Sheet folding device and sheet post-processing apparatus including the same

A sheet folding device comprising:

• a folding rollers pair including a first roller and a second roller brought into pressure contact with the first roller, the folding rollers pair configured to cause a sheet conveyed along a sheet conveyance path extending in a first conveyance direction to pass through a first nip area between the first roller and the second roller to fold the sheet in two and to convey the sheet in a first direction crossing to the first conveyance direction;
• a folding blade that extends in an axial direction of the folding rollers pair, is disposed facing the folding rollers pair, and is selectivity disposed in a folding position where the folding blade pushes a folded portion into the first nip area to perform a folding processing and in a retracting position where the folding blade is retracted from the folding position;
• a movable guide that extends in the axial direction on an upstream side of the folding rollers pair in the first direction, and can reciprocate between a covering position covering an outer circumferential surface of the second roller disposed on a downstream side of the first roller in the first conveyance direction and the first nip area and a non-covering position exposing the outer circumferential surface of the second roller and the first nip area;
• and
• a drive mechanism which shifts the folding blade in the folding position and in the retracting position, wherein
• the drive mechanism includes;
• a drive source which drives the folding blade;
• and
• a link member coupling the folding blade with the movable guide, wherein
• the drive mechanism disposes the folding blade in the folding position while disposing the movable guide in the non-covering position via the link member, and disposes the folding blade in the retracting position while disposing the movable guide in the covering position via the link member.