Minolta Di 620 Manual page 55

<Calculation of Original's Skew>
•
The skew is calculated from the main-scan and subscan edge values, as follows.
•
Relation (1) gives the angle of tilt.
•
If the user has set the skew warning mode to ON ("user's choice" setting),
then the copier will output a warning if the detected skew is beyond the
acceptable limit.
L
A
B
Original
(1) Skew = (B-A) / (M-L) = tanθ
M-36
M
θ
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