Image forming apparatus having stopper

An image forming apparatus having an image forming part forming an image on paper, and a housing accommodating the image forming part and having a paper stack part stacking paper discharged from the image forming part, the image forming apparatus comprising:

• an accommodating part formed in an edge of the paper stack part and extending in a paper discharge direction;
• a base plate mounted in the accommodating part to be slidable in the paper discharge direction and a reverse direction opposite to the paper discharge direction;
• a stopper hinge-coupled to the base plate to be tiltable among a stand up position where the stopper blocks paper discharged from the image forming part, a rear folding position where the stopper is folded onto the base plate and is at least partially accommodated in the paper stack part, and a front folding position where the stopper is folded in the paper discharge direction;
• and
• a tilt preventing unit to prevent tilting of the stopper while the stopper is located at the stand up position.