BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure is directed to a process cartridge and an electrophotographic apparatus.

Description of the Related Art

Electrophotographic apparatuses or process cartridges have been heretofore widely studied for suppression of deterioration in image quality in long-term use.

Japanese Patent Application Laid-Open No. 2002-003651 discloses a rubber composition having a sea-island structure including a polymer continuous phase including an ion conductive rubber material mainly including raw material rubber A having a volume specific resistivity of 1×1012Ω·cm or less and a polymer particle phase including an electron conductive rubber material obtained by compounding an electroconducting particle into raw material rubber B and making the resulting compound electroconductive, and a charging member having an elastic layer formed from the rubber composition.

Japanese Patent Application Laid-Open No. 2010-152338 describes an electrophotographic photosensitive member which is improved in wear resistance to the same level as in an amorphous silicon photosensitive member by forming a protective layer due to a reaction of a tin oxide particle having a reactive acryloyl group or methacryloyl group with a curable monomer. The Literature further describes the electrophotographic photosensitive member which is improved with respect to image deletion and image blurring easily caused under a high-temperature and high-humidity environment or the like and which allows an image high in durability and high in image quality to be obtained.

According to studies of the present inventors, the process cartridge and the electrophotographic apparatus, described in Japanese Patent Application Laid-Open No. 2002-003651 and Japanese Patent Application Laid-Open No. 2010-152338, have room for improvement with respect to the occurrence of any spot and stripe in long-term use.

SUMMARY OF THE INVENTION

One aspect of the present disclosure is directed to providing an electrophotographic apparatus and a process cartridge which can allow the occurrence of any spot and stripe to be suppressed even in long-term use.

According to one aspect of the present disclosure, a process cartridge detachably attachable to an electrophotographic apparatus body, including an electrophotographic photosensitive member and a charging member, is provided, wherein

the charging member includes a support having an electroconductive outer surface and an electroconductive layer provided on the outer surface of the support,

the electroconductive layer has a matrix including a first rubber, and a plurality of domains dispersed in the matrix,

the domains include a second rubber and an electron electroconductive agent,

at least some of the domains are exposed on an outer surface of the charging member,

the outer surface of the charging member is constituted by at least the matrix and at least some of the domains,

when a volume resistivity of the matrix is defined as Rcm and a volume resistivity of the domains is defined as Rcd, the Rcm is 1.0×105times or more the Rcd,

the electrophotographic photosensitive member includes a support, a photosensitive layer and a protective layer in the order listed,

the protective layer includes a metal oxide particle, and

when a number average primary particle size of the metal oxide particle is defined as Sm and an average value of equivalent circle diameters of the domains, as observed from the outer surface of the charging member, is defined as Sd, the Sd/Sm satisfies the following expression (1):
0.5<Sd/Sm<100  expression (1).

According to another aspect of the present disclosure, an electrophotographic apparatus including the above electrophotographic photosensitive member and the charging member is provided.

According to one aspect of the present disclosure, a process cartridge and an electrophotographic apparatus which allow the occurrence of any spot and stripe to be suppressed even in long-term use can be obtained.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

