A toner cartridge includes a photoconductive drum and a boss that protrudes outward from a first longitudinal end of the toner cartridge at a rotational axis of the photoconductive drum. An outermost axial segment of the boss along the rotational axis includes a partial cylinder having a cross-sectional shape of a circular segment. An outer circumferential surface of the partial cylinder is convex to a bottom of the toner cartridge and forms a bottom contact surface of the boss that is unobstructed to contact and sit in a corresponding V-block in an image forming device when the toner cartridge is installed in the image forming device. The outermost axial segment of the boss includes clearance above a topmost portion of the partial cylinder and within the radius of the outer circumferential surface of the partial cylinder permitting the clearance to accommodate one or more features in the image forming device.