Electroconductive member, process cartridge, and image forming apparatus
Provided is an electrophotographic electroconductive member including an electroconductive support and an electroconductive layer on the support, an electroconductive member is used, in which an electroconductive layer has a matrix comprising a first rubber, and domains dispersed in the matrix, the domains each comprising a second rubber and an electronic electroconductive agent, and for impedance measured by applying an AC voltage with an amplitude of 1 V to the electroconductive layer while varying frequencies between 1.0×10 −2 Hz to 1.0×10 7 Hz under a specific environment, when a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate is obtained, a slope on a high frequency side is −0.8 or more and −0.3 or less, and the impedance a low frequency side is from 1.0×10 3 to 1.0×10 7 Ω.
1. An electrophotographic electroconductive member comprising:
a support having an electroconductive outer surface; and
an electroconductive layer on the electroconductive outer surface of the support,
the electroconductive layer having a matrix comprising a first rubber, and domains dispersed in the matrix,
the domains each comprising a second rubber and an electronic electroconductive agent, wherein
assuming that a metal film is provided on the electroconductive outer surface of the electroconductive member, and impedance is measured by applying an AC voltage with an amplitude of 1 V between the electroconductive outer surface of the support and the metal film while varying a frequency between 1.0×10 −2 Hz to 1.0×10 7 Hz under an environment of a temperature of 23° C. and a humidity of 50% RH, in a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate, a slope at frequencies of 1.0×10 5 Hz to 1.0×10 6 Hz is −0.8 or more and −0.3 or less, and an impedance at frequency of 1.0×10 −2 Hz to 1.0×10 1 Hz is 1.0×10 3 to 1.0×10 7 Ω.
2. The electroconductive member according to claim 1 , wherein the electroconductive layer is directly provided on the electroconductive outer surface of the support.
3. The electroconductive member according to claim 1 , further comprising an electroconductive resin layer between the electroconductive layer and the electroconductive outer surface of the support,
assuming that a metal film is provided on an outer surface of the resin layer, and impedance is measured by applying an AC voltage with an amplitude of 1 V between the electroconductive outer surface of the support and the metal film while varying a frequency between 1.0×10 −2 Hz to 1.0×10 7 Hz under an environment of a temperature of 23° C. and a humidity of 50% RH, in a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate, an impedance at 1.0×10 −2 Hz to 1.0×10 1 Hz is 1.0×10 −5 to 1.0×10 2 Ω.
4. The electroconductive member according to claim 1 , wherein volume resistivity of the matrix is more than 1.0×10 12 Ω·cm and 1.0×10 17 Ω·cm or less.
5. The electroconductive member according to claim 1 , wherein an arithmetic average value Dm of a distance between the domains is 0.2 μm or more and 2.0 μm or less.
6. The electroconductive member according to claim 1 , wherein the support is a cylindrical support, and the electroconductive layer is provided on an outer peripheral surface of the cylindrical support.
7. The electrophotographic electroconductive member according to claim 6 , wherein
defining a length of the cylindrical support of the electroconductive layer in the longitudinal direction as L, and
defining a thickness of the electroconductive layer as T, and
assuming that three cross sections of the electroconductive layer in a thickness direction thereof at a center in the longitudinal direction of the electroconductive layer, and L/4 from both ends of the electroconductive layer toward the center, are obtained, where L represents a length of the electroconductive layer in the longitudinal direction of the cylindrical support, and
assuming that at each of the cross sections, three square observation areas each having 15 μm a side, are arbitrary placed in a thickness region from 0.1 T to 0.9 T in depth from the outer surface of the electroconductive layer, where T represents a thickness of the electroconductive layer,
among domains observed in each of the nine observation areas, 80% by number or more of the domains satisfy the following requirements (1) and (2):
(1) a ratio of a cross-sectional area of a part containing the electronic electroconductive agent contained in the domain to a cross-sectional area of the domain is 20% or more; and
(2) when defining a perimeter of the domain as A, and defining an envelope perimeter of the domain as B, A/B is 1.00 or more and 1.10 or less.
8. The electroconductive member according to claim 1 , wherein when defining the arithmetic average value of an equivalent circle diameter of the domain as D and a standard deviation of distribution of the D as σd, a variation coefficient σd/D of the equivalent circle diameter of the domain is 0 or more and 0.4 or less.
9. The electroconductive member according to claim 1 , wherein when defining the arithmetic average value of the inter-domain surface distances as Dm and the standard deviation of distribution of Dm as σm, the variation coefficient σm/Dm of the inter-domain surface distances is 0 or more and 0.4 or less.
10. The electroconductive member according to claim 1 , wherein when a mean value of ratios of cross-sectional areas of moieties of the electroconductive agent contained in each of the domains appearing in a cross section in the thickness direction of the electroconductive layer to each of cross-sectional areas of the respective domains is defined as μr, a standard deviation of the ratios is defined as σr, a coefficient of variation σr/μr of the ratios of the cross-sectional areas of the moieties of the electroconductive agent is 0 or more and 0.4 or less.
11. The electroconductive member according to claim 1 , wherein the electroconductive member is a charging member.
12. The electroconductive member according to claim 1 , wherein the electroconductive member is a transfer member.
13. A process cartridge configured to be detachably attachable to a main body of an electrophotographic image forming apparatus, the process cartridge for electrophotography comprising an electroconductive member,
the electrophotographic electroconductive member including:
a support having an electroconductive outer surface; and
an electroconductive layer on the electroconductive outer surface of the support,
the electroconductive layer having a matrix comprising a first rubber, and domains dispersed in the matrix,
the domains each comprising a second rubber and an electronic electroconductive agent, wherein
assuming that a metal film is provided on the electroconductive outer surface of the electroconductive member, and impedance is measured by applying an AC voltage with an amplitude of 1 V between the electroconductive outer surface of the support and the metal film while varying a frequency between 1.0×10 −2 Hz to 1.0×10 7 Hz under an environment of a temperature of 23° C. and a humidity of 50% RH, in a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate, a slope at frequencies of 1.0×10 5 Hz to 1.0×10 6 Hz is −0.8 or more and −0.3 or less, and an impedance at frequency of 1.0×10 −2 Hz to 1.0×10 1 Hz is 1.0×10 3 to 1.0×10 7 Ω.
14. An electrophotographic image forming apparatus comprising an electroconductive member,
the electrophotographic electroconductive member including:
a support having an electroconductive outer surface; and
an electroconductive layer on the electroconductive outer surface of the support,
the electroconductive layer having a matrix comprising a first rubber, and domains dispersed in the matrix,
the domains each comprising a second rubber and an electronic electroconductive agent, wherein
assuming that a metal film is provided on the electroconductive outer surface of the electroconductive member, and impedance is measured by applying an AC voltage with an amplitude of 1 V between the electroconductive outer surface of the support and the metal film while varying a frequency between 1.0×10 −2 Hz to 1.0×10 7 Hz under an environment of a temperature of 23° C. and a humidity of 50% RH, in a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate, a slope at frequencies of 1.0×10 5 Hz to 1.0×10 6 Hz is −0.8 or more and −0.3 or less, and an impedance at frequency of 1.0×10 −2 Hz to 1.0×10 1 Hz is 1.0×10 3 to 1.0×10 7 Ω.