Sheet separating device, sheet supplying device, and image forming apparatus

A sheet separating device comprising:

• 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 driving mechanism configured to drive the lifting-nozzle shutter member- and the separating-nozzle shutter member;
• a suction conveying unit configured to suck the sheets one sheet by one sheet from the sheet bundle placed on the sheet loading portion and convey the sucked sheet using a belt;
• an air suction unit configured to suck air from the suction conveying unit;
• a side air nozzle configured to blow side air against a side surface of the sheet bundle placed on the sheet loading portion;
• a side air blowing unit configured to deliver air to the side air nozzle;
• a lifting blowing unit arranged at the lifting nozzle and configured to blow air through the lifting nozzle;
• and
• a separating blowing unit arranged at the separating nozzle and configured to blow air through the separating nozzle;
• and
• a controller configured to,
• control the driving mechanism such that the lifting-nozzle shutter member and the separating-nozzle shutter member are opened or closed simultaneously,
• adjust a suction rate of the air suction unit, a blowing rate of the side air blowing unit, a blowing rate of the lifting blowing unit, and a blowing rate of the separating blowing unit, and
• set the suction rate of the air suction unit and the blowing rates of the side air blowing unit, the lifting blowing unit, and the separating blowing unit in accordance with a plurality of preset modes.