Epson DFX-9000 Reference Manual page 26

9. Fit the first few holes in the paper over the sprocket pins as
shown below. Now close the sprocket covers.
10. Slide the left sprocket to remove any slack in the paper. Make
sure the paper is straight and has no wrinkles. Push the
sprocket lock lever back to lock the sprocket in place. After
you lock the left sprocket, it may still move slightly; this is
normal.
sprocket lock lever
26
Paper Handling