static charge eliminator,
weakening the attraction between the drum
and the copy paper. This enables the paper
to separate easily from the drum.
2-4 COPYRIGHT© 1992 CANON INC. CANON NP-1550 REV.1 SEPT. 1992 PRINTED IN JAPAN (IMPfllME All JAPON;

ICOPYING PROCESS I
I. Step 7Fixing
Cleaning roller
Upper fixing roller
Tungsten-halogen
heater (900W)
Lower fixing roller
Toner
Copy paper
Figure 2-13
In this step, the copy paper is pressed
between two heated rollers to make the toner
image permanent.
To prevent the copy paper from wrapping
around the roller and toner offsetting
(adhesion of toner to the roller and transfer of
the toner to the next copy), the surface of the
upper fixing roller is cleaned with the cleaning
roller.
II. AUXILIARY
PROCESSES
A. Blank Exposure
Blank exposure is the process of shining
light onto is simply the removal of the drum
surface potential in the non-image areas
resulting from REDUCTION copying and
using some cassette sizes (paper sizes). The
light for this is produced by the precondition-
ing lamp and is reflected onto the drum by a
reflector.
In the non-image area on the drum
between successive sheets of copy paper,
the grid bias of the primary corona is reduced
to prevent adhesion of toner. For these;
areas, there is no blank exposure for removal
of the surface charges.
B. Ozone Filter
Acatalytic ozone filter in the exhaust fan
prevents ozone (generated by the coronas)
from escaping to the atmosphere by con-
verting the ozone to oxygen.
J. Step 8Drum Cleaning
Cleaning blade
Paddle
Toner catcher
Figure 2-14
This step prepares the drum surface for
the next copying operation. Any residual
toner scraped off the drum by the cleaning
blade and picked up by the toner catcher. It
is then pushed to the back by the paddle.
COPYRIGHT© 1992 CANON INC CANON NP-1 550 REV.O JAN. 1992 PRINTED IN JAPAN (IMPRIMEAUJAPON) 2-5

OPERATIONS AND TIMING
I. BASIC OPERATION
A. Functions
The copier can be divided into four functional sections: paper pick-up and feed system,
exposure system, image formation system, and control system.
Figure 3-1
COPYRIGHT ©1992 CANON INC. CANON NP-1550 HEV.1 SEPT. 1992 PRINTED IN JAPAN (IMPRIME AU JAPON) 3-1