Patent ID: 7400842

Claim:
An image forming apparatus, comprising: a plurality of imaging units, each of which includes an image carrier and a developing device, the imaging units detachably arranged in a main unit of the image forming apparatus; an optical writing device configured to scan respective light beams emitted from a light source toward respective image carriers, and to perform optical writing on the image carriers; a heat exhaust duct provided for each of the imaging units and arranged between the optical writing device and each of the imaging units; and an exhaust fan arranged on a side opposite to a side from which the imaging units are attached or detached to and from the main unit, and configured to cause air heated at the imaging units to be exhausted outside the main unit via the heat exhaust ducts, wherein a cross-sectional shape of the heat exhaust duct in a direction normal to the image carrier is set such that a length thereof in a horizontal direction is larger than a length thereof in a vertical direction.