An image forming apparatus having a cleaner for cleaning a surface of a dust-proof glass disposed on a housing of a laser scanning unit for irradiating a photosensitive member with a laser modulated in accordance with image data. The cleaner is supported by a frame of the image forming apparatus body such that the cleaner is movable while keeping in contact with the dust-proof glass and such that the cleaner stays in a stand-by position while keeping out of contact with the dust-proof glass and the housing of the laser scanning unit.
