Electro-conductive member, method for producing same, process cartridge and electrophotographic image forming apparatus

A method for producing the electrophotographic electro-conductive member comprising an electro-conductive layer containing:

• a matrix containing a crosslinked product of a first rubber;
• and
• domains dispersed in the matrix,
• each of the domains containing a crosslinked product of a second rubber and electro-conductive particles,
• the first rubber being different from the second rubber, wherein
• when an average of ratios of the cross-sectional area of the electro-conductive particles contained in each of the domains to the cross-sectional area of each of the domains appearing on a cross-section of the electro-conductive layer in a thickness direction is defined as μ, and a standard deviation of the ratios is defined as σ,
• σ/μ is 0 or more and 0.4 or less,
• μ is 20% or more and 40% or less, and wherein
• among first cubic shaped samples each having 9 μm on a side sampled at arbitrary nine portions from the electro-conductive layer, at least eight of the samples satisfy the following condition (1):
• Condition (1)
• assuming that one sample is divided into 27 unit cubes having 3 μm on a side, and a volume Vd of the domains contained in each of the unit cubes is calculated, a number of the unit cubes having Vd of 2.7 to 10.8 μm3 is at least 20, the method comprising the steps of:
• (1) kneading an unvulcanized rubber mixture containing a first unvulcanized rubber as a raw material of the first rubber, a second unvulcanized rubber as a raw material of the second rubber and the electro-conductive particles by using a kneader including an elongational shear screw to prepare an unvulcanized rubber kneaded product;
• (2) forming a layer of the unvulcanized rubber kneaded product on an outer surface of the electro-conductive substrate;
• and
• (3) vulcanizing the first unvulcanized rubber and the second unvulcanized rubber in the layer of the unvulcanized rubber kneaded product to prepare the electro-conductive layer.