Sheet feeder, has stack receptacle carrying sheet stack, and suction head vertically adjustable by adjusting unit, which is controlled by signals of sensor, where upper stack front edge of stack is scanned by sensor

摘要

The feeder has a stack receptacle (1) carrying a sheet stack (12). An upper stack front edge (18) of the sheet stack is scanned by a sensor (16) i.e. optical sensor. A sucker (19) overlaps the stack. An upper stack rear edge (11) of the stack is scanned by another sensor i.e. presser foot (10). The stack is adjustably controlled in a vertical direction based on signals emitted by the former sensor and on signals emitted by the latter sensor. A suction head is vertically adjustable by an adjusting unit, which is controlled by the signals of the former sensor.