Ricoh PRIPORT VT 2000 Series Service Manual page 227

28 February '91
3.1.3 Shading Adjustment
Purpose: To flatten the white level waveform. This also, corrects for distortion
to the light intensity due to the output characteristics at both lamp
ends and aberrations within the lens section.
1. Close the scanner unit [A].
2. Press the Print Start key to turn on the fluorescent lamp.
3. Confirm that the above white level waveform is displayed.
4. If incorrect, move the shading plate [B] position vertically (up or down), so
that the waveform is similar to the one above.
5. After adjustment, retighten the mounting screws [C] of the shading plate
[B].
[C]
[A]
The middle of the wavefrom
should be higher than the ends.
Up
Down
B ≥ 0.6A
5-14
[B]
A
B