Patent ID: 7883088

Claim:
Apparatus for singling sheet material, comprising: an input area having a width and configured to receive stacks of sheet material to be singled; a singler arranged to single sheet material received in the input area; a stack transport arrangement upstream of the singler enabling transport of stacks of sheet material from the input area to the singler in a stack transport direction; a sheet transport system; said singler arranged to feed singled sheets of sheet material to the sheet transport system; said sheet transport system arranged to receive singled sheets of sheet material from the singler and to transport them from the singler in a sheet transport direction; a sensor disposed upstream of the singler relative to the stack transport direction, said sensor arranged to sense an area extending over the width of the input area, and to generate signals which specify whether and in which area of the width of the input area the sheet material is present, and a control device, arranged to receive and evaluate the signals of the sensor during a transport of the stack of sheet material to the singler and to compare fluctuations and changes of the signals of the sensor regarding the presence or absence of sheet material with predetermined threshold values for fluctuations and changes of the signals of the sensor, and to derive information from the fluctuations and changes of the signals of the sensor as to whether the sheets forming the stack of sheet material are aligned with each other with respect to their edges, and whether the stack of sheet material has an alignment which substantially is parallel to the sheet transport direction; wherein the control device is arranged to control the singler so as to prevent the singling of the stack of sheet material when an evaluation of the signals of the sensor indicates that the sheets of sheet material forming the stack of sheet material are poorly aligned with each other with respect to their edges or the stack of sheet material has an alignment which deviates from the sheet transport direction.