What are the smallest paper margins I can use?
The Auto Sheet Feed and the Rear Feed print with 0.12 in (3 mm) margins all around. The Front Feed prints with 0.12 in (3 mm) left and right margins and 0.79 in (20 mm) top and bottom margins. The 3800 also supports borderless printing, but only for the Auto Sheet Feed and Rear Feed, and only for specific paper sizes. See here for the list of supported sizes.