The present technology relates generally to devices and methods for preserving the integrity of folders that are placed into ringed binders or notebooks, preferably folders that are made of paper or other like material, and which are used for example for the transport and storage of papers by students or other types of users.

A binding tool for paper sheets includes: a base member extending in a longitudinal direction; and a plurality of first binding members and second binding members each having a base end portion formed protruding outward in a width direction from the base member and a tip end portion integral with the base end portion and curved inward in the width direction so as to be movable between a binding position where the tip end portions contact each other and an open position where the tip end portions are separated from each other by a prescribed distance. The base end portions are positionally displaced from each other by at least an amount corresponding to a thickness TH of the base end portion in the longitudinal direction when the tip end portions positioned facing each other in the width direction are in contact with each other in the binding position.

A sheet punching apparatus includes a waste box formed of insulating resin, a detection sensor provided in the waste box and configured to detect the amount of paper chips in the waste box, and a conductive member disposed such that at least a part thereof is positioned in midair in the waste box below the detection sensor. With this configuration, erroneous detection of the detection sensor can be prevented.