HP 510 - Manual (Page 146)

What is rotated?
With roll paper, both the image and the page orientation are rotated.
Notice that the narrow margins are always at the left and right sides, regardless of the orientation. The page size
is adjusted to maintain the printing area, preventing clipping.
With sheet paper, the image is rotated, but the page orientation specified in your software is retained. (You should
always load sheet paper in the orientation you have specified in the software.)
0 º 90 º
A
A
0 º 90 º
A A