Developing cartridge provided with delayed transmission mechanism capable of distributing load applied to motor

A developing cartridge comprising:

• a casing;
• a developer container provided in the casing, the developer container being configured to be sealed to accommodate developer;
• a developing roller rotatably supported to the casing and having a rotation shaft;
• an unsealing mechanism rotatably supported to the casing and having a rotation shaft, the unsealing mechanism being configured to unseal the developer container;
• a first rotary body provided at one end portion of the rotation shaft of the unsealing mechanism;
• a second rotary body, a drive force generated by a drive source being transmitted to the first rotary body and the second rotary body, the second rotary body being configured to transmit the drive force from the drive source to the rotation shaft of the developing roller;
• and
• a delayed transmission mechanism delaying transmission of the drive force from the drive source to the second rotary body for at least a prescribed time after transmission of the drive force from the drive source to the first rotary body is initiated, the prescribed time being equivalent to a time that elapses from a moment the unsealing mechanism begins rotating to a moment the unsealing mechanism has unsealed the developer container.