Ricoh DD5450 Field Service Manual page 163

1. LED Display and Output Signal on the Ink Detection PCB Unit
● When the electric capacity variation between the detection needles on the ink detection PCB Unit
and GND is over the threshold value, the LED on the ink detection PCB Unit lights up and the ink
signal (0V) is output.
● Timing of the LED and the ink pump motor operation is as follows.
The ink pump motor works only during printing (driving output signal).
2. "NO INK" Display Timing
When HIGH (5V) is output by detecting ink while the drum continues to rotate 20 times (the number
of rotations varies depending on the printing speed.*) during printing, it is detected that the ink pack
is empty, "NO INK" is displayed on the error display, and printing stops.
At the same time the power for the ink pump motor is turned off.
* The drum rotates until "NO INK" is displayed on the LCD panel after HIGH (5V) is output from the
ink detection PCB unit while printing. The number of drum rotations varies depending on printing
speed as shown in the table below.
Print speed 1
Number of drum
20
rotations
2 3 4 5
20 20 30 30
Chapter 3
Ink detection PCB unit
LED
No ink Light out
Ink supplied Light up
6: High-speed print speed
30
Drum Section
7
CN1-2
+5V
0V
３
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