Developing roller, and image forming apparatus

摘要

A developing roller is provided, which is capable of controlling a solid black density and a dot density at higher levels than currently available levels. An image forming apparatus employing the developing roller is also provided. The developing roller (1) includes a tubular base layer (4) of an elastic material, and a surface layer (6) of an elastic material provided on an outer peripheral surface (5) of the base layer (4), wherein the thickness d1 (mm) of the surface layer, the roller resistance R′ (log Ω as measured with an application voltage of 10 V) of the base layer, and the roller resistance R (log Ω as measured with an application voltage of 100 V) of a stack including the base layer and the surface layer satisfy the following expressions (1) to (3):
1.0≦R−R′  (1)0.1≦d1≦2  (2)7.5≦R≦8.5  (3)
The image forming apparatus incorporates the developing roller.

主权项

1. A developing roller comprising:
a tubular base layer of an elastic material; and a surface layer of an elastic material provided on an outer peripheral surface of the base layer; wherein a thickness d1 (mm) of the surface layer, a roller resistance R′ (log Ω as measured with an application voltage of 10 V) of the base layer, and a roller resistance R (log Ω as measured with an application voltage of 100 V) of a stack including the base layer and the surface layer satisfy the following expressions (1) to (3):
1.0≦R−R′  (1)0.1≦d1≦2  (2)7.5≦R≦8.5  (3).