4-36
FS-1900
The paper size dial has predetermined patterns of activating the paper size switches using concaves
and convexes according to paper sizes. SW1, SW2, and SW3 produce corresponding signals for
paper sizes. These patterns are translated into analog voltages and sent to the engine board on a
single line. The signals are analog-digital-converted on the engine board.
Figure 4-3-14 Paper size detecting circuit
Off
Off
Off
0 V
Off
Off
On
1.94 V
Off
On
Off
1.19 V
Off
On
On
1.58 V
Custom
LegalLetter
On
Off
Off
0.42 V
A4
On
Off
On
2.28 V
A5
On
On
Off
2.92 V
B5
On
On
On
3.22 V
Cassette
not
installed
See
note
below.
Paper size switch
Note: Toner install mode cancellaton signal (See page 3-14)
SW1
SW2
SW3
Convex
(Function On)
Concave
(Function Off)
Paper size
Paper size dial
D/A converted
output voltage
GND
+24V1
Engine board
Sensor board
Paper size switch
SW2
SW3
SW1
CPU
(U204)
GND GND
Paper cassette
Paper size dial
R701
R238
C246
R702
R703
R704
DZ70
Approximately
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