Sheet tray, conveyance unit and image recording apparatus

A sheet tray, comprising:

• a first tray including a first sheet support surface;
• a second tray including a second sheet support surface and configured to be movable between a first position and a second position in a first direction, the first position being a position at which at least a part of the second sheet support surface, which is positioned below the first sheet support surface, overlaps with the first sheet support surface, the second position being a position which is located further in the first direction than the first position, and an overlapping area of the first sheet support surface and the second sheet support surface that is located in the second position being smaller than an overlapping area of the first sheet support surface and the second sheet support surface that is located in the first position;
• and
• a third tray pivotally supported by the second tray and configured to pivot between a first pivoting position and a second pivoting position, the first pivoting position being a position in which a pivoting front end of the third tray is positioned on an upstream side of a pivoting shaft of the third tray in the first direction, the second pivoting position being a position in which the pivoting front end is positioned on a downstream side of the pivoting shaft in the first direction to extend beyond the second tray in the first direction, the third tray including a third sheet support surface in cooperation with the second sheet support surface with the third tray being in the first pivoting position and a fourth sheet support surface being a back surface of the third sheet support surface and in cooperation with the second sheet support surface with the third tray being in the second pivoting position, the third sheet support surface further including a protrusion which protrudes upward to be positioned above the second sheet support surface in a state that the third tray is in the first pivoting position, the protrusion including an inner space which is accessible from an outside of the sheet tray.