Charging roll, process cartridge, and image forming apparatus

摘要

Provided is a charging roll, including a core body, and an elastic layer that is disposed on an outer circumferential surface of the core body, wherein, with respect to an approximation curve that extends an outer curve of the axial direction of the core body of an outer circumferential surface in a region other than both end portions of the outermost layer up to both end portions of the outermost layer, a maximum increase amount of the outer curve in both end portions of the outermost layer is equal to or less than 60 μm, and wherein a coefficient of friction of the outer circumferential surface at a position showing the maximum increase amount of the outer curve in both end portions of the outermost layer is equal to or less than 0.3, and a variation amount of the coefficient of friction is equal to or less than 30%.

主权项

1. A charging roll, comprising:
a core body in a cylindrical shape or in a columnar shape; and an elastic layer that is disposed on an outer circumferential surface of the core body in a cylindrical shape, wherein, when measuring an outer shape of an outermost layer along an axial direction of the core body, with respect to an approximation curve that extends an outer curve of the axial direction of the core body of an outer circumferential surface in a region other than both end portions of the outermost layer up to both end portions of the outermost layer, a maximum increase amount of the outer curve in both end portions of the outermost layer is equal to or less than 60 μm, wherein a coefficient of friction of the outer circumferential surface at a position showing the maximum increase amount of the outer curve in both end portions of the outermost layer is equal to or less than 0.3, and a variation amount of the coefficient of friction in a circumferential direction is equal to or less than 30%, and wherein each of the end portions of the outermost layer is a region within 50 mm in the axial direction of the core body from each axial end of the outermost layer, and the region other than both end portions is a region of a center part except the regions within 50 mm in the axial direction of the core body from each axial end of the outermost layer.