SHEET PUNCHING APPARATUS FOR FORMING A PUNCHING HOLE IN AN EXACT POSITION OF A PAPER AND A DRIVING METHOD THEREOF

摘要

PURPOSE: A sheet punching apparatus and a driving method therefore are provided to detect position of end portions of paper and state of attachment or detachment of the punching apparatus using only two sensors, thereby forming a punching hole in an exact position of the paper. CONSTITUTION: A punch unit(120) moves in a direction perpendicular to moving direction of a paper. A bracket(122) has an elastic element(12) and is movable with the punch unit. A paper lateral end portion-detecting element(S10) is fixed at the bracket and detects a lateral end portion of the paper according to motion of the bracket. A paper back end portion-detecting element(S20) is opened so as to detect a back end portion of the paper when the paper lateral end portion-detecting element moves. The punch unit performs punching at a predetermined position of the paper, after the detections of the lateral end portion and the back end portion of the paper.