Ricoh C226 Service Manual page 112

(1) Standard Generation
Pulse
(2) Detecting Pulse
(3) Output of the main
board
(LED 102)
(1) The standard pulse is output from OUTPUT 1. The pulse length (T
be adjusted by adjusting VR901.
(2) OUTPUT 2 is the detection pulse. The time constant is determined by
C908 and the ink. The detection pulse is triggered by the rising edge of
the standard pulse.
When ink is present, the electrostatic capacity increases and the pulse
length (T ) becomes longer. On the other hand, when ink is not present,
1
the pulse length (T
decreases.
(3) The pulse length (T
When the time constant (T
(T ), the output to the main board goes low.
0
SM
) becomes shorter as the electrostatic capacity
2
or T ) is compared with the standard pulse (T
1 2
= No ink) is shorter than the standard pulse
2
2-63
DRUM SECTION
) can
0
).
0
C226