Blade and post-processing apparatus

(canceled)

(canceled)

A saddle folding method for saddle-folding a sheet, comprising:

• pushing a blade comprising a protrusion portion that protrudes in a pushing direction of the blade on an edge of a folding side of the sheet between a pair of folding rollers, wherein the blade comprises a plurality of protrusions aligned in a thickness direction of the blade, and the plurality of protrusions engage the folding side of the sheet when pushing the blade;
• and
• pushing the blade comprising protrusions closer together toward a center side in the thickness direction when viewed from a direction orthogonal to a pushing direction and the thickness direction.

(canceled)

(canceled)

A blade for a saddle folding unit that facilitates saddle-folding a sheet, the blade comprising:

• a protrusion portion that protrudes in a pushing direction of the blade on an edge of a folding side of the sheet in the blade,
• wherein the protrusion portion comprises a plurality of protrusions aligned in a thickness direction of the blade, and
• wherein the protrusions protrude in the pushing direction, the protrusions being closer together toward one side in the thickness direction when viewed from a direction orthogonal to the pushing direction and the thickness direction.