Minolta Di551 Service Manual page 109

ADU
*6 Non-stack paper feed mechanism
In the two-sided copy mode, the ADU reverse
roller starts rotating in the opposite direction
when the reverse/exit PS (PS46) detects the
trailing edge of paper and consequently it turns
OFF. The paper is fed toward the reverse/exit
section. However, since the ADU gate is closed,
the paper is fed to the ADU conveyance roller/1
through the path above this gate. Thus, the paper
is reversed and fed to the ADU exit, without being
stacked in the ADU.
The reversed paper is fed by ADU conveyance
rollers 1-4.
3
1 2
8 7
1. Reverse/exit roller
2. ADU conveyance roller/1
3. ADU conveyance roller/2
4. ADU conveyance roller/3
5. ADU conveyance roller/4
6. ADU pre-registration roller
7. ADU reverse roller
8. Reverse/exit PS (PS46)
*7 ADU pre-registration mechanism
In the ADU, paper is looped by the ADU pre-reg-
istration roller to correct paper inclination in the
conveyance section. The ADU pre-registration
roller stops when the loop roller motor (M6)
stops; however, the ADU conveyance roller con-
tinues to feed paper at a constant speed, forming
a paper loop between the ADU pre-registration
roller and ADU conveyance roller. As a result,
paper inclination is corrected. When M6 starts,
the ADU pre-registration roller starts rotating to
feed the paper to the second feed section. An
ADU conveyance MC (MC13) is provided to turn
4 5
6
2-N-6
ON/OFF the drive force of ADU conveyance roll-
ers 1 and 2 in order to stop the looped paper tem-
porarily and to adjust the loop size. In addition,
an ADU deceleration MC (MC2) is provided to
turn ON/OFF the drive force of ADU conveyance
rollers 3 and 4. The ADU conveyance MC
(MC13) is turned ON/OFF only when the paper
length is 325 mm or longer. If the paper length is
less than 325 mm, it stays ON during copying.
1
1. ADU conveyance roller/3
2. ADU conveyance roller/4
3. ADU pre-registration roller
4. Pre-registration loop formation point
*8 Thick paper conveyance mechanism
To enhance reliability of thick paper copying, the
conveyance motor (M5), paper exit motor (M7),
reverse/exit motor (M8), and ADU reverse motor
(M9) are switched as shown below according to
the paper type selected in the key operator
mode.
Paper type
185 mm/s
Thick paper
Others
2
3
4
Linear speed
280 mm/s 55-cpm
320 mm/s 65-cpm