Sheet folding device with conveying roller capable of partially rotating around folding roller

A sheet folding device comprising:

• a folding path;
• a positioning member to support a leading edge of a sheet fed along the folding path and to align the sheet at an initial folding position;
• a first folding roller;
• a second folding roller, the first folding roller to engage with the second folding roller to form a folding nip;
• a folding blade to move to an insertion position to push the sheet on the folding path into the folding nip;
• a guide path provided around the first folding roller to return the sheet that has passed through the folding nip to the folding path;
• a guide member which forms the guide path between an outer periphery of the first folding roller and the guide member, the guide member being rotatable around the first folding roller;
• and
• a conveying roller that is rotatably located on the guide member and is to engage with the first folding roller to form a conveying nip and is to feed the sheet along the guide path.