Adjusting The Focus (Mtf Adjustment) - Ricoh VT3500 Service Manual

1 December 1993

3.3 ADJUSTING THE FOCUS (MTF ADJUSTMENT)

RESOLUTION
CHART 200DPI
Purpose: To adjust the focus distance between the CCD and the lens.
Ajustment Standard: a−b
1. Position the resolution chart so that the 200 dpi area on the test chart can
be read.
2. Press the Print Start key to turn on the fluorescent lamp.
3. Check if the waveform looks like the one you see in the illustration above.
4. If it does not, loosen the Allen screw [A] and adjust the position of the
lens [B] by moving it as shown by the arrow.
5. After the adjustment, retighten the Allen screw [A].
a−b
a+b
b
a
[A]
[B]
x 100 ≥ 60 %
a+b
5-12
x 100 ≥ 60%