Abstract: A sheet separating device includes: a lifting nozzle configured to blow air against an end portion of a sheet bundle placed on a sheet loading portion to lift sheets; a separating nozzle configured to separate the sheets; a lifting-nozzle shutter member configured to open and close the lifting nozzle; a separating-nozzle shutter member configured to open and close the separating nozzle; a lifting-shutter driving mechanism configured to drive the lifting-nozzle shutter member; a separating-shutter driving mechanism configured to drive the separating-nozzle shutter member; and an open/close control unit configured to control the lifting-shutter driving mechanism and the separating-shutter driving mechanism such that the lifting-nozzle shutter member and the separating-nozzle shutter member are opened or closed simultaneously.

Abstract: A sheet feeding device includes: a sheet feeding tray attached to a casing in a manner slidable into and out from the casing and including a stacking plate on which sheets are stacked; a conveying unit configured to convey the sheets in a direction orthogonal to both a sliding direction of the sheet feeding tray and a stacking direction of the sheets; an optional extension unit configured to be removably attached to an upstream side of the stacking plate in a conveying direction, and including an extension plate configured to extend the stacking plate; and a first locking unit configured to be capable of being held in a first lock position where the sheet feeding tray cannot be slide when the optional extension unit is attached while, when the optional extension unit is removed, held in a first unlock position where the sheet feeding tray can be slid.

Abstract: A sheet feeding device includes: a sheet stacking member; an air blowing unit configured to blow air onto the sheet bundle placed on the sheet stacking member to suspend multiple sheets of the sheet bundle; a lifting/lowering unit configured to lift/lower the sheet stacking member; an optical reflection sensor configured to detect a suspended sheet suspended by the air blowing unit; and a control unit configured to control the lifting/lowering unit based on an output value of the optical reflection sensor. The optical reflection sensor is configured to be capable of detecting an area corresponding to multiple sheets in a sheet suspension zone extending between a non-suspended sheet bundle and a conveying member configured to convey an uppermost sheet of the multiple suspended sheets. The non-suspended sheet bundle is made up of sheets not suspended during a period when air is blown by the air blowing unit.