Developing cartridge including shaft and cam positioned on opposite side of casing from developing roller and movable in axial direction of developing roller

A developing cartridge comprising:

• a casing configured to store developing agent;
• a developing roller rotatable about a first axis extending in a first direction and having a peripheral surface, a part of the peripheral surface on one side in a second direction being exposed to an outside of the casing and another part of the peripheral surface on an other side in the second direction being positioned inside the casing, the developing roller being positioned at one end portion of the casing in a third direction crossing both the first direction and the second direction;
• a cam shaft extending along a second axis extending in the first direction, the cam shaft being movable in the first direction relative to both the casing and the developing roller;
• and
• a first cam positioned at one end portion of the cam shaft in the first direction and movable in the first direction together with the cam shaft, the first cam having a first inclined surface that is inclined to approach the developing roller in the second direction as extending toward the one end portion of the cam shaft from an other end portion of the cam shaft in the first direction,
• wherein a dimension of the casing in the third direction is smaller than a dimension of the casing in a fourth direction orthogonal to both the first direction and the third direction, and
• wherein the cam shaft and the first cam are positioned at an other end portion of the casing in the third direction.