Medium supply device and image forming apparatus

A medium supply device comprising:

• a stacking unit in which media are stackable in a vertical direction;
• a first regulating unit that is provided on the stacking unit and that regulates positions of side portions of the media in a width direction;
• a supply unit that supplies air to more than one of the media stacked on the stacking unit so that the more than one of the media are raised and separated from each other;
• a transport unit that successively feeds the media that are raised and separated from each other by the supply unit;
• a detection unit that detects conditions of the media that are raised and separated from each other by the supply unit from outside in the width direction;
• a second regulating unit that is attached to an upper section of the stacking unit when the media stacked in the stacking unit are second media and that regulates positions of side portions of the second media in the width direction, the second media having a smaller dimension than first media in the width direction;
• and
• a moving unit that moves the detection unit in a horizontal direction to an area in which the second media are detectable when the second regulating unit is attached,
• wherein the moving unit includes a power unit that allows movement of the detection unit to a position at which the detection unit faces the side portions of the second media, and
• wherein the power unit operates in response to attachment of the second regulating unit so that the detection unit moves to the position at which the detection unit faces the side portions of the second media.