Minolta Di551 Service Manual page 107

ADU
*3 Second paper feed auxiliary mechanism
The distance between the registration roller and
the transfer and separation corona unit is made
long to achieve the time required for correcting
the image position. To assist conveyance of
paper between the registration roller and the
image transfer and separation corona unit, a pre-
transfer roller is provided just before the transfer
and separation corona unit.
5
4
1. Leading edge PS (PS43) (rear)
2. Paper mis-centering PS (PS70) (front)
3. Registration roller
4. Pre-transfer roller
5. Transfer and separation corona unit
*4 Conveyance section paper suction mecha-
nism
A paper suction duct is provided in the middle of
the conveyance section and is led to the convey-
ance suction fan (FM3) installed in the ADU. To
improve transportability of the paper that passes
through the conveyance section, the conveyance
suction fan is used to provide suction for the
paper.
2
1
1. Conveyance section
2. Suction holes
3. Conveyance suction fan (FM3)
4. Duct
1
2
3
3
4
2-N-4
*5 Reverse/exit paper path selection
The reverse/exit selection gate in the fixing unit
determines whether the paper is to be ejected
straight or reversed and ejected. The paper gate
is operated by the reverse gate SD (SD7)
installed in the ADU.
Because paper is reversed in the reverse/exit
section in the ADU, the reverse/exit section is
provided with a reverse/exit gate to switch
between the forward and backward paper con-
veyance paths. This gate has no drive mecha-
nism and it is opened by the rigidity of the paper.
a. Reverse/exit operation
Normally, the reverse/exit selection gate opens
when the reverse gate SD (SD7) is turned OFF.
The paper fed by the exit roller in the fixing unit is
fed, through the path under the reverse/exit
selection gate, to the reverse/exit section in the
ADU by the decurler
reverse/exit gate in the reverse/exit section is
closed. This gate is opened by the rigidity of the
fed paper, allowing the paper to be fed to the
reverse/exit roller, ADU gate, and ADU reverse
roller sequentially. Normally, the ADU gate is
closed and it has no drive mechanism; it is
opened by the rigidity of paper.
When the paper reverse PS (PS42) detects the
trailing edge of paper and consequently turns
OFF, the reverse/exit roller and ADU reverse
roller start rotating in the opposite direction, feed-
ing the paper back toward the fixing unit. How-
ever, since the reverse/exit gate is closed, the
paper is fed to the main body exit roller via the
path outside this gate. Thus, the paper is ejected
with the print side down.
roller. Normally, the