Image forming apparatus and separation device for toner collection

An image forming apparatus comprising:

• an image forming section that forms an image with toner;
• a housing that houses the image forming section;
• and
• a toner collection mechanism that includes
• a suction unit that sucks the toner along with air, the toner leaving the image forming section and flying, and
• a separation unit that separates the toner from air, the toner being sucked by the suction unit, the separation unit of the toner collection mechanism including
• a separator that collects the toner and allows air to pass through the separator,
• a casing that houses the separator and has an upper side and an opening that has an edge and a lower portion, the toner and air flowing through the opening, and
• a joining unit that is disposed along the edge of the opening and joins the casing and the housing to each other,
• wherein the joining unit projects beyond the edge of the opening at least in the lower portion of the opening toward the upper side of the casing, thereby forming a space that allows the toner to be trapped in the space.