Sheet folding apparatus

Abstract

Buckles (b 1 to b 4 ) are each provided with a stopper (S 1 to S 4 ). A pair of uptake rollers (W, W 1 ); (W, W 2 ); (W 2, W 3 ); (W 3, W 4 ), to supply paper to the buckles, and a pair of discharge rollers (W, W 2 ); (W 2, W 3 ); (W 3; W 4 ); (W 4, W 5 ), to fold the portion of the paper discharged outside the buckles, are disposed at each buckle inlet. The discharge roller for a previous buckle simultaneously functions as the uptake roller for the next buckle, and the paper is sequentially introduced into the buckles and folded into a bellows form. Stopper drive mechanisms (d 1 to d 4 ) are integrally controlled by a control unit (C). The control unit receives input for the value of the difference in length between the last folded piece and the remaining folded piece of a bellows-folded paper in which a folding error has occurred, divides the length difference by the number of buckles, and sends control instructions to slide the stoppers in the same direction as the buckle inlet (e) relative to the stopper drive mechanisms for the length obtained by division in order to make the length difference zero.

1 . A sheet folding apparatus which folds up a sheet like an accordion by alternating mountain and valley folds of the sheet in a direction perpendicular to a sheet feed direction, the sheet folding apparatus comprising:
 a sheet supply unit sequentially feeding the sheet from a sheet stack; and   a sheet folding unit folding the sheet fed from the sheet supply unit in the direction perpendicular to the sheet feed direction,   the sheet supply unit comprising:   a shelf on which the sheet stack is placed;   a conveyor belt extending between the shelf and the sheet folding unit; and   a sheet feeder feeding the sheet from the sheet stack to the conveyor belt one by one,   the sheet folding unit comprising:   a plurality of buckles into which the sheet fed from the conveyor belt is inserted sequentially; and   a stopper attached to each of the buckles so as to be slidable along the sheet feed direction, wherein, each time the sheet is inserted into the buckles, the sheet is positioned at a preset folding position by colliding with the associated stopper at the leading end thereof,   the sheet folding unit further comprising:   a stopper drive mechanism arranged at each of the buckles so as to move the associated stopper;   a pair of driven intake rollers arranged in the neighborhood of an inlet of each of the buckles and opposed to each other so as to take the sheet in the associated buckle; and   a pair of driven discharge rollers arranged in the neighborhood of the inlet of each of the buckles and opposed to each other so as to fold a portion of the sheet exteriorly protruding from the associated buckle, the discharge roller associated with a previous buckle concurrently serving as the intake roller associated with the next buckle, thereby the sheet being sequentially inserted into the buckles so as to be folded at the number of times corresponding to the number of the buckles, characterized in that   the sheet folding apparatus further comprises a control unit integrally controlling the stopper drive mechanisms of the sheet folding unit, and   the control unit receives an input of a difference in length between the last flap and the remaining flaps of an accordion-folded sheet accompanied with a folding error and divides the difference in length by the number of the buckles, wherein   when the last flap is longer than the remaining flaps, in order to eliminate the difference in length, the control unit sends control signals to each of the stopper drive mechanisms in such a way that the associated stopper is moved in a direction away from the inlet of the associated buckle by the distance corresponding to the result of the division, and when the last flap is shorter than the remaining flaps, in order to eliminate the difference in length, the control unit sends control signals to each of the stopper drive mechanisms in such a way that the associated stopper is moved in a direction toward the inlet of the associated buckle by the distance corresponding to the result of the division.