DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

• Main Author: KIKUCHI MUTSUMI
• Format: Patent
• Language: English; Japanese
• Published: 22.03.2018
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To provide a developing device that comprises a rotating body rotating while facing, with a gap therebetween, a supply port through which toner is supplied to a storage part of a developer containing the toner and magnetic carrier, the developing device being capable of exerting a function to close the gap with the supply port by causing an outer peripheral surface of the rotating body to hold the developer, even if the rotating body includes a cylindrical member having no grooves formed in its outer peripheral surface.SOLUTION: A developing device comprises: a housing that includes a storage part for a developer containing toner and magnetic carrier; a supply port that is provided in the housing and through which the toner is supplied to the storage part; and a rotating body that is arranged on a lower side of the supply port of the housing with a gap between its outer peripheral surface and the supply port, and when a top face of the developer inside the storage part exceeds a reference height, conveys the developer while holding the developer on the outer peripheral surface by magnetic force to close the gap. The rotating body includes a cylindrical member having an outer peripheral surface with an arithmetic mean roughness (Ra) of Ra>4 μm.SELECTED DRAWING: Figure 4 【課題】トナーと磁性キャリアを含む現像剤の収容部にトナーが補給される補給口と隙間をあけて向き合って回転する回転体を備えた現像装置として、前記回転体が仮に外周面に溝が形成されない円筒部材を有するものであっても、その回転体の外周面に現像剤を保持させて補給口との隙間を塞ぐ機能を発揮させることができる現像装置等を提供する。【解決手段】現像装置は、トナーと磁性キャリアを含む現像剤の収容部を有する筐体と、前記筐体に設けられ、前記収容部にトナーを補給する補給口と、前記筐体の前記補給口の下方側に外周面が当該補給口と隙間をあけて配置され、前記収容部内の現像剤の上面が基準の高さを超えたときに前記現像剤を外周面に磁力で保持し搬送して前記隙間を塞ぐ回転体とを備え、前記回転体は、算術平均粗さ（Ra）がRa＞４μｍの外周面からなる円筒部材を有する。【選択図】図４