US Patent 11042105 Developing cartridge including housing and gear

In a cartridge, a developing roller is configured to rotate around a first rotational axis extending in a predetermined direction and to carry developer thereon, the developing roller having a first end and a second end apart from each other in the predetermined direction, a from-first-to-second direction being defined along the predetermined direction as being directed from the first end to the second end. A developing electrode is formed of a conductive material and is configured to be electrically connected to the developing roller, the developing electrode including a main part and a protruding portion protruding from the main part in the from-first-to-second direction. A detection body is formed of an insulating material and is rotatably supported by the protruding portion, the detection body including a first opening that exposes part of the protruding portion and a covering portion covering part of the protruding portion.