Canon Kabushiki Kaisha

Katsuya Kodama

Toshiro Suzuki

Atsushi Uematsu

Kenichi Yazawa

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as Xl, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6&#xd7;(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do&#x2212;DX1)/2 and Z2=(DX1&#x2212;DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)&#x3c;1.931&#xd7;(Z1/L1).

Electrophotographic roller, process cartridge and electrophotographic image forming apparatus

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as X1, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6&#xd7;(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do&#x2212;DX1)/2 and Z2=(DX1&#x2212;DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)&#x3c;1.931&#xd7;(Z1/L1).

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Kanagawa, Japan

Katsuya Kodama