(7) Lens drive shaft
This shaft is to control the optical axis of the lens in zoom copying.
The lens follows on the slide base shaft.
(8) Lens drive wire
The wire is used to drive the lens base and the 4/5 mirror base.
(9) No. 4/5 mirror base
The No. 4/5 mirror is installed to this base. It is moved in zoom
copying in order to fit the distance between the original and the
photoconductor.
(10) Mirror motor
The mirror motor is a stepping motor, and used to move the copy
lamp unit and the No. 2/3 mirror base in order to obtain the rpm
corresponding to each magnification ratio.
(11) Mirror home position sensor (MHPS)
Used to sense the home position of the copy lamp unit. This sensor is
a photo transmission type sensor.
(12) No. 2/3 mirror base
The No. 2/3 mirrors are attached to this base. The mirror base is
scanned by the mirror motor.
(13) Copy lamp unit
This is composed of No. 1 mirror, the thermal fuse, the copy lamp,
the exposure adjustment plate, and the reflector, and is scanned by
the mirror motor.
(14) Thermal fuse
The thermal fuse is closely attached to the reflector in order to
prevent against abnormal temperature rise in the optical system. In
case of abnormal temperature rise, the power for the copy lamp is
turned off.
100V system
200V system
(117°C)
(117°C)
(15) Reflector
Light from the copy lamp is reflected onto the original.
(16) Exposure adjustment plates
Four exposure adjustment plates are attached to the copy lamp unit
to adjust the exposure balance in the front and the rear frame direc-
tion.
(17) Mirror base drive wire
This wire is used to transmit the drive power of the mirror motor to the
copy lamp unit and the No. 2/3 mirror base to scan the mirror base.
(18) Lens drive motor
This is a stepping motor, which is used to move the lens and the No.
4/5 mirror base.
(19) AE sensor
The original density is detected with the intensity of the copy lamp
light reflected from the original. The measurement area is the mirror
base scan area of about 100mm at the center.
The element is a photo diode.
5-2. Basic operations
(Relationship among the original, the lens and the image in each
magnification ratio)
Normal copy: The distance between the surface of original on the
table glass and the lens is made equal to the distance
between the lens and the exposure surface of the
photoconductor to make the original and the image
equal to each other.
Enlargement copy: The lens is nearer to the original when compared
with the normal copy to shorten the distance be-
tween the original surface and the lens.
The No. 4/5 mirror base is positioned further
away from the lens to increase the distance be-
tween the lens and the exposure surface of the
photoconductor.
The distance between the original and the ex-
posure surface of the photoconductor is greater
than that in the normal copy.
Reduction copy: When compared with the normal copy, the lens
comes closer to the photoconductor to increase the
distance between the original and the lens. The
distance between the lens and the exposure sur-
face of the photoconductor is decreased.
The No. 4/5 mirror base is positioned further away
from the lens.
The distance between the original and the exposure
surface of the photoconductor is longer than that in
the normal copy.
5 – 4
