Mailbox or sorter bin use sensing system

摘要: In a multi-bin sheet collecting system for reproduction apparatus, in which printed sheets may be directed an array of bins job separation, sorting, and/or user mailboxing, to stack on tray selected bin, the removal from individual is sensed indicate availability those receiving further by integral optical transmitter/receiver unit mounted aperture each bin area overlaid stacked thereon. Each has light transmitting element first beam direction towards another next adjacent direction, and second second, opposite generating electrical empty signal controller unless blocked bin. Where at least some are locked but individually openable therefrom, same units can also that their associated open, not reclosed, or cleared all sheets.