Ricoh PRIPORT VT 2000 Series Service Manual page 230

3.1.6 Focus Adjustment (MTF Adjustment)
Test Chart R-21
B
B
x 100 ≥ 48%
•
A
•
Amplitude "B" (difference between white and black levels) must be a
maximum
Purpose: To focus the lens (focus distance between the CCD and the lens).
1. Position the test chart so that the 8 lines/mm section on the test chart can
be read.
2. Press the Print Start key to turn on the fluorescent lamp.
3. Confirm that the wave form is similar to the above illustration.
4. If incorrect, loosen the allen screw [A] and adjust the lens position [B] by
moving it as shown by the arrow.
5. After adjustment, retighten the allen screw.
8 lines/mm
[B]
5-17
28 February '91
[A]
A