Magnetic roller, development device, and image forming method

A development device configured to develop a latent image with developer including toner and carrier includes a development roller configured to carry the developer. The development roller includes a stationary magnet-fixing member, a plurality of magnets fixed to an interior of the stationary magnet-fixing member to form a plurality of magnetic poles, and a cylindrical rotatable sleeve roller configured to revolve coaxially around the exterior of the magnet-fixing member. Magnetic force distribution of a portion of the plurality of magnetic poles is varied in an axial direction of the development roller at positions corresponding to an image forming area in the axial direction of the development roller, enabling the development device to transport and agitate the developer.