Patent ID: 7850298

Claim:
An image forming apparatus comprising: a discharge tray, on which a sheet discharged from a discharge port is stacked; a sheet retainer, which guides the sheet discharged from the discharge port onto the discharge tray, and which is displaced in abutment against an uppermost sheet stacked on the discharge tray, the sheet retainer removing electricity of the sheet; and a detection unit, which comprises a photo-sensor, and which detects a stack of the sheet on the discharge tray on a basis of a position of the sheet retainer, wherein the sheet retainer comprises: a shaft member; extensions, which are disposed integrally on the shaft member, which extend from the shaft member, and which contact the sheet; and a shielding plate, which is disposed at one end portion of the shaft member, and which turns in accordance with the extensions to open or shield the photo-sensor wherein each of the extensions comprises a single rigid piece, which is formed of a conductive material, which is configured to remove electricity from the sheet, and which has a stiffness, so that the single rigid piece is not deformed by a pressure received from the sheet.