Original Size Sensing - Ricoh FT7770 Service Manual

4. Original Size Sensing

- Sensing Mechanism -
The original size sensor board holds
(one registration
Sensor No.
SN1 or 2
SN3 or 4
SN5
SN6
None
The board is powered by +12 volts from CN105-A2. CN105-B4 is ground, so
the LEDs are always on.
on the photosensors that it passes under.
+12 volts to the DF main board input pins.
A pulse generator is mounted on the shaft of the lower relay roller, which
rotates due to friction.
thus measuring the length of the original. Then the CPU determines the orig-
inal size by comparing the size sensor data and the length data.
sensor and four size sensors).
Original Size
A4(L), A4(S), A5(S), 8½
13" 8½", 13"
X
A3, B4, 15"
11" x 17"
A5(L), 5½"
When an original is fed to the belt unit, it turns
The CPU monitors pulses from the pulse generator,
of five reflective photosensors
an array
X
8"
X
11", 14"
X X
8½", 8½" 11"(L), 10½"
X X
The activated photosensors apply
7-27
30
11"(S)
10", 8½" 14"
X
8"
X
April, '89