Binding processing device

A binding processing device comprising:

• a first pressing member that includes a convex portion protruding toward a sheet bundle in which a plurality of sheets are stacked;
• and
• a second pressing member that includes a concave portion configured to be combined with the convex portion through the sheet bundle to form a gap between the convex portion and the concave portion, the second pressing member configured to press the sheet bundle sandwiched between the first pressing member and the second pressing member, wherein
• with the sheet bundle being sandwiched between the convex portion and the concave portion, the first pressing member and the second pressing member partially rupture fibers constituting the sheet bundle in the gap to form a ruptured section where the fibers are loosened, and press the ruptured section to cause the ruptured fibers to be press-bonded to each other, so as to bind the sheet bundle.

A binding processing device comprising:

• a first pressing member provided by an alternate arrangement of a plurality of first convex portions and a plurality of first concave portions, the first convex portions each being formed by a curved surface protruding toward a sheet bundle, the first concave portions each being formed by a curved surface recessed in a direction away from the sheet bundle;
• and
• a second pressing member provided by an alternate arrangement of a plurality of second concave portions and a plurality of second convex portions, the second pressing member configured to press the sheet bundle sandwiched between the first pressing member and the second pressing member, the second concave portions each being formed by a curved surface to be combined with the counterpart first convex portion through a first gap and opposite to the counterpart first convex portion through the sheet bundle, the second convex portions each being formed by a curved surface to be combined with the counterpart first concave portion through a second gap and opposite to the counterpart first concave portion through the sheet bundle, wherein
• a volume of the first gap is larger than a volume of the sheet bundle to be sandwiched between each of the first convex portions and the counterpart second concave portion, and
• a volume of the second gap is larger than a volume of the sheet bundle to be sandwiched between each of the second convex portions and the counterpart first concave portion.