Sheet Material Accumulating Method And Sheet Material Accumulating Apparatus

Abstract

Provided are a sheet material accumulating method and a sheet material accumulating apparatus capable of performing a proper accumulation of a sheet material that does not produce a defective in the next process even when an overlap condition of a conveyed sheet material, such as a printed sheet, varies. Provided is a sheet material accumulating method for accumulating the sheet material W continuously conveyed from the above while a part of the sheet material W is overlapped, with the sheet material standing on a lower horizontal table 7, including the steps of: detecting a backpressure F that a bundle of sheet materials applied to a holder 8 for preventing a head side collapse of a bundle of sheet materials accumulated on the table during an accumulation process; and controlling a movement of the holder in an accumulation direction so that a backpressure may maintain a predetermined magnitude.

1 . A sheet material accumulating method for accumulating a sheet material continuously conveyed from the above while a part of the sheet material is overlapped, with the sheet material standing on a lower horizontal table, comprising the steps of:
 detecting a backpressure from a bundle applied to a holder for preventing a head side collapse of the bundle of the sheet materials accumulated on the table; and   controlling a movement of the holder in an accumulation direction so that the backpressure may maintain a predetermined magnitude.   
   
   
       2 . The sheet material accumulating method according to  claim 1 , wherein
 detection of the backpressure from the bundle is performed by detecting a load current to an electric motor for moving the holder, and   the control of the movement of the holder is performed by controlling an applied current to the electric motor.   
   
   
       3 . A sheet material accumulating method for accumulating a sheet material continuously conveyed from the above while a part of the sheet material is overlapped, with the sheet material standing on a lower horizontal table, wherein
 in a process of retreating a bundle of sheet materials in order to accumulate afresh the sheet material after the bundle of sheet materials has grown to a predetermined size,   a head side of the bundle to be retreated is supported by the a first holder and a back end side of the bundle is supported by a second holder,   a backpressure from the bundle applied to the first holder and a backpressure applied from the bundle to the second holder are detected, and   movements of the first holder and the second holder in an accumulation direction are controlled so that the respective backpressures may maintain respective predetermined magnitudes.   
   
   
       4 . The sheet material accumulating method according to  claim 3 , wherein
 detection of the respective backpressures is performed by detecting the load currents to the respective electric motors for retreating the first holder and the second holder, and   control of movements to retreat the first holder and the second holder is performed by controlling applied currents to the respective electric motors.   
   
   
       5 . A sheet material accumulating apparatus for accumulating a sheet material continuously conveyed from the above while a part of the sheet material is overlapped, with the sheet material standing on a lower horizontal table, comprising:
 a holder for preventing a head side collapse of a bundle of sheet materials accumulated on the table;   backpressure detecting means adapted to detect a backpressure from the bundle applied to the holder;   holder moving means adapted to make the holder move in an accumulation direction of the sheet material; and   control means adapted to control an operation of the holder moving means; wherein   the control means is configured to control a movement of the holder caused by the holder moving means based on a backpressure detected by the backpressure detecting means.   
   
   
       6 . The sheet material accumulating apparatus according to  claim 5 , wherein
 the holder moving means has an electric motor,   the backpressure detecting means has a load current detecting device of the electric motor, and   the control means is configured to control a movement of the holder caused by the electric motor based on a load current detected by the load current detecting device.   
   
   
       7 . The sheet material accumulating apparatus according to  claim 6 , wherein
 the electric motor is a servomotor, and   the control means is configured to control an applied current to the servomotor based on the load current detected by the load current detecting device.   
   
   
       8 . A sheet material accumulating apparatus for accumulating a sheet material continuously conveyed from the above while a part of the sheet material is overlapped, with the sheet material standing on a lower horizontal table, comprising:
 a first holder for preventing a head side collapse of a bundle of sheet materials accumulated on the table;   a second holder for supporting a back end side of the bundle;   backpressure detecting means adapted to detect one or both of a backpressure from the bundle applied to the first holder and a backpressure applied therefrom to the second holder;   first holder moving means adapted to make the first holder move in an accumulation direction of the sheet material;   second holder moving means adapted to make the second holder move in the accumulation direction of the sheet material; and   control means adapted to control one or both of operations of the first holder moving means and the second holder moving means; wherein   the control means is configured to control one or both of movements of the first holder and the second holder by the first holder moving means and the second holder moving means based on a backpressure detected by the backpressure detecting means.   
   
   
       9 . The sheet material accumulating apparatus according to  claim 8 , wherein
 the first holder moving means and the second holder moving means each have an electric motor,   the backpressure detecting means has a load current detecting device of the each electric motor, and   the control means is configured to control movements of the first holder and the second holder caused by the electric motor based on the respective load currents detected by the load current detecting devices.