Method and device for ejecting defective sheets at a feeder of a processing machine and feeder having the ejecting device

Abstract

A method and a device for ejecting a defective sheet at a feeder of a processing machine, in particular a sheet-fed rotary printing machine, include a transporting device, which can be regulated independently of machine operation, for transporting a sheet identified as a defective sheet with deceleration in such a way that gripper devices of a cylinder cannot grip the sheet and the sheet is transported to a depositing location by the transporting device and a guide. A feeder of a sheet-fed rotary printing machine having an ejecting device, is also provided.

1 . A method for ejecting a defective sheet, the method comprising the following steps:
 providing a processing machine with a feeder at which the defective sheet is to be ejected, a sensor for sensing defective sheets, a cylinder, gripper devices, and a transporting station for feeding a sheet to the cylinder; and   transporting a sheet identified as a defective sheet through the transporting station with deceleration and transporting the sheet further without the defective sheet being received by the gripper devices.   
     
     
         2 . The method according to  claim 1 , wherein the processing machine is a printing machine. 
     
     
         3 . The method according to  claim 1 , which further comprises transporting the defective sheet with the transporting station to a depositing location. 
     
     
         4 . The method according to  claim 3 , which further comprises transporting the defective sheet to the depositing location with transporting rollers to be driven in opposite directions. 
     
     
         5 . The method according to  claim 1 , which further comprises disengaging all blanket cylinders of the processing machine at discrete points in time one after the other in accordance with an intended arrival of the sheet in a respective nip between a blanket cylinder and an impression cylinder. 
     
     
         6 . In a processing machine having a feeder, a cylinder and a machine drive, a device for ejecting a defective sheet at the feeder, the device comprising:
 a transporting station for feeding sheets to the cylinder, said transporting station having a drive to be regulated in time with the processing machine, but independently of the machine drive.   
     
     
         7 . The device according to  claim 6 , wherein said transporting station has at least one transporting belt. 
     
     
         8 . The device according to  claim 6 , which further comprises a sensor for sensing a defective sheet, and a control computer connected to said drive and interacting with said sensor. 
     
     
         9 . The device according to  claim 6 , which further comprises an ejecting device disposed downstream of said transporting station. 
     
     
         10 . The device according to  claim 9 , wherein said ejecting device includes a directing device with a curved directing plate disposed in a stationary manner. 
     
     
         11 . The device according to  claim 10 , wherein said directing plate is disposed beneath a feed cylinder and above a feed plane intersected by said directing plate. 
     
     
         12 . The device according to  claim 10 , which further comprises a depositing location for sheets disposed downstream of said directing plate. 
     
     
         13 . The device according to  claim 11 , which further comprises two interacting transporting rollers to be driven in opposite directions, said transporting rollers being disposed in an ejecting path formed by said directing plate and said plane. 
     
     
         14 . A feeder of a sheet-fed rotary printing machine, said feeder comprising an ejecting device according to  claim 6 .