Developing cartridge, processing cartridge, and image forming apparatus

A processing cartridge, detachably mounted inside an image forming apparatus, comprising:

• a photosensitive drum cartridge;
• and
• a developing cartridge, wherein:
• the photosensitive drum cartridge includes a drum holder and a photosensitive drum mounted on the drum holder, wherein at least one sidewall of the drum holder is provided with a supporting part for mounting the developing cartridge;
• the developing cartridge is configured to be detachably mounted on the drum holder, the developing cartridge including a frame and a developing roller mounted on the frame, wherein at least one side-end surface of the frame is provided with a supported element cooperating with the supporting part of the photosensitive drum;
• and
• when the processing cartridge is mounted inside the image forming apparatus, the supported element receives a force applied by a force-applying component in the image forming apparatus, such that the developing roller is maintained pressed against the photosensitive drum, wherein:
• an angle between a direction of the force and a normal direction of a contact interface between the supported element and the supporting part is larger than or equal to a friction angle between the supported element and the supporting part.

An image forming apparatus, comprising:

• a main body, wherein a direction-guiding section is disposed in the main body;
• a processing cartridge, detachably mounted on the main body along the direction-guiding section, and including a photosensitive drum cartridge and a developing cartridge, wherein:
• the photosensitive drum cartridge includes a drum holder and a photosensitive drum mounted on the drum holder, wherein at least one sidewall of the drum holder is provided with a supporting part for mounting the developing cartridge;
• the developing cartridge is detachably mounted on the drum holder, and includes a frame and a developing roller mounted on the frame, wherein at least one side-end surface of the frame is provided with a supported element cooperating with the supporting part;
• and
• a force-applying component is disposed in the main body for applying a force to the developing cartridge, wherein:
• when the processing cartridge is mounted on the main body, the developing roller is maintained pressed against the photosensitive drum;
• and
• an angle between a direction of the force and a normal direction of a contact interface between the supported element and the supporting part is larger than or equal to a friction angle between the supported element and the supporting part.