The present disclosure provides a process cartridge and a potential detection part. The process cartridge includes a cartridge body, a photosensitive drum rotatably installed at the cartridge body, and a potential detection part configured to detect an electrical signal on the image-forming region. The potential detection part includes a detection starting portion and a detection ending portion; the detection starting portion and the detection ending portion respectively correspond to a detection starting position and a detection ending position of a detectable region of the potential detection part along a first direction; a maximum distance along the first direction between orthographic projections of the detection starting portion and the detection ending portion on the image-forming region is L1; a length of the image-forming region along the first direction is L2; the first direction is in parallel with an axis direction of the photosensitive drum; and L1/L2>.

A developing device includes a development container, a first conveyance member, a second conveyance member, a developer carrier, and a toner concentration sensor. The first conveyance member and the second conveyance member are rotatably supported in the development container, and convey the developer, while stirring the developer, in mutually opposite directions along a longitudinal direction of the development container. The first conveyance member includes a rotation shaft and a first conveyance blade helically formed on an outer circumferential part of the rotation shaft. The first conveyance blade includes a cutout portion formed by removing part of the first conveyance blade in a facing region with respect to the toner concentration sensor.