Epson Stylus Pro 7450 User Manual page 202

When attaching roll paper with a 3-inch core, slide the gray
attachments to the black and white ones, matching the four
arrows.
3. Place the roll paper on a flat surface so that it does not unwind.
Slide the roll paper onto the spindle and onto the white flange
until it fixes into place.
Note:
Do not stand the spindle when attaching the roll paper. It may cause
slant paper feeding.
4. Slide the black movable flange (removed in step 1) onto the
spindle and into the end of the roll paper until it fixes into
place.
Paper Handling
202