A sheet processing apparatus includes: a pair of binding members that respectively have a pair of crimping teeth facing each other, which move between binding positions where a sheet bundle is bound and retreat positions retreated from the binding positions; and a pair of regulating members that are arranged close to the binding members and respectively have a pair of regulating pieces which face each other and move between regulating positions where displacement of the sheet bundle bound by the pair of crimping teeth is regulated and retreat positions retreated from the regulating positions, wherein a separation distance between the pair of regulating pieces at the retreat positions of the regulating pieces is longer than a separation distance between the pair of crimping teeth at the retreat positions of the crimping teeth.

A sheet binding device includes a pressurizing unit that pressurizes a sheet bundle to bind the sheet bundle, a pressurizing section that is disposed in the pressurizing unit and configured to be moved from a waiting position separated from the sheet bundle to a pressurizing position at which the pressurizing section pressurizes the sheet bundle, a drive motor that actuates the pressurizing unit, and a controller that controls the drive motor such that the pressurizing section is engaged with the sheet bundle at a predetermined setting velocity.

A thermoplastic film which exhibits elastic-like behavior along at least one axis when stretched or elongated and then released. The thermoplastic film comprises a plurality of raised rib-like elements extending in a direction perpendicular to a main surface of the thermoplastic film. The thermoplastic film further includes a plurality of web areas positioned about the plurality of raised rib-like elements. The plurality of raised rib-like elements and plurality of web areas are arranged in a complex pattern. The complex pattern provides visual and tactile cues as the films are stretched or elongated. The complex pattern can cause the thermoplastic film to have a complex stretch profile.

A thermoplastic film which exhibits elastic-like behavior along at least one axis when stretched or elongated and then released. The thermoplastic film comprises a plurality of raised rib-like elements extending in a direction perpendicular to a main surface of the thermoplastic film. The thermoplastic film further includes a plurality of web areas positioned about the plurality of raised rib-like elements. The plurality of raised rib-like elements and plurality of web areas are arranged in a complex pattern. The complex pattern provides visual and tactile cues as the films are stretched or elongated. The complex pattern can cause the thermoplastic film to have a complex stretch profile.