Ricoh D129 Service Manual page 652

System SP Tables-4
Dust Detect: Lvl
Adjusts the sensitivity for dust detection on the ADF scanning glass. This SP
is available only after SP4020-1 is switched on.
[0 to 8 / 4 / 1]
If you see black streaks in copies when no warning has been issued, raise
002
the setting to increase the level of sensitivity. If warnings are issued when
you see not black streaks in copies, lower the setting.

Dust Reject: Lvl
Selects the level of the sub scan line correction when using the ARDF.
003
[0 to 4 / 0 / 1]
0: OFF, 1: Weakest, 2: Weak, 3: Strong, 4: Strongest
APS Operation Check
4301
Displays a code that represents the original size detected by the original
sensors. (
APS Min. Size
Determines whether an original of non-standard size is detected as A5/HLT
size by the APS sensor.
4303
0: No original
1: A5 - lengthwise (SEF)
2: A5 - Sideways (LEF)
If "0" is selected, "Cannot detect original size" will be displayed.
D129/D130
Dust that triggers a warning could move be removed from the glass
by the originals in the feed path. If the dust is removed by passing
originals, this is not detected and the warning remains on.
p.3-251 "Input Check")
3-48 SM Appendix