Image forming apparatus

An image forming apparatus comprising:

• a discharge rollers pair configured to discharge and switch back a sheet at a discharge port;
• a sheet pressing member configured to press an upper face of the sheet discharged by the discharge rollers pair;
• and
• a discharge tray on which the sheet discharged through the discharge port is stacked,
• wherein the sheet pressing member includes:
• a first rotational shaft supported above the discharge port along a width direction perpendicular to a discharge direction;
• a detection piece protruding in a radial direction from the first rotational shaft and supported in an initial posture where the detection piece protrudes toward the discharge tray across the discharge port, the detection piece being turnable into a first posture where the detection piece is pushed up by the sheet discharged at a predetermined discharge angle and then turned at a first angle with respect to the initial state and into a second posture where the detection piece is pushed up by the sheet switched back at a predetermined inversion angle and then turned at a second angle different from the first angle with respect to the initial state;
• and
• a corrugation piece protruding in a radial direction different from a protruding direction of the detection piece from the first rotational shaft, rotatable together with the detection piece and configured to come into contact with the discharged sheet from an upper side to apply stiffness to the sheet,
• wherein when the detection piece is turned at the first posture, the corrugation piece is changed into a contact posture where the corrugation piece comes into contact with the sheet to apply stiffness on the sheet, and
• when the detection piece is turned at the second posture, the corrugation piece is changed into a retracting posture where the corrugation piece separates from the sheet.