Electrophotographic electro-conductive member, process cartridge, and electrophotographic image forming apparatus
Provided an electrophotographic electro-conductive member that can stably suppress an occurrence of fogging in an electrophotographic image. The member comprises a support having an electro-conductive outer surface, and an electro-conductive layer on the outer surface of the support, the electro-conductive layer having a matrix including a cross-linked product of a first rubber, and domains dispersed in the matrix, the domains each includes a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains is exposed to the outer surface of the electro-conductive member to constitute protrusions on an outer surface of the member, the outer surface of the electro-conductive member is constituted by the matrix and the domains exposed to the outer surface of the electrophotographic electro-conductive member, the electrophotographic electro-conductive member has an impedance of 1.0×10 3 Ω or more and 1.0×10 8 Ω or less, and some of the domains satisfy two specific requirements.
1. An electrophotographic electro-conductive member, comprising:
a support having an electro-conductive outer surface; and
an electro-conductive layer on the outer surface of the support;
the electro-conductive layer having a matrix with domains dispersed therein:
the matrix comprising a cross-linked product of a first rubber;
the domains each including a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains being exposed to an outer surface of the electrophotographic electro-conductive member to constitute protrusions on the outer surface of the electrophotographic electro-conductive member;
the outer surface of the electrophotographic electro-conductive member comprising the matrix and the domains that are exposed to the outer surface of the electrophotographic electro-conductive member, wherein
the electrophotographic electro-conductive member has an impedance of 1.0×10 3 to 1.0×10 8 Ω obtained by applying an alternating current voltage having an amplitude of 1 V and a frequency of 1.0 Hz between the outer surface of the support and a platinum electrode directly provided on the outer surface of the electrophotographic electro-conductive member under an environment of a temperature of 23° C. and a relative humidity of 50%, and
when defining a length of the electro-conductive layer in a longitudinal direction as L and a thickness of the electro-conductive layer as T, obtaining cross sections of the electro-conductive layer in a thickness direction thereof at a center position of the electro-conductive layer in the longitudinal direction and two positions corresponding to L/4 from both ends of the electro-conductive layer to the center of the electro-conductive layer in the longitudinal direction, and assuming that three observation areas each having a 15 μm square are arbitrary put in a thickness region of each of the cross sections between a depth of 0.1T to 0.9T from the outer surface of the electro-conductive layer, 80% or more of domains observed in the respective nine observation areas in total satisfy the following requirements (1) and (2):
(1) a proportion of a cross-sectional area of the electro-conductive particle included in a domain to be judged among the domains included in the observation areas to a cross-sectional area of the domain is 20% or more; and
(2) A/B is 1.00 to 1.10, where A is a perimeter of the domain, and B is an envelope perimeter of the domain.
2. The electrophotographic electro-conductive member according to claim 1 , wherein the matrix has a volume resistivity ρm of 1.0×10 8 to 1.0×10 17 Ω·cm.
3. The electrophotographic electro-conductive member according to claim 1 , wherein the domains satisfying requirements (1) and (2) have an average maximum Feret's diameter Df of 0.1 to 5.0 μm.
4. The electrophotographic electro-conductive member according to claim 1 , wherein the proportion satisfying requirement (1) is 25 to 30%.
5. The electrophotographic electro-conductive member according to claim 1 , wherein the electro-conductive particle is carbon black.
6. The electrophotographic electro-conductive member according to claim 5 , wherein the carbon black has a DBP adsorption amount of 40 to 80 cm 3 /100 g.
7. The electrophotographic electro-conductive member according to claim 5 , wherein the carbon black included in each of the domains satisfying requirements (1) and (2) have wherein an arithmetic mean wall-to-wall distance C of 110 to 130 nm, and
σ·m/C is 0.0 to 0.3 where a standard deviation of a wall-to-wall distance of the carbon black is defined as σ·m.
8. The electrophotographic electro-conductive member according to claim 1 , wherein a difference between absolute values of solubility parameters of the first and second rubbers is 0.4 to 4.0 (J/cm 3 ) 0.5 .
9. The electrophotographic electro-conductive member according to claim 1 , wherein each of the protrusions has a height of 50 to 200 nm.
10. The electrophotographic electro-conductive member according to claim 1 , wherein an arithmetic mean wall-to-wall distance Dm of the domains exposed to an outer surface of the electrophotographic electro-conductive member to constitute the protrusions is 2.00 μm or less.
11. The electrophotographic electro-conductive member according to claim 1 , wherein the matrix has a volume resistivity ρm of 1.0×10 10 to 1.0×10 17 Ω·cm.
