Cartridge including photosensitive drum and developing roller that can be easily separated

A printer cartridge comprising:

• a drum unit including a photosensitive drum, and a first portion;
• a developing unit including developer, a developing roller, a developing frame provided with a chamber in which the developer is accommodated, a second portion, and a receiving portion configured to receive an external force, the developing unit being rotatably connected to the drum unit and configured to be rotatable relative to the drum unit about a rotational axis between:
• a first posture where the developing roller is in contact with the photosensitive drum in a state where the receiving portion is receiving the external force;
• and
• a second posture where the developing roller is separated from the photosensitive drum and a surface of the second portion is in contact with a surface of the first portion,
• wherein, in a state where the drum unit is in a predetermined posture and the developing unit is in the first posture, the rotational axis is directly below the developing roller, and the developing unit moves by its own weight to the second posture in a state where the external force is removed from the receiving portion, and
• wherein in a state where the drum unit is in the predetermined posture:
• a rotation center of the photosensitive drum is disposed higher than the rotational axis in relation to a vertical direction.

An image forming apparatus comprising:

• a drum unit including a photosensitive drum, and a first portion;
• a developing unit including developer, a developing roller, a developing frame provided with a chamber in which the developer is accommodated, a second portion, and a receiving portion configured to receive an external force, the developing unit being rotatably connected to the drum unit and configured to be rotatable relative to the drum unit about a rotational axis between:
• a first posture where the developing roller is in contact with the photosensitive drum in a state where the receiving portion is receiving the external force;
• and
• a second posture where the developing roller is separated from the photosensitive drum and a surface of the second portion is in contact with a surface of the first portion,
• wherein, in a state where the drum unit is in a predetermined posture and the developing unit is in the first posture, the rotational axis is directly below the developing roller, and the developing unit moves by its own weight to the second posture in a state where the external force is removed from the receiving portion, and
• wherein in a state where the drum unit is in the predetermined posture:
• a rotation center of the photosensitive drum is disposed higher than the rotational axis in relation to a vertical direction,
• wherein a printer cartridge is detachably mountable to a main body of the image forming apparatus along a rotational axis direction of the photosensitive drum, and
• wherein a transfer portion transfers a developer image borne by the photosensitive drum onto a recording medium.