Image forming apparatus

An image forming apparatus comprising:

• a duct configured to guide air outside the image forming apparatus to a cooling target;
• and
• a fan configured to generate an airflow for taking air outside the image forming apparatus into the duct, wherein
• the duct includes:
• a first flow passage;
• a second flow passage bent from the first flow passage and extending in a first direction, the second flow passage being provided with an outlet of the duct;
• and
• a plurality of flow dividing plates provided in the second flow passage, the plurality of flow dividing plates being disposed in parallel along a second direction orthogonal to the first direction and forming a third flow passage between the flow dividing plates adjacent to each other, and
• when a length in the first direction of the third flow passage is L (mm) and a length in the second direction of the third flow passage is D (mm), the L satisfies following conditions:
• if 3.0≤D≤5.5,L≥D×3.04−6.72;
• if 5.5≤D≤6.5,L≥D×4.0−12.0;
• if 6.5≤D≤9.0,L≥D×8.40−40.60;
• if 9.0≤D≤13.0,L≥D×10.50−59.50;
• and
• if 13.0≤D≤28.0,L≥D×4.70+15.90.