Roland GR-540 User Manual page 357

Slide the material to place its left edge over the grit roller.
At this point, check that the right edge of the material remains over the grit roller on the right edge.
Straighten the material.
Align the right edge of the material so that it is parallel to the gradations of the rulers (in two
locations: one on the top and one on the bottom).
*: Ruler gradation
2: Right edge of the material
1: Grit roller
2: Left edge of the material