An image forming apparatus comprising: at least one developing unit including a photoconductor and a developing roller movably installed between a first position to come into contact with the photoconductor and a second position to be spaced apart from the photoconductor; a light scanning unit including a light source and at least one transparent window through which light emitted from the light source is transmitted; a cleaning unit including: at least one cleaning cover movably installed to uncover and cover the transparent window in linkage with movement of the developing roller between the first position and the second position respectively; and a drive device including a drive plate to be rectilinearly reciprocated by a drive source to actuate the developing unit and the cleaning unit in linkage with the operation of the drive plate, the drive plate comprising a protrusion for engaging the developing unit and an actuator nip for engaging the cleaning unit, the protrusion being separated from the developing unit and the actuator nip in contact with the cleaning unit at the first position, and the protrusion in contact with the developing unit and the actuator nip separated from the cleaning unit at the second position. at least one developing unit including a photoconductor and a developing roller movably installed between a first position to come into contact with the photoconductor and a second position to be spaced apart from the photoconductor; a light scanning unit including a light source and at least one transparent window through which light emitted from the light source is transmitted; a cleaning unit including: at least one cleaning cover movably installed to uncover and cover the transparent window in linkage with movement of the developing roller between the first position and the second position respectively; and a drive device including a drive plate to be rectilinearly reciprocated by a drive source to actuate the developing unit and the cleaning unit in linkage with the operation of the drive plate, the drive plate comprising a protrusion for engaging the developing unit and an actuator nip for engaging the cleaning unit, the protrusion being separated from the developing unit and the actuator nip in contact with the cleaning unit at the first position, and the protrusion in contact with the developing unit and the actuator nip separated from the cleaning unit at the second position. at least one cleaning cover movably installed to uncover and cover the transparent window in linkage with movement of the developing roller between the first position and the second position respectively; and a drive device including a drive plate to be rectilinearly reciprocated by a drive source to actuate the developing unit and the cleaning unit in linkage with the operation of the drive plate, the drive plate comprising a protrusion for engaging the developing unit and an actuator nip for engaging the cleaning unit, the protrusion being separated from the developing unit and the actuator nip in contact with the cleaning unit at the first position, and the protrusion in contact with the developing unit and the actuator nip separated from the cleaning unit at the second position.