Sheet transport device, image reading device, and image forming apparatus

A sheet transport device comprising:

• a sheet load tray on which a sheet is loaded;
• a side-edge positioning unit that comes into contact with a side edge of the sheet in a direction intersecting a sheet transport direction of the sheet loaded on the sheet load tray at an upper surface of the sheet load tray and that positions the side edge of the sheet to a normal position;
• and
• a regulating unit that is provided in a rotatable manner about a rotation shaft at a lower surface of the sheet load tray and that regulates an output position of the sheet by rotating a stopper of the regulating unit to a position where the stopper is capable of colliding with a downstream edge of the sheet to be output in an output direction when the side-edge positioning unit moves to a position corresponding to a minimum width of the sheet,
• wherein when the side-edge positioning unit is located at a position other than the position corresponding to the minimum width of the sheet, the stopper of the regulating unit rotates to a position where the stopper does not collide with the downstream edge of the sheet to be output in the output direction, so as to be accommodated at the lower surface of the sheet load tray.

A sheet transport device comprising:

• a sheet load tray on which a sheet is loaded;
• a pair of side-edge positioning units that come into contact with side edges of the sheet in a direction intersecting a sheet transport direction of the sheet loaded on the sheet load tray at an upper surface of the sheet load tray and that position the side edges of the sheet to normal positions;
• and
• a regulating unit that is provided in a movable manner in a sheet output direction at a lower surface of the sheet load tray and that regulates an output position of the sheet by moving a stopper of the regulating unit upstream in the output direction to a position where the stopper is capable of colliding with a downstream edge of the sheet to be output in the output direction when the side-edge positioning units move to positions corresponding to a minimum width of the sheet.