Process cartridge and electrophotographic image forming apparatus

A process cartridge comprising:

• a developer,
• a developer carrying member,
• a developer layer thickness control member that contacts the developer carrying member and controls a layer thickness of the developer carried on the developer carrying member,
• a contact that is electrically connected to the developer layer thickness control member, and
• a developer storage member that stores the developer, wherein
• the process cartridge is detachably attached to a main body of an electrophotographic image forming apparatus,
• at least a part of the developer layer thickness control member is electrically conductive,
• where the process cartridge is attached to the main body of the electrophotographic image forming apparatus, the contact is electrically connected to a main body contact of the main body of the electrophotographic image forming apparatus, and a predetermined voltage can be applied to the developer layer thickness control member,
• the developer carrying member comprises
• a substrate comprising a conductive outer surface, and
• a resin layer present on a side of the outer surface of the substrate,
• where a metal film is provided directly on an outer surface of the developer carrying member, and an AC voltage with an amplitude of 50 V is applied with a frequency being changed between 1.0×10−1 to 1.0×105 Hz while applying a DC voltage of 50 V between the outer surface of the substrate and the metal film in an environment of a temperature of 23° C. and a relative humidity of 50%, an impedance at a frequency of 1.0×100 to 1.0×101 Hz is 1.00×106Ω or more,
• where an ionization potential of the developer is denoted by I(T) and an ionization potential of the outer surface of the developer carrying member is denoted by I(R), I(T) and I(R) satisfy following formula (X):
• ❘
• "\[LeftBracketingBar]"
• I
• ⁢
• (
• T
• )
• -
• I
• ⁢
• (
• R
• )
• ❘
• "\[RightBracketingBar]"
• ≤
• 0.3
• eV
• (
• X
• )
• and where a corona discharger that has a grid portion with a width of 3.0 mm is arranged such that a distance between the grid portion and the outer surface of the developer carrying member is 1.0 mm and a width direction of the grid portion coincides with an axial direction of the developer carrying member in an environment with a temperature of 23° C. and a relative humidity of 50%, a voltage of 8 kV is applied to the grid portion, the corona discharger is moved along the axial direction of the developer carrying member relative thereto at a speed of 400 mm/sec to charge the outer surface of the developer carrying member, and a potential of the outer surface is measured 0.06 sec after passing the grid portion, the maximum value of the potential is less than 20.0 V.