Process cartridge

A process cartridge attachable to an image forming apparatus, comprising:

• a photosensitive drum which is an image carrier;
• a developing roller configured to develop a toner image on the photosensitive drum;
• a supply roller configured to supply toner to the developing roller;
• a developing chamber having a support portion pivotally supporting the developing roller and the supply roller;
• a developing blade configured to regulate a layer thickness of toner on the developing roller;
• toner including toner particles having a volume average particle size R and an external additive;
• and
• a toner storage storing the toner,
• the toner storage communicating with the developing chamber via a communication port,
• a moving direction of a surface of the developing roller being opposite to a moving direction of a surface of the supply roller at a contact position with the supply roller,
• the developing blade including a plate-shaped metal elastic blade and a blade support portion supporting the elastic blade,
• in a cross section of the process cartridge in a plane perpendicular to a rotation shaft of the developing roller,
• in a posture in which a straight line A connecting rotation centers of the supply roller and the developing roller is inclined by about 9.85° from horizontal, a rotation shaft center of the supply roller is located below a rotation shaft center of the developing roller, and a rotation shaft center of the photosensitive drum is located above the straight line A, a portion where the elastic blade comes into contact with the developing roller being located below the rotation shaft center of the developing roller,
• the process cartridge further comprising:
• a driving force receiving portion;
• a first driving force transmitting portion configured to transmit a driving force from the driving force receiving portion to the supply roller;
• a second driving force transmitting portion disposed in the supply roller and configured to transmit a driving force received by the first driving force transmitting portion to the developing roller;
• and
• a third driving force transmitting portion disposed in the developing roller and configured to transmit a driving force from the second driving force transmitting portion to the developing roller, wherein
• the toner includes hydrotalcite particles as the external additive,
• fluorine is present inside the hydrotalcite particles in line analysis in STEM-EDS mapping analysis of the toner,
• in a cross section of the process cartridge in a plane perpendicular to the rotation shaft of the developing roller,
• the elastic blade forms a nip N1 with the developing roller and is in contact with the developing roller,
• a point at an end portion on an upstream side in a rotation direction of the developing roller in the nip N1 on the elastic blade is defined as a point D,
• a point which is closest to a free end side of the elastic blade and closest to a surface of the developing roller is defined as a point B,
• a point where a perpendicular line extending from the point B to the surface of the developing roller intersects with the surface of the developing roller is defined as E,
• there is a point F which is a point on a surface of the elastic blade whose distance from the surface of the developing roller is R and closest to the free end side of the elastic blade, and
• when a point on a straight line BE at which a distance from the surface of the developing roller is R is defined as G, a distance of GF is R or more.