DEVELOPMENT DEVICE, IMAGE FORMATION DEVICE AND CARTRIDGE

To provide a development device, image formation device and cartridge that can prevent image failures due to a difference between degrees of deterioration of developer containing magnetic substance in a rotation axial line direction of a developer carrier.SOLUTION: A development device has: developer that contains a magnetic substance; a rotatable developer carrier that carries the developer for developing a latent image formed on an image carrier; a developer storage chamber that stores the developer to be supplied to the developer carrier; a rotatable agitation member that is arranged inside the developer storage chamber, and agitates the developer as contacting with at least one part of an inner wall of the developer storage chamber; and a magnetic field generation member that generates in at least one part of a contact area where the inner wall and the agitation member contact with each other. The magnetic field generation member is arranged so that magnetic flux density of the magnetic field in the contact area is made different between a first location and a second location adjacent to the first position in the rotation axial line direction of the developer carrier.SELECTED DRAWING: Figure 1 【課題】現像剤担持体の回転軸線方向において、磁性体を含有する現像剤の劣化度の違いによる画像不良を抑制できる現像装置および画像形成装置並びにカートリッジを提供する。【解決手段】磁性体を含有する現像剤と、像担持体上に形成された潜像を現像するために前記現像剤を担持する回転可能な現像剤担持体と、前記現像剤担持体に供給される前記現像剤を収容する現像剤収容室と、前記現像剤収容室の内部に配置され、前記現像剤収容室の内壁の少なくとも一部と接触しながら前記現像剤を撹拌する回転可能な撹拌部材と、前記内壁と前記撹拌部材が接触する接触領域の少なくとも一部に磁界を発生する磁界発生部材と、を有する現像装置で、前記磁界発生部材は、前記接触領域における前記磁界の磁束密度が、第一の位置と、前記現像剤担持体の回転軸線方向で前記第一の位置と隣接する第二の位置とで異なるように配置される。【選択図】図１