Developing cartridge comprising mechanism for information detection

A developing cartridge comprising:

• a housing including an outer surface, the housing configured to accommodate a developing agent;
• a small-diameter gear including a first engaging portion positioned on at least a portion of a peripheral surface of the small-diameter gear, the small-diameter gear being rotatable about a first axis extending in an axial direction through the outer surface;
• a large-diameter gear positioned farther from the outer surface than the small-diameter gear from the outer surface, the large-diameter gear being rotatable together with the small-diameter gear about the first axis;
• a first gear rotatable from a first position to a second position about a second axis different from the first axis, the first gear comprising:
• a second engaging portion positioned on at least a portion of a peripheral surface of the first gear, the second engaging portion being configured to engage with at least a portion of the first engaging portion;
• and
• at least one protrusion positioned closer to the outer surface than the large-diameter gear is to the outer surface in the axial direction, the protrusion being rotatable together with the first gear, wherein the protrusion is movable from an overlapped position in which the protrusion is overlapped with the large-diameter gear in the axial direction to a non-overlapped position in which the protrusion is not overlapped with the large-diameter gear in the axial direction when the first gear rotates from the first position to the second position;
• and
• a contact surface positioned outside of a rotational locus of the large-diameter gear, the contact surface configured to contact the protrusion and move therewith when the protrusion is in the non-overlapped position.