Canon Kabushiki Kaisha

Saki Tominaga

Kazuhiro Yamauchi

Tadashi Sato

Norifumi Muranaka

Yasuhiro Fushimoto

Yosuke Ata

Momosuke Takaichi

Takeshi Yoshidome

An electrophotographic electro-conductive member comprising an electro-conductive mandrel and an electro-conductive elastic layer on the electro-conductive mandrel, wherein the electro-conductive elastic layer has an elastic coefficient of 1 MPa or more and 100 MPa or less, as well as a matrix containing first rubber and a plurality of electro-conductive domains dispersed in the matrix. Each of the electro-conductive domains contains an electro-conductive particle, and the electro-conductive elastic layer includes regions containing second rubber in the circumferences of the electro-conductive domains. The matrix has an elastic coefficient R, the regions containing second rubber have an elastic coefficient R, and the elastic coefficients Rand Rsatisfy a relationship: R&#x3c;R.

Electrophotographic electro-conductive member having a dual rubber elastic layer, method of producing the same, process cartridge, and electrophotographic apparatus

A developing roller has a conductive shaft member, a conductive elastic layer formed around the shaft member in a thickness of 0.5 mm to 6.0 mm, and a surface layer. The elastic layer contains carbon black and silicone rubber. The carbon black is in a content of 7% to 17% by mass and has at least two peaks in its particle size number distribution. The minimum diameter peak center in the particle size number distribution is within the range of 10 nm to 40 nm. The elastic layer has density within the range of 1.01 g/cmto 1.07 g/cm. Where the ratios of carbon atoms to silicon atoms (C/Si), in the vicinity of the surface of the elastic layer, at depths of 100 &#x3bc;m and 200 &#x3bc;m from the surface of the elastic layer are represented by X, Y and Z, respectively, the X, Y and Z satisfy a specific relationship.

Developing roller, process for producing developing roller, process cartridge and image forming apparatus

Growing community of inventors

Suntou-gun, Japan

Saki Tominaga