Minolta Di551 Service Manual page 46

Platen APS read position
PS61
Home position search
(2) When the START button is ON
L1 (exposure lamp) turns ON. Next, M11 (scan-
ner) moves the exposure unit toward the paper
exit side. After being driven by the specified num-
ber of steps, M11 (scanner) stops, thus reading
the light reflected by the white reference plate
installed underneath the glass stopper plate and
performing the first white correction. Next, M11
moves the exposure unit toward the paper exit
side. After being driven by the specified number
of steps, M11 performs the second white correc-
tion.
Then, M11 proceeds to the ADF copy operation
or platen copy operation.
First white correction
Second white correction
Black correction
2-C-3
e. ADF copy operation
After completion of the shading correction
started by pressing the START button, M11
(scanner) moves the exposure unit toward the
paper exit side. After being driven by the speci-
fied number of steps from the position where
PS61 (scanner HP) was turned ON, it stops. This
position is the exposure position for ADF copy
operation.
Then, ADF copy operation is performed. After
completion of the ADF copy operation, L1 (expo-
sure lamp) is turned OFF to start searching for
the exposure unit home position.
PS61
Platen APS read position
Home position search
Original read position
SCANNER SECTION
First white correction
Second white correction