Sheet discharge apparatus and image forming apparatus

A sheet discharge apparatus comprising:

• a housing including an upper surface portion and a discharge opening through which a sheet discharged in a sheet discharge direction passes, the upper surface portion including a first surface that is inclined upward while extending downstream in the sheet discharge direction and a second surface that is provided downstream of the first surface in the sheet discharge direction, the first surface and the second surface being configured to receive the sheet discharged from the discharge opening, an angle between the second surface and a horizontal plane being smaller than an angle between the first surface and the horizontal plane;
• a first extension tray including a third surface, disposed at the upper surface portion, and configured to move between a first retracted position and a first use position;
• a second extension tray including a fourth surface and an interlocking portion, disposed at the upper surface portion, and configured to be pivoted between a second retracted position and a second use position, the interlocking portion being configured to move the first extension tray from the first retracted position to the first use position when the second extension tray is pivoted from the second retracted position to the second use position;
• and
• a discharge roller configured to discharge the sheet through the discharge opening and convey the sheet to a position where the sheet comes into contact with the third surface and the fourth surface in a state in which the first extension tray is at the first use position and the second extension tray is at the second use position, wherein
• in a state in which the first extension tray is at the first use position, at least a part of the third surface is positioned downstream of the first surface in the sheet discharge direction, is positioned above the second surface, and is inclined upward while extending downstream in the sheet discharge direction,
• in a state in which the second extension tray is at the second use position, at least a part of the fourth surface is positioned downstream of the third surface in the sheet discharge direction, is positioned above the second surface and the third surface, and is inclined upward while extending downstream in the sheet discharge direction, and
• at least a part of the third surface moves upward when the first extension tray moves from the first retracted position to the first use position.