Electrophotographic apparatus, process cartridge, and cartridge set

1. An electrophotographic apparatus comprising:

an electrophotographic photosensitive member,

a charging unit for charging a surface of the electrophotographic photosensitive member, and

a developing unit for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a toner to form a toner image on the surface of the electrophotographic photosensitive member, wherein

the charging unit comprises a conductive member disposed to be contactable with the electrophotographic photosensitive member;

the conductive member comprises:

a support having a conductive outer surface, and

a conductive layer disposed on this outer surface of the support;

the conductive layer comprises:

a matrix, and

a plurality of domains dispersed in the matrix;

the matrix contains a first rubber;

each of the domains contains a second rubber and an electronic conductive agent;

at least some of the domains are exposed at an outer surface of the conductive member;

the outer surface of the conductive member is constituted of at least the matrix and the domains that are exposed at the outer surface of the conductive member;

the matrix has a volume resistivity R1 of larger than 1.00×10 12 Ω·cm;

a volume resistivity R2 of the domains is smaller than the volume resistivity R1 of the matrix;

when G1 is Martens hardness in N/mm 2 measured on the matrix that is exposed at the outer surface of the conductive member and G2 is Martens hardness in N/mm 2 measured on the domains that are exposed at the outer surface of the conductive member, relationship G1<G2 is satisfied;

the outer surface of the conductive member has a surface roughness R a of not more than 2.00 μm;

the developing unit comprises the toner;

the toner comprises:

a toner particle containing a binder resin, and

an external additive externally added to the toner particle;

the external additive has primary particle having a shape factor SF-1 of not more than 115; and

when A is a number-average diameter of the primary particles of the external additive and Dms is an arithmetic average value of a distance between adjacent walls between the domains in the conductive layer in observation of the outer surface of the conductive member, A<Dms is satisfied.

2. The electrophotographic apparatus according to claim 1 , wherein the G1 and the G2 are both in a range from 1.0 N/mm 2 to 10.0 N/mm 2 .

3. The electrophotographic apparatus according to claim 1 , wherein the primary particles of the external additive have number-average particle diameter A of 30 to 200 nm.

4. The electrophotographic apparatus according to claim 1 , wherein the Dms is 0.15 to 2.00 μm.

5. The electrophotographic apparatus according to claim 1 , wherein, in observation of a cross section of the conductive member, an arithmetic average value Dm of a distance between adjacent walls of the domains in the conductive layer is 0.15 to 2.00 μm.

6. The electrophotographic apparatus according to claim 1 , wherein the external additive has indentation hardness at a load of 2 μN of 0.10 to 1.50 GPa.

7. The electrophotographic apparatus according to claim 1 , wherein the external additive comprises organosilicon polymer fine particles.

8. The electrophotographic apparatus according to claim 1 , wherein the external additive comprises polyalkylsilsesquioxane fine particles.

9. A process cartridge detachably provided to a main body of an electrophotographic apparatus, wherein

the process cartridge comprises a charging unit for charging a surface of an electrophotographic photosensitive member, and

a developing unit for developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a toner to form a toner image on the surface of the electrophotographic photosensitive member;

the charging unit comprises a conductive member disposed to be contactable with the electrophotographic photosensitive member;

the conductive member comprises:

a support having a conductive outer surface, and

a conductive layer disposed on this outer surface of the support;

the conductive layer comprises:

a matrix, and

a plurality of domains dispersed in the matrix;

the matrix contains a first rubber;

each of the domains contains a second rubber and an electronic conductive agent;

at least some of the domains are exposed at the outer surface of the conductive member;

the outer surface of the conductive member is constituted of at least the matrix and the domains that are exposed at the outer surface of the conductive member;

the matrix has a volume resistivity R1 of larger than 1.00×10 12 Ω·cm;

a volume resistivity R2 of the domains is smaller than the volume resistivity R1 of the matrix;

when G1 is Martens hardness in N/mm 2 measured on the matrix that is exposed at the outer surface of the conductive member and G2 is Martens hardness in N/mm 2 measured on the domains that are exposed at the outer surface of the conductive member, relationship G1<G2 is satisfied;

the outer surface of the conductive member has a surface roughness R a of not more than 2.00 μm;

the developing unit comprises the toner;

the toner comprises:

a toner particle containing a binder resin, and

an external additive externally added to the toner particle;

the external additive has primary particle having a shape factor SF-1 of not more than 115; and

when A is a number-average diameter of the primary particles of the external additive and Dms is an arithmetic average value of a distance between adjacent walls between the domains in the conductive layer in observation of the outer surface of the conductive member, A<Dms is satisfied.

10. A cartridge set comprising a first cartridge and a second cartridge detachably provided to a main body of an electrophotographic apparatus, wherein

the first cartridge comprises a charging unit for charging a surface of an electrophotographic photosensitive member and has a first frame for supporting the charging unit;

the second cartridge comprises a toner container that holds a toner for forming a toner image on the surface of the electrophotographic photosensitive member by developing an electrostatic latent image formed on the surface of the electrophotographic photosensitive member;

the charging unit comprises a conductive member disposed to be contactable with the electrophotographic photosensitive member;

the conductive member comprises:

a support having a conductive outer surface, and

a conductive layer disposed on this outer surface of the support;

the conductive layer comprises:

a matrix, and

a plurality of domains dispersed in the matrix;

the matrix contains a first rubber;

each of the domains contains a second rubber and an electronic conductive agent;

at least some of the domains are exposed at the outer surface of the conductive member;

the outer surface of the conductive member is constituted of at least the matrix and the domains that are exposed at the outer surface of the conductive member;

the matrix has a volume resistivity R1 of larger than 1.00×10 12 Ω·cm;

a volume resistivity R2 of the domains is smaller than the volume resistivity R1 of the matrix;

when G1 is Martens hardness in N/mm 2 measured on the matrix that is exposed at the outer surface of the conductive member and G2 is Martens hardness in N/mm 2 measured on the domains that are exposed at the outer surface of the conductive member, relationship G1<G2 is satisfied;

the outer surface of the conductive member has a surface roughness R a of not more than 2.00 μm;

the toner comprises:

a toner particle containing a binder resin, and

an external additive externally added to the toner particle;

the external additive has primary particle having a shape factor SF-1 of not more than 115; and

when A is a number-average diameter of the primary particles of the external additive and Dms is an arithmetic average value of a distance between adjacent walls between the domains in the conductive layer in observation of the outer surface of the conductive member, A<Dms is satisfied.