Ricoh Beluga-C1 Training page 171

LPH Replacement and Adjustment
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Slide 171
LPH REPLACEMENT AND ADJUSTMENT
Adjusting the SP Settings, continued
The three LED heads are not in a straight line across the page.
See the top diagram - the difference between the two at left and right is
exaggerated, but we need to point out that the heads at left and right are
also not exactly lined up.
Because of this, the main scan signals for each head have to be timed so that
they are output in the correct locations on the drum.
If the timing is incorrect, main scan lines will appear to be disjointed at one third
and two thirds of the way across the page, as shown in the lower diagram.
If the values on the decals on the LPH are input into the SP modes as explained
in the manual, this problem should not appear.
These SPs adjust the timing of the main scan lines for each head. The head
that is positioned furthest 'up the page' will print its part of the line first.
Then, as the drum rotates, the other heads will add their segments of the
same scan line, at the correct time.
So, the data being output at a particular instant from the LPH to the drum is
not a continuous scan line, but segments of three different scan lines. But
the output on the page is one continuous line, if the SP settings are correct.
LPH 2
LPH 1
171
Beluga-C1/C1.5 Training
SP 2952 011 and 012
LPH 3