Aligning unit and image forming apparatus

An image forming apparatus, comprising:

• an apparatus main body for applying an image forming process to a transfer material, and
• an aligning unit for aligning transfer materials after the image formation, wherein the aligning unit includes:
• a tray having a placing surface on which sheet-like transfer materials discharged with printing applied thereto are held stacked;
• a dent provided in the tray and formed below the placing surface;
• a first restricting member movable back and forth along an advancing direction of the transfer material being discharged onto the tray while facing the front end of the transfer material with respect to the advancing direction;
• a second restricting member for defining the rear end position of the transfer material with respect to the advancing direction,
• the transfer materials stacked on the tray being aligned by the first restricting member being moved back and forth along the advancing direction, and the first restricting member including a base end portion located below the placing surface and movable back and forth along the advancing direction in response to a driving force, a standing wall extending upward from the base end portion and having a contact surface extending substantially vertically above the placing surface of the tray, and an inclined surface extending from the contact surface toward the placing surface and inclined downward along a direction opposite to the advancing direction, and
• the dent extends along the advancing direction, the base end portion is moved back and forth in a state that the base end portion is accommodated in the dent, and the bottom end of the inclined surface moved back and forth below the placing surface along the extending direction of the dent.