Oce PlotWave 300 User Manual page 240

Load a media roll (position 1)
Align the roll with the centre of the correct size indicator on the roll holder and release
4.
the handle of the locking mechanism.
Note:
If you use a B1 media size (707 mm) you must align the media roll with the A1 indent.
240 Chapter 6 - Maintain the printing system