Stack scanner for paper sheets on feeder table - contains optical reflex and capacitive sensors for optimal table height control and detection of last sheet

摘要

An arrangement for sensing a stack of sheets on the stacking table of a sheet feeder contains a reflex light sensor mounted above the stack with its optical axis coaxial with a bore through the table. The reflex sensor and a capacitive sensor are mounted immediately above the top edge of the stack. The capacitive sensor generates signals corresp. to the distance between the top edge of the stack and the sensor. The signals are used to control the table height. The table is lowered to min. height when the reflex sensor beam passes into the table bore. USE/ADVANTAGE - Enables optimal control of table height and reliable detection of last sheet being used or folded.