Image forming apparatus having a filter that covers an opening portion

An image forming apparatus comprising:

• an image forming portion configured to form a toner image on a recording material;
• a fixing portion configured to form a nip portion to nip the recording material, and configured to fix the toner image to the recording material by heating the toner image while conveying the recording material;
• a housing which accommodates the image forming portion and the fixing portion and in which a conveyance path that the recording material passes through is formed;
• and
• a discharge portion configured to discharge the recording material in a discharge direction intersecting with a vertical direction to an outside of the housing,
• wherein the housing includes a first exterior surface and a second exterior surface, the first exterior surface facing in the discharge direction and being provided with a discharge port that the recording material discharged by the discharge portion passes through, the second exterior surface facing in a direction opposite to the discharge direction and being provided with an opening portion through which the outside of the housing and an inside of the housing communicate with each other,
• wherein at least part of the discharge port and at least part of the opening portion are positioned above an upper end position of the nip portion in the vertical direction,
• wherein the image forming apparatus further comprises a filter disposed to cover the opening portion,
• wherein in a width direction orthogonal to both the vertical direction and the discharge direction, a center of the conveyance path is positioned between one end and an other end of a range where the opening portion is provided,
• wherein the housing includes an exterior member having the second exterior surface and an inner surface provided on an opposite side to the second exterior surface, and an opposing portion opposing the inner surface of the exterior member with a gap therebetween,
• wherein a space continuous with the gap and the outside of the housing communicate with each other through the opening portion,
• wherein the exterior member has a rib protruding in a direction from the inner surface toward the opposing portion and extending in a direction intersecting with the width direction,
• wherein the filter is attached to the inner surface at a position different from the rib in the width direction, and
• wherein in a range where the filter is provided in the vertical direction, a thickness of the filter is smaller than a protruding amount of the rib with respect to the inner surface.