Abstract: An image printing apparatus has an upper main body provided with a drum, electrifying apparatus and lightexposure apparatus therein and a lower main body is provided with image-transferring apparatus and a developing apparatus having a developer carrier roller. The upper main body is pivotally detachable from the lower main body. The image printing apparatus is further provided with a protecting cover having a semi-cylindrical body section whose outer surface is formed with a plurality of semicircular protrusions. The protecting cover encloses the upper part of a developer carrier roller of the developing apparatus when the upper main body is detached from the lower main body, so that the protecting cover can prevent foreign matter from entering into the developer carrier roller. Also, the semicircular protrusions facilitate the guidance of the printing paper.