You may find that the edges of some designs are clipped and do not print. This is because most printers leave about a quarter-inch of white space around the edges of each page.
There is nothing T-Shirt Factory can do about this: It's a hardware limitation of the printer.
Consult your printer's user guide to determine what its margins are. Most inkjet printers have a larger margin at the bottom of the page, usually about a half inch.
Adjust your design so that it doesn't bleed into your printer's margins. This will prevent any clipping of the design.
If you're using an Epson inkjet printer, open the File menu and choose Page Setup. Locate the Printable Area radio button and change it from Standard to Maximum. This allows printing up to an eighth of an inch from the edge of the page.