Sheet folding apparatus

Abstract

A buckle ( 3, 4 ) is provided with a position adjustable stopper ( 5, 6 ) for stopping a sheet (P) by coming into collision with the leading edge of the sheet (P) so as to position the sheet in a fold position. In the inlet of the buckle, there are provided a pair of rotary drive folding rollers ( 20 a, 20 b; 20 c, 20 d ) for taking the sheet in the buckle, and a pair of rotary drive folding rollers ( 20 b, 20 c; 20 d, 20 e ) for folding a portion of the sheet deflecting from the buckle. A sheet detector ( 16, 17 ) is arranged in the buckle at a predetermined spacing from the stopper. A control section ( 29 ) outputting a signal for deceleration to a driving source of the roller upon reception of a sheet detection signal from the sheet detector and stopping output of the signal for deceleration after elapse of a predetermined time. After the leading edge of the sheet introduced into the buckle passes through the sheet detector, the rotational speed of the roller is reduced to decrease the conveying speed of the sheet, the leading edge of the sheet collides with the stopper at a sufficiently reduced speed, thereafter, the rotational speed of the roller is gradually increased so that the rotational speed before being reduced is recovered when the next sheet is introduced into the buckle.

1 . A sheet folding apparatus having:
 at least one buckle ( 3 ,  4 ) in which a sheet (P) to be folded is introduced to a length corresponding to a predetermined fold position, said at least one buckle ( 3 ,  4 ) being provided with a position adjustable stopper ( 5 ,  6 ) for stopping the introduced sheet (P) by coming into collision with the leading edge of the sheet (P) so as to position the sheet (P) in said fold position;   a pair of rotating rollers ( 20   a,    20   b;    20   c,    20   d ) arranged near the inlet of said buckle ( 3 ,  4 ) and oppositely to each other for taking the sheet (P) in said buckle ( 3 ,  4 ); and   a pair of rotating rollers ( 20   b,    20   c;    20   d,    20   e ) arranged near the inlet of said buckle ( 3 ,  4 ) and oppositely to each other for folding a portion of the sheet (P) deflecting from said buckle ( 3 ,  4 ), the sheet folding apparatus characterized by   a sheet detector ( 16 ,  17 ) arranged at a predetermined spacing from said stopper ( 5 ,  6 ) of said buckle ( 3 ,  4 ) toward the inlet of said buckle ( 3 ,  4 ) and detecting passage of the sheet (P); and   a control section ( 29 ) outputting a signal for deceleration to a driving source ( 23 ) of said roller ( 20   a  to  20   e ) upon reception of a sheet detection signal from said sheet detector ( 16 ,  17 ) and stopping output of said signal for deceleration after elapse of a predetermined time,   whereby, after the leading edge of the sheet (P) introduced into said buckle ( 3 ,  4 ) passes through said sheet detector ( 16 ,  17 ), the rotational speed of said rollers ( 20   a  to  20   e ) is reduced to decrease the conveying speed of the sheet (P), the leading edge of the sheet (P) comes into collision with said stopper ( 5 ,  6 ) at a sufficiently reduced speed, and thereafter the rotational speed of said roller ( 20   a  to  20   e ) is gradually increased so that the rotational speed before being reduced is recovered when the next sheet (P) is introduced into said buckle ( 3 ,  4 ).   
   
   
       2 . A sheet folding apparatus having:
 at least one buckle ( 3 ,  4 ) in which a sheet (P) to be folded is introduced to a length corresponding to a predetermined fold position, said at least one buckle ( 3 ,  4 ) being provided with a position adjustable stopper ( 5 ,  6 ) for stopping the introduced sheet (P) by coming into collision with the leading edge of the sheet (P) so as to position the sheet (P) in said fold position;   a pair of rotating rollers ( 20   a,    20   b;    20   c,    20   d ) arranged near the inlet of said buckle ( 3 ,  4 ) and oppositely each other for taking the sheet (P) in said buckle ( 3 ,  4 ); and   a pair of rotary drive rollers ( 20   b,    20   c;    20   d,    20   e ) arranged near the inlet of said buckle ( 3 ,  4 ) and oppositely to each other for folding a portion of the sheet (P) deflecting from said buckle ( 3 ,  4 ), the sheet folding apparatus characterized by   a sheet detector ( 30 ) arranged upstream of the pair of rollers ( 20   a,    20   b ) for taking the sheet (P) in the uppermost stream buckle ( 3 ) for detecting passage of the sheet (P);   a rotary encoder ( 31 ) mounted on at least one rotating shaft of said rollers ( 20   a  to  20   e ) arranged near the inlet of said buckle ( 3 ,  4 ) or at least one another rotating shaft rotatable in conjunction with said rotating shaft of said rollers ( 20   a  to  20   e ); and   a control section ( 29 ) starting counting the number of pulses outputted from said rotary encoder ( 31 ) upon reception of a sheet detection signal from said sheet detector ( 30 ) to measure the conveying distance of the sheet (P), outputting a signal for deceleration to a driving source ( 23 ) of said roller ( 20   a  to  20   e ) when the sheet (P) reaches a predetermined position, and stopping output of said signal for deceleration when the sheet (P) reaches the next predetermined position,   whereby, after the leading edge of the sheet (P) passes through said sheet detector ( 30 ), the rotational speed of said roller ( 20   a  to  20   e ) is reduced to decrease the conveying speed of the sheet (P), the leading edge of the sheet (P) comes into collision with said stopper ( 5 ,  6 ) at a sufficiently reduced speed, and, thereafter, the rotational speed of said roller ( 20   a  to  20   e ) is gradually increased so that the rotational speed before being reduced is recovered when the next sheet (P) is introduced into said buckle ( 3 ,  4 ).