Patent ID: 8509676

Claim:
A perforation device, comprising: a plurality of punches which punch holes on a sheet by a reciprocation motion; a holding member which holds the punches in a line in a width direction of the sheet; a plurality of dies being arranged opposing to the plurality of the punches; a drive shaft to be rotary driven by a driving device; two cranks being arranged with phases of an angle being displaced with each other in a shaft rotating direction of the drive shaft, to rotate together with the drive shaft; and two connection poles connecting with the two cranks and the holding member, wherein the two cranks are rotatable to reciprocate the holding member with phases at ends thereof being displaced in order to carry out a differential perforation of cut-outs with a time difference among perforations by each of the punches; wherein the reciprocation of the holding member continues in both directions at least until each of the punches reaches a perforation position where the punches perforate the sheet; and wherein holding positions of predetermined punches, among the punches held by the holding member, are displaced in a reciprocation direction with respect to the holding member, and wherein a lower most position which each of the punches reaches at differential perforation falls within a predetermined range.