EPSON AcuLaser C1900/AcuLaser C900 Revision B
Operating Principles Description of Mechanisms 115
2.4.8  Other Mechanisms
2.4.8.1  Duplex Unit (option)
DRIVE
The Duplex Unit is driven as follows: the paper after printing on one side is fed into the 
paper eject tray once and when the tail end of the paper has left the guide behind the paper 
eject roller, the paper eject roller starts rotating to transport the paper into the Duplex Unit.
With the Duplex Unit installed, the paper eject roller is separated from the drive on the 
printer body and is driven by the paper eject motor in the Duplex Unit.
The transport roller in the Duplex Unit is driven by the transport motor in the Duplex Unit.
The paper is transported into the printer body by the transport roller.
Figure 2-30. Mechanism of Duplex Unit
PAPER LOAD METHOD
Note: Steps 2 to 6 above are repeated for the subsequent sheets of paper.
Duplex Unit Inversion Motor (M8)
両面ユニット搬送モータ (M7)
Transport Roller
Duplex Unit Transport Motor (M7)
Duplex Unit Transport Sensor (PC17)
Table 2-13. 1-sheet Circulation Method
Function
1. A sheet of paper is loaded and the image of the 2nd 
page is printed.
2. The sheet is fed to the paper eject tray once and 
immediately before the sheet leaves the paper eject 
roller, the paper eject roller changes the direction of 
rotation.
3. The sheet of paper is transported into the Duplex Unit.
4. The sheet in the Duplex Unit stops once at the refeed 
position.
5. The image of the 1st page is printed on the sheet refed 
from the Duplex Unit.
6. The sheet of paper is ejected.
2
2
2
1 2