Exposure device and image forming apparatus

An image forming apparatus performing image formation by transferring a toner image obtained by developing a static latent image formed on a member to be scanned based on image data onto a recording medium, the image forming apparatus comprising:

• an exposure device comprising a shutter member having a slit, the shutter member being provided between the member to be scanned and a housing of a main device unit that has an optical transmission member, and being freely movable between an open position at which the slit is in opposition to the optical transmission member and a shut position at which the slit is not in opposition to the optical transmission member, a light beam being irradiated through the optical transmission member and the slit to the member to be scanned to form the static latent image,
• wherein in the exposure device, a depressed portion is provided below the slit, an aperture portion of the depressed portion being in opposition to the slit at least in a state where the shutter member is moved to the shut position at which a light path of the light beam is shut,
• wherein lengths of the slit in a moving direction of the shutter member and in a direction perpendicular to the moving direction are shorter than lengths of the aperture portion, and
• wherein a seal member is provided on the slit, a lower surface of the seal member being in contact with an entire circumference of an edge of the aperture portion in a state where the shutter member is moved to the shut position.