Minolta Di551 Service Manual page 47

SCANNER SECTION
f. Platen copy operation
Platen copy operation is performed in different
ways depending on whether AE control is per-
formed.
After completion of the shading correction
started by pressing the START button, AE scan-
ning is performed in the paper feed direction if the
AE mode has been selected.
Then, exposure scanning is performed at the
speed corresponding to the specified magnifica-
tion by the distance corresponding to the original
size, thus searching for the home position.
(1) Operation with AE
PS61
Platen APS read position
Home position search
(2) Operation without AE
Platen APS read position
PS61
Exposure scanning
Home position search
First white correction
Second white correction
AE scanning
Exposure scanning
First white correction
Second white correction
2. Signals
a. Input signals
(1) SIG/SCANHP_PS (PS61 to SCDB to PRCB)
Scanner home position detection signal
The reference position of the home position of
the exposure unit is detected.
[L]: The exposure unit is detected.
[H]: The exposure unit is not detected.
b. PRCB output signal
(1) SCAN_CLK (PRCB to SCDB)
M11 (scanner) clock signal
(2) SCAN_F/R (PRCB to SCDB)
M11 (scanner) rotational direction switchover
signal
[L]: The exposure unit is moved toward the paper
exit side.
[H]: The exposure unit is moved toward the paper
feed side.
(3) MODE1 to 3 (PRCB to SCDB)
M11 (scanner) energize switchover signals
(4) SCAN_CUR1 to 3 (PRCB to SCDB)
M11 (scanner) energize current switchover sig-
nals
c. SCDB output signals
(1) U, V, W (SCDB to M11)
M11 (scanner) drive control signals
These signals are used to control rotation of M11
(scanner). By supplying and stopping clock
pulses, the motor is turned ON/OFF and the rota-
tional direction is switched.
2-C-4