Reverse feeding device

A reverse feeding apparatus for switching back and feeding a sheet, comprising:

• feeding roller means for feeding a sheet in a first direction from an upstream path to a downstream path;
• reverse feeding roller means for feeding a sheet in a second direction that is different from the first direction;
• at least one branch nail movably mounted adjacent the feeding roller means;
• at least one guiding nail movably mounted adjacent the feeding roller means, wherein a tip of the branch nail and a tip of the guiding nail are positionable to overlap the feeding roller means when the sheet is not being fed in the first direction by the feeding roller means,
• branch nail pressing means for pressing the branch nail to the position overlapping the feeding roller means to increase friction between a sheet being fed in the first direction and the feeding roller means;
• and
• guiding nail pressing means for pressing the guiding nail to the position overlapping the feeding roller means to permit a front end of a sheet being fed in the second direction to pass by a lower face of the guiding nail,
• wherein the pressure applied by said guiding nail pressing means is smaller than the pressure applied by said branch nail pressing means.

A method for switching back and feeding a sheet, comprising the steps of:

• using at least one feeding roller to feed a sheet in a first direction from an upstream path to a downstream path;
• using a reverse feeding roller located at the downstream path to feed the sheet in a second direction that is different from the first direction;
• using at least one branch nail movably mounted adjacent the feeding roller to press the paper sheet being fed in the first direction toward the at least one feeding roller;
• and
• using at least one guiding nail movably mounted adjacent the feeding roller to guide the sheet being fed in the second direction without obstructing the inertial movement of the sheet in the first direction.