Patent attributes
An exposure device is provided with a shutter member having a slit. The shutter member is provided between a member to be scanned and a housing of a main device unit that has an optical transmission member. The shutter member is 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, and a light beam is irradiated through the optical transmission member and the slit to the member to be scanned. Furthermore, in the exposure device, a depressed portion is provided below the slit, and an aperture portion of the depressed portion is 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.