Image-Forming Apparatus and Developing Unit

An image-forming apparatus comprising:

• a main casing;
• a conveying unit that conveys a recording medium in a conveying direction;
• a plurality of photosensitive bodies that is juxtaposed in the conveying direction with confronting the conveying unit;
• a plurality of developing units that is detachably mounted on the main casing, each of the developing units being configured to move between a first position where the developing unit is capable of supplying developer to the corresponding photosensitive drum and a second position where the developing unit separates from the corresponding photosensitive drum;
• a cleaning member that is configured to move between a third position where the cleaning member is capable of collecting a waste developer deposited on the conveying unit and a fourth position where the cleaning member separates from the conveying unit;
• a pair of first protrusions that is provided on each of the developing units and protrudes outward from both end portions of each developing unit in an axial direction of the photosensitive bodies, respectively;
• a pair of second protrusions that extends in the axial direction, each of the second protrusions being positioned on each side of the cleaning member in the axial direction, the positions of the second protrusions being fixed relative to the cleaning member, one first protrusion of the pair of first protrusions for each developing unit and one second protrusion of the pair of second protrusions being positioned one side in the axial direction and another first protrusion of the pair of first protrusions for each developing unit and another second protrusion of the pair of second protrusions being positioned another side in the axial direction;
• and
• a pair of translation members that is positioned both sides of the photosensitive bodies and the cleaning member in the axial direction, respectively, and is movable in the conveying direction, one translation member of the pair of translation members being engaged with the one first protrusions and the one second protrusion, another translation member of the pair of translation members being engaged with the another first protrusions and the another second protrusion, the plurality of developing units being configured to move between the first position and the second position by the movement of the pair of translation members and the cleaning member being configured to move between the third position and the fourth position by the movement of the pair of translation members.