Loop/Second Paper Feed Control - Minolta Di551 Service Manual

[3] Loop/Second Paper Feed Control

The paper fed from each tray is fed to the second
paper feed section. The second paper feed takes
place as the result of the transmission of the
drive force from M5 (conveyance) to the second
paper feed roller via MC1 (registration). The sec-
ond paper feed section is preceded by a loop
roller used to form a paper loop, and this convey-
ance section is also used for the paper fed from
the LCT. It is not used for the paper fed from the
by-pass tray or ADU. The loop roller is driven by
M6 (loop roller). The above parts are controlled
by PRCB (printer control board) via ADUDB
(ADU drive board). M6 is driven by PRCB
directly.
Related signals are PS36 (loop), PS43 (leading
edge), PS44 (registration), and PS50 (ADU pre-
registration).
24V
24V
A
/A
B
/B
5V3
LOOP PS
S.GND
IO DTXD
IO DCLK
ADU LATCH
IO UCLK
REQ1
IO URXD
ACK1
ERR OUT1
2NDM CLK
REG PS
PRCB
5V2
24V1
S.GND
24V1
5V2
S.GND
P.GND
-5V1
DCPS
1. Operation
a.
b.
c.
2-N-7
M6
PS36
+5V
PGND
START/STOP
CLK
M5
CW/CCW
LD
H/L
PGND
+24V
MC24V
MC1
2ND MC
5V2
PS43
EDGE PS
S.GND
5V2
PS44
2ND PS
S.GND
5V2
PS50
ADUEXT PS
S.GND
DEF VIDEO
GMD
5V2
-5V
PS70
GND
DEF SI
DEF CLK
DEF LED
24V1
ADUDB
Loop control
After a lapse of the specified time from turning
ON of PS44 (registration) by the paper fed from
each tray or the ADU at a high speed, M6 (loop
roller) is turned OFF to form a paper loop in the
registration section.
Second paper feed control
After formation of a paper loop under loop con-
trol, MC1 (registration) is turned ON to transmit
the drive force of M5 (conveyance) to the second
paper feed roller, starting the second paper feed.
Image position correction control
Mis-centering of the paper fed from each tray is
detected by PS70 (paper mis-centering) and the
paper leading edge timing is detected by PS43
(leading edge) and they are corrected at the time
of image write.
ADU