Development device, process cartridge, and image forming apparatus including same

A development device to develop a latent image formed on a latent image bearer with two-component developer, the development device comprising:

• a casing;
• a developer container housed in the casing, for containing the developer;
• a hollow, cylindrical developer bearer positioned facing the latent image bearer to transport by rotation the developer to a development range where the developer forms a magnetic brush and slides on the latent image bearer;
• a magnetic field generator disposed inside the developer bearer;
• a developer agitator to supply the developer contained in the developer container to the developer bearer while transporting the developer in an axial direction of the developer bearer;
• and
• a developer regulator positioned upstream from the development range in a rotational direction of the developer bearer across a predetermined gap from an outer circumferential surface of the developer bearer to adjust a layer thickness of the developer carried on the developer bearer,
• wherein multiple oval recesses oblique to the axial direction of the developer bearer are formed in the outer circumferential surface of the developer bearer and arranged in a circumferential direction of the developer bearer and the axial direction of the developer bearer,
• an upstream inner wall of each of the multiple recesses on an upstream side in the rotational direction of the developer bearer applies a force to the developer as the developer bearer rotates, and
• an angle between a long axis of each of the multiple recesses and the axial direction of the developer bearer is set so that the force applied by the upstream inner wall of each recess has a component in a direction substantially identical to the direction in which the developer agitator transports the developer.