The duplex unit, in order to reduce the overall duplex copying time, performs interleaving.
Paper exit from the main machine
Length  | No. of interleaves  | 
|---|---|
Less than 216mm  | 3  | 
216-432 mm  | 2  | 
432-457.2 mm  | 1  | 
1-bin tray exit from the main machine
Length  | No. of interleaves  | 
|---|---|
Less than 216mm  | 2  | 
216-432 mm  | 1  | 
- 3 sheet interleave
1 sheet undersurface -> 2 sheet undersurface -> 3 sheet undersurface -> 1 sheet top surface -> 4 sheet undersurface -> 2 sheet top surface - 2 sheet interleave
1 sheet undersurface -> 2 sheet undersurface -> 1 sheet top surface -> 3 sheet undersurface -> 2 sheet top surface -> 4 sheet undersurface