12. The electrophotographic electro-conductive member according to claim 1 , wherein the matrix has a volume resistivity ρm of 1.0×10 12 to 1.0×10 17 Ω·cm.
13. An electrophotographic process cartridge detachably attachable to a main body of an electrophotographic image forming apparatus, the process cartridge comprising an electrophotographic electro-conductive member comprising:
a support having an electro-conductive outer surface; and
an electro-conductive layer on the outer surface of the support;
the electro-conductive layer having a matrix with domains dispersed therein;
the matrix comprising a cross-linked product of a first rubber;
the domains each including a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains being exposed to an outer surface of the electrophotographic electro-conductive member to constitute protrusions on the outer surface of the electrophotographic electro-conductive member;
the outer surface of the electrophotographic electro-conductive member comprising the matrix and the domains that are exposed to the outer surface of the electrophotographic electro-conductive member, wherein
the electrophotographic electro-conductive member has an impedance of 1.0×10 3 to 1.0×10 8 Ω obtained by applying an alternating current voltage having an amplitude of 1 V and a frequency of 1.0 Hz between the outer surface of the support and a platinum electrode directly provided on the outer surface of the electrophotographic electro-conductive member under an environment of a temperature of 23° C. and a relative humidity of 50%, and
when defining a length of the electro-conductive layer in a longitudinal direction as L and a thickness of the electro-conductive layer as T, obtaining cross sections of the electro-conductive layer in a thickness direction thereof at a center position of the electro-conductive layer in the longitudinal direction and two positions corresponding to L/4 from both ends of the electro-conductive layer to the center of the electro-conductive layer in the longitudinal direction, and assuming that three observation areas each having a 15 μm square are arbitrary put in a thickness region of each of the cross sections between a depth of 0.1T to 0.9T from the outer surface of the electro-conductive layer, 80% or more of domains observed in the respective nine observation areas in total satisfy the following requirements (1) and (2):
(1) a proportion of a cross-sectional area of the electro-conductive particle included in a domain to be judged among the domains included in the observation areas to a cross-sectional area of the domain is 20% or more; and
(2) A/B is 1.00 to 1.10, where A is a perimeter of the domain, and B is an envelope perimeter of the domain.
14. The process cartridge according to claim 13 , wherein the electrophotographic electro-conductive member is configured to function as a charging member.
15. An electrophotographic image forming apparatus comprising an electrophotographic electro-conductive member comprises:
a support having an electro-conductive outer surface; and
an electro-conductive layer on the outer surface of the support;
the electro-conductive layer having a matrix with domains dispersed therein;
the matrix comprising a cross-linked product of a first rubber;
the domains each including a cross-linked product of a second rubber and an electro-conductive particle, at least some of the domains being exposed to an outer surface of the electrophotographic electro-conductive member to constitute protrusions on the outer surface of the electrophotographic electro-conductive member;
the outer surface of the electrophotographic electro-conductive member comprising the matrix and the domains that are exposed to the outer surface of the electrophotographic electro-conductive member, wherein
the electrophotographic electro-conductive member has an impedance of 1.0×10 3 to 1.0×10 8 Ω obtained by applying an alternating current voltage having an amplitude of 1 V and a frequency of 1.0 Hz between the outer surface of the support and a platinum electrode directly provided on the outer surface of the electrophotographic electro-conductive member under an environment of a temperature of 23° C. and a relative humidity of 50%, and
when defining a length of the electro-conductive layer in a longitudinal direction as L and a thickness of the electro-conductive layer as T, obtaining cross sections of the electro-conductive layer in a thickness direction thereof at a center position of the electro-conductive layer in the longitudinal direction and two positions corresponding to L/4 from both ends of the electro-conductive layer to the center of the electro-conductive layer in the longitudinal direction, and assuming that three observation areas each having a 15 μm square are arbitrary put in a thickness region of each of the cross sections between a depth of 0.1T to 0.9T from the outer surface of the electro-conductive layer, 80% or more of domains observed in the respective nine observation areas in total satisfy the following requirements (1) and (2):
(1) a proportion of a cross-sectional area of the electro-conductive particle included in a domain to be judged among the domains included in the observation areas to a cross-sectional area of the domain is 20% or more; and
(2) A/B is 1.00 to 1.10, where A is a perimeter of the domain, and B is an envelope perimeter of the domain.
16. The electrophotographic image forming apparatus according to claim 15 , wherein the electrophotographic electro-conductive member is configured to function as a charging member.