Loop/Second Paper Feed Control - Minolta Di850 Service Manual

[3] Loop/Second Paper Feed Control

M12
MC1
PS1
PS44
PS45
The paper fed from one of trays 1-3 is fed to the second
paper feed unit. The second paper feed takes place as
the result of the transmission of the drive force from
M12 (registration) to the second paper feed roller via
MC1 (registration MC). The second paper feed unit is
preceded by the loop roller, and this conveyance unit is
also used for the paper fed from the ADU or LCT
excluding the paper from the bypass tray. The loop
roller is driven by M6 (loop roller).
The above parts are controlled by the PRCB (printer
control board) via he PRCB (DC drive board) and
ADUSDB (ADU stand drive board).
Related signals are PS44 (registration), PS45 (leading
edge detection), and PS54 (loop detection). When the
front right or left door of this machine opens or closes,
MS1 (interlock 1) or MS2 (interlock 2) operates to inter-
rupt the DC power supply to the motors, stopping M6
and M12.
1. Operation
a. Loop control
The paper fed from each tray is fed to the second
paper feed roller by the loop roller. When PS44 is
turned ON, the paper is decelerated and stopped
temporarily to form a loop. After a lapse of spec-
ified time, MC1 is turned ON to transmit the drive
24VDC
M12 CONT
M12 CLK
M12 EM
PGND
24VDC
MC1 CONT
24VDC
5VDC
-5VDC
PS1 VIDEO
PS1 SI
PS1 CLK
5VDC
PS1 LED
SGND
SGND
5VDC
PS44
24VDC
SGND
PGND
PS45
ADUSDB
b.
c.
2-N-9
5VDC
PS54
SGND
24VDC
24VDC
M6 DRIVE A
M6 DRIVE A
M6 DRIVE B
M6 DRIVE B
PRCB
DCPS1
DCPS2
force of M12 to the second paper feed roller, thus
feeding the paper to the transfer/separation sec-
tion. When the second paper feed starts, the loop
roller feeds the paper at the low linear velocity
which is the same as that of the second paper
feed roller.
Second paper feed control
After formation of a loop is completed, MC1 is
turned ON to transmit the drive force of M12 to
the second paper feed roller, starting the second
paper feed.
Mis-centering detection control
Mis-centering of the paper fed from each tray is
detected by PS1 (paper mis-centering) and it is
corrected at the time of image write.
A contact sensor is used as PS1. The paper
edge position is detected by mis-centering sen-
sors. Based on the edge position information, the
image write position is shifted to correct mis-
centering. PS1 operates in the specified interval
after PS45 is turned ON.
ADU
PS54
M6