Patent ID: 8909108

Claim:
A developing device comprising: a first developer bearing member having a surface provided with a plurality of grooves, the first developer bearing member being configured to bear a developer containing at least magnetic particles on the surface with a magnetic force, and to convey the developer to a first developing region opposite an image bearing member; and a second developer bearing member having a surface provided with a plurality of grooves, the second developer bearing member being configured to rotate in the same rotational direction as the first developer bearing member, to receive the developer from the first developer bearing member at a site opposite the first developer bearing member, and to bear the received developer on the surface with a magnetic force to convey the received developer to a second developing region opposite the image bearing member, wherein an angle θ 1 that a surface, which is located upstream in the rotational direction, of each groove in the first developer bearing member forms with a normal to the first developer bearing member is larger than an angle θ 2 that a surface, which is located upstream in the rotational direction, of each groove in the second developer bearing member forms with a normal to the second developer bearing member.